Re: [v6ops] PMTUD issue discussion

Owen DeLong <owen@delong.com> Fri, 05 September 2014 18:55 UTC

Return-Path: <owen@delong.com>
X-Original-To: v6ops@ietfa.amsl.com
Delivered-To: v6ops@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 049C81A6F51 for <v6ops@ietfa.amsl.com>; Fri, 5 Sep 2014 11:55:53 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.659
X-Spam-Level:
X-Spam-Status: No, score=-1.659 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_ADSP_ALL=0.8, DKIM_SIGNED=0.1, RP_MATCHES_RCVD=-0.668, SPF_PASS=-0.001, T_DKIM_INVALID=0.01] autolearn=no
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 YcZnOG8ceTw1 for <v6ops@ietfa.amsl.com>; Fri, 5 Sep 2014 11:55:52 -0700 (PDT)
Received: from owen.delong.com (owen.delong.com [IPv6:2620:0:930::200:2]) by ietfa.amsl.com (Postfix) with ESMTP id 4A15E1A014E for <v6ops@ietf.org>; Fri, 5 Sep 2014 11:55:51 -0700 (PDT)
Received: from [10.20.0.186] ([192.31.187.123]) (authenticated bits=0) by owen.delong.com (8.14.2/8.14.2) with ESMTP id s85IoNx6030154 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NOT); Fri, 5 Sep 2014 11:50:34 -0700
X-DKIM: Sendmail DKIM Filter v2.8.3 owen.delong.com s85IoNx6030154
DKIM-Signature: v=1; a=rsa-sha1; c=simple/simple; d=delong.com; s=mail; t=1409943036; bh=U74iFoaLNvSJdXh9wThg/4BQV+w=; h=Content-Type:Mime-Version:Subject:From:In-Reply-To:Date:Cc: Content-Transfer-Encoding:Message-Id:References:To; b=LbT0Tt9xLISRyRw5RUtngs6QTpDZXkDhTG+0LuOedhlmOU5XOxDovvQf0kwj6YpdC x/TtdAh0DCgjALf9NtAtHMBtHHQmvOD6ph46NSjtzNDcvnoyVBSQp2hcDD9kUXa5jr 2qRjIiigV7B2dFXfmubqaCpgEjxVsngBagWxMYGg=
Content-Type: text/plain; charset="windows-1252"
Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\))
From: Owen DeLong <owen@delong.com>
In-Reply-To: <5409C1D2.60604@isi.edu>
Date: Fri, 05 Sep 2014 11:50:19 -0700
Content-Transfer-Encoding: quoted-printable
Message-Id: <19AC0386-C63B-4B41-B303-FAA6C1B1C9D9@delong.com>
References: <0D370E74-688B-4EB3-A691-309A03AF20BA@cisco.com> <53FBA174.2040302@isi.edu> <53FBA6E1.90905@bogus.com> <CAPi140PMeM9omtm11+NHa2ywUfof_tE7HknKExtoEb32mm7L_w@mail.gmail.com> <71D0D5E8-80E9-430B-8ED4-16C1F99082CC@cisco.com> <54020ECC.4000000@globis.net> <CAEmG1=redpYUnv9R-uf+cJ4e+iPCf6zMHzVxeKNMGjcC=BjR+Q@mail.gmail.com> <5402C26A.8060304@globis.net> <540626F6.1020103@scea.com> <60533790-9A16-44C8-8239-89AE2C6BD783@cisco.com> <5408F6C6.3030103@gont.com.ar> <080303C1-D09F-4987-B114-F0F5C8B44863@cisco.com> <5409080E.7000200@si6networks.com> <9F0F552B-B465-40C4-8206-82A289294787@cisco.com> <5409C1D2.60604@isi.edu>
To: Joe Touch <touch@isi.edu>
X-Mailer: Apple Mail (2.1878.6)
Archived-At: http://mailarchive.ietf.org/arch/msg/v6ops/r0RuNG31HoyqJIwW-XbEYM130CQ
Cc: Fernando Gont <fgont@si6networks.com>, "v6ops@ietf.org" <v6ops@ietf.org>, Tom Perrine <tperrine@scea.com>, Fernando Gont <fernando@gont.com.ar>
Subject: Re: [v6ops] PMTUD issue discussion
X-BeenThere: v6ops@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: v6ops discussion list <v6ops.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/v6ops>, <mailto:v6ops-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/v6ops/>
List-Post: <mailto:v6ops@ietf.org>
List-Help: <mailto:v6ops-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/v6ops>, <mailto:v6ops-request@ietf.org?subject=subscribe>
X-List-Received-Date: Fri, 05 Sep 2014 18:55:53 -0000

On Sep 5, 2014, at 6:59 AM, Joe Touch <touch@isi.edu> wrote:

> 
> 
> On 9/4/2014 5:58 PM, Fred Baker (fred) wrote:
>> 
>> On Sep 5, 2014, at 10:47 AM, Fernando Gont <fgont@si6networks.com> wrote:
>> 
>>> On 09/04/2014 09:24 PM, Fred Baker (fred) wrote:
>>>> 
>>>> On Sep 5, 2014, at 9:33 AM, Fernando Gont <fernando@gont.com.ar>
>>>> wrote:
>>>> 
>>>>> What happens when/if such lins employ v6 (whether they really
>>>>> offer a "virtual" MTU >=1280).. I just don't know.
>>>> 
>>>> 802.15.4?
>>> 
>>> No. I seem to recall that it was more of a packet radio sort of thing
>>> (something predating 802.15.4). I could ask some folks if interested
>>> in more details…
>> 
>> I think you missed my point. We have a case in point today, which is
>> IPv6 in an IPv6 tunnel encapsulation running on a packet network whose
>> MTU is 127 bytes. We call it “6lowpan”, and it runs on IEEE 802.15.4.
> 
> That's not IPv6. I don't know what it is, but RFC2460 is clear on the minimum MTU for IPv6.
> 
> Anyone who pays money for such a thing should return it.

It is, actually, IPv6 for Low Power Area Networks and it does provide a “virtual MTU” of 1280 or better at layer 2 in order to facilitate moving IPv6 data over those networks. It does, however, provide additional optimizations to support the low power applications where these networks are common.

I recommend reading the RFC before saying that 6lowpan isn’t IPv6.

Owen