RTP Stream Identifier Source Description (SDES)
draft-ietf-avtext-rid-09

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Network Working Group                                           A. Roach
Internet-Draft                                                   Mozilla
Intended status: Standards Track                           S. Nandakumar
Expires: April 9, 2017                                     Cisco Systems
                                                             P. Thatcher
                                                                  Google
                                                        October 06, 2016

            RTP Stream Identifier Source Description (SDES)
                        draft-ietf-avtext-rid-09

Abstract

   This document defines and registers two new RTCP Stream Identifier
   Source Description (SDES) items.  One, named RtpStreamId, is used for
   unique identification of RTP streams.  The other,
   RepairedRtpStreamId, can be used to identify which stream a
   redundancy RTP stream is to be used to repair.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on April 9, 2017.

Copyright Notice

   Copyright (c) 2016 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

Roach, et al.             Expires April 9, 2017                 [Page 1]
Internet-Draft              RtpStreamId SDES                October 2016

   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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Usage of RtpStreamId and RepairedRtpStreamId in RTP and RTCP    3
     3.1.  RTCP 'RtpStreamId' SDES Extension . . . . . . . . . . . .   5
     3.2.  RTCP 'RepairedRtpStreamId' SDES Extension . . . . . . . .   5
     3.3.  RTP 'RtpStreamId' and 'RepairedRtpStreamId' Header
           Extensions  . . . . . . . . . . . . . . . . . . . . . . .   5
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
     4.1.  New RtpStreamId SDES item . . . . . . . . . . . . . . . .   6
     4.2.  New RepairRtpStreamId SDES item . . . . . . . . . . . . .   6
     4.3.  New RtpStreamId Header Extension URI  . . . . . . . . . .   7
     4.4.  New RepairRtpStreamId Header Extension URI  . . . . . . .   7
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   8
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   8
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   RTP sessions frequently consist of multiple streams, each of which is
   identified at any given time by its SSRC; however, the SSRC
   associated with a stream is not guaranteed to be stable over its
   lifetime.  Within a session, these streams can be tagged with a
   number of identifiers, including CNAMEs and MSIDs
   [I-D.ietf-mmusic-msid].  Unfortunately, none of these have the proper
   ordinality to refer to an individual stream; all such identifiers can
   appear in more than one stream at a time.  While approaches that use
   unique Payload Types (PTs) per stream have been used in some
   applications, this is a semantic overloading of that field, and one
   for which its size is inadequate: in moderately complex systems that
   use PT to uniquely identify every potential combination of codec
   configuration and unique stream, it is possible to simply run out of
   values.

   To address this situation, we define a new RTCP Stream Identifier
   Source Description (SDES) identifier, RtpStreamId, that uniquely
   identifies a single RTP stream.  A key motivator for defining this
   identifier is the ability to differentiate among different encodings