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 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by huchra.bufferbloat.net (Postfix) with ESMTPS id AAA0521F224 for ; Sun, 21 Jun 2015 08:32:13 -0700 (PDT) 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/relay1/56100) with ESMTP id t5LFW9r6025194 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Sun, 21 Jun 2015 17:32:09 +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/relay2/56228) with ESMTP id t5LFW9mq014902; Sun, 21 Jun 2015 17:32:09 +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 9E48161F9A; Sun, 21 Jun 2015 17:32:09 +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 nnXhGG8bcltb; Sun, 21 Jun 2015 17:32:08 +0200 (CEST) Received: from pirx.pps.univ-paris-diderot.fr (unknown [78.194.40.74]) (Authenticated sender: jch) by mailhub.math.univ-paris-diderot.fr (Postfix) with ESMTPSA id 16AA461F9D; Sun, 21 Jun 2015 17:32:08 +0200 (CEST) Date: Sun, 21 Jun 2015 17:32:07 +0200 Message-ID: <87wpyx3wnc.wl-jch@pps.univ-paris-diderot.fr> From: Juliusz Chroboczek To: Dave Taht In-Reply-To: References: User-Agent: Wanderlust/2.15.9 MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; format=flowed; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.7 (korolev.univ-paris7.fr [IPv6:2001:660:3301:8000::1:2]); Sun, 21 Jun 2015 17:32:09 +0200 (CEST) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.7 (potemkin.univ-paris7.fr [194.254.61.141]); Sun, 21 Jun 2015 17:32:09 +0200 (CEST) X-Miltered: at korolev with ID 5586D8F9.000 by Joe's j-chkmail (http : // j-chkmail dot ensmp dot fr)! 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B=0.000 -> S=0.000 X-j-chkmail-Status: Ham X-j-chkmail-Status: Ham Cc: bloat Subject: [Bloat] BitTorrent and IPv6 [was: tackling torrent...] X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 21 Jun 2015 15:32:42 -0000 [Removed AQM from CC.] > 4) *All* the traffic was udp. (uTP) Yes, modern BitTorrent implementations prefer µTP to TCP. Unfortunately, the implementation of µTP in Transmission doesn't perform PMTUD, and gets packet sizes wrong most of the time. (Yes, I spoke about this to Arvid. No, he wasn't particularly concerned.) > Despite ipv6 being enabled (with two source specific ipv6 ips), I did > not see any ipv6 peers connect. Bug? Death of torrent over ipv6? > Blocking? What? Please check that you allow incoming IPv6 to your peer, for both TCP and UDP. Obviously, setting port forwarding for IPv4 is not enough for that — you'll need to explicitly set up a hole in your IPv6 firewall. If using OpenWRT: config rule option target 'ACCEPT' option src 'wan' option name 'Transmission-v6' option family 'ipv6' option dest '*' option dest_port '12345' for the right value of 12345. If you set the logging level in Transmission to Debug and let it run for twenty minutes or so, you should see periodic "Starting IPv6 DHT announce (... good ...)". If you keep seeing "firewalled" instead of "good", you've got an issue. Once you're positive you don't have firewalling issues, the following might be of interest. I've done quite a bit of work a few years ago to improve IPv6 support in Transmission. The main problem is how to learn the IPv6 addresses of your peers: 1. Many trackers don't support IPv6. 2. IPv6 is supported by PEX (gossip, peer-exchange). I'm not sure if other peers honour IPv6 PEX when connected over IPv4, but Transmission certainly does. 3. I've implemented a protocol extension that allows peers connected over IPv4 to exchange their IPv6 addresses. This is only marginally useful, but can sometimes allow bootstrapping IPv6 PEX without tracker support. 4. Most importantly, I've implemented IPv6 support for the DHT (BEP-32) [1]. BEP-32 is now implemented by Transmission, Vuze, Tixati, KTorrent and Shareaza. Points (1) through (3) are interoperable with µTorrent/BitTorrent and libtorrent, which constitute the vast majority of deployed BitTorrent peers. Unfortunately, µTorrent and libtorrent do not implement BEP-32, and since these implementations constitute the vast majority of deployed BitTorrent peers outside China, this seriously limits the effectiveness of the IPv6 DHT. (Yes, I've spoken to the µTorrent developers, and while they reviewed BEP-32 favourably, they had no plans at the time to implement it.) [1] http://www.bittorrent.org/beps/bep_0032.html -- Juliusz