Session Initiation Protocol (SIP) INFO Method and Package Framework
RFC 6086

Internet Engineering Task Force (IETF)                       C. Holmberg
Request for Comments: 6086                                      Ericsson
Obsoletes: 2976                                                E. Burger
Category: Standards Track                          Georgetown University
ISSN: 2070-1721                                                H. Kaplan
                                                             Acme Packet
                                                            January 2011

  Session Initiation Protocol (SIP) INFO Method and Package Framework

Abstract

   This document defines a method, INFO, for the Session Initiation
   Protocol (SIP), and an Info Package mechanism.  This document
   obsoletes RFC 2976.  For backward compatibility, this document also
   specifies a "legacy" mode of usage of the INFO method that is
   compatible with the usage previously defined in RFC 2976, referred to
   as "legacy INFO Usage" in this document.

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/rfc6086.

Copyright Notice

   Copyright (c) 2011 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
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Holmberg, et al.             Standards Track                    [Page 1]
RFC 6086                     INFO Framework                 January 2011

Table of Contents

   1. Introduction ....................................................3
      1.1. Conventions Used in This Document ..........................4
   2. Motivation ......................................................4
   3. Applicability and Backward Compatibility ........................5
   4. The INFO Method .................................................6
      4.1. General ....................................................6
      4.2. INFO Request ...............................................6
           4.2.1. INFO Request Sender .................................6
           4.2.2. INFO Request Receiver ...............................7
           4.2.3. SIP Proxies .........................................8
      4.3. INFO Message Body ..........................................8
           4.3.1. INFO Request Message Body ...........................8
           4.3.2. INFO Response Message Body ..........................9
      4.4. Order of Delivery ..........................................9
   5. Info Packages ...................................................9
      5.1. General ....................................................9
      5.2. User Agent Behavior .......................................10
           5.2.1. General ............................................10
           5.2.2. UA Procedures ......................................10
           5.2.3. Recv-Info Header Field Rules .......................11
           5.2.4. Info Package Fallback Rules ........................12
      5.3. REGISTER Processing .......................................12
   6. Formal INFO Method Definition ..................................13
      6.1. INFO Method ...............................................13
   7. INFO Header Fields .............................................15
      7.1. General ...................................................15
      7.2. Info-Package Header Field .................................15
      7.3. Recv-Info Header Field ....................................16
   8. Info Package Considerations ....................................16
      8.1. General ...................................................16
      8.2. Appropriateness of Info Package Usage .....................16
      8.3. INFO Request Rate and Volume ..............................16
      8.4. Alternative Mechanisms ....................................17