Return-Path: 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 AD74B21F8644 for ; Fri, 26 Oct 2012 09:11:04 -0700 (PDT) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -4.122 X-Spam-Level: X-Spam-Status: No, score=-4.122 tagged_above=-999 required=5 tests=[AWL=-0.524, BAYES_00=-2.599, HTML_MESSAGE=0.001, 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 nlFEuCLUeysN for ; Fri, 26 Oct 2012 09:11:03 -0700 (PDT) Received: from va3outboundpool.messaging.microsoft.com (va3ehsobe001.messaging.microsoft.com [216.32.180.11]) by ietfa.amsl.com (Postfix) with ESMTP id 847DF21F8633 for ; Fri, 26 Oct 2012 09:11:03 -0700 (PDT) Received: from mail177-va3-R.bigfish.com (10.7.14.243) by VA3EHSOBE014.bigfish.com (10.7.40.64) with Microsoft SMTP Server id 14.1.225.23; Fri, 26 Oct 2012 16:11:03 +0000 Received: from mail177-va3 (localhost [127.0.0.1]) by mail177-va3-R.bigfish.com (Postfix) with ESMTP id E8E7C2C01EA; Fri, 26 Oct 2012 16:11:02 +0000 (UTC) X-Forefront-Antispam-Report: CIP:157.56.252.165; KIP:(null); UIP:(null); IPV:NLI; H:DBXPRD0510HT001.eurprd05.prod.outlook.com; RD:none; EFVD:NLI X-SpamScore: -27 X-BigFish: VPS-27(zzbb2dI98dI9371Ic89bhc85dh1418Izz1202h1d1ah1d2ahzz1033IL17326ah8275bh8275dh5eeeKz2dh2a8h668h839hd25hf0ah1288h12a5h12bdh137ah1441h1504h1537h153bh1155h) Received: from mail177-va3 (localhost.localdomain [127.0.0.1]) by mail177-va3 (MessageSwitch) id 1351267859536579_21512; Fri, 26 Oct 2012 16:10:59 +0000 (UTC) Received: from VA3EHSMHS016.bigfish.com (unknown [10.7.14.237]) by mail177-va3.bigfish.com (Postfix) with ESMTP id 7EEC92A00C2; Fri, 26 Oct 2012 16:10:59 +0000 (UTC) Received: from DBXPRD0510HT001.eurprd05.prod.outlook.com (157.56.252.165) by VA3EHSMHS016.bigfish.com (10.7.99.26) with Microsoft SMTP Server (TLS) id 14.1.225.23; Fri, 26 Oct 2012 16:10:58 +0000 Received: from DBXPRD0510MB395.eurprd05.prod.outlook.com ([169.254.7.174]) by DBXPRD0510HT001.eurprd05.prod.outlook.com ([10.255.67.164]) with mapi id 14.16.0224.004; Fri, 26 Oct 2012 16:10:55 +0000 From: C Chauvenet To: Jianlin Guo Thread-Topic: [Roll] Loop free local DODAG repair solution Thread-Index: AQHNsShZPcx+lZkhlUaljQOJ54dOTZfJ8H+AgAAfrgCAACMDgIABZecAgAAfwYCAAAQ/gIAACYsA Date: Fri, 26 Oct 2012 16:10:55 +0000 Message-ID: <97B69B30E0EF244B940B65EA541E3F2D215676A7@DBXPRD0510MB395.eurprd05.prod.outlook.com> References: <50194329.3040003@merl.com> <501945CC.5040801@merl.com> <5086A598.7030508@merl.com> <23378.1351166893@sandelman.ca> <50894640.1080804@merl.com> <97B69B30E0EF244B940B65EA541E3F2D21564932@DBXPRD0510MB395.eurprd05.prod.outlook.com> <508A8FDA.4040104@merl.com> <97B69B30E0EF244B940B65EA541E3F2D2156744D@DBXPRD0510MB395.eurprd05.prod.outlook.com> <508AAE0D.8030903@merl.com> In-Reply-To: <508AAE0D.8030903@merl.com> Accept-Language: fr-FR, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.255.67.132] Content-Type: multipart/alternative; boundary="_000_97B69B30E0EF244B940B65EA541E3F2D215676A7DBXPRD0510MB395_" MIME-Version: 1.0 X-OriginatorOrg: watteco.com Cc: "" Subject: Re: [Roll] Loop free local DODAG repair solution X-BeenThere: roll@ietf.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Routing Over Low power and Lossy networks List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 26 Oct 2012 16:11:04 -0000 --_000_97B69B30E0EF244B940B65EA541E3F2D215676A7DBXPRD0510MB395_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Le 26 oct. 2012 =E0 17:36, Jianlin Guo a =E9crit : We compared performance metrics such as packet delivery rate. Ok. In general do you have a document about your experiments that you would lik= e to share ? I think it could be a good way to defend your mechanism. There are 2 sub questions related to your draft : - Is there a strong need for an additional mechanism to prevent loops ? (t= he HbH header option mentioned by phil is already there). - Is your mechanism the good way to do so (overhead induced, efficiency...= ) As mentioned by Phil, this subject has been previously discussed inside ROL= L few years ago, and did not recommend to add such mechanisms. For instance, [1] concludes that "the turmoil caused by dismantling of the sub-DAGs in order to increase ranks may be much more than what the routing loops themselves will cause. Consequently, the use of such loop avoidance mechanism in the operation of a DAG based routing protocol can not be universally recommended." [1] : http://www.emmanuelbaccelli.org/publications/AINA_2010.pdf Best, C=E9dric. On 10/26/2012 11:21 AM, C Chauvenet wrote: Hi, Thank you for your answer. See inline. Le 26 oct. 2012 =E0 15:27, Jianlin Guo a =E9crit : On 10/25/2012 12:06 PM, C Chauvenet wrote: Hi, Le 25 oct. 2012 =E0 16:01, Jianlin Guo a =E9crit : Hi Michael, For your first question, draft-clausen-lln-rpl-experiences-04 pointed out t= hat "it can be observed that with current implementations of RPL, such as t= he ContikiRPL implementation, loops do occur - and, frequently. During the = same experiments described in Section 13, a snapshot of the DODAG was made = every ten seconds. In 74.14% of the 4114 snapshots, at least one loop was o= bserved". Is it something that you observed in your own deployments ? More specifically : did you find similar results ? We observed the occurrence of loops, unfortunately we did not measure the p= ercentage. So how did you evaluate the benefit of the mechanism that you proposed ? C=E9dric. Best, C=E9dric. For your second question, further investigation and experiments are needed. Jianlin On 10/25/2012 8:08 AM, Michael Richardson wrote: Jianlin Guo wrote: JG> Dear ROLL WG members, JG> As we all know that loop is an open issue in RPL. Experiment shows = that loop JG> occurs quite often. We have proposed a loop free local DODAG Can you quantify "quite often"? Do you have any metrics for how often loops occur, and what the cost is of their repair? I think that the WG would be very very very interested in additional -exper= iences draft, or pointers to papers explaining same, that gives a repeateable experiment in which loops are observed. _______________________________________________ Roll mailing list Roll@ietf.org https://www.ietf.org/mailman/listinfo/roll --_000_97B69B30E0EF244B940B65EA541E3F2D215676A7DBXPRD0510MB395_ Content-Type: text/html; charset="iso-8859-1" Content-ID: <56BD524C0062204295B0EC9023192EB0@eurprd05.prod.outlook.com> Content-Transfer-Encoding: quoted-printable
Le 26 oct. 2012 =E0 17:36, Jianlin Guo a =E9crit :

We compared performance metrics such as pack= et delivery rate.

Ok.

In general do you have a document about your experiments that you woul= d like to share ?
I think it could be a good way to defend your mechanism.

There are 2 sub questions related to your draft : 

 - Is there a strong need for an additional mechanism to prevent = loops ? (the HbH header option mentioned by phil is already there).
 - Is your mechanism the good way to do so (overhead induced, eff= iciency...)

As mentioned by Phil, this subject has been previously discussed insid= e ROLL few years ago, and did not recommend to add such mechanisms.

For instance, [1] concludes that 

"the turmoil caused
by dismantling of the sub-DAGs in order to increase ranks
may be much more than what the routing loops themselves
will cause. Consequently, the use of such loop avoidance
mechanism in the operation of a DAG based routing protocol
can not be universally recommended."

[1] : http://www.emmanuelbaccelli.org/publications/AINA_2010.pdf<= /div>

Best,

C=E9dric.

On 10/26/2012 11:21 AM, C Chauvenet wrote:
Hi,
Thank you for your answer.
See inline.

Le 26 oct. 2012 =E0 15:27, Jianlin Guo a =E9crit :

On 10/25/2012 12:06 PM, C Chauvenet wrote:
Hi, 

Le 25 oct. 2012 =E0 16:01, Jianlin Guo a =E9crit :

Hi Michael,

For your first question, draft-clausen-lln-rpl-experiences-04 pointed out t= hat "it can be observed that with current implementations of RPL, such= as the ContikiRPL implementation, loops do occur - and, frequently. During the same experiments described in Section 13,= a snapshot of the DODAG was made every ten seconds. In 74.14% of the 4114 snapshots, at least one loop was observed&quo= t;.

Is it something that you observed in your own deployments ?
More specifically : did you find similar results ?
We observed the occurrence of loops, unfortunately we did not measure the p= ercentage.

So how did you evaluate the benefit of the mechanism that you proposed= ?

C=E9dric.


Best,

C=E9dric.


For your second question, further investigation and experiments are needed.=

Jianlin

On 10/25/2012 8:08 AM, Michael Richardson wrote:
Jianlin Guo <guo@merl.com> wrote:
    JG> Dear ROLL WG members,

    JG> As we all know that loop is an open issue in RPL. Experiment sho=
ws that loop
    JG> occurs quite often. We have proposed a loop free local DODAG

Can you quantify "quite often"?
Do you have any metrics for how often loops occur, and what the cost is
of their repair?

I think that the WG would be very very very interested in additional -exper=
iences
draft, or pointers to papers explaining same, that gives a repeateable
experiment in which loops are observed.

_______________________________________________
Roll mailing list
Roll@ietf.org=
https://www.ietf.org/mailman/listinfo/= roll





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