1、 ETSI TS 129 079 V15.0.0 (2018-07) Digital cellular telecommunications system (Phase 2+) (GSM); Universal Mobile Telecommunications System (UMTS); LTE; Optimal media routeing within the IP Multimedia Subsystem (IMS); Stage 3 (3GPP TS 29.079 version 15.0.0 Release 15) TECHNICAL SPECIFICATION ETSI ETS
2、I TS 129 079 V15.0.0 (2018-07)13GPP TS 29.079 version 15.0.0 Release 15Reference RTS/TSGC-0329079vf00 Keywords GSM,LTE,UMTS ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16 Siret N 348 623 562 00017 - NAF 742 C Association but non luc
3、ratif enregistre la Sous-Prfecture de Grasse (06) N 7803/88 Important notice The present document can be downloaded from: http:/www.etsi.org/standards-search The present document may be made available in electronic versions and/or in print. The content of any electronic and/or print versions of the
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9、by the GSM Association. ETSI ETSI TS 129 079 V15.0.0 (2018-07)23GPP TS 29.079 version 15.0.0 Release 15Intellectual Property Rights Essential patents IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The information pertaining to these essential IPRs,
10、if any, is publicly available for ETSI members and non-members, and can be found in ETSI SR 000 314: “Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect of ETSI standards“, which is available from the ETSI Secretariat. Latest updates are availa
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13、 no right to use or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks. Foreword This Technical Specification (TS) has been produced by ETSI 3
14、rd Generation Partnership Project (3GPP). The present document may refer to technical specifications or reports using their 3GPP identities, UMTS identities or GSM identities. These should be interpreted as being references to the corresponding ETSI deliverables. The cross reference between GSM, UMT
15、S, 3GPP and ETSI identities can be found under http:/webapp.etsi.org/key/queryform.asp. Modal verbs terminology In the present document “shall“, “shall not“, “should“, “should not“, “may“, “need not“, “will“, “will not“, “can“ and “cannot“ are to be interpreted as described in clause 3.2 of the ETSI
16、 Drafting Rules (Verbal forms for the expression of provisions). “must“ and “must not“ are NOT allowed in ETSI deliverables except when used in direct citation. ETSI ETSI TS 129 079 V15.0.0 (2018-07)33GPP TS 29.079 version 15.0.0 Release 15Contents Intellectual Property Rights 2g3Foreword . 2g3Modal
17、 verbs terminology 2g3Foreword . 5g31 Scope 6g32 References 6g33 Definitions, symbols and abbreviations . 7g33.1 Definitions 7g33.2 Symbols 8g33.3 Abbreviations . 8g34 General . 8g35 Common SDP Procedures 9g35.1 General . 9g35.2 Encapsulation of previous SDP information 9g35.2.1 Media level informat
18、ion 9g35.2.2 Session level information 9g35.3 Determination of codec related SDP information associated to a previous realm instance 10g35.4 Modifying codec related information . 11g35.4.1 Modifying the format list 11g35.4.2 Modifying preferred configurations 11g35.5 Additional handling for SDP answ
19、er with actual configuration . 12g35.6 Procedures specific to OMR attributes . 12g35.6.1 General 12g35.6.2 instance-number 12g35.6.3 Session and media checksum calculation . 13g35.7 Roaming architecture for voice over IMS with local breakout. 13g35.8 II-NNI traversal scenario 13g36 IMS-ALG procedure
20、s . 13g36.1 IMS-ALG handling of initial SDP offer . 13g36.1.1 General 13g36.1.2 Validating the received SDP offer 13g36.1.3 Deciding whether to allocate a primary local MR and if any previous MR can be bypassed . 14g36.1.4 Bypassing previous MRs 15g36.1.5 Bypassing no previous MRs . 16g36.1.6 Alloca
21、ting a primary local MR . 16g36.1.7 Allocating no primary local MR . 16g36.1.8 Allocating secondary local MRs . 17g36.1.9 Forwarding SDP offer . 18g36.2 IMS-ALG handling of initial SDP answer . 18g36.2.1 General 18g36.2.2 IMS-ALG bypasses an allocated transcoding MR 18g36.2.3 IMS-ALG allocates a loc
22、al transcoding MR when performing proactive transcoding without resource reservation 19g36.2.4 IMS-ALG determines steps required to complete the handling of the SDP answer . 19g36.2.5 Receiving an unspecified connection address and a visited-realm instance . 20g36.2.6 Receiving an unspecified connec
23、tion address and a secondary-realm instance 20g36.2.7 Other handling when no primary local MR allocated . 21g36.2.8 Retaining a primary or secondary local MR . 21g36.2.9 Forwarding the SDP answer . 22g36.3 IMS-ALG OMR media resource operations 22g36.3.1 General 22g36.3.2 IMS-ALG operations 23g36.4 H
24、andling of connected IP realms . 23g3ETSI ETSI TS 129 079 V15.0.0 (2018-07)43GPP TS 29.079 version 15.0.0 Release 157 UA Procedures . 23g37.1 UA sending an initial SDP offer . 23g37.2 UA receiving an initial SDP offer 24g37.2.1 General 24g37.2.2 Validating the incoming SDP offer . 24g37.2.3 UA may c
25、hoose an alternate realm instance to bypass an upstream MR 24g37.3 UA receiving an initial SDP answer . 25g37.3.1 General 25g37.3.2 Receiving SDP answer with an unspecified connection address 25g37.3.3 Receiving SDP answer with a valid connection address. 25g37.4 UA OMR media resource operations . 2
26、5g37.4.1 General 25g37.4.2 UA operations . 25g37.5 Handling of connected IP realms . 26g38 Subsequent SDP offer/answer transactions 26g38.1 General . 26g38.2 IMS-ALG and UA subsequent SDP offer procedures 26g38.3 IMS-ALG and UA subsequent SDP answer procedures 27g38.4 Handling media resources during
27、 a subsequent SDP offer/answer transaction 27g3Annex A (informative): Signalling flows 28g3A.1 Scope of signalling flows . 28g3A.2 Introduction 28g3A.3 Media bypassing all IMS-ALGs . 29g3A.3.1 General . 29g3A.3.2 Message flow 29g3A.4 IMS-ALG allocates a local transcoding MR when performing proactive
28、 transcoding without resource reservation 41g3A.4.1 General . 41g3A.4.2 Message flow 41g3A.5 IMS-ALG bypasses an allocated transcoding MR . 60g3A.5.1 General . 60g3A.5.2 Message flow 61g3A.6 Loopback routeing via an intermediate network 74g3A.6.1 General . 74g3A.6.2 Message flow 75g3Annex B (informa
29、tive): Change history . 89g3History 90g3ETSI ETSI TS 129 079 V15.0.0 (2018-07)53GPP TS 29.079 version 15.0.0 Release 15Foreword This Technical Specification has been produced by the 3rdGeneration Partnership Project (3GPP). The contents of the present document are subject to continuing work within t
30、he TSG and may change following formal TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an identifying change of release date and an increase in version number as follows: Version x.y.z where: x the first digit: 1 presented to TSG for i
31、nformation; 2 presented to TSG for approval; 3 or greater indicates TSG approved document under change control. y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections, updates, etc. z the third digit is incremented when editorial only changes have be
32、en incorporated in the document. ETSI ETSI TS 129 079 V15.0.0 (2018-07)63GPP TS 29.079 version 15.0.0 Release 151 Scope The present document defines optional Optimal Media Routeing (OMR) procedures that can be applied by entities in the IP Multimedia Subsystem (IMS) that control media resources and
33、are capable of manipulating the Session Description Protocol (SDP) as defined by IETF RFC 4566 6. The OMR procedures in the present specification relate to the handling of OMR-specific SDP attributes that are documented in TS 24.229 4. The OMR procedures use SDP offer/answer related procedures in IE
34、TF RFC 3264 5 and in 3GPP TS 24.229 4 in a backward-compatible manner. The 3GPP network architecture, including the configuration and network entities of the IMS, is defined in 3GPP TS 23.002 2. The Stage 2 of the IMS is defined 3GPP TS 23.228 3. Annex Q of 3GPP TS 23.228 3 documents the architectur
35、e and call flows for OMR. The OMR procedures in this document are applicable to the following IMS entities that perform as an IMS-ALG or UA according to 3GPP TS 24.229 4 and that control media resources: - an IBCF acting as an IMS-ALG; - a P-CSCF acting as IMS-ALG; - an AS acting as B2BUA and adapti
36、ng IMS-ALG procedures to control an MRF; - an AS acting as B2BUA and adapting UA procedures to control an MRF; and - an MGCF acting as UA. NOTE 1: An AS acting as B2BUA to perform application functions such as conferencing or announcements will normally perform separate originating and terminating U
37、A procedures, treating the media resource as an endpoint. An AS acting as B2BUA offering transcoding options will typically follow IMS-ALG procedures. NOTE 2: The controlled media resource can be a TrGW, IMS-AGW, MRF, or a media function of the entity performing OMR. The OMR procedures are not appli
38、cable for an UE. 2 References The following documents contain provisions which, through reference in this text, constitute provisions of the present document. - References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific. - For a specific
39、reference, subsequent revisions do not apply. - For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present doc
40、ument. 1 3GPP TR 21.905: “Vocabulary for 3GPP Specifications“. 2 3GPP TS 23.002: “Network architecture“. 3 3GPP TS 23.228: “IP multimedia subsystem; Stage 2“. 4 3GPP TS 24.229: “IP multimedia call control protocol based on Session Initiation Protocol (SIP) and Session Description Protocol (SDP); Sta
41、ge 3“. 5 IETF RFC 3264: “An Offer/Answer Model with Session Description Protocol (SDP)“. 6 IETF RFC 4566: “SDP: Session Description Protocol“. ETSI ETSI TS 129 079 V15.0.0 (2018-07)73GPP TS 29.079 version 15.0.0 Release 157 IETF RFC 2617: “HTTP Authentication: Basic and Digest Access Authentication“
42、. 8 IETF RFC 3605: “Real Time Control Protocol (RTCP) attribute in Session Description Protocol (SDP)“. 9 3GPP TS 29.238: “Interconnection Border Control Functions (IBCF) Transition Gateway (TrGW) interface, Ix Interface; Stage 3“. 10 3GPP TS 29.334: “IMS Application Level Gateway (IMS-ALG) IMS Acce
43、ss Gateway (IMS-AGW); Iq Interface; Stage 3“. 11 IETF RFC 4240: “Basic Network Media Services with SIP“. 12 IETF RFC 3260: “Media Control Channel Framework“. 13 IETF RFC 6505: “A Mixer Control Package for the media Control Channel Framework“. 14 3GPP TS 29.332: “Media Gateway Control Function (MGCF)
44、 IM Media Gateway Mn Interface“. 15 3GPP TS 23.334: “IP Multimedia Subsystem (IMS) Application Level Gateway (IMS-ALG) IMS Access Gateway (IMS-AGW) interface: Procedures descriptions“. 16 3GPP TS 29.162: “Interworking between the IM CN subsystem and IP networks“. 17 3GPP TS 29.163: “Interworking bet
45、ween the IP Multimedia (IM) Core Network (CN) subsystem and Circuit Switched (CS) networks“. 18 IETF RFC 5552: “SIP Interface to VoiceXML Media Services“. 19 IETF RFC 4117: “Transcoding Services Invocation in the Session Initiation Protocol (SIP) Using Third Party Call Control (3pcc)“. 20 IETF RFC 5
46、939: “Session Description Protocol (SDP) Capability Negotiation“. 21 IETF RFC 2234: “Augmented BNF for Syntax Specification: ABNF“. 22 IETF RFC 7549: 3GPP SIP URI Inter Operator Traffic Leg parameter“. 3 Definitions, symbols and abbreviations 3.1 Definitions For the purposes of the present document,
47、 the terms and definitions given in TR 21.905 1, and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905 1. Codec: A media configuration for a media line in SDP that is specified by one or more formats in the format
48、list of the m-line, by one or more preferred configurations (pcfg) associated with the media line, or by a combination of both. Codec Change: Any modification to the media configurations for the media line in the format list or the list of preferred configurations. Codec List: Either the format list
49、 of the m-line, or a combination of all the preferred configurations and the format list for the media line. Connected IP realm: Compared to a reference IP realm, a connected IP realm is one identified with a different unique name where all IP endpoints in the two IP realms are mutually reachable (accessible) by means of IP routeing without address translation. Interconnection between the IP realms may be via direct link, via IP tunnel through other networks, via IP routeing through intermediate networks,
