IPv6 Transition in the Session Initiation Protocol (SIP)
RFC 6157

Internet Engineering Task Force (IETF)                      G. Camarillo
Request for Comments: 6157                                      Ericsson
Updates: 3264                                                K. El Malki
Category: Standards Track                                        Athonet
ISSN: 2070-1721                                               V. Gurbani
                                               Bell Labs, Alcatel-Lucent
                                                              April 2011

        IPv6 Transition in the Session Initiation Protocol (SIP)

Abstract

   This document describes how the IPv4 Session Initiation Protocol
   (SIP) user agents can communicate with IPv6 SIP user agents (and vice
   versa) at the signaling layer as well as exchange media once the
   session has been successfully set up.  Both single- and dual-stack
   (i.e., IPv4-only and IPv4/IPv6) user agents are considered.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6157.

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Camarillo, et al.            Standards Track                    [Page 1]
RFC 6157                 IPv6 Transition in SIP               April 2011

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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  The Signaling Layer  . . . . . . . . . . . . . . . . . . . . .  4
     3.1.  Proxy Behavior . . . . . . . . . . . . . . . . . . . . . .  4
       3.1.1.  Relaying Requests across Different Networks  . . . . .  5
     3.2.  User Agent Behavior  . . . . . . . . . . . . . . . . . . .  7
   4.  The Media Layer  . . . . . . . . . . . . . . . . . . . . . . .  7
     4.1.  Updates to RFC 3264  . . . . . . . . . . . . . . . . . . .  9
     4.2.  Initial Offer  . . . . . . . . . . . . . . . . . . . . . .  9
     4.3.  Connectivity Checks  . . . . . . . . . . . . . . . . . . . 10
   5.  Contacting Servers: Interaction of RFC 3263 and RFC 3484 . . . 10
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 11
   7.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 11
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
     8.1.  Normative References . . . . . . . . . . . . . . . . . . . 12
     8.2.  Informative References . . . . . . . . . . . . . . . . . . 12
   Appendix A.  Sample IPv4/IPv6 DNS File . . . . . . . . . . . . . . 14

1.  Introduction

   SIP [3] is a protocol to establish and manage multimedia sessions.
   After the exchange of signaling messages, SIP endpoints generally
   exchange session or media traffic, which is not transported using SIP
   but a different protocol.  For example, audio streams are typically
   carried using the Real-Time Transport Protocol (RTP) [13].

   Consequently, a complete solution for IPv6 transition needs to handle
   both the signaling layer and the media layer.  While unextended SIP