Negotiating Media Multiplexing Using the Session Description Protocol (SDP)
RFC 8843

Document Type RFC - Proposed Standard (January 2021; Errata)
Authors Christer Holmberg  , Harald Alvestrand  , Cullen Jennings 
Last updated 2021-02-18
Replaces draft-holmberg-mmusic-sdp-bundle-negotiation
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Document shepherd Flemming Andreasen
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IESG IESG state RFC 8843 (Proposed Standard)
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Internet Engineering Task Force (IETF)                       C. Holmberg
Request for Comments: 8843                                      Ericsson
Updates: 3264, 5888, 7941                                  H. Alvestrand
Category: Standards Track                                         Google
ISSN: 2070-1721                                              C. Jennings
                                                                   Cisco
                                                            January 2021

 Negotiating Media Multiplexing Using the Session Description Protocol
                                 (SDP)

Abstract

   This specification defines a new Session Description Protocol (SDP)
   Grouping Framework extension called 'BUNDLE'.  The extension can be
   used with the SDP offer/answer mechanism to negotiate the usage of a
   single transport (5-tuple) for sending and receiving media described
   by multiple SDP media descriptions ("m=" sections).  Such transport
   is referred to as a BUNDLE transport, and the media is referred to as
   bundled media.  The "m=" sections that use the BUNDLE transport form
   a BUNDLE group.

   This specification defines a new RTP Control Protocol (RTCP) Source
   Description (SDES) item and a new RTP header extension.

   This specification updates RFCs 3264, 5888, and 7941.

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 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   https://www.rfc-editor.org/info/rfc8843.

Copyright Notice

   Copyright (c) 2021 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
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   publication of this document.  Please review these documents
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   include Simplified BSD License text as described in Section 4.e of
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   described in the Simplified BSD License.

   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
   material may not have granted the IETF Trust the right to allow
   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
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   it for publication as an RFC or to translate it into languages other
   than English.

Table of Contents

   1.  Introduction
     1.1.  Background
     1.2.  BUNDLE Mechanism
     1.3.  Protocol Extensions
     1.4.  Contradiction regarding bundle-only "m=" sections
   2.  Terminology
   3.  Conventions
   4.  Applicability Statement
   5.  SDP Grouping Framework BUNDLE Extension
   6.  SDP 'bundle-only' Attribute
   7.  SDP Offer/Answer Procedures
     7.1.  Generic SDP Considerations
       7.1.1.  Connection Data ("c=")
       7.1.2.  Bandwidth ("b=")
       7.1.3.  Attributes ("a=")
     7.2.  Generating the Initial SDP Offer
       7.2.1.  Suggesting the Offerer-Tagged 'm=' Section
       7.2.2.  Example: Initial SDP Offer
     7.3.  Generating the SDP Answer
       7.3.1.  Answerer Selection of Tagged 'm=' Sections
       7.3.2.  Moving a Media Description Out of a BUNDLE Group
       7.3.3.  Rejecting a Media Description in a BUNDLE Group
       7.3.4.  Example: SDP Answer
     7.4.  Offerer Processing of the SDP Answer
     7.5.  Modifying the Session
       7.5.1.  Adding a Media Description to a BUNDLE Group
       7.5.2.  Moving a Media Description Out of a BUNDLE Group
       7.5.3.  Disabling a Media Description in a BUNDLE Group
   8.  Protocol Identification
     8.1.  STUN, DTLS, and SRTP
   9.  RTP Considerations
     9.1.  Single RTP Session
       9.1.1.  Payload Type (PT) Value Reuse
     9.2.  Associating RTP/RTCP Streams with the Correct SDP Media
           Description
     9.3.  RTP/RTCP Multiplexing
       9.3.1.  SDP Offer/Answer Procedures
   10. ICE Considerations
   11. DTLS Considerations
   12. RTP Header Extensions Consideration
   13. Update to RFC 3264
     13.1.  Original Text from RFC 3264, Section 5.1, 2nd Paragraph
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