Re: [Softwires] [nvo3] Is it feasible to perform fragmentation on UDP encapsulated packets.

Joe Touch <touch@isi.edu> Thu, 02 June 2016 18:09 UTC

Return-Path: <touch@isi.edu>
X-Original-To: softwires@ietfa.amsl.com
Delivered-To: softwires@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id AF6A312B04C; Thu, 2 Jun 2016 11:09:07 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -8.326
X-Spam-Level:
X-Spam-Status: No, score=-8.326 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, RP_MATCHES_RCVD=-1.426] autolearn=ham autolearn_force=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 068xYN7sL5jT; Thu, 2 Jun 2016 11:09:06 -0700 (PDT)
Received: from boreas.isi.edu (boreas.isi.edu [128.9.160.161]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 111AC12B022; Thu, 2 Jun 2016 11:09:06 -0700 (PDT)
Received: from [128.9.184.178] ([128.9.184.178]) (authenticated bits=0) by boreas.isi.edu (8.13.8/8.13.8) with ESMTP id u52I8JFa001915 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NOT); Thu, 2 Jun 2016 11:08:21 -0700 (PDT)
To: otroan@employees.org, Xuxiaohu <xuxiaohu@huawei.com>
References: <E83B905A-FF6D-4996-B71A-7921DE4B133B@ericsson.com> <BFC09F5C-D6DF-4B6B-AA95-03919B9F09FB@cisco.com> <573E2A0E.1060609@isi.edu> <1FEE3F8F5CCDE64C9A8E8F4AD27C19EE0D54EB60@NKGEML515-MBX.china.huawei.com> <573F453C.5060908@isi.edu> <1FEE3F8F5CCDE64C9A8E8F4AD27C19EE0D554B73@NKGEML515-MBS.china.huawei.com> <5743303C.5040109@isi.edu> <1FEE3F8F5CCDE64C9A8E8F4AD27C19EE0D55514C@NKGEML515-MBS.china.huawei.com> <5743DD16.3050506@isi.edu> <1FEE3F8F5CCDE64C9A8E8F4AD27C19EE0D555482@NKGEML515-MBS.china.huawei.com> <57448C14.2060203@isi.edu> <1FEE3F8F5CCDE64C9A8E8F4AD27C19EE0D5557DE@NKGEML515-MBS.china.huawei.com> <9c462520-eb8e-fcd0-0a08-228f80fbc779@isi.edu> <1FEE3F8F5CCDE64C9A8E8F4AD27C19EE0D5596E0@NKGEML515-MBS.china.huawei.com> <8790AF6F-CCD6-43AC-A50E-957B037643F1@employees.org>
From: Joe Touch <touch@isi.edu>
Message-ID: <57507611.5010801@isi.edu>
Date: Thu, 2 Jun 2016 11:08:17 -0700
User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.7.2
MIME-Version: 1.0
In-Reply-To: <8790AF6F-CCD6-43AC-A50E-957B037643F1@employees.org>
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 7bit
X-ISI-4-43-8-MailScanner: Found to be clean
X-MailScanner-From: touch@isi.edu
Archived-At: <http://mailarchive.ietf.org/arch/msg/softwires/KsEYrCr5J7l1eXFRgO6HI7Eu7D0>
Cc: Softwires WG <softwires@ietf.org>, "nvo3@ietf.org" <nvo3@ietf.org>, "int-area@ietf.org" <int-area@ietf.org>, "lisp@ietf.org" <lisp@ietf.org>, "tsvwg@ietf.org" <tsvwg@ietf.org>
Subject: Re: [Softwires] [nvo3] Is it feasible to perform fragmentation on UDP encapsulated packets.
X-BeenThere: softwires@ietf.org
X-Mailman-Version: 2.1.17
Precedence: list
List-Id: softwires wg discussion list <softwires.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/softwires>, <mailto:softwires-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/softwires/>
List-Post: <mailto:softwires@ietf.org>
List-Help: <mailto:softwires-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/softwires>, <mailto:softwires-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 02 Jun 2016 18:09:08 -0000


On 5/27/2016 3:50 AM, otroan@employees.org wrote:
> It is not possible to implement reassembly complying with IETF RFCs.

a) ATM does this at ridiculously high fragment rates. Granted IP frags
can come out of order, but the fragments are generally much larger.

b) What is the alternative, given we have minimum MTU requirements?

If you're limiting yourself to IPv4 payloads where DF=0, sure, there
there is an alternative. But you've just disabled IPv6 and IPv4 with DF=1.

I.e., it's not possible to NOT implement this and comply with IETF RFCs.

Joe