[Roll] I-D Action: draft-ietf-roll-minrank-hysteresis-of-10 Comments

Federico Consoli <admin@ipv6it.org> Sun, 13 May 2012 14:02 UTC

Return-Path: <admin@ipv6it.org>
X-Original-To: roll@ietfa.amsl.com
Delivered-To: roll@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 2FD7B21F858E for <roll@ietfa.amsl.com>; Sun, 13 May 2012 07:02:07 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.185
X-Spam-Level:
X-Spam-Status: No, score=-1.185 tagged_above=-999 required=5 tests=[BAYES_40=-0.185, RCVD_IN_DNSWL_LOW=-1]
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 dncctnRMzoIB for <roll@ietfa.amsl.com>; Sun, 13 May 2012 07:02:06 -0700 (PDT)
Received: from mail-bk0-f44.google.com (mail-bk0-f44.google.com [209.85.214.44]) by ietfa.amsl.com (Postfix) with ESMTP id 13B1521F8499 for <Roll@ietf.org>; Sun, 13 May 2012 07:02:05 -0700 (PDT)
Received: by bkty8 with SMTP id y8so3720416bkt.31 for <Roll@ietf.org>; Sun, 13 May 2012 07:02:05 -0700 (PDT)
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:cc:subject :content-type:content-transfer-encoding:x-gm-message-state; bh=DFhRvjqCOtqKaBc/xFgucCn5jufKH+rzabNFmmhBdE4=; b=SX48JiFJ1kMuc64h+hcGvj0qHBDxHfNTpJsrG8NHLHExOmtgDWt0JyFYhVig3s8O88 0F8OXa+jrdnE69Jm078mF0BAyKDr837AKlWWzDW2z4uo5traBSDbQjobQKJhryMuMbsI lHaq02Yo3ZnnoNQ4DSll+jLAzljVd/h6kkFs0q6jDMCt8dEEa/1wmRdxzzSqmRcDsS2z IqEWFmOO4+phjYNeNU3XnEjpRwDbJqANt/R1DSphGTBcFtCo2iMvRiCkKxg1FMcWUZuw RB5zWsKyr4mO3LId8H5uZXPD3vvUlWjfUc9jhGeRYzsp1lBOtpYie8mTclXRn/PxJKq4 QNcw==
Received: by 10.205.118.9 with SMTP id fo9mr1791359bkc.58.1336917724984; Sun, 13 May 2012 07:02:04 -0700 (PDT)
Received: from [127.0.0.1] ([87.18.133.188]) by mx.google.com with ESMTPS id fw10sm28624363bkc.11.2012.05.13.07.02.02 (version=SSLv3 cipher=OTHER); Sun, 13 May 2012 07:02:04 -0700 (PDT)
Message-ID: <4FAFBED7.4060207@ipv6it.org>
Date: Sun, 13 May 2012 16:01:59 +0200
From: Federico Consoli <admin@ipv6it.org>
User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:12.0) Gecko/20120428 Thunderbird/12.0.1
MIME-Version: 1.0
To: Roll@ietf.org
Content-Type: text/plain; charset=ISO-8859-15; format=flowed
Content-Transfer-Encoding: 7bit
X-Gm-Message-State: ALoCoQlu3mDAIxzTPSYzLKAx60FhwXkzlrJurwYaXj+C3t5ZKo1M3vIcwKC93tCJuFLGUCbynogS
Subject: [Roll] I-D Action: draft-ietf-roll-minrank-hysteresis-of-10 Comments
X-BeenThere: roll@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Routing Over Low power and Lossy networks <roll.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/roll>, <mailto:roll-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/roll>
List-Post: <mailto:roll@ietf.org>
List-Help: <mailto:roll-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/roll>, <mailto:roll-request@ietf.org?subject=subscribe>
X-List-Received-Date: Sun, 13 May 2012 14:02:07 -0000

Hi,
I have a doubt concerning the selection of parent set.
Draft Section 3.3 says:
"The exact selection of a parent set is an implementation decision."

The document does not specify what to do in a situation like this:

Example:
------
The node A has 1 parent with rank 700 and path cost 300 => A has a rank 
= 1000.
B has A as Preferred parent and the path cost A-B is 300, soB has rank 1300.

Later A receives from node C a DIO. Node C has rank 900 andpath cost A-C 
is 500 => A puts C in its parent set and announce a rank 1400.
But, A receives a DIO from node B before to send a DIO =>A puts B in its 
parent set.

When B receives the DD it will increase its rank. When Node A receives 
the DIO from the node B, it has 2 options:
1) Increase its rank
2) Delete the node from the parent set

If A chooses option 1 there will be an infinite loop.
------

In general, a node does not know the reason why a parent increase its 
rank. In fact, a node can also increase his rank because its link is got 
worse.

IMHO I think that if a parent announces a rank higher than the rank of 
the the nodethen the node MUST remove the parent from its Parent set.

-- 
Regards
Consoli Federico