V5.2-User Adaptation Layer (V5UA)
RFC 3807

Network Working Group                                        E. Weilandt
Request for Comments: 3807                               N. Khanchandani
Updates: 3057                                                     S. Rao
Category: Standards Track                                Nortel Networks
                                                               June 2004

                   V5.2-User Adaptation Layer (V5UA)

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 (2004).

Abstract

   This document defines a mechanism for the backhauling of V5.2
   messages over IP using the Stream Control Transmission Protocol
   (SCTP).  This protocol may be used between a Signaling Gateway (SG)
   and a Media Gateway controller (MGC).  It is assumed that the SG
   receives V5.2 signaling over a standard V5.2 interface.

   This document builds on the ISDN User Adaptation Layer Protocol (RFC
   3057).  It defines all necessary extensions to the IUA Protocol
   needed for the V5UA protocol implementation.

Weilandt, et al.            Standards Track                     [Page 1]
RFC 3807           V5.2-User Adaptation Layer (V5UA)           June 2004

Table of Contents

   1.  Introduction .................................................  2
       1.1.  Scope ..................................................  3
       1.2.  Terminology ............................................  3
       1.3.  V5.2 Overview ..........................................  5
       1.4.  Distribution of responsibilities between MGC and SG ....  7
       1.5.  Client/Server Model ....................................  7
       1.6.  Addition to boundary primitives ........................  7
             1.6.1.  V5 specific boundary primitives ................  7
   2.  Conventions ..................................................  9
   3.  SCTP Stream Management ....................................... 10
   4.  Proposed V5.2 Backhaul Architecture .......................... 10
       4.1.  V5UA Message Header .................................... 11
       4.2.  V5 Naming Conventions for Interface Identifier ......... 12
       4.3.  V5 Additions to IUA Boundary Primitives ................ 13
       4.4.  Link Status Messages ................................... 14
       4.5.  Sa-Bit Messages ........................................ 16
       4.6.  Error Indication Message ............................... 17
   5.  Procedures ................................................... 18
       5.1.  V5 Layer 1 failure ..................................... 18
       5.2.  Loss of V5UA peer ...................................... 19
       5.3.  C-channel overload on SG ............................... 19
   6.  Examples ..................................................... 20
       6.1.  Link Identification Procedure (successful) ............. 20
   7.  Security Considerations ...................................... 21
   8.  IANA Considerations .......................................... 21
       8.1.  SCTP Payload Protocol Identifier ....................... 21
       8.2.  V5UA Port Number ....................................... 22
   9.  Acknowledgements ............................................. 22
   10. References ................................................... 22
       10.1. Normative References ................................... 22
       10.2. Informative References ................................. 23
   11. Authors' Addresses ........................................... 23
   12. Full Copyright Statement ..................................... 24

1.  Introduction

   This document describes a method of implementing V5.2 backhaul
   messaging over IP using a modified version of the ISDN User
   Adaptation Layer Protocol (IUAP) [1].  V5UA builds on top of IUA,
   defining the necessary extensions to IUA for a V5.2 implementation.

   Since V5UA is meant to be an extension to IUAP, everything defined in
   [1] is also valid for V5UA unless otherwise specified in this
   document.

Weilandt, et al.            Standards Track                     [Page 2]
RFC 3807           V5.2-User Adaptation Layer (V5UA)           June 2004

   This document does not describe the V5 standard itself.  The V5
   protocol is defined by ETSI standards [2,3].  Any description of the
   V5 protocol in this document is meant to make the text easier to