Re: [Int-area] IPv6 fragmentation for IPv4

"Templin, Fred L" <Fred.L.Templin@boeing.com> Tue, 23 May 2017 20:13 UTC

Return-Path: <Fred.L.Templin@boeing.com>
X-Original-To: int-area@ietfa.amsl.com
Delivered-To: int-area@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id DF40912943F for <int-area@ietfa.amsl.com>; Tue, 23 May 2017 13:13:33 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.221
X-Spam-Level:
X-Spam-Status: No, score=-4.221 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_PASS=-0.001] 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 PIQIwKmHh2_M for <int-area@ietfa.amsl.com>; Tue, 23 May 2017 13:13:30 -0700 (PDT)
Received: from phx-mbsout-02.mbs.boeing.net (phx-mbsout-02.mbs.boeing.net [130.76.184.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 2079012EB0E for <int-area@ietf.org>; Tue, 23 May 2017 13:13:16 -0700 (PDT)
Received: from localhost (localhost [127.0.0.1]) by phx-mbsout-02.mbs.boeing.net (8.14.4/8.14.4/DOWNSTREAM_MBSOUT) with SMTP id v4NKDFR1063100; Tue, 23 May 2017 13:13:15 -0700
Received: from XCH15-06-12.nw.nos.boeing.com (xch15-06-12.nw.nos.boeing.com [137.136.239.221]) by phx-mbsout-02.mbs.boeing.net (8.14.4/8.14.4/UPSTREAM_MBSOUT) with ESMTP id v4NKDESE063092 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=FAIL); Tue, 23 May 2017 13:13:14 -0700
Received: from XCH15-06-08.nw.nos.boeing.com (2002:8988:eede::8988:eede) by XCH15-06-12.nw.nos.boeing.com (2002:8988:efdd::8988:efdd) with Microsoft SMTP Server (TLS) id 15.0.1263.5; Tue, 23 May 2017 13:13:13 -0700
Received: from XCH15-06-08.nw.nos.boeing.com ([137.136.238.222]) by XCH15-06-08.nw.nos.boeing.com ([137.136.238.222]) with mapi id 15.00.1263.000; Tue, 23 May 2017 13:13:13 -0700
From: "Templin, Fred L" <Fred.L.Templin@boeing.com>
To: Joe Touch <touch@isi.edu>, "int-area@ietf.org" <int-area@ietf.org>
Thread-Topic: IPv6 fragmentation for IPv4
Thread-Index: AdLT3WVYMdiisvTeTLyu7THIVnRQuAAS8QEAAA0n34AAF4ZcAA==
Date: Tue, 23 May 2017 20:13:13 +0000
Message-ID: <1e04c4fdef5249ec816638aaf0584422@XCH15-06-08.nw.nos.boeing.com>
References: <da864471c7b648eea3d9d93029209660@XCH15-06-08.nw.nos.boeing.com> <e62dc1c0-c209-f834-c52c-9b8879048d86@isi.edu> <82ea9cb1ddec4c159fd4b4bdea90be41@XCH15-06-08.nw.nos.boeing.com>
In-Reply-To: <82ea9cb1ddec4c159fd4b4bdea90be41@XCH15-06-08.nw.nos.boeing.com>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
x-ms-exchange-transport-fromentityheader: Hosted
x-originating-ip: [137.136.248.6]
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-TM-AS-MML: disable
Archived-At: <https://mailarchive.ietf.org/arch/msg/int-area/j3XafAxeifGyoOW0rrggrlndt_M>
Subject: Re: [Int-area] IPv6 fragmentation for IPv4
X-BeenThere: int-area@ietf.org
X-Mailman-Version: 2.1.22
Precedence: list
List-Id: IETF Internet Area Mailing List <int-area.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/int-area>, <mailto:int-area-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/int-area/>
List-Post: <mailto:int-area@ietf.org>
List-Help: <mailto:int-area-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/int-area>, <mailto:int-area-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 23 May 2017 20:13:34 -0000

Joe,

> -----Original Message-----
> From: Int-area [mailto:int-area-bounces@ietf.org] On Behalf Of Templin, Fred L
> Sent: Tuesday, May 23, 2017 11:49 AM
> To: Joe Touch <touch@isi.edu>du>; int-area@ietf.org
> Subject: Re: [Int-area] IPv6 fragmentation for IPv4
> 
> Hi Joe,
> 
> > -----Original Message-----
> > From: Joe Touch [mailto:touch@isi.edu]
> > Sent: Tuesday, May 23, 2017 11:01 AM
> > To: Templin, Fred L <Fred.L.Templin@boeing.com>om>; int-area@ietf.org
> > Subject: Re: IPv6 fragmentation for IPv4
> >
> > Hi, Fred (et al.),
> >
> > On 5/23/2017 9:17 AM, Templin, Fred L wrote:
> > > Joe, I wanted to run an idea by you. We all know that IPv4 fragmentation has
> > > problems because of the 16-bit ID field. So, why not insert an IPv6 Fragment
> > > Header between the IPv4 header and the upper layer protocol data, then
> > > use IPv6-style fragmentation instead of IPv4 fragmentation?
> >
> > IPv4 fragmentation has several impediments:
> >     - small ID field
> >     - lack of a reassembly checksum
> >     - lack of a fixed-location flow ID
> >
> > Using IPv6-Frag as the next header solves only the first of these. The
> > last is significant - putting a new header would defeat IPv4 flow ECMP
> > even for the first fragment.
> 
> ECMP gateways could be updated to look at the ULP headers
> following the IPv6 Frag header in the first fragment.
> 
> > IPv6 includes a flow field that serves this
> > purpose.
> 
> How does it work for plain-old IPv4 fragmentation? I would think
> that ECMP gateways would look at the IP ID and try to associate
> the fragments so they all get equal ECMP treatment, i.e., the
> same as for vanilla IPv4.

Here's another think - since the IPv6 Frag Header already has a
32-bit IP ID that we are using for fragmentation, and since we
are asking the IPv4 header to set DF=1, the 16-bit IP ID field in
the IPv4 header is available for use as a flow field - right?

Thanks - Fred

> Thanks - Fred
> fred.l.templin@boeing.com
> 
> > Joe
> 
> _______________________________________________
> Int-area mailing list
> Int-area@ietf.org
> https://www.ietf.org/mailman/listinfo/int-area