From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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 lists.bufferbloat.net (Postfix) with ESMTPS id 4FB5D3B29E; Tue, 18 Sep 2018 20:43:25 -0400 (EDT) Received: from potemkin.univ-paris7.fr (potemkin.univ-paris7.fr [IPv6:2001:660:3301:8000::1:1]) by korolev.univ-paris7.fr (8.14.4/8.14.4/relay1/75695) with ESMTP id w8J0hLqH031698 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Wed, 19 Sep 2018 02:43:21 +0200 Received: from mailhub.math.univ-paris-diderot.fr (mailhub.math.univ-paris-diderot.fr [81.194.30.253]) by potemkin.univ-paris7.fr (8.14.4/8.14.4/relay2/75695) with ESMTP id w8J0hL73005584; Wed, 19 Sep 2018 02:43:21 +0200 Received: from mailhub.math.univ-paris-diderot.fr (localhost [127.0.0.1]) by mailhub.math.univ-paris-diderot.fr (Postfix) with ESMTP id D6B9AEB22E; Wed, 19 Sep 2018 02:43:21 +0200 (CEST) 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 t44uE4Pt_ju1; Wed, 19 Sep 2018 02:43:20 +0200 (CEST) Received: from trurl.irif.fr (unknown [78.194.40.74]) (Authenticated sender: jch) by mailhub.math.univ-paris-diderot.fr (Postfix) with ESMTPSA id C2137EB200; Wed, 19 Sep 2018 02:43:20 +0200 (CEST) Date: Wed, 19 Sep 2018 02:43:20 +0200 Message-ID: <87zhweb9lj.wl-jch@irif.fr> From: Juliusz Chroboczek To: Dave Taht Cc: babel-users@lists.alioth.debian.org, Make-Wifi-fast , ecn-sane@lists.bufferbloat.net In-Reply-To: References: <87efdqcs28.wl-jch@irif.fr> <8736u6cpyu.wl-jch@irif.fr> 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 [IPv6:2001:660:3301:8000::1:2]); Wed, 19 Sep 2018 02:43:21 +0200 (CEST) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.7 (potemkin.univ-paris7.fr [194.254.61.141]); Wed, 19 Sep 2018 02:43:21 +0200 (CEST) X-Miltered: at korolev with ID 5BA19BA9.000 by Joe's j-chkmail (http : // j-chkmail dot ensmp dot fr)! X-Miltered: at potemkin with ID 5BA19BA9.001 by Joe's j-chkmail (http : // j-chkmail dot ensmp dot fr)! X-j-chkmail-Enveloppe: 5BA19BA9.000 from potemkin.univ-paris7.fr/potemkin.univ-paris7.fr/null/potemkin.univ-paris7.fr/ X-j-chkmail-Enveloppe: 5BA19BA9.001 from mailhub.math.univ-paris-diderot.fr/mailhub.math.univ-paris-diderot.fr/null/mailhub.math.univ-paris-diderot.fr/ X-j-chkmail-Score: MSGID : 5BA19BA9.000 on korolev.univ-paris7.fr : j-chkmail score : . : R=. U=. O=. B=0.000 -> S=0.000 X-j-chkmail-Score: MSGID : 5BA19BA9.001 on potemkin.univ-paris7.fr : j-chkmail score : . : R=. U=. O=. B=0.000 -> S=0.000 X-j-chkmail-Status: Ham X-j-chkmail-Status: Ham Subject: Re: [Make-wifi-fast] [Babel-users] reducing delays in wifi mcast queues X-BeenThere: make-wifi-fast@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 19 Sep 2018 00:43:25 -0000 >> Interesting. AFAIK, ECN is only considered by AQM queues, so this implies >> there's a queue in the way that's dropping Babel packets. > There's fq_codel on every queue, which does FQ, and codel assumes > everything is at least moderately TCP friendly (and/or reasonably > responsive to ecn marks) Jonathan seems to agree with you. Were your tests run with more than 60 installed routes or so? >> Or perhaps, if we know which queue that is, >> we could modify Babel's packet scheduling to be more AQM friendly? > How would you describe babel's packet schedulig now? The main flaw is that it sends periodic updates as a burst of back-to-back full-size packets. That could trigger Codel if you had more than 60 routes or so. > So dumping packets in there at a rate no more than 20ms each (short term > burst of 100ms) - relative to whatever bandwidth can be achieved vs the > other flows. Right. Guilty as charged. -- Juliusz