From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mailout-de.gmx.net (mailout-de.gmx.net [213.165.64.22]) by huchra.bufferbloat.net (Postfix) with SMTP id EA303201B88 for ; Tue, 4 Dec 2012 16:01:44 -0800 (PST) Received: (qmail invoked by alias); 05 Dec 2012 00:01:43 -0000 Received: from tsaolab-fw.caltech.edu (EHLO [192.168.50.1]) [131.215.9.89] by mail.gmx.net (mp016) with SMTP; 05 Dec 2012 01:01:43 +0100 X-Authenticated: #24211782 X-Provags-ID: V01U2FsdGVkX197pXBlMtV79XKJ+hIMhBL1L3JWLIjOmX7kzanD/u 0AaEGIchH1g+PD Mime-Version: 1.0 (Apple Message framework v1283) Content-Type: text/plain; charset=windows-1252 From: Sebastian Moeller In-Reply-To: <1354590837.29387.9.camel@ganymede.home> Date: Tue, 4 Dec 2012 16:01:33 -0800 Content-Transfer-Encoding: quoted-printable Message-Id: <5CE78C0D-0D20-42D5-96DE-365508056749@gmx.de> References: <20121123221842.GD2829@linux.vnet.ibm.com> <20121128172058.GB2474@linux.vnet.ibm.com> <20121202230635.GA16359@linux.vnet.ibm.com> <87obib5qf8.fsf@toke.dk> <1354550303.24281.103.camel@shinybook.infradead.org> <1354590837.29387.9.camel@ganymede.home> To: Dan Siemon X-Mailer: Apple Mail (2.1283) X-Y-GMX-Trusted: 0 Cc: codel@lists.bufferbloat.net, cerowrt-devel@lists.bufferbloat.net, bloat Subject: Re: [Cerowrt-devel] [Codel] FQ_Codel lwn draft article review X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 05 Dec 2012 00:01:45 -0000 Hi Dan, silly question, are you sure your ISP actually delivers PTM-TC instead = of ATM? (Should be easy to check, ATM carrier will show a "quantized" in = crease in ping time, increasing only every 48byte, but I guess you know = more about theses things than I do). Also what about simply empirically = increasing the overhead in your shaper until the anomaly goes away to = figure out whether this is simply a misjudged per packet overhead? And = then maybe the exact overhead value will give a clue about what is = happening there=85 best Sebastian On Dec 3, 2012, at 19:13 , Dan Siemon wrote: > On Mon, 2012-12-03 at 15:58 +0000, David Woodhouse wrote: >> ADSL is basically just ATM with a strange PHY. You have a bunch of >> options for how you use this ATM link. Mostly it's RFC2364 = PPP-over-ATM >> or it's PPPoE on top of RFC2684 Ethernet-over-ATM. >=20 > Speaking of xDSL, does anyone on the list happen to have a good > understanding of how much per-packet overhead there is on VDSL2? I've > been tweaking the buffering and shaping on my upstream link and = noticed > unexpected behavior with small packets. >=20 > The link below (use wayback machine version) has a good description of > per-packet overhead for various forms of ADSL but I haven't found > something similar for more modern DSL variants. > http://www.adsl-optimizer.dk/thesis/ > = http://web.archive.org/web/20090422131547/http://www.adsl-optimizer.dk/the= sis/ >=20 > I started a discussion on DSLReports > = http://www.dslreports.com/forum/r27565251-Internet-Per-packet-overhead-on-= Bell-s-VDSL-ATM-based- > but experimentally the overhead discussed there doesn't appear to be > correct > = http://www.coverfire.com/archives/2012/11/29/per-packet-overhead-on-vdsl2/= >=20 >=20 >=20 > _______________________________________________ > Codel mailing list > Codel@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/codel