ETSI TS 123 334 V13.10.0 (2020-01)

ETSI TS 123 334 V13.10.0 (2020-01)






TECHNICAL SPECIFICATION
Digital cellular telecommunications system (Phase 2+) (GSM);
Universal Mobile Telecommunications System (UMTS);
LTE;
IP Multimedia Subsystem (IMS)
Application Level Gateway (IMS-ALG) -
IMS Access Gateway (IMS-AGW) interface:
Procedures descriptions
(3GPP TS 23.334 version 13.10.0 Release 13)

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3GPP TS 23.334 version 13.10.0 Release 13 1 ETSI TS 123 334 V13.10.0 (2020-01)



Reference
RTS/TSGC-0423334vda0
Keywords
GSM,LTE,UMTS
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DECT™, PLUGTESTS™, UMTS™ and the ETSI logo are trademarks of ETSI registered for the benefit of its Members.

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®
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3GPP TS 23.334 version 13.10.0 Release 13 2 ETSI TS 123 334 V13.10.0 (2020-01)
Intellectual 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, 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 available on the ETSI Web
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Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
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Legal Notice
This Technical Specification (TS) has been produced by ETSI 3rd Generation Partnership Project (3GPP).
The present document may refer to technical specifications or reports using their 3GPP identities. These shall be
interpreted as being references to the corresponding ETSI deliverables.
The cross reference between 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 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

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3GPP TS 23.334 version 13.10.0 Release 13 3 ETSI TS 123 334 V13.10.0 (2020-01)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 8
1 Scope . 9
2 References . 9
3 Definitions, symbols and abbreviations . 13
3.1 Definitions . 13
3.2 Symbols . 13
3.3 Abbreviations . 14
4 Architecture . 14
4.1 Reference architecture . 14
4.2 NAT Function . 16
4.3 ATCF/ATGW Function . 17
4.4 eP-CSCF/eIMS-AGW Function . 17
5 Functional Requirements . 18
5.1 General . 18
5.2 Gate Control & Local NAT . 18
5.3 IP realm indication and availability . 18
5.4 Remote NAT traversal support . 19
5.5 Remote Source Address/Port Filtering . 19
5.6 Traffic Policing . 19
5.7 Hanging Termination Detection . 19
5.8 QoS Packet Marking . 20
5.9 Handling of RTCP streams . 20
5.10 Media Inactivity Detection . 21
5.11 IMS Media Plane Security . 21
5.11.1 General . 21
5.11.2 End-to-access-edge Security . 22
5.11.2.1 End-to-access-edge security for RTP based media using SDES . 22
5.11.2.2 End-to-access-edge security for TCP based media using TLS . 23
5.11.2.2.1 General . 23
5.11.2.2.2 e2ae security for session based messaging (MSRP) . 24
5.11.2.2.3 e2ae security for conferencing (BFCP) . 25
5.11.2.3 End-to-access-edge security for UDP based media using DTLS . 25
5.11.2.3.1 General . 25
5.11.2.3.2 e2ae security for T.38 fax over UDP/UDPTL transport . 25
5.11.2.4 End-to-access-edge security for RTP based media using DTLS-SRTP . 26
5.11.2.5 End-to-access-edge security for RTP based voice and video media using DTLS-SRTP over TCP. 27
5.11.2.6 End-to-access-edge security for WebRTC data channels using UDP/DTLS/SCTP transport . 28
5.11.3 End-to-end Security . 28
5.11.3.1 End-to-end security for RTP based media . 28
5.11.3.2 End-to-end security for TCP-based media using TLS . 28
5.12 Explicit Congestion Notification support . 28
5.12.1 General . 28
5.12.2 Incoming SDP offer with ECN . 29
5.12.3 Incoming SDP offer without ECN . 29
5.12.4 Detection of ECN failures by IMS-AGW . 29
5.13 Transcoding . 29
5.13.1 General . 29
5.13.2 Handling of common codec parameters. 30
5.13.3 Handling of the EVS speech codec . 31
5.13.4 Handling of the OPUS speech and audio codec for WebRTC . 48
ETSI

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3GPP TS 23.334 version 13.10.0 Release 13 4 ETSI TS 123 334 V13.10.0 (2020-01)
5.14 Multimedia Priority Service (MPS) Support . 51
5.15 Coordination of Video Orientation . 52
5.16 Generic image attributes . 53
5.17 TCP bearer connection control . 53
5.17.1 Stateless TCP handling . 53
5.17.2 State-aware TCP handling . 54
5.17.2.1 General . 54
5.17.2.2 State-aware TCP handling without support of modifying the TCP setup direction . 54
5.17.2.3 State-aware TCP handling with support of modifying the TCP setup direction . 55
5.18 Interactive Connectivity Establishment (ICE) . 57
5.18.1 General . 57
5.18.2 ICE lite . 57
5.18.3 Full ICE . 59
5.18.4 STUN consent freshness for WebRTC . 61
5.19 MSRP handling . 61
5.19.1 General . 61
5.19.2 IMS-ALG procedures to support IETF RFC 6714 with application agnostic MSRP handling by the
IMS-AGW . 62
5.19.3 IMS-ALG procedures to support IETF draft-ietf-simple-msrp-sessmatch with application agnostic
MSRP handling by the IMS-AGW . 62
5.19.4 IMS-ALG procedures for application aware MSRP interworking by the IMS-AGW . 63
5.19.5 Application-aware MSRP interworking at the IMS-AGW . 63
5.19.6 MSRP data channels . 63
5.20 Web Real-Time Communication (WebRTC) . 64
5.20.1 General . 64
5.20.2 WebRTC data channel . 65
5.20.2.1 General . 65
5.20.2.2 Data Channel Establishment . 65
5.20.2.3 Data Channel Release . 70
5.20.2.3.1 General . 70
5.20.2.3.2 Release of one WebRTC data channel . 71
5.20.2.3.3 Release of all or last active WebRTC data channels within an SCTP Association . 72
5.20.3 Media Plane Optimization . 72
5.20.3.1 General . 72
5.20.3.2 WIC originating call . 73
5.20.3.3 WIC terminating call . 73
5.21 Alternate Connection (ALTC) Addresses Management . 74
5.21.1 General . 74
5.22 Video Region-of-Interest (ROI) . 74
5.22.1 General . 74
5.22.2 "Far End Camera Control" mode . 75
5.22.3 "Predefined ROI" mode . 75
5.22.4 "Arbitrary ROI" mode. 76
5.23 SDP Capability Negotiation (SDPCapNeg) . 77
6 IMS-ALG to IMS-AGW Procedures . 77
6.1 Non-Call Related Procedures . 77
6.1.1 General . 77
6.1.2 IMS-AGW Unavailable . 78
6.1.3 IMS-AGW Available . 78
6.1.4 IMS-AGW Recovery . 79
6.1.5 IMS-ALG Recovery . 80
6.1.5.1 General . 80
6.1.5.2 IMS-ALG Restoration . 80
6.1.6 IMS-AGW Re-register . 80
6.1.7 IMS-AGW Re-registration Ordered by IMS-ALG . 81
6.1.8 Audit of IMS-AGW . 81
6.1.8.1 Audit of Value . 81
6.1.8.2 Audit of Capability . 82
6.1.9 IMS-AGW Capability Change . 82
6.1.10 IMS-ALG Out of service . 82
6.1.11 IMS-AGW Resource Congestion Handling - Activate . 83
ETSI

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3GPP TS 23.334 version 13.10.0 Release 13 5 ETSI TS 123 334 V13.10.0 (2020-01)
6.1.12 MGW Resource Congestion Handling -Indication . 83
6.1.13 Control association monitoring . 83
6.1.14 Realm Availability Monitoring . 84
6.1.15 Failure of IP Port, Interface or Group of Interfaces . 85
6.2 Call Related Procedures . 85
6.2.1 Gate Control & Local NA(P)T procedure . 85
6.2.2 IP realm indication procedure . 88
6.2.3 Remote NA(P)T traversal support procedure . 88
6.2.4 Remote Source Address/Port Filtering . 88
6.2.5 Traffic Policing . 89
6.2.6 Hanging Termination Detection . 89
6.2.7 QoS Packet Marking . 90
6.2.8 Media Inactivity Detection . 90
6.2.9 Handling of RTCP streams . 91
6.2.10 IMS end-to-access-edge Media Plane Security. 91
6.2.10.1 General . 91
6.2.10.2 End-to-access-edge security for RTP based media using SDES . 91
6.2.10.3 End-to-access-edge security for TCP-based media using TLS . 91
6.2.10.3.1 End-to-access-edge security for session based messaging (MSRP) . 91
6.2.10.3.1.1 IMS UE originating procedures for e2ae . 91
6.2.10.3.1.1.1 Incoming TCP bearer establishment triggers an outgoing TCP bearer establishment . 91
6.2.10.3.1.1.2 IMS-ALG requests sending an outgoing TCP bearer establishment . 94
6.2.10.3.1.2 IMS UE terminating procedures for e2ae . 96
6.2.10.3.1.2.1 Incoming TCP bearer establishment triggers an outgoing TCP bearer establishment . 96
6.2.10.3.1.2.2 IMS-ALG requests sending an outgoing TCP bearer establishment . 99
6.2.10.3.2 End-to-access-edge security for conferencing (BFCP) . 101
6.2.10.3.2.1 IMS UE originating procedures for e2ae . 101
6.2.10.3.2.1.1 Incoming TCP bearer establishment triggers an outgoing TCP bearer establishment . 101
6.2.10.3.2.2 IMS UE terminating procedures for e2ae . 104
6.2.10.3.2.2.1 Incoming TCP bearer establishment triggers an outgoing TCP bearer establishment . 104
6.2.10.4 End-to-access-edge security for UDP based media using DTLS . 107
6.2.10.4.1 General . 107
6.2.10.4.2 Session establishment from IMS access network for T.38 fax using "UDP/TLS/UDPTL" . 107
6.2.10.4.3 Session establishment towards IMS access network for T.38 fax using "UDP/TLS/UDPTL" . 110
6.2.10.4.4 IMS-AGW procedure for e2ae security of T.38 fax using "UDP/TLS/UDPTL" . 112
6.2.10.4.5 DTLS session establishment failure indication . 112
6.2.10.5 End-to-access-edge security for RTP based media using DTLS-SRTP . 113
6.2.10.6 End-to-access-edge security for WebRTC data channels using SCTP-over-DTLS transport . 117
6.2.10.6.1 General . 117
6.2.10.6.2 Call flow for data channel establishment from WIC towards IMS access network and MSRP
session establishment . 117
6.2.10A IMS end-to-end Media Plane Security . 120
6.2.10A.1 End-to-end security for RTP based media using SDES . 120
6.2.10A.2 End-to-end security for TCP-based media using TLS . 120
6.2.11 Change Through-Connection . 120
6.2.12 Emergency Calls . 120
6.2.13 Explicit Congestion Notification support . 120
6.2.13.1 General . 120
6.2.13.2 ECN Active Indicated (ECN transparent) . 120
6.2.13.3 ECN support requested (ECN endpoint) .
...