Re: [trill] Any comments on Coordinated Multicast Trees (CMT) for TRILL - draft-ietf-trill-cmt-00

Ayan Banerjee <ayabaner@gmail.com> Fri, 17 August 2012 05:27 UTC

Return-Path: <ayabaner@gmail.com>
X-Original-To: trill@ietfa.amsl.com
Delivered-To: trill@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 723F221F8462; Thu, 16 Aug 2012 22:27:08 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.373
X-Spam-Level:
X-Spam-Status: No, score=-2.373 tagged_above=-999 required=5 tests=[AWL=-1.224, BAYES_00=-2.599, MIME_CHARSET_FARAWAY=2.45, RCVD_IN_DNSWL_LOW=-1]
Received: from mail.ietf.org ([64.170.98.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id ze2VbHHSGblp; Thu, 16 Aug 2012 22:27:07 -0700 (PDT)
Received: from mail-we0-f172.google.com (mail-we0-f172.google.com [74.125.82.172]) by ietfa.amsl.com (Postfix) with ESMTP id 78C8921F8452; Thu, 16 Aug 2012 22:27:07 -0700 (PDT)
Received: by weyu54 with SMTP id u54so2524852wey.31 for <multiple recipients>; Thu, 16 Aug 2012 22:27:06 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; bh=mzH1f+Jcy9SrM1f2bL7VA5A0Akt5Ihua5RZfLcbKoVg=; b=sLfRjA+egMs9cKJbhhjn6GdPz9uDaf6DxSMD3PNtd/t4S883Hw8FfFrvjEISke+177 pFSv5j5Ra7P3Qs4+cg0NtRMANfqqrgwYQQ090UDn/5R2g4whPodp7IG+kUGvJBJWhPaK +5oy5wgci643jji8MYc/CzsWLAwaR7IPrjVxEbzPx8+/QEY3d3UMpPhT20WxiseI7Zd+ jLCA/ljMIUUbmgogoUSGlNx6B7+3/2aosFmOPqESiKLCyQLbKEx4M0iOTL9opqxDHD6N 7PuLSm4UU4NXq3sHeGnJ36yvKvq9jydOBEZ3pDLx8J7+aReXB2A9Gc53P2sK6jKaKvmz iEkw==
MIME-Version: 1.0
Received: by 10.216.135.147 with SMTP id u19mr1895579wei.12.1345181226272; Thu, 16 Aug 2012 22:27:06 -0700 (PDT)
Received: by 10.194.59.75 with HTTP; Thu, 16 Aug 2012 22:27:06 -0700 (PDT)
In-Reply-To: <OFAD84654D.B1E3EDC6-ON48257A5C.002E0F85-48257A5C.002FA5A0@zte.com.cn>
References: <502C1EA0.7050305@acm.org> <OFAD84654D.B1E3EDC6-ON48257A5C.002E0F85-48257A5C.002FA5A0@zte.com.cn>
Date: Thu, 16 Aug 2012 22:27:06 -0700
Message-ID: <CAHD03N8LvaCGO3ig+6sEUvXeW7F+qomEyDzXE1GbVEYoP5RSDg@mail.gmail.com>
From: Ayan Banerjee <ayabaner@gmail.com>
To: liao.ting@zte.com.cn
Content-Type: text/plain; charset=GB2312
Content-Transfer-Encoding: quoted-printable
Cc: Erik Nordmark <nordmark@acm.org>, trill-bounces@ietf.org, "trill@ietf.org" <trill@ietf.org>
Subject: Re: [trill] Any comments on Coordinated Multicast Trees (CMT) for TRILL - draft-ietf-trill-cmt-00
X-BeenThere: trill@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: "Developing a hybrid router/bridge." <trill.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/trill>, <mailto:trill-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/trill>
List-Post: <mailto:trill@ietf.org>
List-Help: <mailto:trill-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/trill>, <mailto:trill-request@ietf.org?subject=subscribe>
X-List-Received-Date: Fri, 17 Aug 2012 05:27:08 -0000

Liao,

Just to get the entire context of the Section that you quote from the RFC:

   How an ingress RBridge chooses the distribution tree or trees that it
   uses for multi-destination frames is beyond the scope of this
   document.  However, for the reasons stated above, in the absence of
   other factors, a good choice is the tree whose root is least cost
   from the ingress RBridge and that is the default for an ingress
   RBridge that uses a single tree to distribute multi-destination
   frames.


The RFC clearly states that it is outside its scope and has a
suggestion regarding root choice. This draft provides the "other
factors" to influence the choice of trees.

Thanks,
Ayan




On Thu, Aug 16, 2012 at 1:40 AM, <liao.ting@zte.com.cn> wrote:
>
>
> I have read this draft and have a question about section 5.1,
> it describes how to distribute the trees among edge RB members of a group as follow:
>      Assign each tree to RBi such that tree number { (tree_number) %
>      k}+1 is assigned to RBridge i for tree_number from 1 to n. where n
>      is the number of trees and k is the number of RBridges considered
>      for tree allocation.
>
> And in RFC 6325 section 4.5 describes:
>    a good choice is the tree whose root is least cost
>    from the ingress RBridge and that is the default for an ingress
>    RBridge that uses a single tree to distribute multi-destination
>    frames.
>
> So, if a network has two trees, the first tree root is RBi and the second tree root is RBj,
> a group has two member RBridges RB1 and RB2, numerically ascending order by SystemID such that RB1<RB2,
> RBi is assigned to RB1 and RBj is assigned to RB2 as described in this draft,
> but maybe RB1 is closer to RBj and RB2 is closer to RBi, does the solution care about this?
>
>
>
> Erik Nordmark <nordmark@acm.org>
> 发件人:  trill-bounces@ietf.org
>
> 2012-08-16 06:11
>
> 收件人
> "trill@ietf.org" <trill@ietf.org>
> 抄送
> 主题
> [trill] Any comments on Coordinated Multicast Trees (CMT) for TRILL        - draft-ietf-trill-cmt-00
>
>
>
>
>
>
> We are trying to understand if this document is getting close to WG last
> call, but we don't know how many have read the document.
>
> If you have reviewed the document, please let us know.
> If not, this might be a good time to review the document and provide
> comments.
>
> Thanks,
>    Erik and Donald
> _______________________________________________
> trill mailing list
> trill@ietf.org
> https://www.ietf.org/mailman/listinfo/trill
>
>
>
> _______________________________________________
> trill mailing list
> trill@ietf.org
> https://www.ietf.org/mailman/listinfo/trill
>