From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from eu1sys200aog107.obsmtp.com (eu1sys200aog107.obsmtp.com [207.126.144.123]) (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 75CB1202761; Thu, 10 May 2012 08:35:13 -0700 (PDT) Received: from mail.la.pnsol.com ([89.145.213.110]) (using TLSv1) by eu1sys200aob107.postini.com ([207.126.147.11]) with SMTP ID DSNKT6vgH3GAseZ6en62ax0PjWLqTUKjEzAB@postini.com; Thu, 10 May 2012 15:35:14 UTC Received: from [172.20.5.166] by mail.la.pnsol.com with esmtp (Exim 4.63) (envelope-from ) id 1SSVOI-0004rt-2i; Thu, 10 May 2012 16:34:54 +0100 Mime-Version: 1.0 (Apple Message framework v1257) Content-Type: text/plain; charset=us-ascii From: Neil Davies In-Reply-To: <1336660932.27520.152.camel@shinybook.infradead.org> Date: Thu, 10 May 2012 16:34:53 +0100 Content-Transfer-Encoding: quoted-printable Message-Id: References: <532BA404-30FF-4395-9575-709A68E4C723@gmail.com> <1336631707.27520.136.camel@shinybook.infradead.org> <1336633359.27520.147.camel@shinybook.infradead.org> <1336660932.27520.152.camel@shinybook.infradead.org> To: David Woodhouse X-Mailer: Apple Mail (2.1257) X-Mailman-Approved-At: Thu, 10 May 2012 08:57:58 -0700 Cc: codel@lists.bufferbloat.net, bloat Subject: Re: [Codel] [Bloat] The challenge X-BeenThere: codel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: CoDel AQM discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 10 May 2012 15:35:15 -0000 Bit unfair to BT... BT have architected their network so that cells loss doesn't happen.=20 They pace the cell rate, on a per line basis, in their BRASs so that=20 individual DSLAM buffers are not overrun. The PPP sessions are terminated in BT's BRAS - the ISPs LNS establishes an L2TP tunnel to the BRAS.=20 As for the sanity, we've measured other ISPs in the UK. They deliver = consistently more jitter and loss than BT's *wholesale* network. Neil On 10 May 2012, at 15:42, David Woodhouse wrote: > On Thu, 2012-05-10 at 10:25 -0400, Justin McCann wrote: >> Can't they turn on Early Packet Discard or something similar? This >> seems like a no-brainer.=20 >=20 > This is British Telecom we're talking about. >=20 > No, we cannot expect them to do *anything* even half sane. >=20 > The ISP has clue, and the PPP session handled by BT's DSLAM is > terminated in an L2TP session on their LNS. For the foreseeable = future, > that is where any queue management has to happen. >=20 > --=20 > dwmw2 > _______________________________________________ > Bloat mailing list > Bloat@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/bloat