Duplication Grouping Semantics in the Session Description Protocol
draft-ietf-mmusic-duplication-grouping-03

The information below is for an old version of the document
Document Type Active Internet-Draft (mmusic WG)
Last updated 2013-11-21 (latest revision 2013-07-11)
Replaces draft-begen-mmusic-redundancy-grouping
Stream IETF
Intended RFC status Proposed Standard
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Stream WG state Submitted to IESG for Publication Jul 2013
Consensus Yes
Document shepherd Ari Keranen
Shepherd write-up Show (last changed 2013-07-29)
IESG IESG state Approved-announcement to be sent::Revised I-D Needed
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Responsible AD Gonzalo Camarillo
Send notices to mmusic-chairs@tools.ietf.org, draft-ietf-mmusic-duplication-grouping@tools.ietf.org
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MMUSIC                                                          A. Begen
Internet-Draft                                                     Cisco
Intended status: Standards Track                                  Y. Cai
Expires: January 12, 2014                                      Microsoft
                                                                   H. Ou
                                                                   Cisco
                                                           July 11, 2013

   Duplication Grouping Semantics in the Session Description Protocol
               draft-ietf-mmusic-duplication-grouping-03

Abstract

   Packet loss is undesirable for real-time multimedia sessions, but can
   occur due to congestion, or other unplanned network outages.  This is
   especially true for IP multicast networks, where packet loss patterns
   can vary greatly between receivers.  One technique that can be used
   to recover from packet loss without incurring unbounded delay for all
   the receivers is to duplicate the packets and send them in separate
   redundant streams.  This document defines the semantics for grouping
   redundant streams in the Session Description Protocol (SDP).  The
   semantics defined in this document are to be used with the SDP
   Grouping Framework.  SSRC-level (Synchronization Source) grouping
   semantics are also defined in this document for RTP streams using
   SSRC multiplexing.

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 January 12, 2014.

Copyright Notice

   Copyright (c) 2013 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Begen, et al.           Expires January 12, 2014                [Page 1]
Internet-Draft    Duplication Grouping Semantics in SDP        July 2013

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Requirements Notation . . . . . . . . . . . . . . . . . . . .   3
   3.  Duplication Grouping  . . . . . . . . . . . . . . . . . . . .   3
     3.1.  "DUP" Grouping Semantics  . . . . . . . . . . . . . . . .   3
     3.2.  Duplication Grouping for SSRC-Multiplexed RTP Streams . .   3
     3.3.  SDP Offer/Answer Model Considerations . . . . . . . . . .   4
   4.  SDP Examples  . . . . . . . . . . . . . . . . . . . . . . . .   4
     4.1.  Separate Source Addresses . . . . . . . . . . . . . . . .   4
     4.2.  Separate Destination Addresses  . . . . . . . . . . . . .   5
     4.3.  Temporal Redundancy . . . . . . . . . . . . . . . . . . .   5
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   7
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   The Real-time Transport Protocol (RTP) [RFC3550] is widely used today
   for delivering IPTV traffic, and other real-time multimedia sessions.
   Many of these applications support very large numbers of receivers,
   and rely on intra-domain UDP/IP multicast for efficient distribution
   of traffic within the network.

   While this combination has proved successful, there does exist a
   weakness.  As [RFC2354] noted, packet loss is not avoidable, even in
   a carefully managed network.  This loss might be due to congestion,
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