SIST-TS ETSI/TS 102 141 V1.1.1:2005

• Abstract:

  To endorse and constrain where relevant the SIGTRAN (IETF) RFC of M2UA

• Status: Published
• Publication Date: 31-Dec-2004
• ICS: 33.040.01 - Telecommunication systems in general
• Technical Committee: SPN - Services and Protocols for Networks
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Jan-2005
• Due Date: 01-Jan-2005
• Completion Date: 01-Jan-2005
• Ref Project: ETSI TS 102 141 V1.1.1 (2003-05) - Services and Protocols for Advanced Networks (SPAN); MTP/SCCP/SSCOP and SIGTRAN (Transport of SS7 over IP); Message transfer part 2 User Adaptation layer (M2UA) [Endorsement of RFC 3331 (2002), modified]

SIST-TS ETSI/TS 102 141 V1.1.1:2005 is a SIST technical specification for the Services and Protocols for Advanced Networks (SPAN) family. It endorses RFC 3331 with ETSI modifications and specifies how Message transfer part 2 User Adaptation layer (M2UA) works with Stream Control Transmission Protocol (SCTP) to carry Signalling System No.7 (SS7) Message Transfer Part 3 (MTP3) messages over Internet Protocol (IP). It is aimed at people implementing or integrating signalling gateway and application server functions in SS7 over IP networks.

What does SIST-TS ETSI/TS 102 141 V1.1.1:2005 specify?

SIST-TS ETSI/TS 102 141 V1.1.1:2005 specifies the requirements for M2UA when used with SCTP for transport of SS7 MTP3 messages over IP. It endorses RFC 3331 and constrains it where ETSI needs additional rules or restrictions.

The document is organized into Scope, References, Abbreviations, general considerations for SS7 over IP, M2UA-specific considerations, and a final clause that lists modifications to RFC 3331. That structure matters in practice because implementers can separate the common SIGTRAN rules from the M2UA-specific ETSI constraints.

What are the key requirements of SIST-TS ETSI/TS 102 141 V1.1.1:2005?

Transport, protocol and signalling behavior

SIST-TS ETSI/TS 102 141 V1.1.1:2005 requires SCTP as the transport protocol for SS7 signalling over IP, and it points implementers to the SCTP specification in TS 102 144. TCP shall not be used for M2UA. In practice, this fixes the transport behavior and avoids incompatible deployments.

The document also requires the correct IANA payload protocol identifier for adaptation-layer messages, and unrecognized payload identifiers are to be silently discarded. Unordered user messages shall not be used. This affects interoperability and message handling on the wire.

Configuration, registration and management

SIST-TS ETSI/TS 102 141 V1.1.1:2005 does not allow dynamic registration for configuration management. Configuration shall be changed by the management system, not by the protocol itself. Link Key Management procedures and M2UA registration messages are therefore not used for configuration.

If a message with an unrecognized class is received, the node shall return a Management Error with the error code “Unsupported Message Class”. That gives implementers a defined error path instead of ad hoc handling.

Application Server and ASP state handling

SIST-TS ETSI/TS 102 141 V1.1.1:2005 defines how an Application Server (AS) behaves when multiple Application Server Processes (ASPs) are present. The AS becomes active when the first ASP becomes active and stays active until the last ASP becomes inactive. For operators, that determines when traffic should be accepted or withdrawn.

Broadcast mode shall not be used. Where load sharing is used, the SGP shall take SS7 message sequencing constraints into account. This matters because signalling traffic cannot be rebalanced in a way that breaks message order.

Message classes, streams and procedure rules

SIST-TS ETSI/TS 102 141 V1.1.1:2005 restricts which message classes and message types may be used. Management and ASPSM messages use SCTP stream 0, ASPTM uses a traffic stream, and MAUP messages use any stream except 0. Interface Identifier Management (IIM) messages shall not be used.

Heartbeat procedures are not required: BEAT shall not be sent, and received BEAT or BEAT ACK messages are handled in a defined way. The document also defines timed ASP Up, ASP Down and ASP Active procedures, so implementations know when to wait for acknowledgements and when to notify Layer Management.

What terms does SIST-TS ETSI/TS 102 141 V1.1.1:2005 define?

• AS - Application Server: the logical server that carries SS7 traffic and can contain one or more ASPs.
• ASP - Application Server Process: a process that provides the signalling service for an AS and changes state between active and inactive.
• SG - Signalling Gateway: the network element that connects SS7 signalling into the IP-based adaptation layer.
• SGP - Signalling Gateway Process: the process role inside the signalling gateway that handles M2UA signaling.
• M2UA - Message transfer part level 2 User Adaptation layer: the adaptation layer named in the document, used here for transporting MTP3-related traffic over IP.
• SCTP - Stream Control Transmission Protocol: the transport protocol required for M2UA in this specification.
• SS7 - Signalling System Number 7: the signalling system whose MTP3 traffic is carried over IP.

Who uses SIST-TS ETSI/TS 102 141 V1.1.1:2005?

SIST-TS ETSI/TS 102 141 V1.1.1:2005 is used by telecom equipment vendors, signalling gateway and media gateway controller designers, and operators that carry SS7 over IP. It is also relevant to test labs and quality teams checking interoperability, message handling, state transitions, and management behavior for M2UA-based systems.

What changed in SIST-TS ETSI/TS 102 141 V1.1.1:2005 from the previous edition?

SIST-TS ETSI/TS 102 141 V1.1.1:2005 endorses RFC 3331 with ETSI modifications. The stated changes include removing ANSI references, adding EN 300 008-1, requiring SCTP instead of TCP, disallowing broadcast mode and dynamic registration for configuration management, and tightening several management and message-handling rules.

Which standards are used with SIST-TS ETSI/TS 102 141 V1.1.1:2005?

• ETSI EN 300 008-1 - provides the MTP protocol specification used as the SS7 reference baseline.
• IETF RFC 3331 - defines the base M2UA protocol that this document endorses and modifies.
• ITU-T Q.701, Q.702, Q.703 - provide the MTP functional, data link, and signalling link behavior referenced for M2UA operation.
• ETSI TS 102 142 - gives the M3UA companion specification in the same SPAN and SIGTRAN family.
• ETSI TS 102 143 - gives the SUA companion specification.
• ETSI TS 102 144 - specifies SCTP for this environment.

What does the SIST-TS ETSI/TS 102 141 V1.1.1:2005 document contain?

SIST-TS ETSI/TS 102 141 V1.1.1:2005 contains a clause-by-clause endorsement of RFC 3331, plus ETSI-specific restrictions and additions. It covers transport protocol choice, payload identifiers, AS/ASP state handling, management primitives, stream assignment, heartbeat handling, error handling, and link-key and registration behavior.

It also includes procedural text for ASP Up, ASP Down, ASP Active and ASP Inactive exchanges, together with notes on congestion handling and SS7 interworking. The final clause lists detailed modifications to RFC 3331, and the document also gives message-flow examples for link changeover and buffer-clearing behavior, which are useful for implementation and conformance testing.

SLOVENSKI STANDARD
01-januar-2005
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SUHQRV66SUHNR,3±8SRUDEQLãNDSULODJRGLOQDSODVWVSRURþLOQRSUHQRVQHJD
GHOD08$>SUHY]HWL5)&VSUHPHQMHQ@
Services and Protocols for Advanced Networks (SPAN); MTP/SCCP/SSCOP and
SIGTRAN (Transport of SS7 over IP); Message transfer part 2 User Adaptation layer
(M2UA) [Endorsement of RFC 3331 (2002), modified]
Ta slovenski standard je istoveten z: TS 102 141 Version 1.1.1
ICS:
33.040.01 Telekomunikacijski sistemi Telecommunication systems
na splošno in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

Technical Specification
Services and Protocols for Advanced Networks (SPAN);
MTP/SCCP/SSCOP and SIGTRAN (Transport of SS7 over IP);
Message transfer part 2 User Adaptation layer (M2UA)
[Endorsement of RFC 3331 (2002), modified]

2 ETSI TS 102 141 V1.1.1 (2003-05)

Reference
DTS/SPAN-130262
Keywords
M2UA, MTP, SCCP, SS7, SIGTRAN,
endorsement
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ETSI
3 ETSI TS 102 141 V1.1.1 (2003-05)
Contents
Intellectual Property Rights.4
Foreword.4
Endorsement notice .4
Introduction .4
1 Scope.5
2 References.5
3 Abbreviations.5
4 General considerations applicable to transport of Signalling System No.7 over IP.6
4.1 Transport protocol.6
4.2 SCTP considerations.6
4.3 National options.6
4.4 Application Server mode.6
4.5 Application Server state handling.7
4.6 Dynamic registration.7
4.7 Message distribution to the Application Server.7
4.8 Receipt of unrecognized messages.7
5 Considerations applicable to M2UA .7
5.1 M2UA procedures.7
5.2 National options.7
5.3 Dynamic registration.7
5.4 Message distribution to the Application Server.7
5.5 Using of the terms MGC (Media Gateway Controller) and ASP (Application Server process) .7
6 Modifications to RFC 3331.8
History .15

ETSI
4 ETSI TS 102 141 V1.1.1 (2003-05)
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).
All published ETSI deliverables shall include information which directs the reader to the above source of information.
Foreword
This Technical Specification (TS) has been produced by ETSI Technical Committee Services and Protocols for
Advanced Networks (SPAN).
Endorsement notice
The elements of Internet Engineering Task Force Request for Comments RFC 3331 apply, with the following
modifications.
Introduction
The present document records the changes to the Internet Engineering Task Force (IETF) RFC 3331 [2] document.
RFC 3331 [2] specifies an Internet standard track protocol for the backhauling of Signalling Systems No.7 (SS7)
Message Transfer Part 2 (SS7 MTP2) User signalling messages over IP using the Stream Control Transmission Protocol
(SCTP) (see RFC 3331 [2]).
ETSI
5 ETSI TS 102 141 V1.1.1 (2003-05)
1 Scope
The present document specifies the requirements for the MTP2 User Adaptation layer (M2UA), when used in
conjunction with the Stream Control Transmission Protocol (SCTP) for the transport of the Signalling System
No.7 (SS7) Message Transport Part 3 (MTP3) messages over the Internet Protocol (IP). The document endorses and
constrains where relevant the SIGTRAN (IETF) RFC 3331 [2] of M2UA.
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.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
[1] ETSI EN 300 008-1: "Integrated Services Digital Network (ISDN); Signalling System No.7;
Message Transfer Part (MTP) to support international interconnection; Part 1: Protocol
specification [ITU-T Recommendations Q.701 (1993), Q.702 (1988), Q.703 to Q.706 (1993),
modified]".
[2] IETF RFC 3331: "Signaling System 7 (SS7) Message Transfer Part 2 (MTP2) - User Adaptation
Layer".
NOTE: At http://www.ietf.org/rfc/rfc3331.txt.
[3] ITU-T Recommendation Q.701: "Functional description of the message transfer part (MTP) of
Signalling System No. 7".
[4] ITU-T Recommendation Q.702: "Signalling data link".
[5] ITU-T Recommendation Q.703: "Signalling link".
[6] ETSI TS 102 142: "Services and Protocols for Advanced Networks (SPAN); MTP/SCCP/SSCOP
and SIGTRAN (Messag of SS7 over IP); Message transfer part 3 User Adaptation layer (M3UA)
[Endorsement of RFC 3332 (2002), modified]".
[7] ETSI TS 102 143: "Services and Protocols for Advanced Networks (SPAN); MTP/SCCP/SSCOP
and SIGTRAN (Transport of SS7 over IP); Signalling connection control part User Adaptation
layer (SUA) [Endorsement of SIGTRAN-SUA-14 (December 2002), modified]".
[8] ETSI TS 102 144: "Services and Protocols for Advanced Networks (SPAN); MTP/SCCP/SSCOP
and SIGTRAN (Transport of SS7 over IP); Stream Control Transmission Protocol (SCTP)
[Endorsement of RFC 2960 and RFC 3309, modified]".
3 Abbreviations
For the purposes of the present document, the following abbreviations apply:
AS Application Server
ASP Application Server Process
ASPAC ASP ACtive
ASPIA ASP InActive
ETSI
6 ETSI TS 102 141 V1.1.1 (2003-05)
ASPSM Application Server Process State Maintenance
ASPTM ASP Traffic Management
BEAT heartBEAT
BEAT ACK heartBEAT ACK
DEREG REQ DE-REGistration REQuest
DEREG RSP DE-REGistration ReSPonse
ERR ERroR
IANA Internet Assigned Numbers Authority
IETF Internet Engineering Task Force
IIM Interface Identifier Management
IP Internet Protocol
M2UA Message transfer part level 2 User Adaptation layer
MAUP MAUP
NOTE: Is used in RFC for MTP2 User adaption.
MGC Media Gateway Controller
MTP Message Transfer Part
MTP2 Message Transfer Part level 2, the signalling data link layer over SS7
MTP3 Message Transfer Part level 3, the signalling network layer over SS7
NTFY NoTiFY
REG REQ REGistration REQuest
REG RSP REGistration ReSPonse
SCTP Stream Control Transmission Protocol
SG Signalling Gateway
SGP Signalling Gateway Process
SS7 Signalling System Number 7
4 General considerations applicable to transport of
Signalling System No.7 over IP
The elements of SIGTRAN adaptation layers apply with the following exceptions and restrictions. The considerations
in this clause are common to the present document, TS 102 142 [6] and TS 102 143 [7].
4.1 Transport protocol
The protocol underlying the adaptation layer for transport of SS No.7 signalling information in IP networks shall be
SCTP.
4.2 SCTP considerations
The SCTP used shall conform to TS 102 144 [8].
The SCTP payload protocol identifier for messages pertaining to an adaptation layer shall be the one assigned by IANA
for that layer. Adaptation layer messages received with neither the IANA payload protocol identifier nor payload
protocol identifier equal to 0 shall be silently discarded.
Unordered user messages shall not be used.
4.3 National options
No national options excluded by ETSI standards shall apply to the present document.
4.4 Application Server mode
The Broadcast mode shall not be used.
ETSI
7 ETSI TS 102 141 V1.1.1 (2003-05)
4.5 Application Server state handling
If multiple Application Server Processes (ASPs) are used within the AS, the AS shall be considered active when the
first ASP becomes active, and shall remain active until the last ASP becomes inactive.
4.6 Dynamic registration
Dynamic registration shall not be used for configuration management. The configuration of the system shall be
modified only by the management system, and not by the protocol itself.
4.7 Message distribution to the Application Server
The key to enable messages to be distributed to the appropriate AS shall have a granularity no smaller than is allowed
by the management messages appropriate to that layer.
4.8 Receipt of unrecognized messages
If a message with an unrecognized message class is received, a Management Error message shall be returned with Error
Code "Unsupported Message Class".
5 Considerations applicable to M2UA
5.1 M2UA procedures
The M2UA procedures shall be as defined in RFC 3331 [2] augmented by ITU-T Recommendations Q.701 [3],
Q.702 [4] and Q.703 [5] as modified by EN 300 008-1 [1], except where otherwise defined below.
5.2 National options
No national options excluded by EN 300 008-1 [1] shall apply to the present document.
5.3 Dynamic registration
Dynamic registration of Link Keys shall not be used for configuration management. The configuration of the system
shall be modified only by the management system, and not by the protocol itself.
5.4 Message distribution to the Application Server
No special considerations for message distribution to the Application Server apply for M2UA.
5.5 Using of the terms MGC (Media Gateway Controller) and
ASP (Application Server process)
The terms "MGC" and "ASP" have the same meaning in the present document.
ETSI
8 ETSI TS 102 141 V1.1.1 (2003-05)
6 Modifications to RFC 3331
Modifications to RFC 3331 [2] are listed according to the sections and subsections of RFC 3331 [2].
Section 1 Introduction
ANSI references do not apply. Add a reference EN 300 008-1 [1].
Subsection 1.3 M2UA Overview
ANSI references do not apply. Add a reference EN 300 008-1 [1].
Subsection 1.3.1 Example - SG to MGC
SCTP shall be used as the transport protocol for M2UA. TCP shall not be used as the transport protocol for M2UA.
Subsection 1.3.3 Client/Server Model
The SGP shall be able to support SCTP server operation and the ASP shall be able to support SCTP client operation.
Support of both SCTP client and SCTP server operation at the ASP or SGP is optional.
Subsection 1.4.2 Support for communication between Layer Management modules on SG and MGC
NOTE: M-ERROR is a primitive, not a message.
Subsection 1.4.3 Support for management of active associations between SG and MGC
The M2UA layer shall inform its local Layer Management of the status of its underlying SCTP associations. This is
done by use of the M-SCTP_STA
...