IETF Logo Mail Archive

RE: To DAD or not to DAD?

"Hemant Singh (shemant)" <shemant@cisco.com> Tue, 24 February 2015 15:49 UTC

Return-Path: <shemant@cisco.com>
X-Original-To: ipv6@ietfa.amsl.com
Delivered-To: ipv6@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id E10371A8824 for <ipv6@ietfa.amsl.com>; Tue, 24 Feb 2015 07:49:56 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -14.511
X-Spam-Level:
X-Spam-Status: No, score=-14.511 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_HI=-5, SPF_PASS=-0.001, T_RP_MATCHES_RCVD=-0.01, USER_IN_DEF_DKIM_WL=-7.5] autolearn=ham
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 L0fWafMrOW1r for <ipv6@ietfa.amsl.com>; Tue, 24 Feb 2015 07:49:55 -0800 (PST)
Received: from rcdn-iport-2.cisco.com (rcdn-iport-2.cisco.com [173.37.86.73]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id E47611A87EE for <6man@ietf.org>; Tue, 24 Feb 2015 07:49:54 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cisco.com; i=@cisco.com; l=2342; q=dns/txt; s=iport; t=1424792995; x=1426002595; h=from:to:subject:date:message-id:references:in-reply-to: content-transfer-encoding:mime-version; bh=LXTzTkQIMwnNO/iWy/EVcyKd9XUUYiU/HdFxaLbKTvM=; b=PAPhE+iwDB+JX4/oSiayC0+PzIgWPZQtqN6THsWRnYj8NG6BjXAsShFX 78HX5vVrxA3UGJp9lHU2nc7tihPhgSTlhdylTDWW1qk+31G3oigbpL6Wv uWnMIFc/caKBgwF491Jn74fGVADu9uxastzJkaMkH1+Pp7evtUBOyYWn7 U=;
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: A0CaBQBInexU/4YNJK1bgwZSWgTDEgqEYwGBDAKBJUMBAQEBAQF8hA8BAQECAgEBATc0FwQCAQgRBAEBCxQJBycLFAkIAgQBEggBiCYN1D0BAQEBAQEBAQEBAQEBAQEBAQEBAQEXixOEDBEBHzgGgxGBFAWFZIlyg2CZHCKCAhyBUG8BgQEFAgIXIn8BAQE
X-IronPort-AV: E=Sophos;i="5.09,639,1418083200"; d="scan'208";a="399052452"
Received: from alln-core-12.cisco.com ([173.36.13.134]) by rcdn-iport-2.cisco.com with ESMTP; 24 Feb 2015 15:49:38 +0000
Received: from xhc-rcd-x12.cisco.com (xhc-rcd-x12.cisco.com [173.37.183.86]) by alln-core-12.cisco.com (8.14.5/8.14.5) with ESMTP id t1OFncbF025369 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=FAIL); Tue, 24 Feb 2015 15:49:38 GMT
Received: from xmb-rcd-x06.cisco.com ([169.254.6.40]) by xhc-rcd-x12.cisco.com ([173.37.183.86]) with mapi id 14.03.0195.001; Tue, 24 Feb 2015 09:49:38 -0600
From: "Hemant Singh (shemant)" <shemant@cisco.com>
To: Erik Nordmark <nordmark@acm.org>, "6man@ietf.org" <6man@ietf.org>
Subject: RE: To DAD or not to DAD?
Thread-Topic: To DAD or not to DAD?
Thread-Index: AQHQS7OiTZZ4njkebUio2cP8BCSONpz/9NKw
Date: Tue, 24 Feb 2015 15:49:36 +0000
Message-ID: <75B6FA9F576969419E42BECB86CB1B8916809AF0@xmb-rcd-x06.cisco.com>
References: <54E4EC1A.3080303@acm.org>
In-Reply-To: <54E4EC1A.3080303@acm.org>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
x-originating-ip: [10.131.71.126]
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
Archived-At: <http://mailarchive.ietf.org/arch/msg/ipv6/7iazdxzEeCHGIpNiEcQ384mXHLA>
X-BeenThere: ipv6@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: "IPv6 Maintenance Working Group \(6man\)" <ipv6.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/ipv6>, <mailto:ipv6-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/ipv6/>
List-Post: <mailto:ipv6@ietf.org>
List-Help: <mailto:ipv6-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/ipv6>, <mailto:ipv6-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 24 Feb 2015 15:49:57 -0000

I'd go with option 3 and see which issues from draft-yourtchenko-6man-dad-issues could be addressed.   I already like what Erik has highlighted in bold for DAD issues in http://www.ietf.org/proceedings/91/slides/slides-91-6man-11.pdf.  The issues in bold are:

Behavior on links with unreliable multicast
Energy efficiency
Wake-up and L2 events

One adds complexity to the host to special-case using DAD for manually configured IPv6 address vs. a DHCPv6- or SLAAC- acquired address.  Also, as others have said, DAD is needed to detect duplicates in many networks.  

Regards,

Hemant 

-----Original Message-----
From: ipv6 [mailto:ipv6-bounces@ietf.org] On Behalf Of Erik Nordmark
Sent: Wednesday, February 18, 2015 2:47 PM
To: 6man@ietf.org
Subject: To DAD or not to DAD?


Hello,

Back in November the efficient-nd design team presented slides
(http://www.ietf.org/proceedings/91/slides/slides-91-6man-11.pdf)
and a document was produced on the DAD problems
(https://datatracker.ietf.org/doc/draft-yourtchenko-6man-dad-issues/)

The key questions in the design team report was what to do about DAD. 
But we haven't had any discussion on this on the list and I'd like to get some feedback from the WG to we can move forward.

The slides offered these options:
1. Deprecate DAD - it is expensive and duplicates are not common 2. Only send and receive DAD for manually configured addresses 3. Improve DAD
  3a. Better at detecting duplicates (partition-join, etc)
  3b. Less network and host impact (allow sleep schedule) 4. Do nothing a. aka go to the beach ;-)

The 3a vs. 3b implicitly refers to the list of issues in draft-yourtchenko-6man-dad-issues.

Given that the beach is kind of cold this time of year, we can remove the 4th choice from the list.
More seriously, the WG needs to decide how to move forward with DAD.

Would it be helpful to present draft-yourtchenko-6man-dad-issues in Dallas? Or can we have an email discussion without/prior to such a presentation?

Regards,
     Erik

--------------------------------------------------------------------
IETF IPv6 working group mailing list
ipv6@ietf.org
Administrative Requests: https://www.ietf.org/mailman/listinfo/ipv6
--------------------------------------------------------------------

v2.23.0 | Report a Bug | By Email