Re: [MMUSIC] Offer/Answer PT Questions - text proposal

Paul Kyzivat <pkyzivat@alum.mit.edu> Tue, 01 March 2016 19:06 UTC

Return-Path: <pkyzivat@alum.mit.edu>
X-Original-To: mmusic@ietfa.amsl.com
Delivered-To: mmusic@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id B9AD41B3FF0 for <mmusic@ietfa.amsl.com>; Tue, 1 Mar 2016 11:06:12 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -0.635
X-Spam-Level:
X-Spam-Status: No, score=-0.635 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, J_CHICKENPOX_110=0.6, SPF_SOFTFAIL=0.665] autolearn=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id luf1856D2hOw for <mmusic@ietfa.amsl.com>; Tue, 1 Mar 2016 11:06:12 -0800 (PST)
Received: from resqmta-po-06v.sys.comcast.net (resqmta-po-06v.sys.comcast.net [IPv6:2001:558:fe16:19:96:114:154:165]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id DDA651B3FF6 for <mmusic@ietf.org>; Tue, 1 Mar 2016 11:06:10 -0800 (PST)
Received: from resomta-po-13v.sys.comcast.net ([96.114.154.237]) by resqmta-po-06v.sys.comcast.net with comcast id Qj5X1s00357bBgG01j6A1a; Tue, 01 Mar 2016 19:06:10 +0000
Received: from Paul-Kyzivats-MacBook-Pro.local ([73.218.51.154]) by resomta-po-13v.sys.comcast.net with comcast id Qj691s0053KdFy101j69Gy; Tue, 01 Mar 2016 19:06:10 +0000
To: Roman Shpount <roman@telurix.com>
References: <7594FB04B1934943A5C02806D1A2204B37E425AB@ESESSMB209.ericsson.se> <56D08962.3060006@alum.mit.edu> <CAD5OKxtRB-f84=axhq_mkuyGXcq8nLCU2T6+6y=DNv9Ng1tKPQ@mail.gmail.com> <56D09563.9040509@alum.mit.edu> <CAD5OKxvwJwKoaaMHDDA8AKYdd2Rc8vOK_dnOftvozX+FbfqHOQ@mail.gmail.com> <56D1CA6C.70700@alum.mit.edu> <CAD5OKxt5jp44Saop+ssdPENBsRBNbkFUXFphZHMwqYDFLNWFpg@mail.gmail.com> <7594FB04B1934943A5C02806D1A2204B37E4BD38@ESESSMB209.ericsson.se> <56D463A3.8070007@alum.mit.edu> <7594FB04B1934943A5C02806D1A2204B37E4D5E9@ESESSMB209.ericsson.se> <56D4B1F1.2070706@alum.mit.edu> <7594FB04B1934943A5C02806D1A2204B37E4D951@ESESSMB209.ericsson.se> <66F2264B-3CA3-4650-88B6-89FC64D5FD29@csperkins.org> <7594FB04B1934943A5C02806D1A2204B37E4DB7C@ESESSMB209.ericsson.se> <56D4C0F5.50901@alum.mit.edu> <7594FB04B1934943A5C02806D1A2204B37E4EAD1@ESESSMB209.ericsson.se> <56D5CAA0.2060901@alum.mit.edu> <CAD5OKxtdmhW-opmp2TQou5wYbz70FdUvftr1PAZb9YiW4crevA@mail.gmail.com>
From: Paul Kyzivat <pkyzivat@alum.mit.edu>
Message-ID: <56D5E81F.2040306@alum.mit.edu>
Date: Tue, 01 Mar 2016 14:06:07 -0500
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:38.0) Gecko/20100101 Thunderbird/38.6.0
MIME-Version: 1.0
In-Reply-To: <CAD5OKxtdmhW-opmp2TQou5wYbz70FdUvftr1PAZb9YiW4crevA@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"; format="flowed"
Content-Transfer-Encoding: 7bit
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=comcast.net; s=q20140121; t=1456859170; bh=MTklY5FH0rajWogek7J+GE4ujQTt59Hx2K1n+JEFq4w=; h=Received:Received:Subject:To:From:Message-ID:Date:MIME-Version: Content-Type; b=eQLpypQBrJWEm0etWyM6HSs6XJIxQy3DSeBArXlEQPJJ20lOuWZaTuazz45z1ayoA gxJv+MURXPgzBoYKyl6bUZtq7yg8YwKgf4X/JKbELa13FHPPZrkW+rY9uz4X/uxH3r efLSpOyBWd9t9sT5pbsBpFYT9r85S8JpydWs/Ei1SH0KLQbaVYEJ7U6Zew//Ji41De s9k16iSBMz4y/4r5vcM9mrMO5yXTumfAeYrob6rJoRQsa9zz+DZzFspBBCA1NT+VHq gxOqB6EUkbOqJ5f2ynUsq8ji2kpL1kZlNr3WMTZxHF/Ug3/qClwv0pFFgf0iaVHMap 2Ws6trGwH/gWg==
Archived-At: <http://mailarchive.ietf.org/arch/msg/mmusic/8V4fJuRuZBUYieoOhycUvFOxSrk>
Cc: "mmusic@ietf.org" <mmusic@ietf.org>, Colin Perkins <csp@csperkins.org>, Christer Holmberg <christer.holmberg@ericsson.com>
Subject: Re: [MMUSIC] Offer/Answer PT Questions - text proposal
X-BeenThere: mmusic@ietf.org
X-Mailman-Version: 2.1.15
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: <https://mailarchive.ietf.org/arch/browse/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: Tue, 01 Mar 2016 19:06:12 -0000

On 3/1/16 1:23 PM, Roman Shpount wrote:

> What really bugs me about this discussion is that it is extremely
> difficult to determine when RTP session is started or stopped based on
> O/A exchanges. Because of this it is difficult to determine when it is
> safe to reuse PT for something else just by looking at O/A.

Well, can we assume that if the addr/port changes at one of the ends 
then this is to be a new RTP session?

Are there cases where nothing in the SDP changes but a new RTP session 
is established? (Or can we require signaling in this case?)

Maybe we need to start using the a=connection attribute with RTP to 
indicate change of RTP session. :-)

	Thanks,
	Paul