Re: [MMUSIC] RFC 6190 Single Session Transport

Bernard Aboba <bernard_aboba@hotmail.com> Fri, 19 July 2013 02:02 UTC

Return-Path: <bernard_aboba@hotmail.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 7A5B921E8135 for <mmusic@ietfa.amsl.com>; Thu, 18 Jul 2013 19:02:27 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -102.541
X-Spam-Level:
X-Spam-Status: No, score=-102.541 tagged_above=-999 required=5 tests=[AWL=0.057, BAYES_00=-2.599, HTML_MESSAGE=0.001, USER_IN_WHITELIST=-100]
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 WBh4R9hJyG3M for <mmusic@ietfa.amsl.com>; Thu, 18 Jul 2013 19:02:21 -0700 (PDT)
Received: from blu0-omc1-s35.blu0.hotmail.com (blu0-omc1-s35.blu0.hotmail.com [65.55.116.46]) by ietfa.amsl.com (Postfix) with ESMTP id 70C6E21E8142 for <mmusic@ietf.org>; Thu, 18 Jul 2013 19:02:17 -0700 (PDT)
Received: from BLU169-W120 ([65.55.116.9]) by blu0-omc1-s35.blu0.hotmail.com with Microsoft SMTPSVC(6.0.3790.4675); Thu, 18 Jul 2013 19:02:17 -0700
X-TMN: [f8qLVuQU30gOGk6DxGoPqg7lRkTC/MSY33VcXZLSAQw=]
X-Originating-Email: [bernard_aboba@hotmail.com]
Message-ID: <BLU169-W1208949649FACAC3137B05C93630@phx.gbl>
Content-Type: multipart/alternative; boundary="_d703b482-bd81-4fe3-ade3-83c8931f1022_"
From: Bernard Aboba <bernard_aboba@hotmail.com>
To: Jonathan Lennox <jonathan@vidyo.com>
Date: Thu, 18 Jul 2013 19:02:16 -0700
Importance: Normal
In-Reply-To: <EE556E46-54C1-4AAB-B03A-56FB8971D8A2@vidyo.com>
References: <BLU169-W630D4FBAA70899F6C54A0593830@phx.gbl>, <3879D71E758A7E4AA99A35DD8D41D3D91D487E63@xmb-rcd-x14.cisco.com>, <EE556E46-54C1-4AAB-B03A-56FB8971D8A2@vidyo.com>
MIME-Version: 1.0
X-OriginalArrivalTime: 19 Jul 2013 02:02:17.0216 (UTC) FILETIME=[FEB29000:01CE8423]
Cc: "mmusic@ietf.org" <mmusic@ietf.org>
Subject: Re: [MMUSIC] RFC 6190 Single Session Transport
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: Fri, 19 Jul 2013 02:02:27 -0000

Jonathan said: 

"I don't understand how single-session multi-source transmission will work without either a) signaling "a=ssrc-group DDP" decoding dependencies, or b) making various implementation-specific assumptions about the structure of the SVC streams."
 
[BA] In terms of SDP choices for expressing layering within a single m line, you can either go the a=ssrc-group:DDP route, or use distinct payload types for each layer and RFC 5583 a=group:DDP (this is what "Unified Plan" Section 4.7 appears to advocate).  

I'm not sure how "MST within a single session" could be expressed in SDP without BUNDLE.  Was the idea to use multiple m lines and group them together but use the same port?