Message Body Handling in the Session Initiation Protocol (SIP)
RFC 5621

Network Working Group                                       G. Camarillo
Request for Comments: 5621                                      Ericsson
Updates: 3204, 3261, 3459                                 September 2009
Category: Standards Track

     Message Body Handling in the Session Initiation Protocol (SIP)

Abstract

   This document specifies how message bodies are handled in SIP.
   Additionally, this document specifies SIP user agent support for MIME
   (Multipurpose Internet Mail Extensions) in message bodies.

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) 2009 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents in effect on the date of
   publication of this document (http://trustee.ietf.org/license-info).
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.

Camarillo                   Standards Track                     [Page 1]
RFC 5621              Message Body Handling in SIP        September 2009

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  Message Body Encoding  . . . . . . . . . . . . . . . . . . . .  3
     3.1.  Background on Message Body Encoding  . . . . . . . . . . .  3
     3.2.  UA Behavior to Encode Binary Message Bodies  . . . . . . .  5
   4.  'multipart' Message Bodies . . . . . . . . . . . . . . . . . .  6
     4.1.  Background on 'multipart' Message Bodies . . . . . . . . .  6
     4.2.  Mandatory Support for 'multipart' Message Bodies . . . . .  7
     4.3.  UA Behavior to Generate 'multipart' Message Bodies . . . .  7
   5.  'multipart/mixed' Message Bodies . . . . . . . . . . . . . . .  7
   6.  'multipart/alternative' Message Bodies . . . . . . . . . . . .  8
     6.1.  Background on 'multipart/alternative' Message Bodies . . .  8
     6.2.  UA Behavior to Generate 'multipart/alternative'
           Message Bodies . . . . . . . . . . . . . . . . . . . . . .  8
     6.3.  UA Behavior to Process 'multipart/alternative' Message
           Bodies . . . . . . . . . . . . . . . . . . . . . . . . . .  9
   7.  'multipart/related' Message Bodies . . . . . . . . . . . . . .  9
     7.1.  Background on 'multipart/related' Message Bodies . . . . .  9
     7.2.  UA Behavior to Generate 'multipart/related' Message
           Bodies . . . . . . . . . . . . . . . . . . . . . . . . . .  9
     7.3.  UA Behavior to Process 'multipart/related' Message
           Bodies . . . . . . . . . . . . . . . . . . . . . . . . . .  9
   8.  Disposition Types  . . . . . . . . . . . . . . . . . . . . . . 10
     8.1.  Background on Content and Disposition Types in SIP . . . . 10
     8.2.  UA Behavior to Set the 'handling' Parameter  . . . . . . . 12
     8.3.  UA Behavior to Process 'multipart/alternative' . . . . . . 13
     8.4.  UAS Behavior to Report Unsupported Message Bodies  . . . . 13
   9.  Message Body Processing  . . . . . . . . . . . . . . . . . . . 14
     9.1.  Background on References to Message Body Parts . . . . . . 14
     9.2.  UA Behavior to Generate References to Message Bodies . . . 14
     9.3.  UA Behavior to Process Message Bodies  . . . . . . . . . . 14
     9.4.  The 'by-reference' Disposition Type  . . . . . . . . . . . 15
   10. Guidelines to Authors of SIP Extensions  . . . . . . . . . . . 16
   11. Security Considerations  . . . . . . . . . . . . . . . . . . . 16
   12. IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 17
     12.1. Registration of the 'by-reference' Disposition Type  . . . 17
     12.2. Update of the 'handling' Parameter Registration  . . . . . 17
   13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 17
   14. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17
     14.1. Normative References . . . . . . . . . . . . . . . . . . . 17
     14.2. Informative References . . . . . . . . . . . . . . . . . . 18

Camarillo                   Standards Track                     [Page 2]
RFC 5621              Message Body Handling in SIP        September 2009

1.  Introduction