Re: [homenet] homenet-babel-profile: determining link type

Juliusz Chroboczek <jch@irif.fr> Tue, 21 November 2017 12:29 UTC

Return-Path: <jch@irif.fr>
X-Original-To: homenet@ietfa.amsl.com
Delivered-To: homenet@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id F146312947B for <homenet@ietfa.amsl.com>; Tue, 21 Nov 2017 04:29:38 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.901
X-Spam-Level:
X-Spam-Status: No, score=-1.901 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_NONE=-0.0001, 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 Qi8cSmYOGUi8 for <homenet@ietfa.amsl.com>; Tue, 21 Nov 2017 04:29:37 -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 1177612946E for <homenet@ietf.org>; Tue, 21 Nov 2017 04:29:36 -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/relay1/75695) with ESMTP id vALCTWbK029173; Tue, 21 Nov 2017 13:29:32 +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 89757EB217; Tue, 21 Nov 2017 13:29:32 +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 BiCCzI_uTZXh; Tue, 21 Nov 2017 13:29:31 +0100 (CET)
Received: from lanthane.pps.univ-paris-diderot.fr (unknown [172.23.36.54]) (Authenticated sender: jch) by mailhub.math.univ-paris-diderot.fr (Postfix) with ESMTPSA id 60EACEB216; Tue, 21 Nov 2017 13:29:31 +0100 (CET)
Received: from localhost ([::1] helo=lanthane.irif.fr) by lanthane.pps.univ-paris-diderot.fr with esmtp (Exim 4.89) (envelope-from <jch@irif.fr>) id 1eH7gA-00085S-VT; Tue, 21 Nov 2017 13:29:31 +0100
Date: Tue, 21 Nov 2017 13:29:30 +0100
Message-ID: <7i7euj4xxx.wl-jch@irif.fr>
From: Juliusz Chroboczek <jch@irif.fr>
To: Michael Richardson <mcr+ietf@sandelman.ca>
Cc: "STARK, BARBARA H" <bs7652@att.com>, "homenet@ietf.org" <homenet@ietf.org>
In-Reply-To: <22889.1511226157@obiwan.sandelman.ca>
References: <2D09D61DDFA73D4C884805CC7865E6114DCBBF72@GAALPA1MSGUSRBF.ITServices.sbc.com> <22889.1511226157@obiwan.sandelman.ca>
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]); Tue, 21 Nov 2017 13:29:32 +0100 (CET)
X-Miltered: at korolev with ID 5A141C2C.003 by Joe's j-chkmail (http : // j-chkmail dot ensmp dot fr)!
X-j-chkmail-Enveloppe: 5A141C2C.003 from mailhub.math.univ-paris-diderot.fr/mailhub.math.univ-paris-diderot.fr/null/mailhub.math.univ-paris-diderot.fr/<jch@irif.fr>
X-j-chkmail-Score: MSGID : 5A141C2C.003 on korolev.univ-paris7.fr : j-chkmail score : . : R=. U=. O=. B=0.000 -> S=0.000
X-j-chkmail-Status: Ham
Archived-At: <https://mailarchive.ietf.org/arch/msg/homenet/Z0wwEqq_Pk96v4H1j0kdl2zz4k8>
Subject: Re: [homenet] homenet-babel-profile: determining link type
X-BeenThere: homenet@ietf.org
X-Mailman-Version: 2.1.22
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: Tue, 21 Nov 2017 12:29:39 -0000

>> Should we really only suggest that the router dynamically probe the
>> quality of wireless links? Or would it make sense to suggest dynamic
>> probing of all links, because assuming the entire path between 2
>> routers uses a single physical layer technology may not be a good
>> assumption?

> I agree that is should probe all interfaces!

Then you need to define suitable algorithms for non-WiFi interfaces.

I'm open to collaboration, of course, since dynamically computed metrics
is something that's close to my heart.  (Somebody promised to send me some
G.hn hardware at some point, but they must have forgotten.)

> Some wires might be better than others; assume use of random joiners between
> cat3,cat5,cat6 and chicken wire in the home.

Babeld's wireless link quality estimation triggers around 5% packet loss;
on WiFi, it only works because we're careful to send frames that are not
protected by ARQ -- after ARQ, the loss rate is way below that, even on
dodgy links.

You're not going to get loss rates that over chicken wire (unless you've
got really bad quality chicken wire).

> (a booth at N+I back in ~2000 or something had a very nice GbE over
> barbed wire demo)

Somewhat charged politically ;-)

-- Juliusz