Re: [Int-area] IPv6 fragmentation for IPv4

"Templin, Fred L" <Fred.L.Templin@boeing.com> Tue, 23 May 2017 20:45 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 B95F312EB22 for <int-area@ietfa.amsl.com>; Tue, 23 May 2017 13:45:52 -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 eJ9NS0lT5gXL for <int-area@ietfa.amsl.com>; Tue, 23 May 2017 13:45:51 -0700 (PDT)
Received: from phx-mbsout-01.mbs.boeing.net (phx-mbsout-01.mbs.boeing.net [130.76.184.178]) (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 817FF12EB21 for <int-area@ietf.org>; Tue, 23 May 2017 13:45:51 -0700 (PDT)
Received: from localhost (localhost [127.0.0.1]) by phx-mbsout-01.mbs.boeing.net (8.14.4/8.14.4/DOWNSTREAM_MBSOUT) with SMTP id v4NKjpCv023315; Tue, 23 May 2017 13:45:51 -0700
Received: from XCH15-06-07.nw.nos.boeing.com (xch15-06-07.nw.nos.boeing.com [137.136.238.213]) by phx-mbsout-01.mbs.boeing.net (8.14.4/8.14.4/UPSTREAM_MBSOUT) with ESMTP id v4NKjgEd023277 (version=TLSv1/SSLv3 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=FAIL); Tue, 23 May 2017 13:45:42 -0700
Received: from XCH15-06-08.nw.nos.boeing.com (2002:8988:eede::8988:eede) by XCH15-06-07.nw.nos.boeing.com (2002:8988:eed5::8988:eed5) with Microsoft SMTP Server (TLS) id 15.0.1263.5; Tue, 23 May 2017 13:45:42 -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 13:45:41 -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: AdLT3WVYMdiisvTeTLyu7THIVnRQuAAS8QEAAA0n34AAF4ZcAP//AfaAgABvzFA=
Date: Tue, 23 May 2017 20:45:41 +0000
Message-ID: <d17df7228aae4360a7b517ebd8dfae42@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> <1e04c4fdef5249ec816638aaf0584422@XCH15-06-08.nw.nos.boeing.com> <7b58e6e2-8f58-0f80-494c-11053257759c@isi.edu>
In-Reply-To: <7b58e6e2-8f58-0f80-494c-11053257759c@isi.edu>
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="utf-8"
Content-Transfer-Encoding: base64
MIME-Version: 1.0
X-TM-AS-MML: disable
Archived-At: <https://mailarchive.ietf.org/arch/msg/int-area/V2xB3xoZiyv2ew_oglvIIPxuxR8>
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 20:45:53 -0000

Hi Joe,

> -----Original Message-----
> From: Joe Touch [mailto:touch@isi.edu]
> Sent: Tuesday, May 23, 2017 1:22 PM
> To: Templin, Fred L <Fred.L.Templin@boeing.com>om>; int-area@ietf.org
> Subject: Re: IPv6 fragmentation for IPv4
> 
> 
> 
> On 5/23/2017 1:13 PM, Templin, Fred L wrote:
> > 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?
> Except for all those devices that look only at the IPv4 header. In that
> case, redefining the IPv4 header this way could interfere with
> mechanisms to manage NAT traversal based based on ID context.

What was it that your document said about the setting of IP ID when
DF=1? Shouldn't it be OK to set the ID to some value of our own
choosing, e.g., a hash of the 5-tuple of the original packet?

> Finally, how do you know when you can even use this? Legacy devices
> could choke on such packets - whether routers or endpoints.

That is a real concern, yes. For the same reason that new transports
like SCTP and DCCP have been proven difficult to deploy. With this
proposal, ip-proto-44 would be just another protocol that middleboxes
block. But, maybe it would work in private internetworks such as
an enterprise network.

Thanks - Fred

> Joe