Re: [rtcweb] draft on media multiplexing submitted to AVTCORE

["Ejzak, Richard P (Richard)" <[e-mail]>]

Hi Christer,
I agree that BUNDLE in its current form would be consistent with the RTP subsessions proposal, but it would also be technically redundant.  I'm not sure exactly which comments in the paper you object to.  I agree with you about the purpose of BUNDLE and that it works (with limitations) for its intended purpose.  My understanding is that BUNDLE is primarily intended for the case where a single RTP session is shared across m lines.  There is no need for BUNDLE (and specifically the constrained PT assignment) when you use another mechanism such as SHIM or RTP subsessions to segregate the flows associated with each m line.  Whether the grouping framework is applicable is open for discussion.

So perhaps we should separately discuss the grouping framework and constrained PT assignment procedures associated with BUNDLE to be sure we understand one another.  The source of our disagreement may be more what is meant by "BUNDLE" than anything else.  I have no problem redefining it if there is agreement to do so!

I look forward to an in-depth discussion of these issues in Stockholm.

BR, Richard

________________________________
From: Christer Holmberg [mailto:[e-mail]]
Sent: Monday, June 04, 2012 2:23 AM
To: Ejzak, Richard P (Richard); [e-mail]
Subject: RE: [rtcweb] draft on media multiplexing submitted to AVTCORE

Hi Richard,

I will not comment on the RTP aspects of your proposal, but I don't understand your comments regarding BUNDLE.

The core purpose of BUNDLE is to allow the usage of identical IP address:port information for multiple m- lines.

It is true that BUNDLE defines that, by default, all media belong to the same RTP session. But, nothing prevents you from using BUNDLE also with multiple RTP sessions, RTP "subsession" etc. You simply need an extension mechanism  to indicate/negotiate such usage (in your case the ssrc-prefix could perhaps be used for that).

Regards,

Christer

From: [e-mail] [mailto:[e-mail]] On Behalf Of Ejzak, Richard P (Richard)
Sent: 4. kesäkuuta 2012 2:10
To: [e-mail]
Subject: [rtcweb] draft on media multiplexing submitted to AVTCORE

Please see the mail attached below that I just sent to avtcore announcing a personal ID I just submitted on the topic of media multiplexing.  I am sending this notice to rtcweb since this is the group that triggered recent work on RTP multiplexing.

I also request the rtcweb chairs consider giving me some time to present this work at next week's interim meeting if there is time on the agenda.  It might be useful to discuss the ideas in the ID before avtcore meets in Vancouver.

Richard


-----Original Message-----
From: Ejzak, Richard P (Richard)
Sent: Sunday, June 03, 2012 6:08 PM
To: '[e-mail]'
Subject: [AVTCORE] multi session draft-ejzak-avtcore-rtp-subsessions-00.txt



http://www.ietf.org/id/draft-ejzak-avtcore-rtp-subsessions-00.txt



In response to the chairs' request for additional input on the multi session issue, I have submitted this draft for your consideration.  There are superficial similarities with an expired draft from last year in http://tools.ietf.org/id/draft-rosenberg-rtcweb-rtpmux-00.txt, but my draft has a different take on the use of SSRC as the basis for multi session multiplexing that I think is superior and worthy of consideration as a potential replacement for BUNDLE and/or SHIM.  Please comment.



Richard



-----Original Message-----

From: [e-mail]<mailto:[e-mail]> [mailto:[e-mail]]<mailto:%5bmailto:[e-mail]%5d>

Sent: Sunday, June 03, 2012 5:16 PM

To: Ejzak, Richard P (Richard)

Subject: New Version Notification for draft-ejzak-avtcore-rtp-subsessions-00.txt



A new version of I-D, draft-ejzak-avtcore-rtp-subsessions-00.txt has been successfully submitted by Richard Ejzak and posted to the IETF repository.



Filename:   draft-ejzak-avtcore-rtp-subsessions

Revision:   00

Title:            Media multiplexing with Real-time Transport Protocol (RTP) subsessions

Creation date:    2012-06-04

WG ID:            Individual Submission

Number of pages: 9



Abstract:

   This document describes a means of multiplexing RTP streams having

   different media types within a single transport connection and how to

   represent this multiplexing option in SDP.  This mechanism is an

   alternative to the BUNDLE and SHIM proposals currently under active

   consideration in AVTCORE.  Instead of adding an extra multiplexing

   header as in SHIM to allow multiple RTP sessions within a single

   transport connection, or using the payload type field to separate

   different media streams within a single RTP session, this document

   describes how to partition the existing SSRC space to create RTP

   subsessions from a single RTP session.  A filter can be used to

   identify each RTP subsession for different QoS handling as necessary.

   RTP subsessions can be treated like RTP sessions with a few

   restrictions.  In particular, SSRC mapping may be needed when

   forwarding RTP streams into an RTP subsession to avoid SSRC

   conflicts, but there are few use cases in which this limitation is a

   concern and RTP subsessions can be disabled if necessary.









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