Re: [6lowpan] FW: TID in ARO [was: "Advertize on Behalf" flag in ARO]

"Pascal Thubert (pthubert)" <pthubert@cisco.com> Fri, 22 April 2011 07:30 UTC

Return-Path: <pthubert@cisco.com>
X-Original-To: 6lowpan@ietfc.amsl.com
Delivered-To: 6lowpan@ietfc.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfc.amsl.com (Postfix) with ESMTP id 1BB49E06A7 for <6lowpan@ietfc.amsl.com>; Fri, 22 Apr 2011 00:30:44 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -9.011
X-Spam-Level:
X-Spam-Status: No, score=-9.011 tagged_above=-999 required=5 tests=[AWL=1.588, BAYES_00=-2.599, RCVD_IN_DNSWL_HI=-8]
Received: from mail.ietf.org ([208.66.40.236]) by localhost (ietfc.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id CcAdoxV9M2Hm for <6lowpan@ietfc.amsl.com>; Fri, 22 Apr 2011 00:30:43 -0700 (PDT)
Received: from ams-iport-2.cisco.com (ams-iport-2.cisco.com [144.254.224.141]) by ietfc.amsl.com (Postfix) with ESMTP id 32771E0687 for <6lowpan@ietf.org>; Fri, 22 Apr 2011 00:30:43 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cisco.com; i=pthubert@cisco.com; l=1467; q=dns/txt; s=iport; t=1303457443; x=1304667043; h=mime-version:content-transfer-encoding:subject:date: message-id:in-reply-to:references:from:to:cc; bh=o9cohA0ZxEjEqb+J+jRVsaIu+0ERq+wUPamSDTj+PRU=; b=gs4uHxWQ6ddyjZUPMRGkaWI6KYA7Y2cgguOcImyk55CO3Jn9ryEv8umo wvzdIxHgXS2+1KwjI7EPxSPi9dQqQzyEZkzsmAgLN1LCXrCQ9g6v4HKk+ XPtLP3md7Nwe0wdlaV/b0K8yCeHnAaYAe+hPd8eHd6kWOBrF57j57HwNY U=;
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: AgcEAF4usU2Q/khLgWdsb2JhbAClXhQBARYmJaYJnF2FdgSSOw
X-IronPort-AV: E=Sophos;i="4.64,253,1301875200"; d="scan'208";a="26718010"
Received: from ams-core-2.cisco.com ([144.254.72.75]) by ams-iport-2.cisco.com with ESMTP; 22 Apr 2011 07:30:41 +0000
Received: from xbh-ams-101.cisco.com (xbh-ams-101.cisco.com [144.254.74.71]) by ams-core-2.cisco.com (8.14.3/8.14.3) with ESMTP id p3M7Uedw031791; Fri, 22 Apr 2011 07:30:40 GMT
Received: from xmb-ams-107.cisco.com ([144.254.74.82]) by xbh-ams-101.cisco.com with Microsoft SMTPSVC(6.0.3790.4675); Fri, 22 Apr 2011 09:30:40 +0200
X-MimeOLE: Produced By Microsoft Exchange V6.5
Content-class: urn:content-classes:message
MIME-Version: 1.0
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: quoted-printable
Date: Fri, 22 Apr 2011 09:30:37 +0200
Message-ID: <6A2A459175DABE4BB11DE2026AA50A5D0470FA25@XMB-AMS-107.cisco.com>
In-Reply-To: <4DB0A442.4010905@acm.org>
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
Thread-Topic: [6lowpan] FW: TID in ARO [was: "Advertize on Behalf" flag in ARO]
Thread-Index: AcwAbKrVoBRI44dBSdWftn+cgFdEKQAUWQqA
References: <OF0DBCBB23.FB5BBA7F-ONC1257879.004686FB-C1257879.004FB860@Schneider-Electric.com> <4DB0A442.4010905@acm.org>
From: "Pascal Thubert (pthubert)" <pthubert@cisco.com>
To: "Erik Nordmark" <nordmark@acm.org>, <nicolas.riou@schneider-electric.com>
X-OriginalArrivalTime: 22 Apr 2011 07:30:40.0569 (UTC) FILETIME=[2E7E6290:01CC00BF]
Cc: 6lowpan@ietf.org
Subject: Re: [6lowpan] FW: TID in ARO [was: "Advertize on Behalf" flag in ARO]
X-BeenThere: 6lowpan@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Working group discussion for IPv6 over LowPan networks <6lowpan.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/6lowpan>, <mailto:6lowpan-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/6lowpan>
List-Post: <mailto:6lowpan@ietf.org>
List-Help: <mailto:6lowpan-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/6lowpan>, <mailto:6lowpan-request@ietf.org?subject=subscribe>
X-List-Received-Date: Fri, 22 Apr 2011 07:30:44 -0000

Hello Nicolas, Erik,

> >
> > As Pascal answered in his post, the TID is not particularly coupled
> > with RPLv1. The TID is just an extra information provided by the
node
> > during ND registration which dramatically simplifies node
localization
> > but also enable DAD across a backbone of Edge Routers advertizing
the
> same prefix.
> > Which alternative solution would you suggest for DAD?
> 
> DAD works fine with what we have in ARO.
> If the same EUI-64 (re)registers the same IPv6 address, then it is not
a
> duplicate.
> If a different EUI-64 tries to registers an IPv6 address (already
registered with
> some other EUI-64), then it is a duplicate.
> That is independent whether the check is done in a 6LR or 6LBR.
> 
> What do you see as the problem with DAD? Can you provide an example of
> what doesn't work with 6lowpan-nd?

[Pascal] TID is not related to uniqueness/DAD. It is related to
movement. A node that stays attached to the same router would not need
it. Tragically, LLNs are not like that.
TID enables to invalidate states that have a deprecated sequence.
Typically if you want to redistribute an ND registration into something
else then you need such thing.

I listed in another post 3 issues with ND that can be fixed with a TID
(scalability, out-of-order, and anti-replay). DAD is not in the list. 
DAD works as long as the EUI is unique, which is an assumption we
accepted for this work.

Pascal