Re: [MMUSIC] New Draft: SDP Grouping Identifiers

Adam Roach <adam@nostrum.com> Tue, 03 December 2013 23:05 UTC

Return-Path: <adam@nostrum.com>
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 F36741AE1BC for <mmusic@ietfa.amsl.com>; Tue, 3 Dec 2013 15:05:37 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.036
X-Spam-Level:
X-Spam-Status: No, score=-1.036 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, HELO_MISMATCH_COM=0.553, HOST_MISMATCH_NET=0.311] 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 z2aaQO13taKD for <mmusic@ietfa.amsl.com>; Tue, 3 Dec 2013 15:05:37 -0800 (PST)
Received: from shaman.nostrum.com (nostrum-pt.tunnel.tserv2.fmt.ipv6.he.net [IPv6:2001:470:1f03:267::2]) by ietfa.amsl.com (Postfix) with ESMTP id 659351AE1CF for <mmusic@ietf.org>; Tue, 3 Dec 2013 15:05:25 -0800 (PST)
Received: from orochi.roach.at (99-152-145-110.lightspeed.dllstx.sbcglobal.net [99.152.145.110]) (authenticated bits=0) by shaman.nostrum.com (8.14.3/8.14.3) with ESMTP id rB3N5IQP042054 (version=TLSv1/SSLv3 cipher=DHE-RSA-CAMELLIA256-SHA bits=256 verify=NO); Tue, 3 Dec 2013 17:05:18 -0600 (CST) (envelope-from adam@nostrum.com)
Message-ID: <529E63A9.9090302@nostrum.com>
Date: Tue, 03 Dec 2013 17:05:13 -0600
From: Adam Roach <adam@nostrum.com>
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:24.0) Gecko/20100101 Thunderbird/24.1.1
MIME-Version: 1.0
To: Paul Kyzivat <pkyzivat@alum.mit.edu>, mmusic@ietf.org
References: <529DE6AF.1060300@nostrum.com> <529E129F.2080304@alum.mit.edu>
In-Reply-To: <529E129F.2080304@alum.mit.edu>
Content-Type: text/plain; charset="UTF-8"; format="flowed"
Content-Transfer-Encoding: 7bit
Received-SPF: pass (shaman.nostrum.com: 99.152.145.110 is authenticated by a trusted mechanism)
Subject: Re: [MMUSIC] New Draft: SDP Grouping Identifiers
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: <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: Tue, 03 Dec 2013 23:05:38 -0000

On 12/3/13 11:19, Paul Kyzivat wrote:
> Since group-ids are required to be unique within the session, why is 
> it necessary to include the group semantic in the in-group attribute. 
> IOW,
> why not:
>   a=in-group abc
> rather than
>   a=in-group LS:abc 

The idea behind the syntax here is that you can implicitly define a new 
group in a partial offer without having to include any session-level 
attributes. I'll admit that there are other ways to address this 
capability, but this is the one I prefer.

/a