Re: [MMUSIC] Feedback requested on requirements

worley@ariadne.com (Dale R. Worley) Thu, 25 April 2013 19:34 UTC

Return-Path: <worley@shell01.TheWorld.com>
X-Original-To: mmusic@ietfa.amsl.com
Delivered-To: mmusic@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 5E4AE21F96C5 for <mmusic@ietfa.amsl.com>; Thu, 25 Apr 2013 12:34:03 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.86
X-Spam-Level:
X-Spam-Status: No, score=-2.86 tagged_above=-999 required=5 tests=[AWL=0.120, BAYES_00=-2.599, RCVD_IN_DNSWL_LOW=-1, RCVD_IN_SORBS_WEB=0.619]
Received: from mail.ietf.org ([12.22.58.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id X055LnkyYbuU for <mmusic@ietfa.amsl.com>; Thu, 25 Apr 2013 12:34:02 -0700 (PDT)
Received: from TheWorld.com (pcls6.std.com [192.74.137.146]) by ietfa.amsl.com (Postfix) with ESMTP id 157FA21F9647 for <mmusic@ietf.org>; Thu, 25 Apr 2013 12:34:01 -0700 (PDT)
Received: from shell.TheWorld.com (root@shell01.theworld.com [192.74.137.71]) by TheWorld.com (8.14.5/8.14.5) with ESMTP id r3PJX3KP006525; Thu, 25 Apr 2013 15:33:05 -0400
Received: from shell01.TheWorld.com (localhost.theworld.com [127.0.0.1]) by shell.TheWorld.com (8.13.6/8.12.8) with ESMTP id r3PJX34d3436818; Thu, 25 Apr 2013 15:33:03 -0400 (EDT)
Received: (from worley@localhost) by shell01.TheWorld.com (8.13.6/8.13.6/Submit) id r3PJX2Lk3440743; Thu, 25 Apr 2013 15:33:02 -0400 (EDT)
Date: Thu, 25 Apr 2013 15:33:02 -0400
Message-Id: <201304251933.r3PJX2Lk3440743@shell01.TheWorld.com>
From: worley@ariadne.com
Sender: worley@ariadne.com
To: Paul Kyzivat <pkyzivat@alum.mit.edu>
In-reply-to: <51786396.9080706@alum.mit.edu> (pkyzivat@alum.mit.edu)
References: <201304231530.r3NFU9mB3237170@shell01.TheWorld.com> <7594FB04B1934943A5C02806D1A2204B1C35BC40@ESESSMB209.ericsson.se> <201304231935.r3NJZ24T3171577@shell01.TheWorld.com> <51786396.9080706@alum.mit.edu>
Cc: mmusic@ietf.org
Subject: Re: [MMUSIC] Feedback requested on requirements
X-BeenThere: mmusic@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Multiparty Multimedia Session Control Working Group <mmusic.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/mmusic>, <mailto:mmusic-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/mmusic>
List-Post: <mailto:mmusic@ietf.org>
List-Help: <mailto:mmusic-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/mmusic>, <mailto:mmusic-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 25 Apr 2013 19:34:03 -0000

> From: Paul Kyzivat <pkyzivat@alum.mit.edu>

> >>>    DES C4  Any additional m= lines prescribed by the bundle mechanism
> >>>       should be ordered after the constituent m= lines.

> > If a "bundle" media description is to be added, it ought to be added
> > *after* the m= lines for the constituent media streams, so that the
> > "bundle" media description doesn't change which media description is
> > identified as "the first audio media description", "the second audio
> > media description", "the first video media description", etc.
> 
> So, suppose A makes an offer to B with 4 m-lines to be bundled, with a 
> 5th "bundle" m-line after those.
> 
> But then suppose B needs those split into two bundles with different 
> addresses.
> 
> B could accept the initial offer but reject m-lines 2 & 4. So then there 
> is a bundle consisting of m-lines 1,3,5.
> 
> Then it might send another offer back toward A, reactivating m-lines 2 & 
> 4, and adding m-line 6 as the bundle m-line for the second bundle. 
> Assuming A accepts that, then there will be two bundles, 1,3,5 and 2,4,6.
> 
> Is that consistent with what you are proposing here?

Yes, that seems consistent with this desideratum.  The "bundle" m=
lines are 5 (containing 1 and 3) and 6 (containing 2 and 4), and each
of them follows all of the constituent m= lines.  That makes it less
likely that a simple-minded UA considers m= lines 5 and 6 to be usable
media.

In this particular case, B might want to accept 2 and 4, but
disconnect them from the bundle (now containing 1 and 3 only).  Then B
could send a new offer bundling 2 and 4 separately.  That prevents an
interval during which 2 and 4 are inactive, which might not be the
semantics B wants to present to A.

Dale