Signaling System 7 (SS7) Message Transfer Part 2 (MTP2) - User Adaptation Layer
RFC 3331

• Status
• IESG evaluation record
• IESG writeups
• Email expansions
• History

• Versions
• 15

Network Working Group                                       K. Morneault
Request for Comments: 3331                                 Cisco Systems
Category: Standards Track                                       R. Dantu
                                                                 NetRake
                                                           G. Sidebottom
                                                   Signatus Technologies
                                                             B. Bidulock
                                                                 OpenSS7
                                                                J. Heitz
                                                                  Lucent
                                                          September 2002

       Signaling System 7 (SS7) Message Transfer Part 2 (MTP2) -
                         User Adaptation Layer

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2002).  All Rights Reserved.

Abstract

   This document defines a protocol for the backhauling of Signaling
   System 7 Message Transfer Part 2 (SS7 MTP2) User signalling messages
   over IP using the Stream Control Transmission Protocol (SCTP).  This
   protocol would be used between a Signalling Gateway (SG) and Media
   Gateway Controller (MGC).  It is assumed that the SG receives SS7
   signalling over a standard SS7 interface using the SS7 Message
   Transfer Part (MTP) to provide transport.  The Signalling Gateway
   would act as a Signalling Link Terminal.

Morneault, et. al.          Standards Track                     [Page 1]
RFC 3331             SS7 MTP2 User Adaptation Layer       September 2002

Table of Contents

   1.  Introduction.............................................. 2
     1.1  Scope.................................................. 3
     1.2  Terminology............................................ 3
     1.3  M2UA Overview.......................................... 5
     1.4  Services Provided by the M2UA Adaptation Layer......... 7
     1.5  Functions Provided by the M2UA Layer................... 9
     1.6  Definition of the M2UA Boundaries..................... 12
   2.  Conventions.............................................. 16
   3.  Protocol Elements........................................ 16
     3.1  Common Message Header................................. 16
     3.2  M2UA Message Header................................... 22
     3.3  M2UA Messages......................................... 23
   4.  Procedures............................................... 58
     4.1  Procedures to Support the M2UA-User Layer............. 58
     4.2  Receipt of Primitives from the Layer Management....... 59
     4.3  AS and ASP State Maintenance.......................... 61
     4.4  Link Key Management Procedures........................ 73
   5.  Examples of MTP2 User Adaptation (M2UA) Procedures....... 75
     5.1  Establishment of associations between SGP and MGC..... 75
          examples
     5.2  ASP Traffic Fail-over Examples........................ 77
     5.3  SGP to MGC, MTP Level 2 to MTP Level 3 Boundary
          Procedures............................................ 78
   6.  Timer Values............................................. 85
   7.  Security Considerations.................................. 85
     7.1 Threats................................................ 85
     7.2 Protecting Confidentiality............................. 86
   8.  IANA Considerations...................................... 86
     8.1 SCTP Payload Protocol Identifier....................... 86
     8.2 M2UA Protocol Extensions............................... 86
   9.  Acknowledgements......................................... 87
   10. References............................................... 88
   Appendix A: Signalling Network Architecture.................. 90
   Authors' Addresses........................................... 92
   Full Copyright Statement..................................... 94

1.  Introduction

   This document defines a protocol for the backhauling of SS7 [1] MTP2
   User [2] [3] [4] (i.e. MTP3) signalling messages over IP using the
   Stream Control Transmission Protocol (SCTP) [8].  This protocol would
   be used between a Signalling Gateway (SG) and Media Gateway
   Controller (MGC).

Morneault, et. al.          Standards Track                     [Page 2]
RFC 3331             SS7 MTP2 User Adaptation Layer       September 2002

1.1 Scope

   There is a need for Switched Circuit Network (SCN) signalling
   protocol delivery from a Signalling Gateway (SG) to a Media Gateway