Session Description Protocol (SDP) Media Capabilities Negotiation
RFC 6871

Internet Engineering Task Force (IETF)                         R. Gilman
Request for Comments: 6871                                   Independent
Updates: 5939                                                    R. Even
Category: Standards Track                            Huawei Technologies
ISSN: 2070-1721                                             F. Andreasen
                                                           Cisco Systems
                                                           February 2013

   Session Description Protocol (SDP) Media Capabilities Negotiation

Abstract

   Session Description Protocol (SDP) capability negotiation provides a
   general framework for indicating and negotiating capabilities in SDP.
   The base framework defines only capabilities for negotiating
   transport protocols and attributes.  This documents extends the
   framework by defining media capabilities that can be used to
   negotiate media types and their associated parameters.

   This document updates the IANA Considerations of RFC 5939.

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/rfc6871.

Gilman, et al.               Standards Track                    [Page 1]
RFC 6871           SDP Media Capabilities Negotiation      February 2013

Copyright Notice

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   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
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   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
   10, 2008.  The person(s) controlling the copyright in some of this
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   modifications of such material outside the IETF Standards Process.
   Without obtaining an adequate license from the person(s) controlling
   the copyright in such materials, this document may not be modified
   outside the IETF Standards Process, and derivative works of it may
   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.

Gilman, et al.               Standards Track                    [Page 2]
RFC 6871           SDP Media Capabilities Negotiation      February 2013

Table of Contents

   1. Introduction ....................................................4
   2. Terminology .....................................................4
   3. SDP Media Capabilities ..........................................6
      3.1. Requirements ...............................................6
      3.2. Solution Overview ..........................................7
      3.3. New Capability Attributes .................................13
           3.3.1. The Media Format Capability Attributes .............13
           3.3.2. The Media Format Parameter Capability Attribute ....16
           3.3.3. The Media-Specific Capability Attribute ............19
           3.3.4. New Configuration Parameters .......................21
           3.3.5. The Latent Configuration Attribute .................23
           3.3.6. Enhanced Potential Configuration Attribute .........25
           3.3.7. Substitution of Media Payload Type Numbers
                  in Capability ......................................29
           3.3.8. The Session Capability Attribute ...................30
      3.4. Offer/Answer Model Extensions .............................35
           3.4.1. Generating the Initial Offer .......................35
           3.4.2. Generating the Answer ..............................39
           3.4.3. Offerer Processing of the Answer ...................43
           3.4.4. Modifying the Session ..............................43