Subject: [AVT] New draft on rapid sycnhronization in RTP multicast sessions

From: "Ali C. Begen (abegen)" <[email-masked]>
Date: Mon, 3 Nov 2008 14:44:26 -0800

FYI.

We submitted a new version of our draft based on the comments we received in the last AVT meeting. Comments and suggestions are welcome.

http://www.ietf.org/internet-drafts/draft-versteeg-avt-rapid-synchronization-for-rtp-01.txt

BR,
-acbegen

A new version of I-D, draft-versteeg-avt-rapid-synchronization-for-rtp-01.txt has been successfuly submitted by Ali Begen and posted to the IETF repository.

Filename:	 draft-versteeg-avt-rapid-synchronization-for-rtp
Revision:	 01
Title:		 Unicast-Based Rapid Synchronization with RTP Multicast Sessions
Creation_date:	 2008-11-03
WG ID:		 Independent Submission
Number_of_pages: 37

Abstract:
When a receiver joins a multicast session, it may need to acquire and
parse certain key information before it can process any data sent in
the multicast session.  Depending on the join time, length of the key
information repetition interval, size of the key information as well
as the application and transport properties, the time lag before a
receiver can usefully consume the multicast data, which we refer to
as the synchronization delay, varies and may be large.  This is an
undesirable phenomenon for receivers that frequently switch among
different multicast sessions, such as video broadcasts.  In this
document, we describe a method using existing RTP and RTCP protocol
machinery that reduces the synchronization delay.  In this method, an
auxiliary unicast RTP session carrying the key information to the
receiver precedes/accompanies the multicast flow.  This unicast flow
may be transmitted at a faster than natural rate to further
accelerate the synchronization.  The motivating use case for this
capability is multicast applications that carry real-time compressed
audio and video.  However, the proposed method can also be used in
other types of multicast applications where the synchronization delay
is long enough to be a problem.

The IETF Secretariat.

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Audio/Video Transport Working Group
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