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fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.13.4.1 General | If the 5GS supports Emergency Services, the support is indicated to UE via the Registration Accept message on per-TA-list and per-RAT basis, as described in TS 23.501 [2].
If the 5GS supports Emergency Services Fallback, the support is indicated to UE via the Registration Accept message on per-TA-list and per-RAT basis, as described in TS 23.501 [2].
The UE shall follow the domain selection rules for emergency session attempts as described in TS 23.167 [28].
If the 5GC has indicated Emergency Services Fallback support for the TA and RAT where the UE is currently camping and if the UE supports emergency services fallback, the UE shall initiate the Emergency Services Fallback procedure described in clause 4.13.4.2.
At QoS Flow establishment request for Emergency Services, the procedure described in clause 4.13.6.2 Inter RAT Fallback in 5GC for IMS voice or the procedure described in clause 4.13.6.1 EPS fallback for IMS voice may be triggered by the network, when configured. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.13.4.2 Emergency Services Fallback | The call flow in Figure 4.13.4.2-1 describes the procedure for emergency services fallback.
Figure 4.13.4.2-1: Emergency Services Fallback
1. UE camps on E-UTRA or NR cell in the 5GS (in either CM-IDLE or CM-CONNECTED state).
2. UE has a pending IMS emergency session request (e.g. voice) from the upper layers.
3. If the AMF has indicated support for emergency services using fallback via the Registration Accept message for the current RAT, the UE sends a Service Request message indicating that it requires emergency services fallback. The UE is not required to include the PDU Sessions that are not relevant for the emergency service in the List Of PDU Sessions to be Activated in the Service Request for the emergency service.
NOTE 1: If the UE includes PDU Sessions to be Activated in the Service Request for the emergency service, it will delay the Emergency Services Fallback procedure.
4. 5GC triggers a request for Emergency Services Fallback by executing an NG-AP procedure in which it indicates to NG-RAN that this is a fallback for emergency services. The AMF based on the support of Emergency Services in EPC or 5GC may indicate the target CN for the RAN node to know whether inter-RAT fallback or inter-system fallback is to be performed. When AMF initiates Redirection for UE(s) that have been successfully authenticated, AMF includes the security context in the request to trigger fallback towards NG-RAN.
5. Based on the target CN if indicated in message 4 or otherwise based on the RAN configuration, one of the following procedures is executed by NG-RAN:
5a. NG-RAN initiates handover (see clause 4.9.1.3) or redirection to a 5GC-connected E-UTRAN cell, if UE is currently camped on NR.
5b. NG-RAN initiates handover (see clause 4.11.1.2.1) or redirection to E-UTRAN connected to EPS. NG-RAN uses the security context provided by the AMF to secure the redirection procedure.
If the redirection procedure is used either in 5a or 5b the target CN type (EPC or 5GC) is also conveyed to the UE in order to be able to perform the appropriate NAS procedures (S1 or N1 Mode). The UE uses the emergency indication in the RRC message as specified in clause 6.2.2 of TS 36.331 [16] and E-UTRAN provides the emergency indication to AMF (during Registration triggered by step 5a) and MME (during Tracking Area Update triggered by step 5b). Both the Registration and the Tracking Area Update requests should contain Follow-on request and active flag respectively to indicate that the UE has "user data pending". For the handover procedure used in step 5b see clause 4.11.1.2.1, step 1.
In step 5b, if the MME does not support emergency services for that UE, the MME should act such that the call for emergency service is likely to succeed promptly, e.g. if the UE successfully completed a combined TA/LA Update with the network, by using the CSFB procedures specified in TS 23.272 [61].
NOTE 2: If such a combined TA/LA Update is not successful, or the UE did not request a combined update, then, as specified in TS 23.167 [28], the UE autonomously selects a RAT that may (but which might not) support the CS domain.
6. After handover or redirection to the target cell the UE establishes a PDU Session / PDN connection for IMS emergency services and performs the IMS procedures for establishment of an IMS emergency session (e.g. voice) as defined in TS 23.167 [28].
At least for the duration of the emergency voice call, the E-UTRAN connected to EPC is configured to not trigger any handover to 5GS and the target NG-RAN is configured to not trigger inter NG-RAN handover back to source NG-RAN. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.13.5 Location Services procedures | |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.13.5.0 General | Location Service procedures are defined in TS 23.273 [51]. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.13.5.1 5GC-NI-LR Procedure | Location Service procedures are defined in TS 23.273 [51]. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.13.5.2 5GC-MT-LR Procedure without UDM Query | Location Service procedures are defined in TS 23.273 [51]. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.13.5.3 5GC-MT-LR Procedure | Location Service procedures are defined in TS 23.273 [51]. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.13.5.4 UE Assisted and UE Based Positioning Procedure | Location Service procedures are defined in TS 23.273 [51]. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.13.5.5 Network Assisted Positioning Procedure | Location Service procedures are defined in TS 23.273 [51]. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.13.5.6 Obtaining Non-UE Associated Network Assistance Data | Location Service procedures are defined in TS 23.273 [51]. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.13.5.7 Location continuity for Handover of an Emergency session from NG-RAN | Location Service procedures are defined in TS 23.273 [51]. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.13.6 Support of IMS Voice | |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.13.6.1 EPS fallback for IMS voice | Figure 4.13.6.1-1 describes the EPS fallback procedure for IMS voice.
When the UE is served by the 5G System, the UE has one or more ongoing PDU Sessions each including one or more QoS Flows. The serving PLMN AMF has sent an indication towards the UE during the Registration procedure that IMS voice over PS session is supported, see clause 5.16.3.10 of TS 23.501 [2] and the UE has registered in the IMS. If N26 is not supported, the serving PLMN AMF sends an indication towards the UE during the Registration procedure that interworking without N26 is supported, see clause 5.17.2.3.1 of TS 23.501 [2].
Figure 4.13.6.1-1: EPS Fallback for IMS voice
1. UE camps on NG-RAN in the 5GS and an MO or MT IMS voice session establishment has been initiated.
2. Network initiated PDU Session modification to setup QoS flow for voice reaches the NG-RAN (see N2 PDU Session Request in clause 4.3.3).
3. NG-RAN is configured to support EPS fallback for IMS voice and decides to trigger fallback to EPS, taking into account UE capabilities, indication from AMF that "Redirection for EPS fallback for voice is possible" (received as part of initial context setup, handover resource allocation or path switch request acknowledge as defined in TS 38.413 [10]), network configuration (e.g. N26 availability configuration) and radio conditions. If NG-RAN decides not to trigger fallback to EPS, then the procedure stops here and following steps are not executed.
NG-RAN may initiate measurement report solicitation from the UE including E-UTRAN as target.
NOTE: If AMF has indicated that "Redirection for EPS fallback for voice is not possible", then EPS fallback for IMS voice is not performed in step 5. If NG-RAN has not received indication "Redirection for EPS fallback for voice", the decision to execute EPS fallback for IMS voice or not is based on network configuration (e.g. based on N26 availability and other criteria).
4. NG-RAN responds indicating rejection of the PDU Session modification to setup QoS flow for IMS voice received in step 2 by PDU Session Modification Response message towards the SMF+PGW-C (or H-SMF+P-GW-C via V-SMF, in the case of home routed roaming scenario) via AMF with an indication that mobility due to fallback for IMS voice is ongoing. The SMF+PGW-C maintains the PCC rule(s) associated with the QoS Flow(s) and reports the EPS Fallback event to the PCF if PCF has subscribed to this event.
5. NG-RAN initiates either handover (see clause 4.11.1.2.1), or AN Release via inter-system redirection to EPS (see clause 4.2.6 and clause 4.11.1.3.2), taking into account UE capabilities. The SMF+PGW-C reports change of the RAT type if subscribed by PCF as specified in clause 4.11.1.2.1, or clause 4.11.1.3.2.
6. When the UE is connected to EPS, either 6a or 6b is executed:
6a. In the case of 5GS to EPS handover, see clause 4.11.1.2.1 and in the case of inter-system redirection to EPS with N26 interface, see clause 4.11.1.3.2. In either case the UE initiates TAU procedure and the UE includes active flag in the request in the case of inter-system redirection to EPS; or
6b. In the case of inter-system redirection to EPS without N26 interface, see clause 4.11.2.2. If the UE supports Request Type flag "handover" for PDN connectivity request during the attach procedure as described in clause 5.3.2.1 of TS 23.401 [13] and has received the indication that interworking without N26 is supported, then the UE initiates Attach with PDN connectivity request with request type "handover".
In the case of inter-system redirection for the emergency service, the UE uses the emergency indication in the RRC message as specified in clause 6.2.2 of TS 36.331 [16] and E-UTRAN provides the emergency indication to MME during Tracking Area Update or Attach procedure. For the handover procedure see clause 4.11.1.2.1, step 1.
7. After completion of the mobility procedure to EPS or as part of the 5GS to EPS handover procedure, the SMF+PGW-C re-initiates the setup of the dedicated bearer(s) for the maintained PCC rule(s) in step 4 including of the dedicated bearer for IMS voice, mapping the 5G QoS to EPC QoS parameters as specified in clause 4.11.1.2.1. The SMF+PGW-C reports about Successful Resource Allocation and Access Network Information if subscribed by PCF.
The IMS signalling related to IMS voice call establishment continues after step 1 as specified in the TS 23.228 [55].
At least for the duration of the voice call in EPS the E-UTRAN is configured to not trigger any handover to 5GS. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.13.6.2 Inter RAT Fallback in 5GC for IMS voice | Figure 4.13.6.2-1 describes the RAT fallback procedure in 5GC for IMS voice.
When the UE is served by the 5GC, the UE has one or more ongoing PDU Sessions each including one or more QoS Flows. The serving PLMN AMF has sent an indication towards the UE during the Registration procedure that IMS voice over PS session is supported, see clause 5.16.3.10 of TS 23.501 [2] and the UE has registered in the IMS.
Figure 4.13.6.2-1: RAT Fallback for IMS voice
1. UE camps on source NG-RAN in the 5GS and an MO or MT IMS voice session establishment has been initiated.
2. Network initiated PDU Session modification to setup QoS flow for IMS voice reaches the source NG-RAN (see N2 PDU Session Request in clause 4.3.3).
3. If source NG-RAN is configured to support RAT fallback for IMS voice, source NG-RAN decides to trigger RAT fallback, taking into account on UE capabilities, network configuration and radio conditions.
Source NG-RAN may initiate measurement report solicitation from the UE including target NG-RAN.
4. Source NG-RAN responds indicating rejection of the PDU Session modification to setup QoS flow for IMS voice received in step 2 by PDU Session Response message towards the SMF (or V-SMF, in the case of roaming scenario) via AMF with an indication that mobility due to fallback for IMS voice is ongoing. The SMF maintains the PCC rule(s) associated with the QoS Flow(s).
5. Source NG-RAN initiates Xn based Inter NG-RAN handover (see clause 4.9.1.2) or N2 based inter NG-RAN handover (see clause 4.9.1.3), or redirection to E-UTRA connected to 5GC (see clause 4.2.6). The SMF reports change of the RAT type if subscribed by PCF.
6. After completion of the Inter NG-RAN (inter-RAT) handover or redirection to E-UTRA connected to 5GC, the SMF re-initiates the PDU Session modification to setup QoS flow for IMS voice. The SMF reports about Successful Resource Allocation and Access Network Information if subscribed by PCF.
The IMS signalling related to IMS voice call establishment continues after step 1 as specified in TS 23.228 [55].
At least for the duration of the IMS voice call the target NG-RAN is configured to not trigger inter NG-RAN handover back to source NG-RAN. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.13.6.3 Transfer of PDU session used for IMS voice from non-3GPP access to 5GS | Figure 4.13.6.3-1: Transfer of PDU session used for IMS voice from non-3GPP access to 5GS
When the UE has an ongoing IMS voice session via non-3GPP access using ePDG or N3IWF and the session is transferred to NG-RAN, depending on the selected RAT in 5GS (NR or E-UTRA) and the support of EPS/inter-RAT fallback in NG-RAN, either the IMS voice session continues over NG-RAN (E-UTRA) or EPS/inter-RAT fallback is triggered.
Steps 1, 2 and 3 apply to either of the above two cases.
1. UE has ongoing IMS voice session via non-3GPP access using ePDG or N3IWF. UE is triggered to move to 3GPP access and camps in NG-RAN.
2. If the UE is not registered via 3GPP access, the UE shall initiate Registration procedure as defined in clause 4.2.2.2.2.
3. UE initiates PDU session establishment for the PDU session used for IMS voice service in order to initiate handover from EPC/ePDG to 5GS as defined in clause 4.11.4.1 step 2 or to initiate handover from N3IWF to 3GPP access in 5GC in step 2 of clauses 4.9.2.1 and 4.9.2.3. The SMF accepts the PDU session transfer from the UE.
NOTE 1: If the UE is aware (e.g. implementation-dependent mechanisms) that voice over NR may not be natively supported in the current Registration area, the UE can attempt to move to E-UTRA to initiate a handover of the IMS PDU Session to EPC or 5GC to continue the IMS voice session. The remaining steps are not executed.
4. NG-RAN may decide to trigger EPS or inter-RAT fallback, taking into account UE capabilities, indication from AMF that "Redirection for EPS fallback for voice is possible" (received as part of initial context setup as defined in TS 38.413 [10]), network configuration (e.g. N26 availability configuration) and radio conditions. NG-RAN may initiate measurement report solicitation from the UE including E-UTRA as target.
If NG-RAN does not trigger EPS or inter-RAT fallback, then the procedure stops here and following steps are not executed.
NOTE 2: If the AMF has indicated that "Redirection for EPS fallback for voice is not possible", then EPS fallback for IMS voice is not performed. If NG-RAN has not received indication "Redirection for EPS fallback for voice", the decision to execute EPS fallback for IMS voice or not is based on network configuration (e.g. based on N26 availability and other criteria).
5. NG-RAN responds indicating rejection either to set up the QoS flow for IMS voice or the entire PDU session used for IMS voice service as received in step 3 towards the SMF+PGW-C (or H-SMF+P-GW-C via V-SMF, in the case of roaming scenario) via AMF with an indication that mobility due to fallback for IMS voice is ongoing. The SMF+PGW-C reports the EPS Fallback event to the PCF if the PCF has subscribed to this event.
If NG-RAN responds indicating rejection to set up the QoS flow for IMS voice, steps 5-7 from clause 4.13.6.1 are executed if EPS fallback is triggered, or steps 5-6 from clause 4.13.6.2 are executed if inter-RAT Fallback for IMS voice is triggered. The SMF+PGW-C executes the release of resources in non-3GPP AN as specified in step 3 of clauses 4.11.4.1, 4.9.2.1 and 4.9.2.3.
NOTE 3: The timing of executing the release of resources in non-3GPP AN will depend on whether NG-RAN decides to trigger EPS or inter-RAT fallback but will take place at least after step 5.
If NG-RAN rejects entire PDU session used for IMS voice service, the SMF should stop the ongoing procedure and keep the PDN connection / PDU Session at non-3GPP side. The NG-RAN performs AN release with redirection or handover procedure.
In both cases, after receiving the AN release with redirection or completion of the handover procedure the UE initiates TAU procedure. In the case of inter-system redirection to EPS, if the UE decides to re-initiate handover of an IMS voice session over non-3GPP access to EPS after inter-system change from 5GS to EPS is completed, the UE includes active flag in the request.
NOTE 4: Depending on UE implementation, the UE can re-initiate handover of an IMS voice session over non-3GPP access to EPS if the inter-system change from 5GS to EPS is triggered by the NG-RAN and the UE does not receive a response to the PDU session establishment request i.e. when the establishment of the entire PDU session used for voice is rejected by NG-RAN. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.13.7 MSISDN-less MO SMS | |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.13.7.1 General | The Nnef_MSISDN-less_MO_SMS service is used by the NEF to send the MSISDN-less MO SMS to the AF. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.13.7.2 The procedure of MSISDN-less MO SMS Service | Figure 4.13.7.2-1: MSISDN-less MO SMS procedure via Nnef
1. The UE uses SMS over NAS procedures in clause 4.13.3 to send an SMS to the AF.
The service centre address points to the SMS-SC which contains the function described in this procedure, the destination SME address is set to short/long code of the AF and the Application Port ID element of the TP-User-Data field is set to the appropriate value.
For MSISDN-less subscription, the dummy MSISDN is used. This MSISDN and the IMSI of the UE are sent to SMS-SC.
2. SMS-SC uses the destination SME address (long/short code of the AF) to identify the corresponding NEF based on a pre-configured mapping table. SMS-SC extracts the SMS payload, Application port ID and IMSI of the UE and delivers them to NEF along with the destination SME address (long/short code of the AF). The NEF acts as an MTC-IWF in this procedure.
3. The NEF invokes Nudm_SDM_Get (Identifier Translation, IMSI, Application Port ID, AF Identifier) to resolve the IMSI and Application Port ID to a GPSI (External Id).
4. The UDM provides a Nudm_SDM_Get response (GPSI). If the UE is not allowed to send an SMS payload to this AF, or there is no valid subscription information for this user, the flow proceeds to step 6.
5. The NEF provides a Nnef_MSISDN-less_MO_SMSNotify (SMS payload, GPSI and Application Port ID) message to the AF. The AF is identified with the destination SME address (long/short code of the AF) received from step 2. The payload is delivered directly to the AF, it is not processed by NEF.
6. The NEF, acting as an MTC-IWF, returns a success or failure delivery indication to SMS-SC.
7. SMS-SC indicates success/failure back to UE using existing SMS delivery report defined in TS 23.040 [7]. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.13.8 Support of 5G LAN-type service | |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.13.8.1 Support of 5G VN group management | The information of 5G VN group is provided by the AF to the NEF and is stored in the UDR, by using the NEF service operations information flow procedure described in clause 4.15.6.2. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.13.8.2 Support of 5G VN group communication | |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.13.8.2.1 General | This clause specifies the procedures for 5G VN group communication. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.13.8.2.2 group-level N4 session management procedures | The SMF shall create an group-level N4 session on the UPF for a 5G VN group when N19-based forwarding is applied. The group-level N4 Session management procedures enable the SMF to create, update or delete the group-level N4 Session, e.g. add or delete N4 rules, allocate or release the N19 tunnel resources.
In the case of N19-based forwarding is applied, the followings apply for the PDU Sessions targeting the (DNN, S-NSSAI) associated with a 5G VN group:
- If the PDU Sessions targeting the same 5G VN group are anchored at different UPFs, the SMF shall create the group-level N4 Session in each involved UPF via N4 Session Establishment procedure (clause 4.4.1.2) in order to establish N19 tunnel(s) between the UPFs and install the N4 rules.
- If the last PDU Session for this 5G VN group is released on a UPF, the SMF may delete the group-level N4 Session in the UPF via N4 Session Release procedure (clause 4.4.1.4) and release the N19 tunnel(s) between this UPF and other UPF(s) serving the 5G VN group via update of the corresponding N4 rules.
- If an address of the UE within the 5G VN group is allocated or released, the SMF may update the N4 rules(e.g. PDRs and FARs) related to the UE address into the group-level N4 Session context via N4 Session Modification procedure (clause 4.4.1.3). |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.14 Support for Dual Connectivity | |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.14.1 RAN Initiated QoS Flow Mobility | This procedure is used to transfer QoS Flows to and from Secondary RAN Node. During this procedure, the SMF and UPF are never re-allocated. The UPF referred in this clause 4.14.1 is the UPF which terminates N3 interface in the 5GC. The presence of IP connectivity between the UPF and the Master RAN node, as well as between the UPF and the Secondary RAN node is assumed.
If QoS Flows for multiple PDU Sessions need to be transferred to or from Secondary RAN Node, the procedure shown in the Figure 4.14.1-1 below is repeated for each PDU Session.
Figure 4.14.1-1: NG-RAN initiated QoS Flow mobility procedure
1. The Master RAN node sends a N2 QoS Flow mobility Indication (PDU Session ID, QFI(s), AN Tunnel Info, User Location Information) message to the AMF. AN Tunnel Info includes the new RAN tunnel endpoint for the QFI(s) for which the AN Tunnel Info shall be modified. The User Location Information shall include the serving cell's ID and if Dual Connectivity is activated for the UE, the PSCell ID.
2. AMF to SMF: Nsmf_PDUSession_UpdateSMContext Request (N2 QoS Flow mobility Indication message PDU Session ID).
3. The SMF sends an N4 Session Modification Request (PDU Session ID(s), QFI(s), AN Tunnel Info for downlink user plane) message to the UPF.
4. The UPF returns an N4 Session Modification Response (CN Tunnel Info for uplink traffic) message to the SMF after requested QFIs are switched.
NOTE: Step 7 can occur any time after receipt of N4 Session Modification Response at the SMF.
5. SMF to AMF: Nsmf_PDUSession_UpdateSMContext response (N2 SM information (CN Tunnel Info for uplink traffic)) for QFIs of the PDU Session which have been switched successfully. If none of the requested QFIs have been switched successfully, the SMF shall send an N2 QoS Flow mobility Failure message.
6. In order to assist the reordering function in the Master RAN node and/or Secondary RAN node, for each affected N3 tunnel the UPF sends one or more "end marker" packets on the old tunnel immediately after switching the tunnel for the QFI. The UPF starts sending downlink packets to the Target NG-RAN.
7. The AMF relays message 5 to the Master RAN node. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15 Network Exposure | |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.1 General | The network capability exposure comprises
- Exposure of network events externally as well as internally towards core network NFs;
- Exposure of provisioning capability towards external functions;
- Exposure of policy and charging capabilities towards external functions;
- Exposure of core network internal capabilities for analytics.
- Exposure of analytics to external party.
- Retrieval of data from external party by NWDAF.
- Exposure of number of registered UEs and/or established PDU Sessions for a network slice that is subject to Network Slice Admission Control towards core network NFs or external party.
- Exposure of Member UE selection assistance information including list(s) of candidate UEs based on the UE list provided by the AF and possibly additional information that fulfil some Member UE filtering criteria provided by the AF.
When subscribing to event reporting the NF consumer(s) provide:
- One or multiple Event ID(s). An Event ID identifies the type of event being subscribed to (e.g. PDU Session Release, UE mobility out of an Area of Interest, etc.).
- Event Filter Information: Provides Event Parameter Types and Event Parameter Value(s) to be matched against, in order to meet the condition for notifying the subscribed Event ID e.g. the Event Parameter Type could be "Area of interest" and Event Parameter Value list could be list of TAs; The Event Filter depends on the Event ID. The Event Filter Information is provided per Event ID(s) being subscribed to: within a subscription different Event ID(s) may be associated with different Event Filter Information.
- Event Reporting Information described in the Table 4.15.1-1 below. Within a subscription all Event ID(s) are associated with a unique Event Reporting Information.
- Target of Event Reporting: this may indicate a specific UE or PDU Session, a group of UE(s) or any UE (i.e. all UEs), Within a subscription all Event ID (s) are associated with the same Target of Event Reporting (possibly corresponding to multiple UE or multiple PDU Sessions).
- A Notification Target Address (+ Notification Correlation ID) allowing the Event Receiving NF to correlate notifications received from the Event provider with this subscription. A subscription is associated with an unique Notification Target Address (+ Notification Correlation ID). In the case that the NF consumer subscribes to the NF producer on behalf of other NF, the NF consumer includes the Notification Target Address(+Notification Correlation ID) of other NF for the Event ID which is to be notified to other NF directly and the Notification Target Address(+Notification Correlation ID) of itself for the Subscription change related event notification. Each Notification Target Address(+ Notification Correlation ID) is associated with related (set of) Event ID(s).
- An Expiry time represents the time upto which the subscription is desired to be kept as active. The NF service consumer may suggest an Expiry time and provide to the NF service producer. Based on the operator's policy, the NF service producer decides whether the subscription can be expired. If the subscription can be expired, the NF service producer determines the Expiry time and provide it in the response to the NF service consumer. If the event subscription is about to expire based on the received Expiry time and the NF service consumer wants to keep receiving notifications, the NF service consumer update the subscription with the NF service producer in order to extend the Expiry time. Once the Expiry time associated with the subscription is reached, the subscription becomes invalid at the NF service producer. If the NF service consumer wants to keep receiving notifications, it shall create a new subscription with the NF service producer.
When the subscription is accepted by the Event provider NF, the consumer NF receives from the event provider NF an identifier (Subscription Correlation ID) allowing to further manage (modify, delete) this subscription.
NOTE 1: The Notification Correlation ID is allocated by the consumer NF that subscribes to event reporting and the Subscription Correlation ID is allocated by the NF that notifies when the event is met. Both correlation identifiers can be assigned the same value, although in principle they are supposed to be different, as they are optimized for finding the subscription related context within each NF.
The consumer NF may use an operation dedicated to subscription modification to add or remove Event ID(s) to this subscription or to modify Event Filter Information.
Events are subscribed by the consumer NF(s) by providing Event Filters. The contents of the Event Reporting Information along with the presence requirement of each information element is described in Table 4.15.1-1.
Table 4.15.1-1: Event Reporting Information
Event Reporting Information Parameter
Description
Presence requirement
Event reporting mode
Mode of reporting - e.g. reporting up to a maximum number of reports, periodic reporting along with periodicity, variable reporting periodicity, reporting up to a maximum duration, reporting when threshold is reached.
mandatory
(see NOTE 7)
Maximum number of reports
Maximum number of reports after which the event subscription ceases to exist.
(see NOTE 1)
Maximum duration of reporting
Maximum duration after which the event subscription ceases to exist.
(see NOTE 1)
Immediate reporting flag
The Event provider NF notifies the current status of the subscribed event, if available, immediately to the consumer NF.
Variable reporting periodicity information (0..N)
List of variable measurement information.
(see NOTE 7)
> Reporting periodicity
Reporting periodicity.
(see NOTE 7)
>Condition
The corresponding condition related to Reporting periodicity e.g. load of NF service producer.
(see NOTE 7)
Sampling ratio
Percentage of sampling (1%..100%) among impacted UEs.
optional
(see NOTE 2)
Partitioning criteria
Criteria for partitioning UEs before applying sampling ratio.
optional
(see NOTE 2)
Group Reporting Guard Time
Parameter for group-based monitoring configuration to indicate the time for which the Monitoring Event Reporting(s) related with the UEs in a group can be aggregated before sending them to the consumer NF.
Optional
Deactivate notification flag
Indicates to the Event provider NF that the notification of the available events shall be muted until the Event consumer NF provides the retrieval notification flag to retrieve the events stored.
Optional (see NOTE 8)
Retrieval notification flag
Indicates to the Event provider NF to send the notification to the Event consumer NF with the stored events and mutes again the notification of future events.
Optional (see NOTE 8)
Muting Exception Instructions
Indicates to an Event provider NF instructions for the subscription and stored events when an exception (e.g. full buffer) occurs at the Event provider.
Optional
(see NOTE 6 and NOTE 8)
Granularity of dynamics
The maximum amount of dynamics in the event which allows to skip an event notification.
optional
(see NOTE 3)
Reporting type
Event provider NF reports only when the events differs from the previously notified event.
optional
(see NOTE 4)
Reporting Threshold
Threshold values indicate conditions on the level to be reached for the reporting.
Optional
(see NOTE 5)
NOTE 1: The requester shall include 2) Maximum number of reports or 3) Maximum duration of reporting, or both, depending on 1) Event reporting mode.
NOTE 2: Parameter only applicable to certain event IDs reporting metrics (e.g. Number of UEs present in a geographical area) used and used e.g. by the NWDAF for data collection.
NOTE 3: The Granularity of dynamics includes 1) the range of scalar value, 2) the list of events identification, or 3) the previous notification. The range of scalar value is only applicable to the event depicted as number (e.g. the number of UE), the others is applicable to the event depicted as identification (e.g. UE location, UE identification).
NOTE 4: The differences in event includes the events have been newly appeared, disappeared and changed from the previous notification.
NOTE 5: This parameter is included only if the Event reporting mode indicates reporting when threshold is reached.
NOTE 6: This parameter is included only if the "Deactivate notification flag" is set.
NOTE 7: If the requester includes "variable reporting periodicity", then reporting periodicity changes depending on e.g. load of NF service producer; otherwise the reporting periodicity is fixed.
NOTE 8: The support of this parameter is only required for services where NWDAF and/or DCCF are among the example consumers. It is expected that this parameter is used only if the Event Consumer NF is NWDAF or DCCF.
NOTE 2: Explicit unsubscribe by the NF consumer is still possible.
Maximum number of reports is applicable to the subscription to one UE or a group of UE(s). When the subscription is applied to a group of UE(s), the initial value of the parameter is applied to each individual member UE. The count of number of reports is per UE and per Event Type granularity also for group member UE.
Maximum duration of reporting is applicable to the subscription to one UE, a group of UE(s) or any UE. When the subscription is applied to a group of UE(s), this parameter applies to each group member UE. When the subscription is applied to any UE, this parameter applies to all the impacted UEs.
If for a given subscription Maximum duration of reporting is included then the subscription is cancelled locally in the NF as soon as Maximum duration of reporting is reached. If the Maximum number of reports is reached for a given subscription, the NEF cancels the subscription in the affected NFs. If both Maximum Number of reports and Maximum duration of reporting are included then the subscription expires or is cancelled as soon as one of the conditions is met.
Sampling ratio is applicable to subscription targeting a group of UEs or any UE. When a sampling ratio is provided, a random subset is selected among the target UEs according to the sampling ratio and only the events related to this subset are reported. A UE remains selected until it is no longer managed by the event provider NF. A UE newly managed by the NF may be selected.
Partitioning criteria are applicable to subscription targeting a group of UEs or any UE and may be used when sampling ratio is used. These criteria are used to instruct the NF on how to group the UEs before applying the sampling ratio. When partitioning criteria are provided, the NF groups the targeted UEs (i.e. creates sub-populations/strata) based on the partition criteria parameter. Then, from each sub-population/stratum, the NF selects a subset of UEs by sampling randomly from each sub-population according to the sampling ratio. For a given type of partitioning criteria, the UE belongs to a single sub-population/stratum as long as it is served by the NF. The types of Partitioning Criteria are described in Table 4.15.1-2:
Table 4.15.1-2: Types of Partitioning Criteria
Types of Partitioning Criteria
Type Allocation Code
Subscriber PLMN ID
Geographical area, i.e. list(s) of TAI(s)
S-NSSAI
DNN
Group Reporting Guard Time is an optional parameter for group-based monitoring configuration to indicate the time for which the Monitoring Event Reporting(s) related with the UEs in a group can be aggregated before sending them to the consumer NF. The value of the Group Reporting Guard time should be set less than the Maximum duration of reporting. For the continuous monitoring reporting, unless the Maximum duration of reporting has been reached, the Group Reporting Guard timer is restarted when it expires. If the time left until the Maximum duration of reporting is less than the Group Reporting Guard Time, then the Group Reporting Guard timer shall be set to expire when the Maximum duration of reporting expires. If the Maximum duration of reporting is expired, the Group Reporting Guard Time, if running, shall be considered to expire and aggregated Monitoring Event Reporting(s) is sent to destination immediately.
Deactivation notification flag and retrieval notification flag enable the mute storage of events for a limited size of events at the Event provider NF, thus reducing the number of notifications and the overall signalling between the Event provider NF and the Event consumer NF. Usage of these parameters is further specified in clause 6.2.7 of TS 23.288 [50].
Muting Exception Instructions specify actions to be taken by the Event provider NF if the Deactivation notification flag is set and an exception occurs at the Event Producer NF (e.g. the Event provider can no longer buffer notifications because storage space is no longer available). The actions are specified in clause 6.2.7 of TS 23.288 [50].
Granularity of dynamics indicates negligible changes in the target event of the subscription for which notification is not required. The changes in the Granularity of dynamics are depicted as the range of scalar value (x, y) where it means [the previously notified scalar value - x, the previously notified scalar value + y), the list of event identification(s) (e.g. list of SUPI(s)), or the previous notification. If the Granularity of dynamics is provided, the provider NF shall send the notification only when the changes in the target event are not described in the Granularity of dynamics, except for the first notification.
Reporting type is a parameter to reduce the data volume of notification. If the Reporting type is provided, the provider NF shall notify the events that have been newly appeared, disappeared and changed compared to the previous notification, except for the first notification.
Table 4.15.1-1 indicates the presence requirements for the Event Reporting Information.
Corresponding notifications contain at least the Notification Correlation ID together with the Event ID and the individual target (e.g. UE or PDU Session ID) associated with the notification.
If the NF service consumer decides to terminate the event subscription, it unsubscribes the event subscription by sending an unsubscribe request to the event provider NF. After receiving an unsubscribe request from the NF service consumer, the event provider NF terminates the event subscription.
If the NF service consumer has subscribed to group-based monitoring, then the NF service consumer may subsequently unsubscribe to the whole group or one or more identified group member UEs. Such partial cancellation of group-based monitoring does not affect the other group member UEs, but it only cancels the monitoring event subscription for the identified group member UEs. Partial cancellation of group-based monitoring can be caused by the following reasons:
- UE's subscription is discontinued in the UDM;
- UE's authorisation to the subscribed event type is revoked;
- The subscribing NF explicitly unsubscribes to monitoring of selected UE(s); or
- UE is removed from the monitoring target group that was identified in monitoring subscription.
If the NF service consumer has subscribed to group-based monitoring and later new group member UEs are added to the group, then the NF service consumer may also subsequently add monitoring event subscription for the new group member UEs.
The following clauses describe the external exposure of network capabilities and core network internal event and capability exposure.
When the immediate reporting flag is set, the first corresponding event report is included in the subscription response message, if corresponding information is available at the reception of the subscription request of the event.
During Monitoring Event Subscription as in clause 4.15.3, Parameter Provisioning as in clause 4.15.6, NIDD configuration as in clause 4.25.3 and Enhanced Coverage Restriction Control as in clause 4.27.1, the optional parameter MTC Provider Information is a reference parameter that may be provided by AF or determined by NEF based on which AF it communicates with. The MTC Provider Information identifies the MTC Service Provider and/or MTC Application.
NOTE 3: The MTC Provider Information can be used by Service Providers for, e.g. to distinguish their different customers.
NOTE 4: The MTC Provider Information is an optional parameter. The NEF can validate the provided MTC Provider Information and override it to a NEF selected MTC Provider Information based on configuration. How the NEF determines the MTC Provider Information, if not present, is left to implementation (e.g. based on the requesting AF). |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.2 External Exposure of Network Capabilities | The Network Exposure Function (NEF) supports external exposure of capabilities of network functions. External exposure can be categorized as Monitoring capability, Provisioning capability, Policy/Charging capability, network status reporting capability, Analytics reporting capability and Member UE selection assistance capability. The Monitoring capability is for monitoring of specific event for UE in 5GS and making such monitoring events information available for external exposure via the NEF. The Provisioning capability is for allowing external party to provision of information which can be used for the UE in 5GS. The Policy/Charging capability is for handling QoS and charging policy for the UE based on the request from external party. The Analytics capability is for allowing external party to acquire analytics information generated by 5G System. The Member UE selection assistance capability enables the NEF to consolidate information collected from other 5GC NFs, which fulfil the Member UE filtering criteria requested by the AF, to derive one or more lists of UE(s) and possibly additional information that assists AF for the selection of candidate members to participate in the application layer operation e.g. federated learning operation in the application layer.
The details for the External Exposure of Analytics capabilities as well as interactions between NEF, external party and NWDAF are described in TS 23.288 [50].
4.15.2a Data Collection from an AF
The Network Exposure Function (NEF) supports the capability to collect data from an AF as specified in TS 23.501 [2]. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.3 Event Exposure using NEF | |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.3.1 Monitoring Events | The Monitoring Events feature is intended for monitoring of specific events in 3GPP system and making such monitoring events information reported via the NEF. It is comprised of means that allow NFs in 5GS for configuring the specific events, the event detection and the event reporting to the requested party.
To support monitoring features in roaming scenarios, a roaming agreement needs to be made between the HPLMN and the VPLMN. If the AMF/SMF in the VPLMN determine that normalisation of an event report is required, the AMF/SMF normalises the event report before sending it to the NEF.
The set of capabilities required for monitoring shall be accessible via NEF to NFs in 5GS. Monitoring Events via the UDM, the AMF, the SMF, the NSACF and the GMLC enables NEF to configure a given Monitor Event at UDM, AMF, SMF, NSACF or GMLC and reporting of the event via UDM and/or AMF, SMF, NSACF or GMLC. Depending on the specific monitoring event or information, it is the AMF, GMLC, NSACF or the UDM that is aware of the monitoring event or information and makes it reported via the NEF.
The following table enumerates the monitoring events and their detection criteria:
Table 4.15.3.1-1: List of events for monitoring capability
Event
Detection criteria
Which NF detects the event
Loss of Connectivity
Network detects that the UE is no longer reachable for either signalling or user plane communication (see NOTE 4).
The AF may provide a Maximum Detection Time, which indicates the maximum period of time without any communication with the UE after which the AF is to be informed that the UE is considered to be unreachable (see NOTE 7).
If Unavailability Period Duration has been provided by the UE, the AMF uses the remaining value of it to determine the foreseen Loss of Connectivity time as described in clause 5.4.1.4 of TS 23.501 [2].
AMF
UE reachability
Detected when the UE transitions to CM-CONNECTED state or when the UE will become reachable for paging, e.g. Periodic Registration Update timer. It indicates when the UE becomes reachable for sending downlink data to the UE.
The AF may provide the following parameters:
1) Maximum Latency;
2) Maximum Response Time;
3) Suggested number of downlink packets. (see NOTE 5 and NOTE 7).
This event requires the Reachability Filter set to UE reachable for DL traffic" (see clause 5.2.2.3.1-1). For the usage of this event, see clauses 4.2.5.2 and 4.2.5.3.
When requesting UE reachability monitoring, the AF may in addition request Idle Status Indication to be included in the UE reachability event reporting.
AMF, UDM
Location Reporting
This event is detected based on the Event Reporting Information Parameters that were received in the Monitoring Request (one-time reporting, maximum number of reports, maximum duration of reporting, periodicity, etc. as specified in clause 4.15.1).
It reports either the Current Location or the Last Known Location of a UE.
When AMF is the detecting NF:
One-time and Continuous Location Reporting are supported. For Continuous Location Reporting the serving node(s) sends a notification every time it becomes aware of a location change, with the granularity depending on the accepted accuracy of location (see NOTE 1).
For One-time Reporting with immediate reporting flag set, AMF reports the Last Known Location immediately.
When AMF is the detecting NF:
If the immediate reporting flag is not set, the AMF reports the UE Current Location (In case the AMF does not have the UE current location in the granularity as requested by the location report, the AMF retrieves the information via NG-RAN Location reporting procedure as defined in clause 4.10).
When GMLC is the detecting NF:
Immediate and Deferred Location Reporting is supported. For Deferred Location Reporting the event types UE availability, Area, Periodic Location and Motion are supported.
AMF, GMLC
Change of SUPI-PEI association
This event is detected when the association between PEI and subscription (SUPI) changes (USIM change).
UDM
Roaming status
This event is detected based on the UE's current roaming status (the serving PLMN and/or whether the UE is in its HPLMN) and notification is sent when that status changes. (see NOTE 2).
If the UE is registered via both 3GPP and N3GPP Access Type, then both instances of Roaming status are included.
UDM
Communication failure
This event is detected when RAN or NAS level failure is detected based on connection release and it identifies RAN/NAS release code.
AMF
Availability after Downlink Data Notification failure
This event is detected when the UE becomes reachable again after downlink data delivery failure.
When requesting Availability after Downlink Data Notification failure monitoring, the AF may in addition request Idle Status Indication to be included in the UE reachability event reporting.
AMF
PDU Session Status
This event is detected when PDU session is established or released. (see NOTE 6)
SMF
Number of UEs present in a geographical area
This event is detected based on the Event Reporting Information Parameters that were received in the Monitoring Request (Level of aggregation, Sampling ratio, see clause 4.15.1).
It indicates the number of UEs that are in the geographical area described by the AF. The AF may ask for the UEs that the system knows by its normal operation to be within the area (Last Known Location) or the AF may request the system to also actively look for the UEs within the area (Current Location).
AMF
CN Type change
The event is detected when the UE moves between EPC and 5GC. It indicates the current CN type for a UE or a group of UEs when detecting that the UE switches between being served by a MME and an AMF or when accepting the event subscription. (see NOTE 3)
UDM
Downlink data delivery status
It indicates the downlink data delivery status in the core network. Events are reported at the first occurrence of packets being buffered, transmitted or discarded, including:
- Downlink data in extended buffering, including:
- First data packet buffered event
- Estimated buffering time, as per clause 4.2.3.3
- First downlink data transmitted event
- First downlink data discarded event
SMF
UE reachability for SMS delivery
For SMS over NAS, this event is detected when an SMSF is registered for a UE and the UE is reachable as determined by the AMF and the UDM.
For SMS over IP, the event is detected when the UE is reachable as determined by the AMF and the UDM regardless of an SMSF being registered.
This enables the UE to receive an SMS. See clauses 4.2.5.2 and 4.2.5.3 (see NOTE 8).
UDM
UE memory available for SMS
This event is detected when the UDM receives UE memory available for SMS indication from the SMSF as part of Alert procedure as specified in clause 5.1.8 of TS 23.540 [84]
UDM
Number of registered UEs or established PDU Sessions
It indicates the current number of registered UEs or established PDU Sessions for a network slice that is subject to NSAC.
For One-time Reporting with Immediate Reporting Flag set, NSACF reports the number of registered UEs or established PDU Sessions immediately.
NSACF
Area Of Interest
It indicates change of the UE presence in the Area Of Interest.
AMF, GMLC
Group Member List Change
It indicates the changes on the members of the group.
This event apply to a group of UEs (identified by an External Group ID), such as 5G VN group (see NOTE 9) or other groups.
UDM
Session inactivity time
This event is detected by the SMF when the PDU Session has no data transfer for a period specified by the Inactivity Timer. via the User plane status information event, see clause 5.2.8.3.1.
SMF
Traffic volume
This event measures the traffic volume (UL and DL) aggregated for the PDU Session (NOTE 10).
UPF
UL/DL data rate
This event measures the data rate (UL and DL) aggregated for the PDU Session (NOTE 10).
UPF
Application Detection
Detection of application start or stop
(See NOTE 11), as described in clause 6.1.3.18 of TS 23.503 [20].
PCF
Energy Consumption
This event provides exposure of energy consumption information as required granularities (UE, PDU Session and/or QoS flow) as described in clause 5.51.2.4 of TS 23.501 [2]
EIF
NOTE 1: Location granularity for event request, or event report, or both could be at cell level (Cell ID) or TA level. The granularity can also be expressed by other formats such as geodetic uncertainty shapes (e.g. polygons, circles, etc.) or civic addresses (e.g. streets, districts, etc.) which can be mapped by NEF to AMF specific granularity levels.
NOTE 2: Roaming status means whether the UE is in HPLMN or VPLMN based on the most recently received registration state in the UDM. The following parameters may be included as part of event report:
1) Equipment identifier (PEI).
2) Subscription identifiers (e.g. GPSI).
This event can be used by AF to implement certain capabilities, for e.g. send welcome SMS to subscriber, etc.
NOTE 3: CN type of CN Type change event is defined in clause 5.17.5.1 of TS 23.501 [2].
NOTE 4: In the case of UDM service operation information flow, the UDM should set the subscribed periodic registration timer to a smaller value than the value of Maximum Detection Time, since the value of the mobile reachable timer is larger than the value of the periodic registration timer.
NOTE 5: Maximum Latency, Maximum Response Time and Suggested number of downlink packets are defined in clause 4.15.6.3a.
NOTE 6: The NEF makes a mapping between the 5GS internal event "PDU Session Status" and the T8 API event "PDN Connectivity Status".
NOTE 7: The preferred method for provisioning Network Configuration Parameters is External Parameter Provisioning specified in clause 4.15.6.3a. Provisioning event specific parameters as part of Monitoring Request is expected to be used only by the AF that does not support Parameter Provisioning procedure specified in clause 4.15.6.3a.
NOTE 8: The NEF maps between the T8 API event "UE reachability" with reachability type SMS and the 5GS internal event "UE reachability for SMS delivery" for SMS over NAS.
The event "UE reachability for SMS delivery" for SMS over IP is used by HSS as described in clause 5.5.6.3 of TS 23.632 [68].
NOTE 9: 5G VN group management is defined in the clause 5.29.2 of TS 23.501 [2].
NOTE 10: NEF subscribes to the UPF event applicable for a PDU session via SMF and the result is exposed to NEF by UPF directly. The corresponding procedure for NEF to trigger the UPF event can be found in clause 4.15.3.2.3.
NOTE 11: This event uses bulk subscription/notification, which may impact the PCF/SMF/UPF performance. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.3.2 Information flows | |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.3.2.1 AMF service operations information flow | The procedure is used by the NF to subscribe to notifications and to explicitly cancel a previous subscription. Cancelling is done by sending Namf_EventExposure_UnSubscribe request identifying Subscription Correlation ID. The notification steps 3 and 4 are not applicable in cancellation case.
Figure 4.15.3.2.1-1: Namf_EventExposure_Subscribe, Unsubscribe and Notify operations
1. A NEF sends a request to subscribe to a (set of) Event ID(s) in AMF in Namf_EventExposure_Subscribe request. The NEF could be the same NF subscribing to receive the event notification reports (i.e. Event Receiving NF) or it could be a different NF. The NEF subscribes to one or several Event(s) (identified by Event ID) and provides the associated notification endpoint of the Event Receiving NF. If the NEF itself is not the Event Receiving NF, the NEF shall additionally provide the notification endpoint of itself besides the notification endpoint of Event Receiving NF. Each notification endpoint is associated with the related (set of) Event ID(s). This is to assure the NEF can receive the notification of subscription change related event (e.g. Subscription Correlation ID Change).
Event Reporting information defines the type of reporting requested. If the reporting event subscription is authorized by the AMF, the AMF records the association of the event trigger and the requester identity.
2. AMF acknowledges the execution of Namf_EventExposure_Subscribe.
3. [Conditional - depending on the Event] The AMF detects the monitored event occurs and sends the event report by means of Namf_EventExposure_Notify message, to the notification endpoint of the Event Receiving NF.
4. [Conditional- depending on the Event] The AMF detects the subscription change related event occurs, e.g. Subscription Correlation ID change due to AMF reallocation, it sends the event report by means of Namf_EventExposure_Notify message to the NEF. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.3.2.2 UDM service operations information flow | The procedure is used by the NEF to subscribe to event notifications, to modify group-based subscriptions to event notifications, including removal or addition of certain UEs in a UE group and to explicitly cancel a previous subscription (see clause 4.15.1). Cancelling is done by sending Nudm_EventExposure_Unsubscribe request identifying the subscription to cancel. The notification steps 4 and 5 are not applicable in cancellation case.
Figure 4.15.3.2.2-1: Nudm_EventExposure_Subscribe, Unsubscribe and Notify operations
1. The NEF subscribes to one or several monitoring events by sending Nudm_EventExposure_Subscribe request. The NEF subscribes to one or several Event(s) (identified by Event ID) and provides the associated notification endpoint of the NEF.
Event Reporting Information defines the type of reporting requested. If the reporting event subscription is authorized by the UDM, the UDM records the association of the event trigger and the requester identity.
The subscription may include Maximum number of reports and/or Maximum duration of reporting IE and optionally MTC Provider Information.
If subscription to group-based event notifications are removed for certain UEs in a group of UEs for which there is an event notification subscription, the NEF provides impacted UE information (e.g. SUPI, MSISDN or External Identity) and operation indication (cancellation) to UDM via Nudm_EventExposure_Subscribe without cancelling the entire group-based event notification subscription. If the Maximum Number of Reports applies to the event subscription, the NEF sets the stored number of reports of the indicated UE(s) to Maximum Number of Reports.
If subscription to group-based event notifications are added for certain UEs in a group of UEs for which there is an event notification subscription, the NEF provides impacted UE information (e.g. SUPI, MSISDN or External Identity) and operation indication (addition) to UDM via Nudm_EventExposure_Subscribe.
2a. [Conditional] Some events, require that UDM sends Namf_EventExposure_Subscribe request to the AMF serving that UE. As the UDM itself is not the Event Receiving NF, the UDM shall additionally provide the notification endpoint of itself besides the notification endpoint of NEF. Each notification endpoint is associated with the related (set of) Event ID(s). This is to assure the UDM can receive the notification of subscription change related event.
The UDM sends the Namf_EventExposure_Subscribe request to all serving AMF(s) (if subscription applies to a UE or a group of UE(s)), or to all the AMF(s) in the same PLMN as UDM (if subscription applies to any UE). The UDM stores the subscription even if the target UE or group member UE is not registered at the time of subscription.
NOTE 1: If the single target UE, or group member UE, registers later on with an AMF which does not have event subscription or group event subscription(s) for that UE or UE group, then the UDM creates subscriptions to those event(s) with the AMF during the Registration procedure as specified in clause 4.2.2.2.2.
If the subscription applies to a group of UE(s), the UDM shall include the same notification endpoint of itself, i.e. Notification Target Address (+ Notification Correlation Id), in the subscriptions to all UE's serving AMF(s).
NOTE 2: The same notification endpoint of UDM is to help the AMF identify whether the subscription for the requested group event is same or not when a new group member UE is registered.
If Nudm_EventExposure_Subscribe with update is received in step 1 indicating removal of event notification subscription for certain UEs in a group of UEs for which there is an event notification subscription, the UDM provides impacted UE information (e.g. SUPI, MSISDN) and operation indication (cancellation) to AMF via Namf_EventExposure_Subscribe without cancelling the entire group-based event notification subscription, for the event monitored by AMF.
If Nudm_EventExposure_Subscribe with update is received in step 1 indicating addition of event notification subscription for certain UEs in a group of UEs for which there is an event notification subscription, the UDM provides impacted UE information (e.g. SUPI, MSISDN) and operation indication (addition) to AMF via Namf_EventExposure_Subscribe for the event monitored by AMF.
2b. [Conditional] AMF acknowledges the execution of Namf_EventExposure_Subscribe.
3. UDM acknowledges the execution of Nudm_EventExposure_Subscribe.
If the subscription is applicable to a group of UE(s) and the Maximum number of reports is included in the Event Report information in step 1, the Number of UEs (including all group member UEs irrespective of their registration state) within this group is included in the acknowledgement. If AMF provides the first event report in step 2b, the UDM includes the event report in the acknowledgement.
4a - 4b. [Conditional - depending on the Event] The UDM detects the monitored event occurs and sends the event report, by means of Nudm_EventExposure_Notify message, to the associated notification endpoint of the NEF, along with the time stamp. NEF may store the information in the UDR along with the time stamp using either Nudr_DM_Create or Nudr_DM_Update service operation as appropriate.
If Nudm_EventExposure_Subscribe with update is received in step 1 indicating removal of event notification subscription for certain UEs in a group of UEs for which there is an event notification subscription, the UDM shall stop the event notification for the impacted UEs. If Maximum number of Reports is applied, the UDM shall set the number of reports of the indicated UE(s) to Maximum Number of Reports for the events monitored by UDM.
If Nudm_EventExposure_Subscribe with update is received in step 1 indicating addition of event notification subscription for certain UEs in a group of UEs for which there is an event notification subscription, the UDM shall create subscription to the event notification for the impacted UEs so as to detect the monitored event and send the event report for such impacted UEs.
4c - 4d. [Conditional - depending on the Event] The AMF detects the monitored event occurs and sends the event report, by means of Namf_EventExposure_Notify message, to the associated notification endpoint of the NEF, along with the time stamp. NEF may store the information in the UDR along with the time stamp using either Nudr_DM_Create or Nudr_DM_Update service operation as appropriate.
If the AMF has a maximum number of reports stored for the UE, the AMF shall decrease its value by one for the reported event.
If Namf_EventExposure_Subscribe with update is received in step 2a indicating removal of event notification subscription for certain UEs in a group of UEs for which there is an event notification subscription, the AMF shall stop the event notifications for the impacted UEs. If Maximum number of Reports is applied, the AMF shall set the number of reports of the indicated UE(s) to Maximum Number of Reports.
If Namf_EventExposure_Subscribe with update is received in step 2a indicating addition of event notification subscription for certain UEs in a group of UEs for which there is an event notification subscription, the AMF shall create subscription to the event notification for the impacted UEs so as to detect the monitored event and send the event report for such impacted UEs.
For both step 4a and step 4c, when the maximum number of reports is reached and if the subscription is applied to a UE, The NEF unsubscribes the monitoring event(s) to the UDM and the UDM unsubscribes the monitoring event(s) to AMF serving that UE.
For both step 4a and step 4c, when the maximum number of reports is reached for an individual group member UE, the NEF uses the Number of UEs received in step 3 and the Maximum number of reports to determine if reporting for the group is complete. If the NEF determines that reporting for the group is complete, the NEF unsubscribes the monitoring event(s) to the UDM and the UDM unsubscribes the monitoring event(s) to all AMF(s) serving the UEs belonging to that group.
NOTE 3: If an expiry time as specified in clause 6.2.6.2.6 of TS 29.518 [18] is not included in the event subscription, then the life time of the event subscription needs to be controlled by other means as there is no time based cancellation at all even if any group member UEs fail to register.
When the Maximum duration of reporting expires in the NEF, the UDM and the AMF, then each of these nodes shall locally unsubscribe the monitoring event.
5. [Conditional - depending on the Event] The AMF detects the subscription change related event occurs, e.g. Subscription Correlation ID change due to AMF reallocation or addition of new Subscription Correlation ID due to a new group UE registered, it sends the event report by means of Namf_EventExposure_Notify message to the associated notification endpoint of the UDM. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.3.2.3 NEF service operations information flow | The procedure is used by the AF to subscribe to event notifications, to modify group-based subscriptions to event notification and to explicitly cancel a previous subscription (see clause 4.15.1). Cancelling is done by sending Nnef_EventExposure_Unsubscribe request identifying the subscription to cancel with Subscription Correlation ID. The notification steps 6 to 8 are not applicable in cancellation case.
Figure 4.15.3.2.3-1: Nnef_EventExposure_Subscribe, Unsubscribe and Notify operations
1. The AF subscribes to one or several Event(s) (identified by Event ID) and provides the associated notification endpoint of the AF by sending Nnef_EventExposure_Subscribe request.
Event Reporting Information defines the type of reporting requested (e.g. one-time reporting, periodic reporting or event based reporting, for Monitoring Events). If the reporting event subscription is authorized by the NEF, the NEF records the association of the event trigger and the requester identity. The subscription may also include Maximum number of reports and/or Maximum duration of reporting IE and optionally MTC Provider Information.
If subscription to group-based event notifications are removed or added for certain UEs in a group of UEs for which there is an event notification subscription, the AF provides impacted UE information (e.g. SUPI, MSISDN or External Identity) with operation indication which is either cancellation or addition to NEF via Nnef_EventExposure_Subscribe without cancelling the entire group-based event notification subscription.
2. [Conditional - depending on authorization in step 1] The NEF subscribes to received Event(s) (identified by Event ID) and provides the associated notification endpoint of the NEF to UDM by sending Nudm_EventExposure_Subscribe request. The NEF may either receive DNN, S-NSSAI from AF in step 1 or maps the AF-Identifier into DNN and S-NSSAI combination based on local configuration and include DNN, S-NSSAI in the request.
If the reporting event subscription is authorized by the UDM, the UDM records the association of the event trigger and the requester identity. Otherwise, the UDM continues in step 4 indicating failure.
If Nnef_EventExposure_Subscribe with update is received in step 1 indicating removal of event notification subscription for certain UEs in a group of UEs for which there is an event notification subscription, the NEF provides impacted UE information (e.g. SUPI, MSISDN or External Identity) with operation indication (cancellation) to UDM via Nudm_EventExposure_Subscribe without cancelling the entire group-based event notification subscription. If the Maximum Number of Reports applies to the event subscription, the NEF sets the stored number of reports of the indicated UE(s) to Maximum Number of Reports.
If Nnef_EventExposure_Subscribe with update is received in step 1 indicating addition of event notification subscription for certain UEs in a group of UEs for which there is an event notification subscription, the NEF provides impacted UE information (e.g. SUPI, MSISDN or External Identity) with operation indication (addition) to UDM via Nudm_EventExposure_Subscribe.
3a. [Conditional] If the requested event (e.g. monitoring of Loss of Connectivity) requires AMF assistance, then the UDM sends the Namf_EventExposure_Subscribe to the AMF serving the requested user. The UDM sends the Namf_EventExposure_Subscribe request to the all serving AMF(s) (if subscription applies to a UE or a group of UE(s)), or all the AMF in the same PLMN as the UDM (if subscription applies to any UE).
NOTE 1: If the UE, which is a member of a group, registers with an AMF which does not have group event subscription(s) for that group, then the UDM creates subscriptions to those event(s) with the AMF during the Registration procedure in clause 4.2.2.2.2.
As the UDM itself is not the Event Receiving NF, the UDM shall additionally provide the notification endpoint of itself besides the notification endpoint of NEF. Each notification endpoint is associated with the related (set of) Event ID(s). This is to assure the UDM can receive the notification of subscription change related event.
If the subscription applies to a group of UE(s), the UDM shall include the same notification endpoint of itself, i.e. Notification Target Address (+ Notification Correlation Id), in the subscriptions to all UE's serving AMF(s).
NOTE 2: The same notification endpoint of UDM is to help the AMF identify whether the subscription for the requested group event is same or not when a new group member UE is registered.
If Nudm_EventExposure_Subscribe with update is received in step 2 indicating removal of event notification subscription for certain UEs in a group of UEs for which there is an event notification subscription, the UDM provides impacted UE information (e.g. SUPI, MSISDN) with operation indication (cancellation) to AMF via Namf_EventExposure_Subscribe without cancelling the entire group-based event notification subscription, for the event monitored by AMF.
If Nudm_EventExposure_Subscribe with update is received in step 2 indicating addition of event notification subscription for certain UEs in a group of UEs for which there is an event notification subscription, the UDM provides impacted UE information (e.g. SUPI, MSISDN) with operation indication (addition) to AMF via Namf_EventExposure_Subscribe for the event monitored by AMF.
3b. [Conditional] AMF acknowledges the execution of Namf_EventExposure_Subscribe.
3c. [Conditional] If the requested event (e.g. PDU Session Status) requires SMF assistance, then the UDM sends the Nsmf_EventExposure_Subscribe Request message to each SMF where at least one UE identified in step 2 has a PDU session established. The NEF notification endpoint received in step 2 is included in the message.
NOTE 3: In the home routed case, the UDM sends the subscription to the V-SMF via the H-SMF.
3d-e. [Conditional] If the requested event is a UPF event, the SMF instructs the UPF to provide the necessary information. Depending on the event (as specified in clause 4.15.4), the SMF uses either N4 Session Modification signalling (step 3d) or Nupf_EventExposure_Subscribe service operation (step 3e). The SMF sends the request to the UPF including the NEF notification endpoint received in step 3c.
3f. [Conditional] The SMF acknowledges the execution of Nsmf_EventExposure_Subscribe.
4. [Conditional] UDM acknowledges the execution of Nudm_EventExposure_Subscribe.
If the subscription is applicable to a group of UE(s) and the Maximum number of reports is included in the Event Report information in step 1, the Number of UEs (including all group member UEs irrespective of their registration state) is included in the acknowledgement. If AMF or SMF provides the first event report in step 3b or step 3d, the UDM includes the event report in the acknowledgement.
5. NEF acknowledges the execution of Nnef_EventExposure_Subscribe to the requester that initiated the request. If the NEF has received the first event report already in step 4, the NEF includes the event report in the acknowledgement.
6a - 6b. [Conditional - depending on the Event] The UDM (depending on the Event) detects the event occurs and sends the event report, by means of Nudm_EventExposure_Notify message to the associated notification endpoint of the NEF along with the time stamp. NEF may store the information in the UDR along with the time stamp using either Nudr_DM_Create or Nudr_DM_Update service operation as appropriate.
If Nudm_EventExposure_Subscribe with update is received in step 2 indicating removal of event notification subscription for certain UEs in a group of UEs for which there is an event notification subscription, the UDM shall stop the event notification for the impacted UEs. If Maximum number of Reports is applied, the UDM shall set the number of reports of the indicated UE(s) to Maximum Number of Reports for the events monitored by UDM.
If Nudm_EventExposure_Subscribe with update is received in step 2 indicating addition of event notification subscription for certain UEs in a group of UEs for which there is an event notification subscription, the UDM shall create subscription to the event notification for the impacted UEs so as to detect the monitored event and send the event report for such impacted UEs.
6c - 6d. [Conditional - depending on the Event] The AMF detects the event occurs and sends the event report, by means of Namf_EventExposure_Notify message to associated notification endpoint of the NEF along with the time stamp. NEF may store the information in the UDR along with the time stamp using either Nudr_DM_Create or Nudr_DM_Update service operation as appropriate.
If the AMF has a maximum number of reports stored for the UE or the individual member UE, the AMF shall decrease its value by one for the reported event.
If Namf_EventExposure_Subscribe with update is received in step 3a indicating removal of event notification subscription for certain UEs in a group of UEs for which there is an event notification subscription, the AMF shall stop the event notification for the impacted UEs. If Maximum number of Reports is applied, the AMF shall set the number of reports of the indicated UE(s) to Maximum Number of Reports.
If Namf_EventExposure_Subscribe with update is received in step 3a indicating addition of event notification subscription for certain UEs in a group of UEs for which there is an event notification subscription, the AMF shall create subscription to the event notification for the impacted UEs so as to detect the monitored event and send the event report for such impacted UEs.
For both step 6a and step 6c, when the maximum number of reports is reached and if the subscription is applied to a UE, The NEF unsubscribes the monitoring event(s) to the UDM and the UDM unsubscribes the monitoring event(s) to AMF serving for that UE.
For both step 6a and step 6c, when the maximum number of reports is reached for an individual group member UE, the NEF uses the Number of UEs received in step 4 and the Maximum number of reports to determine if reporting for the group is complete. If the NEF determines that reporting for the group is complete, the NEF unsubscribes the monitoring event(s) to the UDM and the UDM unsubscribes the monitoring event(s) to all AMF(s) serving the UEs belonging to that group.
NOTE 4: If an expiry time as specified in clause 6.2.6.2.6 of TS 29.518 [18] is not included in the event subscription, then the life time of the event subscription needs to be controlled by other means as there is no time based cancellation at all even if any group member UEs fail to register.
When the Maximum duration of reporting expires in the NEF, the UDM and the AMF, then each of these nodes shall locally unsubscribe the monitoring event.
6e - 6f. [Conditional - depending on the Event] When the SMF detects a subscribed event, the SMF sends the event report, by means of Nsmf_EventExposure_Notify message, to the associated notification endpoint of the NEF provided in step 3c. NEF may store the information in the UDR along with the time stamp using either Nudr_DM_Create or Nudr_DM_Update service operation as appropriate.
6g - 6h. [Conditional - depending on the Event] When the UPF detects a subscribed event, the UPF sends the event report, by means of Nupf_EventExposure_Notify message, to the associated notification endpoint of the NEF provided by the SMF to UPF as part of step 3c. The NEF may store the information in the UDR along with the time stamp using either Nudr_DM_Create or Nudr_DM_Update service operation as appropriate.
7. [Conditional - depending on the Event in steps 6a-6f] The NEF forwards to the AF the reporting event received by either Nudm_EventExposure_Notify and/or Namf_EventExposure_Notify. In the case of the PDU Session Status event, the NEF maps it to an PDN Connectivity Status notification when reporting to the AF.
8. [Conditional - depending on the Event] The AMF detects the subscription change related event occurs, e.g. Subscription Correlation ID change due to AMF reallocation or addition of new Subscription Correlation ID due to a new group UE registered, it sends the event report, by means of Namf_EventExposure_Notify message to the associated notification endpoint of the UDM.
4.15.3.2.3a Void
4.15.3.2.3b Specific NEF service operations information flow for loss of connectivity and UE reachability
The procedure is used by the AF to subscribe to notifications and to explicitly cancel a previous subscription for loss of connectivity and UE reachability.
Figure 4.15.3.2.3b-1: Nnef_EventExposure_Subscribe, Unsubscribe and Notify operations or loss of connectivity and UE reachability
1. Step 1 to step 3b of Figure 4.15.3.2.3-1 are performed with the following differences:
- For Loss of Connectivity, the subscription request may include Maximum Detection Time (see Table 4.15.3.1-1).
- For UE reachability, the subscription request may include Maximum Latency, Maximum Response Time and/or Suggested number of downlink packets (see Table 4.15.3.1-1). In step 3a of Figure 4.15.3.2.3-1, the UDM may include Maximum Response Time in the subscription request to the AMF.
NOTE 1: It is expected that Maximum Latency, Maximum Response Time and/or Suggested number of downlink packets included in the subscription request is only used by the AF that does not support Parameter Provisioning procedure specified in clause 4.15.6.3a.
- For UE reachability, the AF may include Idle Status Indication request. If Idle Status Indication request is included, the NEF includes it in Nudm_EventExposure_Subscribe message. If the UDM receives Idle Status Indication request, it includes it in Namf_EventExposure_Subscribe message. If the NEF does not support the requested Idle Status Indication, then depending on operator policies, the NEF rejects the request.
2. [Conditional] If the subscribed periodic registration timer has not been set according to any subscription request, or a Network Configuration as defined in clause 4.15.6.3a the UDM shall set the subscribed periodic registration timer using the Maximum Detection Time or Maximum Latency; otherwise if the subscribed periodic registration timer was previously set by a different subscription identified by a different Notification Target Address (+ Notification Correlation ID), or set by a different Network Configuration identified by a different NEF reference ID for the same UE and if the newly received Maximum Detection Time or Maximum Latency is lower than the provided subscribed periodic registration timer, the UDM shall set the subscribed periodic registration timer using the newly received Maximum Detection Time or Maximum Latency.
If Nudm_EventExposure_Unsubscribe request is performed in step 1, the UDM shall recalculate the subscribed periodic registration timer based on the remaining event subscriptions and/or Network Configurations.
In addition for UE reachability subscription, if the newly received Maximum Response Time is longer than the provided subscribed Active Time (i.e. previously provided Maximum Response Time), the UDM shall set the subscribed Active Time using the newly received Maximum Response Time. If the suggested number of downlink packets is newly received, the UDM shall add the newly received suggested number of downlink packets to the currently used value of suggested number of downlink packets if the aggregated value is within the operator defined range.
If Nudm_EventExposure_Unsubscribe request is performed in step 1, the UDM shall recalculate the subscribed Active Time and/or Suggested Number of Downlink Packets based on the remaining event subscriptions and/or Network Configurations.
If the subscribed periodic registration timer or the subscribed Active Time are set or modified, the UDM sends the Nudm_SDM_Notification request to related serving AMF(s). If the AMF receives a subscribed periodic registration timer value from the UDM, it allocates the received value to the UE as the periodic registration timer at subsequent Registration procedure. The AMF starts monitoring of the expiration of the mobile reachable timer for Loss of Connectivity (if required) and starts monitoring of the UE entering connected mode for UE reachability (if required).
If the suggested number of downlink packets are set or modified, the UDM sends the Nudm_SDM_Notification request to related serving SMF(s). The SMF configures the data buffer at the SMF/UPF according the suggested number of downlink packets.
If the provided value is updated by the UDM, the UDM may notify the NEF (which then notifies the AF) of the actual value that is being applied in the 3GPP network.
3. Step 4 to step 5 of Figure 4.15.3.2.3-1 are performed.
4. Step 6c to step 6d of Figure 4.15.3.2.3-1 are performed with the following differences:
- For Loss of Connectivity, the event is detected when the mobile reachability timer expires or when the UE has provided Unavailability Period Duration during the Registration procedure without including Start of Unavailability Period or when unavailability period starts based on Start of Unavailability Period stored in UE context at AMF or Deregistration procedure as described in clause 5.4.1.4 of TS 23.501 [2].
- For UE reachability, the event is detected when the UE changes to connected mode or when the UE will become reachable for paging.
- For UE reachability, if Idle Status Indication request was included in step 1 and the AMF supports Idle Status Indication, the AMF includes also the Idle Status Indication.
5. Step 8 of Figure 4.15.3.2.3-1 is performed.
4.15.3.2.3c Specific NEF service operations information flow for group member list change
The procedure is used by the AF to subscribe to notifications and to explicitly cancel a previous subscription for group member list change.
Step 1, step 2, step 4, step 5, step 6a and step 7 of Figure 4.15.3.2.3-1 are performed with the differences that the Event ID is set with "Group Member List Change". When a NF consumer subscribes to the group member list change event, if the request indicates immediate reporting, the group member list is provided in the Nudm/Nnef_EeventEExposure_Subscribe response,
When the UDM detects the group member list change event occurs, it sends the event report including the identities of the UE(s) added/removed to/from the group to the NEF by means of Nudm_EventExposure_Notify message and NEF forwards the information to the AF by means of Nnef_EventExposure_Notify message. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.3.2.4 Exposure with bulk subscription | Based on operator configuration NEF may perform bulk subscription with the NFs that provides necessary services. This feature is controlled by local policies of the NEF that control which events (set of Event ID(s)) and UE(s) are target of a bulk subscription.
When the NEF performs bulk subscription (subscribes for any UE (i.e. all UEs), group of UE(s) (e.g. identifying a certain type of UEs such as IoT UEs)), it subscribes to all the NFs that provide the necessary services (e.g. In a given PLMN, NEF may subscribe to all AMFs that support reachability notification for IoT UEs). Upon receiving bulk subscription from the NEF, the NFs store this information. Whenever the corresponding event(s) occur for the requested UE(s) as in bulk subscription request, NFs notify the NEF with the requested information.
The following call flow shows how network exposure can happen for one UE, groups of UE(s) (e.g. identifying a certain type of UEs such as IoT UEs) or any UE.
Figure 4.15.3.2.4-1: NF registration/status notification and Exposure with bulk subscription
1. NEF registers with the NRF for any newly registered NF along with its NF services.
2. When an NF instantiates, it registers itself along with the supported NF services with the NRF.
3. NRF acknowledges the registration
4. NRF notifies the NEF with the newly registered NF along with the supported NF services.
5. NEF evaluates the NF and NF services supported against the pre-configured events within NEF. Based on that, NEF subscribes with the corresponding NF either for a single UE, group of UE(s) (e.g. identifying a certain type of UEs such as IoT UEs), any UE. NF acknowledges the subscription with the NEF.
6 - 7. When the event trigger happens, NF notifies the requested information towards the subscribing NEF along with the time stamp. NEF may store the information in the UDR along with the time stamp using either Nudr_DM_Create or Nudr_DM_Update service operation as appropriate.
8. Application registers with the NEF for a certain event identified by event filters. If the registration for the event is authorized by the NEF, the NEF records the association of the event and the requester identity.
9 - 10. When the event trigger happens, NF notifies the requested information towards the subscribing NEF. NEF may store the information in the UDR using either Nudr_DM_Create or Nudr_DM_Update service operation as appropriate.
11a-b. NEF reads from UDR with Nudr_DM_Query and notifies the application along with the time stamp for the corresponding subscribed events. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.3.2.5 Information flow for downlink data delivery status with SMF buffering | The procedure is used if the SMF requests the UPF to forward downlink data packets that are subject of extended buffering in the SMF. The procedure describes a mechanism for the Application Function to subscribe downlink data delivery status notifications. The downlink data delivery status notifications relates to high latency communication, see also clauses 4.24.2 and 4.2.3.3.
Cancelling the subscription is done by sending Nnef_EventExposure_Unsubscribe request identifying the subscription to cancel with Subscription Correlation ID in the same order as indicated in figure 4.15.3.2.5-1 for the corresponding subscribe requests. Step 0 and the notification steps 7 to 9 are not applicable in cancellation case.
Figure 4.15.3.2.5-1: Information flow for downlink data delivery status with SMF buffering
0. The SMF (in the non-roaming case the SMF, in the roaming case the V-SMF, in the case of PDU session with I-SMF the I-SMF) configures the relevant UPF to forward downlink data packets towards the SMF as described in clause 5.8.3 in 23.501 [2]. The SMF decides to apply this behaviour based on the "expected UE behaviour". Alternatively, step 0 is triggered by step 3,
1. The AF sends Nnef_EventExposure_Subscribe Request to NEF requesting notification for event "Downlink data delivery status" with traffic descriptor (e.g. the source of the downlink IP or Ethernet traffic) for a UE or group of UEs. If the reporting event subscription is authorized by the NEF, the NEF records the association of the event trigger and the requester identity. The Downlink data delivery status events include:
- First downlink Packet in extended buffering event:
- This event is triggered when the first new downlink data packet is buffered with extended buffering matching the traffic descriptor.
- in notifications about this Downlink data delivery status, the SMF provides the Extended Buffering time as determined in clause 4.2.3.3.
- First downlink Packet discarded:
- This event occurs when the first packet matching the traffic descriptor is discarded because the Extended Buffering time, as determined by the SMF, expires or the amount of downlink data to be buffered is exceeded.
- First Downlink Packet transmitted:
- This event occurs when the first packet matching the traffic descriptor is transmitted after previous buffering or discarding of corresponding packet(s) because the UE of the PDU Session becomes ACTIVE and buffered data can be delivered to UE according to clause 4.2.3.3.
2. The NEF sends the Nudm_EventExposure_Subscribe Request to UDM. Identifier of the UE or group of UEs, the traffic descriptor, monitoring event received from AF in step 1 and notification endpoint of the NEF are included in the message. If the reporting event subscription is authorized by the UDM, the UDM records the association of the event trigger and the requester identity. Otherwise, the UDM continues in step 5 indicating failure.
3. The UDM sends the Nsmf_EventExposure_Subscribe Request message to each SMF where at least one UE identified in step 2 has a PDU session established. If the UDM is able to derive the applicable DNN and S-NSSAI from the traffic descriptor via configured information, the UDM may send Nsmf_EventExposure_Subscribe Request messages only to SMFs with PDU sessions with that DNN and S-NSSAI for such UEs and includes the Identifier of the UE or Internal-Group-Id, traffic descriptor, monitoring event and the notification endpoint of NEF received in step 2 are included in the message. If the UDM becomes aware that such a UE has a PDU session established with the DNN and S-NSSAI corresponding to the traffic descriptor at a later time than when receiving step 2, the UDM then executes step 3.
In the case of home-routed PDU session or PDU session with I-SMF, the UDM sends the Nsmf_EventExposure_Subscribe Request message to each H-SMF or SMF and the H-SMF or SMF further sends Nsmf_EventExposure_Subscribe Request message to each related V-SMF or I-SMF. Steps 7-8 are performed by V-SMF or I-SMF.
4. The SMF sends the Nsmf_EventExposure_Subscribe Response message to the UDM.
5. The UDM send sends the Nsmf_EventExposure_Subscribe response message to the NEF.
6. The NEF sends the Nsmf_EventExposure_Subscribe response to the AF.
7. The SMF detects a change in Downlink Data Delivery Status event as described in clause 4.2.3. The SMF becomes aware that Downlink Packet(s) require extended buffering via a Namf_Communication_N1N2MessageTransfer service operation with the AMF. If the SMF decides to discard packets, the "Downlink Packet(s) discarded event" is detected. The SMF detects that previously buffered packets can be transmitted by the fact that the related PDU session becomes ACTIVE.
8. The SMF sends the Nsmf_EventExposure_Notify with Downlink Delivery Status event message to NEF.
9. The NEF sends Nnef_EventExposure_Notify with Downlink Delivery Status event message to AF. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.3.2.6 GMLC service operations information flow | The procedure is used by the NF to subscribe to notifications and to explicitly cancel a previous subscription. The GMLC service operations information flow is defined in clause 6.1.2 and clause 6.3 of TS 23.273 [51]. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.3.2.7 Information flow for Availability after DDN Failure with SMF buffering | The procedure is used if the SMF requests the UPF to forward packets that are subject of buffering in the SMF. The procedure describes a mechanism for the Application Function to subscribe to notifications about availability after downlink data notification failure. The Availability after Downlink Data Notification failure event is related to high latency communication, see also clauses 4.24.2 and 4.2.3.3.
Cancelling the subscription is done by sending EventExposure_Unsubscribe requests identifying the subscription to cancel with the Subscription Correlation ID in the same order as indicated in figure 4.15.3.2.7-1 for the corresponding subscribe requests (the AMF unsubscribes the DDN Failure status notification by sending the Nsmf_PDUSession_UpdateSMContext Request message to each SMF in step 5). Step 0 and the notification steps 9 to 13 are not applicable in the cancellation case.
Figure 4.15.3.2.7-1: Information flow for availability after DDN Failure with SMF buffering
0. The SMF (in the no-roaming case the H-SMF. in the roaming case the V-SMF, in the case of PDU session with I-SMF the I-SMF) configures the relevant UPF to forward packets to the SMF as described in clause 5.8.3 in 23.501 [2]. The SMF decides to apply this behaviour based on the "expected UE behaviour". Alternatively, step 0 is triggered by step 5.
1. The AF sends Nnef_EventExposure_Subscribe Request to the NEF requesting notifications for "Availability after DDN Failure" for a UE or group of UEs and providing a traffic descriptor identifying the source of the downlink IP or Ethernet traffic. If the reporting event subscription is authorized by the NEF, the NEF records the association of the event trigger and the requester identity.
The AF may include Idle Status Indication request in the Nnef_EventExposure_Subscribe Request. If Idle Status Indication request is included, the NEF includes it in Nudm_EventExposure_Subscribe message. If the NEF does not support the requested Idle Status Indication, then depending on operator policies, the NEF rejects the request.
2. The NEF sends the Nudm_EventExposure_Subscribe Request to UDM. Identifier of the UE or group of UEs, the traffic descriptor, monitoring event received from AF at step 1 and notification endpoint of the NEF are included in the message. If the reporting event subscription is authorized by the UDM, the UDM records the association of the event trigger and the requester identity. Otherwise, the UDM continues in step 7 indicating failure.
If the UDM receives Idle Status Indication request, it includes it in Namf_EventExposure_Subscribe message.
3. The UDM sends Namf_EventExposure_Subscribe messages to the AMF(s) which serve the UE(s) identified in step2 to subscribe to "Availability after DDN Failure". The UDM includes the DNN and S-NSSAI as well as the Traffic Descriptor if available A separate subscription is used for each UE. The NEF notification endpoint received in step 2 is included in the message. If the UDM becomes aware that such a UE is registered at a later time than when receiving step 2, the UDM then executes step 3.
4. The AMF acknowledges the execution of Namf_EventExposure_Subscribe.
5. If PDU Session exists for the DNN and S-NSSAI, the AMF subscribes to DDN Failure status notification by sending the Nsmf_PDUSession_UpdateSMContext Request message to each SMF, requesting the SMF to notify DDN Failure. The AMF also includes in Nsmf_PDUSession_UpdateSMContext the Traffic Descriptor and NEF correlation ID if received from the UDM. For new PDU Session establishment towards a DNN and S-NSSAI, the AMF subscribes to DDN Failure status notification in Nsmf_PDUSession_CreateSMContext Request message if the UDM has subscribed to Availability after DDN Failure event.
In the case of home-routed PDU session or PDU session with I-SMF, the AMF sends Nsmf_PDUSession_UpdateSMContext Request message(s) to the related V-SMF(s) or I SMF(s). Steps 9-10 are performed by those V-SMF(s) or I-SMF(s).
6. The (I/V-)SMF sends the Nsmf_PDUSession_UpdateSMContext response message to the AMF.
NOTE: Step 7 can happen any time after step 4.
7. The UDM sends the Nudm_EventExposure_Subscribe response to the NEF.
8. The NEF sends the Nsmf_EventExposure_Subscribe response to the AF.
9-10. The SMF is informed that the UE is unreachable via a Namf_Communication_N1N2MessageTransfer service operation. The SMF then decides to discard downlink packets received from the UPF. By comparing those discarded downlink packets received from the UPF with the Traffic Descriptor(s) received in the event subscription(s), the SMF determines whether DDN Failure due to any traffic from an AF is to be notified to the AMF and if so, the SMF sends the DDN Failure status, by means of Nsmf_PDUSession_SMContextStatusNotify message including NEF Correlation ID, to the AMF. If the UE is not reachable after the AMF received the DDN Failure notification from the SMF, the AMF shall set a Notify-on-available-after-DDN-failure flag corresponding to the NEF Correlation ID.
11-12. [Conditional] The AMF detects the UE is reachable and sends the event report(s) based on the Notify-on-available-after-DDN-failure flag, by means of Namf_EventExposure_Notify message(s), only to the NEF(s) indicated as notification endpoint(s) identified via the corresponding subscription in step 3. In this way, only the AF(s) for which DL traffic transmission failed are notified.
If the AMF received Idle Status Indication request in step 3 and the AMF supports Idle Status Indication, the AMF includes also the Idle Status Indication.
13. The NEF sends Nnef_EventExposure_Notify message with the "Availability after DDN Failure" event to AF. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.3.2.8 Information flow for downlink data delivery status with UPF buffering | The procedure is used if the SMF requests the UPF to buffer packets. The procedure describes a mechanism for the Application Function to subscribe to notifications about downlink data delivery status. The downlink data delivery status notifications relates to high latency communication, see also clauses 4.24.2 and 4.2.3.3.
Cancelling is done by sending Nnef_EventExposure_Unsubscribe request identifying the subscription to cancel with Subscription Correlation ID. Steps 2 to 5 are not applicable in the cancellation case.
Figure 4.15.3.2.8-1: Information flow for downlink data delivery status with UPF buffering
1. AF interacts with NEF to subscribe DDD status event in SMF as described in steps 0-6 of clause 4.15.3.2.5.
In the case of subscription cancelling and SMF having interacted with the PCF during event subscription, the SMF reports to the PCF the unsubscribe of the DDD status event. The PCF updates or removes the PCC rule and this triggers the SMF to update or remove the corresponding PDR in the UPF. In case of home-routed PDU Session, the SMF unsubscribes the DDD status event from the V-SMF which in turn updates the N4 information (deactivating the notifications) in the V-UPF. In case of PDU Session with I-SMF, the SMF provides updated N4 information (deactivating the notifications) to the I-SMF which in turn updates the I-UPF.
2. If the UPF is configured to apply extended buffering, step 2 is executed immediately after step 1. Otherwise, step 2 is executed when the SMF is informed that the UE is unreachable via a Namf_Communication_N1N2MessageTransfer service operation as described in clause 4.2.3 and the SMF then also updates the PDR(s) for flows requiring extended buffering to requests the UPF to buffer downlink packets. If the DDD status event with traffic descriptor has been received in the SMF in step 1, if extended DL Data buffering in the UPF applies, the SMF checks whether an installed PDR for the Traffic Descriptor exists and if so, requests the UPF to provide the requested type(s) of notifications. If PCC is not used and there is no installed PDR with the exact same traffic descriptor, the SMF copies the installed PDR that would have previously matched the incoming traffic described by the traffic descriptor, but provides that traffic descriptor, a higher priority and the requested type(s) of notifications. If PCC is used and if the "DDD Status event subscription with Traffic Descriptor" PCRT is set as defined in clause 6.1.3.5 of TS 23.503 [20], the SMF interacts with the PCF and forwards the traffic descriptor before contacting the UPF; the PCF then updates an existing PCC rule or provides a new PCC rule taking into consideration the traffic descriptor for the subscribed DDD status event.
NOTE: If a new PCC rule is provided by the PCF for the DDD status event detection, the PCF populates the PCC rules as defined in clause 6.1.3.5 of TS 23.503 [20].
In the case of home-routed PDU Session, the V-SMF generates the N4 information (activating the notifications) for the V-UPF based on local configuration.
In the case of PDU Session with I-SMF, the SMF provides N4 information (activating the notifications) to the I-SMF based on local policy or the "DDD Status event subscription with Traffic Descriptor" PCRT from PCF. The I-SMF updates the I-UPF with this N4 information.
For home-routed PDU Session or PDU Session with I-SMF, steps 3-4 below are performed by V-SMF/V-UPF or I-SMF/I-UPF.
3. The UPF reports when there is buffered or discarded traffic matching the received PDR to the SMF. The SMF detects that previously buffered packets can be transmitted by the fact that the related PDU session becomes ACTIVE.
4. The SMF sends the Nsmf_EventExposure_Notify with Downlink Delivery Status event message to NEF.
5. The NEF sends Nnef_EventExposure_Notify with Downlink Delivery Status event message to AF. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.3.2.9 Information flow for Availability after DDN Failure with UPF buffering | The procedure is used if the SMF requests the UPF to buffer packets. The procedure describes a mechanism for the Application Function to subscribe to notifications about availability after DDN failure.
Cancelling is done by sending Nnef_EventExposure_Unsubscribe request identifying the subscription to cancel with Subscription Correlation ID. Steps 2 to 7 are not applicable in the cancellation case.
Figure 4.15.3.2.9-1: Information flow for availability after DDN Failure event with UPF buffering
1. AF interacts with NEF to subscribe availability after DDN failure event in AMF/SMF as described in steps 0-8 of clause 4.15.3.2.7.
In case of subscription cancelling from AMF and SMF having interacted with the PCF during event subscription, the SMF reports to the PCF for the unsubscribe of DDN failure event. The PCF updates or removes the PCC rule and this triggers the SMF to update or remove the corresponding PDR and FAR in the UPF.
In the case of PDU Session with I-SMF or home-routed PDU Session, the AMF unsubscribes the DDN failure event towards I/V-SMF. In case of home-routed PDU Session, the V-SMF updates the N4 information (deactivating the notifications) in the V-UPF. In case of PDU Session with I-SMF, the I-SMF may request N4 information (deactivating the notifications) from the SMF and provides the Traffic Descriptor to the SMF. The SMF provides updated N4 information (deactivating the notifications) to the I-SMF which in turn updates the I‑UPF.
2. The SMF checks whether an installed PDR for the Traffic Descriptor exists and if so, requests the UPF to report when the first downlink packet is received and when it is discarded in the UPF. If PCC is not used and there is no installed PDR with the exact same traffic descriptor, the SMF copies the installed PDR that would have previously matched the incoming traffic described by the traffic descriptor, but provides that traffic descriptor, a higher priority and requests the UPF to report when the first downlink packet is received and when it is discarded in the UPF.
If PCC is used and if the "DDN Failure event subscription with Traffic Descriptor" PCRT is set as defined in clause 6.1.3.5 of TS 23.503 [20], the SMF interacts with the PCF and forwards the traffic descriptor before contacting the UPF; the PCF then updates an existing PCC rule or provides a new PCC rule taking into consideration the traffic descriptor for the subscribed DDN failure event.
NOTE 1: If a new PCC rule is provided by the PCF for the DDN failure event detection, the PCF populates the PCC rules as defined in clause 6.1.3.5 of TS 23.503 [20].
In the case of PDU Session with I-SMF or home-routed PDU Session, the AMF subscribes the DDN failure event towards the I/V-SMF. In the case of home-routed PDU Session, the V-SMF generates the N4 information (activating the notifications) for the V-UPF based on local configuration.
In the case of PDU Session with I-SMF, the I-SMF may request N4 information (activating the notifications) from the SMF based on local configuration and provides the Traffic Descriptor to the SMF. The SMF provides updated N4 information (activating the notifications) to the I-SMF which in turn updates the I-UPF.
For home-routed PDU Session or PDU Session with I-SMF, steps 3-4 below are performed by V-SMF/V-UPF or I-SMF/I-UPF.
3-4. When the first downlink packet matching the traffic descriptor is received in the UPF, if in step 2 the SMF indicated drop notification to the UPF, the UPF notifies the SMF and the SMF reports the DDN Failure status with NEF Correlation ID, by means of Nsmf_PDUSession_SMContextStatusNotify message, to the AMF indicated as notification endpoint.
When the first downlink packet matching the traffic descriptor is received in the UPF, if in step 2 the SMF indicated buffer notification to the UPF, the UPF notifies the SMF and the SMF may initiate Network Triggered Service Request as specified in clause 4.2.3.3. If the AMF responds Namf_Communication_N1N2MessageTransfer response with failure (e.g. due to UE not reachable, or paging no response), in addition to what is specified in clause 4.2.3.3, the SMF reports DDN Failure status with NEF Correlation ID, by means of Nsmf_PDUSession_SMContextStatusNotify message, to the AMF indicated as notification endpoint.
When the AMF receives DDN Failure status from the SMF, the AMF shall set a Notify-on-available-after-DDN-failure flag corresponding to the Notification Correlation Id and the identifier of the UE if available.
5-6. [Conditional] The AMF detects the UE is reachable and sends the event report(s) based on the Notify-on-available-after-DDN-failure flag, by means of Namf_EventExposure_Notify message(s), only to the NEF(s) indicated as notification endpoint(s) identified via the corresponding subscription in step 1. In this way, only the AF(s) for which DL traffic transmission failed are notified.
If the AMF received Idle Status Indication request in step 1 and the AMF supports Idle Status Indication, the AMF includes also the Idle Status Indication in Namf_EventExposure_Notify message.
7. The NEF sends Nnef_EventExposure_Notify message with the "Availability after DDN Failure" event to AF. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.3.2.10 Number of UEs and PDU Sessions per network slice notification procedure | 4.15.3.2.10.1 Reported value(s) aggregated at NEF
This procedure depicts the case of an AF subscribing to receive the registered number of UEs, or the number of PDU sessions in a specific S-NSSAI. The procedure handles the case when there is a single NSACF in the PLMN responsible for the S-NSSAI (single Service Area) or when there are multiple NSACFs responsible for the S-NSSAI in the PLMN (multiple Service Areas).
Figure 4.15.3.2.10.1-1: Reported value(s) aggregated at NEF per network slice notification procedure
1. To subscribe or unsubscribe for the number of UEs or the number of PDU Sessions per network slice notification with the NEF, the AF sends Nnef_EventExposure Subscribe/Unsubscribe Request (Event ID, Event Filter, Event Reporting information, S-NSSAI) message to the NEF. The Event ID parameter defines the subscribed event ID, i.e. Number of Registered UEs or Number of Established PDU Sessions. The Event Filter parameter defines the S-NSSAI, in case of a trusted AF or AF-Service-Identifier as defined in TS 29.522 [87] for an untrusted AF, for which reporting is required. The Event Reporting information parameter defines the mode of reporting, which includes threshold reporting with a threshold value or periodic reporting with included periodicity time interval. The S-NSSAI is the slice for which the subscription is requested
The AF may request one-time reporting or immediate reporting.
NOTE 1: When immediate reporting but not for one-time reporting is requested, the subscription is maintained after returning the report to the AF. When one-time reporting is requested, the subscription is terminated right after returning the report to the AF.
Notifications related to the threshold based subscriptions behave as follows:
- A single notification is sent only when the number of registered UEs or the number of established PDU Sessions reaches the threshold. A single notification is sent every time there is a change from being below the threshold to reach the threshold.
- A single notification is sent only once when the number of registered UEs or the number of established PDU Sessions go below the threshold after reaching it. A single notification is sent every time there is a change from reaching the threshold to coming down below the threshold.
2. The NEF confirms with Nnef_EventExposure_Subscribe/Unsubscribe Response message to the AF. This message may include the event reporting, if available in the NEF and immediate reporting or one-time reporting was requested by the AF. In the case of Untrusted AF, the NEF includes the AF-Service-Identifier corresponding to the S-NSSAI in the returned notification.
If immediate reporting or one-time reporting is requested, step 2 occurs after step 5 and the subscription response contains the immediate or one-time report. For the case of one-time reporting, no subscription is created at the NEF/NSACF.
3. The NEF may query the NRF to find the NSACF(s) responsible for the requested S-NSSAI. If needed, the NEF translates the AF-Service-Identifier to the corresponding S-NSSAI prior to performing the query.
4. If the NEF has not already subscribed to the event from the NSACF for the requested S-NSSAI, the NEF initiates the request Nnsacf_SliceEventExposure_Subscribe/Unsubscribe Request (Event ID, Event Filter, Event Reporting information, immediate reporting, S-NSSAI) to all the NSACFs supporting the requested S-NSSAI. The NEF stores the AF requested Event Reporting Information. If multiple NSACFs are selected for the requested S-NSSAI, the NEF may set the Event Reporting Information to periodic in its request to the NSACFs. If single NSACF is selected, the NEF sets the Event Reporting Information identical to the received request from the AF. The NEF also sets the Event ID and Event Filter identical to the received request from the AF
NOTE 2: The period chosen is selected by the NEF based on its internal logic.
5. The NSACF(s) confirms with Nnsacf_SliceEventExposure_Subscribe/Unsubscribe Response message to the NEF. This message may include the event reporting if available at NSACF and immediate reporting or one-time reporting was requested by the NEF.
6. When the reporting condition for a subscribed event is fulfilled, the NSACF triggers a notification towards the NEF.
7. The NSACF sends the Nnsacf_SliceEventExposure_Notify (Event ID, Event Reporting information) message to the NEF. If the subscription is for event based notification (e.g. based on the monitored event reaching a threshold value), the Event Reporting information parameter contains confirmation for the event fulfilment. If the subscription is for periodic notification or for immediate reporting, the Event Reporting information parameter provides information for the current number of UEs registered with a network slice (e.g. represented in percentage of the maximum number of the UEs registered with the network slice) or information for the current number of PDU Sessions on a network slice (e.g. represented in percentage of the maximum number of the UEs established on the network slice).
8. When a single NSACF is returned from the discovery procedure, the NEF sends the Nnef_EventExposure_Notify (Event ID, Event Reporting information) message since the reporting condition is fulfilled. In the case of Untrusted AF, the NEF includes the AF-Service-Identifier corresponding to the S-NSSAI in the returned notification.
9. When multiple NSACFs are selected for the requested NSSAI the NEF performs the aggregation from reporting NSACF(s) and maintain the overall usage of the S-NSSAI for the selected NSACFs as long as the subscription is active.
NOTE 3: If multiple NSACFs are selected for the requested S-NSSAI, the NEF continuously updates the aggregated information to be able to fulfil the incoming subscription request from the AF.
10. When multiple NSACFs are selected for the requested S-NSSAI and when the reporting condition for a subscribed event by the AF is fulfilled, the NEF sends Nnef_EventExposure_Notify (Event ID, Event Reporting information) message towards the AF. In case of untrusted AF; the NEF includes the AF-Service-Identifier corresponding to the S-NSSAI in the returned notification.
If the hierarchical NSAC architecture is deployed in the PLMN for the NSAC of an S-NSSAI and the number of UEs, number of UE with at least one PDU session/PDN connection, or number of PDU Sessions are aggregated at NEF, the same procedure as above can be reused. In this case Primary NSACF behaves as a normal NSACF.
4.15.3.2.10.2 Reported value(s) aggregated at Primary NSACF
If the hierarchical NSAC architecture is deployed in the PLMN for the NSAC of an S-NSSAI, the Primary NSACF needs to be aware of the current status of registered UEs, UE with at least one PDU session/PDN connection, or established PDU sessions at all NSACFs with whom it is interacting, so it can dynamically adapt and adjust the local Maximum number of UEs, local Maximum number of UE with at least one PDU session/PDN connection, or PDU sessions configured at the NSACFs. In this case, it is possible to leverage this capability and provide subscribing AFs to receive the registered number of UEs, number of UE with at least one PDU session/PDN connection, or the number of PDU sessions for the requested S-NSSAI without NEF aggregation. Such a procedure is depicted below.
Figure 4.15.3.2.10.2-1: Reported value(s) aggregated at Primary NSACF per network slice notification procedure
1. The AF subscribes (or unsubscribe) to the number of UEs, or the number of PDU Sessions per network slice notification to the NEF. The NEF finds the primary NSACF responsible for the requested S-NSSAI. Based on the network configuration, the NEF does not to do the aggregation. The procedure is same as steps 1-5 of clause 4.15.3.2.10.1 with the following differences:
- Based on the network configuration the NEF is aware that one NSACF can serve entire PLMN for the requested S-NSSAI, i.e. existence of the Primary NSACF. The NEF queries the NRF to find the corresponding primary NSACF responsible for the requested S-NSSAI. Besides the requested S-NSSAI, the Serving Area information of "Entire PLMN" is included as querying parameter. In the case of Trusted AF, the AF can discover and subscribe (or unsubscribe) directly with the Primary NSACF.
- The NEF sets the Event Reporting Information identical to the received request from the AF. The NEF also sets the Event ID and Event Filter identical to the received request from the AF. The Primary NSACF responsible for the requested S-NSSAI performs the aggregation per network configuration.
2-6. The Primary NSACF subscribes (or unsubscribes) to the number of UEs, or the number of PDU Sessions per network slice notification to all the NSACFs supporting the requested S-NSSAI(s). The procedure is same as steps 4-7 of clause 4.15.3.2.10.1 for multiple NSACFs case with the Primary NSACF replacing the NEF and the following differences:
- Step 2, based on the received event subscription from NEF, the Primary NSACF triggers the slice event subscription to NSACF(s) if it does not exist before.
- Step 6, the Primary NSACF performs the aggregated values from reporting NSACF(s) including itself (if available) and maintain the overall usage of the S-NSSAI(s) for the indicated Event ID parameter, i.e. the number of UEs registered with a network slice, number of UE with at least one PDU session/PDN connection, or the number of PDU Sessions established on a network slice, from the selected NSACFs as long as the subscription is active. When the reporting condition for a subscribed event is fulfilled, the Primary NSACF triggers a notification for the event towards the NEF. As values from the NSACF(s) has been aggregated at the Primary NSACF, there is no aggregation to be performed further at the NEF. NEF forwards the received values to AF.
NOTE: For the number of registered UEs per network slice or number of UE with at least one PDU session/PDN connection, the aggregated value includes both the number of registered UE at NSACF(s) and the number of registered UE at Primary NASCF as described in the clause 5.15.11.1.2 of TS 23.501 [2]. For the number of established PDU sessions per network slice, the aggregated value only includes the number of established PDU Sessions at the NSACF(s). |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.3.2.11 Network-initiated explicit event notification subscription cancel procedure | The procedure is used by the UDM to delete an event notification subscription (see clause 4.15.1).
Figure 4.15.3.2.11-1: Network-initiated event subscription removal procedure
0. An event notification subscription procedure according to clause 4.15.3.2.2 or clause 4.15.3.2.2 has already executed successfully.
1-1a. If UE subscription is withdrawn in UDM, UE authorisation to the subscribed monitoring event or UE is removed from the subscribed target group, the UDM triggers Nudm_EventExposure_Notify towards the associated notification endpoint indicating the removal of the event notification along with the time stamp. The NEF may store the information in the UDR along with the time stamp using either Nudr_DM_Create or Nudr_DM_Update service operation as appropriate.
In order to remove certain UEs in a group of UEs for which there is an event notification subscription, the UDM provides impacted UE information (e.g. SUPI, MSISDN or External Identity) to the NEF and indicates the removal of the event notification subscription for these UE(s).
2a-2b. If UE subscription information changes (e.g. UE group information changes), the UDM sends Nudm_SDM_Notification request to related serving AMF(s) to update event notification subscription information. If the UE was a group member of a previous accepted group-based event notification subscription, the AMF shall stop the event notifications for the impacted UEs. If Maximum number of Reports is applied, the AMF shall set the number of reports of the indicated UE(s) to Maximum Number of Reports.
If UE subscription data is withdrawn, the UDM sends Nudm_UECM_DeregistrationNotification request to related serving AMF(s) to remove UE subscription information. If the UE was a group member of a previous accepted group-based event notification subscription, the AMF shall keep the accepted group-based event notification subscription unless all UEs subscriptions in the group are withdrawn.
3. The NEF sends Nnef_EventExposure_Notify to the AF reporting event received by Nudm_EventExposure_Notify.
If the NEF receives UE Identifier(s) in step 1 for a group-based event notification subscription and the Maximum Number of Reports applies to the group-based event notification subscription, the NEF sets the number of reports of the indicated UE(s) to Maximum Number of Reports. The NEF sends Nnef_EventExposure_Notify to the AF and includes MSISDN(s) or External Identifier(s). If NEF determines that the reporting for the group is complete based on the update above, the NEF deletes the associated event notification subscription and requests that the UDM deletes the related event notification subscription for the group. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.3.2.12 Void | |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.3.2.13 Handling AF requests when the UE is identified via UE addressing information | An AF may request, via the NEF, the Event Exposure (as defined in clause 4.15.3) or the parameter provisioning (as defined in clause 4.15.6) targeting an individual UE, identifying the target UE by providing UE addressing information.
In this case the 5GC first needs to retrieve a UE Identifier based on:
- the UE addressing information as provided by the AF: this may correspond to an UE IP address as allocated by 5GC or to a MAC address of the UE (when Ethernet PDU Sessions are targeted),
- the corresponding DNN and/or S-NSSAI: this may have been provided by the AF or, alternatively, determined by the NEF using the identity of the AF.
The NEF retrieves the AF specific UE Identifier from the UDM. The AF specific UE Identifier may be determined in the GPSI form of External Identifier by executing step 2 to 6 of the AF specific UE Identifier retrieval procedure described in clause 4.15.10. If the exposure of MSISDN is allowed in UDM configuration for subscriber and exposure of MSISDN is allowed and authorized by the operator, the AF specific UE Identifier may be determined in the GPSI form of MSISDN, as described in clause 4.15.10A.
Once this is done, the 5GC may carry out the action requested by the AF and may deliver back to the AF an External Identifier, representing an AF specific UE Identifier, or an MSISDN (as defined in TS 23.501 [2]). The exposed AF specific UE Identifier or MSISDN may later be used by the AF to issue further requests about the same UE.
NOTE: The AF can use UE addressing information to identify the UE in a subscription request, but once received, this UE addressing information is translated into a GPSI and then the 5GC considers the subscription is associated with the GPSI and not with the UE address any more.
The AF may have its own means to maintain the AF specific UE Identifier through, e.g. an AF session. After the retrieval of an AF specific UE Identifier the AF shall not keep maintaining a mapping between the returned AF specific UE Identifier and the UE IP address as this mapping may change. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.3.3 Void | |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.4 Core Network Internal Event Exposure | |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.4.1 General | The exposure of events internally within the 5GC NFs is explained in the following clauses. Only the event notifications that are independent of the ongoing system procedure are specified in this clause. For the event notifications that are part of the system procedure, see the system procedure descriptions under clause 4.2 to clause 4.14. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.4.2 Exposure of Mobility Events from AMF | The AMF invokes the Namf_EventExposure_Notify to provide mobility related events to NF consumers that have subscribed for the events by invoking Namf_EventExposure_Subscribe, in the following scenarios listed below and after Namf_EventExposure_Subscribe service operation.
- During Registration procedure, Inter NG-RAN node N2 based handover procedure, when there is a change of AMF (within the same AMF Set or across the AMF Set), the new AMF receives all event subscriptions from old AMF or UDSF. For each event subscription:
if the event subscription only applies to the UE, the new AMF allocates a new Subscription Correlation ID and notify the NF consumer of the new Subscription Correlation ID associated with the change of Subscription Correlation ID event.
if the event subscription applies to a group of UE(s) and there is no corresponding subscription for this group (identified by the internal group Id and notification endpoint) at the new AMF, the new AMF shall create corresponding event subscription, allocate a new Subscription Correlation Id and send it to the received notification endpoint, i.e. Notification Target Address (+Notification Correlation Id), associated with the addition of Subscription Correlation ID event. The new AMF does not need to allocate another Subscription Correlation ID for any subsequent registrations of the members of the same group. The initial Maximum number of reports and the remaining number of reports within the Maximum number of reports quota for the UE is transferred from the old AMF.
NOTE: For group monitoring, even if the remaining number of reports is zero, indicating that reporting for the group event has been completed by the old AMF for this UE, the new AMF uses the received information related to initial event subscription to create the corresponding group event subscription.
- During Registration procedure, when there is a change of AMF, the new AMF notifies each NF that has subscribed for UE reachability event about the UE reachability status.
- During Registration, Handover, UE Triggered Service Request procedure in CM-IDLE state, Location Reporting, N2 Notification and AN Release procedures, the AMF determines the UE presence in Area Of Interest (i.e. IN, OUT or UNKNOWN status ) as described in Annex D.1 and notifies the NF Consumers of the UE presence in an Area Of Interest if the NF consumers (e.g. SMF) had subscribed for this Area Of Interest and if the UE presence in Area Of Interest is different from the one reported earlier.
- During Registration and Handover procedure or during Service Area Restriction update by UDM or PCF, if the UE is moving from an Allowed Area to a Non-Allowed Area, then the AMF informs all the NF consumers (e.g. SMF), that have subscribed for UE reachability event, that the UE is reachable only for regulatory prioritized service. The SMF shall explicitly subscribe UE reachability unless the established PDU Session is related to regulatory prioritized service.
- If the AMF had notified an SMF of the UE being reachable only for regulatory prioritized service earlier, the AMF informs the NF consumers (e.g. SMF), that have subscribed for UE reachability event, that the UE is reachable if the UE enters into Allowed Area.
- During Registration procedure and Service Request procedure, if the AMF had notified an SMF earlier of the UE being unreachable and that SMF need not invoke Namf_Communication_N1N2MessageTransfer to the AMF due to DL data notifications, the AMF informs the SMF when the UE becomes reachable.
- During Registration procedure and Service Request procedure, if the AMF had notified an SMF earlier that the UE is unreachable together with an Estimated Maximum Wait time, then the AMF informs the SMF when the UE becomes reachable. When the SMF learns that the UE is reachable and:
- if the SMF performs Extended Buffering for a PDU session, the SMF sends the buffered data to the UPF and invokes the Namf_Communication_N1N2MessageTransfer service operation to the AMF to establish the User Plane(s) for the PDU Sessions, or the buffered data is delivered to the UE as per the procedure in clause 4.24.2 starting from step 2g for a PDU session using Control Plane CIoT 5GS Optimisation;
- if the UPF performs Extended Buffering for a PDU session, the SMF invokes the Namf_Communication_N1N2MessageTransfer service operation to the AMF to establish the User Plane(s) for the PDU Sessions, or the buffered data is delivered to the UE as per the procedure in clause 4.24.2 starting from step 8a for a PDU session using Control Plane CIoT 5GS Optimisation.
- If NEF had subscribed for UE reachability event notification for Extend Buffering, then the AMF informs the NEF when the UE becomes reachable. When the NEF learns that the UE is reachable, it invokes the Nsmf_NIDD_Delivery service operation of the corresponding SMF to deliver the buffered data to the UE as per the procedure in clause 4.25.5 starting from step 2 for a PDU session using Control Plane CIoT 5GS Optimisation.
- During Registration procedure, Handover without Registration procedure and Service Request procedure, if the NF consumers had subscribed for UE reachability status, the AMF notifies the UE reachability status changes.
- If the Mobile Reachable Timer expires the AMF notifies the NF consumers that have subscribed for the corresponding events that the UE is not reachable.
- If the UDM had subscribed for UE reachability event notification either to be reported to the UDM or to an NF consumer directly, then the AMF notifies the UE reachability event to the UDM or to the NF consumer as specified in clause 4.2.5.2.
- If UE's TAC is already known by the AMF, then, the AMF notifies UE TAC to the NF consumers (e.g. to NWDAF). If UE TAC is unknown, then the AMF notifies the UE TAC when it obtained the UE TAC from the UE.
During Connection, Registration and Mobility Management procedures, the AMF may store and update the UE access behaviour trends specified in Table 4.15.4.2-1 and the UE location trends specified in Table 4.15.4.2-2. Each metrics is updated incrementally, e.g. using exponential moving average. This information is exposed to consumer NFs (e.g. NWDAF) that subscribe for the event ID "UE access behaviour trends" and/or "UE location trends", respectively, by invoking Namf_EventExposure_Subscribe.
Table 4.15.4.2-1: UE access behaviour trends exposed by AMF
Information
Description
UE Identity
SUPI
List of state transitions
> State transition type
State transition identifier:
- "Access Type change to 3GPP access",
- "Access Type change to non-3GPP access",
- "RM state change to RM-DEREGISTERED",
- "RM state change to RM-REGISTERED ",
- "CM state change to CM-IDLE",
- "CM state change to CM-CONNECTED",
- "Handover", or
- "Mobility Registration Update".
> Spacing
Average and variance of the time interval separating two consecutive occurrences of the state transition.
> Duration
Average and variance of duration in the resulting state.
Table 4.15.4.2-2: UE location trends
Information
Description
UE Identity
SUPI
List of location information (1..N)
> UE Location
TAI, Cell-ID (if available), non-3GPP access identity.
> Spacing
Average and variance of the time interval separating two consecutive arrivals at this location.
> Duration
Average and variance of duration of stay in the location.
> Timestamp
Timestamp of last arrival in the location.
NOTE: The maximum size of the list (N) is defined per configuration and only the N entries with the highest average value of "Duration" are kept in the list. The list is ordered by descending order of "Duration". |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.4.3 Exposure of Communication trends from SMF | During Session Management procedures, the SMF may store and update the UE access behaviour trends specified in Table 4.15.4.3-1 and the UE communication trends specified in Table 4.15.4.3-2. Each metrics is updated incrementally, e.g. using exponential moving average. This information is exposed to consumer NFs (e.g. NWDAF) that subscribe for the event ID "UE session behaviour trends" and/or "UE communication trends", respectively, by invoking Nsmf_EventExposure_Subscribe.
Table 4.15.4.3-1: UE session behaviour trends exposed by SMF
Information
Description
UE Identity
SUPI
List of state transitions
> State transition type
State transition identifier:
- "PDU Session Establishment",
- "PDU Session Release",
- "Communication failure", or
- "PLMN change".
> Spacing
Average and variance of the time interval separating two consecutive occurrences of the state transition.
Table 4.15.4.3-2: UE communication trends
Information
Description
UE Identity
SUPI
List of communication information (1..N)
> Communication characteristics
S-NSSAI and DNN
> Spacing
Average and variance of the time interval separating two consecutive PDU Session Establishment procedures corresponding to the communication characteristics.
> Duration
Average and variance of duration of PDU Sessions corresponding to the communication characteristics.
> Timestamp
Timestamp of the last PDU Session Establishment procedure corresponding to the communication characteristics.
NOTE: The maximum size of the list (N) is defined per configuration and only the N entries with the highest average value of "Duration" are kept in the list. The list is ordered by descending order of "Duration". |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.4.4 Internal Event Exposure Subscription/Unsubscription via UDM | This clause describes an indirect method of event exposure subscription in AMF and SMF via UDM for a UE or group of UEs. This can be used after the removal of UE context in the AMF including event exposure subscriptions, or the creation of new UE context in AMF or SMF. In this case, the UDM is responsible for (re)creating event exposure subscriptions in AMF and SMF.
Figure 4.15.4.4-1: Internal Event exposure subscription/unsubscription in AMF or SMF via UDM
1. A consumer of event exposure for events detected in AMF or SMF (e.g. NWDAF) sends an Nudm_EventExposure Subscribe/Unsubscribe request to the UDM for a UE or group of UEs, including the subscription details (Event ID, Event filters, etc.).
2. UDM examines the event type and subscription details to determine whether one or more events are to be detected by the AMF. In this case, for those applicable events that are detected by the AMF, if an AMF is registered in UDM for the UE (or for a UE that is member of the group of UEs), UDM creates an Namf_EventExposure Subscribe/Unsubscribe request and sends it to the AMF of the UE, including the subscription details.
3. AMF answers with an Namf_EventExposure Subscribe/Unsubscribe response.
4. UDM examines the event type and subscription details to determine whether one or more events are to be detected by the SMF. In this case, for those applicable events that are detected by the SMF, if one or more SMFs are registered in UDM for the UE (or for a UE that is member of the group of UEs), UDM creates an Nsmf_EventExposure Subscribe/Unsubscribe request and sends it to each applicable SMF of the UE, including the subscription details.
5. SMF answers with an Nsmf_EventExposure Subscribe/Unsubscribe response.
6. UDM sends an Nudm_EventExposure Subscribe/Unsubscribe response to the consumer of event exposure. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.4.5 Exposure of Events from UPF for UPF Data Collection | |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.4.5.1 General | This clause contains the detailed description and the procedures for how the UPF event exposure service (see clause 5.2.26.2) is used for UPF data collection.
The list of NF consumer which may receive UPF event notifications is defined in clause 5.8.2.17 of TS 23.501 [2].
To get exposure data from UPF, NF consumer may subscribe to the UPF directly or indirectly via SMF. This is further defined in clause 5.8.2.17 of TS 23.501 [2].
The UPF event exposure events are described in clause 5.2.26.2. In this Release of the specification, the following events are used for UPF Data collection:
- QoS Monitoring. This event provides QoS Flow performance information.
- User DataUsage Measures. This event provides information of user data usage of the User PDU Session.
- User DataUsage Trends. This event provides statistics related to user data usage of the User PDU Session.
A consumer of UPF event exposure can subscribe to QoS monitoring event via SMF only and UPF sends the QoS Flow Performance information directly to this consumer. For this event, the interaction between SMF and UPF is over PFCP (TS 29.244 [69]). TS 23.501 [2] describes the QoS monitoring parameters that can be measured by means of QoS monitoring and how to enable the measurements for QoS flows. When the Subscription request for QoS monitoring event indicates that it is for the QoS Flow associated with the default QoS rule, based on local configuration the subscription request may trigger SMF to enable QoS monitoring.
NOTE 1: Packets from multiple applications may share the QoS Flow associated with the default QoS Rule which may diminish the relevance of some measurements like data rate.
The subscription to QoS monitoring event can target the QoS flows bound to an application by including an Application Identifier. In this case, at subscription request and/or when the PCC rules change, SMF identifies the active PCC Rule that includes a DataCollection_ApplicationIdentifier matching that Application Identifier. SMF enables this consumer (e.g. NWDAF) to receive the QoS Monitoring reports enabled by that PCC Rule. The consumer may indicate that it can receive QoS Flow Performance information for the QoS Flow associated with the default QoS rule if there are no measurements available for the Application Identifier (that is, if no PCC rule is identified). In this case the SMF may instruct the UPF to perform QoS monitoring for the QoS Flow associated with the default QoS rule and include the Indication of QoS Flow associated with the default QoS Rule (see clause 5.8.2.18 of TS 23.501 [2]). The UPF will then include the Indication of QoS Flow associated with the default QoS Rule in the Nupf_EventExposure_Notify service operation when sending reports. Otherwise, the SMF may accept the request and indicate in the response that reporting will be activated when the measurements are enabled by a PCC rule or the SMF may reject the subscription request for that Application Identifier.
NOTE 2: Extensive usage of QoS Monitoring has significant impact on load and signalling.
A consumer of UPF event exposure such as NWDAF/AF/NEF may subscribe to User Data Usage events (i.e. User Data Usage Measures and User Data Usage Trends) directly to UPF (under the conditions defined in clause 5.8.2.17 of TS 23.501 [2]) or via SMF, and UPF sends the event notifications directly to this consumer. For these events, the interaction between SMF and UPF is over SBI. For User Data Usage events, the subscription request targets the traffic matching Event Filter Information (details are described in clause 5.2.26.2.1) for a user's PDU Session or for each PDU Session served by the UPF. The subscription request may indicate the granularity requested, that is whether the measurement reports should be provided per data flow, per application, or per PDU Session.
If the event notification can be delayed, i.e. delay tolerant, Reporting suggestion information is included. The Reporting suggestion information includes Report urgency and Reporting time information. Reporting urgency information indicates whether this event report can be delay tolerant, i.e. the event report can be delayed. If the Reporting urgency information indicates "delay tolerant", the Reporting time is also provided, which defines the last valid reporting time and UPF shall report the detected event before the last valid time.
If a consumer subscribes to an UPF event via the SMF including an AoI ("Area of Interest"), the SMF starts the subscription to the UPF only when the UE is located in the requested AoI. When the UE leaves the AoI, the SMF stops the subscription on the UPF. The SMF may subscribe to AMF about UE moving in or out of an AoI for this purpose. Clause 4.15.4.5.4 describes an alternative procedure for subscription via SMF to UPF event exposure service related with AOI.
If a consumer of UPF event exposure include a Remaining data reporting indication, UPF should send the collected data to the consumer at N4 session release (details are described in clauses 4.15.4.5.6 and 4.15.4.5.7).
Table 4.15.4.5.1-1: Input parameters in subscription to UPF event Exposure events
Information
To SMF
To UPF
(NOTE 4)
UE identification (NOTE 5)
Y
Y
Any UE
Y
Y
DNN
Y
Y (NOTE 6)
S-NSSAI
Y
Y (NOTE 6)
AOI
Y
N
BSSID/SSID
Y
N
DNAI (NOTE 3)
Y
N
UPF Id (NOTE 3)
Y
not applicable
Type of Measurement
Y
Y
Granularity of Measurement (NOTE 2)
Y
Y
Application ID (NOTE 1)
Y
Y
Traffic Filtering Information (NOTE 1), (NOTE 2)
Y
Y
Reporting suggestion information
Y
Y
Remaining data reporting indication
Y
Y
Subscription termination reporting indication
N
Y
NOTE 1: Application ID and Traffic Filtering Information are exclusive.
NOTE 2: This parameter does not apply to QoS monitoring event.
NOTE 3: This parameter is used to indicate a UP Path as defined in Table 6.4.1-1 of TS 23.288 [50].
NOTE 4: This column is not applicable to events where SMF-UPF interactions are using PFCP (e.g. QoS Monitoring event). That interaction is described in clause 5.8.5 of TS 23.501 [2].
NOTE 5: Input parameter when the target is a UE. When the target is a UE, the SUPI is the the UE identification input to SMF.
For IP PDU session type, the UE identification input to the UPF shall be the UE IP address associated with the PDU session.
For non-IP PDU session types, when the UPF is allowed by local SMF configuration to receive the SUPI associated with a N4 session, the UE identification input to the UPF is the SUPI.
UPF event Exposure targeting a UE is not supported for non-IP PDU session types, when the UPF is not allowed by local SMF configuration to receive the SUPI associated with a N4 session.
NOTE 6: In a deployment where UPF reporting filtered per DNN and /or S-NSSAI is expected, the SMF should provide UPF with the necessary information over N4. If the SMF is not configured to provide UPF with this information then such UPF reporting filtering is not possible. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.4.5.2 Information flow for subscription to UPF event exposure service for certain UE(s) via SMF | Figure 4.15.4.5.2-1: Subscription to UPF event exposure service for certain UE(s) via SMF
In the case of a group of UEs, the UPF event consumer (e.g. NWDAF) first issues an Nnrf_NFDiscovery_Request service operation to find the UDM providing the target Group ID and gets the NF profile of the UDM serves this group. Then, NWDAF obtains the list of SUPIs that correspond to the Group ID from UDM using Nudm_SDM_Get
NOTE 1: It is assumed that all members of a Group ID belong to the same UDM.
Then, for each SUPI:
1. The UPF event consumer (e.g. NWDAF) invokes Nudm_UECM_Get service operation to retrieve the appropriate SMF by providing UE ID, DNN, S-NSSAI and NF type = SMF.
2. The UDM provides a Nudm_UECM_Get response with the corresponding SMF.
3. The UPF event consumer sends the Nsmf_EventExposure Subscription request to the SMF to subscribe to UPF data, including the following information:
- Notification Target Address (UPF event consumer address), Notification Correlation Information.
- UPF Event Id.
- Event Filter Information, i.e. one or more of the following parameters: S-NSSAI, DNN, DNAI, UPF Id, either Application Id(s) or Traffic Filtering Information, Area of Interest, SSID/BSSID.
- Target of Event Reporting: a UE.
- Reporting suggestion information.
- Type of Measurement and Granularity of Measurement.
If the consumer is NWDAF and the analytic filter information includes application server IP address/FQDN, the NWDAF may need to first obtain the DNAI from NEF as described in steps 2 and 3 in Figure 4.15.4.5.3-1.
4. The SMF selects the PDU session(s) and the UPFs it has to send the request to. The SMF sends the request to the UPF including the UPF event consumer address, UPF Event Id, Notification Correlation Information, Event Filter Information (but only Application Id(s) or Traffic Filtering Information, if received in step 3), Reporting suggestion information, Target of Event Reporting, Type of Measurement and Granularity of Measurement as required. Target of Event Reporting indicates the PDU Session of the UE. The interaction mechanism used between SMF and UPF depends on UPF exposure event and which mechanism applies for each event as described in clause 5.2.26.2.1. For some events, the SMF shall contact UPF (4a) with N4 Session Modification with PFCP (TS 29.244 [69]), for other events (4b) with Nupf_event exposure subscribe request (as defined in clause 5.2.26.2.3).
If an I-SMF is used for this PDU session, and the UPF is controlled by the I-SMF:
- For UPF events for which the SMF-UPF interaction is performed over PFCP (TS 29.244 [69]) (e.g. QoS Monitoring), the corresponding N4 information is sent to I-SMF in Nsmf_PDUSession_Update Request message as described in clause 4.23.5 and I-SMF uses N4 Session Modification (TS 29.244 [69]) towards local UPF (4a).
- For UPF events for which the SMF-UPF interaction is performed using Nupf_EventExposure service, the SMF sends the Nsmf_EventExposure_Subscribe including the UPF event subscription related information to I-SMF, if the I-SMF indicates that the corresponding UPF event is supported by the target UPF. I-SMF forwards the subscription to the target UPF, i.e. local UPF (4b).
NOTE 2: Some events can require SMF interacts with RAN at this stage.
5. Per Reporting suggestion information (if available), the UPF sends the locally collected UPF data by invoking Nupf_EventExposure_Notify service operation to the UPF event consumer. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.4.5.3 Information flow for UPF event exposure service for any UE | Figure 4.15.4.5.3-1: UPF Information Exposure to the UPF event consumer (e.g. NWDAF) of any UE scenario
1. (For the case when the UPF event consumer is NWDAF) The analytics consumer sends a request to the NWDAF for analytics on any UE. The analytics consumer provides the value "any UE" in the Target of Analytics Reporting. Analytics Filter Information optionally contains DNN, S-NSSAI, Area of Interest, Application server IP address/FQDN, Application ID, DNAI, etc.
2. (Optional and only when the UPF event consumer is NWDAF) If the Analytic Filter Information includes application server IP address/FQDN, the NWDAF should first obtain the DNAI from NEF. The NWDAF invokes Nnef_DNAIMapping_Subscribe service to request the DNAI information. The request includes EAS IP/IP range and/or FQDN.
3. (Conditional, if step 2 took place) The NEF determines the suitable DNAI(s) and provides them to NWDAF.
4. The UPF event consumer triggers the SMF(s)/UPF(s) discovery to NRF by Nnrf_NFDiscovery_Request providing the DNN, S-NSSAI and if needed DNAI etc. In deployments with I-SMF, DNAI and/or AoI are not used in the SMF discovery request. Either SMF(s) or UPF(s) are discovered depending on whether the subscription request to UPF events meets the criteria for direct subscription to UPF as defined in clause 5.8.2.17 of TS 23.501 [2]).
5. The NRF provides Nnrf_NFDiscovery_Response that may refer to several SMFs/UPFs.
NOTE 1: In deployments with I-SMF, DNAI and/or AoI are not used for SMF selection.
6. (Option 1) If the subscribed UPF events needs the SMF(s) to do a third-party subscription onto UPF (as defined in clause 5.8.2.17 of TS 23.501 [2]), the procedure as Indirect subscription via several SMFs (steps 3 - 5 in Figure 4.15.4.5.2-1(for single UE)) takes place via each discovered SMF with the difference that the UPF event consumer sets the Target of Event Reporting to "Any UE" and SMF selects PDU sessions and the UPFs it has to send the request to, based on Event Filter Information.
7. (Option 2) If the subscribed UPF events allows to directly subscribe to UPF (as defined in clause 5.8.2.17 of TS 23.501 [2]), the UPF event consumer (e.g. NWDAF) triggers the Nupf_EventExposure_Subscribe to all discovered UPFs. The information included in the subscription is:
- Notification Target Address (UPF event consumer address), Notification Correlation Information.
- UPF Event Id.
- Event Filter Information, i.e. one or more of the following parameters: S-NSSAI, DNN, either Application Id(s) or Traffic Filtering Information.
- Target of Event Reporting: any UE.
- Reporting suggestion information.
- Type of Measurement and Granularity of Measurement.
NOTE 2: As the Target of Event Reporting is "any UE", care needs to be taken with regards to load and major signalling impacts and it is expected that the subscription request contains Event Filter Information and appropriate Event Reporting Information (like Sampling ratio and Partitioning criteria, see Table 4.15.1-1) in order to minimize the UPF performance impact.
8. Each of the UPFs invokes Nupf_EventExposure_Notify service operation directly to the UPF event consumer (e.g. NWDAF). |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.4.5.4 Information flow for subscription via SMF to UPF event exposure service related with AOI | Figure 4.15.4.5.4-1: Subscription to UPF event exposure service for AOI via SMF
If the subscription is related to AOI, the UPF event consumer (e.g. NWDAF) firstly get the UE list which includes the UE(s) located in the AOI from the AMF(s), then subscribe to UPF via SMF as described in clause 4.15.4.5.2. If the UPF event consumer (e.g. NWDAF) further needs to filter certain UE(s) out from the UE list get from the AMF(s), the UPF event consumer (e.g. NWDAF) locally decides the final UE list.
1. The UPF event consumer (e.g. NWDAF) determines the AMF(s) based on the AOI, i.e. TAIs and possibly on the target S-NSSAI and obtains the UE list which includes the UE(s) located in the AoI from AMF(s) by invoking Namf_EventExposure_Subscribe service operation to get the presence of UE(s) and moving in or out status in Area of Interest as described in clause 5.2.2.3 and in clause 5.3.4.4 of TS 23.501 [2]. The target of Namf_EventExposure_Subscribe depends on whether the UPF event consumer (e.g. NWDAF) targets one UE a group of UE or Any UE.
2. The UPF event consumer (e.g. NWDAF) locally computes the final UE list by comparing the UE list from AMF(s) and its own target UE list if it exists.
3. For each UE in the final UE list, the UPF event consumer (e.g. NWDAF) issues a subscription to UPF event exposure service via the SMF serving the UE (Nsmf_EventExposure Subscription) to get UPF data as described in clause 4.15.4.5.2. When an AMF reports a change of the list of UE(s) in the AoI (Namf_EventExposure_Notify), the UPF event consumer (e.g. NWDAF) may need to cancel the Nsmf_EventExposure Subscription or to issue a new Nsmf_EventExposure Subscription. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.4.5.5 Information flow for direct subscription to UPF event exposure service for certain UE using UE's IP address | Figure 4.15.4.5.5-1: Subscription to UPF event exposure service for certain UE(s) directly using UE's IP address
In the case, UPF event consumer (e.g. AF (when in trusted domain) or NEF) is aware of the UE IP address and the UPF Event ID(s) that are to be subscribed meets the criteria for direct subscription to UPF as defined in clause 5.8.2.17 of TS 23.501 [2]), then UPF Event consumer can subscribe to UPF directly for Event Exposure using the following procedure:
1. The UPF event consumer triggers the UPF discovery to NRF by Nnrf_NFDiscovery_Request providing the UE IP address information and optionally the DNN, S-NSSAI, IP domain if IPv4 address is provided. UE IP address provided to NRF maybe the IP address as seen by the DN (e.g. a Public IP address)
2. The NRF responds with Nnrf_NFDiscovery_Response message including the information of UPF for the provided UE IP address.
If step 2 does not include any discovered UPF, the information flow described in clause 4.15.4.5.2 can be used instead.
3. The UPF event consumer sends the Nupf_EventExposure Subscription request for the UPF Event(s) including the following information:
- Notification Target Address (UPF event consumer address), Notification Correlation Information.
- UPF Event Id.
- Event Filter Information, i.e. one or more of the following parameters: S-NSSAI, DNN, either Application Id(s) or Traffic Filtering Information.
- Target of Event Reporting: UE IP address.
- Reporting suggestion information.
- Type of Measurement and Granularity of Measurement.
4. As per the information provided in the previous step, UPF reports the collected data to the UPF event consumer by invoking Nupf_EventExposure Notify.
NOTE: In the case there is a NAT, NAPT (Network Address Port Translation) deployed in UPF, the trusted AF can use the Nupf_GetUEPrivateIPaddrAndIdentifiers service before step 1 to get the private IP address of the UE. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.4.5.6 Information flow for subscription to UPF event exposure service via SMF during UPF relocation and PDU Session release | Figure 4.15.4.5.6-1: Subscription to UPF event exposure service via SMF during UPF relocation and PDU Session release
This information flow is used in the scenario of UPF relocation, e.g. the source UPF is I-UPF or L-PSA which is relocated in SSC mode 1, or the source UPF is PSA UPF which is relocated in SSC mode 3. The information flow also applies to PDU Session release.
When the UPF event consumer targets a specific UE, the procedure is as follows:
1. The UPF event consumer (e.g. NWDAF) subscribes to the UPF data via SMF by invoking Nsmf_EventExposure_Subscribe service operation, and the Target of Event Reporting indicates a specific UE. The consumer may include a Remaining data reporting indication, which indicates how to handle the data collected for that specific event(s) by the source UPF when the N4 session is released (e.g. due to UPF relocation or PDU session release) i.e.either to discard the collected data or send the collected data to the consumer.
2. The SMF selects the source UPF and subscribes to the source UPF by invoking Nupf_EventExposure_Subscribe service operation or via N4 Session Modification, depending on the event. The SMF forwards the Remaining data reporting indication to the source UPF if received in step 1.
3. When the notification event is triggered, the UPF sends the Nupf_EventExposure_Notify service operation to the UPF event consumer, including the locally collected UPF data.
4. The SMF determines that the UPF needs to be relocated or PDU Session needs to be released.
5. In the case of UPF relocation, the SMF initiates a PDU Session update to relocate UPF (for example procedure in clause 4.3.5.3) including N4 session release in source UPF. In the case of PDU Session release, the SMF initiates a PDU Session release procedure, including N4 session release.
6. When (source) UPF terminates the subscription upon release of the UE related N4 Session (step 5), the (source) UPF may send any collected data not yet sent to the UPF event consumer taking into account local configuration and/or the Remaining data reporting indication (if received) for an event(s) from SMF. For example, for periodic reporting type of the UPF event exposure service when the UPF changes, the (source) UPF may report to the consumer any data collected between the time instance of the last notification to the consumer and the time instance of the UPF change. Or for event triggered reporting with Reporting suggestion information, when the UPF changes, the source UPF may report to the consumer any data that has been collected but not sent to the consumer yet.
NOTE: Step 6 takes place as part of step 5. The UPF can send any collected data not yet sent to the UPF event consumer before N4 session is released.
7. In the case of UPF relocation, to continue the subscription of the UPF event consumer, if the UPF related information is matched with the subscription request in step 1, the SMF may select a target UPF and may re-subscribe to the target UPF based on the subscription from UPF event consumer in step 1. Depending on the event, SMF may have sent the subscription to target UPF in step 5 instead.
8. When the notification event is triggered, the UPF sends the Nupf_EventExposure_Notify service operation to the UPF event consumer, including locally collected UPF data.
In the case of PDU Session release, steps 7-8 do not apply.
When the UPF event consumer targets Any UE, the same procedure applies with the following changes:
- In step 1 target is Any UE.
- Step 2 and step 3 are performed for each of the UEs selected by the SMF to serve the request received in step 1.
- Step 4 to step 8 may apply to any of the PDU sessions selected by the SMF to serve the request received in step 1. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.4.5.7 Information flow for subscription directly to UPF event exposure service during N4 session release | Figure 4.15.4.5.7-1: Subscription directly to UPF event exposure service during N4 session release
When the UPF event consumer targets a specific UE, the procedure is as follows:
1. If the subscribed UPF events allows to directly subscribe to UPF (as defined in clause 5.8.2.17 of TS 23.501 [2]), steps 1-2 as described in Figure 4.15.4.5.5-1 are performed.
2. The UPF event consumer (e.g. NWDAF) triggers the Nupf_EventExposure_Subscribe to the discovered UPF, and the Target of Event Reporting contains a single UE identified by the UE IP address. The consumer may include a Remaining data reporting indication for an Event ID(s), which indicates how to handle the data collected for that event(s) by the source UPF when the N4 session of the UPF is released (e.g. due to UPF relocation or PDU session release) i.e. either to discard the collected data or send the collected data to the consumer. The consumer may include a Subscription termination reporting indication requesting the UPF to notify subscription termination to the consumer when N4 session is released.
3. When the notification event is triggered, the UPF invokes Nupf_EventExposure_Notify service operation directly to the UPF event consumer (e.g. NWDAF).
4. When the N4 session corresponding to the UE is released (e.g. the SMF initiates a PDU Session update to relocate UPF including N4 session release in source UPF, or the SMF initiates a PDU Session release procedure including N4 session release), the UPF determines that the subscription to the UPF event has been terminated.
5. If step 2 included Subscription termination reporting indication, the UPF sends a last notification to the UPF event consumer by invoking Nupf_EventExposure_Notify service operation, which includes a subscription termination indication to notify that the subscription to the UPF event(s) has been terminated, and may include a cause code specifying the reason for subscription termination, e.g. N4 session release. If step 2 included Remaining data reporting indication and/or based on local configuration, the UPF may report to the consumer any data for the subscribed event, that has been collected but not sent to the consumer yet.
NOTE 1: N4 session release may be part of UPF relocation within the same PDU Session (see clause 4.3.5.3). The UPF event consumer that knows the new UE IP address allocated to the UE could send a new subscription to the target UPF as described in clause 4.15.4.5.5.
NOTE 2: Step 5 takes place as part of step 4. The UPF can send any collected data not yet sent to the UPF event consumer before N4 session is released.
When the UPF event consumer targets Any UE, the same procedure applies with the following changes:
- In step 2, target is Any UE. The Subscription termination reporting indication does not apply to this case. If included, UPF ignores it.
- Steps 3 to 5 applies for each of the N4 Sessions applicable to the subscription request received in step 2.
- A release of any of the applicable N4 Sessions has no impact on the subscription to the UPF event(s). |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.5 Void | |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6 External Parameter Provisioning | |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.1 General | Provisioning capability allows an external party to provision the information, such as expected UE behaviour and service specific parameters or the 5G VN group information to 5G network functions. In the case of provisioning the expected UE behavioural information, the expected UE behavioural information consists of information on expected UE movement and communication characteristics. In the case of provisioning the 5G VN group information the provisioning information consists of information on 5G VN group. The service specific information consists of information to support the specific service in 5G system. Provisioned data can be used by the other NFs. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.2 NEF service operations information flow | Figure 4.15.6.2-1: Nnef_ParameterProvision_Create / Nnef_ParameterProvision_Update / Nnef_ParameterProvision_Delete request/response operations
0. NF subscribes to UDM notifications of UE and/or Group Subscription data updates. In the UDM subscription, the NF may request to be notified about expected UE behaviour parameter(s) in Table 4.15.6.3-1 or Application-Specific Expected UE Behaviour parameter(s) in Table 4.15.6.3f-1 or CAG Information provisioning parameters in Table 4.15.6.3h-1 that may have been externally provisioned by an AF.
NOTE 1: The NF can subscribe to Group Subscription data from UDM in this step and be notified of Group Subscription data updates in step 7 using the Shared Data feature defined in TS 29.503 [52].
NOTE 2: The external parameters in Table 4.15.6.3-1 may be provisioned by an AF hosting an AI/ML based application.
If an expected UE behaviour parameter subscription is provided by the NF, the subscription may include a threshold indicating that certain confidence and/or accuracy levels must be met for the parameter(s) to be notified by the UDM to the NF. Meeting the threshold condition may mean that the confidence and/or accuracy levels of a parameter are equal to certain threshold, or less than certain threshold, or greater than certain threshold, or less than or equal to certain threshold, or greater than or equal to certain threshold. The threshold may be in the form of a range (e.g. minimum value to maximum value, where each may be inclusive or exclusive) or a specific value.
NOTE 3: The threshold may be used to e.g. prevent certain Expected UE Behaviour parameters from being stored in the network when certain minimum level of confidence and/or accuracy are not met.
NOTE 4: Confidence level indicates a probability assertion for the associated Expected UE Behaviour parameter and accuracy level indicates the performance of the estimator (e.g. AI/ML model) used for the prediction.
0b. [Conditional, on using NWDAF-assisted values] The AF may subscribe to NWDAF via NEF in order to learn the UE mobility analytics and/or UE Communication analytics for a UE or group of UEs by applying the procedure specified in clause 6.1.1.2 of TS 23.288 [50]. The Analytics ID is set to any of the values specified in clause 6.7.1 of TS 23.288 [50].
0c. [Conditional, on using NWDAF-assisted values] AF validates the received data and derives any of the Expected UE behaviour parameters defined in clause 4.15.6.3 for a UE or group of UEs.
1. The AF provides one or more parameter(s) to be created or updated, or deleted in a Nnef_ParameterProvision_Create or Nnef_ParameterProvision_Update or Nnef_ParameterProvision_Delete Request to the NEF. The parameters(s) may include corresponding confidence and/or accuracy levels.
The AF provides target UE identifier (e.g. GPSI or External Group ID) as described in clause 5.2.6.4. The Transaction Reference ID identifies the transaction request between NEF and AF. For the case of Nnef_ParameterProvision_Create, The NEF assigns a Transaction Reference ID to the Nnef_ParameterProvision_Create request.
NEF checks whether the requestor is allowed to perform the requested service operation by checking requestor's identifier (i.e. AF Identifier).
NOTE 5: When multiple AF parameter provisioning Create or Update requests with different values of the same Expected UE Behaviour parameters are received from different AFs, the network behaviour is unspecified.
For a Create request associated with a 5G VN group, the External Group ID identifies the 5G VN Group.
The payload of the Nnef_ParameterProvision_Update Request includes one or more of the following parameters:
- Expected UE Behaviour parameters (see clause 4.15.6.3); or
- Network Configuration parameters (see clause 4.15.6.3a); or
- 5G VN group data (i.e. 5G VN configuration parameters) (see clause 4.15.6.3b), or
- 5G VN group membership management parameters (see clause 4.15.6.3c); or
- Location Privacy Indication parameters of the "LCS privacy" Data Subset of the Subscription Data (see clause 5.2.3.3.1 of the present document and clause 7.1 of TS 23.273 [51]); or
- Ranging/Sidelink Positioning Indication parameters of the "Ranging/Sidelink Positioning privacy" Data Subset of the Subscription Data (see clause 5.2.3.3.1 of the present document and Annex B of TS 33.533 [94]); or
- MTC Provider Information; or
- AF provided ECS Address Configuration Information (see clause 4.15.6.3d); or
- DNN and S-NSSAI specific Group Parameters (see clause 4.15.6.3e); or
- Application-Specific Expected UE Behaviour parameters (see clause 4.15.6.3f); or
- CAG Information provisioning parameters (see clause 4.15.6.3h); or
- Static IP address assignment parameters (see clause 4.15.6.3i);
- Provisioning of Non-3GPP Device Identifier(s) Information (see clause 4.15.6.15).
The AF may request to delete 5G VN configuration by sending Nnef_ParameterProvision_Delete to the NEF.
2. If the AF is authorised by the NEF to provision the parameters, the NEF requests to create, update and store, or delete the provisioned parameters as part of the subscriber data via Nudm_ParameterProvision_Create, Nudm_ParameterProvision_Update or Nudm_ParameterProvision_Delete Request message, the message includes the provisioned data and NEF reference ID and optionally MTC Provider Information.
If the AF is not authorised to provision the parameters, then the NEF continues in step 6 indicating the reason to failure in Nnef_ParameterProvision_Create/Update/Delete Response message. Step 7 does not apply in this case.
If the AF has requested IP address assignment provisioning parameters and the AF is only allowed for a certain IP address/prefix range for the target DNN and D-NSSAI, the NEF checks whether the requested parameters are allowed. If the request is not allowed, the NEF responds to the AF including an appropriate failure reason in the step 6. In this case step 7 does not apply.
NOTE 6: The allowed IP address/prefix range, DNN and S-NSSAI for the Static IP address assignment can be locally configured at the NEF.
If the NEF did not receive DNN and/or S-NSSAI from the AF and such information is configured as needed within 5GC, the NEF determines the DNN and/or S-NSSAI from the AF Identifier.
If the AF provides the DNN and S-NSSAI specific Group Parameters, the AF shall indicate the External Group ID, targeted DNN and S-NSSAI in the request.
If the AF provides the service area in the form of geographical information, the NEF maps the geographical information to the list of TAs.
NOTE 7: For non-roaming case and no authorisation or validation by the UDM required and if the request is not associated with a 5G VN group, the NEF can directly forward the external parameter to the UDR via Nudr_DM_Update Request message. And in this case, the UDR responds to NEF via Nudr_DM_Update Response message.
3. UDM may read from UDR, by means of Nudr_DM_Query, corresponding subscription information in order to validate required data updates and authorize these changes for this subscriber or Group for the corresponding AF.
Based on local configuration, UDM may determine if there is any requirement in terms of threshold conditions that need to be met by the provisioned parameter before storing the parameter in UDR. If there are no such requirement(s) or the requirement(s) are satisfied, UDM may proceed seamlessly. If not satisfied, step 5 is triggered as a failed procedure and a related cause value is provided, e.g. "confidence level not sufficient". In that case step 4 is skipped.
4. If the AF is authorised by the UDM to provision the parameters for this subscriber, the UDM resolves the GPSI to SUPI and requests to create, update or delete the provisioned parameters as part of the subscriber data via Nudr_DM_Create/Update/Delete Request message, the message includes the provisioned data.
If a new 5G VN group is created, the UDM shall assign a unique Internal Group ID for the 5G VN group and include the newly assigned Internal Group ID in the Nudr_DM_Create Request message. If the list of 5G VN group members is changed or if 5G VN group data has changed, the UDM updates the UE and/or Group subscription data according to the AF/NEF request.
When the service area is configured or updated for a group, the UDM authorises the request.
If the Default QoS is configured or updated for a group, the UDM authorises the request and uses such Default QoS to set 5GS Subscribed QoS profile in Session Management Subscription data for each UE within the group. The 5GS Subscribed QoS profile in Session Management Subscription data will be considered by SMF as described in clause 5.7.2.7 of TS 23.501 [2].
If the Static IP address assignment parameters is created, updated or removed by the AF, the UDM authorises the request and adds, updates or removes such static IP address/prefix in Session Management Subscription data for the UE. The static IP address information in Session Management Subscription data will be considered by SMF as described in clause 5.8.2.2.1 of TS 23.501 [2].
UDR stores the provisioned data as part of the UE and/or Group subscription data and responds with Nudr_DM_Create/Update/Delete Response message.
If the Maximum Group Data Rate is configured or updated for a 5G VN group, the UDM authorises the request and the Maximum Group Data Rate is applied as described in clause 5.29.2 of TS 23.501 [2].
When the 5G VN group data (as described in clause 4.15.6.3b) or 5G VN group membership is updated, the UDR notifies to the subscribed PCF by sending Nudr_DM_Notify as defined in clause 4.16.12.2.
If CAG Information is created, updated or removed by the AF as described in clause 4.15.6.3h, the UDM authorises the request and adds, updates or removes such CAG information in Access and Mobility Subscription data for the UE.
If the AF is not authorised to provision the parameters, then the UDM continues in step 5 indicating the reason to failure in Nudm_ParameterProvision_Update Response message and step 7 is not executed.
The UDM classifies the received parameters (i.e. Expected UE Behaviour parameters or Suggested Number of Downlink Packets or the 5G VN configuration parameters or DNN and S-NSSAI specific Group Parameters or Location Privacy Indication parameters or ECS Address Configuration Information or Static IP address assignment parameters or CAG Information provisioning parameters), into AMF associated and SMF associated parameters. The UDM may use the AF Identifier received from the NEF in step 2 to relate the received parameter with a particular subscribed DNN and/or S-NSSAI. The UDM stores the SMF-Associated parameters under corresponding Session Management Subscription data type.
Each parameter or parameter set may be associated with a validity time. The validity time is stored at the UDM/UDR and in each of the NFs, to which parameters are provisioned (e.g. in AMF or SMF). Upon expiration of the validity time, each node deletes the parameters autonomously without explicit signalling.
If the ECS Address Configuration Information is provided to any UE in AF request, the UDM shall make use of the shared data mechanism defined in TS 29.503 [52] and notify all NFs (SMFs) that have subscribed to receiving such shared data change notifications.
5. UDM responds the request with Nudm_ParameterProvision_Create/Update/Delete Response. If the procedure failed, the cause value indicates the reason.
6. NEF responds the request with Nnef_ParameterProvision_Create/Update/Delete Response. If the procedure failed, the cause value indicates the reason.
NOTE 8: If AF receives a failure update notification due to threshold conditions not met and AF does not want NFs to keep using the old parameters, then AF can send an Nnef_ParameterProvision_Delete request.
7. [Conditional this step occurs only after successful step 4] UDM notifies the subscribed Network Function of the updated UE and/or Group subscription data via Nudm_SDM_Notification Notify message.
a) If the subscribed NF is AMF, the UDM performs Nudm_SDM_Notification (SUPI or Internal Group Identifier, AMF-Associated Expected UE Behaviour parameters, Subscribed Periodic Registration Timer, subscribed Active Time, 5G VN group data or DNN and S-NSSAI specific Group Parameters, UE allowed CAG list and its time validity information, etc.) service operation. If the AMF receives confidence and/or accuracy levels along the Expected UE behaviour parameter(s), the AMF may use the associated confidence level and/or accuracy level when handling the expected UE behaviour parameter(s). The AMF uses the received parameters to derive the appropriate UE configuration of the NAS parameters and to derive Core Network assisted RAN parameters. The AMF may determine a Registration area based on parameters Stationary indication or Expected UE Moving Trajectory.
If the AMF obtains service area for a group or SUPI, the AMF configures the DNN for the group as LADN DNN and applies the LADN per DNN and S-NSSAI taking into account the service area for the group as described in clause 5.6.5a of TS 23.501 [2].
b) If the subscribed NF is SMF, the UDM performs Nudm_SDM_Notification (SUPI or Internal Group Identifier, SMF-Associated Expected UE Behaviour parameter set, DNN/S-NSSAI, Suggested Number of Downlink Packets, 5G VN group data, Session Management Subscription data, etc.) service operation.
The SMF stores the received parameters and associates them with a PDU Session based on the DNN and S-NSSAI included in the message from UDM.
- If the SMF is notified by UDM that the subscription data has changed, and SMF detects that the static IP address/prefix is added, removed or updated, the SMF may perform the PDU Session release procedure and includes a cause value indicating that a PDU Session re-establishment is requested, as described in clause 4.3.4 and in clause 5.8.2.2.1 of TS 23.501 [2].
If the SMF receives confidence and/or accuracy levels along the Expected UE behaviour parameter(s), the SMF may use the associated confidence level and/or accuracy level when handling the expected UE behaviour parameter(s). The SMF may use the parameters as follows:
- SMF configures the UPF accordingly. The SMF can use the Scheduled Communication Type parameter or Suggested Number of Downlink Packets parameter to configure the UPF with how many downlink packets to buffer. The SMF may use Communication duration time parameter and/or Expected Inactivity Time parameter and/or Battery Indication parameter combined with their confidence and/or accuracy levels to set the inactivity timer for a PDU Session. The SMF then waits for a UP inactivity report to be received from UPF. Based on the received UP inactivity report, the SMF may determine to deactivate the corresponding UP connection associated to the PDU Session of a single UE or determine a collective pattern of deactivating UP connections for multiple UEs (e.g. for a group of UEs receiving application AI/ML traffic during FL operation) and perform CN-initiated selective deactivation of UP connection of an existing PDU Session.
- The SMF may derive SMF derived CN assisted RAN information for the PDU Session. The SMF provides the SMF derived CN assisted RAN information to the AMF as described in PDU Session establishment procedure or PDU Session modification procedure.
NOTE 9: The NEF (in NOTE 1) or the UDM (in step 3) can also update the corresponding UDR data via Nudr_DM_Create/Delete as appropriate.
NOTE 10: The change of AF provided ECS configuration information is not meant to apply immediately: the UDM interface to the SMF can refer to Shared Data for the Subscription provided ECS configuration information.
NOTE 11: Specification details of confidence and accuracy levels are left to Stage 3 work. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.3 Expected UE Behaviour parameters | These Expected UE Behaviour parameters characterise the foreseen behaviour of a UE or a group of UEs. Sets of these parameters may be provided via the NEF to be stored as part of the subscriber data. Each parameter within the Expected UE Behaviour shall have an associated validity time. The validity time indicates when the Expected UE Behaviour parameter expires and shall be deleted by the related NFs. The validity time may be set to indicate that the particular Expected UE Behaviour parameter has no expiration time. When the validity time expires, the related NFs delete their local copy of the associated Expected UE Behaviour parameter(s). In addition, each parameter within the Expected UE Behaviour may have a confidence and/or accuracy level associated with it. The confidence level indicates a probability assertion for the associated Expected UE Behaviour parameter and the accuracy level indicates the performance of the estimator (e.g. AI/ML model) used for the prediction. The provision procedure of the Expected UE Behaviour is realized by external parameter provision procedure defined in clause 4.15.6.2.
The Expected UE Behaviour parameters stored as AMF-Associated Expected UE Behaviour parameters which is per UE level and SMF-Associated Expected UE Behaviour parameters which is per PDU session level in UDM. AMF retrieves the AMF-Associated Expected UE Behaviour parameters from UDM which may related to both PDU session(s) and SMS transmission. SMF retrieves the SMF-Associated Expected UE Behaviour parameters from UDM for the specific PDU session. AMF and SMF uses the Expected UE Behaviour parameters as described in clause 5.4.6.2 of TS 23.501 [2].
Table 4.15.6.3-1: Description of Expected UE Behaviour parameters
Expected UE Behaviour parameter
Description
Expected UE Moving Trajectory
Identifies the UE's expected geographical movement
Example: A planned path of movement
Stationary Indication
Identifies whether the UE is stationary or mobile [optional]
Communication Duration Time
Indicates for how long the UE will normally stay in CM-CONNECTED for data transmission.
Example: 5 minutes.
[optional]
Periodic Time
Interval Time of periodic communication
Example: every hour.
[optional]
Scheduled Communication Time
Time and day of the week when the UE is available for communication.
Example: Time: 13:00-20:00, Day: Monday.
[optional]
Battery Indication
Identifies power consumption criticality for the UE: if the UE is battery powered with not rechargeable/not replaceable battery, battery powered with rechargeable/replaceable battery, or not battery powered.
[optional]
Traffic Profile
Identifies the type of data transmission: single packet transmission (UL or DL), dual packet transmission (UL with subsequent DL or DL with subsequent UL), multiple packets transmission
[optional]
Scheduled Communication Type
Indicates that the Scheduled Communication Type is Downlink only or Uplink only or Bi-directional [To be used together with Scheduled Communication Time]
Example: <Scheduled Communication Time>, DL only.
[optional]
Expected Time and Day of Week in Trajectory
Identifies the time and day of week when the UE is expected to be at each location included in the Expected UE Moving Trajectory.
[optional]
The Expected UE Moving Trajectory and the Expected Time and Day of Week in Trajectory may be used by the AMF. All other parameters may be used by the AMF and by the SMF.
The Scheduled Communication Type and the Traffic Profile should not be used by the AMF to release the UE when NAS Release Assistance Information from the UE is available.
In the case of NB-IoT UEs, the parameters may be forwarded to the RAN to allow optimisation of Uu resource allocation for NB-IoT UE differentiation.
4.15.6.3a Network Configuration parameters
The Network Configuration parameters are the parameters sent from an AF by invoking the Nnef_ParameterProvision Service as described in clause 4.15.6.2.
The Network Configuration parameters are described in Table 4.15.6.3a-1.
Table 4.15.6.3a-1: Description of Network Configuration parameters
Network Configuration parameter
Description
Maximum Response Time
Identifies the time for which the UE stays reachable to allow the AF to reliably deliver the required downlink data.
[optional]
Maximum Latency
Identifies maximum delay acceptable for downlink data transfers.
Example: in order of 1 minute to multiple hours.
[optional]
Suggested Number of Downlink Packets
Identifies the number of packets that the core network is suggested to buffer if the UE is not reachable.
Example: 5 packets.
[optional]
MPS for Messaging indication
Sets(Enables)/Clears(Disables) the MPS priority handling for Messaging service of the UE.
The parameters Maximum Response Time and Maximum Latency are stored in the UDM and the Maximum Response Time is sent to the AMF for event monitoring as specified in 4.15.3.2.3b.
The AMF may use the Maximum Response Time parameter as guide to configure:
- Extended Connected time for MICO mode;
- when to send reachability notifications to AF relative to expected reachability events (e.g. paging occasions).
If the UDM received multiple Network Configuration requests, the UDM shall accept the request as long as the Maximum Latency (if received) and/or the Maximum Response Time (if received) are within the range defined by operator policies. The UDM shall use the minimum value of Maximum Latency(s) to derive the subscribed periodic registration timer and use the maximum value of Maximum Response Time(s) to derive the subscribed Active Time as specified in step 2 of clause 4.15.3.2.3b. If the newly derived value is changed comparing to the one last time sent to the AMF, the UDM notify the AMF of the updated value via Nudm_SDM_Notification message. If there is a deletion of Network Configuration request, the UDM re-calculates the values (see step 2 in clause 4.15.3.2.3b) and notify the AMF if needed.
The Suggested Number of Downlink Packets is classified as SMF associated subscription data. If the NEF is providing DNN and S-NSSAI as specified in clause 4.15.3.2.3, then the UDM is able to associate the parameters with subscribed DNN and S-NSSAI and provides the Suggested Number of Downlink Packets consolidated as specified in 4.15.3.2.3b to the SMF for the PDU Session associated with the specific DNN and S-NSSAI as specified in clause 4.15.6.2. The SMF may use the Suggested Number of Downlink Packets parameter to configure the number of packets to buffer in the SMF/UPF (in the case of UPF anchored PDU sessions) or in the NEF (in the case of NEF anchored PDU session) when the UE is not reachable and extended buffering of downlink data is activated.
The MPS for Messaging indication sets(enables)/clears(disables) the MPS treatment of messaging service for MPS-subscribed UE. The parameter is stored in UDM/UDR and provided to NFs and entities involved in the messaging service (i.e. SMS over NAS, SMS over IP and messaging over IMS are all controlled by one indication) as part of the subscription data. The MPS for Messaging indication is used in communications between NFs and network entities in CN and is not delivered to UE. The detailed MPS for Messaging indication handling is further specified in clause 4.13 for SMS over NAS, in TS 23.204 [96] for SMS over IP, and in TS 23.228 [52] for messaging over IMS.
A Validity Time may be associated with any of the Network Configuration parameters. When the validity time expires, the related NFs delete their local copy of the associated Network Configuration parameter(s). If the deletion results in subscribed value change, the UDM shall notify the AMF or SMF of the changed value.
4.15.6.3b 5G VN group data
The 5G VN group data is described in Table 4.15.6.3b-1.
Table 4.15.6.3b-1: Description of 5G VN group data
Parameters
Description
DNN
DNN for the 5G VN group.
S-NSSAI
S-NSSAI for the 5G VN group.
PDU Session Type
PDU Session Types allowed for 5G VN group.
Application descriptor
There may be multiple instances of this information; this information may be used to build URSP sent to 5G VN group members (NOTE 1).
Information related with secondary authentication / authorization
This may indicate:
- the need for secondary authentication/authorization (as defined in clause 5.6 of TS 23.501 [2]);
- the need for SMF to request the UE IP address from the DN-AAA Server.
If at least one of secondary authentication/authorization or DN-AAA UE IP address allocation is needed, the AF may provide DN-AAA Server addressing information.
5G VN group communication indication
Indicates that the 5G VN group is associated with 5G VN group communication.
Maximum Group Data Rate
This limits the total bit rate that is expected to be provided across all sessions of a 5G VN group.
[optional].
User Plane Security Policy
User Plane Security Policy for PDU sessions associated with the 5G VN group.
NOTE 1: As described in TS 23.503 [20], the PCF may be configured with a mapping from Application Descriptor to other information required to construct the URSP rules, e.g. IP filters and SSC mode.
The information described in Table 4.15.6.3b-1 corresponds to 5G VN group data that an AF may provide together with External Group ID.
4.15.6.3c 5G VN Group membership management parameters
5G VN group membership management parameters that an AF may provide are described in Table 4.15.6.3c-1.
Table 4.15.6.3c-1: Description of 5G VN Group membership management parameters
Parameters
Description
List of GPSI
List of 5G VN Group members, each member is identified by GPSI
External Group ID
A identifier for 5G VN group
4.15.6.3d ECS Address Configuration Information Parameters
AF provided ECS Address Configuration Information that an AF may provide to the 5GC is described in Table 4.15.6.3d-1. The AF may associate ECS Address Configuration Information with a group of UE or with any UE.
Multiple AF may configure 5GC with AF provided ECS Address Configuration Information.
The Subscription provided ECS Address Configuration Information that a SMF may receive is described in Table 4.15.6.3d-2
For non-roaming and LBO cases, the ECS Address Configuration Information is provided to SMF as Session Management Subscription data. The ECS Address Configuration Information is associated with a DNN and S-NSSAI included in the message from UDM.
For HR cases:
- When the HPLMN has the knowledge of EACI in the VPLMN, the ECS Address Configuration Information is provided to H-SMF as Session Management Subscription data. The ECS Address Configuration Information is associated with a DNN, S-NSSAI and PLMN ID included in the message from UDM.
- When the HPLMN does not have the knowledge of EACI in the VPLMN, for this scenario, as defined in clauses 6.5.2.6.2 and 6.5.2.6.3 of 23.548 [74], V-NEF stores the VPLMN EACI received from AF deployed in the VPLMN in V-UDR as Application data. The ECS Address Configuration Information for this case is associated with DNN, S-NSSAI and any UE.
The SMF is not expected to understand the internal structure of ECS Address Configuration Information.
Table 4.15.6.3d-1: Description of ECS Address Configuration Information provided by the AF
Parameters
Description
ECS Address Configuration Information
One or more ECS Configuration Information as defined in clause 8.3.2.1 of TS 23.558 [83].
Target
This may correspond to one of:
- a group of UE identified by an external group Id (for non-roaming, LBO and HR case when HPLMN has the knowledge of EACI in the VPLMN);
- any UE.
PLMN ID
The ECS Address Configuration Information is applied to the UE roaming in target PLMN.
Table 4.15.6.3d-2: Description of Subscription provided ECS Address Configuration Information (as sent to the SMF)
Parameters
Description
ECS Address Configuration Information
As defined in Table 4.15.6.3d-1. The SMF is not expected to understand the internal structure of ECS Address Configuration Information.
4.15.6.3e DNN and S-NSSAI specific Group Parameters
The DNN and S-NSSAI specific Group Parameters are the parameters sent from an AF by invoking the Nnef_ParameterProvision Service as described in clause 4.15.6.2.
The DNN and S-NSSAI specific Group Parameters are described in Table 4.15.6.3e-1.
Table 4.15.6.3e-1: Description of DNN and S-NSSAI specific Group Parameters
Parameters
Description
Default QoS (NOTE 1)
Identifies the requested default QoS parameters (as defined in clause 5.7.2.7 of TS 23.501 [2]) applicable to each UE within a group.
[optional]
Service Area (NOTE 1)
Identifies the AF-requested Service Area applicable to each UE within a group.
[optional]
NOTE 1: These parameters are applicable per DNN and S-NSSAI.
4.15.6.3f Application-Specific Expected UE Behaviour parameters
The Application-Specific Expected UE Behaviour parameters characterise the foreseen behaviour of a UE for a specific application. When AF provisions the Application-Specific Expected UE Behaviour parameters, the AF shall provide application traffic descriptors (i.e. the corresponding Packet Filters or Application ID). Each parameter within the Application-Specific Expected UE Behaviour shall have an associated validity time and may have a confidence and/or accuracy level associated with it as defined in the clause 4.15.6.2 and clause 4.15.6.3.
Table 4.15.6.3f-1: Description of Application-Specific Expected UE Behaviour parameters
Application-Specific Expected UE Behaviour Parameters
Description
Expected PDU session Inactivity Time
Identifies the expected PDU Session Inactivity time during which the UE will not have traffic related to the application.
4.15.6.3g Network Slice Usage Control parameters for dedicated S-NSSAI to a single AF
An AF having a S-NSSAI dedicated to it may be authorized, to control the parameters to remove the S-NSSAI from the Allowed NSSAI or release a PDU Session associated with the S-NSSAI. In this case, these parameters may be provided by an authorized AF via the NEF and be stored as part of the subscriber data. The provision procedure of the Network Slice Usage Control Parameters is realized by external parameter provision procedure as described in clause 4.15.6.2. The AMF and SMF use the Network Slice Usage Control parameter as described in clause 5.15.15 of TS 23.501 [2].
Table 4.15.6.3g-1: Description of Network Slice Usage Control parameters
Network Slice Usage Control parameter
Description
For each indicated S-NSSAI
S-NSSAI
S-NSSAI for which the inactivity-based slice control applies (NOTE 1)
slice deregistration inactivity timer value
For network slice usage control, this timer identifies the wait time before deregistering the UE from the S-NSSAI by removing the S-NSSAI from the Allowed NSSAI when no associated PDU Session is established with the indicated S-NSSAI.
[optional]
PDU Session inactivity timer value
Identifies the wait time to release the PDU Session associated with the indicated S-NSSAI when there is no data transmission
[optional]
NOTE 1: This slice is solely dedicated for one authorized AF and not shared with other AFs.
According to the received network slice usage control parameter, the UDM updates all related UE subscription data which includes the indicated S-NSSAI.
Only in this case and for subscribers having such an S-NSSAI as a subscribed S-NSSAI, the slice deregistration inactivity timer value and/or PDU Session inactivity timer value is obtained by the AMF or SMF as part of the subscription data respectively as specified in clauses 4.2.2.2.2 and 4.3.2.2.1.
4.15.6.3h CAG Information Provisioning parameters
The CAG Information Provisioning parameters are the parameters as listed in Table 4.15.6.3h-1 to be sent from an AF by invoking the Nnef_ParameterProvision Service as described in clause 4.15.6.2. The AF request can be driven by the CAG owner or an authorized administrator. The NEF updates the UDM with the CAG Information Provisioning parameters received from the AF. The UDM updates the allowed CAG list and time validity information, if available, of the given UE(s) and notifies AMF via Nudm_SDM_Notification Notify message as defined in clause 4.15.6.2. Then, AMF initiates UE Configuration Update procedure to the UE(s) to update the allowed CAG list of the UE(s) along with the provided time validity information as described in clause 4.2.4.2.
NOTE: The existing CAG concept defined for PNI-NPN in 5.30.3.3 of TS 23.501 [2] is re-used for CAG Information Provisioning parameters.
Table 4.15.6.3h-1: Description of CAG Information Provisioning parameters
CAG Information Provisioning parameters
Description
UE ID(s)
Indicates the unique identifier for the user to be updated with provided CAG information. It can be GPSI.
CAG ID(s)
Indicates the CAG ID(s) to be included to the existing UE Allowed CAG list.
time validity information
Indicates the expiry time if the CAG information is only valid temporarily. If no expiry time is present, the provided CAG information will be valid until the next update is performed.
4.15.6.3i Static IP address assignment parameters
An AF may be authorized to provide static IP address(es) per subscriber for a given DNN and S-NSSAI. In this case, the static IP address for a GPSI may be provided by an authorized AF via the NEF and be stored as part of the UE subscriber data. The provision procedure for static IP addresses is realized by external parameter provision procedure as described in clause 4.15.6.2. The AF may provide a GPSI and include the static IP address/prefix for that GPSI, as described in Table 4.15.6.3i-1. The SMF uses the static UE IP address as described in clause 5.8.2.2 of TS 23.501 [2].
NOTE: It is assumed that the IP address/prefix range, DNN and S-NSSAI that can be used by the AF is agreed as part of an SLA.
Table 4.15.6.3i-1: Description of Static IP address assignment parameters
Parameters
Description
GPSI
GPSI for which the IP address/prefix applies.
DNN
DNN for which the IP address information applies.
S-NSSAI
S-NSSAI for which the IP address information applies.
IP address
Indicates one static UE IPv4 address or one IPv6 prefix or both, for the subscriber identified by GPSI. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.4 Set a chargeable party at AF session setup | Figure 4.15.6.4-1: Set the chargeable party at AF session set-up
1. When setting up the connection between an ASP sponsoring a session and the UE, the ASP may communicate with the AF to request to become the chargeable party for the session to be set up by sending a Nnef_ChargeableParty_Create request message (AF Identifier, UE address, Flow description information or External Application Identifier, Sponsor Information, Sponsoring Status, Background Data Transfer Reference ID, DNN, S-NSSAI) to the NEF. The Sponsoring Status indicates whether sponsoring is started or stopped, i.e. whether the 3rd party service provider is the chargeable party or not. The Background Data Transfer Reference ID parameter identifies a previously negotiated transfer policy for background data transfer as defined in clause 4.16.7. The NEF assigns a Transaction Reference ID to the Nnef_ChargeableParty_Create request.
2. The NEF authorizes the AF request to sponsor the application traffic and stores the sponsor information together with the AF Identifier and the Transaction Reference ID. If the authorisation is not granted, step 2 is skipped and the NEF replies to the AF with a Result value indicating that the authorisation failed.
NOTE: Based on operator configuration, the NEF may skip this step. In this case the authorization is performed by the PCF in step 3.
3. The NEF interacts with the PCF by triggering a Npcf_PolicyAuthorization_Create request message and provides IP filter information or Ethernet filter information, sponsored data connectivity information (as defined in TS 23.503 [20]), Background Data Transfer Reference ID (if received from the AF) and Sponsoring Status (if received from the AF) to the PCF.
4. The PCF determines whether the request is allowed and notifies the NEF if the request is not authorized. If the request is not authorized, NEF responds to the AF in step 5 with a Result value indicating that the authorization failed.
5. The NEF sends a Nnef_ChargeableParty_Create response message (Transaction Reference ID, Result) to the AF. Result indicates whether the request is granted or not. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.5 Change the chargeable party during the session | Figure 4.15.6.5-1: Change the chargeable party during the session
1. For the ongoing AF session, the AF may send a Nnef_ChargeableParty_Update request message (AF Identifier, Transaction Reference ID, Sponsoring Status, Background Data Transfer Reference ID) to the NEF. The Sponsoring Status indicates whether sponsoring is enabled or disabled, i.e. whether the 3rd party service provider is the chargeable party or not. The Background Data Transfer Reference ID parameter identifies a previously negotiated transfer policy for background data transfer as defined in clause 4.16.7. The Transaction Reference ID provided in the Change chargeable party request message is set to the Transaction Reference ID that was assigned, by the NEF, to the a Nnef_ChargeableParty_Create request.
2. The NEF authorizes the AF request of changing the chargeable party. If the authorisation is not granted, step 3 is skipped and the NEF replies to the AF with a Result value indicating that the authorisation failed.
NOTE: Based on operator configuration, the NEF may skip this step. In this case the authorization is performed by the PCF in step 3.
3. The NEF interacts with the PCF by triggering a Npcf_PolicyAuthorization_Update request and provides IP filter information or Ethernet filter information, sponsored data connectivity information (as defined in TS 23.503 [20]), Background Data Transfer Reference ID (if received from the AF) and Sponsoring Status (if received from the AF) to the PCF.
4. The PCF determines whether the request is allowed and notifies the NEF if the request is not authorized. If the request is not authorized, NEF responds to the AF in step 5 with a Result value indicating that the authorization failed.
5. The NEF sends a Nnef_ChargeableParty_Update response message (Transaction Reference ID, Result) to the AF. Result indicates whether the request is granted or not. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.6 Setting up an AF session with required QoS procedure | Figure 4.15.6.6-1: Setting up an AF session with required QoS procedure
1. The AF sends a request to reserve resources for an AF session using Nnef_AFsessionWithQoS_Create request message (UE address, AF Identifier, Flow description information or External Application Identifier, QoS Reference or individual QoS parameters, Alternative Service Requirements (as described in clause 6.1.3.22 of TS 23.503 [20]), DNN, S-NSSAI) to the NEF. Optionally, QoS monitoring requirements, Indication of ECN marking for L4S, Data Burst Size Marking Support Indication, Time to Next Burst Support Indication, PDU Set QoS Parameters (as described in clause 5.7.7 of TS 23.501 [2]) and Protocol Description (as described in clauses 5.37.5, 5.37.8.3 and 5.37.10 of TS 23.501 [2]) and/or On-path N6 Signalling Information (see clause 5.37.9 of TS 23.501 [2]) can be included in the AF request. For Expedited Transfer with reflective QoS, the AF may provide two media flows associated with different QoS requirements and different Expedited Transfer Indication values, as described in clause 6.1.3.27.9 of TS 23.503 [20]. For a Multi-modal service, the AF may provide a Multi-modal Service ID together with Multi-modal Service Requirements information for each data flow, as described in clause 6.1.3.27.3 of TS 23.503 [20]. Optionally, a period of time or a traffic volume for the requested QoS can be included in the AF request. The AF may, instead of a QoS Reference, provide one or more of the following individual QoS parameters: Requested 5GS Delay (optional), Requested Priority (optional), Requested Guaranteed Bitrate, Requested Maximum Bitrate, Maximum Burst Size and Requested Packet Error Rate. The AF may also provide an Averaging Window value for deriving such parameters for GBR QoS Flows. Regardless of whether the AF request is formulated using a QoS Reference or individual QoS parameters, the AF may also provide one or more of the following parameters that describe the traffic characteristics: flow direction, Burst Arrival Time at UE (uplink) or UPF (downlink), Periodicity, Time domain, Survival Time, Capability for BAT adaptation or BAT Window, Periodicity Range. The AF may also provide an RT Latency Indication. The optional Alternative Service Requirements provided by the AF shall either contain QoS References or Requested Alternative QoS Parameter Set(s) in a prioritized order as described in clause 6.1.3.22 of TS 23.503 [20]. Optionally, Packet Delay Variation requirements can be included in the AF request as described in clause 6.1.3.26 of TS 23.503 [20]. Optionally, the AF may provide QoS duration and QoS inactivity interval in order to indicate PCF the time period when the QoS should be applied. The AF may include (S)RTP Multiplexed Media Identification Information in the Flow Description and separate service requirements per media flow and request differentiated QoS handling for media flows multiplexed into a single UDP/IP traffic flow as described in clause 6.1.3.27.7 of TS 23.503 [20].
NOTE 1: For multi-modal flows related to multiple UEs, multiple UE-specific AF requests are used and the AF provided information to NEF is the same as single UE case (as defined in clause 5.37.2 of TS 23.501 [2]).
2. The NEF authorizes the AF request that contains a single UE address and may apply policies to control the overall amount of QoS authorized for the AF. If the authorisation is not granted, all steps (except step 5) are skipped and the NEF replies to the AF with a Result value indicating that the authorisation failed. The NEF assigns a Transaction Reference ID to the Nnef_AFsessionWithQoS_Create request.
The NEF determines whether to invoke the TSCTSF or to directly contact the PCF based on operator configuration. This determination may use the presence of a QoS Reference or individual QoS parameters in the AF request. The determination may also use the AF identifier or the presence of AF provided parameters that describe the traffic characteristics in the AF request.
NOTE 2: The determination can also be based on an SLA between operator and application provider, e.g. using the DNN/S-NSSAI for the AF session according to the SLA.
If the NEF determines not to invoke the TSCTSF, then steps 3, 4, 5, 6, 7, 8 are executed, otherwise, steps 3a, 3b, 4a, 4b, 5, 6a, 7a, 7b, 8 are executed.
3. If the NEF determines to contact the PCF directly without invoking the TSCTSF, the NEF uses the UE address to discover the PCF from the BSF. The NEF forwards received parameters to the PCF in the Npcf_PolicyAuthorization_Create request. Any optionally received period of time or traffic volume mapped and forwarded as sponsored data connectivity information (as defined in TS 23.503 [20]).
If the AF is considered to be trusted by the operator, the AF uses the Npcf_PolicyAuthorization_Create request message to interact directly with PCF to request reserving resources for an AF session.
3a. If the NEF determines to invoke the TSCTSF, the NEF forwards received parameters in the Ntsctsf_QoSandTSCAssistance_Create request message to the TSCTSF. Any optionally received period of time or traffic volume is mapped and forwarded as sponsored data connectivity information (as defined in TS 23.503 [20]).
If the AF is considered to be trusted by the operator, the AF uses the Ntsctsf_QoSandTSCAssistance_Create request message to interact directly with TSCTSF to request reserving resources for an AF session.
A TSCTSF address may be locally configured (a single TSCTSF per DNN/S-NSSAI) in the NEF, PCF and trusted AF. Alternatively, the NEF uses the AF Identifier to determine the DNN/S-NSSAI and uses the DNN/S-NSSAI to discover the TSCTSF from the NRF.
3b. The TSCTSF determines whether it has an AF session with a PCF for the given UE address. In this case the TSCTSF sends a Npcf_PolicyAuthorization_Update request message to the PCF and forwards the received parameters after executing the adjustment and mapping actions described below.
If the TSCTSF does not have an AF-session for a given UE address, the TSCTSF discovers the PCF and a Npcf_PolicyAuthorization_Create request message to the PCF.
If the TSCTSF receives a Requested 5GS Delay, the TSCTSF calculates a Requested PDB by subtracting the UE-DS-TT Residence Time (either provided by the PCF or pre-configured at TSCTSF) from the Requested 5GS Delay and sends the Requested PDB to the PCF instead of the Requested 5GS Delay. If the TSCTSF receives any of the following parameters: flow direction, Burst Arrival Time, Periodicity, Time domain, Survival Time, Capability for BAT adaptation or BAT Window, Periodicity Range from the NEF, the TSCTSF determines the TSC Assistance Container and sends it to the PCF instead of these parameters.
4. For requests received from the NEF in step 3, the PCF determines whether the request is authorized and notifies the NEF if the request is not authorized.
If the request is authorized, the PCF derives the required QoS parameters of the PCC rule based on the information provided by the NEF and determines whether this QoS is allowed (according to the PCF configuration) and notifies the result to the NEF. If the AF is considered to be trusted by the operator, the PCF sends the Npcf_PolicyAuthorization_Create response message directly to AF.
If the PCF receives the individual QoS parameters instead of QoS Reference, the PCF determines a 5QI that matches the individual QoS parameters as described in clause 6.1.3.22 of TS 23.503 [20]. It also sets the GBR and MBR for the PCC rule according to the requested values. The PCF may use the Requested Priority from the AF to determine Priority Level as defined in clause 5.7.3.3 of TS 23.501 [2]. Requested individual QoS parameter values supersede default values for the 5QI.
If the PCF receives (S)RTP Multiplexed Media Identification Information with different QoS parameters or QoS Reference, the PCF may generate PCC rules as described in clause 6.1.3.27.7 of TS 23.503 [20].
If the PCF receives the RT Latency Indication described in clause 6.1.3.22 of TS 23.503 [20], the PCF executes Uplink-Downlink Transmission Coordination as described in clause 5.37.7 of TS 23.501 [2] and the associated QoS monitoring for the two correlated QoS Flows as described in clause 6.1.3.27.2 of TS 23.503 [20].
If the PCF receives PDU Set QoS parameters described in clause 5.7.7 of TS 23.501 [2], the PDU Set QoS parameters are applied as described in clause 6.1.3.22 of TS 23.503 [20].
If the PCF receives an explicit indication (i.e. Indication of ECN marking for L4S) as described in clause 6.1.3.22 of TS 23.503 [20], PCF decides that the service data flow supports ECN marking for L4S. PCF then indicates to the SMF to enable ECN marking for L4S for that QoS flow.
In addition, if the Alternative Service Requirements are provided, the PCF derives the Alternative QoS parameter set(s) in the same way from the one or more QoS Reference parameters or the Requested Alternative QoS Parameter Set(s) contained in the Alternative Service Requirements keeping the same prioritized order (as defined in clause 6.1.3.22 of TS 23.503 [20]).
NOTE 3: The PCF derived Alternative QoS parameter set(s) for the PCC rule are subsequently used to establish Alternative QoS Profile(s). The Alternative QoS Profile parameters provided to the NG-RAN are specified in clause 5.7.1.2a of TS 23.501 [2].
For multi-modal flows, the PCF derives the required QoS parameters in the PCC rules and generates the QoS monitoring requirements policy for each media flow, based on the information provided by the NEF.
If the PCF determines that the SMF needs updated policy information, the PCF issues a Npcf_SMPolicyControl_UpdateNotify request with updated policy information about the PDU Session as described in the PCF initiated SM Policy Association Modification procedure in clause 4.16.5.2.
4a. For requests received from the TSCTSF in step 3b, the PCF determines whether the request is authorized and notifies the TSCTSF if the request is not authorized.
If the request is authorized, the PCF derives the required QoS parameters of the PCC rule in the same way it is described in step 4 based on the information provided by the TSCTSF and determines whether this QoS is allowed (according to the PCF configuration) and notifies the result to the TSCTSF.
If the PCF determines that the SMF needs updated policy information, the PCF issues a Npcf_SMPolicyControl_UpdateNotify request with updated policy information about the PDU Session as described in the PCF initiated SM Policy Association Modification procedure in clause 4.16.5.2.
If the PCF receives a subscription for the 5GS Bridge/Router information from the TSCTSF, if the PCF does not have the 5GS Bridge/Router information for the PDU Session, the PCF uses the PCF initiated SM Policy Association Modification procedure as described in clause 4.16.5.2 to subscribe for 5GS Bridge/Router information event from the SMF. Once the PCF has the 5GS Bridge/Router information, the PCF notifies the TSCTSF for the 5GS Bridge/Router information (including the UE-DS-TT Residence Time).
4b. The TSCTSF sends a Ntsctsf_QoSandTSCAssistance_Create response message (Transaction Reference ID, Result) to the NEF. Result indicates whether the request is granted or not.
If the AF is considered to be trusted by the operator, the TSCTSF sends the Ntsctsf_QoSandTSCAssistance_Create response message directly to AF.
5. The NEF sends a Nnef_AFsessionWithQoS_Create response message (Transaction Reference ID, Result) to the AF. Result indicates whether the request is granted or not.
6. The NEF shall send a Npcf_PolicyAuthorization_Subscribe message to the PCF to subscribe to notifications of Resource allocation status and may subscribe to other events described in clause 6.1.3.18 of TS 23.503 [20].
6a. The TSCTSF shall send a Npcf_PolicyAuthorization_Subscribe message to the PCF to subscribe to notifications of Resource allocation status and may subscribe to other events described in clause 6.1.3.18 of TS 23.503 [20].
The TSCTSF that receives Capability for BAT adaptation or BAT Window in step 3a shall subscribe to notification on BAT offset via sending a Npcf_PolicyAuthorization_Subscribe request message to the PCF.
7. When the event condition is met, e.g. that the establishment of the transmission resources corresponding to the QoS update succeeded or failed, the PCF sends Npcf_PolicyAuthorization_Notify message to the NEF notifying about the event.
If the AF is considered to be trusted by the operator, the PCF sends the Npcf_PolicyAuthorization_Notify message directly to AF.
7a. When the event condition is met, e.g. that the establishment of the transmission resources corresponding to the QoS update succeeded or failed, the PCF sends Npcf_PolicyAuthorization_Notify message to the TSCTSF notifying about the event.
7b. The TSCTSF sends Ntsctsf_QoSandTSCAssistance_Notify message with the event reported by the PCF to the NEF.
If the AF is considered to be trusted by the operator, the TSCTSF sends the Ntsctsf_QoSandTSCAssistance_Notify message directly to AF.
8. The NEF sends Nnef_AFsessionWithQoS_Notify message with the event reported by the PCF to the AF.
The AF may send Nnef_AFsessionWithQoS_Revoke request to NEF in order to revoke the AF request. The NEF authorizes the revoke request and triggers the Ntsctsf_QoSandTSCAssistance_Delete and/or Npcf_PolicyAuthorization_Delete service operations for the AF request.
4.15.6.6a AF session with required QoS update procedure
Figure 4.15.6.6a-1: AF session with required QoS update procedure
1. For an established AF session with required QoS, the AF may send a Nnef_AFsessionWithQoS_Update request message (AF Identifier, Transaction Reference ID, [Flow description information], [QoS Reference or individual QoS parameters], [Alternative Service Requirements (as described in clause 6.1.3.22 of TS 23.503 [20])]) to NEF for updating the reserved resources. Optionally, Indication of ECN marking for L4S, Data Burst Size Marking Support Indication, Time to Next Burst Support Indication, PDU Set QoS Parameters (as described in clause 5.7.7 of TS 23.501 [2]) and Protocol Description (as described in clauses 5.37.5, 5.37.8.3, 5.37.9.2, 5.37.9.4 and other (sub)clauses in clause 5.37 of TS 23.501 [2]) and/or On-pathN6 Signalling Information (see clause 5.37.9 of TS 23.501 [2]) can be included in the AF request. For Expedited Transfer with reflective QoS (as described in clause 5.37.10.2 of TS 23.501 [2]), the AF may provide two media flows associated with different QoS requirements and different Expedited Transfer Indication values, as described in clause 6.1.3.27.9 of TS 23.503 [20]. For a Multi-modal service, the AF may provide/update Multi-modal Service Requirements information of the existing data flows as described in clause 6.1.3.27.3 of TS 23.503 [20]. Optionally, a period of time or a traffic volume for the requested QoS can be included in the AF request. The Transaction Reference ID provided in the AF session with required QoS update request message is set to the Transaction Reference ID that was assigned, by the NEF, to the Nnef_AFsessionWithQoS_Create request message. The AF may, instead of a QoS Reference, provide one or more of the following individual QoS parameters: Requested 5GS Delay (optional), Requested Priority (optional), Requested Guaranteed Bitrate, Requested Maximum Bitrate, Maximum Burst Size and Requested Packet Error Rate. The AF may also provide an Averaging Window. Regardless whether the AF request is formulated using a QoS Reference or individual QoS parameters, the AF may also provide one or more of the following parameters that describe the traffic characteristics: flow direction, Burst Arrival Time at UE (uplink) or UPF (downlink), Periodicity, Time domain, Survival Time, Capability for BAT adaptation or BAT Window, Periodicity Range. The optional Alternative Service Requirements provided by the AF shall either contain QoS References or Requested Alternative QoS Parameter Set(s) in a prioritized order as specified in clause 6.1.3.22 of TS 23.503 [20]. Optionally, Packet Delay Variation requirements can be included in the AF request as described in clause 6.1.3.26 of TS 23.503 [20]. The AF may include (S)RTP Multiplexed Media Identification Information in the Flow Description and separate service requirements per media flow and requests for differentiated QoS handling for media flows multiplexed into a single UDP/IP traffic flow as described in clause 6.1.3.27.7 of TS 23.503 [20].
2. The NEF authorizes the AF request of updating AF session with required QoS and may apply policies to control the overall amount of QoS authorized for the AF. If the authorisation is not granted, all steps (except step 5) are skipped and the NEF replies to the AF with a Result value indicating that the authorisation failed.
3. The NEF shall contact the same NF type (i.e. TSCTSF or PCF) as with the initial Nnef_AFsessionWithQoS_Create request during the establishment procedure in clause 4.15.6.6. If the NEF determined not to invoke the TSCTSF, then steps 3, 4, 5, 6, 7 are executed, otherwise, steps 3a, 3b, 4a, 4b, 5, 6a, 6b, 7 are executed. If the Nnef_AfsessionWithQoS_Update adds any parameters that would require the NEF to invoke TSCTSF while the NEF determined not to invoke the TSCTSF for the initial Nnef_AFsessionWithQoS_Create request, the NEF shall reject the Nnef_AFsessionWithQoS_Update request with a cause value indicating the reason of failure.
If the NEF does not invoke the TSCTSF, the NEF interacts with the PCF by triggering a Npcf_PolicyAuthorization_Update request and forwards received parameters to the PCF. Any optionally received period of time or traffic volume is mapped and forwarded as sponsored data connectivity information (as defined in TS 23.503 [20]).
If the AF is considered to be trusted by the operator, the AF uses the Npcf_PolicyAuthorization_Update request message to interact directly with PCF to update the reserving resources for an AF session.
3a. If the NEF decided to contact the TSCTSF when the session was established, the NEF forwards received parameters in the Ntsctsf_QoSandTSCAssistance_Update request message to the TSCTSF. Any optionally received period of time or traffic volume is mapped and forwarded as sponsored data connectivity information (as defined in TS 23.503 [20]).
If the AF is considered to be trusted by the operator, the AF uses the Ntsctsf_QoSandTSCAssistance_Update request message to interact directly with TSCTSF to update the reserving resources for an AF session.
3b. The TSCTSF interacts with the PCF by triggering a Npcf_PolicyAuthorization_Update request and forwards the received parameters after executing the adjustment and mapping actions described in step 3b of clause 4.15.6.6.
4. The PCF processes the Npcf_PolicyAuthorization_Update request according to the actions described in step 4 of clause 4.15.6.6.
4a. The PCF processes the Npcf_PolicyAuthorization_Update request according to the actions described in step 4a of clause 4.15.6.6. If the PCF has received a request to unsubscribe for 5GS Bridge/Router information Notification, the PCF uses the PCF initiated SM Policy Association Modification procedure as described in clause 4.16.5.2 to unsubscribe for 5GS Bridge/Router information event from the SMF.
4b. The TSCTSF sends a Ntsctsf_QoSandTSCAssistance_Update response message (Transaction Reference ID, Result) to the NEF. Result indicates whether the request is granted or not.
If the AF is considered to be trusted by the operator, the TSCTSF sends the Ntsctsf_QoSandTSCAssistance_Update response message directly to AF.
5. The NEF sends a Nnef_AFsessionWithQoS_Update response message (Transaction Reference ID, Result) to the AF. Result indicates whether the request is granted or not.
6. The PCF sends Npcf_PolicyAuthorization_Notify message to the NEF when the modification of the transmission resources corresponding to the QoS update succeeded or failed, or when an Alternative Service Requirement is being applied.
If the AF is considered to be trusted by the operator, the PCF sends the Npcf_PolicyAuthorization_Notify message directly to AF.
6a. The PCF sends Npcf_PolicyAuthorization_Notify message to the TSCTSF when the modification of the transmission resources corresponding to the QoS update succeeded or failed, or when an Alternative Service Requirement is being applied.
6b. The TSCTSF sends Ntsctsf_QoSandTSCAssistance_Notify message with the event reported by the PCF to the NEF.
If the AF is considered to be trusted by the operator, the TSCTSF sends the Ntsctsf_QoSandTSCAssistance_Notify message directly to the AF.
7. The NEF sends Nnef_AFsessionWithQoS_Notify message with the event reported by the PCF to the AF. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.7 Service specific parameter provisioning | |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.7.1 General | This clause describes the procedures for enabling the AF to provide service specific parameters to 5G system via NEF.
The AF may issue requests on behalf of applications not owned by the PLMN serving the UE.
NOTE 1: In the case of architecture without CAPIF support, the AF is locally configured with the API termination points for the service. In the case of architecture with CAPIF support, the AF obtains the service API information from the CAPIF core function via the Availability of service APIs event notification or Service Discover Response as specified in TS 23.222 [54].
The AF request sent to the NEF contains the information as below:
1) Service Description.
Service Description is the information to identify a service the Service Parameters are applied to. The Service Description in the AF request can be represented by the combination of DNN and S-NSSAI, an AF-Service-Identifier or an External Application Identifier.
2) Service Parameters.
Service Parameters are the service specific information which needs to be provisioned in the Network and delivered to the UE in order to support the service identified by the Service Description.
VPLMN ID(s) that indicates the PLMN(s) where the AF guidance on URSP determination and all its RSD(s), applies.
3) Target UE(s) or a group of UEs or PLMN ID(s) of inbound roamers.
Target UE(s) or a group of UEs or PLMN ID(s) of inbound roamers indicate the UE(s) who the Service Parameters shall be delivered to. Individual UEs can be identified by GPSI, or an IP address/Prefix or a MAC address. Groups of UEs are identified by an External Group Identifiers as defined in TS 23.682 [23]. If identifiers of target UE(s) or a group of UEs or PLMN ID(s) of inbound roamers are not provided, then the Service Parameters shall be delivered to any UEs of the PLMN of the NEF using the service identified by the Service Description.
4) Subscription to events.
The AF may subscribe to notifications about the outcome of the UE Policies delivery due to service specific parameter provisioning.
The NEF authorizes the AF request received from the AF and stores the information in the UDR as "Application Data". The Service Parameters are delivered to the targeted UE by the PCF when the UE is reachable. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.7.2 Service specific parameter provisioning by AF to HPLMN | Figure 4.15.6.7.2-1 shows procedure for service specific parameter provisioning. The AF uses Nnef_ServiceParameter service to provide the service specific parameters to the HPLMN and the UE. In the roaming case, PCF is replaced by H-PCF, the AMF interacts with the V-PCF which interacts with H-PCF.
Figure 4.15.6.7.2-1: Service specific information provisioning by AF to HPLMN
0a. The AMF establishes UE Policy Association as specified in clause 4.16.11.
0b. PCF requests notifications from the UDR on changes in UE policy information.
1. To create a new request, the AF invokes an Nnef_ServiceParameter_Create service operation. The request may include subscription information to the report of the outcome of UE Policy delivery.
To update or remove an existing request, the AF invokes an Nnef_ServiceParameter_Update or Nnef_ServiceParameter_Delete service operation together with the corresponding Transaction Reference ID which was provided to the AF in Nnef_ServiceParameter_Create response message.
The content of this service operation (AF request) includes the information described in clause 5.2.6.11.
2. The AF sends its request to the NEF. The NEF authorizes the AF request. The NEF may perform the following:
- Map the AF-Service-Identifier into DNN and S-NSSAI combination, determined by local configuration, if required by the service and not provided in Service Parameters.
- Map the External Application Identifier into the corresponding Application Identifier known in the core network.
2a. The NEF may invoke Nudm_SDM_Get service operation to perform the following mappings:
- Map the GPSI in Target UE Identifier into SUPI, according to information received from UDM.
- Map the External Group Identifier in Target UE Identifier into Internal Group Identifier, according to information received from UDM.
If the AF subscribed to the outcome of UE Policy delivery, the AF indicates where the AF receives the corresponding notifications.
(in the case of Nnef_ServiceParameter_Create): The NEF assigns a Transaction Reference ID to the Nnef_ServiceParameter_Create request.
2b. (in the case of Nnef_ServiceParameter_Create or Update): The NEF may need to authorize the service specific parameter provisioning request with the UDM by sending a Nudm_ServiceSpecificAuthorisation_Create service operation as defined in clause 4.15.6.7a.
NOTE 2: The NEF skips the mapping of GPSI or External Group Identifier in step 2a if it needs to authorize the service specific parameter provisioning request with the UDM as the response of the authorization request from UDM includes the SUPI or Internal Group Identifier.
(in the case of Nnef_ServiceParameter_delete): The NEF requests the UDM to remove the authorization of the service specific parameters provisioned by sending a Nudm_ServiceSpecificAuthorisation_Remove service operation.
3. (in the case of Nnef_ServiceParameter_Create or Update): The NEF stores the AF request information in the UDR as the "Application Data" (Data Subset setting to "Service specific information") together with the assigned Transaction Reference ID.
(in the case of Nnef_ServiceParameter_delete): The NEF deletes the AF request information from the UDR.
4. The NEF responds to the AF. In the case of Nnef_ServiceParameter_Create response message, the response message includes the assigned Transaction Reference ID.
If the UE is registered to the network and the PCF performs the subscription to notification to the data modified in the UDR by invoking Nudr_DM_Subscribe (AF service parameter provisioning information, SUPI, Data Set setting to "Application Data", Data Subset setting to "Service specific information") at step 0, the following steps are performed:
5. The PCF(s) receive(s) a Nudr_DM_Notify notification of data change from the UDR. The PCF checks whether application guidance on URSP determination applies for the SUPI as specified in clause 6.1.3.18 of TS 23.503 [20], if this check fails the PCF notifies the failure with an appropriate cause and no delivery of UE Policies to the UE is performed.
NOTE 3: PCF does not have to subscribe for each UE the application specific information, e.g. if PCF has already received the application specific information for a group of UE or for a DNN by a subscription of other UE. The same application specific information is delivered to every UE in a group or a DNN.
For PIN service, PCF generates the URSP rules with PIN ID in the Traffic Descriptor as specified in Table 6.6.2.1-2 of TS 23.503 [20].
6. The PCF initiates UE Policy delivery as specified in clause 4.2.4.3.
7. If the AF subscribed to notifications about the outcome of UE Policies delivery due to Service specific parameter provisioning and the PCF is notified of UE Policy Container from the AMF, the PCF notifies the UE Policy delivery result contained in the UE Policy container as the outcome of the procedure to NEF by sending Npcf_EventExposure_Notify including the SUPI, the list of GPSI(s) if available, and if provided in the step 2a, the Internal-Group-Id.
If the PCF is notified about UE Policy delivery failure from the AMF due to UE not reachable, the PCF may determine to retry step 6 of this procedure when the UE becomes reachable. In such a case, the PCF may report the interim status i.e. UE is temporarily unreachable as the outcome of the procedure to NEF by sending Npcf_EventExposoure_Notify.
If the PCF determines the failure of the UE Policies delivery procedure, the PCF notifies the failure with an appropriate cause such as UE is unreachable, DNN not authorized as the outcome of the procedure to NEF by sending Npcf_EventExposure_Notify.
If the PCF determines that it cannot yet deliver URSP Rules that are based on the service parameters from the AF, then the PCF may report in the interim status that URSP Rules have not yet been delivered by the PCF as the outcome of the procedure to NEF by sending Npcf_EventExposure_Notify.
The content of event reporting in this step is described in clause 6.1.3.18 of TS 23.503 [20].
8. When the NEF receives Npcf_EventExposure_Notify, the NEF performs information mapping (e.g. AF Transaction Internal ID provided in Notification Correlation ID to AF Transaction ID, SUPI to GPSI, Internal-Group-Id to External-Group-Id, etc.) and triggers the appropriate Nnef_ServiceParameter_Notify message. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.7.3 Service specific parameter provisioning by AF to VPLMN | Figure 4.15.6.7.3-1 shows procedure for service specific parameter provisioning by the AF to VPLMN.
Figure 4.15.6.7.3-1: Service specific information provisioning by AF to VPLMN
0a. Same as in step 0a of Figure 4.15.6.7.2-1.
0b-0c. The V-PCF may request to V-UDR on changes in UE policy information and H-PCF may subscribe to H-UDR.
1-2. Steps 1-2 of Figure 4.15.6.7.2-1 apply with the following differences:
- The AF and NEF belong to the VPLMN. The AF may belong to third party with agreement with VPLMN.
- When the AF provides application guidance on URSP Rule determination to the VPLMN, it will target "PLMN ID(s) of inbound roamers". The NEF in the VPLMN rejects any request for a GPSI or an External-Group-ID of a different PLMN.
3-5. Steps 3-5 of Figure 4.15.6.7.2-1 apply with the following differences:
- AF, NEF and UDR belong to VPLMN. The AF may belong to third party with agreement with VPLMN.
- The UDR in the VPLMN notifies the V-PCF(s) that have subscribed to the reception of application guidance on URSP determination.
- In step 5, the V-PCF receives updates on application guidance on URSP determination for the PLMN ID of a SUPI that has a UE Policy Association established. The PLMN ID of the SUPI is included in the target "PLMN ID(s) of inbound roamers" in step 2. In this case, the V-PCF checks whether application guidance on URSP determination applies for the SUPI as specified in clause 6.1.2.2.4 of TS 23.503 [20], if this check fails, step 7 and step 8 follow, the V-PCF notifies the failure with an appropriate cause such as e.g. DNN not authorized..
5a. The V-PCF sends the Service Parameters including the mapped HPLMN S-NSSAI values to the H-PCF and subscribes to the result of the delivery of UE Policies if the delivery result was requested by the AF, using the event reporting on "Notification on outcome of UE Policies delivery" described in clause 6.1.3.18 of TS 23.503 [20].
NOTE: The AMF determines whether LBO is allowed and performs SMF selection to select the SMF in VPLMN for LBO case as described in clause 6.3.2 of TS 23.501 [2].
The H-PCF requests V-PCF to notify the result of UE policy delivery to the UE.
6. The H-PCF generates new or updated URSP Rules considering the Service Parameters received from the V-PCF in step 5a as specified in clause 6.1.2.2.4 of TS 23.503 [20].
7-8. Steps 7-8 of Figure 4.15.6.7.2-1 apply with the following differences:
- Notification is sent from V-PCF to the AF belonging to the VPLMN or third party with agreement with VPLMN.
4.15.6.7a Authorization of service specific parameter provisioning
Figure 4.15.6.7a-1 shows the procedure to authorize the service specific parameter provisioning requests (e.g. for Application guidance for URSP determination as defined in clause 4.15.6.10).
Figure 4.15.6.7a-1: Service Specific Authorization for an individual UE or group of UEs
1. The AF initiates the procedure as specified in clause 4.15.6.7.
2. The NEF sends Nudm_ServiceSpecificAuthorisation_Create Request including the GPSI or External Group Id, S-NSSAI/DNN, service type, (optional) AF ID, (optional) MTC Provider Information and notification address to receive updates of the authorization from UDM.
3. The UDM maps the GPSI or External Group Id included in the request from the NEF to SUPI or Internal Group Id.
If the request is for an individual UE, the UDM checks the list of subscribed/allowed S-NSSAI/DNNs for the UE and other service info (e.g. MTC provider is authorized for the UE).
If the request is for a group of UEs, the UDM checks whether the group related data (e.g. DNN/S-NSSAI group related data, see table 4.15.6.3b-1) and other service info, e.g. MTC provider is authorized for the group.
4. The UDM responds to the NEF with the service authorization result. If authorization succeeds, the UDM includes the SUPI or Internal Group Id mapping the GPSI or External Group Id provided by the NEF.
If authorization fails (e.g. DNN is not subscribed for the UE or it is different from the group related data, UE subscription or group related data does not allow to modify URSP rules dynamically by an AF or by such specific AF or MTC provider), UDM returns a negative response with an appropriate error code and the NEF rejects the request with the proper error code to inform the AF about the request not authorized.
NOTE 1: The MTC Provider Information can be used by any type of Service Providers (MTC or non-MTC) or Corporate or External Parties for, e.g. to distinguish their different customers.
5. The procedure continues as specified in clause 4.15.6.7.
Figure 4.15.6.7a-2 illustrates the procedure for updating or revoking an existing Service Specific Authorization.
Figure 4.15.6.7a-2: Service Specific Authorization Update procedure
0. UDM provided a successful authorization for a request to provision service specific parameters as defined in Figure 4.15.6.7a-1. The authorization for the provisioning of the service specific parameters is modified in UDM (e.g. due to subscription withdrawal or to the DNN associated to the authorization being removed from UE subscription).
1. The UDM sends a Nudm_ServiceSpecificAuthorisation_UpdateNotify Request (GPSI or External Group Id, SUPI or Internal Group Id, S-NSSAI, DNN, Service Type, (optional) AF ID, (optional) MTC Provider Information, Status, Cause) message to the NEF to update a UE's or group of UEs' authorization.
2. The NEF sends Nudm_ServiceSpecificAuthorisation_UpdateNotify Response message to the UDM to acknowledge the authorization update.
3. If the authorization is revoked, the NEF removes the service specific parameters from the UDR.
4. The NEF informs the AF that the service parameters authorisation status has changed by sending Nnef_ServiceParameter_Notify Request (GPSI or External Group Id, TLTRI, Status, Cause) message to the AF to update the authorization.
5. The AF responds to the NEF with Nnef_ServiceParameter_Notify Response message. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.8 Set a policy for a future AF session | Figure 4.15.6.8-1: Set a policy for a future AF session
1. The AF previously negotiated policy for background data transfer using the Procedure for future background data transfer as described in clause 4.16.7.2.
2. The AF requests that the previously negotiated policy for background data transfer be applied to a group of UE(s) or any UE, by invoking the Nnef_ApplyPolicy_Create service operation (AF Identifier, External Identifier or External Group Identifier, Background Data Transfer Reference ID). The Background Data Transfer Reference ID parameter identifies a previously negotiated transfer policy for background data transfer as defined in clause 4.16.7. The NEF assigns a Transaction Reference ID to the Nnef_ApplyPolicy_Create request. The NEF authorizes the AF request and stores the AF Identifier and the Transaction Reference ID.
3. The NEF invokes Nudm_SDM_Get (Identifier Translation, GPSI) to resolve the GPSI (External Identifier) to a SUPI or the NEF requests to resolve the External Group Identifier into the Internal Group Identifier using Nudm_SDM_Get (Group Identifier Translation, External Group Identifier).
4a. The NEF stores the AF request information in the UDR (Data Set = Application Data; Data Subset = Background Data Transfer, Data Key = Internal Group Identifier or SUPI).
4b. The NEF responds to the Nnef_ApplyPolicy_Create Request (Transaction Reference ID).
5. The PCF(s) that have subscribed to modifications of AF requests (Data Set = Application Data; Data Subset = Background Data Transfer, Data Key = Internal Group Identifier or SUPI) receive(s) a Nudr_DM_Notify notification of data change from the UDR. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.9 Procedures for AF-triggered dynamically changing access and mobility management policies | |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.9.1 General | Access and mobility management policies may be modified due to several inputs including the AF as described in clause 4.16.2. Clause 4.15.6.9 describes the procedures for triggering such modifications in scenarios belonging to "case B" of clause 4.16.2.0 that are initiated by the AF.
The following cases can be distinguished:
- AF requests targeting an individual UE (identified by its SUPI or GPSI) without conditions related to the application traffic; these requests are routed (by the AF or by the NEF) to the PCF for the UE as described in clause 6.2.1.6 of TS 23.503 [20], This case is described in clause 4.15.6.9.2.
- AF requests targeting an individual UE (identified by its GPSI), a group of UEs (identified by an Internal Group Identifier or an External Group Identifier), any UE accessing a combination of DNN and S-NSSAI, or any UE, or any inbound roaming UEs identified by their home PLMN ID(s) using an application identified by an External Application Identifier. For such requests the AF shall contact the NEF and the NEF stores the AF request information in the UDR. The PCF(s) receive a corresponding notification if they had subscribed to the creation / modification / deletion of the AF request information corresponding to UDR Data Keys / Data Sub-Keys. The AF is not aware if the target UEs are with or without an already established AM Policy Association and with or without ongoing PDU Sessions. This case is described in clause 4.15.6.9.3.
NOTE: "any UE" refers to the UEs within the PLMN of the NEF. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.9.2 Processing AF requests to influence access and mobility management policies targeting an individual UE | This procedure is used for individual UEs when the request shall be applied independently of conditions related to the application traffic. Depending on the AF deployment (see clause 6.2.10 of TS 23.501 [2]), the AF may interact with NFs of the Core Network either directly or via the NEF. The procedure for the direct case is described in Figure 4.15.6.9.2‑1, while the procedure for the NEF-mediated case is described in Figure 4.15.6.9.2-2.
Figure 4.15.6.9.2-1: Handling an AF request targeting an individual UE without using NEF
This procedure concerns only non-roaming scenarios, i.e. to cases where the involved entities serving the UE (AF, PCF, BSF, AMF) belong to the home PLMN.
1. An AM Policy Association is established for a UE as described in clause 4.16.1.
2a. The AF searches the PCF for the UE using Nbsf_Management_Subscribe with SUPI or GPSI as input, indicating that it is searching for the PCF that handles the AM Policy Association of the UE.
2b. The BSF provides to the AF the identity of the PCF for the UE for the requested SUPI or GPSI via an Nbsf_Management_Notify operation. If a matching entry already exists in the BSF when step 2a is performed, this shall be immediately reported to the AF.
2c. The AF sends to the PCF for the UE its request for influencing the access and mobility management policy of the UE (identified by SUPI or GPSI) using Npcf_AMPolicyAuthorization (optionally providing a timer on how long this policy shall last, in which case the system behaviour upon expiration of this timer is as specified in TS 23.503 [20]). This may include information for AF-requested network slice replacement i.e. an Alternative S-NSSAI for a Replaced S-NSSAI (see clause 5.15.5.2.2a of TS 23.501 [2]), As part of the Npcf_AMPolicyAuthorization request, the AF may subscribe (within the Create and Update operations) or unsubscribe (within the Delete operation) to relevant events specified in clause 6.1.3.18 of TS 23.503 [20], e.g. events related to change of service area coverage.
3. The PCF takes a policy decision and then an AM Policy Association Modification procedure initiated by the PCF for the UE may be performed as described in clause 4.16.2.2. If the AF has subscribed to access and mobility management related events (i.e. request for service area coverage outcome) in step 2, the PCF reports the event (i.e. outcome of the request for service area coverage) to the AF.
Figure 4.15.6.9.2-2: Handling an AF request targeting an individual UE using NEF
This procedure concerns only non-roaming scenarios, i.e. to cases where the involved entities serving the UE (AF, NEF, PCF, BSF, AMF) belong to the home PLMN, or the AF belongs to a third party with which the home PLMN has an agreement.
1. An AM Policy Association is established for a UE as described in clause 4.16.1.
2a. The AF sends to NEF its request for influencing the access and mobility management policy of the UE (identified by GPSI) using Nnef_AMPolicyAuthorization (optionally providing a timer on how long this policy shall last, in which case the system behaviour upon expiration of this timer is as specified in TS 23.503 [20]). As part of the Nnef_AMPolicyAuthorization request, the AF may request to subscribe (within the Create and Update operations) or unsubscribe (within the Delete operation) for relevant events specified in clause 6.1.3.18 of TS 23.503 [20], e.g. events for request for service area coverage outcome. The NEF stores the request and sends a response to the AF. In this message, the AF may request the network slice replacement by providing a slice replacement requirement defined by a pair (Replaced AF-Service-Identifier, Alternative AF-Service-Identifier) to the NEF and the NEF may map the AF-Service-Identifiers to Replaced S-NSSAI and Alternative S-NSSAI (see clause 5.15.5.2.2a of TS 23.501 [2]).
2b. The NEF searches the PCF for the UE using Nbsf_Management_Subscribe with SUPI as input parameter, indicating that it is searching for the PCF that handles the AM Policy Association of the UE.
2c. The BSF provides to the NEF the identity of the PCF for the UE for the requested SUPI via an Nbsf_Management_Notify operation. If a matching entry already exists in the BSF when step 2b is performed, this shall be immediately reported to the NEF.
2d. The NEF sends to PCF for the UE the request for influencing the access and mobility management policy of the UE (identified by SUPI) using Npcf_AMPolicyAuthorization (having potentially translated GPSI to SUPI via UDM). This may include information for AF-requested network slice replacement i.e. an Alternative S-NSSAI for a Replaced S-NSSAI (see clause 5.15.5.2.2a of TS 23.501 [2]). As part of the Npcf_AMPolicyAuthorization request, the NEF may subscribe or unsubscribe (according to what the AF requested in step 2a) for relevant events specified in clause 6.1.3.18 of TS 23.503 [20], e.g. events for change of service area coverage.
2e. The NEF informs the AF about events to which the AF has potentially subscribed (i.e. events for change of service area coverage) using Nnef_AMPolicyAuthorization_Notify.
3. The PCF takes a policy decision and then an AM Policy Association Modification procedure initiated by the PCF for the UE may be performed as described in clause 4.16.2.2. If the AF has subscribed to access and mobility management related events i.e. request for service area coverage outcome in step 2, then the PCF reports the event (i.e. outcome of the request for service area coverage) to the AF as described in clause 4.16.2.2. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.9.3 Processing AF requests to influence access and mobility management policies | With this procedure, the AF can provide its request to influence access and mobility management policies (for one or multiple UEs) at any time.
Figure 4.15.6.9.3-1: Handling an AF request to influence access and mobility management policies Policy
This procedure concerns non-roaming scenarios, i.e. to cases where the involved entities serving the UE (i.e. AF, NEF, PCF, BSF, UDR, AMF) belong to the home PLMN, or the AF belongs to a third party with which the home PLMN has an agreement. This procedure concerns also the local breakout roaming case where the involved entities (i.e. AF, NEF, PCF, BSF, UDR, AMF) serving the UE belong to the VPLMN or the AF belongs to a third party with which the VPLMN has an agreement.
The PCF for the UE and the PCF for the PDU Session can be the same entity, then step 5 is not performed and the PCF itself determines the start/stop of application traffic or SM policy establishment/termination for a DNN, S-NSSAI and proceeds with step 6.
1. AM Policy Association establishment as described in clause 4.16.1.
2. The PCF for the UE may subscribe to policy data related to AM influence (Data Set = Application Data; Data Subset = AM influence information, Data Key = S-NSSAI and DNN and/or (Internal Group Identifier or SUPI or PLMN ID of inbound roamers)).
3a. To create a new request, the AF provides "AM influence information" data to the NEF using the Nnef_AMInfluence_Create service operation (together with the AF identifier and potentially further inputs as specified in clause 5.2.6.23.2), including a target (one UE identified by GPSI, a group of UEs identified by an External Group Identifier, or any UE (for non roaming case), or any inbound roaming UEs identified by their PLMN ID(s)), a list of (DNN, S-NSSAI)(s) and optionally a list of External Application Identifier(s) and requirements related to access and mobility management policies (e.g. service coverage requirements, throughput requirements, AF requested network slice replacement). The AF request contains also an AF Transaction Id and may contain a timer on how long this policy shall last, in which case the system behaviour upon expiration of this timer is as specified in TS 23.503 [20]. If with this request the AF subscribes to access and mobility management related events, the AF indicates also where it desires to receive the corresponding notifications.
The target "any UE" is applicable if an External Application Identifier or list of (DNN, S-NSSAI) is also provided.
The target "any inbound roaming UEs identified by their PLMN ID(s)" is applicable if an External Application Identifier or list of (DNN, S-NSSAI) is also provided.
To update or remove an existing request, the AF invokes an Nnef_AMInfluence_Update or Nnef_AMInfluence_Delete service operation providing the corresponding AF Transaction Id.
The AF requested network slice replacement is only applicable for single UE.
3b. The NEF stores, updates, or removes the policy data of step 3a in the UDR, having translated any External Group Identifier to an Internal Group Identifier and any GPSI to a SUPI.
3c. The UDR informs the NEF about the result of the operation of step 3b.
3d. The NEF informs the AF about the result of the Nnef_AMInfluence operation performed in step 3a.
NOTE 1: Steps 1, 2 and 3 can occur in any order.
4. The UDR notifies the PCF(s) that have a matching subscription (from step 2) about the data stored, updated, or removed in step 3. If matching entries already existed in the UDR when step 2 is performed, this shall be immediately reported to the PCF. The PCF may check that an SM Policy Association is established for the SUPI, DNN, S-NSSAI then subscribe to the SMF to Policy Control Request Trigger to detect the application traffic that triggers the allocation of a service area coverage or an allocation of RFSP index value, then step 6 follows.
5. Steps 2 to 10 in Figure 4.16.14.2.1-1 applies if access and mobility management policies depend on application in use, or steps 2 to 5 in Figure 4.16.14.2.2-1 applies if access and mobility management policies depend on SM Policy Association establishment and termination for a DNN, S-NSSAI combination
6. The PCF for the UE takes a policy decision and then it may initiate an AM Policy Association Modification procedure as described in clause 4.16.2.2. If the AF has subscribed to access and mobility management related events, i.e. request for service area coverage outcome in step 3, then the PCF reports the event (i.e. outcome of the request for service area coverage) to the AF as described in clause 4.16.2.2.
NOTE 2: The PCF for the UE can subscribe to the "start/stop of application traffic detection" events for multiple applications with different application identifiers in the same Npcf_PolicyAuthorization_Subscribe request. When PCF receives the notifications for multiple applications, the PCF for the UE can determine which access and mobility management policy to apply based on local configuration and operator policy. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.10 Application guidance for URSP determination | This clause describes the procedures to allow an AF to provide guidance for URSP determination to 5G system via NEF. The AF may belong to the operator or to an external party. The PCF may be in the Home PLMN, as it is the PCF that determines the URSP for the UE, or in the VPLMN and then the Application guidance for URSP determination is provided to the PCF in the HPLMN via the PCF of the VPLMN. The PCF in the VPLMN translates the Service Parameters values provided by the AF for inbound roamer to values applicable to the HPLMN, e.g. S-NSSAI as described in TS 23.503 [20].
NOTE 1: The operator can negotiate with external party (typically a Corporate represented by an AF) dedicated DNN(s) and/or S-NSSAI(s) for the traffic of UE(s) of this external party. UE(s) of the external party can be identified by a group identifier.
The guidance for URSP determination may be used to provide 5GC with guidance for the URSPs depending on the UE location. This is further described in TS 23.548 [74].
For providing guidance for URSP determination, the procedure defined in clause 4.15.6.7 is performed with the following considerations:
1) Service Description indicates an AF-Service-Identifier.
2) Service Parameters.
Information on the AF guidance for URSP determination which consists of a list of URSP rules that associate an application traffic descriptor with requested features for the candidate PDU sessions the application traffic may use:
- An application traffic descriptor, whose definition corresponds to that of the URSP Traffic Descriptors (as defined for the URSP rule in TS 23.503 [20] Table 6.6.2.1-2). When AF provides application guidance for URSP determination for PIN, the application traffic descriptor shall include PIN ID.
- one or more sets of Route selection parameters, each parameter may correspond to:
- (DNN, S-NSSAI). This may be provided by the AF or determined by the NEF based on the AF-Service-Identifier when it is not provided by the AF and the AF provides only one instance of AF guidance for URSP determination. In the case of AF guidance for URSP determination for PIN, this shall be provided by the AF.
- Requested PDU session type.
- a default Route selection precedence value to be used for the application traffic when Route selection precedence with a corresponding spatial validity condition is not provided.
- Route selection precedence with a corresponding spatial validity condition that indicates where the Route selection parameters apply. This may correspond to a geographical area (e.g. a civic address or shapes).
NOTE 2: The different sets of Route selection parameters indicate different sets of PDU Session information (DNN, S-NSSAI) that can be associated with applications matching the application traffic descriptor. Each set is meant to apply for a specific (set of) spatial validity condition. Each set is associated with a Route selection precedence to cope with the case where multiple spatial validity conditions overlap.
- VPLMN ID(s) that indicates the PLMN(s) where the AF guidance on URSP determination and all its RSD(s), applies.
If the AF provides a geographical area as spatial validity condition, it is up to the NEF to transform this information into 3GPP identifiers (e.g. TAI(s)).
An AF sets the Requested PDU session type if the AF requests to change the PDU session type of the URSP rules.
NEF may, based on local configuration, complement missing service parameters. Additionally, based on operator's local policy, NEF may request UDM for service specific authorization for the service parameters for an individual UE (e.g. to authorize the Corporate or MTC provider represented by the AF and the requested DNN, S-NSSAI for the related UE) before storing the service parameters into the UDR. If the request is targeting a group of UEs, NEF may also request UDM for service specific authorization for the group related data (see table 4.15.6.3b-1), i.e. the DNN, S-NSSAI associated to the group. If the request is targeting any UE (all UEs), NEF authorizes the request based on local policy (e.g. based on AF Id) without requesting for any service specific authorization from UDM. NEF requests UDM for service specific authorization for the service parameters provisioned via the Nudm_ServiceSpecificAuthorisation_Create service operation as defined in clause 4.15.6.7a.
If a group of UEs or any UE is requested, possibility of the PLMN when roaming in other PLMN, each individual UE authorization is performed at a later stage by PCF, the PCF may report a failure of the individual UE authorization to the AF as described in clause 4.15.6.7.2 and in clause 4.15.6.7.3.
NOTE 3: The operator needs to ensure the consistency between the group related data and the UE group members subscription data, i.e. if a group is authorized for a given DNN/S-NSSAI as defined in the group related data, it needs to be ensured that all UE members of the group are provisioned with such DNN/S-NSSAI, since no individual UE check is required to be done by NEF against UDM.
NOTE 4: AF guidance for application traffic is not related with 5G VN group.
3) The Target UE identifier(s) that may be a specific UE, identified by a GPSI, or a group of UE(s), identified by an External-Group-ID, or any UE of the PLMN of the NEF, or the PLMN ID(s) of inbound roamers that the AF request may be associated with.
The information on the AF guidance for URSP determination provided by the AF may be associated to:
a) UEs of the PLMN (of the NEF) when roaming in other PLMNs. In this case, the AF guidance for URSP determination targets to a specific UE, a group of UEs or any UE of the PLMN. In this case, the AF guidance for URSP determination associated to a specific UE, a group of UEs or any UE of the PLMN shall be also associated with the corresponding VPLMN(s) where the AF guidance for URSP determination shall be applied if the UE roams to that VPLMN(s). The list of VPLMN ID(s) is included in the Service Parameters.
b) An inbound roamer from one or more PLMN(s). In this case, the AF targets the AF guidance for URSP determination only with the inbound roamers of corresponding PLMN(s). The PLMN ID is included in the Service Parameters.
NOTE 5: Wildcarding of "PLMN ID of inbound roamers" will be handled by stage 3.
4) Subscription to events.
The AF may subscribe to notifications about the outcome of the UE Policies delivery due to application guidance for URSP determination.
The usage of the AF guidance for application traffic is described in clause 6.6 of TS 23.548 [74]. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.11 Void | |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.12 Parameter Provisioning when the UE is identified via UE addressing information | Handling of Parameter Provisioning requests targeting an individual UE when the UE is identified via UE addressing information is described in clause 4.15.3.2.13. Once this has taken place, the Parameter Provisioning as described in other (sub)clauses of clause 4.15.6 may apply. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.13 Multi-member AF session with required QoS | |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.13.1 General Descriptions | This clause describes the procedure to request QoS and to perform QoS monitoring for the traffic flows for the communication between an AF and a set of UEs, identified by the list of UE address(es). For every UE in the set, this list contains the IP address and the port number that are used by the UE for the communication with the AF.
The NEF receives the request for a Multi-member AF session with required QoS for a set of UEs identified by their addresses. The NEF then maps the request for Multi-member AF session with required QoS to individual requests for AF session with required QoS (i.e. one request for individual AF session with required QoS per UE address) and interacts with each of the UE's serving PCFs on a per AF session basis. The interaction follows the AF session with required QoS procedure as described in clauses 4.15.6.6 and 4.15.6.6a, except that the involvement of the TSCTSF and the provisioning of TSCTSF related information are not supported.
The NEF receives the outcome of the individual requests for AF session with required QoS corresponding to each UE's IP address and consolidates them into a single response before forwarding it to the AF based on a locally configured timer (which could be set to zero).
NOTE 1: The consolidation of the outcome of the individual requests and the locally configured timer allow the optimization of the NEF to AF signalling according to the specific Multi-member AF session with required QoS. Multiple responses could be sent by an NEF (as RAN nodes may responds late or signalling messages may get lost) and the details of the NEF behaviour (e.g. handling of UE addresses for which no response has been received within the locally configured timer) are to be defined by stage 3.
The AF can subscribe to QoS Monitoring (as described in clause 5.45 of TS 23.501 [2]) for the Multi-member AF session with required QoS. If so, QoS monitoring will be activated by the NEF for the whole set of UEs by interacting with each of the UE's serving PCFs on a per AF session basis. The NEF shall always set the NEF ID as the Target of Reporting and include the indication of direct event notification in the request to PCFs regardless of whether AF included the indication of direct event notification or not to ensure that QoS Monitoring reports shall be sent by the UPF directly to the NEF. The NEF forwards the QoS Monitoring reports to the AF together with the respective UE address individually or, optionally, in an aggregated manner based on a locally configured timer.
When the AF subscribes to QoS Monitoring of UL and/or DL data rate (as described in clause 5.45 of TS 23.501 [2]) for the set of UEs, the AF may provide a Consolidated Data Rate threshold that is to be stored in the NEF. The Consolidated Data Rate threshold defines the upper bound of the aggregated data rate across all traffic flows corresponding to the list of UE addresses of the Multi-member AF session with required QoS. The AF may provide in addition a specific list of UE addresses subject to Consolidated Data Rate monitoring (which has to be the subset of the list of UE addresses for the Multi-member AF session), if only a part of the UEs participate in the current communication with the AF and the NEF maintains this list as well. The NEF aggregates the QoS Monitoring reports for data rate for those UEs identified by the specific list of UE addresses subject to Consolidated Data Rate monitoring (if available) or otherwise by the list of UE addresses for the Multi-member AF session with required QoS. The QoS Monitoring reports for data rate will then be sent to the AF by NEF, only if the aggregated data rate exceeds the Consolidated Data Rate threshold.
The following Table 4.15.6.13.1-1 describes the 4 types of requests for the Multi-member AF session with required QoS by the NEF and the corresponding requests to/from PCF using Npcf_PolicyAuthorization service. There may be different PCFs serving the PDU Sessions associated with the UE addresses in the Nnef_AFSessionWithQoS Request.
Table 4.15.6.13.1-1: Mapping of requests for Multi-member AF session with required QoS service to the corresponding Npcf_PolicyAuthorization service operations
Nnef_AFSessionWithQoS Request
Npcf_PolicyAuthorization request
Create
Npcf_PolicyAuthorization_Create request for each UE address received in the Nnef_AFSessionWithQoS Request.
Npcf_PolicyAuthorization_Subscribe to subscribe to QoS Monitoring reports for each UE address targeted for QoS monitoring received in the Nnef_AFSessionWithQoS Request.
Update
Npcf_PolicyAuthorization_Update request to update the QoS and/or QoS monitoring according to the Nnef_AFSessionWithQoS_Update Request.
Npcf_PolicyAuthorization_Create request for each added UE address received in the Nnef_AFSessionWithQoS Request.
Npcf_PolicyAuthorization_Delete request for each removed UE address received in the Nnef_AFSessionWithQoS Request.
Npcf_PolicyAuthorization_Subscribe to subscribe to QoS Monitoring reports for each new UE address targeted for QoS monitoring received in the Nnef_AFSessionWithQoS Request.
More than one of the above operations can be requested at the same time.
Revoke
Npcf_PolicyAuthorization_Delete request for each UE address received in the Nnef_AFSessionWithQoS Request.
Notify
Npcf_PolicyAuthorization_Notify to report the events that NEF subscribed to.
NOTE 2: It is expected that the AF requests QoS and QoS monitoring for a specific traffic flow (used for the communication between a UE address and the AF) with either the procedure for Multi-member AF session with required QoS (described in this clause) or the procedure for AF session with required QoS as described in clause 4.15.6.6 and 4.15.6.6a. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.13.2 Procedures for Creating a Multi-member AF session with required QoS | Figure 4.15.6.13.2-1: Procedures for creating a Multi-member AF session with required QoS
1. The AF sends a request to reserve resources for the traffic flows for the communication between a set of UEs and an AF, using Nnef_AFsessionWithQoS_Create request message (a list of UE addresses, AF Identifier, Flow description information or External Application Identifier, QoS Reference or individual QoS parameters, Alternative Service Requirements (as described in clause 6.1.3.22 of TS 23.503 [20]), QoS parameter(s) to be measured, Reporting frequency, Target of reporting, optional an indication of direct event notification, DNN, S-NSSAI) to the NEF.
The Flow description information, if provided, is common for the list of UEs identified by the list of UE addresses.
- The AF may, instead of a QoS Reference, provide one or more of the following individual QoS parameters: Requested 5GS Delay (optional), Requested Priority (optional), Requested Guaranteed Bitrate, Requested Maximum Bitrate, Maximum Burst Size and Requested Packet Error Rate. The optional Alternative Service Requirements provided by the AF shall either contain QoS References or Requested Alternative QoS Parameter Set(s) in a prioritized order as described in clause 6.1.3.22 of TS 23.503 [20]. The AF may provide QoS parameter(s) to be measured as defined in clause 5.45 of TS 23.501 [2], Reporting frequency, Target of reporting, optional an indication of direct event notification as described in clause 6.1.3.21 of TS 23.503 [20].
The AF may also provide the Consolidated Data Rate threshold and optionally, a list of UE addresses subject to Consolidated Data Rate monitoring. If so, the AF shall also subscribe to QoS Monitoring of UL and/or DL data rate described in clause 5.45 of TS 23.501 [2] .
NOTE 1: When the Consolidated Data Rate threshold is provided, it, by default, applies to the list of UE addresses associated with the Multi-member AF session with required QoS. However, if the specific list of UE addresses subject to Consolidated Data Rate monitoring is also provided together with the Consolidate Data Rate threshold, then such list has to be the subset of the list of UE addresses.
2. The NEF authorizes the AF request that contains a list of UE addresses and may apply policies to control the overall amount of QoS authorized for the AF. If the authorisation is not granted, all steps (except step 8) are skipped and the NEF replies to the AF with a Result value indicating that the authorisation failed. The NEF assigns a Transaction Reference ID to the Nnef_AFsessionWithQoS_Create request. The NEF activates Consolidated Data Rate monitoring only when both the Consolidated Data Rate threshold and a request to do QoS Monitoring of data rate are provided by the AF.
2a. If the NEF recognizes, based on configuration, that the IP address(es) received in the list of UE addresses are different from the IP address(es) assigned by 5GC (i.e. the UE(s) are behind a NAT in UPFs), the NEF performs steps 3 to 6 of the AF specific UE ID retrieval procedure defined in clause 4.15.10 for each UE IP address with port number in order to identify the corresponding IP address (and IP domain, if necessary) that has been assigned by the 5GC. The NEF then uses the respective corresponding IP address (and IP domain, if necessary) in the following steps instead of the UE IP address provided by the AF.
3-4. The NEF finds BSF serving the UE IP address(es) using NRF and then for each UE IP address, the NEF uses Nbsf_Management_Discovery service operation, providing the UE IP address, to discover the responsible PCF for each of the PDU Sessions.
Steps 5-7 apply for each UE address in the list of UE addresses.
5. The NEF provides the UE address and the received parameters in step 1 to the PCF in the Npcf_PolicyAuthorization_Create request. NEF shall include the Target of reporting and indication of direct event notification to PCF as described in clause 4.15.6.13.1.
6. Step 4 in Figure 4.15.6.6-1 applies. The PCF generates authorized QoS Monitoring policy according to the QoS Monitoring information if received from the NEF in step 5 and provides PCC rules with the policy to the SMF as described in clause 6.1.3.21 of TS 23.503 [20]. The SMF configures the UPF to perform QoS Monitoring as described in clause 5.8.2.18 of TS 23.501 [2].
7. The PCF sends the Npcf_PolicyAuthorization_Create response message to the NEF.
8. The NEF aggregates the authorization responses from the PCFs and sends a Nnef_AFsessionWithQoS_Create response message (Transaction Reference ID, Result for list of UE addresses) with the aggregated authorization responses to the AF. Result for list of UE addresses includes whether the authorization was successful or has failed for every UE address in the list. The NEF stores the list of UE addresses for which the authorization was successful together with the Transaction Reference ID, the QoS and the QoS monitoring information.
Steps 9-10 apply for each UE address in the list of UE addresses.
9. Step 6 in Figure 4.15.6.6-1 applies.
10. Step 7 in Figure 4.15.6.6-1 applies.
11. The NEF aggregates the notifications from the PCFs and sends a Nnef_AFsessionWithQoS_Notify message (Transaction Reference ID, Result for list of UE addresses) with the aggregated resource allocation status events to the AF. Result for list of UE addresses includes, for every UE address in the list, the information whether resources are allocated, resources are not allocated or resources are allocated while the currently fulfilled QoS matches an Alternative Service Requirement. The NEF updates the locally stored list of UE addresses by removing any UEs for which resources could not be allocated.
NOTE 2: For those UE address(es) that did not get any resources, the AF may request resource reservation again, by adding them to the list of UE address(es) as described in clause 4.15.6.13.3.
12. As direct event notification is requested based on the parameters received in step 5, the QoS Monitoring events are reported by the UPF(s) to the NEF using Nupf_EventExposure service as described in clause 5.2.26.2.
13. When the NEF receives QoS Monitoring events, the NEF sends Nnef_AFsessionWithQoS_Notify message with the individual or aggregated QoS Monitoring events to the AF as described for the QoS Monitoring and the Consolidated Data Rate monitoring in clause 4.15.6.13.1. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.13.3 Procedure for updating a Multi-member AF session with required QoS | Figure 4.15.6.13.3-1: Procedure for updating a Multi-member AF session with required QoS
1. The AF which controls the Multi-member AF Session with required QoS invokes the Nnef_AFSessionWithQoS_Update Request to update the list of UE addresses and/or to update the QoS and/or to update the QoS monitoring and/or to update the Consolidated Data Rate monitoring.
The Nnef_AFSessionWithQoS_Update request includes the Transaction Reference ID and one or more of the parameters that are listed in step 1 of the procedure for creating a Multi-member AF session with required QoS in clause 4.15.6.13.2 which the AF needs to update (or provide for the first time).
NOTE 1: For example, the AF can subscribe to QoS monitoring or Consolidated Data Rate monitoring for the Multi-member AF session with required QoS if this has not been done during the procedure for creating a Multi-member AF session with required QoS, as described in clause 4.15.6.13.2.
NOTE 2: If AF needs to terminate the Consolidated Data Rate monitoring for the Multi-member AF session with required QoS, the AF does not include the Consolidate Data Rate threshold in the AF request.
2. The NEF authorizes the AF request and may apply policies to control the overall amount of QoS authorized for the AF. If the authorisation is not granted, all following steps are skipped and the NEF replies to the AF with a Result value indicating that the authorisation failed. The NEF performs Consolidated Data Rate monitoring only when both the Consolidated Data Rate threshold and a request to do QoS Monitoring of data rate are provided by the AF.
3-5. When the AF provides an Nnef_AFSessionWithQoS_Update Request in order to add/update/remove the Consolidated Data Rate threshold or the list of UE addresses subject to Consolidated Data Rate monitoring, the NEF updates its local context and does not interact with the PCF(s) (unless required for reasons described in the following).
When the AF provides an Nnef_AFSessionWithQoS_Update Request in order to update the list of UE addresses, to update the QoS and/or to update the QoS monitoring, the NEF refers to the locally stored information (i.e. the list of UE addresses, the QoS and the QoS monitoring information) and determines which new UE address is to be added to the list, which of the existing UE address is to be removed from the list and/or for which of the existing UE address(es) the QoS or the QoS monitoring (or both) is to be updated. Then, the NEF continues by invoking one of the following Npcf_PolicyAuthorization procedures for every affected UE address:
a) If the NEF determines that a new UE is to be added to the list, the NEF performs steps 2a to 7 of clause 4.15.6.13.2 for the corresponding UE. The NEF uses the latest information on QoS and QoS monitoring for the interaction with the PCF. The NEF adds the address of the new UE to the locally stored list of UE addresses if the authorization was successful.
b) If the NEF determines that an existing UE is to be removed from the list, the NEF initiates the Npcf_PolicyAuthorization_Delete as described in clause 5.2.5.3.4 excluding TSCTSF related info towards the PCF for the corresponding UE. The NEF removes the UE address from the locally stored list of UE addresses.
c) If the NEF determines that an update of the QoS or the QoS monitoring or both for existing UE addresses is necessary, the NEF initiates the Npcf_PolicyAuthorization_Update to the respective UE's serving PCF(s) on a per AF session basis and step 4 in Figure 4.15.6.6a-1 applies. The NEF removes any UE addresses for which the authorization of the update request has failed from the list of UE addresses. The NEF stores any change to the QoS or the QoS monitoring information.
6. When an interaction with PCF(s) has occurred during step 5, the NEF aggregates the authorization responses from the PCF(s) and sends the Nnef_AFSessionWithQoS Update response (Transaction Reference ID, Result for list of UE addresses) with the aggregated authorization results to the AF. Result for list of UE addresses includes whether the request is granted or not for every UE address in the list.
When no interaction with PCF(s) has occurred during step 4 and 5, the NEF sends the Nnef_AFSessionWithQoS Update response (Transaction Reference ID, Result) with the result of the Consolidated Data Rate monitoring related change to the AF.
7. For every UE address that has been added to the locally stored list of UE addresses, the NEF shall send a Npcf_PolicyAuthorization_Subscribe message to the respective PCF(s) to subscribe to notifications of Resource allocation status and may subscribe to other events described in clause 6.1.3.18 of TS 23.503 [20]. If an update of event subscription is requested by the AF, the NEF updates the event subscription with the respective PCF(s) for every UE address in the locally stored list of UE addresses.
8. Step 7 in Figure 4.15.6.6-1 applies, at least for those UE addresses for which the establishment or update of transmission resources was requested by the PCF(s).
9. When the establishment or update of transmission resources occurs, the NEF receives Npcf_PolicyAuthorization_Notify messages from the UE's serving PCF(s) about the Resource allocation status. The NEF aggregates the notifications from the respective UEs' serving PCFs before notifying the AF with a Nnef_AFSessionWithQoS_Notify message (Transaction Reference ID, Result for list of UE addresses). Result for list of UE addresses includes, for every UE address in the list, the information whether resources are allocated, resources are not allocated or resources are allocated while the currently fulfilled QoS matches an Alternative Service Requirement. The NEF updates the locally stored list of UE addresses by removing any UEs for which resources could not be allocated.
NOTE 3: For those UE address(es) that did not get any resources, the AF may request resource reservation again, by adding them to the list of UE address(es) as described in clause 4.15.6.13.3.
10. As direct event notification is requested, the UPF(s) provide the QoS Monitoring events to the NEF using Nupf_EventExposure service as described in clause 5.2.26.2.
11. When the NEF receives QoS Monitoring events, the NEF sends Nnef_AFsessionWithQoS_Notify message with the individual or aggregated QoS Monitoring events to the AF as described for the QoS Monitoring and the Consolidated Data Rate monitoring in clause 4.15.6.13.1. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.13.4 Procedure for Revoking a Multi-member AF session with required QoS | Figure 4.15.6.13.4-1: Procedure for revoking a Multi-member AF session with required QoS
1. The AF sends a request to revoke the allocated resources for the traffic flows for the communication between a set of UEs and an AF, using Nnef_AFsessionWithQoS_Revoke request message (Transaction Reference ID).
2. The NEF authorizes the AF request.
Steps 3-5 apply for each UE address in the list of UE addresses associated with the Transaction Reference ID:
3. The NEF sends the Npcf_PolicyAuthorization_Delete request as described in clause 5.2.5.3.4 to the PCF.
4. The PCF proceeds with the SM Policy Association Modifications procedure as defined in clause 4.16.5.2. If the NEF has subscribed to notifications (e.g. on resource allocation status, QoS Monitoring of UL and/or DL data rate) for the UE address in the Multi-member AF session, the subscription is also removed.
5. The PCF sends the Npcf_PolicyAuthorization_Delete response message to the NEF.
6. The NEF sends the Nnef_AFsessionWithQoS_Revoke response message (Transaction Reference ID) to the AF. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.14 Procedures for AF requested QoS for a UE or group of UEs not identified by a UE address | Figure 4.15.6.14-1: Procedure for AF requested QoS for a UE or group of UEs not identified by a UE address
0. When a new PDU Session is established, based on local configuration associated with the DNN/S-NSSAI, the PCF determines if the PDU Session needs involvement of TSCTSF. If the TSCTSF is used the PCF invokes Npcf_PolicyAuthorization_Notify service operation to the TSCTSF discovered and selected as described in clause 6.3.24 of TS 23.501 [2]. The Npcf_PolicyAuthorization_Notify service operation includes the UE address of the PDU Session and DNN/S-NSSAI. If the TSCTSF is not used, the PCF subscribes to notifications for Application Data from UDR.
NOTE: In the case of private IPv4 address being used for the UE, the DNN and S-NSSAI are required for session binding in the PCF.
The PCF registers to BSF as described in TS 23.503 [20]. When the TSCTSF is used, the TSCTSF invokes a Npcf_PolicyAuthorization_Create request message to the PCF and stores the DNN, S-NSSAI and IP address as received from PCF and SUPI as received from BSF and associates them with the AF-session.
1. The AF sends a request to reserve resources using Nnef_AF_Request_QoS_Create request message (GPSI or External Group ID, AF Identifier, Flow description(s) or External Application Identifier, QoS reference or individual QoS parameters, Alternative Service Requirements (as described in clause 6.1.3.22 of TS 23.503 [20]), DNN, S-NSSAI) to the NEF. Optionally, a period of time or a traffic volume for the requested QoS can be included in the AF request. The AF may, instead of a QoS Reference, provide the individual QoS parameters. Regardless, whether the AF request is formulated using a QoS Reference or Individual QoS paramaters, the AF may also provide one or more of the parameters that describe the traffic characteristics as described in clause 6.1.3.28 of TS 23.503 [20].
2. This step is the same as step 2 in clause 4.15.6.6.
3. This step is the same as steps 2-4 in clause 4.15.6.7a.
The NEF determines whether to invoke the TSCTSF or not, as described in step 2 in clause 4.15.6.6. If the NEF determines to invoke TSCTSF, steps 4-9 are executed and steps 10-12 are skipped. Otherwise steps 4-9 are skipped and steps 10-12 are executed. The procedure then continues in step 13.
4. This step is the same as step 3a in clause 4.15.6.6 with the difference that Internal Group ID or SUPI is provided instead of UE address.
5. If the group members are identified by GPSI or External/Internal Group ID, the TSCTSF uses the Nudm_SDM_Get request to retrieve the subscription information (SUPI(s)) from the UDM using each GPSI or the External/Internal Group Identifier received in step 4 The TSCTSF also determines which of these group members have active PDU Sessions matching the DNN/S-NSSAI and determines the relevant UE address. The TSCTSF manages the AF request QoS information targeting for a group as defined in TS 23.501 [2].
6. For each PDU Session, the TSCTSF invokes Npcf_PolicyAuthorization service. This step is the same as step 3b in clause 4.15.6.6.
7. The PCF replies to the TSCTSF. This step is the same as step 4a in clause 4.15.6.6.
8. The TSCTSF replies to the NEF. This step is the same as step 4b in clause 4.15.6.6.
9. This step is the same as step 6a in clause 4.15.6.6 with the difference that it is executed for all PDU Sessions identified in step 6 above.
10. If the NEF determines to not invoke the TSCTSF, the NEF uses the Nudr_DM service to store the information related to the Internal Group ID or SUPI in UDR. The information is stored as Application Data in UDR. If the AF requested for notifications of Resource allocation status or other events, the NEF includes the information required for reporting the event, including the Notification Target Address pointing to the NEF or AF and the Notification Correlation ID containing the AF Transaction Internal ID. This step is the same as step 3 in clause 4.15.6.7.2 except the Data Subset of "Application Data" is set to "AF request for QoS information".
11. The UDR notifies the PCF(s) that have subscribed.
12. The PCF(s) identifies the active PDU Sessions associated with the data received from UDR. The PCF(s) manages the AF request QoS information targeting for a group as defined in TS 23.503 [20].
13. The NEF replies to the AF. This step is the same as step 8 in clause 4.15.6.6.
14. When an event condition is met, e.g. that the establishment of the transmission resources corresponding to the QoS update succeeded or failed, the PCF sends a notification to TSCTSF or NEF as applicable. This step is the same as steps 7-8 in clause 4.15.6.6. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.6.15 Provisioning of Non-3GPP Device Identifier Information | This clause describes the procedures to allow an AF to provision QoS information for the non-3GPP device(s) (as defined in clause 5.52 of TS 23.501 [2]) that require differentiated QoS treatment for a UE subscription to the 5G system via NEF. The AF may belong to the operator or to an external party.
To provision QoS information for the non-3GPP device(s) that require differentiated QoS treatment, the steps 1 to 4 of procedure defined in clause 4.15.6.7.2 is performed with the following considerations:
1) Service Description. Contains an AF-Service-Identifier indicating that the request is for providing Non-3GPP Device Identifier Information.
2) Service Parameters. Contains the Non-3GPP Device Identifier Information which has the following parameters:
- Non-3GPP Device Identifier, a generic string, which uniquely identifies a non-3GPP device behind a specific UE subscription.
- QoS reference or individual QoS parameters as described in clause 6.1.3.22 of TS 23.503 [20].
- Optionally, DNN and S-NSSAI. This may be provided by the AF or may be determined by the NEF based on the AF-Service-Identifier if not provided by the AF.
- Optionally, Flow description information as specified in clause 6.1.3.6 of TS 23.503 [20]
3) The Target UE identifier(s). A specific UE identified by e.g. GPSI or SUPI.
4) The parameters and operation for UE policy delivery is not needed.
The NEF sets the value of Data Subset Identifier to "Non-3GPP Device Identifier Information" in Nudr_DM_Create/Update/Delete service operations when storing/updating/deleting this data. NEF determines to use this data subset based on AF-Service-Identifier. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.7 Network status reporting | This clause contains the detailed description and the procedures for the network status reporting capability.
An AF may request for being notified about the network status, in a specific geographical area or for a specific UE.
The following methods are supported:
- The AF requests to be informed, one-time, about the network status. This procedure is referred to as one-time network status request;
- The AF requests to be informed, continuously, about the network status. This procedure is referred to as continuous network status request;
The procedure as described in clause 6.1.1.2 or clause 6.1.2.2 of TS 23.288 [50] is used by an AF to retrieve Network Status Result (NSR) from the network for a specific geographical area or for a specific UE.
After receiving the request for network status notification from the AF, the NEF retrieves user data congestion analytics information from NWDAF, as defined in TS 23.288 [50].
Based on the user data congestion analytics information the NEF receives from the NWDAF, the NEF derives and reports the network status for the geographical area or for the UE as Network Status Result (NSR) to the AF. When reporting to the AF, the NSR shall not include any 3GPP location information.
NOTE 1: Either exact values for congestion status, as reported by NWDAF to NEF or abstracted values e.g. (High, Medium, Low) can be reported by the NEF to the AF. The calculation and the reporting of the NSR to the AF depends on operator configuration (e.g. SLAs, usage etc.).
When an AF requests one-time Network Status from the NEF, the NEF can optionally provide a time interval at which the AF is allowed to re-issue the same request for network status.
NOTE 2: The time interval provided by NEF can be ignored by the AF if the subsequent request on network status is considerably different with regards to the geographical area or the UE. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.8 Event exposure controlled by a DCCF | A DCCF can coordinate the subscriptions and notifications to event exposure in Network Functions. This is further described in TS 23.288 [50]. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.9 Time Synchronization exposure | |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.9.1 General | Time synchronization exposure allows an AF to configure time synchronization in 5GS. For (g)PTP operation, the Time synchronization service allows an AF to subscribe to the UE and 5GC capabilities and availability for time synchronization service (as described in clause 4.15.9.2), to configure the (g)PTP instance in 5GS as described in clause 4.15.9.3 and monitor service status as described in clause 4.15.9.5. For 5G access stratum based time distribution, the AF can influence the 5G access stratum time distribution as described in clause 4.15.9.4 and monitor service status as described in clause 4.15.9.5. The time synchronization exposure is provided by NEF that uses the service provided by TSCTSF. The AF that is part of operator's trust domain may invoke the services directly with TSCTSF and TSCTSF responds/notifies directly to the AF, accordingly.
NOTE: The AF can use either the procedure for configuring the (g)PTP instance in 5GS as described in clause 4.15.9.3 or the procedure for controlling the 5G access stratum time distribution as described in clause 4.15.9.4 for a particular UE. The procedures are not intended to be used in conjunction with each other by the AF. However, the (g)PTP instance activation, modification and deactivation can influence the 5G AS time distribution for the UEs that are part of the impacted PTP instance. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.9.2 Exposure of UE availability for Time Synchronization service | The procedure is used by the AF to subscribe to notifications and to explicitly cancel a previous subscription for UE availability for time synchronization service. Cancelling is done by sending Nnef_TimeSynchronization_CapsUnsubscribe request identifying the subscription to cancel with Subscription Correlation ID.
Figure 4.15.9.2-1: Procedure for exposing 5GS and/or UE availability and capabilities for Time Synchronization services
1. Upon PDU Session establishment, the PCF determines if the PDU Session is potentially impacted by time synchronization service (based on local configuration or 5GS Bridge/Router information event from SMF as described in SM Policy Association Establishment procedure in clause 4.16.4). In this case the PCF invokes Npcf_PolicyAuthorization_Notify service operation to the TSCTSF discovered and selected as described in clause 6.3.24 of TS 23.501 [2]. The Npcf_PolicyAuthorization_Notify service operation includes the UE address of the PDU Session and DNN/S-NSSAI.
NOTE: In the case of private IPv4 address being used for the UE, the DNN and S-NSSAI are required for session binding in the PCF.
The PCF registers to BSF as described in TS 23.503 [20]. TSCTSF invokes a Npcf_PolicyAuthorization_Create request message to the PCF and stores the DNN, S-NSSAI and IP address as received from PCF and SUPI as received from BSF and associates them with the AF-session.
If PMIC/UMIC information from the DS-TT or NW-TT is available at the PCF, the PCF reports it to the TSCTSF invoking Npcf_PolicyAuthorization_Notify.
2. The AF subscribes to the UE availability for time synchronization service and provides the associated Notification Target Address of the AF by sending Nnef_TimeSynchronization_CapsSubscribe request.
Report Type defines the type of reporting requested (e.g. one-time reporting, periodic reporting or event based reporting).
The request may include DNN and slicing information (S-NSSAI) and shall include an AF-Service-Identifier. If the DNN and S-NSSAI are omitted in the request, the NEF uses the AF-Service-Identifier to determine the target DNN and slicing information (S-NSSAI).
The Event Filter may include a list of UE identities (GPSIs) or Groups of UEs identified by an External Group Identifier that further define the subset of the target UEs. If the request does not include UE identities nor External Group Identifier, the request is targeted to any UE with a PDU Session using the DNN and S-NSSAI. The NEF forwards the GPSIs or the External Group Identifier to the TSCTSF by including them/it inside the Ntsctsf_TimeSynchronization_CapsSubscribe request.
Additionally, the Event Filter may include one or more of the requested PTP instance type, requested transport protocol for PTP, or requested PTP Profile as described in Table 5.2.6.25.6-1.
When the NEF processes the AF request the AF-Service-Identifier may be used to authorize the AF request.
Depending on the AF-Service-Identifier and/or DNN/S-NSSAI, the NEF may reject the request if the list of UE identities or External Group Identifier is not included in the request.
To unsubscribe to the UE availability for time synchronization for a list of UE(s), the AF invokes Nnef_TimeSynchronization_CapsUnsubscribe service operation and provides the Subscription Correlation ID.
3. (In the case of Ntsctsf_TimeSynchronization_CapsSubscribe): The NEF discovers the TSCTSF as described in clause 6.3.24 of TS 23.501 [2]. The NEF invokes the Ntsctsf_TimeSynchronization_CapsSubscribe request service operation to the selected TSCTSF.
(In the case of Ntsctsf_TimeSynchronization_CapsUnsubscribe): The NEF uses the Subscription Correlation ID to determine the TSCTSF and interacts with the TSCTSF by triggering a Ntsctsf_TimeSynchronization_CapsUnsubscribe request message.
The AF that is part of operator's trust domain may invoke the services directly with TSCTSF.
4. If the Event Filter includes GPSI(s), an External Group Identifier or an Internal Group Identifier, the TSCTSF uses the Nudm_SDM_Get request to retrieve the subscription information (SUPI(s)) from the UDM using each GPSI or the External Group Identifier as received from the NEF or an Internal Group Identifier as provided directly by the AF (in the case when the AF is within the operator's domain).
The TSCTSF requests the Time Synchronization Subscription data from the UDM. The TSCTSF may also use stored Time Synchronization Subscription data which it retrieved from the UDM when the UE established PDU session, see clause 4.28.3.1.
5. The UDM provides the Nudm_SDM_Get response containing SUPI that are mapped from each received GPSI or a list of SUPIs mapped from the External/Internal Group Identifier and identify UEs targeted by the AF request.
6. (in the case of Ntsctsf_TimeSynchronization_CapsSubscribe): The TSCTSF uses the parameters received in step 3 and step 5 (i.e. DNN, S-NSSAI and the list of SUPIs if present) to find matching AF-session(s).
If the Time Synchronization Subscription data is available, the subscription data returned by the UDM includes the AF request authorization that indicates whether the AF is allowed to request (g)PTP-based time distribution for DNN/S-NSSAI. If the subscription data indicates that the AF is not allowed to request (g)PTP-based time synchronization, the AF-session is excluded from the list of matching AF-sessions.
For any such matching AF-session, the TSCTSF interacts with the PCF by triggering a Npcf_PolicyAuthorization_Update request message.
(in the case of Ntsctsf_TimeSynchronization_CapsUnsubscribe): The TSCTSF uses the Subscription Correlation ID to determine the AF sessions and interacts with the PCF(s) by triggering a Npcf_PolicyAuthorization_Delete request message. Steps 10-15 are skipped.
7. TSCTSF acknowledges the execution of Ntsctsf_TimeSynchronization_CapsSubscribe to the requester that initiated the request. The acknowledgement contains a Subscription Correlation ID that the requester can use to cancel or modify the subscription.
8. NEF acknowledges the execution of Nnef_TimeSynchronization_CapsSubscribe to the requester that initiated the request. The acknowledgement contains a Subscription Correlation ID that the AF can use to cancel or modify the subscription.
9. As part of Npcf_PolicyAuthorization_Update request, the TSCTSF uses the procedures as described in clause K.2.1 of TS 23.501 [2] to determine the (g)PTP capabilities from the DS-TT. If the TSCTSF has not determined the (g)PTP capabilities from the NW-TT, the TSCTSF determines the capabilities using the procedures as described in clause K.2.1 of TS 23.501 [2].
The TSCTSF composes the time synchronization capabilities for the DS-TT/UE(s) connected to the NW-TT based on the capability information received from the DS-TT(s) and NW-TT. If the Ntsctsf_TimeSynchronization_CapsSubscribe request include an Event Filter with one or more of the requested PTP instance type, requested transport protocol for PTP, or requested PTP Profile, the TSCTSF considers only the DS-TT(s) and NW-TT(s) with these capabilities as part of the time synchronization capability set that is reported to the NEF (or AF).
The TSCTSF maintains association between the user-plane Node ID, the time synchronization capabilities, the reference to the capabilities (as identified by the Subscription Correlation ID), the Event Filter (if available), the NEF or AF Notification Target Address and list of the AF sessions with PCFs with this user-plane Node ID. If the Ntsctsf_TimeSynchronization_CapsSubscribe request includes one or more Event Filter(s), the TSCTSF considers only the matching UE identities and the DS-TT(s) and NW-TT(s) with the matching capabilities to be included in the associated AF sessions.
10. The TSCTSF sends Ntsctsf_TimeSynchronization_CapsNotify (as described in clause 5.2.27.2.8) to the NEF. The message includes the time synchronization capabilities as composed in step 9. The message contains one or more user-plane Node ID(s) and a list of UE identities associated to each user-plane Node ID and time synchronization capabilities for each set of DS-TTs connected to given user-plane Node ID, as described in Table 5.2.6.25.8-1. The user-plane Node ID identifies the NW-TT to where the UE/DS-TT(s) are connected to.
11. The NEF sends Nnef_TimeSynchronization_CapsNotify with Time Synchronization capability event (as described in Table 5.2.6.25.8-1) to the AF.
12-13. Upon PDU Session Establishment as defined clause 4.3.2.2.1, steps 1, 9, 10 and 11 are repeated for the new PDU Session.
14. If necessary, e.g. upon PDU Session establishment or release, the TSCTSF may update the time synchronization capabilities for the DS-TT/UE(s) connected to the NW-TT(s). The TSCTSF sends Ntsctsf_TimeSynchronization_CapsNotify with Time Synchronization capability event (as described in Table 5.2.6.25.8-1) containing the updated capabilities to the NEF.
15. The NEF sends Nnef_TimeSynchronization_CapsNotify containing the updated capabilities to the AF. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.9.3 Time Synchronization activation, modification and deactivation | |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.9.3.1 General | This procedure can be used by the AF to activate, modify or deactivate the (g)PTP instances in 5GS.
The AF may activate the time synchronization service using the Nnef_TimeSynchronization_ConfigCreate service operation. The service operation creates a time synchronization configuration based on the service parameters as indicated in the create request. The AF may update the time synchronization configuration using the Nnef_TimeSynchronization_ConfigUpdate service operation. The AF may deactivate the time synchronization service using the Nnef_TimeSynchronization_ConfigDelete service operation, which deletes the corresponding time synchronization service configuration. The AF may subscribe to time synchronization status report by providing clock quality acceptance criteria via Nnef_TimeSynchronization_ConfigCreate service operation. The AF may receive time synchronization service status update via Nnef_TimeSynchronization_UpdateNotify service operation. 5GS may provide a time synchronization status report to the AF in case of a PTP port is activated or deactivated due to a detected failure, degradation, or improvement of the service.
The Nnef_TimeSynchronization_ConfigCreate and Nnef_TimeSynchronization_ConfigUpdate request may contain the parameters as described in Table 4.15.9.3-1.
Table 4.15.9.3-1: Description of Time Synchronization service parameters
Time Synchronization Parameter
Description
PTP instance type
Identifies the requested PTP instance type as described in clause 5.27.1.4 of TS 23.501 [2].
Transport protocol
Identifies the requested transport protocol for PTP instance as described in clause 5.27.1.4 of TS 23.501 [2]. This is applicable for IEEE Std 1588 [76] Boundary Clock and Transparent Clock operation.
PTP Profile
Identifies the PTP profile for the PTP instance as requested by AF.
Grandmaster enabled
Indicates whether the AF requests the PTP instance in 5GS to be able to act as a grandmaster for PTP or gPTP (depending on the requested PTP instance type).
This is applicable for IEEE Std 1588 [76] Boundary Clock or IEEE Std 802.1AS [75] operation.
[optional]
Grandmaster priority
Indicates a priority used as defaultDS.priority1 when generating Announce message when 5GS acts as (g)PTP GM. Applicable only if the Grandmaster enabled = TRUE. If omitted, the default value as described in the PTP Profile is used.
[optional]
Time Domain
(g)PTP domain of the PTP instance as defined in IEEE Std 1588 [76].
Temporal Validity Condition
Indicates start-time and stop-time attributes that describe the time period when the time synchronization service for a PTP instance is active.
[optional]
Spatial Validity Condition
Indicates a geographical area (e.g. a civic address or shapes) or a TA list in which time synchronization service is enabled (NOTE 1).
[optional]
Time synchronization error budget
Indicates the time synchronization budget for the time synchronization service (as described in clause 5.27.1.9 of TS 23.501 [2]).
[optional]
Clock quality detail level
For (g)PTP services, its value, if provided, shall be set to "acceptable/not acceptable indication" (NOTE 2).
[optional]
Clock quality acceptance criteria
It indicates the acceptable criteria for the UE. It is defined based on the attributes
specified in Table 5.27.1.12-1 of TS 23.501 [2]. The parameter shall be included if the "clock quality detail level" is present.
[conditional]
For each PTP port in the PTP instance
Either UE identity (for a DS-TT port), or "N6 interface" indication
Identifies the UE/DS-TT which the parameters below apply. "N6 interface" indicates that the parameters below apply to the N6 interface.
If the "PTP port" needs to be identified, this field refers to the UE identity (GPSI or SUPI).
If the N6 termination needs to be identified, then this field indicates "N6 interface" flag, instead of SUPI or GPSI.
PTP enabled
TRUE/FALSE. This is used to set the portDS.portEnable. If omitted, the default value as described in the PTP Profile is used.
[optional]
Log Sync Interval
Specifies the mean time interval between successive Sync messages. This is applicable for IEEE Std 1588 [76] Boundary Clock or IEEE Std 802.1AS [75] operation. If omitted, the default value as described in the PTP Profile is used.
[optional]
Use management settable Log Sync Interval
TRUE/FALSE. This is applicable if the PTP Profile is I IEEE Std 802.1AS [75].
When set to FALSE, the Log Sync Interval is used to set the initialLogSyncInterval as described in IEEE Std 802.1AS [75]. When set to TRUE, the Log Sync Interval is used to set the mgtSettableLogSyncInterval as described in IEEE Std 802.1AS [75].
If omitted, the default value as described in the IEEE Std 802.1AS [75] is used.
[optional]
Log Announce Interval
Specifies the mean time interval between successive Announce messages. This is applicable for IEEE Std 1588 [76] Boundary Clock or IEEE Std 802.1AS [75] operation. If omitted, the default value as described in the PTP Profile is used.
[optional]
Use management settable Log Announce Interval
TRUE/FALSE. This is applicable if the PTP Profile is IEEE Std 802.1AS [75].
When set to FALSE, the Log Announce Interval is used to set the initialLogAnnounceInterval as described in IEEE 802.1AS. When set to TRUE, the Log Announce Interval is used to set the mgtSettableLogAnnounceInterval as described in IEEE Std 802.1AS [75].
If omitted, the default value as described in the IEEE Std 802.1AS [75] is used.
[optional]
NOTE 1: A geographical area requested by an AF includes at least one tracking area (TA), i.e. the granularity is restricted to a TA level in this release of the specifications.
NOTE 2: UE/DS-TT retrieves detailed information about (g)PTP services status from Announce messages, i.e. setting Clock Quality Detail Level to "Acceptable/Not Acceptable" indication can be used to specify Clock Quality Acceptance Criteria for Timing Synchronization Status (TSS) reporting towards the AF.
The AF may use Nnef_TimeSynchronization_CapsSubscribe service operation as described in clause 4.15.9.2 to learn the UE capabilities for time synchronization service. The Nnef_TimeSynchronization_CapsNotify service operation indicates the list of UE identities, User-plane Node ID and the Subscription Correlation ID. The AF can use the Subscription Correlation ID and the user-plane node ID received in the Nnef_TimeSynchronization_CapsNotify service operation as a target of the Nnef_TimeSynchronization_ConfigCreate request. The NEF uses the Subscription Correlation ID and user-plane node ID to determine the list of UEs and list of AF-sessions to which the Nnef_TimeSynchronization_ConfigCreate service operation is targeted to. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.9.3.2 Time synchronization service activation | Figure 4.15.9.3.2-1: Time synchronization service activation
1. The AF creates a time synchronization service configuration for a PTP instance by invoking Nnef_TimeSynchronization_ConfigCreate service operation. The request includes the parameters as described in Table 4.15.9.3-1. The request contains a Subscription Correlation ID and user-plane node ID as a reference to the target of the UEs and AF-sessions.
The create request creates also a subscription for the changes in the time synchronization service configuration. The AF may subscribe to receiving network time synchronization status report(s) as specified in clause 4.15.9.5.1.
2. The NEF authorizes the request. After successful authorization, the NEF invokes the Ntsctsf_TimeSynchronization_ConfigCreate service operation with the corresponding TSCTSF, with the parameters as received from the AF.
If the request includes a spatial validity condition and if the AF uses a geographical area as a spatial validity condition, the NEF transforms this information into 3GPP identifiers (e.g. TAI(s)) based on pre-configuration.
The AF that is part of operator's trust domain may invoke the services directly with TSCTSF.
If the request includes a spatial validity condition and if the AF is within the operator's domain, the spatial validity condition shall comprise of a list of TA(s).
NOTE 1: It is assumed that AFs within the operator's domain is aware of TAs that can be used to formulate a spatial validity condition for Time Synchronization Coverage Area (see clause 5.27.1.10 of TS 23.501 [2]).
3. TSCTSF checks whether the AF requested parameters comply with the stored Time Synchronization Subscription data as defined in clause 5.27.1.11 of TS 23.501 [2], for that, the TSCTSF retrieves the Time Synchronization Subscription data from the UDM (as defined in clause 4.15.9.2). The TSCTSF determines the Time Synchronization Coverage Area and responds with the Ntsctsf_TimeSynchronization_ConfigCreate response as specified in clause 5.27.1.11 of TS 23.501 [2]. The Ntsctsf_TimeSynchronization_ConfigCreate response includes a PTP instance reference.
4. The NEF responds with the Nnef_TimeSynchronization_ConfigCreate response, including a reference to the time synchronization service configuration (PTP instance reference).
5-6. The TSCTSF uses the Subscription Correlation ID and user-plane node ID in Ntsctsf_TimeSynchronization_ConfigCreate to determine the target UEs and corresponding AF-sessions. The TSCTSF uses the parameters (e.g. requested PTP instance type, transport protocol and PTP profile) in the Ntsctsf_TimeSynchronization_ConfigCreate request to determine suitable DS-TT(s) and corresponding AF-sessions among all AF-sessions that are associated with the Subscription Correlation ID and user-plane node ID in the request.
The TSCTSF maintains association between list of suitable AF-sessions, corresponding time synchronization configuration, the PTP instance reference in 5GS, PTP instance references in each involved DS-TT and NW-TT and Subscription Correlation ID and user-plane node ID as given in step 1.
NOTE 2: The AF-sessions that are not associated with a time synchronization configuration, are available to be selected as suitable AF-sessions in another Ntsctsf_TimeSynchronization_ConfigCreate request.
The TSCTSF uses the procedures described in clause K.2.2 of TS 23.501 [2] to configure and initialize the PTP instance in the DS-TT(s) and NW-TT. The TSCTSF constructs a PMIC to each DS-TT/UE to activate the time synchronization service in DS-TT in respect to the service parameters in the request in step 2. The TSCTSF constructs PMIC(s) and UMIC to NW-TT to activate the time synchronization service in NW-TT in respect to the service parameters in the request in step 2.
Upon reception of responses from each DS-TT and NW-TT, the TSCTSF determines the state of the time synchronization configuration.
The TSCTSF constructs a PMIC to each DS-TT/UE to subscribe for the port management information changes in the DS-TT. The TSCTSF constructs PMIC(s) and UMIC to NW-TT to subscribe for the port management and user-plane management information changes in NW-TT. The TSCTSF retrieves the PMIC(s) and UMIC via means of Npcf_PolicyAuthorization service operations.
The create request creates also a subscription for notifications for the changes in the time synchronization service configuration. If the AF provided clock quality acceptance criteria in step 1, the TSCTSF subscribes for notifications for changes in the NG-RAN and UPF/NW-TT timing synchronization status, as described in clause 4.15.9.5.1:
- To determine the impacted UEs due to a timing synchronization status update reported by the NG-RAN, the TSCTSF follows the operation described in clause 5.27.1.12 of TS 23.501 [2].
- To determine the impacted UEs due to a timing synchronization status update reported by the UPF/NW-TT, the TSCTSF verifies if the UPF/NW-TT is configured to send (g)PTP messages to the UEs/DS-TTs.
If the Ntsctsf_TimeSynchronization_ConfigCreate request contains a temporal validity condition with a start-time and/or the stop-time that is in the future, the TSCTSF maintains the start-time and stop-time for the time synchronization service for the corresponding time synchronization configuration. If the start-time is in the past, the TSCTSF treats the request as if the time synchronization service was activated immediately. When the start-time is reached, the TSCTSF proceeds as described in this step above. When the stop-time is reached for active time synchronization service configuration, the TSCTSF proceeds as Ntsctsf_TimeSynchronization_ConfigDelete was received as described in clause 4.15.9.3.4.
If the Ntsctsf_TimeSynchronization_ConfigCreate request contains a spatial validity condition, then the TSCTSF performs the following operations:
- TSCTSF determines whether the TSCTSF has subscribed for the UE presence in Area of Interest composed by the TA(s) in the Time Synchronization Coverage Area. If not, the TSCTSF may either discover the AMF(s) serving the TA(s) comprising the Time Synchronization Coverage Area or discover the serving AMF(s) for each UE identified by a GPSI/SUPI as described in clause 5.27.1.10 of TS 23.501 [2].
Then the TSCTSF subscribes to the AMF(s) to receive notifications about the UE presence in Area of Interest using Namf_EventExposure operation with the corresponding event filters as described in clause 5.2.2.3 and in clause 5.3.4.4. of TS 23.501 [2]. The subscribed area of interest may be the same as the Time Synchronization Coverage Area or may be a subset of the Time Synchronization Coverage Area (e.g. a list of TAs) based on the latest known UE location.
- In order to ensure that a TAI list specifying the AoI for the AMF is aligned with UE's Registration Area (RA), the following steps shall be performed:
- When invoking the subscription with the AMF(s), the TSCTSF may provide an indication, a new Parameter Type = "Adjust AoI based on RA", that the AMF may adjust the received AoI depending on UE's RA.
- After receiving the Namf_EventExposure_Subscribe request from the TSCTSF with the Parameter Type = "Adjust AoI based on RA" and specified AoI, the AMF compares TAs from the AoI with the UE's Registration Area (RA). If the AoI includes one or more TA(s) that are part of UE's current RA, the AMF reports the UE is inside the Area Of Interest, otherwise the AMF reports the UE is outside the Area Of Interest, as described in Annex D.
- The AMF notifies the TSCTSF about the UE's presence in the AoI using the Namf_EventExposure_Notify service operation.
- Based on the notification from the AMF and the Time Synchronization Coverage Area determined in step 3, the TSCTSF determines whether to activate time synchronization service for this UE:
- If the UE location is within the Time Synchronization Coverage Area, the TSCTSF determines to activate time synchronization service for the UE/DS-TT creating the PTP port in DS-TT and adding it to the PTP instance. The TSCTSF uses the procedures described in clause K.2.2 of TS 23.501 [2] to configure and initialize the PTP instance in the DS-TT(s) and NW-TT.
- If the UE location is outside the Time Synchronization Coverage Area, the TSCTSF determines not to activate time synchronization service and not to create a PTP port in a DS-TT.
The TSCTSF uses the procedure in clause 4.15.9.4 to activate or modify the 5G access stratum time distribution for the UEs that are part of the impacted PTP instance.
7. The TSCTSF notifies the NEF (or AF) with the Ntsctsf_TimeSynchronization_ConfigUpdateNotify service operation, containing the PTP instance reference and the current state of the time synchronization service configuration.
If TSCTSF received spatial validity condition as part of the Ntsctsf_TimeSynchronization_ConfigCreate request, the TSCTSF notifies the NEF (or AF) with the Ntsctsf_TimeSynchronization_ConfigUpdateNotify service operation, whenever the UE moves in or out of the Area of Interest. The notification contains the PTP instance reference and the current state of the time synchronization service configuration.
8. The NEF notifies the AF with the Nnef_TimeSynchronization_ConfigUpdateNotify service operation, containing the PTP instance reference and the current state of the time synchronization service configuration.
9. Upon a change in the PTP instance in the DS-TT or NW-TT, the DS-TT or NW-TT report the change via PMIC or UMIC to the TSCTSF as described in clause K.2.2 of TS 23.501 [2].
Upon PDU Session release indication from a PCF, the TSCTSF removes the corresponding AF-session from the list of AF-sessions associated with the time synchronization configuration. The TSCTSF uses the procedure in clause 4.15.9.4 to remove the 5G access stratum time distribution parameters for the UE that is removed from the impacted PTP instance.
Upon PDU Session Establishment as defined clause 4.3.2.2.1, steps 10-13 in Figure 4.15.9.2-1 are repeated for the new PDU Session and the TSCTSF may notify the NEF (or AF) for the Time Synchronization capability event, optionally with the updated time synchronization capabilities, as described in step 12 in Figure 4.15.9.2-1.
NOTE 3: Upon receiving the notification, the NEF (or AF) can use the Ntsctsf_TimeSynchronization_ConfigUpdate service operation to add the DS-TT/UE to the existing PTP instance and corresponding time synchronization service configuration.
If TSCTSF received spatial validity condition as part of the Ntsctsf_TimeSynchronization_ConfigCreate request, upon a change in the UE presence in Area of Interest, the TSCTSF determines if the spatial validity condition shall trigger an activation or deactivation of the time synchronization service:
- If the UE has moved outside the Time Synchronization Coverage Area, then the TSCTSF temporarily removes the UE/DS-TT port from the PTP instance:
- If the DS-TT is configured to send Sync, Follow_Up and Announce messages for the related PTP instance, then TSCTSF deactivates the Grandmaster functionality in the DS-TT using PMIC (see also clause K.2.2.4 of TS 23.501 [2]).
- If NW-TT is configured to send Sync, Follow_Up and Announce messages on behalf of the DS-TT, then TSCTSF deactivates the Grandmaster functionality on behalf of the DS-TT in NW-TT using UMIC (see also clause K.2.2.4 of TS 23.501 [2]).
- If the UE has moved inside the Time Synchronization Coverage Area, then the TSCTSF adds the DS-TT PTP port to the PTP instance and also (re-)activates the Grandmaster functionality (described in clause K.2.2 of TS 23.501 [2]).
Upon a NG-RAN timing synchronization status update, the NG-RAN report the change via AMF or provisioned via OAM to the TSCTSF as described in clause 4.15.9.5.1.
Upon a UPF/NW-TT timing synchronization status update, the UPF/NW-TT timing synchronization status update is reported via UMIC or provisioned via OAM to the TSCTSF as described in clause 4.15.9.5.1.
If TSCTSF received a NG-RAN or UPF/NW-TT timing synchronization status update and the time synchronization service has a configured clock quality acceptance criteria for the UE, the TSCTSF determines whether the clock quality acceptance criteria can still be met:
- If the clock quality acceptance criteria can still be met, then TSCTSF may update the clockQuality information sent in Announce messages for the PTP instance using PMIC/UMIC reporting. The handling of Announce messages follows existing procedures as described in TS 23.501 [2].
- If the clock quality acceptance criteria cannot be met or can be met again, then TSCTSF informs the AF about the acceptance criteria result (e.g. acceptable/not acceptable).
10. The TSCTSF updates the state of the time synchronization configuration and may notify the NEF (or AF) with the Ntsctsf_TimeSynchronization_ConfigUpdateNotify service operation, containing the PTP instance reference and the updated state of the time synchronization service configuration, including whether there was a change in the UE's presence in the Time Synchronization Coverage Area (in cases when the AF has requested the service for a specific spatial validity condition), or the clock quality acceptance criteria result (in cases when the AF has requested the service with a clock quality acceptance criteria condition).
11. The NEF notifies the AF with the Nnef_TimeSynchronization_ConfigUpdateNotify service operation, containing the reference to the time synchronization service configuration (PTP instance reference) and the updated state of the time synchronization service configuration.
If the AF receives a clock quality acceptance criteria result, the AF may update the configuration of the PTP instance by updating the PTP instance sending a Nnef/Ntsctsf_TimeSynchronization_ConfigUpdate or Nnef/Ntsctsf_TimeSynchronization_ConfigDelete request, as described in clauses 4.15.9.3.3 and 4.15.9.3.4. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.9.3.3 Time synchronization service modification | Figure 4.15.9.3.3-1: Time synchronization service modification
1. To update an existing time synchronization service configuration of the PTP instance, the AF invokes a Nnef_TimeSynchronization_ConfigUpdate service operation providing the corresponding PTP instance reference.
2. The NEF invokes the Ntsctsf_TimeSynchronization_ConfigUpdate service operation with the corresponding TSCTSF.
The AF that is part of the operator's trust domain may invoke the services directly with the TSCTSF.
3. The TSCTSF checks whether the AF requested parameters in the update request comply with the stored Time Synchronization Subscription data as defined in clause 5.27.1.11 of TS 23.501 [2], for that, the TSCTSF retrieves the Time Synchronization Subscription data from UDM as defined in clause 4.15.9.2. If the Ntsctsf_TimeSynchronization_ConfigUpdate request includes or updates the Spatial validity condition and the Spatial validity condition is allowed per the subscription, the TSCTSF determines the UE's presence in the updated Spatial validity condition as specified in steps 3-7 of the time synchronization activation procedure in clause 4.15.9.3.2.
- If the AF updates the clock quality acceptance criteria in step 1, the TSCTSF determines the clock acceptance criteria upon a time synchronization failure/degradation/improvement as specified in step 9 of the time synchronization activation procedure in clause 4.15.9.3.2. If AF provides clock quality acceptance criteria in step 1, and it was not available when the service was activated, the TSCTSF subscribes for notifications for changes in the NG-RAN and UPF/NW-TT timing synchronization status, as described in clause 4.15.9.5.1:
- To determine the impacted UEs due to a timing synchronization status update reported by the NG-RAN, the TSCTSF follows the operation described in clause 5.27.1.12 of TS 23.501 [2].
- To determine the impacted UEs due to a timing synchronization status update reported by the UPF/NW-TT, the TSCTSF verifies if the UPF/NW-TT is configured to send (g)PTP messages to the UEs/DS-TTs.
4. The TSCTSF responds with the Ntsctsf_TimeSynchronization_ConfigUpdate response where the AF may include an indication that the UE(s) are (not) present in the Requested Coverage Area (in cases when the AF has requested the service for a specific area).
5. The NEF responds with the Nnef_TimeSynchronization_ConfigUpdate.
6-7. The TSCTSF uses the PTP instance reference included in the Ntsctsf_TimeSynchronization_ConfigUpdate request to identify the time synchronization service configuration and the corresponding AF sessions.
If the Ntsctsf_TimeSynchronization_ConfigUpdate request includes updated service parameters for the PTP instance and if the corresponding DS-TT(s) and NW-TT are suitable with the parameters (e.g. requested PTP instance type, transport protocol and PTP profile), the TSCTSF uses the procedures described in clause K.2.2 of TS 23.501 [2] to update the PTP instance(s) in the DS-TT(s) and NW-TT.
If the Ntsctsf_TimeSynchronization_ConfigUpdate request includes one or more UE identities to be added to the PTP instance, if the corresponding DS-TT(s) are suitable with the parameters (e.g. requested PTP instance type, transport protocol and PTP profile) in the time synchronization service configuration as identified by the PTP instance reference in the request:
- the TSCTSF adds the suitable AF-sessions to the list of AF-sessions that are associated with the time synchronization service configuration; and
- the TSCTSF uses the procedures described in clause K.2.2 of TS 23.501 [2] to initialize and activate the PTP instance(s) in the corresponding DS-TT(s).
- the TSCTSF uses the procedure in clause 4.15.9.4 to modify or activate the 5G access stratum time distribution for the UEs that are added to the impacted PTP instance.
If the Ntsctsf_TimeSynchronization_ConfigUpdate request includes one or more UE identities to be removed to the PTP instance, the TSCTSF removes the corresponding AF-sessions from the list of AF-sessions associated with the time synchronization configuration. The TSCTSF uses the procedure in clause 4.15.9.4 to remove the 5G access stratum time distribution parameters for the UEs that are removed from the impacted PTP instance.
8. The TSCTSF notifies the NEF (or AF) with the Ntsctsf_TimeSynchronization_ConfigUpdateNotify service operation, containing the PTP instance reference and the current state of the time synchronization service configuration, including and whether there was a change in the UE's presence in the Spatial validity condition (in cases when the AF has requested the service for a specific area) and/or whether there was a change in network's timing synchronization status as described in clause 5.27.1.12 of TS 23.501 [2] including the clock quality acceptance criteria result.
9. The NEF notifies the AF with the Nnef_TimeSynchronization_ConfigUpdateNotify service operation, containing the PTP instance reference, the current state of the time synchronization service configuration, network's time synchronization status and clock quality acceptance criteria result, if provided by Ntsctsf_TimeSynchronization_ConfigUpdateNotify. Based on the notification, the AF decides whether to modify the service configured for the UE of a PTP instance using Ntsctsf_TimeSynchronization_ConfigUpdate service, or whether to deactivate it using Nnef_TimeSynchronization_ConfigDelete service. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.9.3.4 Time synchronization service deactivation | Figure 4.15.9.3.4-1: Time synchronization service deactivation
1. To remove an existing time synchronization service configuration of the PTP instance, the AF invokes a Nnef_TimeSynchronization_ConfigDelete service operation providing the corresponding PTP instance reference.
2. The NEF invokes the Ntsctsf_TimeSynchronization_ConfigDelete service operation with the corresponding TSCTSF.
The AF that is part of operator's trust domain may invoke the services directly with TSCTSF.
The TSCTSF may also invoke the Ntsctsf_TimeSynchronization_ConfigDelete service operation when it determines (based on notifications from the AMF(s), see steps 3-7 of clause 4.15.9.3.2) that the UE(s) are outside the Spatial validity condition.
3. The TSCTSF responds with the Ntsctsf_TimeSynchronization_ConfigDelete response.
4. The NEF responds with the Nnef_TimeSynchronization_ConfigDelete response.
5-6. The TSCTSF uses the PTP instance reference included in the Ntsctsf_TimeSynchronization_ConfigDelete request to identify the time synchronization service configuration and the corresponding AF sessions. The TSCTSF uses the procedures described in clause K.2.2 of TS 23.501 [2] to disable the corresponding PTP instance(s) in the DS-TT(s) and NW-TT. The TSCTSF deletes the time synchronization service configuration for the respective PTP instance.
The TSCTSF uses the procedure in clause 4.15.9.4 to deactivate the 5G access stratum time distribution for the UEs that are part of the impacted PTP instance. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.9.4 Procedures for management of 5G access stratum time distribution | The AF can use the procedure to activate, update or delete the 5G access stratum time distribution for one UE or a group of UEs.
The AF may query the status of the 5G access stratum time distribution using Nnef_ASTI_Get service operation. The Nnef_ASTI_Create and Nnef_ASTI_Update request may contain the parameters as described in Table 4.15.9.4-1. The AF may subscribe to 5G access stratum time synchronization status simultaneously while creating or updating the ASTI service. The AF may receive 5G access stratum time distribution status updates via Nnef_ASTI_UpdateNotify service operation.
Table 4.15.9.4-1: Description of 5G access stratum time distribution parameters
Parameter
Description
5G access stratum time distribution indication (enable, disable)
Indicates that the access stratum time distribution via Uu reference point should be activated or deactivated for the associated UE identities.
Time synchronization error budget
Indicates the time synchronization error budget for the time synchronization service (as described in clause 5.27.1.9 of TS 23.501 [2]).
[optional]
Temporal Validity Condition
Indicates start-time and stop-time attributes that describe the time period when the time synchronization service is active.
[optional]
Spatial Validity Condition
Indicates a geographical area (e.g. a civic address or shapes) or a TA list in which time synchronization service is enabled (NOTE 1).
[optional]
Clock quality detail level
It indicates whether and which clock quality information to provide to the UE and can take one of the following values "clock quality metrics" or "acceptable/not acceptable indication".
[optional]
Clock quality acceptance criteria
It indicates acceptance criteria for the UE. It is defined based on the attributes specified in Table 5.27.1.12-1 of TS 23.501 [2]. The parameter shall be included if the "clock quality detail level" = "acceptable/not acceptable".
[conditional]
NOTE 1: A geographical area requested by an AF includes at least one tracking area (TA), i.e. the granularity is restricted to a TA level in this release of the specifications.
Figure 4.15.9.4-1: Management of 5G access stratum time information
1. AM Policy Association establishment as described in clause 4.16.1.
2. (When the procedure is triggered by the AF request to influence the 5G access stratum time distribution):
- To create a new request, the AF provides access stratum time distribution parameters to the NEF using the Nnef_ASTI_Create service operation (together with the AF identifier and potentially further inputs as specified in table 4.15.9.4-1), including a target (one UE identified by SUPI or GPSI, a group of UEs identified by an External Group Identifier. The NEF forwards the GPSI or the External Group Identifier to the TSCTSF by including it inside the Ntsctsf_ASTI_Create request.
- To update or remove an existing request, the AF invokes an Nnef_ASTI_Update or Nnef_ASTI_Delete service operation providing the corresponding time synchronization configuration id.
- To query the status of the access stratum time distribution, the AF invokes Nnef_ASTI_Get service operation providing the target (a list of UE identities (SUPI or GPSIs) or an External Group Identifier).
- If the AF includes clock quality detail level, the request creates a subscription at the NEF (for untrusted AF) or TSCTSF (for trusted AF) for notifications for the changes in 5G access stratum time distribution status.
- The create request creates also a subscription for the changes in 5G access stratum time distribution status. To subscribe to NG-RAN timing synchronization status updates, the AF can subscribe to notifications as described in clause 4.15.9.5.1.
The AF that is part of operator's trust domain may invoke the services directly with the TSCTSF and identifies the targeted UE(s) using SUPI(s) or an Internal Group Identifier.
If the request includes a spatial validity condition and the AF uses a geographical area as a spatial validity condition, the NEF transforms this information into 3GPP identifiers (e.g. TAI(s)) based on pre-configuration.
NOTE 1: Steps 1 and 2 can occur in any order.
NOTE 2: It is assumed that AFs within the operator's domain is aware of TAs that can be used to formulate a spatial validity condition for Time Synchronization Coverage Area (see clause 5.27.1.10 of TS 23.501 [2]).
3. (When the procedure is triggered by the AF request to influence the 5G access stratum time distribution):
- The NEF authorizes the request. After successful authorization, the NEF invokes the Ntsctsf_ASTI_Create/Update/Delete/Get service operation with the TSCTSF discovered and selected as described in clause 6.3.24 of TS 23.501 [2].
- The TSCTSF determines whether the targeted UE is part of a PTP instance in 5GS, if so the TSCTSF rejects the request (steps 4-11 are skipped).
- The TSCTSF checks whether the AF requested parameters for the targeted UE comply with the stored Time Synchronization Subscription Data as defined in clause 5.27.1.11 of TS 23.501 [2]. If the AF request targets a group of UEs, steps 4-5 mapping an External/Internal Group Identifier to SUPI(s) are executed before the compliance check in step 6a between UE's subscription and the AF requested parameters.
- The TSCTSF calculates the Uu time synchronization error budget as described in clause 5.27.1.9 of TS 23.501 [2]. This does not apply in case of Ntsctsf_ASTI_Delete service operation.
- If the AF/NEF includes clock quality detail level, the request creates a subscription at the TSCTSF for notifications for the changes in 5G access stratum time distribution status.
(When the procedure is triggered by PTP instance activation or modification in the TSCTSF):
- The TSCTSF calculates the Uu time synchronization error budget as described in clause 5.27.1.9 of TS 23.501 [2] for corresponding SUPIs that are part of the PTP instance.
4. (When the procedure is triggered by the AF request to influence the 5G access stratum time distribution):
If the AF targeted UE(s) are identified by GPSI(s) or an External/Internal Group Identifier, the TSCTSF uses the Nudm_SDM_Get request to retrieve the subscription information (SUPI(s)) from the UDM using each GPSI or the External Group Identifier as received from the NEF, or an Internal Group Identifier as provided by the AF directly.
5. (When the procedure is triggered by the AF request to influence the 5G access stratum time distribution):
The UDM provides the Nudm_SDM_Get response containing SUPI(s) that are mapped from each received GPSI or the External/Internal Group Identifier and identify the targeted UEs.
6a. (When the procedure is triggered by the AF request to influence the 5G access stratum time distribution):
The TSCTSF checks the AF request with the stored Time Synchronization Subscription data as described in clause 5.27.1.11 of TS 23.501 [2] for any targeted UE. If the AF is not authorized, steps 7-11 are skipped.
6b. (When the procedure is triggered by the AF request to influence the 5G access stratum time distribution):
If the Ntsctsf_ASTI_Create request in step 2 contains a spatial validity condition, then the TSCTSF performs the following operations:
- For each target UE, TSCTSF checks with the stored Time Synchronization Subscription data if the spatial validity condition is allowed. The TSCTSF determines whether the TSCTSF has subscribed for the UE presence in Area of Interest composed by the TAs list in the spatial validity condition. If not, the TSCTSF may either discover the AMF(s) serving in the TAs comprising the spatial validity condition or discovers the serving AMF(s) for each UE identified by a GPSI/SUPI as described in clause 5.27.1.10 of TS 23.501 [2].
Then the TSCTSF subscribes to the AMF(s) to receive notifications about the UE presence in Area of Interest using Namf_EventExposure operation with the corresponding event filters as described in clause 5.2.2.3 and in clause 5.3.4.4 of TS 23.501 [2]. The subscribed area of interest may be the same as the spatial validity condition or may be a subset of the spatial validity condition (e.g. a list of TAs) based on the latest known UE location.
- In order to ensure that a TAI list specifying the AoI for the AMF is aligned with UE's Registration Area (RA), the following steps shall be performed:
- When invoking the subscription with the AMF(s), the TSCTSF may provide an indication, a new Parameter Type = "Adjust AoI based on RA", that the AMF may adjust the received AoI depending on UE's RA.
- After receiving the Namf_EventExposure_Subscribe request from the TSCTSF with the Parameter Type = "Adjust AoI based on RA" and specified AoI, the AMF compares TAs from the AoI with the UE's Registration Area (RA). If the AoI includes one or more TA(s) that are part of UE's current RA, the AMF reports the UE is inside the Area Of Interest, otherwise the AMF reports the UE is outside the Area Of Interest, as described in Annex D.
- The AMF notifies the TSCTSF about the UE's presence in the AoI using the Namf_EventExposure_Notify service operation.
- Based on the notification from the AMF and spatial validity condition received in step 1, the TSCTSF determines whether to activate time synchronization service for this UE:
- If the UE location is within the spatial validity condition, the TSCTSF determines to enable access stratum time distribution for the UE.
- If the UE location is outside the spatial validity condition, the TSCTSF determines to disable access stratum time distribution for the UE.
If the Ntsctsf_ASTI_Create request in step 2 contains a temporal validity condition with a start-time and/or the stop-time that is in the future, the TSCTSF maintains the start-time and stop-time for the time synchronization service for the corresponding time synchronization configuration. If the start-time is in the past, the TSCTSF treats the request as if the time synchronization service was activated immediately. When the start-time is reached, the TSCTSF proceeds with the subsequent steps. When the stop-time is reached for active time synchronization service configuration, the TSCTSF proceeds as if Nnef_ASTI_Delete was received.
7. The TSCTSF searches the PCF for the UE using Nbsf_Management_Subscribe with a SUPI as an input parameter, indicating that it is searching for the PCF that handles the AM Policy Association of the UE.
8. The BSF provides to the TSCTSF the identity of the PCF for the UE for the requested SUPI via an Nbsf_Management_Notify operation. If matching entries already existed in the BSF when step 7 is performed, this shall be immediately reported to the TSCTSF.
9. The TSCTSF sends to the PCF for the UE its request for the AM policy of the UE (identified by SUPI) using Npcf_AMPolicyAuthorization request, containing the 5G access stratum time distribution indication (enable, disable), optionally the calculated Uu time synchronization error budget, optionally the clock quality detail level and clock quality acceptance criteria.
(When the procedure is triggered by PTP instance activation, modification, or deactivation in the TSCTSF):
The TSCTSF ensures the 5G access stratum time distribution for the UE is enabled if at least one of the PTP instances the UE is part of is active.
10. If the PCF receives multiple time synchronization error budgets for a given UE, then the PCF picks the most stringent budget. The PCF takes a policy decision and then the PCF may initiate an AM Policy Association Modification procedure for the UE as described in clause 4.16.2.2 to provide AMF the 5G access stratum time distribution parameters. As part of this:
- The AMF shall, if supported, store the 5G access stratum time distribution indication (enable, disable), the Uu time synchronization error budget, clock quality detail level and clock quality acceptance criteria, and the UE reconnection indication in the UE context in AMF;
If the AMF receives Uu time synchronization error budget in the Access Stratum Time Synchronization Service Authorization as part of the Access and Mobility Subscription data during registration procedure (see clause 4.28.2.1) and in the AM Policy, the AMF should use the value received from the AM policy.
If the UE has indicated a support for network reconnection due to RAN timing synchronization status change as described in clause 5.4.4a of TS 23.501 [2], and if the AMF received "clock quality detail level" as part of an AM Policy Association Modification procedure, the AMF sets the "UE reconnection indication" for the UE to connect to the network in the case when the UE later detects that the NG-RAN timing synchronization status has changed while the UE is in CM-IDLE or CM-CONNECTED with RRC_INACTIVE state. The AMF shall send the UE reconnection indication to the UE updating the UE configuration as defined in clause 4.2.4.2.
10a. The AMF shall send the 5G access stratum time distribution indication (enable, disable), the Uu time synchronization error budget, clock quality detail level and clock quality acceptance criteria when they are available, to NG-RAN during mobility registration, AM policy modification, Service Request, N2 Handover and Xn handover as specified in TS 38.413 [10]. The NG-RAN node shall, if supported, store the information in the UE Context. Based on this information, the NG-RAN node provides the 5GS access stratum time to the UE according to the Uu time synchronization error budget as provided by the TSCTSF (if supported by UE and NG-RAN) and NG-RAN provides timing synchronization status reports to the UE (as described in clause 4.15.9.5.2).
NOTE 3: This release of the specification assumes that deployments ensure that the targeted UEs and the NG-RAN nodes serving those UEs support Rel-17 propagation delay compensation as defined in TS 38.300 [9].
11. The PCF of the UE replies to the TSCTSF with the result of Npcf_AMPolicyAuthorization operation.
12. (When the procedure is triggered by the AF request to influence the 5G access stratum time distribution):
The TSCTSF responds the AF with the Ntsctsf_ASTI_Create/Update/Delete/Get service operation response.
13. (When the procedure is triggered by the AF request to influence the 5G access stratum time distribution):
The NEF informs the AF about the result of the Nnef_ASTI_Create/Update/Delete/Get service operation performed in step 2.
14. (When the procedure is triggered by the AF request to influence the 5G access stratum time distribution):
If TSCTSF received spatial validity condition as part of the Ntsctsf_ASTI_Create request in step 2, upon the reception of a change in the UE presence in Area of Interest notification, the TSCTSF determines if the spatial validity condition shall trigger an activation or deactivation of the access stratum time distribution:
- If the UE has moved inside the Time Synchronization Coverage Area, then the TSCTSF determines to enable access stratum time distribution for the UE.
- If the UE has moved outside the Time Synchronization Coverage Area, then the TSCTSF determines to disable access stratum time distribution for the UE.
If TSCTSF received clock quality acceptance criteria as part of the Ntsctsf_ASTI_Create request in step 2, upon a reception of a UE presence in Area of Interest notification, the TSCTSF determines if the UE is impacted correlating UE presence in Area of Interest notifications provided by the serving AMF and the timing synchronization status received (e.g. degradation, failure, recovery) as described in clause 5.27.1.12 of TS 23.501 [2].
15-16. (When the procedure is triggered by the AF request to influence the 5G access stratum time distribution):
If TSCTSF determines to modify access stratum time distribution for the UE in step 14 for which the AF requested access stratum time distribution, the TSCTSF notifies the service status to AF.
If the TSCTSF determines a change in the support of the clock quality acceptance criteria for the UE in step 14 for which the AF requested access stratum time distribution, the TSCTSF includes the clock quality acceptance criteria result to the notification to the AF. Based on this notification, the AF decides whether to modify the ASTI service configured for the UE using Ntsctsf_ASTI_Update service.
17. If there was a failure/degradation/improvement event in step 14, the NG-RAN provides timing synchronization status reports to the UE (as described in clause 4.15.9.5.2). |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.9.5 Procedures for subscription and management of network timing synchronization status monitoring | |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.9.5.1 Network timing synchronization status | Figure 4.15.9.5.1-1: Procedure for TSCTSF subscription to RAN and/or UPF/NW-TT timing synchronization status
0. The AF requests creation or modification of ASTI or PTP based time synchronization service as described in clauses 4.15.9.4 and 4.15.9.3 including clock quality detail level and clock quality acceptance criteria (if applicable) in the request.
If the request is received at the NEF, it checks whether the AF is authorized to send the request and forwards the request to the TSCTSF.
If network timing synchronization status reports are provisioned using node-level signalling via control plane, the TSCTSF determines the serving AMF(s) and the UPF/NW-TT nodes (if applicable) for the UE(s) that needs to initiate network timing synchronization status monitoring.
Otherwise, if network timing synchronizations status reports are provisioned via OAM, steps 1-4 and 7-9 are skipped.
1. (When the procedure is triggered by the AF request to influence the 5G access stratum time distribution or by PTP instance activation, modification):
Upon the reception of the clock quality detail level and clock quality acceptance criteria (if applicable) in the AF request in step 0, the TSCTSF needs to be subscribed to NG-RAN timing synchronization status updates at the NG-RAN nodes that may provision access stratum time distribution information to the target UE. NG-RAN timing synchronization status updates provisioning may be configured via AMF (with node level signalling as illustrated in steps 1-4).
2. The TSCTSF invokes an Namf_Communication_NonUeN2MessageTransfer request to the AMF. Inside this request, the TSCTSF includes an N2 Container indicating to the NG-RAN to start reporting TSS attributes and containing the TSCTSF Instance ID. Additionally, in this request the TSCTSF may specify TA(s) and/or NG-RAN node(s). Based on local configuration and/or TA or NG-RAN node information as received from the TSCTSF, the AMF may request some or all NG-RAN nodes in the TA(s) to perform the timing synchronizations status reporting.
3-4. The AMF sends the corresponding N2 messages to all applicable NG-RAN nodes. Upon receiving a response(s) from the NG-RAN node(s), the AMF includes in the Namf_Communication_NonUeN2MessageTransfer response or Namf_Communication_N2InfoNotify request to the TSCTSF a list of N2 Containers containing response messages from the NG-RAN nodes and the corresponding NG-RAN node identifier(s). The AMF may aggregate the response messages it receives from the NG-RAN nodes.
5. (When the procedure is triggered by the AF request for PTP instance activation, modification and if the UPF/NW-TT is involved in providing time information to DS-TT):
Upon the reception of the clock quality acceptance criteria in the AF request in step 0, the TSCTSF needs to be subscribed to UPF/NW-TT timing synchronization status updates at the UPF/NW-TT that may provision time information via PTP to the target UE. UPF/NW-TT timing synchronization status updates provisioning may be configured via OAM or via UMIC.
6. The RAN node and TSCTSF are pre-configured for the thresholds for each timing synchronization status attribute as described in clause 5.27.1.12 of TS 23.501 [2].
7-8. If the NG-RAN node detects a change on its timing synchronization status as described in clause 5.27.1.12 of TS 23.501 [2] and the timing synchronization status reporting is configured via the AMF in steps 1-3, the NG-RAN node notifies the AMF providing a NG-RAN timing synchronization status update. The update can contain the information elements listed in Table 5.27.1.12-1 of TS 23.501 [2], TSCTSF Instance ID and the scope of the timing synchronization status (as described in clause 5.27.1.12 of TS 23.501 [2]). The AMF forwards the latest received NG-RAN timing synchronization status update in the Namf_Communication_NonUeN2InfoNotify to the specific TSCTSF instance identified by the TSCTSF Instance ID as specified in step 2.
9. If the UPF/NW-TT detects a change on its timing synchronization status and timing synchronization status reporting is configured via UMIC in step 3, the UPF/NW-TT notifies the TSCTSF providing a UPF/NW-TT timing synchronization status update via UMIC. The update can contain the information elements listed in Table K.1-2 of TS 23.501 [2].
10. Upon the reception of a change in the NG-RAN and/or NW-TT timing synchronization status update, the TSCTSF shall determine if the UE is impacted and whether the clock quality acceptance criteria can still be met. For each scope of the timing synchronization status received from the RAN in step 6, if the status indicates degradation, TSCTSF may set the Area of Interest to gNB node ID(s) or Cell IDs in the scope of the timing synchronization status. The TSCTSF uses the resulted Area of Interest to subscribe for the UE presence in Area of Interest from the AMF that is serving the gNB node ID as described in clause 5.27.1.12 of TS 23.501 [2]. If the status indicates improvement, the TSCTSF may remove the corresponding scope from the subscription.
Upon reception of notification for the UE presence in the Area of Interest, if the TSCTSF determines that the UE is impacted for ASTI service, the TSCTSF performs steps 15-16 in clause 4.15.9.4 to notify the AF the acceptance criteria result.
Upon reception of notification for the UE presence in the Area of Interest, if the TSCTSF determines that the UE is impacted for PTP service, the TSCTSF performs steps 9-11 in clause 4.15.9.3.2 to notify the AF the acceptance criteria result.
11-14. If the TSCTSF determines to unsubscribe from the NG-RAN timing synchronization status updates, the following steps need to be taken:
11. The TSCTSF instance invokes the Namf_Communication_NonUeN2MessageTransfer request that includes its TSCTSF Instance ID and an N2 Container indicating to the NG-RAN(s) to stop reporting the TSS attributes.
12. The AMF sends the corresponding N2 message to the applicable NG-RAN nodes.
13. NG-RAN responds to the AMF, and the AMF provides a response to the Namf_Communication_NonUeN2MessageTransfer request from the TSCTSF instance.
NG-RAN stops reporting the TSS attributes to the AMF for the TSCTSF instance has sent the Namf_Communication_NonUeN2MessageTransfer with an N2 Container indicating to stop reporting NG-RAN timing synchronization status.
NG-RAN stops reporting the TSS attributes to the AMF once all the TSCTSF have requested to stop reporting.
14. After receiving an Namf_Communication_NonUeN2MessageTransfer response or Namf_Communication_N2InfoNotify request, the TSCTSF invokes the Namf_Communication_NonUeN2InfoUnSubscribe service operation to the AMF to unsubscribe from the NG-RAN timing synchronization status updates. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.9.5.2 5G access stratum time distribution status reporting to the UE | Figure 4.15.9.5.2-1: Procedure for reporting RAN timing synchronization status to subscribed UE
1. Creation or update of ASTI or PTP based time synchronization service (AF requested ASTI or PTP based time synchronization service is described in clauses 4.15.9.4 and 4.15.9.3; subscription based ASTI is described in clause 4.28.2.1) including in the request clock quality detail level indication and optionally the clock quality acceptance criteria. The clock quality level indication and optionally the clock quality acceptance criteria are sent to the NG-RAN and the UE reconnect indication is sent to the UE as described in clause 4.15.9.4.
2. The RAN node is pre-configured for the thresholds for each timing synchronization status attribute as described in clause 5.27.1.12 of TS 23.501 [2]. If there is a change on its primary source so that the thresholds are exceeded or met again, the NG-RAN node indicates the status via SIB information as described in clause 5.27.1.12 in TS 23.501 [2].
3. (When the UE is in RRC_INACTIVE or RRC_IDLE state):
If supported by the UE and If the UE determines, based on the reading of SIB9 information as described in clause 5.27.1.12 of TS 23.501 [2], a clock quality information update is available, and the AMF has provided the UE reconnection indication in step 10 of clause 4.15.9.4, the UE reconnects to the network as described in TS 24.501 [25].
4. (When the UE is in RRC_CONNECTED state):
The NG-RAN node notifies the UE providing clock quality information as configured in step 0 (i.e. sending clock quality metrics or acceptable/not acceptable indication) using unicast RRC signalling whenever the UE enters RRC_CONNECTED state and while the UE remains in RRC_CONNECTED, when any of the clock quality metrics or the acceptable/not acceptable indication for the UE changes. |
fe7d56f8e2b5a29b90140ea988c1e8a1 | 23.502 | 4.15.10 AF specific UE ID retrieval | This clause contains the detailed description and the procedures for the AF specific UE ID retrieval. The AF specific UE Identifier is represented by the External Identifier as defined in TS 23.003 [33].
NOTE 1: After retrieving AF specific UE ID, the AF can invoke NEF provided services (e.g. location monitoring).
NOTE 2: As described in sub-clauses of clause 4.3.6, NEF can invoke steps 3 to 6 of this procedure to get the assigned UE IP address, SUPI and DNN and S-NSSAI, and if HR-SBO applies, the DNN and S-NSSAI is the HPLMN's, and also an indication that the PDU Session is working in HR-SBO mode.
Figure 4.15.10-1: AF specific UE ID retrieval
1. AF requests to retrieve UE ID via the Nnef_UEId_Get service operation. The request message shall include UE address (IP address or MAC address) and AF Identifier, it may include, Port Number associated with the IP address, MTC Provider Information, Application Port ID, IP domain. The MTC Provider Information identifies the MTC Service Provider and/or MTC Application. If available, the AF may also provide the corresponding DNN and/or S-NSSAI.
NOTE 3: The MTC Provider Information can be used by any type of Service Providers (MTC or non-MTC) or Corporate or External Parties for, e.g. to distinguish their different customers.
NOTE 4: The combination of IP address and Port Number can be used by 5GC to derive the UE private IP address assigned by 5GC if the UE is behind a NAT, see steps 3-6 below.
NOTE 5: The Application Port ID is as defined in Nnef_Trigger_Delivery.
NOTE 6: The NEF can validate the provided MTC Provider Information and override it to a NEF selected MTC Provider Information based on configuration. How the NEF determines the MTC Provider Information, if not present, is left to implementation (e.g. based on the requesting AF).
2. The NEF authorizes the AF request. If the authorisation is not granted, the NEF replies to the AF with a Result value indicating authorisation failure; otherwise the NEF proceeds with the following steps. The NEF determines corresponding DNN and/or S-NSSAI information: this may have been provided by the AF or is determined by the NEF based on the requesting AF Identifier, MTC Provider Information.
If the NEF has received a Port Number in step 1, based on configuration, the NEF may recognize the address received is an IP address which is different from the actual private UE IP address assigned by 5GC, i.e. the UE is behind a NAT in UPF. If so, the NEF performs steps 3 to 6. Otherwise, steps 3 to 6 are skipped.
3. The NEF uses the Nnrf_NFDiscovery service operation to obtain the address of the UPF implementing NAT functionality for the UE (public) IP address. The request includes the UE (public) IP address. The NEF may also include the DNN and S-NSSAI associated with the AF ID, as well as the IP domain.
4. The NRF responds with a Nnrf_NFDiscovery response message including the UPF address of the UPF implementing NAT functionality for the UE (public) IP address.
5. The NEF uses the Nupf_GetUEPrivateIPaddrAndIdentifiers_Get service operation to request UE's (private) IP address from the UPF. The request includes the UE (public) IP address and Port Number and optionally IP domain, DNN and S-NSSAI associated with the AF ID.
6. The UPF responds with the Nupf_GetUEPrivateIPaddrAndIdentifiers_Get response message including UE's IP address and optionally, the IP domain. If the UPF has applied a NAT functionality, the UE's IP address returned by the UPF is the private UE IP address. If IP domain of UE private IP address is returned from UPF, it always takes precedence regardless of whether the IP domain information also provided by AF when it invokes Nnef_UEId_Get service operation. If UPF has the SUPI or GPSI of the UE, the UPF may return SUPI or GPSI and in this case steps 7-8 are skipped.
For HR-SBO case as described in clause 4.3.6.1 and in TS 23.548 [74], an indication that the UE PDU session is working in HR-SBO mode, SUPI and HPLMN DNN and S-NSSAI of the PDU session are also provided by UPF.
NOTE 7: The SUPI/GPSI is only available when the SMF provides it to the UPF for the purposes defined in TS 29.244 [69].
7-8. The NEF uses the Nbsf_Management_Discovery service operation with UE address and IP domain and /or DNN and/or S-NSSAI to retrieve the session binding information of the UE. If no SUPI is received in the session binding information from the BSF, the NEF replies to the AF with a Result value indicating that the UE ID is not available.
9. The NEF interacts with UDM to retrieve the AF specific UE Identifier via the Nudm_SDM_Get service operation. The request message includes SUPI or GPSI and at least one of Application Port ID, MTC Provider Information or AF Identifier.
10. The UDM responds to the NEF with an AF specific UE Identifier represented as an External Identifier for the UE which is uniquely associated with the Application Port ID, MTC provider Information and/or AF Identifier.
11. The NEF further responds to the AF with the information (including the AF specific UE Identifier represented as an External Identifier) received from the UDM.
4.15.10A MSISDN retrieval
This clause contains the detailed description and procedures for UE ID retrieval in the GPSI format of MSISDN as defined in TS 23.003 [33] by AFs. Depending on operator policy and local regulation, GPSI in MSISDN format may be exposed through the NEF to an authenticated and authorized AF. Depending on operator policy and local regulation, user consent may be required when exposing MSISDN. For the corresponding user consent check, one of the followings is used:
- if CAPIF, defined in TS 23.222 [54], is deployed and RNAA feature is supported, then RNAA, defined in clause 6.5.3 of TS 33.122 [95], is used; or
- the UDM is used to check user consent for MSISDN exposure.
The figure and procedures of clause 4.15.10 shall be applicable for MSISDN retrieval with the following differences:
- description of the AF specific UE ID retrieval is replaced as the MSISDN retrieval;
- description of the AF specific UE Identifier represented as an External Identifier is replaced as the UE Identifier in the GPSI form of MSISDN; and
- in step 10, the UDM checks the user consent for MSISDN exposure based on the operator policy.
4.15.10B MSISDN verification
This clause contains the detailed description and procedures for the NEF verification (matching) of a retrieved MSISDN from the UDM against an AF-provided MSISDN. Depending on the operator policy and local regulation, the NEF verification result of the MSISDN may also be exposed to an authenticated and authorized AF. Depending on operator policy and local regulation, user consent may be required for MSISDN verification as described in clause 4.15.10A.
The figure and procedures of clause 4.15.10 shall be applicable for MSISDN verification exposure with the following differences:
- description of the AF specific UE ID retrieval is replaced as the MSISDN verification exposure;
- description of the AF specific UE Identifier represented as an External Identifier is replaced as the UE Identifier in the GPSI form of MSISDN; and
- in step 1, the AF request message is replaced by Nnef_UEId_VerificationGet service operation and it shall also include GPSI in the form of MSISDN; and
- in step 11, the NEF responds with Nnef_UEId_VerificationGet response indicating "true" or "false" depending on whether the retrieved MSISDN from the UDM and the AF-provided MSISDN match or not (for additional information see clause 5.2.6.27.7). |
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