ETSI TS 129 162 V9.3.0 (2010-01)

Digital cellular telecommunications system (Phase 2+); Universal Mobile Telecommunications System (UMTS); LTE; Interworking between the IM CN subsystem and IP networks (3GPP TS 29.162 version 9.3.0 Release 9)

RTS/TSGC-0329162v930

General Information

• Status: Published
• Publication Date: 20-Jan-2010
• Technical Committee: 3GPP CT 3 - Interworking with external networks (formely CN3)
• Current Stage: 12 - Completion
• Due Date: 05-Jan-2010
• Completion Date: 21-Jan-2010

Standards Content (Sample)

ETSI TS 129 162 V9.3.0 (2010-01)
Technical Specification


Digital cellular telecommunications system (Phase 2+);
Universal Mobile Telecommunications System (UMTS);
LTE;
Interworking between the IM CN subsystem and IP networks
(3GPP TS 29.162 version 9.3.0 Release 9)

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3GPP TS 29.162 version 9.3.0 Release 9 1 ETSI TS 129 162 V9.3.0 (2010-01)



Reference
RTS/TSGC-0329162v930
Keywords
GSM, LTE, UMTS
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ETSI

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3GPP TS 29.162 version 9.3.0 Release 9 2 ETSI TS 129 162 V9.3.0 (2010-01)
Intellectual Property Rights
IPRs essential or potentially essential to the present document 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
server (http://webapp.etsi.org/IPR/home.asp).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
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, UMTS identities or
GSM identities. These should be interpreted as being references to the corresponding ETSI deliverables.
The cross reference between GSM, UMTS, 3GPP and ETSI identities can be found under
http://webapp.etsi.org/key/queryform.asp.
ETSI

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3GPP TS 29.162 version 9.3.0 Release 9 3 ETSI TS 129 162 V9.3.0 (2010-01)
Contents
Intellectual Property Rights . 2
Foreword . 2
Foreword . 5
1 Scope . 6
2 References . 6
3 Definitions, symbols and abbreviations . 7
3.1 Definitions . 7
3.2 Symbols . 7
3.3 Abbreviations . 8
4 General . 8
4.1 General interworking overview . 8
4.2 Interworking scenarios . 9
4.2.1 UE with 3GPP SIP profile capability connecting to an external SIP device. 9
5 Network characteristics . 9
5.1 Key characteristics of IP Multimedia Networks . 9
5.2 Key characteristics of UMTS IM CN Subsystem . 9
6 Interworking Reference Model for control plane interworking and user plane interworking . 9
6.1 Interworking Functional Entities . 11
6.1.1 S-CSCF . 11
6.1.2 IMS-ALG . 11
6.1.3 TrGW . 11
7 Control plane interworking . 11
7.1 SIP with 3GPP Profile to Standard SIP Interworking . 11
7.2 Additional interworking of protocol associated with supplementary services . 11
7.2.1 General . 11
7.2.2 Terminating Identification Presentation (TIP) and Terminating Presentation Restriction (TIR) . 11
7.2.3 Common Basic Communication . 12
8 User Plane Interworking . 12
8.1 Overview . 12
8.2 VOID . 12
8.3 VOID . 12
9 IMS-ALG and TrGW functionality for NAPT and IP Version Interworking . 12
9.1 Control plane interworking. 12
9.1.1 Session Set-up . 12
9.1.1.0 General . 12
9.1.1.1 Receipt of the first SDP offer . 12
9.1.1.2 Receipt of the first SDP answer . 13
9.1.2 Void . 13
9.1.3 Change of connection information . 13
9.1.4 Interworking of SIP messages . 13
9.2 User plane transport. 14
9.2.1 Payload transport . 14
9.2.2 IP header interworking . 14
9.2.2.1 IPv4 to IPv6 . 14
9.2.2.2 Abnormal cases . 15
9.2.2.3 IPv6 to IPv4 . 16
9.2.2.4 Abnormal cases . 17
9.2.3 Fragmentation . 17
9.2.4 Abnormal cases . 18
10 IBCF – TrGW Interactions . 18
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3GPP TS 29.162 version 9.3.0 Release 9 4 ETSI TS 129 162 V9.3.0 (2010-01)
10.1 Overview . 18
10.1.1 General . 18
10.1.2 Network model . 18
Example Call Flow . 18
10.1.3.1 Basic Procedures . 18
10.1.3.1.1 Call Establishment . 18
10.1.3.1.2 Call Release . 20
10.2.0 Introduction. 21
10.2 Main Functions supported at the Ix Interface . 21
10.2.1 IP Address and Port Conversion . 21
10.2.2 Gate Management . 21
10.2.3 Handling of RTCP Streams . 21
10.2.4 IP Realm/Domain Indication . 22
10.2.5 Media Control . 22
10.2.6 Media Inactivity Detection . 29
10.2.7 QoS Packet Marking . 29
10.2.8 Hanging Termination Detection . 29
10.2.9 Traffic Policing . 29
10.3 VOID . 29
10.4 Procedures . 29
10.4.1 Call related Procedures . 29
10.4.1.1 Reserve TrGW Connection Point . 29
10.4.1.2 Configure TrGW Connection Point . 31
10.4.1.3 Reserve and Configure TrGW Connection Point . 34
10.4.1.4 Release TrGW Termination . 37
10.4.1.5 IP Bearer Released . 37
10.4.1.6 Media Inactivity Detection . 38
10.4.1.7 Termination heartbeat indication . 38
10.4.2 Non Call related Procedures . 38
Annex A (informative): Codecs used for conversational services. 40
Annex B (informative): Change history . 41
History . 42

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3GPP TS 29.162 version 9.3.0 Release 9 5 ETSI TS 129 162 V9.3.0 (2010-01)
Foreword
rd
This Technical Specification has been produced by the 3 Generation Partnership Project (3GPP).
The contents of the present document are subject to continuing work within the 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 information;
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 been incorporated in the document.
ETSI

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3GPP TS 29.162 version 9.3.0 Release 9 6 ETSI TS 129 162 V9.3.0 (2010-01)
1 Scope
The IM CN subsystem interworks with the external IP networks through the Mb reference point.
This document details the interworking between the IM CN subsystem and external IP networks for IM service support.
It addresses the issues of control plane interworking and, user plane interworking for specific interworking use cases.
Clause 10 describes the IMS-Ix interface requirements in the form of Use Cases which require H.248 protocol
procedures. Subclause 10.4 then details the additional Information Elements required to perform the specific
procedures.
The IP version Interworking, between IP version 4 RFC 791 [9] and IP version 6 RFC 2460 [10] detailed in terms of the
processes and protocol mappings required in order to support both mobile originated and terminated calls.
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 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 document.
[1] 3GPP TS 24.229: "Internet Protocol (IP) multimedia call control protocol based on Session
Initiation Protocol (SIP) and Session Description Protocol (SDP); Stage 3".
[2] IETF RFC 3261: "SIP: Session Initiation Protocol".
[3] 3GPP TS 23.221: "Architectural requirements".
[4] 3GPP TS 29.061: "Interworking between the Public Land Mobile Network (PLMN) supporting
packet based services and Packet Data Networks (PDN)".
[5] 3GPP TS 23.002: "Network architecture".
[6] 3GPP TS 26.235: "Packet switched conversational multimedia applications; Default codecs".
[7] 3GPP TR 21.905: "Vocabulary for 3GPP Specifications".
[8] 3GPP TS 23.228: "IP Multimedia Subsystem (IMS); Stage 2".
[9] IETF RFC 791: "Internet Protocol".
[10] IETF RFC 2460: "Internet Protocol, Version 6 (IPv6) Specification".
[11] IETF RFC 2766: "Network Address Translation - Protocol Translation (NAT-PT)".
[12] IETF RFC 2663: "IP Network Address Translator (NAT) Terminology and Considerations".
[13] 3GPP TR 29.962 version 6.1.0: "Signalling interworking between the 3GPP profile of the Session
Initiation Protocol (SIP) and non-3GPP SIP usage".
[14] ITU-T Recommendation H.263: "Video coding for low bit rate communication".
[15] ITU-T Recommendation G.723.1: "Dual rate speech coder for multimedia communications
transmitting at 5.3 and 6.3 kbit/s".
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3GPP TS 29.162 version 9.3.0 Release 9 7 ETSI TS 129 162 V9.3.0 (2010-01)
[16] ITU-T Recommendation G.729: "Coding of speech at 8 kbit/s using conjugate-structure algebraic-
code-excited linear-prediction (CS-ACELP)".
[17] ITU-T Recommendation G.711: "Pulse code modulation (PCM) of voice frequencies".
[18] IETF RFC 792: "Internet Control Message Protocol".
[19] IETF RFC 2463: "Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version
6".
[20] IETF RFC 2765: 'Stateless IP/ICMP Translation Algorithm (SITT)".
[21] 3GPP TS 24.608: "Terminating Identification Presentation (TIP) and Terminating Identification
Restriction (TIR) using IP Multimedia (IM)Core Network (CN) subsystem; Protocol specification'.
[22] IETF RFC 3323: "A Privacy Mechanism for the Session Initiation Protocol (SIP)".
[23] IETF RFC 3325: "Private Extensions to the Session Initiation Protocol (SIP) for Network Asserted
Identity within Trusted Networks".
[24] 3GPP TS 24.628: "Protocols for Advanced Networking (TISPAN); Common Basic
Communication procedures; Protocol specification".
[25] 3GPP TS 29.238: "Interconnection Border Control Functions – Transition Gateway; H.248 Profile;
Stage 3"
[26] ITU-T Recommendation H.248.1 (05): "Gateway Control Protocol: Version 3"
[27] Void
[28] 3GPP TS 23.205: "Bearer-independent circuit-switched core network; Stage 2".
[29] 3GPP TS 29.235: "Interworking between SIP-I based circuit-switched core network and other
networks".
[30] IETF RFC 3550: "RTP: A Transport Protocol for Real-Time Applications".
[31] IETF RFC 2474: "Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6
Headers"


3 Definitions, symbols and abbreviations
3.1 Definitions
For the purposes of the present document, the terms and definitions given in 3GPP TR 21.905 [7] and the following
apply:
IM CN subsystem: (IP Multimedia CN subsystem) comprises of all CN elements for the provision of IP multimedia
applications over IP multimedia sessions
IP multimedia session: set of multimedia senders and receivers and the data streams flowing from senders to receivers
IP multimedia sessions are supported by the IP multimedia CN Subsystem and are enabled by IP connectivity bearers
(e.g. GPRS as a bearer). A user may invoke concurrent IP multimedia sessions.
3.2 Symbols
Void.
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3GPP TS 29.162 version 9.3.0 Release 9 8 ETSI TS 129 162 V9.3.0 (2010-01)
3.3 Abbreviations
For the purposes of the present document, the abbreviations given in 3GPP TR 21.905 [7] and the following apply: An
abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in
3GPP TR 21.905 [7].
BGCF Breakout Gateway Control Function
IBCF Interconnect Border Control Function
I-CSCF Interrogating CSCF
IMS-ALG IMS - Application Level Gateway
ITU-T International Telecommunication Union – Telecommunication Standardization Sector
MRFP Multimedia Resource Function Processor
NAT/NAPT Network Address Translation / Network Address and Port Translation
NA (P) T-PT Network Address (and Port) Translation - Protocol Translation
P-CSCF Proxy CSCF
RTCP Real Time Control Protocol
SCTP Stream Control Transmission Protocol
SIP UA SIP User Agent
SIP Session Initiation Protocol
THIG Topology Hiding Internetwork Gateway
TrGW Translation GateWay
WAN Wide Area Network
4 General
4.1 General interworking overview
The IM CN Subsystem interworks with SIP RFC 3261 [2] based IP Multimedia networks. These IP Multimedia
networks include:
- SIP User Agents (UAs);
- SIP Servers.
As such, the IM CN Subsystem has to be able to interwork to all of these above functional entities in the IP multimedia
network, as there is a possibility that they all may be involved in an IM session. The general interworking model is
shown in figure 1. The SIP based Multimedia networks may use IP version 4 RFC 791 [9] or IP version 6
RFC 2460 [10].


S-CSCF
I-CSCF
BGCF
Mx
SIP Proxy
P-CSCF
Mx
Mx
IBCF
SIP UA
IPv4 or IPv6
Ix
TrGW
Signalling
Bearer
IM CN subsystem network IP multimedia network

Figure 1: Interworking Model for IM CN Subsystem to IP Multimedia Network
The UE uses the CSCF in order to communicate with the external IP multimedia network entities.
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3GPP TS 29.162 version 9.3.0 Release 9 9 ETSI TS 129 162 V9.3.0 (2010-01)
If no IP version interworking or no NAT/NAPT between different realms is required, the CSCF can communicate with
SIP UAs in an external IP multimedia network directly.
If no IP version interworking or no NAT/NAPT between different realms is required, the CSCF can also communicate
with SIP proxies in an external IP multimedia network directly, which in turn can then communicate with SIP UAs.
To provide the IP version interworking or NAT/NAPT between different realms the functions of an IMS-ALG and a
TrGW may be inserted between the CSCF and external IP Multimedia Network by configuration. The IMS-ALG and
the TrGW may be implemented as a part of other physical entities in the IMS.
NOTE: Other methods to provide IP version interworking are for further study.
4.2 Interworking scenarios
3GPP specifications design the IM CN subsystem elements and interfaces to exclusively support IPv6.
3GPP TS 23.221 [3] details the interoperability scenarios that an UE may experience when interworking with an
external PDN. All of these IP transport layer interworking scenarios can apply to the application layer interworking
scenarios detailed in clause 4.2.1.
4.2.1 UE with 3GPP SIP profile capability connecting to an external SIP
device
The procedures used by an UE with 3GPP SIP profile to connect to an external SIP device, which may lack 3GPP SIP
profile capabilities, have been analysed in Release 6 within 3GPP TR 29.962 [13] and are specified in 3 GPP TS 24.229
[1].
5 Network characteristics
5.1 Key characteristics of IP Multimedia Networks
The Internet is a conglomeration of networks utilising a common set of protocols. IP protocols are defined in the
relevant IETF RFCs. The networks topologies may be based on LANs (e.g. Ethernet), Point-to-Point leased lines,
PSTN, ISDN, X.25 or WANs using switched technology (e.g. SMDS, ATM).
IP multimedia networks provide the ability for users to invoke IP multimedia applications in order to send and receive
(where applicable) voice and data communications. One protocol used to manage IP multimedia sessions is the Session
Initiation Protocol (SIP) (RFC 3261 [2]).
5.2 Key characteristics of UMTS IM CN Subsystem
The UMTS IM CN subsystem uses the SIP protocol to manage IP multimedia sessions, and uses IP as the transport
mechanism for both SIP session signalling and media transport.
The UMTS IM CN subsystem shall support interworking with existing fixed and mobile voice and IP data networks,
including PSTN, ISDN, Mobile and Internet.
6 Interworking Reference Model for control plane
interworking and user plane interworking
Figure 2 details the reference architecture required to support interworking between the IM CN subsystem and IP
networks for IM services. Figure 3 details the reference architecture required to support interworking between the IMS
and IP SIP networks supporting IP version 4.
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3GPP TS 29.162 version 9.3.0 Release 9 10 ETSI TS 129 162 V9.3.0 (2010-01)

CSCF
Mm
Multimedia IP
network
Mb

NOTE: Multimedia IP networks may be connected via the Mb interface to various network entities, such as an UE
(via an GTP Tunnel reaching to the GGSN), an MRFP, or an application server.

Figure 2: IM CN Subsystem to IP network interworking reference Architecture without IP version
interworking

Signalling
HSS
DNS
         Bearer
S-CSCF
I-CSCF BGCF
Mx Mx
P-CSCF
Mx
IBCF
Mx
IMS-ALG THIG
Ix
IP-CAN
TrGW
Other IMS/SIP
Border Control
UE
network
Functions
IMS network


Figure 3: Border Control Functions
Mm reference point: The call control protocol applied to the Mm interface between CSCF and external IP networks is
SIP, RFC 3261 [2], as detailed in 3GPP TS 24.229 [1]. SIP extension packages mandated by 3GPP are possibly not
supported.
Mb reference point: This interface is defined in 3GPP TS 23.002 [5] and is IP based. Further information is provided
in 3GPP TS 29.061 [4] and 3GPP TS 26.235 [6].
Mx reference point: The protocol applied at the Mx reference point is specified in 3GPP TS 24.229 [1].
Ix reference point: The protocol applied at the Ix reference point is specified in 3GPP TS 29.238 [25].
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3GPP TS 29.162 version 9.3.0 Release 9 11 ETSI TS 129 162 V9.3.0 (2010-01)
6.1 Interworking Functional Entities
6.1.1 S-CSCF
This entity provides control plane functionality to connect
...