Re: [ssm] Re: draft-chesterfield-avt-rtcpssm

Toerless Eckert <eckert@cisco.com> Thu, 07 July 2005 15:49 UTC

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Date: Thu, 7 Jul 2005 08:49:30 -0700
From: Toerless Eckert <eckert@cisco.com>
To: Joerg Ott <jo@informatik.uni-bremen.de>
Subject: Re: [ssm] Re: draft-chesterfield-avt-rtcpssm
Message-ID: <20050707154930.GS834@cisco.com>
References: <20050704200907.GJ834@cisco.com> <80BEB3DC-39BA-43E2-821C-0496922883A7@csperkins.org> <20050704220157.GM834@cisco.com> <C85698BB-C889-46A6-8616-E235BB2888AB@csperkins.org> <20050704224154.GQ834@cisco.com> <893DA83C-641A-4D5F-93FB-BEA7FF596D8A@csperkins.org> <42CCE5FB.7010006@informatik.uni-bremen.de>
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Cc: =?iso-8859-1?Q?J=F6rg?= Ott <jo@netlab.hut.fi>, Julian Chesterfield <jac90@cam.ac.uk>, Magnus Westerlund <magnus.westerlund@ericsson.com>, Colin Perkins <csp@csperkins.org>, ssm@ietf.org
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On Thu, Jul 07, 2005 at 10:21:15AM +0200, Joerg Ott wrote:
> >Sure, I understand that. But from my reading, this draft *does* refer  
> >explicitly to SSM rather than just "multicast" -- what needs to be  
> >changed?
> 
> To add to this, draft-ietf-avt-rtcpssm also discusses how
> non-aggregatable RTCP messages shall be treated.  Thus, it is explicitly
> designed to also support RTCP feedback in SSM environments--obviously
> at some loss of damping efficiency but what would you expect if you
> double propagation delay.

I was saying:
> Thanks, Colin,
> 
> Just as a general critique: I don't think that a draft like
> draft-ietf-avt-rtcp-feedback should go forward without specifically
> detailing whether or how it supports ASM and/or SSM multicast. This draft
> only refers to multicast, and that is just not sufficient anymore.

eg: different draft! But one which i think relates quite a bit to the
issue at hand as well and should not become an RFC without explicitly
mentioning ASM and SSM (which it does not).

I for once fail to easily determine from the claims of support whether
one could use the mechanisms described therein with SSM (i think not),
nor do i understand easily whether it would be possible to use them with
SSM if combined with draft-ietf-avt-rtcpssm without further extensions.

And this is probably not the only draft about other RTCP stuff. For
all of it, the rule applies: In the real world, customers want to move
to SSM and it needs to be easy to determine applicability  from the
drafts claims !

Cheers
	Toerless

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