Re: [MEDIACTRL] Control Framework SDP Review - Issue 1

"Jonathan Lennox" <jonathan@vidyo.com> Fri, 02 October 2009 15:00 UTC

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Date: Fri, 02 Oct 2009 11:01:34 -0400
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Thread-Topic: [MEDIACTRL] Control Framework SDP Review - Issue 1
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From: Jonathan Lennox <jonathan@vidyo.com>
To: Chris Boulton <chris@ns-technologies.com>, mediactrl@ietf.org
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Subject: Re: [MEDIACTRL] Control Framework SDP Review - Issue 1
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Just to re-iterate one point in my original e-mail, though -- this would
mean that you'd either have to normatively depend on the SCTP-comedia
draft (which is still an individual submission), or drop SCTP support
from this draft.
	
-- 
Jonathan Lennox
Vidyo, Inc
jonathan@vidyo.com


> -----Original Message-----
> From: mediactrl-bounces@ietf.org [mailto:mediactrl-bounces@ietf.org]
On
> Behalf Of Chris Boulton
> Sent: Friday, October 02, 2009 6:53 AM
> To: mediactrl@ietf.org
> Subject: [MEDIACTRL] Control Framework SDP Review - Issue 1
> 
> Jonathan Lennox has kindly provided expert SDP review for the Media
> Control Channel Framework document.  This is the first in a series of
> emails intended to address the points raised.  At this final stage
your
> input is extremely important.
> 
> 
> My first comment is on the use of the values "TCP/CFW", "TCP/TLS/CFW",
> "SCTP/CFW" and "SCTP/TLS/CFW" for the SDP <proto> field, with a "fmt"
> field of "*".  A more usual use of the proto field would be to use the
> existing proto fields "TCP", "TCP/TLS", "SCTP", or "SCTP/DTLS", and
> then
> (after defining "application/cfw" as a media type) use "cfw" as the
> <fmt> field.
> 
> Thus, instead of having
> 
> m=application 7575 TCP/CFW *
> 
> you'd have
> 
> m=application 7575 TCP cfw
> 
> This has the advantage of leveraging other existing work in SDP, e.g.
> you would get ICE-TCP "for free" once it's finished.
> 
> 
> To be sure, there would be some disadvantages of this.
> 
> Notably, "SCTP" and "SCTP/DTLS" are still only defined in an
individual
> I-D, and there's been only limited attention paid to it in the MMUSIC
> community.  On the other hand, if Mediactrl has the expertise to
> understand how SCTP should work in a comedia context, it'd probably be
> better to let this be available to everything that would want to use
> it,
> rather than just CFW.
> 
> [Chris] I agreed that the proposed change is more elegant and if it
> means that we get ICE-TCP for free then its a bonus.  It is  the
> recommendation of the authors that this change is made to the draft.
> Any comments or objections?
> 
> --
> Chris Boulton
> CTO & Co-founder
> NS-Technologies <http://www.ns-technologies.com>
> m: +44.7876.476681
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