Real-Time Transport Protocol (RTP) Considerations for Endpoints Sending Multiple Media Streams
draft-lennox-avtcore-rtp-multi-stream-00

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Last updated 2012-07-09
Replaced by rfc8108, draft-ietf-avtcore-rtp-multi-stream
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AVTCORE                                                        J. Lennox
Internet-Draft                                                     Vidyo
Updates: 3550 (if approved)                                M. Westerlund
Intended status: Standards Track                                Ericsson
Expires: January 10, 2013                                   July 9, 2012

Real-Time Transport Protocol (RTP) Considerations for Endpoints Sending
                         Multiple Media Streams
                draft-lennox-avtcore-rtp-multi-stream-00

Abstract

   This document expands and clarifies the behavior of the Real-Time
   Transport Protocol (RTP) endpoints when they are sending multiple
   media streams in a single RTP session.  In particular, issues
   involving Real-Time Transport Control Protocol (RTCP) messages are
   described.

Status of this Memo

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

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   This Internet-Draft will expire on January 10, 2013.

Copyright Notice

   Copyright (c) 2012 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
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   (http://trustee.ietf.org/license-info) in effect on the date of
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   include Simplified BSD License text as described in Section 4.e of

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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  Use Cases For Multi-Stream Endpoints . . . . . . . . . . . . .  3
     3.1.  Multiple-Capturer Endpoints  . . . . . . . . . . . . . . .  3
     3.2.  Multi-Media Sessions . . . . . . . . . . . . . . . . . . .  4
     3.3.  Multi-Stream Mixers  . . . . . . . . . . . . . . . . . . .  4
   4.  Multi-Stream Endpoint RTP Media Recommendations  . . . . . . .  4
   5.  Multi-Stream Endpoint RTCP Recommendations . . . . . . . . . .  5
     5.1.  Transmission of RTCP Reception Statistics  . . . . . . . .  6
     5.2.  Consequences of Restricted RTCP Reception Statistics . . .  7
     5.3.  Alternate Restriction Proposal . . . . . . . . . . . . . .  7
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . .  8
   7.  Open Issues  . . . . . . . . . . . . . . . . . . . . . . . . .  8
   8.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  8
   9.  References . . . . . . . . . . . . . . . . . . . . . . . . . .  9
     9.1.  Normative References . . . . . . . . . . . . . . . . . . .  9
     9.2.  Informative References . . . . . . . . . . . . . . . . . .  9
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10

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1.  Introduction

   At the time The Real-Time Tranport Protocol (RTP) [RFC3550] was
   originally written, and for quite some time after, endpoints in RTP
   sessions typically only transmitted a single media stream per RTP
   session, where separate RTP sessions were typically used for each
   distinct media type.

   Recently, however, a number of scenarios have emerged (discussed
   further in Section 3) in which endpoints wish to send multiple RTP
   media streams, distinguished by distinct RTP synchronization source
   (SSRC) identifiers, in a single RTP session.  Although RTP's initial
   design did consider such scenarios, the specification was not
   consistently written with such use cases in mind.  The specifications
   are thus somewhat unclear.

   The purpose of this document is to expand and clarify [RFC3550]'s
   language for these use cases.  The authors believe this does not
   result in any major normative changes to the RTP specification,
   however this document defines how the RTP specification shall be
   interpreted.  In these cases, this document updates RFC3550.
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