IETF Logo Mail Archive

Re: [Tsv-art] ECMP [Tsvart last call review of draft-ietf-opsec-ipv6-eh-filtering-06]

Nick Hilliard <nick@foobar.org> Thu, 06 December 2018 22:02 UTC

Return-Path: <nick@foobar.org>
X-Original-To: tsv-art@ietfa.amsl.com
Delivered-To: tsv-art@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id C3A69130EEC; Thu, 6 Dec 2018 14:02:51 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.2
X-Spam-Level:
X-Spam-Status: No, score=-4.2 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, SPF_PASS=-0.001, URIBL_BLOCKED=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 nYl80elipMCB; Thu, 6 Dec 2018 14:02:49 -0800 (PST)
Received: from mail.netability.ie (mail.netability.ie [IPv6:2a03:8900:0:100::5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id D2E44130E93; Thu, 6 Dec 2018 14:02:48 -0800 (PST)
X-Envelope-To: tsv-art@ietf.org
Received: from crumpet.local (089-101-070074.ntlworld.ie [89.101.70.74] (may be forged)) (authenticated bits=0) by mail.netability.ie (8.15.2/8.15.2) with ESMTPSA id wB6M2je7089038 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 6 Dec 2018 22:02:45 GMT (envelope-from nick@foobar.org)
X-Authentication-Warning: cheesecake.ibn.ie: Host 089-101-070074.ntlworld.ie [89.101.70.74] (may be forged) claimed to be crumpet.local
To: Brian E Carpenter <brian.e.carpenter@gmail.com>
Cc: tsv-art <tsv-art@ietf.org>, OPSEC <opsec@ietf.org>, IETF-Discussion Discussion <ietf@ietf.org>, draft-ietf-opsec-ipv6-eh-filtering.all@ietf.org
References: <CAL9jLaYHVdHr+rVoWeNtXTXgLxbTaX8V9gn3424tvsLW60Kvow@mail.gmail.com> <5E70C208-0B31-4333-BB8C-4D45E678E878@isc.org> <CAN-Dau0go6_Puf0A9e7KBpk0ApJBUvcxYtezxnwNc-8pKJ3PwQ@mail.gmail.com> <4D69FA8E-FB8A-4A16-9CA6-690D8AE33C9E@strayalpha.com> <20181205122142.GJ1543@Space.Net> <F17C4944-09EC-4AAC-84A0-B660E36AAE89@strayalpha.com> <20181205133821.GL1543@Space.Net> <B6280E0C-6B20-43C1-BB34-170FB06F1EF7@strayalpha.com> <20181205135723.GN1543@Space.Net> <54C715AE-8931-4FA9-AA01-2311EB0055F0@employees.org> <20181205164558.GQ1543@Space.Net> <CCFEFC5B-53AE-4079-B64A-A72A71274FAD@employees.org> <cda0e10e-a56d-4598-dcd4-eabeeac52fb0@gmail.com> <a1b478a7-4396-3d9e-0282-c8c66250526c@gmail.com> <f86a07c8-c421-56db-005c-4db3ce4f3fe0@gmail.com> <3744b28c-3a5a-1ce4-9ff7-5374804d332e@gmail.com>
From: Nick Hilliard <nick@foobar.org>
Message-ID: <35277330-4743-4690-8ae0-9a9ab7e34f05@foobar.org>
Date: Thu, 06 Dec 2018 22:02:43 +0000
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:52.0) Gecko/20100101 PostboxApp/6.1.6
MIME-Version: 1.0
In-Reply-To: <3744b28c-3a5a-1ce4-9ff7-5374804d332e@gmail.com>
Content-Type: text/plain; charset="utf-8"; format="flowed"
Content-Language: en-GB
Content-Transfer-Encoding: 7bit
Archived-At: <https://mailarchive.ietf.org/arch/msg/tsv-art/CNv4ySy1sA7o9vsaqM5hD0gQr5E>
Subject: Re: [Tsv-art] ECMP [Tsvart last call review of draft-ietf-opsec-ipv6-eh-filtering-06]
X-BeenThere: tsv-art@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Transport Area Review Team <tsv-art.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/tsv-art>, <mailto:tsv-art-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/tsv-art/>
List-Post: <mailto:tsv-art@ietf.org>
List-Help: <mailto:tsv-art-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/tsv-art>, <mailto:tsv-art-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 06 Dec 2018 22:02:52 -0000

Brian E Carpenter wrote on 06/12/2018 20:35:
> But there's a preliminary question: how widely is the flow label set
> by sending hosts? The answer is: widely, by modern o/s releases. But not
> much, by legacy o/s releases.

more to the point, if you were going to implement a forwarding device, 
do you depend solely on the flow label?

This gives end-user device control over the hashing path on a purely 
discretionary basis.  I.e. and end user can change the flow label and 
consequently make their own decisions about which network path to use, 
without affecting any other transmission characteristic of the network 
flow, e.g. port numbers, IP addresses, etc.

Operationally, flow labels can cause grief.  APNIC had a blog posting on 
this a while back

https://blog.apnic.net/2018/01/11/ipv6-flow-label-misuse-hashing/

Most devices allow the operator to selectively use flow labels as an 
entropy source for hashing.

Nick

v2.23.0 | Report a Bug | By Email