SIST-TS TS 101 884 V1.1.1:2004

Telecommunications and Internet Protocol Harmonization Over Networks (TIPHON) Release 3; Technology Mapping; Implementation of TIPHON architecture using SIP

This work item will deliver a mapping of the reference points C1.C2.C3. SC1, R1, R2 and WI2003 to the SIP/SDP protocols.

Harmonizacija telekomunikacij in internetnega protokola prek omrežij (TIPHON), 3. izdaja - Tehnologija preslikave - Implementacija arhitekture TIPHON z uporabo SIP

General Information

• Status: Published
• Publication Date: 31-Mar-2004
• ICS: 33.020 - Telecommunications in general
• Technical Committee: SPN - Services and Protocols for Networks
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Apr-2004
• Due Date: 01-Apr-2004
• Completion Date: 01-Apr-2004
• Ref Project: ETSI TS 101 884 V1.1.1 (2002-09) - Telecommunications and Internet Protocol Harmonization Over Networks (TIPHON) Release 3; Technology Mapping; Implementation of TIPHON architecture using SIP

Standards Content (Sample)

SLOVENSKI STANDARD
01-april-2004
Harmonizacija telekomunikacij in internetnega protokola prek omrežij (TIPHON), 3.
izdaja - Tehnologija preslikave - Implementacija arhitekture TIPHON z uporabo SIP
Telecommunications and Internet Protocol Harmonization Over Networks (TIPHON)
Release 3; Technology Mapping; Implementation of TIPHON architecture using SIP
Ta slovenski standard je istoveten z: TS 101 884 Version 1.1.1
ICS:
33.020 Telekomunikacije na splošno Telecommunications in
general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

Technical Specification
Telecommunications and Internet Protocol
Harmonization Over Networks (TIPHON) Release 3;
Technology Mapping;
Implementation of TIPHON architecture using SIP

2 ETSI TS 101 884 V1.1.1 (2002-09)

Reference
DTS/TIPHON-03018
Keywords
architecture, IP, SIP, telephony, VoIP
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The copyright and the foregoing restriction extend to reproduction in all media.

© European Telecommunications Standards Institute 2002.
All rights reserved.
TM TM TM
DECT , PLUGTESTS and UMTS are Trade Marks of ETSI registered for the benefit of its Members.
TM
TIPHON and the TIPHON logo are Trade Marks currently being registered by ETSI for the benefit of its Members.
TM
3GPP is a Trade Mark of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners.
ETSI
3 ETSI TS 101 884 V1.1.1 (2002-09)
Contents
Intellectual Property Rights.5
Foreword.5
Introduction .5
1 Scope.8
2 References.8
3 Definitions and abbreviations.9
3.1 Definitions.9
3.2 Abbreviations.9
4 Implementation of TIPHON functional architecture using SIP .10
4.1 SIP functional architecture .10
5 Registration.12
5.1 Adding contact addresses .15
5.1.1 Procedures in the SIP terminal.15
5.1.1.1 Normal procedure.15
5.1.1.2 Exceptional procedures in terminals .16
5.1.2 Procedures in the SIP registrar and in the SIP proxy.16
5.1.2.1 Procedures at SIP registrar in home network .17
5.1.2.1.1 Normal procedures.17
5.1.2.1.2 Exceptional procedures.17
5.1.2.2 Procedures in the SIP proxy.17
5.1.2.2.1 Normal procedures.17
5.1.2.2.2 Exceptional procedures.18
5.2 Refreshing contact addresses.18
5.2.1 Procedures in the SIP terminal.19
5.2.2 Procedures in the SIP registrar.19
5.2.3 Procedures in the SIP proxy.19
5.3 Removing contact addresses.19
5.3.1 Procedures in SIP terminal .19
5.3.1.1 Normal procedure.19
5.3.1.2 Exceptional procedures.19
5.3.2 Procedures in the SIP registrar.19
5.3.2.1 Normal Procedure.19
5.3.2.2 Exceptional procedure.20
5.3.3 Procedures in the SIP proxy.20
5.3.3.1 Normal procedures.20
5.3.3.2 Exceptional procedures.20
6 Simple Call Application .21
6.1 General behaviour.21
6.1.1 Timers.21
6.1.1.1 Timer A.21
6.1.1.2 Timer B.21
6.1.1.3 Timer C.21
6.1.1.4 Timer D.22
6.1.2 100rel (early media).22
6.1.3 Resource Reservation at ICF .22
6.1.3.1 Normal procedure.22
6.1.3.2 Exceptional procedures.23
6.2 Procedures for Call Set-up at the calling party's SIP terminal.23
6.2.1 Call establishment.23
6.2.2 Call Clear Down .24
6.2.3 Exceptional procedures.24
6.3 Procedures in the Serving and intermediate network (calling party).24
ETSI
4 ETSI TS 101 884 V1.1.1 (2002-09)
6.3.1 Call establishment.24
6.3.2 Call clearing.25
6.3.3 Exceptional procedures.25
6.4 Procedures in the SIP proxy in the home network (Calling Party).25
6.4.1 Call establishment.25
6.4.2 Call Clearing.26
6.4.3 Exceptional procedures.26
6.5 Procedures at the SIP proxy in the Intermediate network .26
6.5.1 Call establishment.26
6.5.2 Call clearing.27
6.5.3 Exceptional procedures.27
6.6 Procedures at the SIP proxy in the home network (called party) .27
6.6.1 Call establishment.27
6.6.2 Call clearing.28
6.6.3 Exceptional procedures.28
6.7 Procedures in the Serving and intermediate network (called party) .28
6.7.1 Call establishment.28
6.7.2 Call clearing.29
6.7.3 Exceptional procedures.29
6.8 Procedures at the called party's SIP terminal.29
6.8.1 Call establishment.29
6.8.2 Call clearing.29
6.8.3 Exceptional procedures.30
6.9 Procedures at the SIP gateway: IP to SCN.30
6.9.1 Call establishment.30
6.9.2 Call clearing.31
6.9.3 Exceptional Procedures.31
6.10 Procedures for Call Set-up at SIP gateway: SCN to IP .31
6.10.1 Call establishment.31
6.10.2 Call clearing.32
6.10.3 Exceptional procedures.32
Annex A (normative): Mapping of TIPHON Registration Meta-protocol to SIP.34
A.1 Registration Messages Mapping .34
A.2 Detailed mapping of TIPHON Registration parameters to SIP.34
Annex B (normative): Mapping of SIP to TIPHON Call Control meta-protocol.37
Annex C (informative): Services Supported by SIP in TIPHON Release 3 .43
Annex D (normative): Minimum set of SIP Messages and Parameters required in TIPHON
R3 .44
Annex E (informative): Capabilities missing from SIP and SDP.46
Annex F (informative): SIP flows for scenarios 0 to 3 .47
F.1 Scenario 0.47
F.2 Scenario 1.48
F.3 Scenario 2.49
F.4 scenario 3.50
Annex G (informative): Bibliography.51
List of figures.52
List of tables .52
History .53

ETSI
5 ETSI TS 101 884 V1.1.1 (2002-09)
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 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 Project Telecommunications and Internet Protocol
Harmonization Over Networks (TIPHON).
Introduction
The SIP profile contained in the present document is derived from examination of:
• the capabilities required by TS 101 878 [6] for the support of TIPHON as identified in TR 101 300 [4];
• the TIPHON baseline architecture described in TS 101 314 [1]; and
• the primitives, parameters and procedures defined in TS 101 882 [7].
The documents listed above are compared and evaluated against the IETF protocols SIP [SIP], SDP [SDP] and DNS
[DNS].
The relationship between the TIPHON documents can be better seen in the figure 1.
ETSI
6 ETSI TS 101 884 V1.1.1 (2002-09)
TR 101 301
Release 3: Scope & Definition
TR 102 008
Definition of Terms
Transport Plane Service Capabilities
TR 101 311 TS 101 878
Architecture & Reference
TS 101 314
configurations
Implementer's
Protocol
TS 101 882 TS 101 315
guide
Framework
TS 101 883 TS 101 884 TS 101 885
H.323 profile SIP profile H.248 profile
TS 101 890 TS 101 889 TS 101 804 TS 102 027
-1, -2, -3 -1, -2 -1, -2, -3 -1, -2
SIP,
H.225 PICS,
H.245 PICS,
H248 PICS,
TSS&TPs,
TSS&TPs, TSS&TPs,
TSS&TPs
ATS & PIXIT
ATS & PIXIT
ATS & PIXIT
Figure 1: Relationship with other TIPHON Release 3 documents
• TR 101 311 [11] provides the requirements on the transport plane.
• TS 101 878 [6] defines service capabilities that are used in the TIPHON Release 3 for a simple call.
• TS 101 882 [7] provides the Protocol Framework based on the TIPHON Release 3 architecture to implement the
simple call service capabilities as defined in the present document.
• TS 101 315 [5] is an implementer's guide that shows how to use of the meta-protocol to realize the capabilities as
defined in TS 101 878 [6].
• TS 101 883 [12] provides the protocol mappings for the ITU-T H-323 profile.
• TS 101 884 (the present document) provides the protocol mappings for the SIP profile.
ETSI
7 ETSI TS 101 884 V1.1.1 (2002-09)
• TS 101 885 [13] provides the protocol mappings for the ITU-T H-248 profile.
• TS 101 314 [1] provides the architecture and reference configurations for TIPHON Release 3.
ETSI
8 ETSI TS 101 884 V1.1.1 (2002-09)
1 Scope
The present document describes how the SIP and SDP protocols can be used to implement TIPHON architecture, as
defined in [5], and the Context and Behaviour of Meta-Protocol, as defined in [7].
The scope of the present document is limited to the mapping of the following parts of Meta-Protocol to SIP:
• Registration Meta-Protocol;
• Call Control Meta-Protocol;
• Bearer Control Meta-Protocol.
The present document is applicable to equipment performing the roles of terminal, Registration server, proxy
Application Server, and gateway, and also to entities within the IP network that are necessary to support the TIPHON
Release 3.
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 and/or edition number or version number) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
• For a non-specific reference, the latest version applies.
[1] ETSI TS 101 314: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 3; Abstract Architecture and Reference Points Definition; Network
Architecture and Reference Points".
[2] IETF RFC 3261: "SIP: Session Initiation Protocol".
[3] IETF RFC 2327: "SDP: Session Description Protocol".
[4] ETSI TR 101 300: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON); Description of Technical Issues".
[5] ETSI TS 101 315: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 3; Functional entities, information flow and reference point definitions;
Guidelines for application of TIPHON functional architecture to inter-domain services".
[6] ETSI TS 101 878: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 3; Service Capability Definition; Service Capabilities for a simple call".
[7] ETSI TS 101 882: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 3; Protocol Framework Definition; General (meta-protocol)".
[8] IETF RFC 3262: "Reliability of Provisional Responses in Session Initiation Protocol (SIP)".
[9] ETSI TR 101 301: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 3; Release Definition; TIPHON Release 3 Definition".
[10] ETSI TR 102 008: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 3; Terms and Definitions".
[11] ETSI TR 101 311: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 3; Service Independent requirements definition; Transport Plane".
ETSI
9 ETSI TS 101 884 V1.1.1 (2002-09)
[12] ETSI TS 101 883: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 3; Technology Mapping; Implementation of TIPHON architecture using
H.323".
[13] ETSI TS 101 885: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 3; Technology Mapping; Technology Mapping of TIPHON reference point N
to H.248/MEGACO protocol".
[14] ETSI TS 101 890 (all parts): "Telecommunications and Internet Protocol Harmonization Over
Networks (TIPHON) Release 3; Technology Compliance Specifications; TIPHON profile for
ITU-T H.245".
[15] ETSI TS 101 889-1: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 3; Technology Compliance Specification; TIPHON profile for ITU-T H.248;
Part 1: Protocol Implementation Conformance Statement (PICS) proforma specification".
[16] ETSI TS 101 889-2: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON) Release 3; Technology Compliance Specification; TIPHON profile for ITU-T H.248;
Part 2: Test Suite Structure and Test Purposes (TSS&TP) specification".
[17] ETSI TS 101 804 (all parts): "Telecommunications and Internet Protocol Harmonization Over
Networks (TIPHON) Release 3; Technology compliance specifications; Part 1: Revision/Update
of H.225.0 Protocol Implementation Conformance Statement (PICS) proforma specification for
Terminal, Gatekeeper and Gateway".
[18] ETSI TS 102 027-1: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON); Technology Compliance Specification; Draft IETF SIP RFC2543bis-04; Part 1: Test
Suite Structure and Test Purposes (TSS&TP) specification".
[19] ETSI TR 101 877: "Telecommunications and Internet Protocol Harmonization Over Networks
(TIPHON); Requirements Definition Study; Scope and Requirements for a Simple call".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the terms and definitions given in TR 101 877 [19] and TS 101 878 [6] apply.
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
API Application Programming Interface
ASN.1 Abstract Syntax Notation One
B2BUA Back-to-Back User Agent
BC Bearer Control
CC Call Control
FE Functional Entity
FG Functional Grouping
GFG Gateway Functional Group
GoS Grade of Service
ICF Inter-Connect Function
IP Internet Protocol
IPTN IP Telephony Network
ISDN Integrated Services Digital Network
MC Media Control
MPMU Meta Protocol Message Unit
MSC Message Sequence Chart
NFG Network Functional Group
ETSI
10 ETSI TS 101 884 V1.1.1 (2002-09)
PCM Pulse Code Modulation
PDU Protocol Data Unit
RpoA Registration point of Attachment
PSTN Public Switched Telephone Network
QoS Quality of Service
SAP Service Access Point
SC Service Control
SCN Switched Circuit Networks
SDL Specification and Description Language
SpoA Service point of Attachment
SLA Service Level Agreement
SL Service Layer
TCC-SAP TIPHON Call Control SAP
TE Terminal Equipment
TFG Terminal Functional Group
TLL-SAP TIPHON Lower Layer SAP
TRL TIPHON Resource Location
TR-SAP TIPHON Registration SAP
TT-SAP TIPHON Transport SAP
UA User Agent
UAC User Agent Client
UAS User Agent Server
URI Uniform Resource Identifier
4 Implementation of TIPHON functional architecture
using SIP
The SIP technology includes two protocols of interest to TIPHON:
• SIP - As defined in SIP RFC [2] this is often used as a client/server based call control protocol.
• SDP - A Bearer Control protocol, as defined in IETF RFC 2327 [3].
SIP identifies a number of functional entities: SIP User Agents (UA), SIP registrar, SIP servers, SIP proxies and SIP
gateways. The present document describes the behaviour of, and the communication between these functional entities in
the context of TIPHON.
TS 101 314 [1] defines a number of reference points and Functional Entities (FE). These reference points and
Functional Entities need to be mapped to SIP based architecture before behaviours and message flows can be defined.
For this purpose, an introduction to the SIP Architecture is given below, along with its mapping to TIPHON functional
architecture.
4.1 SIP functional architecture
The SIP Architecture has the following functional elements, as defined in [2].
User Agent (UA): The user agent is the functional entity that may initiate or respond to a SIP request.
In a TIPHON compliant system, the SIP User Agent (UA) shall provide the functionality of the terminal functional
group. The terminal functional group performs the roles of the terminal registration functional group, originating
terminal functional group and the terminating terminal functional group. The reference points S1, SC1 and N1 are
regarded as internal to the TE. The UA may use the DNS server.
Back-to-Back User Agent (B2BUA): B2BUA is a logical entity that receives a request and processes it as a User
Agent Server (UAS). In order to determine how a request should be answered, it acts as a User Agent Client (UAC) and
generates requests. Unlike a proxy server (stateless), it maintains a dialogue state, and must participate in all requests
sent on the dialogues it has established. TIPHON recommends the use of a B2BUA, as network functional groupings
involved in providing a service.
ETSI
11 ETSI TS 101 884 V1.1.1 (2002-09)
SIP Server: A SIP server provides a service to SIP user agents and/or proxies and other servers. An example of such a
server can be a redirect server.
Proxy server: A proxy server acts as both the client and server: It receives a request from an entity, and initiates a
request on behalf of the requesting entity, hence acting as a server for the requesting entity.
• Registration server: The registration server processes registration requests; as a minimum this involves
updating the users contact list and responding to the originator of the request. Typically a registration server is
co-located with either the proxy or the redirect server, and may be adapted to perform location-based services.
• SIP gateway: A SIP gateway acts as an interworking medium between the PSTN and IP networks. It provides
an interworking between the SIP and other call control protocols, such as ISUP, as well as interworking between
the TDM and IP media flows.
Figure 2 shows how the SIP functional elements map onto the functional layers in the IP Telephony Application plane.

SIP
Redirect Registrar
Stateful Service  Service
Terminal
Server
Proxy SIP/PSTN
Gateway
User
Agent
Service
Service
Stateless
(note)
Function
Control
Control
Proxy
Call
Control
Bearer
Control
Media
Processing
Media
Function
Control
NOTE: Compound gateway.
Figure 2: The SIP example mapped onto the IP telephony application plane
The UA maps to Service, Service Control (SC), Call Control (CC), and Bearer Control (BC) layers.
The statefull proxy maps to the TIPHON service and call control layer.
The SIP PSTN gateway covers all TIPHON layers.
The redirect server works at TIPHON Service Control layer.
The registrar works at TIPHON Service and Service Control layer.
Figure 3 shows the SIP entities and how they map to the functional layers and the Functional Groups (FG) defined in
[1].
ETSI
12 ETSI TS 101 884 V1.1.1 (2002-09)
NFG
DNS
AAA
ENUM
IP Network services
S2, S3, A S3, A
S5 S5
TFG NFG GFG
SIP UA SIP
proxy
SIP
R1 R2
SIP
Registrar
Gateway
C1 C2 C2
S
SIP
C
Proxy
N
N3
M1/M2 Media
Gateway
M1 M2
NOTE: All entities in an IP network "normally" use the DNS service. In the context of the present document only
relations to the DNS with ENUM extensions are shown.

Figure 3: SIP Architecture mapped to the TIPHON Functional layers and functional groups
The SIP proxy, SIP server, SIP gateway and the SIP Registration Server shall provide the functionality required in the
Network Functional Group (NFG). Reference point S2, S3 and A are between the Network Functional Group and
S5
other IP Network services e.g. DNS. The Network Functional Group may play the roles of an originating Network
Functional Group, an intermediate Network Functional Group or a terminating Network Functional Group.
NOTE: The Network Functional Group may include Media Control Functional Entities, e.g. for giving
announcements, mixing media streams etc. This is, however, out of scope of the present document.
The present document describes the mapping of functional architecture [1], as well as the context, behaviour and
procedures [7] that the SIP and SDP protocols must adhere to, to be TIPHON compliant. In TIPHON Release 3, SIP is
mapped to reference points R1, R2, C1, C2, where R1 and R2 refer to the registration reference points, whereas C1 and
C2 refer to call & bearer control reference points. The R and C reference points will be dealt with separately in the
present document, because of the different nature of services they provide.
5 Registration
This clause applies to SIP terminals, SIP proxies and SIP registrars and describes how the SIP [2] shall be used in order
to implement the registration meta-protocol defined in the annex A of TS 101 882 [7].
SIP [2] defines how a user registers with a SIP registrar in one service provider's domain. The present document extends
this registration procedure to also include the registration of users via another service provider's domains.
NOTE 1: The intention of this clause is not repeat the SIP RFC [2] text, but to select options and to clarify relations
with TIPHON architecture in TS 101 314 [1], and the registration meta protocol in TS 101 882 [7].
Two registration scenarios shall be supported:
• The "user at home" scenario; and
• The "roaming user" scenario.
NOTE 2: For more details and examples of the two scenarios see TS 101 315 [5].
ETSI
Service
Control
Services
Layer
Layer
Call
l
Contro
Layer
Bearer
ont
C rol
Layer
Media
Control
Layer
13 ETSI TS 101 884 V1.1.1 (2002-09)
The registration meta-protocol defines three steps for a user to access a service application:
1) location of the Registration point of Attachment (RpoA);
2) registration; and
3) attachment to the service application.
The objective with the step 1 is to locate the Registration point of Attachment. This step may be implemented using
DHCP. This step is out of scope of the present document.
Step 2 is a "Single log-on" procedure where a user registers to one registrar and receives tickets for all service
applications available to the user. SIP does not support the "Single log-on" procedure at present, hence out of scope of
the present document.
Step 3 describes how users attach to (or detach from) a service application. In the context of the present document the
service application is the VoIP service application based on SIP. Therefore, the SIP registrant registers with a SIP
registrar providing both the registration and VoIP services.
Figure 4 shows how TS 101 882 [7] M-PDUs is mapped to corresponding SIP [2] methods.
SIP SIP
U_SpoAService Attach Request =
U_SpoAService Attach Response = 200
U_SpoAService Detach Request =
U_SpoAService Detach Response = 200

Figure 4: Mapping of TS 101 882 [7] M-PDUs to SIP [2] methods
Figure 5 shows the message flow for the "user at home" scenario where the SIP terminal registers directly to the SIP
registrar in the home network without involving intermediate networks. The information flows between the SIP
terminal and the SIP registrar in the home network flows on TIPHON reference point R1.
ETSI
14 ETSI TS 101 884 V1.1.1 (2002-09)
SIP
SIP REGISTRAR in
Terminal
the Home Network
REGISTER
401 UnAuthorized
REGISTER
200 OK (REGISTER)
Figure 5: "User at home" registration
The SIP terminal sends the REGISTER message to the SIP registrar in the home network. The SIP registrar in the home
network returns a '401 Unauthorized' response in order to authenticate the user. The '401 Unauthorized'
response includes a challenge. The SIP terminal sends (for the second time) the REGISTER message to the SIP registrar
in the home network. The REGISTER message now includes the response to the challenge. The SIP registrar in the
home network acknowledges the registration by means of the '200 OK' final response.
Figure 6 shows the message flow for the "Roaming user" scenario, where the SIP terminal registers with the SIP
registrar in the home network, via a SIP proxy in the serving network and a SIP proxy in the intermediate network. The
information flows between the SIP terminal and the SIP proxy in the serving network flows on TIPHON reference point
R1. The information flows between the SIP proxies in the serving network and in the intermediate network and the SIP
registrar in the home network flows on TIPHON reference point R2.
SIP SIP Proxy in the SIP Proxy in the SIP Registrar in the
Terminal SERVING Network Intermediate Network Home Network
REGISTER
REGISTER REGISTER
401 UnAuthorized
401 UnAuthorized
401 UnAuthorized
REGISTER
REGISTER
REGISTER
200 OK (REGISTER)
200 OK (REGISTER)
200 OK (REGISTER)
Figure 6: "Roaming user" registration
The SIP terminal sends the REGISTER message to the SIP proxy in the serving network. The SIP proxy forwards the
message to a SIP proxy in the intermediate network which forwards the REGISTER message to the SIP registrar in the
home network.
NOTE 3: The above behaviour assumes that a bilateral agreement exists between the serving network and the
intermediate network and between the intermediate network and the home network. The handling of
bilateral agreements and how they are stored is out of the scope of the present document.
ETSI
15 ETSI TS 101 884 V1.1.1 (2002-09)
The SIP registrar in the home network returns a "401 Unauthorized" response in order to authenticate the user.
The "401 Unauthorized" response includes a challenge.
The "401 Unauthorized" response is returned (via the SIP proxies in the intermediate network and the serving
network) to the SIP terminal.
The SIP terminal sends (for the second time) a REGISTER message towards the SIP registrar in the home network (via
the SIP proxy in the serving network and the intermediate network).
This REGISTER message now includes the response to the challenge.
The SIP registrar in the home network acknowledges the registration by means of the '200 OK'.
The following clause describes the behaviour in the SIP terminal, the SIP proxy in the serving network, the SIP proxy in
the intermediate network and the SIP registrar in the home network when a user attach to and detach from the VoIP
service application.
5.1 Adding contact addresses
The REGISTER message is used to register new contact addresses. The same message may (at the same time) be used
to refresh existing contact addresses and remove existing contacts. For simplicity this clause assumes that the
REGISTER message only includes contact addresses to be refreshed.
5.1.1 Procedures in the SIP terminal
This clause applies to all SIP terminals.
5.1.1.1 Normal procedure
The SIP terminal shall register with a SIP registrar as described in [2] clause 10 "Registrations" with the clarifications
below.
The user shall register one or more contact addresses where he is reachable. Registrations are additive i.e. the user may
add more contacts addresses to an already active registration.
The following procedures take place for the registration to be complete (see figures 5 and 6 for an overview of the
message flow).
The REGISTER message shall be coded as defined in SIP [2] clause 10.2 "Construction of the REGISTER request"
with the following clarifications:
• The 'TO" header field shall include the public identity of the user. The public identity shall be in the format of
a SIP-URL or a TEL-URL.
• The 'FROM" header field shall include the same public identity as in 'TO" header field.
rd
NOTE 1: The 'FROM" header field may (in the case of a 3 party registration) be different from the user identity
in the 'TO" header field ('TO" represents a user being registered; 'FROM" represents a user initiating
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registration). However, the TIPHON Release 3 does not support a 3 party initiated registration.
• The 'REQUEST-URI" in the format of the SIP URL, shall be the domain name of the SIP registrar in the home
network.
• The SIP terminal may include a suggestion for how long the registration shall be valid in either the 'EXPIRE"
header field or in the 'EXPIRE" parameter in the 'CONTACT" header field. In case the SIP terminal does not
include a value, the one hour shall be assumed; and
• at least one 'CONTACT" header field shall be included.
NOTE 2: If no 'CONTACT" header field is included in the REGISTER message the SIP registrar returns all active
"bindings" for the user identity in the 'TO" header field. A "binding" is a combination of a user identity
and one contact address.
ETSI
16 ETSI TS 101 884 V1.1.1 (2002-09)
The REGISTER message shall be sent to the SpoA. In the context of the present document the SpoA may be a SIP
proxy in a serving network or the SIP registrar in the home network.
The SIP terminal may obtain the address to the SpoA in one of the following ways:
• by means of a "Single log-on" procedure. Out of scope of the present document;
• by manual configuration in the SIP terminal; or
• by using the multicast procedure defined in [2] clause 10.2.5 "Discovering a registrar".
In the case the SpoA address is in the format of a URI (i.e. not an IP address) the SIP terminal shall use the DNS to
resolve the URI to an IP address each time a REGISTER message is sent (this is also true for retransmitted REGISTER
messages).
The SIP terminal shall supervise the reception of a response message to the REGISTER message.
On receipt of a '401 Unauthorized' response the SIP terminal shall provide credentials (see [2] clause 20.3
"Proxy to User Authentication") and retransmit the REGISTER message.
The retransmitted REGISTER message shall:
• be constructed as described earlier in this clause; and
• include the 'PROXY-AUTHORIZATION" where 'username' parameter is the User's private identity (i.e. the
private user identity of the user identity in the 'FROM" header field).
NOTE 3: The above authentication scheme only authenticates the user. In the case the SIP registrar should be
authenticated the clause 22.3.2.1 "Registration" is recommended.
On receipt of the '200 OK' final response the SIP terminal shall stop time supervision of the response to the
REGISTER message and start timers for refreshing the registrations according to the 'EXPIRE' header field or
according to the 'expire' parameter in the 'CONTACT" header field.
The SIP terminal shall store the IP address (received from DNS when resolving the SpoA address in an URI format)
used when sending the REGISTER message. The SIP terminal shall use this IP address for future request towards the
home network (with the exception of REGISTER request messages).
See annex A for details on REGISTER message and its contents.
5.1.1.2 Exceptional procedures in terminals
Upon receipt of 3XX, 4XX (with the exception of the '401 Unauthorized" or 5XX responses to th
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