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Using Simulcast in RTP Sessions
draft-westerlund-avtcore-rtp-simulcast-03

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Last updated: 2013-10-21
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Network Working Group                                      M. Westerlund
Internet-Draft                                                 B. Burman
Intended status: Standards Track                                Ericsson
Expires: April 25, 2014                                    S. Nandakumar
                                                                   Cisco
                                                        October 22, 2013

                    Using Simulcast in RTP Sessions
               draft-westerlund-avtcore-rtp-simulcast-03

Abstract

   In some application scenarios it may be desirable to send multiple
   differently encoded versions of the same Media Source in independent
   Source Packet Streams.  This is called Simulcast.  This document
   discusses the best way of accomplishing Simulcast in RTP and how to
   signal it in SDP.  A solution is defined by making three extensions
   to SDP, and using RTP/RTCP identification methods to relate RTP
   Source Packet Streams.  The first SDP extension consists of two new
   session level SDP attributes that express capability to send or
   receive Simulcast Source Packet Streams, respectively.  The second
   SDP extension introduces an SDP media level attribute that groups and
   identifies a selected set of media level parameters for a specific
   direction, called a media configuration.  The third SDP extension
   describes how to group such media configurations on SDP session or
   media level for Simulcast purposes.

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
   Task Force (IETF).  Note that other groups may also distribute
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   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on April 25, 2014.

Copyright Notice

Westerlund, et al.       Expires April 25, 2014                 [Page 1]
Internet-Draft                RTP Simulcast                 October 2013

   Copyright (c) 2013 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
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   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  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Definitions . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     2.2.  Requirements Language . . . . . . . . . . . . . . . . . .   4
   3.  Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  Reaching a Diverse Set of Receivers . . . . . . . . . . .   5
     3.2.  Application Specific Media Source Handling  . . . . . . .   6
     3.3.  Receiver Adaptation in Multicast/Broadcast  . . . . . . .   7
     3.4.  Receiver Media Source Preferences . . . . . . . . . . . .   7
   4.  Requirements  . . . . . . . . . . . . . . . . . . . . . . . .   8
   5.  Proposed Solution Overview  . . . . . . . . . . . . . . . . .   9
   6.  Proposed Signaling  . . . . . . . . . . . . . . . . . . . . .  10
     6.1.  Simulcast Capability  . . . . . . . . . . . . . . . . . .  11
       6.1.1.  Declarative Use . . . . . . . . . . . . . . . . . . .  12
       6.1.2.  Offer/Answer Use  . . . . . . . . . . . . . . . . . .  12
     6.2.  Media Configuration . . . . . . . . . . . . . . . . . . .  13
       6.2.1.  Simulcast Limitations . . . . . . . . . . . . . . . .  16
       6.2.2.  Declarative Use . . . . . . . . . . . . . . . . . . .  17
       6.2.3.  Offer/Answer Use  . . . . . . . . . . . . . . . . . .  17
     6.3.  Grouping Simulcast Configurations . . . . . . . . . . . .  18
       6.3.1.  Declarative Use . . . . . . . . . . . . . . . . . . .  19
       6.3.2.  Offer/Answer Use  . . . . . . . . . . . . . . . . . .  19
     6.4.  Relating Simulcast Versions . . . . . . . . . . . . . . .  20
     6.5.  Two-Phase Negotiation . . . . . . . . . . . . . . . . . .  20

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