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dde9e2552d661348f67d747426d8c5c3 | 183 002 | 7.4 Specific procedures for V5 interfaces | V5 support is out of scope of an RGW, but may be an optional interface at an AGW. |
dde9e2552d661348f67d747426d8c5c3 | 183 002 | 7.4.1 General | Support of V5 interfaces (V5.1, V5.2) requires (see note) the use of a backhaul mechanism in conjunction with H.248. In particular H.248 shall be used for handling the adaptation of the 64-kbit/s bearer channels to RTP media streams, for applying tones and announcements, and for inband DTMF digit collection. NOTE: It is recognized that the AGW may also itself terminate the V5 signalling and then map it to IUA (for ISDN) and H.248 (for PSTN). |
dde9e2552d661348f67d747426d8c5c3 | 183 002 | 7.4.2 V5 signalling | An AGW shall support a signalling gateway according RFC 3807 [53] as a backhaul mechanism for transporting LAPV5 information to the MGC. |
dde9e2552d661348f67d747426d8c5c3 | 183 002 | 7.4.3 Handling of p- and f-type frames | Handling of p- and f-type frames is according clauses 7.3.2.2 and 7.3.2.3. 8 MG and MGC management and call-independent procedures Generic TISPAN Call-independent procedures are defined in a separate document (TR 183 025 [i.1]), which is an overall description for all ETSI defined H.248 profile specifications, i.e. TR 183 025 [i.1] provides a set of procedures that are available to each profile specification. For this profile, the set of applicable call-independent procedures is primarily given by the supported H.248 Command API capabilities for AuditValue (see clause 5.8.5), AuditCapabilities (see clause 5.8.6) and ServiceChange (see clause 5.8.8), and supported packages (e.g. for overload control), by each profile. In general, all call-independent procedures by TR 183 025 [i.1], as described in of clauses 5.8.5, 5.8.6, 5.8.8 and 5.14, shall be supported. The following clauses providing additional details for some selected call-independent procedures: • MG overload protection by MGC (clause 8.1); • MGC overload protection by MG (clause 8.1); • Monitoring of "quality metrics" for non-Root terminations (clause 8.2); • OAM-driven line tests (clause 8.3); • Measurements and supported H.248 statistics (clause 8.5); and • Conditional reporting capability of H.248 statistics (clause 8.4). |
dde9e2552d661348f67d747426d8c5c3 | 183 002 | 8.1 Overload control | MG overload control procedures are supported using the Overload Control package (ITU-T Recommendation H.248.11 [19]). In the case of MGC overload there are two mechanisms, the "notification behaviour" and "adaptive rate based" that are available to the MGC in order to regulate the traffic presented to it. ETSI ETSI TS 183 002 V3.3.1 (2009-08) 83 |
dde9e2552d661348f67d747426d8c5c3 | 183 002 | 8.1.1 Notification Behaviour | MGC will give preference to emergency calls and priority lines. Priority lines do not need any special H.248 handling since the MGC has the information and can use regular call setup procedures for those subscribers. Detection of emergency calls requires special handling whilst minimizing the MGC load. The special handling requires support of version 3. At detection of off-hook in the MG a Notify message is delivered to the MGC. The MGC checks its own congestion state in order to determine how to process the call. If the MGC is overloaded then the following procedures may be taken into effect. A Modify command is sent to the applicable termination in NULL context to start dialtone and monitor events which allow detection of emergency calls or non-emergency calls. The MGC uses two digit maps. The first digit map includes only the allowed emergency numbers (i.e. EmergencyDialPlan). The second digit map is used to identify if any non emergency number (i.e. NotEmergencyDialPlan) is dialled and automatically issue congestion tone. The NotifyBehaviour event parameter is set to "NeverNotify" for the second digit map. This ensures that the Notify messages reporting non emergency numbers are suppressed, while Notify messages reporting emergency numbers can progress as in normal conditions. An example of the Modify command is indicated below: Context = - { Modify = aln/1/1/1 { Events = 888 {xdd/xce {DigitMap = EmergencyDialPlan}, ; If emergency report to MGC {xdd/xce {DigitMap = {NotEmergencyDialPlan}, NotifyBehaviour = NeverNotify}}, Embed {Signals {cg/ct}}} ; If any other number issue congestion tone and report to MGC Signals {cg/dt}}} ; This applies dial tone prior to any digits being entered } } |
dde9e2552d661348f67d747426d8c5c3 | 183 002 | 8.1.2 Adaptive Rate Based | The adaptive rate based mechanism is defined in ES 283 039-4 [57] and allows the MGC to offset the load onto the AGWs during periods of MGC load. This is achieved using the "etsi_nr" package that enables the MGC to specify the "off-hook" rate that it can handle. When the MGC is no longer in overload, then the "Off-Hook" regulation in the AGW can be disabled using the "etsi_nr" package. Further procedural details can be found in ES 283 039-4 [57]. |
dde9e2552d661348f67d747426d8c5c3 | 183 002 | 8.2 IP QoS control and monitoring | The Quality of Service (QoS) of network connections can be monitored using the quality alert event of the network package. It is up to the MGC to set the threshold value that will trigger the notification of this event. The threshold value is expressed as a percentage of measured quality loss. The Media GateWay (MGW) does this by taking into account packet loss, jitter and delay, according to a provisioned algorithm. The Quality Alert Ceasing event of the Quality Alert Ceasing package enables the Media GateWay (MGW) to notify the MGC when the network connections return to an acceptable quality. |
dde9e2552d661348f67d747426d8c5c3 | 183 002 | 8.3 Testing of analog and digital lines | It shall be possible to trigger "metallic" line testing on physical terminations via the MG OAM interface. This profile does not support H.248-controlled line tests (e.g. line tests defined in ITU-T Recommendation H.248.17 [49]). A service change procedure shall be initiated by the MG, when a termination is placed in test. If the line test is required to be performed immediately, then the MG shall issue a ServiceChange with a method of "forced". The MGC shall not attempt to make any calls on the termination and release any existing context on the termination. If the line test is to be performed after release of any current connections, then the MG shall issue a ServiceChange with a method of "graceful". ETSI ETSI TS 183 002 V3.3.1 (2009-08) 84 |
dde9e2552d661348f67d747426d8c5c3 | 183 002 | 8.4 Real-Time Statistics Reporting | |
dde9e2552d661348f67d747426d8c5c3 | 183 002 | 8.4.1 Overview of conditional reporting | Normally a MGC obtains bearer related statistics through periodic auditing of the H.248 statistic descriptor or at the time of deletion of a stream or subtraction of a termination. However, in both cases, there is a time delay from when a reporting condition occurs on a MG (e.g. a statistic threshold being passed) and the MGC learning of the statistic. In many cases, such a delay is of no consequence. However, in some cases, the MGC may require to be immediately informed of a given statistical threshold condition occurring. In this case, the MGC must use the H.248.47 Statistic Conditional Reporting package [56]. This package may be applied to multiple statistics. The MGC should set the reporting thresholds and ranges as appropriate and must specify at least one "condition" for conditional reporting (i.e. the MGC must signal at least one condition per requested packageID/statisticID item). The exact statistics and reporting conditions are determined by operator configuration based on the application/service required. |
dde9e2552d661348f67d747426d8c5c3 | 183 002 | 8.4.2 Basic conditional reporting | Basic conditional reporting uses the protocol elements of the Statistic Conditional Reporting package version 1. This allows the definition of many, but limited reporting conditions. |
dde9e2552d661348f67d747426d8c5c3 | 183 002 | 8.4.3 Extended conditional reporting | Extended conditional reporting uses the protocol elements of the Statistic Conditional Reporting package version 2. This package allows in addition • to control whether a timestamp is reported with the detection of the (conditional reporting) events; and • extends the reporting conditions with value-based metric conditions. 8.5 Measurement of Resource Usage and Performance Metrics - Supported H.248 Statistics |
dde9e2552d661348f67d747426d8c5c3 | 183 002 | 8.5.1 Usage metering | Usage metering is supported by the statistics defined in the Network (nt), RTP (rtp) and RTP Application Data (rtpad) packages. Such statistics are notified to MGC when a termination is subtracted from a context (e.g. at the end of a session) or due to conditional reporting (see clause 8.4). They provide information about: 1) information about resource usage, e.g.: - the duration of the time a termination has been in a context, - the traffic volume, e.g. number of octets sent and received; 2) information about Grade of Service (GoS)/Quality of Service (GoS), e.g.: - the packet delay variation or packet transfer delay. The "number of octets" excludes all transport overhead (see clause E.11.4/H.248.1 Version 3), i.e. IP header is excluded in case of an IP-based H.248 Termination (see clause E.11.5.1.5/H.248.1). ETSI ETSI TS 183 002 V3.3.1 (2009-08) 85 |
dde9e2552d661348f67d747426d8c5c3 | 183 002 | 8.5.1.1 Traffic Volume related Statistics | Figure 5 provides an overview of different traffic volume related statistics. Traffic volume related statistics are only accessible by the nt and rtp packages in profile versions 1 and 2. Profile version 3 provides additional metrics. Application Level Framing Protocol RTP, UDPTL, … L3: IP L2 L4: UDP, TCP, … L1 e.g. audio codec Transport Protocol Network Protocol Application Data Principle protocol stack for H.248 IP Terminations transport overhead reported traffic volume b c d a e rtpad nt & rtp ipocs Figure 5: Overview of supported statistics - Traffic volume related statistics on different protocol layers |
dde9e2552d661348f67d747426d8c5c3 | 183 002 | 8.5.1.1.1 RTP Case (general) | Ephemeral terminations in this profile using RTP as application level framing protocol. Traffic volume based statistics may be accessed via the rtp package: • packet granularity: RTP packets sent and/or received; NOTE: Packet level statistics could already provide useful volume measurements in case of RTP packets with constant length). • octet granularity: RTP octets send/received statistics are coupled with nt package statistics, i.e. these statistics are also including RTP padding, RTP header information and UDP transport overheads. Such overhead is excluded in the RTP application data specific statistics (see clause 8.5.1.1.2). |
dde9e2552d661348f67d747426d8c5c3 | 183 002 | 8.5.1.1.2 RTP Case: application data | The RTP Application Data package provides support for explicit octet count statistics concerning media traffic, i.e. the RTP payload based traffic volume. |
dde9e2552d661348f67d747426d8c5c3 | 183 002 | 8.5.1.1.3 IP Case: network layer data | The IP layer octets count statistics package provides traffic volume statistics on IP layer for IP version 4 or 6. The H.248 ipocs package (see indication in figure 3) is not supported by this profile and previous versions. ETSI ETSI TS 183 002 V3.3.1 (2009-08) 86 |
dde9e2552d661348f67d747426d8c5c3 | 183 002 | 8.5.2 Statistics for reported metering pulses at analog lines | There is a PSTN supplementary service ("Advice of Charge" (AOC)) for reporting metering pulses towards PSTN terminals from network side. The PSTN AOC service is only applicable for H.248 analog line (ALN) terminations and provided by the amet package. The MG records reported metering pulses by: 1) a cumulative statistic (amet/cpc); and 2) an interval statistic (amet/pcslr). ETSI ETSI TS 183 002 V3.3.1 (2009-08) 87 Annex A (informative): Comparison with H.248 ARGW Profile Versions 1 and 2 A.1 General A.1.1 Version 2 Version 2 provides now all the package usage details, which were missing in profile version 1. A few number of further capabilities were added, see table A.1. The profile was also explicitly linked with TR 183 025 [i.1] with regards to the specification of relevant call-independent procedures. A.1.2 Version 3 Version 3 adds a number of new optional packages concerned with statistics and dial digit method detection plus an enhanced VBD capability. See annex A.3 for further details. A.2 Differences between H.248 ARGW Profiles Version 1 and Version 2 Table A.1 provides an overview of the differences between the H.248 ARGW Profiles Version 1 and Version 2. Table A.1: Difference between H.248 ARGW Profile Versions 1 and 2 Topic ES 283 002 (V1.1.3) [52] H.248 ARGW Profile Version 1 ES 283 002 (V2.1.0) [52] H.248 ARGW Profile Version 2 Required H.248 Version H.248 Version 2 IUA/SCTP encapsulation for Q.921 p-/f-type frames in IP domain Raw Frame Relay over Generic Routing Encapsulation for p-/f-type frames transport only IUA/SCTP based transport option in addition Support of V5 access networks Yes, via IUA (for ISDN) and H.248 (for PSTN) Yes, additionally via V5UA Support of MGC overload control Yes, notification behaviour based Yes, additionally adaptive rate based Packages ETSI Notification Rate Package No Yes Statistic Conditional Reporting Package No Yes ETSI ETSI TS 183 002 V3.3.1 (2009-08) 88 A.3 Differences between H.248 ARGW Profiles Version 2 and Version 3 Table A.2 provides an overview of the differences between the H.248 ARGW Profiles Version 2 and Version 3. Table A.2: Difference between H.248 ARGW Profile Version 2 and the present document Topic ES 283 002 (V2.1.0) [62] H.248 ARGW Profile Version 2 The present document H.248 ARGW Profile Version 3 Clarifications for Automatic Metering Statistics — New clause 8.5.2 on "statistics for reported metering pulses at analog lines" Voiceband Data service partial support of V.152 (see note) V.152 compliant service Packages Keepalive Request Package No Yes RTP Application Data Package No Yes Statistic Conditional Reporting Package V1 only. V2 New clauses 8.4.2 and 8.4.3. Digit Dialling Method Information for Extended Digit Maps Package No Yes NOTE: Two exceptions are allowed. ETSI ETSI TS 183 002 V3.3.1 (2009-08) 89 Annex B (informative): Bibliography • ETSI TR 101 183: "Public Switched Telephone Network (PSTN); Analogue ringing signals". • ETSI EN 300 403-1: "Integrated Services Digital Network (ISDN); Digital Subscriber Signalling System No. one (DSS1) protocol; Signalling network layer for circuit-mode basic call control; Part 1: Protocol specification [ITU-T Recommendation Q.931 (1993), modified]". • IETF RFC 2402: "IP Authentication Header". • IETF RFC 3550: "RTP: A Transport Protocol for Real-Time Applications". • IETF RFC 768: "User Datagram Protocol". ETSI ETSI TS 183 002 V3.3.1 (2009-08) 90 Annex C (informative): Change history Date WG Doc. CR Rev CAT Title / Comment Current Version New Version 26-05-08 17bTD101r1 Input draft from rapporteur with identical technical content with v2.1.0 3.0.0 30-05-08 17bTD102r1 001 B Optional Support of Application-level Statistics 3.0.0 3.0.1 30-05-08 17bTD103r1 002 D Clarifications for Automatic Metering Statistics 3.0.0 3.0.1 30-05-08 17bTD104r1 003 B Clarifications for Conditional Reporting of Statistics and support of Package Version 2 3.0.0 3.0.1 30-05-08 17bTD105r1 004 B Update reference for DiffServ Package 3.0.0 3.0.1 30-05-08 17bTD106r1 005 C Support of VBD service 3.0.0 3.0.1 30-05-08 17bTD107r1 006 B NAT Traversal support 3.0.0 3.0.1 30-05-08 17bTD108r1 007 F Comparison between Profile Versions 3.0.0 3.0.1 30-05-08 17bTD146r3 008 B H.248 ARG profile v3 RTP keep-alive packet 3.0.0 3.0.1 June 08 Creation of change history annex and editorial updates by ETSI Secretariat 3.0.1 3.0.2 July 08 Approval by plenary of CRs 001 to 008 3.0.2 3.1.0 26-11-08 19bTD19 009 r1 F Interworking between V.152-compliant and non-V.152 GWs 3.1.0 3.1.1 25-02-09 20WTD116 010 r2 F Addition of Dialling Method Discrimination Package 3.1.1 3.1.2 25-02-09 20WTD139 011 r1 F Clean-up of Annex A 3.1.1 3.1.2 25-02-09 20WTD140 012 r2 F Clean-up of References and kar package 3.1.1 3.1.2 25-02-09 20WTD141 013 r1 F Package usage overview for rtpad package 3.1.1 3.1.2 25-02-09 20WTD142 014 r1 F Check of package usage details for scr package 3.1.1 3.1.2 25-02-09 20WTD115 015 r2 F Further clarification of VBD handling 3.1.1 3.1.2 25-02-09 20WTD143 016 r2 F Autonomous VBD transitions (con't) 3.1.1 3.1.2 10-03-09 CRs 009 to 016 TB approved at TISPAN#20 3.1.2 3.2.0 18-03-09 20bTD117 017 r1 D Editorials in clause 6 3.2.0 3.2.1 18-03-09 20bTD250 018 r2 F Further clarifications to VBD text (VBD clause 6.2.4) 3.2.0 3.2.1 18-03-09 20bTD247 019 r2 F Further clarifications to VBD text (VBD clause 6.2.1) 3.2.0 3.2.1 Publication 3.2.1 3.3.1 ETSI ETSI TS 183 002 V3.3.1 (2009-08) 91 History Document history V1.1.1 August 2005 Publication as ES 283 002 V1.1.3 July 2007 Publication as ES 283 002 V2.1.0 March 2008 Publication as ES 283 002 V3.3.1 August 2009 Publication |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 1 Scope | The present document specifies the architecture and functions of a CDN Interconnection system, implementing the requirements defined in TS 102 990 [1]. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 2 References | References are either specific (identified by date of publication and/or edition number or version number) or non-specific. For specific references, only the cited version applies. For non-specific references, the latest version of the reference document (including any amendments) applies. Referenced documents which are not found to be publicly available in the expected location might be found at http://docbox.etsi.org/Reference. NOTE: While any hyperlinks included in this clause were valid at the time of publication, ETSI cannot guarantee their long term validity. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 2.1 Normative references | The following referenced documents are necessary for the application of the present document. [1] ETSI TS 102 990: "Media Content Distribution (MCD); CDN Interconnection, use cases and requirements". |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 2.2 Informative references | The following referenced documents are not necessary for the application of the present document but they assist the user with regard to a particular subject area. [i.1] ETSI TR 102 688-9: "Media Content Distribution (MCD); MCD framework; Part 9: Content Delivery Infrastructures (CDI)". [i.2] IETF RFC 6707: "Content Distribution Network Interconnection (CDNI) Problem Statement", September 2012. NOTE: Available at http://tools.ietf.org/html/rfc6707. [i.3] ATIS-0200003: "CDN Interconnection use case specification and high-level requirements". NOTE: Available at http://webstore.ansi.org/RecordDetail.aspx?sku=ATIS-0200003. [i.4] ISO/IEC 23009-1: "MPEG Dynamic Adaptive Streaming over HTTP (MPEG-DASH)". [i.5] ATIS-0200004: "CDN interconnection use cases and requirements for multicast-based content distribution". NOTE: Available at http://webstore.ansi.org/RecordDetail.aspx?sku=ATIS-0200004. [i.6] ETSI TS 182 019: "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); Content Delivery Network (CDN) architecture". ETSI ETSI TS 182 032 V1.1.1 (2013-04) 8 |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 3 Definitions and abbreviations | |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 3.1 Definitions | For the purposes of the present document, the following terms and definitions apply: NOTE: Some of the following definitions are from TS 182 019 [i.6] and TR 102 688-9 [i.1]. CDN Interconnection: interconnection between two CDNs, enabling the controlled distribution of content between those CDNs content delivery: act of delivering deployed content to a user Content Delivery Network (CDN): set of functions managing content acquired from content sources, through delivery to the user content acquisition: act of acquiring content from a content source content deployment: act of moving ingested content to one or more network entities, based on content deployment policies content distribution: act of moving content in and between CDNs content ingestion: act of introducing content (and associated data) into the Content Delivery Infrastructure content item: uniquely addressable content element in a CDN. NOTE: A content item is defined by the fact that it has its own Content Metadata associated with it. It is the object of content distribution and request routing operations in a CDN. Example of Content Items are a video file/stream, an audio file/stream, an image file or segmented content together with an associated manifest file. downstream: side of the CDN interconnection that is closest the Consumer logging: recording events related to content items, request routing and content distribution manifest file: file that describes the composition of segmented content metadata: data about content items and CDN network specifics reporting: providing access to recorded events related to content items, request routing and content distribution request routing: exchange of information be two CDNs to aid routing of requests of users for content segmented content: content composed of multiple files, or content composed of multiple streams, or content composed of one or more files and one or more streams upstream: side of the CDN interconnection that is closest to the Content Provider |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 3.2 Abbreviations | For the purposes of the present document, the following abbreviations apply: AAC Advanced Audio Coding ALF Asset Location Function AMT Automatic Multicast Tunnelling AS Autonomous System ATIS Alliance for Telecommunications Industry Solutions BGP Border Gateway Protocol CCF Cluster Controller Function CDF Content Delivery Function ETSI ETSI TS 182 032 V1.1.1 (2013-04) 9 CDN Content Delivery Network NOTE: Industry sometimes uses "Content Distribution Network". CDNCF Content Delivery Network Control Function CDN-I Content Delivery Network Interconnection CSF ATIS Cloud Services Forum dCDN Downstream Content Delivery Network DCF Distribution-of-Content Function dDCF Downstream Distribution-of-Content Function dICF Downstream Interconnection Control Function DNS Domain Name System DNSSEC Domain Name System Security Extensions dRCF Downstream Request-routing and Content-control Function DRM Digital Rights Management FLV Flash video GPS Global positioning system HD High Definition HDS HTTP Dynamic Streaming HLS HTTP Live Streaming HTML HyperText Markup Language HTTP Hypertext Transfer Protocol HTTPS HyperText Transfer Protocol Secure ICF Interconnection Control Function IP Internet Protocol MF Manifest File MPD Media Presentation Description MPEG Moving Picture Experts Group MSS Microsoft Media Server OCEAN Open ContEnt Aware Networks RCF Request-routing and Content-control Function REST Representational state transfer RTMP Real Time Messaging Protocol RTSP Real Time Streaming Protocol SDO Standards Developing Organization SLA Service Level Agreement SOAP Simple Object Access Protocol TISPAN Telecommunications and Internet converged Services and Protocols for Advanced Networking uCDN Upstream Content Delivery Network uDCF Upstream Distribution-of-Content Function UE User Equipment uICF Upstream Interconnection Control Function uRCF Upstream Request-routing and Content-control Function URI Uniform Resource Identifier URL Uniform Resource Locator WMV Windows Media Video |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 4 High-level overview | |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 4.1 CDN interconnection services and capabilities | CDNs are in general autonomous networks offering different services to their users. A CDN's primary function is to optimize content distribution and delivery. In addition to this primary function many CDNs chose to implement various other capabilities like content manipulation, digital rights management (DRM), intelligent handling of segmented content and others. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 10 Because of this variation, the present document specifies a basic set of capabilities that every interconnected CDN shall support. In addition to the basic capability set, the present document specifies an extended capability set, describing non-mandatory capabilities available for the CDN interconnection environment. The CDN interconnection shall support a capability exchange mechanism described later in the present document. Requirements defined in TS 102 990 [1] shall apply. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 4.2 CDN interconnection capabilities | Table 4.2.1 provides a table of all the capabilities available for CDN interconnection, grouped into the basic and extended capability set. It also mentions whether those capabilities are mandatory or optional. Table 4.2.1: Capability Overview Table Basic capability set Extended capability set Description Interconnection Control Mandatory Responsible for management of the peering relationship between two CDNs Request Routing Mandatory Capabilities responsible for making it possible for CDNs to direct client requests Content Distribution Mandatory Distribute content to other interconnected CDN Footprint Exchange Mandatory Responsible for announcing the network footprints the CDNs are offering to serve Metadata Exchange Mandatory Used to exchange content related information Content Status Exchange Mandatory Used for distribution of real-time status related to the content Report Exchange Mandatory Used for possibly delayed distribution of comprehensive information gathered during the content delivery process Capability Exchange Mandatory Capability to exchange information about the availability of extended capabilities in CDNs Metadata Defined Reporting Optional Capability of creating reports according to content provider parameters defined in metadata Content Integrity Control Optional Capability to maintain content integrity Content Adaptation Optional Capability to make content processing and adaptation within the CDN Multi-Segment Content Support Optional Capability to handle multi-segment content efficiently (for instance logging segment download sessions per session not just per segment) Content Access Control Optional Capability to define advanced content access control rules Content Security and DRM Optional Capability to use cryptographic technologies to maintain content security and DRM Custom Capability Support Optional Capability to support other (not standardized) capabilities |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 4.3 CDN-I basic capability set | Every CDN that wants to take part in CDN interconnection shall have a basic set of interconnection related capabilities. These capabilities give the CDN the ability to properly respond to requests coming from other CDNs. The capabilities included in the basic service set are listed in figure 4.3.1. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 11 Figure 4.3.1: Basic CDN-I capability set |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 4.4 CDN-I extended capability set | Whereas the basic capability set is sufficient for basic CDN interconnection many CDNs have additional capabilities that may not be available in all CDNs participating in the CDN federation. The presence of optional capabilities in the CDN federation requires those CDNs that wish to make use of those capabilities to have the capability to exchange information about the availability of extended capabilities in CDNs. This capability is called Capability Exchange and it is mandatory. Some of the capabilities included in the extended capability set are listed in figure 4.4.1. Figure 4.4.1: Extended CDN-I capability set ETSI ETSI TS 182 032 V1.1.1 (2013-04) 12 |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 4.5 Compliance | A CDN interconnection solution is compliant to the present document if the following points are fulfilled: • All mandatory services and features are implemented as specified in the present document. • If an optional service or feature is implemented, then it is implemented as specified in the present document. • If an optional service or feature is implemented, and the present document specifies multiple options, then it is implemented according to at least one or those options. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 5 Overview of functional entities | |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 5.1 Functional architecture for CDN interconnection services | The overall functional architecture for CDN interconnection service is shown in figure 5.1.1. The functional architecture is based on a multi-layer architecture that enable separate functionalities used for interconnection of CDNs that may involve up to 3 different level of functionalities and related reference points required. The first layer is responsible for content distribution, the second for controlling of content and request, and the third for the controlling of the interconnection itself. The CDN-I functional architecture should enable CDNs to agreed on a minimal level of interconnection, depending on available capabilities and their needs. In case of CDN peering both interconnected CDNs may play both the role of upstream and/or downstream CDN, depending of direction of content request. Figure 5.1.1: Functional architecture for CDN interconnection services |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 5.2 Functional entities | The Content Delivery Network contains one or more Distribution of Content Function (DCF) that can be grouped geographically or administratively in clusters and contains several delivery nodes (that distribute content to other CDN or to end user) hidden to other CDN. CDN shall contain one or more Request and Content Function (RCF) that process requests related to content distribution control and routing request. A CDN Interconnection Control Function (ICF) is responsible for the management of the interconnection. All CDN interconnection entities may support topology hiding and provide abstraction layer from internal CDN architecture. NOTE: Co-location of interconnection entities with existing CDN entities is possible. For example in case that one of the interconnected CDNs is based on ETSI CDN specification [i.6] there is possibility to collocate ICF with CDNCF, RCF with CCF and DCF with CDF. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 13 |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 5.2.1 CDN Interconnection Control Function (ICF) | A CDN Interconnection Control Function (ICF) shall manage, create, terminate and exchange CDN networks properties, status report required for CDN interconnection between two or more CDNs (CDN peers). An ICF contains following functionalities: • Footprint Exchange - enable CDNs exchange footprint information. • Capability Exchange - the upstream CDN gets information about capabilities of downstream CDN. This information can be used by Request Control Function. • Network Status Reporting - the upstream CDN gets status of downstream CDN network. This status is used by Request Control Function. If for example downstream network reports problems, upstream CDN will serve request by itself, or via other functional downstream CDN. • Network Logging - the downstream CDN sends logs to upstream CDN network. These logs are important for content provider and also for CDN administration. IP interconnection setup and service agreement between CDN providers shall be realized prior to logical CDN interconnection. Details of these activities are out of scope of the present document. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 5.2.2 Request and Content Control Function (RCF) | The Request and Content Control Function (RCF) is responsible for content control and request routing as well as exchanging metadata related to content control. The RCF contains following functionalities: • Metadata exchange function - Metadata are sent from upstream CDN to downstream CDN. Downstream CDN can then make room for content and can inform upstream CDN about content handling possibility. • Content request function - one CDN can request content from other CDN. Different request routing models can be used (e.g. push/pull model, chaining or redirecting requests). • Content status reporting - The Upstream CDN gets status of content from downstream CDN. This status can be than stored local database. Also events can be invoked on status change. Also Downstream CDN can inform upstream CDN when content status has been changed. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 5.2.3 Distribution of Content Function (DCF) | Distribution of Content Function (DCF) is responsible for distribution of content between CDNs in form of files, streams, metadata. The DCF contains following functionalities: • Transfer of file-based content. • Publication and streaming of stream-based content. • Content metadata distribution (if metadata distributed with content). |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 5.3 Reference points | |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 5.3.1 ICF - ICF (CDN-Ic) | This reference point is between two ICFs and it is used for controlling interconnection peer and transferred over this point information related to CDN capabilities and status, including footprint exchange, capability exchange, interconnection status reporting and network usage/performance logging. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 14 |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 5.3.2 RCF - RCF (CDN-Ir) | This reference point is between two CCFs and it is used for requesting content and to transfer content related information, including content metadata exchange, content requests and content status reporting. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 5.3.3 DCF - DCF (CDN-Id) | This reference point is between two DCFs. Content files, content streams and content related data (if distributed as part of content) are transferred over this point. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6 Procedures | This clause specifies CDN-I procedures. Clause 6.1 specifies the 3 main phases of interconnection. The following clauses describe specific procedures related to different capabilities that were agreed during the interconnection phase. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.1 CDN interconnection phases | The basic process of CDN interconnection may consist of three basic phases: • Interconnection establishment, during which the CDNs negotiate the interconnection. • Interconnection phase, during which the CDNs are fully interconnected and able to share their resources. • Interconnection release, during which the interconnection between the CDNs is released. The interconnection establishment and release phases may be omitted in systems that prefer manual provisioning and in that case interconnection establishment and configuration is performed statically by both interconnected CDN providers before interconnection phase itself. The procedure related to the interconnection establishment is described in clause 6.1.1, the procedure related to the interconnection phase is described in clause 6.1.2, and the procedure related to the interconnection release is described in clause 6.1.1. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.1.1 Interconnection establishment | The interconnection establishment is a procedure in which an uCDN and a dCDN begin with no relationship between each other and proceed by exchanging all the information needed to verify each other's identity and thus establish a secure communication channel between each other. This communication is between the ICFs of the CDNs and spans the first three steps of the procedure. The rest of the phase consists of three sub procedures in which the dCDN informs the uCDN about its capabilities, footprint and starts notifying it about its status. After the uCDN receives the first positive status exchange from the dCDN, it can safely assume that the dCDN is ready to process its requests. The conclusion of this phase is the establishment of communication between dRCF and uRCF and the whole CDN-I relationship moves to its interconnection phase. The interconnection establishment is an optional procedure, which is not used in case both CDN providers agree on static manual pre-provisioning of CDN interconnection, but if dynamic interconnection establishment is supported by both CDNs it should follow one of these procedures. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 15 Figure 6.1.1.1: Interconnection establishment NOTE 1: Prior to interconnection establishment procedure, IP interconnection and service level agreement between interconnected CDN providers and/or content provider are needed. The interconnection process should begin with the interconnection establishment. This interconnection establishment is defined by a procedure consisting of following steps: 1) The uCDN sends an interconnection request to the dCDN. This message is sent between the ICFs of the CDNs and consists of all the information the dCDN needs to decide whether to accept or deny the establishment of peering relationship with the uCDN. This information may include uCDN's CDN identifier, authentication data, required peering parameters and others. 2) After the dCDN receives an interconnection offer from an uCDN it analyses its contents and decides whether to deny it (sending an interconnection deny message and terminating the procedure) or accept it. If it decides to accept the offer then it sends an interconnection accept message that contains information that the uCDN can use to make a final decision about establishing the peering relationship with the dCDN. This information may include dCDN's CDN identifier, authentication data, required peering parameters and others. 3) After the uCDN receives an interconnection accept from a dCDN it analyses its contents and decides whether to deny it (sending an interconnection deny message and terminating the procedure) or confirm it. If it decides to confirm it then it sends an interconnection accept message indicating that the peering can begin. 4) After the interconnection is confirmed by the uCDN then the dCDN shall begin its first capability exchange procedure. 5) After the first capability exchange procedure is finished the dCDN shall begin its first footprint exchange procedure. 6) After the first footprint exchange procedure is finished the dCDN shall begin its first status exchange procedure. NOTE 2: This procedure may be repeated if there are multiple ICFs to be interconnected between the two CDNs. Both the CDNs should then proceed to the interconnection phase. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.1.2 Interconnection phase | The second phase is simply called interconnection phase. In interconnection phase shall be both CDNs already fully interconnected and through their interconnection interfaces ICFs and RCFs. Interconnection interfaces are fully useable by both CDNs and agreed capabilities accessible over CDN interconnection. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 16 concurrent subprocedures Figure 6.1.2.1: Interconnection phase The general procedure of the interconnection phase consists of concurrent executions of multiple separate procedures. These procedures are described in other sub-clauses of this clause, beginning with clause 6.2. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.1.3 Interconnection release | The interconnection release is a phase that begins when an uCDN or a dCDN decides to release a CDN peering relationship with each other (for a specific ICF-ICF relation, and associated RCF-RCF relations). This means that the procedure has two variants, depending on whether it was initiated by the uCDN or the dCDN. In both cases it concludes the interconnection relationship by cleanly finishing all outstanding actions between the two CDNs. The interconnection release is an optional procedure, which is not used in case CDN providers agree on static manual pre-provisioning of CDN interconnection, but if dynamic interconnection establishment is supported by both CDNs it should follow one of these procedures. The uCDN initiated procedure for this consists of following steps, shown in figure 6.1.3.1. Figure 6.1.3.1: uCDN-initiated interconnection release ETSI ETSI TS 182 032 V1.1.1 (2013-04) 17 1) The uCDN stops redirecting clients to the dCDN. 2) After the last client redirect is finished it sends the release request message to the dCDN. 3) The dICF immediately sends an acknowledgement. 4) After receiving the release request, the dCDN also stops distributing content from the uCDN. 5) The dCDN then waits until all outstanding reports are delivered. 6) The dCDN informs the uCDN about this event using the release confirm message. 7) The uCDN sends back acknowledgment message. After this both CDNs can fully disband the interconnection relationship and release all related resources. The dCDN initiated procedure for this consists of following steps, shown in figure 6.1.3.2. Figure 6.1.3.2: dCDN-initiated interconnection release The dCDN initiated procedure for this consists of following steps: 1) The dICF sends a release request message to the uICF. 2) The uCDN stops redirecting clients to the dCDN. 3) After the last client redirect is finished uICF sends the release accept message to the dICF. 4) After receiving the release request, the dCDN stops distributing content from the uCDN. 5) The dICF then waits until all outstanding reports are delivered. 6) The dICF informs the uICF about this event using the termination confirm message. 7) The uCDN sends an acknowledgement. After this both CDNs can fully disbanded the interconnection relationship and release all related resources. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 18 |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.2 Content distribution | |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.2.1 General | This clause provides procedures for content distribution: • Content distribution control, the initiation of content exchange. • Content exchange, the actually transfer or streaming of content between the interconnecting CDNs. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.2.2 Content distribution control | |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.2.2.1 General | This clause provides procedures for content distribution control: • Content distribution. • Content deletion. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.2.2.2 Upstream-initiated content distribution | Figure 6.2.2.2.1 shows the procedure for upstream-initiated content distribution from the uCDN to the dCDN. The two CDNs should be interconnected. NOTE 1: Upstream-initiated content distribution is typically used for the prepositioning of files or streams. Figure 6.2.2.2.1: Upstream-initiated content distribution The procedure has the following steps: 1) The uRCF is triggered to initiate content distribution. It selects a dCDN and makes sure that the capabilities of the dCDN match with the capability requirements of the content that the uCDN wants to distribute. 2) The uRCF selects a uDCF. It may communicate about this with the selected uDCF. 2. 3. 4. 5. 7. 8. 9. dDCF uRCF dRCF uDCF 1. Trigger 6. Content Exchange, see clause 6.1.3 10. Content Exchange, see clause 6.1.3 ETSI ETSI TS 182 032 V1.1.1 (2013-04) 19 NOTE 2: The communication between uRCF and uDCF is CDN internal. It is not specified in the present document. NOTE 3: The uDCF may be located in the Upstream CDN domain or in the Content Provider domain. The latter option saves resources in the Upstream CDN domain. 3) The uRCF sends a request to the dRCF for content distribution. The request contains the contentID of the content item that is to be distributed, the address of the selected uDCF and optionally other information, like a token for authentication purposes, or a DRM flag to indicate that DRM procedures apply (see also clause 6.6.2). 4) The dRCF returns a response, acknowledging the request. The response should contain an address or URI to which future UE request for the content item should be redirected. The dRCF could also reject the request. 5) The dRCF selects one or more dDCFs. It instructs the selected dDCF(s) to perform a content exchange. NOTE 4: The communication between dRCF and dDCF is CDN internal. It is not specified in the present document. 6) The selected dDCF performs a content exchange with the selected uDCF. The content exchange is specified in clause 6.2.3. 7) The dDCF informs the dRCF when the content exchange has completed. NOTE 5: The communication between dDCF and dRCF is CDN internal. It is not specified in the present document. 8) The dRCF informs the uRCF that the content is available for delivery by the Downstream CDN. 9) The uRCF returns an acknowledgement. 10) There may be subsequent content exchanges for the identified content item, where other DCF(s) retrieve the same content item. After step 9, the uCDN can start directing UE requests to the address or URI provided in step 4. NOTE 6: Communication with the UE is not described in the present document. NOTE 7: This procedure can be used in a way that the dCDN retrieves a content item only once, and it takes care of its internal distribution. This procedure can also be used in a way that the same or other dDCFs retrieve a content item multiple times, e.g. because of implemented caching strategies (least recently used, least frequently used, etc). NOTE 8: The dCDN can hide its internal topology towards the uCDN by always using the same limited group of dDCFs to retrieve content items from the uCDN, and performing further content distribution within the dCDN internally. Similarly, the uCDN can hide its internal topology by always using the same limited group of uDCFs to distribute content items to the dCDN. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.2.2.3 Downstream-initiated content distribution | Figure 6.2.2.3.1 shows the procedure for downstream-initiated content distribution from the uCDN to the dCDN. The procedure is used when the dCDN needs to know from where to retrieve an identified content item from the uCDN. NOTE 1: Downstream-initiated content distribution is typically used for cases where the distribution of content files or streams between the two CDNs is postponed until there is an actual user request. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 20 Figure 6.2.2.3.1: Downstream-initiated content distribution The procedure has the following steps: 1) The dRCF is triggered to initiate content distribution for an identified content item. 2) The dRCF sends a request to the uRCF. There includes the contentID of the content item. 3) The uRCF selects a uDCF. It may communicate about this with the selected uDCF. NOTE 2: The communication between uRCF and uDCF is CDN internal. It is not specified in the present document. 4) The selected uRCF responds to the dRCF. The response includes the location of the selected uDCF and optionally other information, like a token for authentication purposes, or a DRM flag to indicate that DRM procedures apply (see also clause 6.6.2). The uRCF could also reject the request. 5) The dRCF selects a dDCF and triggers it for a content exchange. NOTE 3: The communication between uRCF and uDCF is CDN internal. It is not specified in the present document. 6) The content exchange is specified in clause 6.2.3. 7) There may be subsequent content exchanges for the identified content item, where other DCF(s) retrieve the same content item. After step 6, the dCDN can start delivering the content item to Ues that have been redirected to the dCDN. NOTE 4: Communication with the UE is not described in the present document. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.2.2.4 Upstream-initiated content deletion | Figure 6.2.2.4.1 shows the procedure for upstream-initiated content deletion in the dCDN. NOTE 1: Upstream-initiated content deletion is typically performed at the request of a Content Provider to make sure that content is no longer available after a point in time. 2. dDCF uRCF dRCF uDCF 1. Trigger 6. Content Exchange, see clause 6.1.3 3. 4. 5. 7. Content Exchange, see clause 6.1.3 ETSI ETSI TS 182 032 V1.1.1 (2013-04) 21 Figure 6.2.2.4.1: Upstream-initiated content deletion The procedure has the following steps: 1) The uRCF is triggered to initiate content deletion. It should stop the request routing for the content item to the dCDN. 2) The uRCF sends a request to the dRCF to delete content. The request includes the contentID of the to-be- deleted content and a time-out parameter. 3) The dRCF returns an acknowledgement. 4) There are dCDN-internal communications and action to delete the identified content item. The dCDN should stop accepting new delivery requests for the content item. After the time-out, specified by the time-out parameter, it should actively stop/release all still on-going deliveries of the content item. If the content item is a stream, then clause 6.2.3.4 applies. NOTE 2: The dCDN-internal communications and actions are not specified in the present document. 5) The dRCF conforms the successful deletion of the content to the uRCF, see clause 6.2.2.5. After completion of this procedure, there shall be no further content exchanges for the deleted content. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.2.2.5 Downstream notification of content deletion | Figure 6.2.2.5.1 shows the procedure for downstream notification of content deletion. Figure 6.2.2.5.1: Downstream notification of content deletion The procedure has the following steps: 1) The dRCF is triggered to send a notification of content deletion. The dRCF may be triggered when all instances of a particular content file or stream are deleted in the dCDN. The dRCF shall be triggered if the content deletion is the result of an upstream-initiated content deletion as specified in clause 6.2.2.4. 3. 2. dDCF uRCF dRCF uDCF 1. Trigger 2. 3. dDCF uRCF dRCF uDCF 5. Notification of content deletion, see clause 6.1.2.5 1. Trigger 4. Content deletion, see also clause 6.1.3.4 ETSI ETSI TS 182 032 V1.1.1 (2013-04) 22 2) The dRCF sends a notification of content deletion to the uRCF. The notification includes the contentID of the deleted content item. 3) The uRCF returns an acknowledgement. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.2.3 Content exchange | |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.2.3.1 General | This clause provides procedures for content exchange. The following types of content may be exchanged: • Files. • Streams. • Segmented content. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.2.3.2 File transfer | Figure 6.2.3.2.1 shows the content-exchange procedure for file transfer. Figure 6.2.3.2.1: File transfer The procedure has the following steps: 1) The dDCF is triggered retrieve a file. The trigger includes information that enables the dDCF to identify and locate a selected uDCF. 2) The dDCF sends a retrieval request to the uDCF. 3) The uRCF authenticates the request and returns the requested file. NOTE: There may be more messages exchanged between the dDCF and uDCF, depending on the used protocol(s). |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.2.3.3 Stream set-up | Figure 6.2.3.3.1 shows the content-exchange procedure for stream set-up. 3. 2. dDCF uRCF dRCF uDCF 1. Trigger ETSI ETSI TS 182 032 V1.1.1 (2013-04) 23 Figure 6.2.3.3.1: Stream set-up The procedure has the following steps: 1) The dDCF is triggered to set up a stream. The trigger includes information that enables the dDCF to identify and locate a selected uDCF. 2) The dDCF sends a request to the uDCF to set up the stream. The request includes the contentID of the requested stream. 3) The uDCF authenticates the request and starts sending the requested stream to the dDCF. 4) The uDCF confirms to the dDCF that the stream has been set-up. NOTE: There may be more messages exchanged between the dDCF and uDCF, depending on the used protocol(s). |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.2.3.4 Stream release | Figure 6.2.3.4.1 shows the content-exchange procedure for stream release. Figure 6.2.3.4.1: Stream release The procedure has the following steps: 1) The dDCF is triggered to release a stream. 2) The dDCF sends a request to the uDCF to release the stream. 3) The uRCF stops sending the stream to the dDCF. 4) The uRCF confirms to the dDCF that the stream has been stopped. NOTE: There may be more messages exchanged between the dDCF and uDCF, depending on the used protocol(s). 3. 2. dDCF uRCF dRCF uDCF 1. Trigger 4. X 3. 2. dDCF uRCF dRCF uDCF 1. Trigger 4. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 24 |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.2.3.5 Segmented content | Segmented content is content composed of multiple files, or content composed of multiple streams, or content composed of one or more files and one or more streams. The composition of segmented content is described in an associated manifest file (MF). NOTE 1: The term "manifest file" has several synonyms, depending on the technology used. MPEG DASH [i.4], for example, uses the term Media Presentation Description (MPD). Figure 6.2.3.5.1 shows the content-exchange procedure for segmented content. Figure 6.2.3.5.1: Segmented content The procedure has the following steps: 1) The dDCF retrieves an MF from the uDCF, using the procedure of clause 6.2.3.2. The uCDN may decide to keep some URLs in the MF empty, in order to prevent the dCDN from retrieving the associated segments. NOTE 2: There may be several reasons why an uCDN would want to do this. If the dCDN is a mobile CDN, then it makes no sense to populate the dCDN with high-bitrate high-definition (HD) segments, that would never be delivered by the dCDN anyway. There may be cost considerations, where the uCDN would outsource the delivery of popular segments to the dCDN, and deliver the less popular segments from the uCDN itself. Especially for video clips, the early parts are much better watched than the later parts. Finally, the uCDN may want to deliver some segments itself for monitoring and logging purposes. NOTE 3: An MF with some empty URLs would typically only be used for content distribution and not be delivered to UEs. 2) The dDCF parses the manifest file and decides to initiate further content exchanges to retrieve the identified segments. 3) Further content exchange, see clause 6.2.3. 4) Optional further content exchange(s), see clause 6.2.3. NOTE 4: Whereas this clause shows how an MF (Manifest File) is distributed as a special type of content item, the MF could also be handled in a different way depending on bilateral agreements between the uCDN and dCDN. For example, depending on the type of MF (containing relative URLs, absolute URLs with redirection, or absolute URL without redirection), the MF could be distributed like any generic content item, the MF could be distributed like a special type of metadata, or the MF is not distributed to the dCDN at all. dDCF uRCF dRCF uDCF 3. Content Exchange, see clause 6.1.3 2. Manifest file 4. Content Exchange, see clause 6.1.3 1. Content exchange for manifest file, see clause 6.1.3.2 ETSI ETSI TS 182 032 V1.1.1 (2013-04) 25 |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.3 Request routing | |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.3.1 General | This clause provides procedures for request routing between two interconnected CDNs. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.3.2 Single-delivery request routing | Figure 6.3.2.1 shows the procedure for request routing for a single content-item delivery. Figure 6.3.2.1: Single-delivery request routing The procedure has the following steps: 1) The uRCF is triggered to initiate request routing, e.g. by an incoming content delivery request from a User Equipment (UE). 2) The uRCF send a request to the dRCF, with a contentID and optionally information (e.g. location or IP address) of the UE to which the identified content is intended to be delivered. 3) The dRCF may select a dDCF. It may communicate about this with the selected uDCF. NOTE 1: The communication between dRCF and dDCF is CDN internal. It is not specified in the present document. 4) The dRCF sends a response to the uRCF, with the dDCF address to which the UE content delivery request should be redirected. NOTE 2: No assumptions are made how that redirection takes place in the Upstream CDN domain. It may use HTTP redirect, DNS response, combination of both, or other. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.3.3 Multiple-delivery request routing | Figure 6.3.3.1 shows the procedure for request routing for multiple content items simultaneously. This procedure increases efficiency when there is a high intensity of request routing between the uCDN and dCDN. A specific case is segmented content, where the uCDN wants to fill-in a manifest file (MF) for directing individual segment requests directly to the proper dDCF. As the resulting MF, filled-in by the uCDN, is typically relatively small and UE-specific, it could be delivered to the UE by the uCDN directly, instead of having the MF delivered by the dCDN. 2. 4. 3. dDCF uRCF dRCF uDCF 1. Trigger ETSI ETSI TS 182 032 V1.1.1 (2013-04) 26 Figure 6.3.3.1: Multiple-delivery request routing The procedure has the following steps: 1) The uRCF is triggered to initiate request routing, e.g. by an incoming content delivery request from a User Equipment (UE) for segmented content. 2) The uRCF sends a request to the dRCF, with multiple contentIDs and optionally information (e.g. location or IP address) of the UE to which the identified content items are intended to be delivered. 3) The dRCF may select one or multiple dDCF(s) for the content delivery. It may communicate about this with the selected uDCF. NOTE: The communication between dRCF and dDCF is CDN internal. It is not specified in the present document. 4) The dRCF sends a response to the uRCF, with the dDCF address(es) to which the UE content delivery request should be redirected for the different identified content items. The uCDN can use this information for UE redirection and/or for filling in an MF. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.4 Reporting | |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.4.1 General | The reporting between CDNs is realized by two different procedures. The differences between them are explained below: • Upstream-initiated reporting is used by the upstream CDN to retrieve any information from the downstream CDN. This information may include up-to date delivery statistics and status , comprehensive historical logs or other information. The structure of these reports is not strictly defined by the present document. It only provides a way for the uCDN to inform the dCDN about the kind of data that it requests. • Downstream-initiated reporting is used when a downstream CDN needs to immediately inform the upstream CDN about a recent event related to a specific content item. The format and contents of these reports are strictly defined by the present document. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.4.2 Upstream-initiated reporting | The main role of the upstream-initiated reporting procedure is to make it possible for the uCDN to get access to the content-related information gathered by the dCDN while delivering the content to clients. This procedure shall be initiated by the uRCF to inform the dRCF about the fact that the uRCF requests specific information. The request sent by the uRCF shall include the description of the type of information required. Depending on the nature of the information the dRCF shall either respond either by directly returning the requested information or it shall return a URL that the uRCF will be able to use to access the requested information. This procedure is visualized in figure 6.4.2.1. 2. 4. 3. dDCF uRCF dRCF uDCF 1. Trigger ETSI ETSI TS 182 032 V1.1.1 (2013-04) 27 Figure 6.4.2.1: Upstream-initiated reporting procedure The procedure consists of following steps: 1) The uRCF sends a report request to the dRCF. This request indicates the description of information that the uRCF requires. 2) The dRCF shall respond to the uRCF with either the required information, or information about where it can be obtained. 3) The uRCF shall acknowledge the reception of the response. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.4.3 Downstream-initiated reporting | The role of the downstream-initiated reporting procedure is to inform the uCDN about a content-related event that happened within the dCDN. This procedure is visualized in figure 6.4.3.1. Figure 6.4.3.1: Downstream-initiated reporting procedure The procedure consists of following steps: 1) The dRCF sends a report message to the uRCF. 2) The uRCF shall acknowledge the reception of the report message. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.5 Interconnection Control Function Procedures | |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.5.1 General | These procedures allow to inform the uCDN about changes of specified capabilities/footprint/status of a dCDN. The information contained in these updates shall match the data models defined in clause 7. Examples of specific messages can be found in annex B. 1. Report request uRCF dRCF 2. Report response 3. Report ack uRCF dRCF 1. Report message 2. Report ack ETSI ETSI TS 182 032 V1.1.1 (2013-04) 28 |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.5.2 Capabilities exchange | The capability exchange is a procedure whose main goal is to inform the uCDN about the capabilities of a dCDN. The capability list is a data structure describing the list of capabilities (or features, services and their parameters) that the dCDN is willing to provide to uCDN. The capability exchange procedure is primarily used to exchange information about CDN capabilities over CDN interconnection. It can also be used for exchanging information about capabilities related to content delivery. These capabilities description are used to achieve interoperability between the CDNs compliant with the present document and enable interconnection with other CDNs that support just a subset or different sets of capabilities (e.g. comply only with basic capabilities specified in the IETF CDN-I standards [i.2]). If there is a CDN that does not support one of the methods of content delivery for example HTTP, it will still be able to interconnect and provide the delivery of content using other delivery methods that it does support, and will just need to communicate its capabilities over the capability exchange. For this reason CDNs compliant with the present document shall understand the meaning of the identifiers that represent these capabilities. Figure 6.5.2.1: Capability Exchange The capability exchange procedure is always initiated by the dCDN sending information about its capabilities to the uCDN. It consists of following steps: 1) The dCDN sends a capability message to the uCDN. This message contains the list of capabilities describing the dCDN. Examples of possible capabilities can be found in clause B.1 Metadata structure. 2) The uCDN acknowledges the reception of the capability message by sending a capability acknowledgement. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.5.3 Footprint exchange | The footprint exchange is a procedure whose main goal is to inform the uCDN about the footprint of a dCDN. The footprint is a data structure containing a list of network segments for which the dCDN can deliver content items for the uCDN. There are multiple methods that can be used to describe a network segment. The most basic one is an IP prefix. An IP prefix is a network number accompanied by a prefix length number. Geolocation, AS numbers and others are also viable candidates for network segment definitions. The basic rule is that any segment description can be used as long as there is a definitive agreement between the interconnected CDNs about how to map them to IP addresses. uICF dICF 1. Capability message 2. Capability acknowledgement ETSI ETSI TS 182 032 V1.1.1 (2013-04) 29 Figure 6.5.3.1: Footprint Exchange The footprint exchange procedure consists of following steps: 1) The dCDN sends a footprint database update to the uCDN. This message is triggered by a change of the footprint that dCDN wants to serve for uCDN. The update message contains only the changes from the previous version of the database and a checksum of the full database it is supposed to converge to after merging with previous version. 2) The uCDN merges the update with its footprint database related to the dCDN, calculates its checksum and compares it to a checksum received as part of the update message. If the checksum is ok then it skips over to step 5, otherwise it proceeds on step 3. 3) The uCDN requests the full footprint database from the source CDN. The full footprint database contains the whole data structure containing information about dCDN's footprint. 4) The dCDN sends the full footprint database to the uCDN. 5) The uCDN confirms the reception of the footprint update or database by sending a footprint exchange acknowledgement message. The footprint exchange process can start on step 1, 3 or 4 of the described procedure. If the process is triggered by a change in dCDN footprint database then it starts on step 1. If the uCDN triggers the process then it starts on step 3. If the process is triggered as the first footprint exchange then it starts on step 4. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.5.4 Services status exchange | The status exchange is a procedure whose main goal is to inform the uCDN about the status of a dCDN. This procedure is specific in the fact that it can be triggered not only in reaction to a change of status in the dCDN but is also used as a keep alive mechanism. This means that even when the dCDN's status did not change it has to send a status message within a defined amount of time to let the uCDN know that the status is still valid. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 30 Figure 6.5.4.1: Service Status Exchange The status exchange procedure is always initiated by the dCDN sending information about its status to the uCDN. It consists of following steps: 1) The dCDN sends a status message to the target CDN. 2) The target CDN acknowledges reception of the status message by sending a status acknowledgement. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.6 DRM Procedures | |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.6.1 General | These procedures are used when the CDN interconnection is involved in the DRM for content delivery. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.6.2 Flagging CDN content for DRM | An uCDN can flag to a dCDN that DRM procedures should be applied for a specific content item. This is flagged during content distribution. In case of upstream-initiated content distribution, step 3 of clause 6.2.2.2 includes that DRM flag. In case of downstream-initiated content distribution, step 4 of clause 6.2.2.3 includes that DRM flag. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.6.3 Key exchange for DRM | These procedures are relevant if the dCDN would need to encrypt a content item for delivery to a specific UE. Different encryption for different UE provides an additional layer of protection against signal theft. The content item could be stored in plain format. There exist also DRM systems that enable the content to be stored in encrypted format, and where a key is used to re-encrypt or partially decrypt it into the UE-specific encryption without fully decrypting the content in the process. This protects the content item against content theft at the CDN. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.6.3.1 uCDN-initiated key exchange for DRM | Figure 6.6.3.1.1 shows the procedure for uCDN-initiated key exchange for DRM. It may be combined with the single- delivery request-routing procedure of clause 6.3.2. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 31 Figure 6.6.3.1.1: uCDN-initiated key exchange for DRM The procedure has the following steps: 1) The uRCF is triggered to perform a key exchange procedure. The trigger may be a delivery request from a UE for DRM-protected content. 2) The uRCF sends a key exchange message to the uDCF. This message contains a DRM-instruction identifier, a DRM key, a contentID identifying the content item and an identifier of the UE and/or transaction (e.g. IP address or token). The semantics of the DRM instruction identifier are bilaterally agreed between the uCDN and the dCDN. It is used to instruct the dCDN which DRM system and DRM procedures need to be applied. 3) The dRCF may communicate with one or more dDCF to pass the received information. NOTE: The communication between dRCF and dDCF is CDN internal. It is not specified in the present document. 4) The dRCF returns an acknowledgement. As the triggers and procedure are similar with single-delivery request routing (clause 6.3.2), the two procedures may be combined. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 6.6.3.2 dCDN-initiated key exchange for DRM | Figure 6.6.3.2.1 shows the procedure for dCDN-initiated key exchange for DRM. If the content distribution to the dCDN has not yet taken place, then this procedure may be combined with the procedure for downstream-initiated content distribution in clause 6.2.2.3. Figure 6.6.3.2.1: dCDN-initiated key exchange for DRM 2. dDCF uRCF dRCF uDCF 1. Trigger 3. 4. 2. dDCF uRCF dRCF uDCF 1. Trigger 4. 3. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 32 The procedure has the following steps: 1) The dRCF is triggered to perform a key exchange procedure. The may be a delivery request from a UE for DRM-protected content. 2) The dRCF sends a request message to the uRCF. This message contains a contentID identifying the content item and an identifier of the UE and/or transaction (e.g. IP address or token). 3) The uRCF responds with a message that contains a DRM key and optionally a DRM-instruction identifier. A DRM-instruction identifier would be passed, if it cannot be derived from the UE request. UE requests typically contain tokens for authentication purposes, and a DRM instruction could also have been encoded in the token. 4) The dRCF may communicate with one or more dDCF to pass the received information. NOTE: The communication between dRCF and dDCF is CDN internal. It is not specified in the present document. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 7 Data models | There are two categories of data models. 1) CDN related data models This category of data represents the information about a specific CDN network from the interconnection perspective. - CDN information contains basic data that is relevant to specific CDN. - CDN footprint defines a single footprint segment that is related to a specific CDN. - CDN capabilities describe the capabilities of a specific CDN within a specific footprint segment. 2) Content related data models This category describes the data models relevant to specific content items and their delivery. - Content related metadata data model includes all the basic information describing the content. - Content distribution reporting data model includes all the data related to the distribution status of a specific content. - Content request source data model includes all the data related to a source of content delivery request. - Content delivery reporting data model includes all the data related to delivery of a specific content. Annex D provides examples of such data models. NOTE: There were no IETF-specified inter-CDN data models available at the time of writing the present document. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 8 Security | This clause specifies all the security aspects used for CDN interconnection. Their main purpose is to make it provide a complete tool-set that can be used to make CDN interconnection into a secure environment while maintaining scalability and flexibility. Scalability is guaranteed by adhering to the architectural principles defined by the high-level architecture as described in clause 5 of the present document. It is also reinforced by the use of encryption protocols and techniques that can be easily accelerated by available hardware. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 33 Flexibility is achieved by making all the elements of CDN interconnection security optional and by not using any proprietary protocol or complicated solutions. All the technologies used are usually already implemented in production CDN environments so they will not have to be re-engineered for CDN-I environments. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 8.1 Security feature interoperability | Because all of the security features in CDN-I environments are optional it is important to define the means of interoperability between CDNs with different CDN-I security feature sets. This kind of interoperability is achieved by the means of capabilities, see clause 6.5.2. This means that every security feature is represented by a corresponding capability that is advertised to peer CDNs every time a CDN interconnection relationship is established. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 8.2 CDN interconnection service protection | The security of communication between CDN-I entities, as specified in clause 6, is achieved by using the SSL/TLS protocol to encrypt and authenticate all communication channels. In most scenarios this consists of using the HTTPS protocol instead of plain HTTP for CDN-I procedure messages. In some cases it may also mean using secure versions of content distribution protocols. The authenticity of peer party can be always reliably verified by checking the security certificate at the time of connection set-up. If the certificate is neither known nor signed by a trusted certification authority then the connection should not be established. If it is established, then it shall be considered untrustworthy. The method of establishing secure connection between two CDNs is described in clause 8.2.1. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 8.2.1 Secure CDN-I connection establishment | The establishment of a secure CDN-I connection should begin by trying to connect to the Interconnection Control Interface of a peer CDN via the HTTPS protocol, using procedures described in clause 6.1.1. If the connection can be established and the certificates are valid and considered trustworthy, then the connection between the interconnection control entities is assumed to be trusted. If it is not possible to connect to the interconnection control interface via HTTPS, then HTTP shall be used instead and the connection shall be considered untrusted. If the HTTPS connection can be achieved but the certificate cannot be verified then it can still be used but shall also be considered untrusted. The decision about whether interconnection establishment may continue even when the connection between interconnection control entities is untrusted shall be made according to a local security policy of a particular CDN (not defined by the present document). TLS/SSL contains the option of no encryption algorithm (NULL). This option shall not be used within the scope of the present document. After the Interconnection Control entities are successfully interconnected, a capability exchange takes place, see clause 6.5.2. If the capabilities of a peer CDN indicate that it can use trusted connection for communication between RCFs or DCFs then these may be bootstrapped using secured connections. If all such connections between two CDNs are established via secured protocols and all the certificates are valid then the communication between two CDNs shall be considered trusted. Secure CDN interconnection may be a requirement of a security policy of a specific CDN. It may also be a requirement of the content provider. In such scenario the content provider shall indicate this requirement by the means of a metadata parameter indicating that a specific content may only be distributed between CDNs that are interconnected via secure and trusted connections. |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 8.3 CDN interconnection content and metadata authenticity | The authenticity of content and its metadata shall be achieved by protecting integrity by means of the security certificates. Content and or its metadata can be signed with a private key belonging to the content provider. The certificate and checksum generated for authenticity, generated with the use of the content provider's private key, shall be included as a part of the metadata file. Any CDN that requires verifying the authenticity of a piece of content or its metadata should have access to an authority where it can verify the certificate included in the metadata file. An example of such authority may be the DNSSEC system. It may also suffice for the certificate to be signed by the uCDN's private key (which should already be trusted at time of such check). ETSI ETSI TS 182 032 V1.1.1 (2013-04) 34 |
a816caab598d1d98df7e0e65e42626c6 | 182 032 | 8.4 Security policy definition by content provider | It shall be possible for the content provider to define rules related to the security requirements of the content they want to provide. These rules should be indicated within the metadata file accompanying the content. The content provider should guarantee the authenticity and integrity of this metadata file by signing it with its private key and publishing its corresponding public key in a certificate so that it can be used for verification. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 35 Annex A (informative): Interfaces and Functions This informative annex provides insight of CDN interconnection interfaces under study by other SDOs and projects. It also provides an initial list of functions that should be supported by the CDN interconnection architecture. A.1 CDN interconnect interfaces under study CDN interconnection is being studied by several SDO and projects. This clause provides insight of CDN interconnection interfaces under study by those SDOs and projects. A.1.1 ETSI CDN Figure A.1.1.1 shows the reference points of the ETSI CDN architecture (TS 182 019 [i.6]). Figure A.1.1.1: Reference points in ETSI CDN The following are the horizontal interfaces that may be relevant for CDN interconnection: • ALF - ALF (Qq'). The Asset Location Function is a functional entity having the knowledge of the available content, the content location and others content parameters. The Qq' reference point between ALFs allows one ALF to query another about the addresses having the requested content. It can be considered a subset of the Qq reference point between CDNCF and ALF. This reference point may exist between two ALFs belonging to different CDNs. • CDNCF - CDNCF (Yq). The Content Delivery Network Controller Function the function which manages one or more [CDN] clusters. The Yq reference point is used to allow a CDNCF to proxy a request to another CDNCF for handling. This reference point may exist between two CDNCFs belonging to different ETSICDNs. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 36 • CDF-CDF (Cf). Tasks of Content Delivery Function are a.o. handling content delivery. The Cf reference point between CDF and CDF allows delivering content between the two CDFs for content distribution. The CDF is always instructed where to go to acquire content. This reference point may exist between two CDFs belonging to different ETSI CDNs. A.1.2 IETF CDN-I A.1.2.1 General The published CDN Interconnection Problem Statement document RFC 6707 [i.2] provides a rationale for CDN interconnection, CDN-I terminology and a basic architecture outline. That outline provides the following four interfaces: • CDN-I Control Interface • CDN-I Request Routing Interface • CDN-I Logging Interface • CDN-I Metadata Interface The CDN-I Control Interface is used primarily for bootstrapping of all the other interfaces and exchange of the static information related to the CDN. It also includes some of the basic content control functions of the interconnection. Some of these include content purge requests and also the initiation of a content pre-positioning process. The CDN-I Request Routing Interface is responsible for ensuring that all user requests can be redirected to the most appropriate node of the CDN federation. Other than the primary role of handling client request redirects, it also handles the exchange of CDN-I information needed to properly make the request routing decisions. The CDN-I Metadata Interface is responsible for proper distribution of content related metadata. This metadata may contain informative data related to the content but also technical rules that should be considered when the files are being delivered. The CDN-I Logging Interface is responsible for correct distribution of any logs and reports related to the delivery of the client from the dCDN to the client. A.1.2.2 IETF CDN-I compatibility with ETSI CDN-I This clause discusses compatibility between RFC 6707 [i.2] and the present document. As both the IETF specifications on CDN interconnection, and the ETSI ones are work-in-progress at the time of writing the present document, all statements in the present clause about mutual compatibility have an ephemeral nature. At the architectural level, the following mappings can be made. • The CDN-Ic reference point for interconnection control from the present document seems to map on the union of the CDN-I Control Interface and the CDN-I Logging Interface from RFC 6707 [i.2]. • The CDNr reference point for request routing and content distribution control from the present document seems to map on the CDN-I Request Routing Interface and CDN-I Metadata from RFC 6707 [i.2]. There are some mismatches, as the present document distinguishes content-item specific status reporting from generic logging, whereas RFC 6707 [i.2] has a single logging interface. There are differences in terminology. The term "metadata" in RFC 6707 seems to correspond to [data for] "content distribution control" in the present document. The term "acquisition" in RFC 6707 [i.2] seems to correspond to "content exchange" in the present document. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 37 A.1.3 ATIS CSF ATIS document 0200003 [i.3] provides CDN interconnection use case specification and high-level requirements. The document contains a picture showing the following interfaces between two carrier CDNs: • Operations & Customer Care: SLA/outages/ticketing/Special customer requests. • Back-Office: Provisioning, Logs, settlements. • Routing: Traffic distribution, load management, AMT Relay address. • Delivery: Features, Capacity reservation, Origin access, multicast sources/groups. • Network Interconnection: Access, Security. The ATIS document does not specify details of those interfaces. A.1.4 FP7 OCEAN The FP7 OCEAN project (http://www.ict-ocean.eu/) is studying among others CDN interconnection. A.2 Functionality of the CDN interconnection TS 102 990 [1] specifies use cases and requirements for CDN interconnection. This clause highlights some of the requirements to start architecture discussions. A.2.1 Content distribution, upstream or downstream initiated Mechanism(s) will be needed to control the movement content from the Upstream CDN to the Downstream CDN. Content movement can be initiated by either party: • Upstream CDN initiated: e.g. triggered by the Content Service Provider, the Upstream CDN may pre- provision (specific delivery servers of) the Downstream CDN with specific content. • Downstream CDN initiated: e.g. triggered by the first Consumer request for a specific content or by a cache miss, the Downstream CDN pulls the retrieves the content from (a specified origin server of) the Upstream CDN. Preferably, the mechanisms to do this are identical or very similar. Figure A.2.1.1 is an example of an inter-CDN content distribution flow. The dotted lines in the figure are CDN-internal flows, which are outside the scope of the present document. Most likely, a mechanism should be added for confirming that the distribution of content has taken place successfully. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 38 Figure A.2.1.1: Example of an inter-CDN content distribution flow A.2.2 File-based and stream-based content The CDN interconnection should support both file-based (e.g. content-on-demand) and stream-based (e.g. broadcast) content. This will lead into differences in content distribution and reporting. • File-based content has a specified end: - So the successful distribution of the full content can be signalled. - Reporting can be done on a per-file basis. • Stream-based content does not have a pre-determined end: - So only the successful set-up of publication points for stream relay can be signalled. - Reporting may be different. Adaptive streaming is a special case, as the content is file based, but the content does not need to have a pre-determined end, as the manifest file may be updated on a regular basis. It was also recognized by IETF WG CDN-I that adaptive streaming needs special attention. Multicast in the Downstream CDN may be another special case. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 39 A.2.3 Request routing, per request or not Both IETF and ATIS present a request-routing interface to ensure that the Downstream CDN can handle specific content delivery requests. The interface could be used on a per-user request basis, but that would be potentially inefficient and delay prone. It could also be used to exchange information for a group of requests, which is equivalent to a capability exchange. Effectively, this could be some sort of resource reservation by the Upstream CDN on (servers of) the Downstream CDN. A point of discussion is the level of detail that the interface can or should provide. Can the Upstream CDN for example reserve a specified amount of storage and streaming capacity in a specific Downstream CDN server? A.2.4 Reporting or logging Clause 6.8 of TS 102 990 [1] contains several requirements on pushing and pulling content status reports and transaction reports, and monitoring of on-going content delivery. Two approaches are possible: • Logging: specify only an interface and/or messages to exchange unprocessed log files. • Reporting: also specify (extensible) datamodel(s) for the summarized status and transaction reports. The former approach is the simplest and most detailed, whereas the latter approach is more rigorous and has a better separation of concerns. Especially in case of adaptive streaming, the former approach can lead to excessively sized log files. A.2.5 Security mechanisms TS 102 990 [1] requires security mechanism for among others: • Verification of the integrity of the content (unchanged, unmutilated) • Authentication of the content source • Authorization of content requests by Consumers - In particular, an "anti-deep-linking" mechanism is required • DRM-related requirements A.2.6 Content adaptation Content adaptation has been discussed in detail by IETF, resulting in a decision that IETF CDN-I rel.1 will not support content adaptation in any form. As TS 102 990 [1] has specified requirements on content adaptations, mechanisms are needed to support it. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 40 Annex B (informative): Datamodel analysis B.1 Metadata structure B.1.1 General Metadata represents any data that is related to a content and used by the CDNs in order to distribute it properly and effectively. This clause lists all the data that can be distributed using Metadata Exchange and groups it into several categories. B.1.2 CDN Blacklists/Whitelists This group of metadata includes the information about which CDNs can the content be distributed to. It indicates weather the content can be distributed to any CDN, any CDN but those listed in a blacklist or only those CDNs listed in a whitelist. B.1.3 Capabilities required for content delivery This group of metadata lists the capabilities that a CDN is required to have in order to be allowed to deliver the content. Such capabilities can be: • Delivery protocol support (HTTP, RTSP, RTMP, MMS/RTSP and others). • Delivery format support (HTML, WMV, H.264, AAC, FLV, MP3 and others). • Data protection support (HTTPS, Tokens, content access lists and others). • Delivery method support (multicast, unicast and others). B.1.4 Content Access Lists Content access lists are metadata that define which clients can the content be delivered to. It is a list structure very similar to standard network access lists starting with several rows of allow or deny statements and ending with a deny all or allow all statement. These statements have to be evaluated by the delivery node in order to decide whether a client request is to be honoured or not. There are multiple methods by which clients can be identified within the access lists. Some of them can be IP prefixes (whole networks or hosts), country identifies (matched to IPs using geo location), cookies, https credentials and others. B.1.5 Content Manipulation Policy This clause of metadata includes information about how can the content be manipulated by the CDN before it is delivered. Some of these parameters can be: • Ability to use specified delivery protocol. • Ability to use specified delivery format. • Codecs that can be used to reformat the content. • Codec parameters to be honoured: - Resolutions allowed. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 41 - Bandwidths allowed. - Key Frame frequencies allowed. - Others. • Ability to use specific delivery method. • Ability to re-encrypt content to different encryption. B.1.6 Multi-Segment related metadata This clause of metadata includes information related to content that is a segment of a larger group. This information can include: • Unique content group identifier. • A link to a manifest related in which the segment is linked. • Identifier of previous segment. • Actual segment number. • Identifier of next segment. • Total segment count. B.1.7 Security and DRM related metadata This clause contains security related data. Some of this data can include: • Certificates proving content originality. • Certificates and keys related to encryption functionality. • Certificates used for https authorization. • Checksums used to verify data integrity. • Certification authority certificates. B.1.8 Reporting related metadata This clause lists information about which logs and other information should be gathered when delivering the content. This metadata can indicate: • The need to format reports in a defined way. • The need to include specific information in the reports. • The need to send (or upload) reports directly to specified destinations. • The need to transfer reports in a specific way. • The need to encrypt reports using a specific method/key. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 42 Annex C (informative): Scenarios for using CDN-I procedures C.1 General Clause 6 of the present document specifies a set of independent procedures for CDN interconnection. This annex provides some examples how procedures can be used in combination to achieve different types of CDN interconnection. Clause C.2 describes the basic life-cycle of an interconnection between two CDNs. Clauses C.3, C.4 and C.5 describe multiple alternatives representing actual content delivery. They differ by the level of control and reporting that the CDNs are willing to exchange. C.2 Basic CDN Interconnection life-cycle In this scenario an interconnection is established between a uCDN and a dCDN. This interconnection is then used to deliver dCDN footprint and capability information to the uCDN and to bootstrap the other required interfaces. These are then used to distribute content to the dCDN. From that point the client requests can be redirected to the dCDN. As the dCDN completes client requests it gathers logs and reports describing the delivery process of specific pieces of content. It uses the request and content control interface to deliver this information back to the uCDN. In the end the uCDN initiates the termination of the CDN-I interconnection. The dCDN completes all outstanding client requests, delivers all related reporting information and terminates the interconnection. Figure C.2.1 describes this scenario through procedures. It lists the procedures in chronologic order and assigns them to the CDN that initiated their execution. ETSI ETSI TS 182 032 V1.1.1 (2013-04) 43 Figure C.2.1: Scenario basic CDN interconnection life-cycle C.3 Premium delivery of content Figure C.3.1 shows a procedure scenario aimed at premium delivery of content. The uCDN (on behalf of the Content Provider) is in full control of each individual delivery. The uCDN uses the upstream-initiated content distribution procedure (clause 6.2.2.2) to distribute content to the dCDN, and it waits until the dCDN confirms that it has fully received the content item. From that point, for each user request, the uCDN checks with the dCDN whether it can deliver the identified content item at the agreed quality, and it subsequently directs the user request to dCDN. The uCDN also requests the dCDN for reporting on the delivery of the content item to that user. This scenario is appropriate when the Content Provider requires for control of the premium content delivery. dCDN uCDN Footprint exchange, see clause 6.5.3 Interconnection establishment, see clause 6.1.1 Upstream-initiated content distribution, see clause 6.2.2.2 Repeat Bootstrap remaining interfaces Capability exchange, see clause 6.5.2 Downstream-initiated content distribution, see clause 6.2.2.3 OR Content exchange, see clause 6.2.3 Single-delivery request routing, see clause 6.3.2 or Upstream-initiated content deletion, see clause 6.2.2.4 Downstream-initiated content deletion, see clause 6.2.2.5 OR Upstream-initiated reporting, see clause 6.4.2 Downstream-initiated reporting, see clause 6.4.3 OR Interconnection release, see clause 6.1.3 ETSI ETSI TS 182 032 V1.1.1 (2013-04) 44 Figure C.3.1: Scenario for premium delivery of content. C.4 Managed delivery of content Figure C.4.1 shows a procedure scenario aimed at managed delivery of content. The uCDN (on behalf of the Content Provider) uses the CDN-I interfaces to manage the dCDN selection, but it relies on the dCDN for the quality of experience for actual delivery. On a regular basis, the uCDN receives footprint information from the dCDN. The uCDN directs delivery requests from a user to a dCDN that is selected on basis of footprint information (and possibly also other information, like capabilities). Upon a cache miss, the dCDN performs a downstream-initiated content distribution to get the to-be-delivered content in real time. The dCDN decides what and when to report to the uCDN. This scenario is practical when the uCDN and the dCDN have a high-speed link to quickly handle cache misses. Figure C.4.1: Scenario for managed delivery of content dCDN uCDN Downstream-initiated content distribution, see clause 6.2.2.3 Footprint exchange, see clause 6.5.3 Direct delivery request from user to dCDN Repeat Downstream-initiated reporting, see clause 6.4.3 dCDN uCDN Single-delivery request routing, see clause 6.3.2 Upstream-initiated content distribution, see clause 6.2.2.2 Delivery request from user Repeat Upstream-initiated reporting, see clause 6.4.2 ETSI ETSI TS 182 032 V1.1.1 (2013-04) 45 C.5 Best-effort delivery of content Figure C.5.1 shows a procedure scenario aimed at best-effort delivery of content. In this scenario, the uCDN just directs delivery requests from its users to the dCDN without any previous checks or content distribution. Upon a cache miss, the dCDN performs a downstream-initiated content distribution to get the to-be-delivered content in real time. This scenario is practical when the uCDN wishes to fully rely on the dCDN for delivery. Figure C.5.1: Scenario for best-effort delivery of content dCDN uCDN Repeat Downstream-initiated content distribution, see clause 6.2.2.3 Direct delivery request from user to dCDN ETSI ETSI TS 182 032 V1.1.1 (2013-04) 46 Annex D (informative): Datamodels This annex presents examples of data models that may be used for CDN interconnection. It represents a set of data that is sufficient to properly keep all the states required for execution of all the basic procedures described in clause 6 of the present document. D.1 CDN related data models This category of data represents the information about a specific CDN network from the interconnection perspective. • CDN information contains basic data that is relevant to specific CDN. • CDN footprint defines a single footprint segment that is related to a specific CDN. • CDN capabilities describe the capabilities of a specific CDN within a specific footprint segment. D.1.1 CDN information data model Key Group Value type Comment id Basic string Id of CDN name Basic string Name of CDN icfInterface Basic url Address of Interface for Interconnection exchange. (SOAP, REST, etc.) rcfInterface Basic url Address of Interface for Interconnection exchange. (SOAP, REST, etc.) D.1.2 CDN footprint data model Key Group Value type Comment footprintID Basic integer Footprint identifier footprintTYPE Basic string Defines the footprint type (ip prefix, geolocation, BGP AS number) CDN-ID Basic integer CDN identifier footprintDATA Basic string The variable containing footprint data (as defined n footprintTYPE) D.1.3 CDN Capabilities data model Key Group Value type Comment footprintID Basic integer Footprint identifier httpFileTransfer Basic boolean Describes the network's capability of delivering files via http streaming Basic boolean Describes the network's capability of delivering streams isAuthorization Basic authentication Basic string Coma separated list of mechanisms dynamicStreaming Extented Set of (HLS, HDS, MSS, DASH) Defines supported dynamic streaming methods ETSI ETSI TS 182 032 V1.1.1 (2013-04) 47 D.2 Content related data models This clause describes the data models relevant to specific content items and their delivery: • Content related metadata data model includes all the basic information describing the content. • Content distribution reporting data model includes all the data related to the distribution status of a specific content. • Content request source data model includes all the data related to a source of content delivery request. • Content delivery reporting data model includes all the data related to delivery of a specific content. D.2.1 Content related metadata data model Key Group Value type Comment id Basic string Content identification name Basic string Content name contentProvider Basic string Content provider identification description Basic string Content description contentType Basic string Content MIME type transferType Basic file/stream Content transfer type isInfinite Basic boolean Identifies live streams length Basic long Number of bytes, content contains of metadataVersion Basic timestamp Time when metadata was updated from content provider fileVersion Basic timestamp Time when content was updated from content provider adaptation Extended boolean Defines if content adaptation is allowed qosDelivery Extended structure Defines the qos parameters for content D.2.2 Content distribution reporting data model Key Group Value type Comment content ID Basic string ID of content distributionPoint Basic string Name of distribution point status Basic no, download, ready, waiting for undeploy Content status hit ratio Basic double Content-specific hit ratio deploymentTime Extended long Number of seconds transfer has taken D.2.3 Content request source data model Key Group Value type Comment identity Basic string ID of user is optional isMobile Basic boolean Detect if device is moving (from GPS position, IP change, ip Basic string Client IPv4 address ipV6 Basic string Client IPv6 address location Basic GPS Client location downloaded Extended long Number of bytes transferred towards requester ETSI ETSI TS 182 032 V1.1.1 (2013-04) 48 D.2.4 Content delivery reporting data model Is list of one or more entities of following class. Key Group Value type Comment contentID Basic string ID of content requestorID Basic string Name of distribution point startTime Basic timestamp Timestamp of operation start endTime Basic timestamp Timestamp of operation stop status Basic Progress, success, fail, interrupted, paused Status of operation at the stop time D.3 Data model entity relations This clause visualizes the relations between various data model entities of CDN interconnection. Figure D.3.1: CDN-I data model entity relations ETSI ETSI TS 182 032 V1.1.1 (2013-04) 49 History Document history V1.1.1 April 2013 Publication |
a95505b1e252f195bf707ee85ccce821 | 183 025 | 1 Scope | The purpose of the present document is to define guidelines with regard to the interaction of non-call related H.248 procedures and generic network management use cases and vice versa. More specifically, the interaction between the following is considered: • Control procedures at the H.248 interface. These are the procedures between Media Gateway Controllers (primary and secondary) and their associated Media Gateways (primary, and secondary if available). These procedures primarily utilize the H.248 ServiceChange and H.248 Audit procedures. • Management procedures at the management interface(s) of H.248 systems (i.e. both Media Gateway Controller and Media Gateway) to perform non call related tasks such as configuration management (start-up, capability change, maintenance locking) and fault management (failure handling). It is intended that these guidelines are then subsequently used in corresponding H.248 profiles to produce detailed non-call related procedures. At the current time, the existing set of ETSI H.248 profiles ( [i.1], [i.2], [i.3] and [i.4]) lack any such detailed procedures. Specific management systems, architectures and protocols are outside the scope of the present document; only the general requirements and Use Cases related to the management system shall be discussed. |
a95505b1e252f195bf707ee85ccce821 | 183 025 | 1.1 Applicability | The present document is applicable to any network element that exhibits a H.248 interface and a management interface (e.g. SNMP). The intent of the present document is to provide guidelines so as to facilitate a consistent set of behaviour for non-call related procedures in the related H.248 profile specifications. Due to the general nature of the present document, it is possible that some of the procedures herein will not be applicable to certain H.248 profiles - it is for a specific profile itself to define which procedures are mandatory/optional/not applicable. The present document assumes an IP-based transport for H.248 signalling. The IP transport may be provided by either UDP or SCTP. |
a95505b1e252f195bf707ee85ccce821 | 183 025 | 1.2 Relation to H.248 Standards | The present document is considered to be complementary to H.248 standards where there are discrepancies between the present document and the correspondent ITU-T Recommendation H.248 series Recommendations, the procedures of these ITU-T Recommendations (in particular ITU-T Recommendation H.248.1 [i.5] and its annex F on ServiceChange), take precedence over those described in the present document. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 8 |
a95505b1e252f195bf707ee85ccce821 | 183 025 | 2 References | References are either specific (identified by date of publication and/or edition number or version number) or non-specific. • For a specific reference, subsequent revisions do not apply. • Non-specific reference may be made only to a complete document or a part thereof and only in the following cases: - if it is accepted that it will be possible to use all future changes of the referenced document for the purposes of the referring document; - for informative references. Referenced documents which are not found to be publicly available in the expected location might be found at http://docbox.etsi.org/Reference. NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee their long term validity. |
a95505b1e252f195bf707ee85ccce821 | 183 025 | 2.1 Normative references | The following referenced documents are indispensable for the application of the present document. For dated references, only the edition cited applies. For non-specific references, the latest edition of the referenced document (including any amendments) applies. Not applicable. |
a95505b1e252f195bf707ee85ccce821 | 183 025 | 2.2 Informative references | The following referenced documents are not essential to the use of the present document but they assist the user with regard to a particular subject area. For non-specific references, the latest version of the referenced document (including any amendments) applies. [i.1] ETSI ES 283 002 (V1.1.1): "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); PSTN/ISDN Emulation Subsystem (PES); NGN Release 1 H.248 Profile for controlling Access and Residential Gateways". [i.2] ETSI ES 283 024 (V1.1.1): "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); PSTN/ISDN Emulation: H.248 Profile for controlling Trunking Media Gateways in the PSTN/ISDN Emulation Subsystem (PES); Protocol specification". [i.3] ETSI ES 283 018 (V1.1.1): "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); Resource and Admission Control: H.248 Profile for controlling Border Gateway Functions (BGF) in the Resource and Admission Control Subsystem (RACS); Protocol specification". [i.4] ETSI ES 283 031 (V1.1.1): "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); IP Multimedia: H.248 Profile for controlling Multimedia Resource Function Processors (MRFP) in the IP Multimedia System (IMS); Protocol specification". [i.5] ITU-T Recommendation H.248.1 (2005): "Gateway Control Protocol: Version 3". [i.6] ITU-T Recommendation H.248.10 (2001): "Gateway control protocol: Media Gateway Resource Congestion Handling package". [i.7] ITU-T Recommendation H.248.14 (2002): "Gateway control protocol: Inactivity timer package". ETSI ETSI TS 183 025 V2.5.1 (2009-04) 9 [i.8] ITU-T Recommendation H.248.11 (2002): "Gateway control protocol: Media Gateway Overload Control package". [i.9] ETSI ES 283 039-4 (V2.1.1): "Telecommunications and Internet converged Services and Protocols for Advanced Networking (TISPAN); NGN Overload Control Architecture; Part 4: Adaptative Control for the MGC". [i.10] ITU-T Recommendation H.248.40 (2007): "Gateway control protocol: Application Data Inactivity Detection package". [i.11] IETF RFC 4268: "Entity State MIB". [i.12] ITU-T Recommendation X.731: "Information technology - Open Systems Interconnection - Systems management: State management function". [i.13] ITU-T Recommendation H.248.8: " Gateway control protocol: Error code and service change reason description ". |
a95505b1e252f195bf707ee85ccce821 | 183 025 | 3 Definitions and abbreviations | |
a95505b1e252f195bf707ee85ccce821 | 183 025 | 3.1 Definitions | For the purposes of the present document, the following terms and definitions apply: control association: H.248 Control Association is defined in clause F.2/H.248.1 version 3 [i.5] H.248 entity: any primary or secondary MGC or MG may be also denoted as H.248 entity NOTE 1: An H.248 entity relates to a Functional Entity (FE), any implementation of an H.248 entity is mapping the functional entity on a Physical Entity (PE). NOTE 2: E.g. a virtual MG (VMG) is a H.248 FE. Multiple VMGs are realized in a single physical MG, which relates to an H.248 PE. NOTE 3: Physical entities are sometimes also denoted as "platform" or "processor". primary Media Gateway (MG): no explicit definition in H.248 NOTE: The primary MG is rather implicitly defined. See mainly ITU-T Recommendation H.248.1 version 3 [i.5], clauses 7.2.8.1.11, 9, 11.2, 11.5, F.1, F.3.2, F3.5, F.3.11 or F.4.1.1. A primary MG is denoted by the facts that: 1) there is a single H.248 Control Association terminated in the MG; and that 2) there may be a secondary MG existing. The association between primary and secondary entity is given by support for redundancy on network level. primary Media Gateway Controller (MGC): according to "Primary MG" secondary Media Gateway (MG): according to "Primary MG" secondary Media Gateway Controller (MGC): according to "Primary MGC" NOTE: There can in general be a list of primary and secondary MGCs in each MG. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 10 |
a95505b1e252f195bf707ee85ccce821 | 183 025 | 3.2 Abbreviations | For the purposes of the present document, the following abbreviations apply: AGW Access GateWay DSP Digital Signal Processor FE Functional Entity IP Internet Protocol IS In Service MG Media Gateway MGC Media Gateway Controller MGW Media GateWay NGN Next Generation Network OOS Out-Of-Service PE Physical Entity RTP Real-time Transport Protocol SC ServiceChange (H.248) SCTP Stream Control Transmission Protocol SDO Standardization Development Organizations SNMP Simple Network Management Protocol TISPAN Telecommunications and Internet converged Services and Protocols for Advanced Networking TR Technical Report UDP User Datagram Protocol VMG Virtual Media Gateway |
a95505b1e252f195bf707ee85ccce821 | 183 025 | 4 Reference Architecture | Figure 1 illustrates the reference architecture assumed in the present document. MGC MG Management System H.248.1 Protocol Procedures Management Commands Management Commands Figure 1: Reference architecture The present document discusses the message primitives that may be passed over the Management Command interface and any related mappings into the H.248 control procedures and vice versa. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 11 |
a95505b1e252f195bf707ee85ccce821 | 183 025 | 5 H.248 Concepts And Logical Entities | |
a95505b1e252f195bf707ee85ccce821 | 183 025 | 5.1 H.248 Entities | H.248 commands and procedures are acting on H.248 logical entities. These are the different types: • Context: This is the entity that associates terminations together in a call or session. See also clause 6.1 of [i.5]. • NULL Context: This is a special Context which contains all Physical Terminations that are not associated with any other Termination. However, commands may still be initiated to and from these terminations. See also clause 6.1 of [i.5]. • Root Termination: This defines the MGW as an individual entity as a whole. See also clause 6.2.5 of [i.5]. • Physical Termination: This is an entity which has fixed physical characteristics (e.g. an analogue line) and requires pre-configuration via the management system prior to use within H.248 protocol. For such terminations, the MGC and MG are pre-provisioned to have a common view of the existing physical terminations. See also clause 6.2 of [i.5]. • Ephemeral Termination: This is a logical entity representing a dynamically created termination within the MGW (e.g. IP/RTP). No pre-configured characteristics are required for this type of entity, although in some profiles the MGC may have a dependency on the MG via the termination naming principles. See also clause 6.2 of [i.5]. Terminations may be individually addressed or as group (except Root Termination). Group addressing is performed via H.248 wildcarding. |
a95505b1e252f195bf707ee85ccce821 | 183 025 | 5.2 H.248 Non-Call Related Commands | The H.248.1 commands relevant to the present document are: • AuditValue: This command enables a MGC to request the supported packages and current state of properties, events, signals and statistics of terminations. For further details, see also clause 7.2.5 of [i.5]. • AuditCapability: This command enables a MGC to request all supported values for termination properties, events and signals allowed by the Media Gateway (i.e. the ROOT Termination). This command is not used in any of the TISPAN profiles and is thus considered to be out of scope in the present document. For further details, see also clause 7.2.6 of [i.5]. • ServiceChange: This command enables a MG to notify the MGC that a termination or group of terminations is about to be taken out of service or has just been returned to service. It also used by the MG to announce its availability to a MGC (registration), and to notify the MGC of impending or completed restart of the MG. The MGC may announce a handover to the MG by sending it a ServiceChange command. The MGC may also use ServiceChange to instruct the MG to take a termination or group of terminations in or out of service. For further details, see also clause 7.2.8 of [i.5]. • Notify: This command enables a MG to notify the MGC of any event occurring in the MG (that has been requested by the MGC). The Notify command is applicable to both call and non-call related procedures. Only the latter is in scope of the present document. For further details, see also clause 7.2.7 of [i.5]. ETSI ETSI TS 183 025 V2.5.1 (2009-04) 12 |
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