Re: [v6ops] Stateful SLAAC (draft-ietf-v6ops-unique-ipv6-prefix-per-host)

David Farmer <farmer@umn.edu> Mon, 13 November 2017 15:34 UTC

Return-Path: <farmer@umn.edu>
X-Original-To: ipv6@ietfa.amsl.com
Delivered-To: ipv6@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id CF396129449 for <ipv6@ietfa.amsl.com>; Mon, 13 Nov 2017 07:34:01 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.299
X-Spam-Level:
X-Spam-Status: No, score=-4.299 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_MED=-2.3, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=umn.edu
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 miOAFcNLLkwi for <ipv6@ietfa.amsl.com>; Mon, 13 Nov 2017 07:34:00 -0800 (PST)
Received: from mta-p6.oit.umn.edu (mta-p6.oit.umn.edu [134.84.196.206]) (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 E9DCE129AC1 for <6man@ietf.org>; Mon, 13 Nov 2017 07:33:59 -0800 (PST)
Received: from localhost (unknown [127.0.0.1]) by mta-p6.oit.umn.edu (Postfix) with ESMTP id 4DBF15B0 for <6man@ietf.org>; Mon, 13 Nov 2017 15:33:59 +0000 (UTC)
X-Virus-Scanned: amavisd-new at umn.edu
Received: from mta-p6.oit.umn.edu ([127.0.0.1]) by localhost (mta-p6.oit.umn.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id vBHNSbRxION2 for <6man@ietf.org>; Mon, 13 Nov 2017 09:33:59 -0600 (CST)
Received: from mail-lf0-f69.google.com (mail-lf0-f69.google.com [209.85.215.69]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mta-p6.oit.umn.edu (Postfix) with ESMTPS id E896587A for <6man@ietf.org>; Mon, 13 Nov 2017 09:33:58 -0600 (CST)
Received: by mail-lf0-f69.google.com with SMTP id m74so2514373lfg.6 for <6man@ietf.org>; Mon, 13 Nov 2017 07:33:58 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=umn.edu; s=google; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=7xK1BAZybyMnDCg9U/mLC+lSPtVq0YNJCYZWHwhqQEk=; b=NhkQV5Ob0UZl6qUsNQwBnoAdncjlgUbwm2mcicn2cKI7A1nnelKn1TnlYuXQT93fdG zqQPA54bgXpyv5a7j6FNeJlKeENgt8WY9UxotGKVqahDE3EBTD/Tn9hFwX9qU1l2P9kE qSzfMaOjxN7Gc0pH63Cy88HHKN/G9jM6IsoAJupUG39BRpPOhtiNlYv1QMgWHCWtA+Pl 7mxQywiMr6FhgciK0m+hkOsNtj88hsz0YNKnSNrXfPtrp2jCFx4SSbey3SJOljmIk154 DG3HYmpKIQDSv/cLpOIt191p5xauf7O+aN++7IiWIktsJKZ8KORrPHxwAn/DsEYGdES9 O2YA==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=7xK1BAZybyMnDCg9U/mLC+lSPtVq0YNJCYZWHwhqQEk=; b=tg0UVrH0uihW3YpazuiSDITZJrMubUy+v25eE/DdXbuU7ACouagRUDyPWPqmq+fERI 6G1HllwCVWamIi+i4aGT8BilbzV2C1MZQzkd05JbqZ02tFXTqqNaXuXcg3HACN2gvHyH ZV5eAQcn4O99KSUsQgbe6eEcxarbKYl12qqa29wTXkuo13otrk4XuIkeqTmtasLWrCLx DjGBihPe7tEa2Sap/QQK5suXr/dD+Roy1pkIyKvC9L+16HGjUiz18boUD7nlqdhccbnO bPWbTUnUDJi1i90ZbZHAkUjm/X6wHxG34RGIgybKw5IK+AURQe8uN+VjvNlWJY17ZM6F 8yYg==
X-Gm-Message-State: AJaThX76djuHI5Ouwf4D6ohcgRftBZd3P7VoF2BTol//V2doptXoH2lS WF7DuERWl9dX57WBYDGm0siCS14sjy1nEe9UVlfyFTRVJe7cqPtQYXo79rXQ6QjPjGf+uYf0GtP N17OFHuFIMkCLbhZ40OyzSW7G
X-Received: by 10.46.20.79 with SMTP id 15mr3296374lju.125.1510587237098; Mon, 13 Nov 2017 07:33:57 -0800 (PST)
X-Google-Smtp-Source: AGs4zMbO1Ac9GRP+7ZemyoFa9klH7KsShMOJDRfGKeVsPlzOVTexNO87c3txvfvIWR4xOVi9M0FK+td578WQtPUdU50=
X-Received: by 10.46.20.79 with SMTP id 15mr3296364lju.125.1510587236854; Mon, 13 Nov 2017 07:33:56 -0800 (PST)
MIME-Version: 1.0
Received: by 10.25.217.89 with HTTP; Mon, 13 Nov 2017 07:33:56 -0800 (PST)
In-Reply-To: <d8c7dd2e-821c-b2ec-583f-92c42af55ae3@si6networks.com>
References: <be9724f5-2ff5-d90c-2749-ecae2c628b78@si6networks.com> <e40697ca-8017-c9d2-c25d-89087046c9cf@gmail.com> <207f040a-7fe2-9434-e7a5-f546b26fdf63@strayalpha.com> <CAKD1Yr26NK2osApYZBm8Yd=0X7xcetrxojp6=JHOEAu9BB0q8A@mail.gmail.com> <8ca59610-2d25-2be4-9d2c-9b1a75fd3ace@si6networks.com> <E67105A3-396B-403C-B741-E9E01CFB5CE7@employees.org> <e7ec4633-8d45-1cff-ce37-48dafd488e13@si6networks.com> <BBAB48C0-384B-4380-9359-7965C7C61D58@employees.org> <4b7e8e53-ea7a-f84d-92cf-a9a113c200ce@si6networks.com> <CAKD1Yr1NG93Jv7E6hKY4BKApwJg6uG0wAgUL74cw1Fb5VsKnUg@mail.gmail.com> <14d489ec-0b28-8fe5-e28c-35a1f4fc15de@si6networks.com> <CAJc3aaPb8vOxfUVk-6sQNGpftegPCgb+j3OyGD55rmCado+VZw@mail.gmail.com> <a4a380b0-d69c-1c2c-fedc-0a3da2a8060a@si6networks.com> <CAJc3aaPg=qOpiwJ29Bq92m2RfZ-VDJtLWb-GgZV7bXP6iELiRA@mail.gmail.com> <d86e4678-7634-5574-3151-056fe92602aa@si6networks.com> <CAPt1N1=qM7kk_NQcm=ibnhv6gf_+JGkUyww6KCMOQ4Lsr8Ttdg@mail.gmail.com> <d8c7dd2e-821c-b2ec-583f-92c42af55ae3@si6networks.com>
From: David Farmer <farmer@umn.edu>
Date: Mon, 13 Nov 2017 09:33:56 -0600
Message-ID: <CAN-Dau1yMCMAJGhjgEG41L14uPX_=WwcHfcWpPUfjJse6ZK3rg@mail.gmail.com>
Subject: Re: [v6ops] Stateful SLAAC (draft-ietf-v6ops-unique-ipv6-prefix-per-host)
To: Fernando Gont <fgont@si6networks.com>
Cc: Ted Lemon <mellon@fugue.com>, IPv6 Ops WG <v6ops@ietf.org>, "6man@ietf.org" <6man@ietf.org>
Content-Type: multipart/alternative; boundary="f403045fbe34a7c4ae055ddefff9"
Archived-At: <https://mailarchive.ietf.org/arch/msg/ipv6/_JqgCHPj85pzoCdWZ_oyd45MoJk>
X-BeenThere: ipv6@ietf.org
X-Mailman-Version: 2.1.22
Precedence: list
List-Id: "IPv6 Maintenance Working Group \(6man\)" <ipv6.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/ipv6>, <mailto:ipv6-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/ipv6/>
List-Post: <mailto:ipv6@ietf.org>
List-Help: <mailto:ipv6-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/ipv6>, <mailto:ipv6-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 13 Nov 2017 15:34:02 -0000

On Mon, Nov 13, 2017 at 8:57 AM, Fernando Gont <fgont@si6networks.com>
wrote:

> Ted,
>
> On 11/13/2017 10:31 PM, Ted Lemon wrote:
> > Fernando, the document is in AUTH48. If there is a technical problem
> > with it that is sufficient to pull it out of the publication queue at
> > this point, I haven't heard it yet. I think it would be nice to add a
> > little advice on how to manage the state, but it's up to the authors to
> > do this or not. This discussion is getting a bit old.
>
> The technical problem is that this is a v6ops document making SLAAC
> stateful. As discussed, making SLAAC stateful brings breakage scenarios
> not present in SLAAC, and that is certainly not a minor change.
>
> And having folks noted that they have implemented this sort of behavior
> without changing SLAAC, the low-level protocol details in Section 4 are
> even less unwarranted.
>
> It is not my call what's the proper action. But I do note that this is
> yet another BCP that rather that essentially disregards work of other wg
> (dhc), unnecessarily. Are you are pushing a BCP with a mechanism that is
> so underspecified, that folks meaning to implement this are likely to
> introduce breakage.
>
> That said, it is not my call what's the proper action to follow. My
> intent (noted to e.g. Suresh off-line) is not to obstruct the document,
> but to avoid breakage -- particularly when it's unwarranted.
>

You claim this is making SLAAC stateful by adding state to the router.
However, if anything this reduces the state the router needs to track.
Currently the router has to track address state of  O(NxM).  Where N =
Number Hosts, and M = Average Number Addresses used per Host.  With Unique
Prefix per host, the router only has to track prefix state of O(N).
Allowing a host to use as many addresses as it sees fit without impacting
the amount of state the router has to track.

Further, it seems to me that if anything it's Neighbor Discovery that is
changed, and not SLAAC, and Neighbor Discovery has always been stateful.
Now I don't believe the Neighbor Discovery protocol is actually being
changed, it is merely being implemented differently within the variations
allowed by the protocol.

Finally, this discussion has relieved that there this draft is incomplete
in several ways.  However this document is not any more incomplete than
many other documents already approved by the IESG and implemented on
thousands or even millions of hosts.  That is why we revise documents, we
never get it right the first time.

Thanks.

-- 
===============================================
David Farmer               Email:farmer@umn.edu
Networking & Telecommunication Services
Office of Information Technology
University of Minnesota
2218 University Ave SE        Phone: 612-626-0815
Minneapolis, MN 55414-3029   Cell: 612-812-9952
===============================================