Re: [homenet] Alia Atlas' No Objection on draft-ietf-homenet-hncp-09: (with COMMENT)

Juliusz Chroboczek <jch@pps.univ-paris-diderot.fr> Mon, 23 November 2015 19:02 UTC

Return-Path: <jch@pps.univ-paris-diderot.fr>
X-Original-To: homenet@ietfa.amsl.com
Delivered-To: homenet@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 810861ACDE9; Mon, 23 Nov 2015 11:02:15 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: 0.349
X-Spam-Level:
X-Spam-Status: No, score=0.349 tagged_above=-999 required=5 tests=[BAYES_40=-0.001, HELO_EQ_FR=0.35] autolearn=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 eelkuMPGc36T; Mon, 23 Nov 2015 11:02:14 -0800 (PST)
Received: from korolev.univ-paris7.fr (korolev.univ-paris7.fr [IPv6:2001:660:3301:8000::1:2]) (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 A67381ACDD5; Mon, 23 Nov 2015 11:02:13 -0800 (PST)
Received: from mailhub.math.univ-paris-diderot.fr (mailhub.math.univ-paris-diderot.fr [81.194.30.253]) by korolev.univ-paris7.fr (8.14.4/8.14.4/relay1/56228) with ESMTP id tANJ2Amb027523; Mon, 23 Nov 2015 20:02:10 +0100
Received: from mailhub.math.univ-paris-diderot.fr (localhost [127.0.0.1]) by mailhub.math.univ-paris-diderot.fr (Postfix) with ESMTP id 7C93761FA3; Mon, 23 Nov 2015 20:02:10 +0100 (CET)
X-Virus-Scanned: amavisd-new at math.univ-paris-diderot.fr
Received: from mailhub.math.univ-paris-diderot.fr ([127.0.0.1]) by mailhub.math.univ-paris-diderot.fr (mailhub.math.univ-paris-diderot.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id JxG5Jp1ZKpDI; Mon, 23 Nov 2015 20:02:08 +0100 (CET)
Received: from trurl.pps.univ-paris-diderot.fr (col75-1-78-194-40-74.fbxo.proxad.net [78.194.40.74]) (Authenticated sender: jch) by mailhub.math.univ-paris-diderot.fr (Postfix) with ESMTPSA id C004B61FA2; Mon, 23 Nov 2015 20:02:06 +0100 (CET)
Date: Mon, 23 Nov 2015 20:02:11 +0100
Message-ID: <87lh9oo7yk.wl-jch@pps.univ-paris-diderot.fr>
From: Juliusz Chroboczek <jch@pps.univ-paris-diderot.fr>
To: Markus Stenberg <markus.stenberg@iki.fi>
In-Reply-To: <A618CB70-9957-48AB-B49D-2C1C65F12D0D@iki.fi>
References: <20151120170938.3181.9355.idtracker@ietfa.amsl.com> <A618CB70-9957-48AB-B49D-2C1C65F12D0D@iki.fi>
User-Agent: Wanderlust/2.15.9
MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue")
Content-Type: text/plain; charset=US-ASCII
X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.7 (korolev.univ-paris7.fr [194.254.61.138]); Mon, 23 Nov 2015 20:02:11 +0100 (CET)
X-Miltered: at korolev with ID 565362B2.000 by Joe's j-chkmail (http : // j-chkmail dot ensmp dot fr)!
X-j-chkmail-Enveloppe: 565362B2.000 from mailhub.math.univ-paris-diderot.fr/mailhub.math.univ-paris-diderot.fr/null/mailhub.math.univ-paris-diderot.fr/<jch@pps.univ-paris-diderot.fr>
X-j-chkmail-Score: MSGID : 565362B2.000 on korolev.univ-paris7.fr : j-chkmail score : . : R=. U=. O=. B=0.000 -> S=0.000
X-j-chkmail-Status: Ham
Archived-At: <http://mailarchive.ietf.org/arch/msg/homenet/n1pIJuNNN9F5ZWQGqQ9QmmUfB3w>
Cc: draft-ietf-homenet-hncp@ietf.org, homenet@ietf.org, The IESG <iesg@ietf.org>, Alia Atlas <akatlas@gmail.com>
Subject: Re: [homenet] Alia Atlas' No Objection on draft-ietf-homenet-hncp-09: (with COMMENT)
X-BeenThere: homenet@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: IETF Homenet WG mailing list <homenet.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/homenet>, <mailto:homenet-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/homenet/>
List-Post: <mailto:homenet@ietf.org>
List-Help: <mailto:homenet-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/homenet>, <mailto:homenet-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 23 Nov 2015 19:02:15 -0000

>> While src-dest routing is certainly a solution - and an interesting
>> one - it doesn't seem at all appropriate for an HNCP spec to assert
>> that it is necessary.

> True. However, we were asked to describe the applicability, and
> I consider e.g. tunneling solution inferior so I would rather not
> propose that here.

I was under the impression that there was consensus that tunnelling is
a bad idea, and that source-specific routing is superior.  I may be
mis-reading Alia, but perhaps she means that some deployments might not
require the added complexity of source-specific routing, and might be able
to get away with ordinary next-hop routing.  (Alia, apologies if
I misunderstood.)

Recall that our main concern is to ensure that Homenet routers from
different vendors interoperate.  Source-specific routing, when done right,
interoperates with ordinary next-hop routing under the following
conditions: (1) all edge routers are source-specific, (2) there is
a connected backbone of source-specific routers, and (3) at least one of
the routers in the backbone announces a non-specific default route.  (1)
and (3) are easy enough, but (2) is problematic: it is a global condition,
one that can only be verified with global knowledge of the topology.

So I agree with Markus -- while it might be possible to get away with
a weaker requirement, it is way simpler to make source-specific routing
a MUST.  If there is market demand, we might want to write a different
document that describes a weaker set of requirements for interior-only
(non-gateway-capable) Homenet nodes.

(A more desirable alternative, of course, would be to split the
requirements in HNCP into HNCP requirements and Homenet requirements, but
I gather that there's consensus that it's somewhat late to embark on such
an ambitious project.  I rather agree with that assessment -- we need to
get Homenet out of the door quickly, lest people start deploying IPv6 NAT.)

-- Juliusz