RFC 3264 (rfc3264) - Page 1 of 25

An Offer/Answer Model with Session Description Protocol (SDP)

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Network Working Group                                       J. Rosenberg
Request for Comments: 3264                                   dynamicsoft
Obsoletes: 2543                                           H. Schulzrinne
Category: Standards Track                                    Columbia U.
                                                               June 2002


   An Offer/Answer Model with the Session Description Protocol (SDP)

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2002).  All Rights Reserved.

Abstract

   This document defines a mechanism by which two entities can make use
   of the Session Description Protocol (SDP) to arrive at a common view
   of a multimedia session between them.  In the model, one participant
   offers the other a description of the desired session from their
   perspective, and the other participant answers with the desired
   session from their perspective.  This offer/answer model is most
   useful in unicast sessions where information from both participants
   is needed for the complete view of the session.  The offer/answer
   model is used by protocols like the Session Initiation Protocol
   (SIP).

Table of Contents

   1          Introduction ........................................    2
   2          Terminology .........................................    3
   3          Definitions .........................................    3
   4          Protocol Operation ..................................    4
   5          Generating the Initial Offer ........................    5
   5.1        Unicast Streams .....................................    5
   5.2        Multicast Streams ...................................    8
   6          Generating the Answer ...............................    9
   6.1        Unicast Streams .....................................    9
   6.2        Multicast Streams ...................................   12
   7          Offerer Processing of the Answer ....................   12
   8          Modifying the Session ...............................   13



Rosenberg & Schulzrinne     Standards Track
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