From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lb0-x22c.google.com (mail-lb0-x22c.google.com [IPv6:2a00:1450:4010:c04::22c]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 7566A3B2A0; Mon, 18 Jan 2016 18:06:17 -0500 (EST) Received: by mail-lb0-x22c.google.com with SMTP id bc4so353380339lbc.2; Mon, 18 Jan 2016 15:06:17 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=content-type:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=umJDpuaqo/6SyxxdUnWNYx0hHtpsRvPmFa2cSZfg4Js=; b=p2OztsD2s0y3edIU4JaGdJ3Q3ERUw21D4zvg+BE8azknC2jLR2GZND5kw0/y4CLiYx 9iPXK8UzQlzTSh9IGL4vQ2ry2LjEto+brfZwv7GlyPKNF6x7TCTct9ZsKtLXL2El41IB WGvSg8DyU9yv2KYfJpVRMSzQzl9pxL/+jdEr0XG4UuDpkZLDAp9P0wk25+bZ/bIbLeU0 7jLj0awyUAwbD/K+DMEqaujjDHsYzu5wyyCEuNF3vs/uKWoV+aQCk9F1/ig9fSBe8+qH RU44r1H3/yLkZ03ZqG0jYSB2i07aS2VZYUIfLXxOCsALoETIX6seRCfIQXV1FGQk7RL4 ycFg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:content-type:mime-version:subject:from :in-reply-to:date:cc:content-transfer-encoding:message-id:references :to; bh=umJDpuaqo/6SyxxdUnWNYx0hHtpsRvPmFa2cSZfg4Js=; b=K+xPBPUT8QGQCvcP14+OQaDE7FRfRsmxU7QGY6a/e1mirhwDWUbY6Ud1M1Usiuub/Z O6vDk0ERD7CLaO0PAnpO6VVdhWC31vbvbF2y9LWfNZJ1YTFT1Sn3EESwVmpvZNKvtt/s R3M7zM8iTIXEwC6raVw5Bohf75fdJqLZ7HE3YB/XIFQN+wnocfRt8OqZhFp48RmAf579 QELDuTcXsfdqW2XURWOIyll+Q7KXOv2GrSjt49yrVJPdQzCSXiCug+I77C/3jMohTJVi Q4VpgDgDVkT5fIVH6dp2yDSQ9KVrtvxtweUg99l4dvhRinatDaICiRG7rrvmgFLeA+dQ 2acw== X-Gm-Message-State: AG10YOTjDAIc2CEy+nqSeQTHHxwUiJetV400ixbTmaFRohOSE7DkCk4OxWE1F8bZpyvVlg== X-Received: by 10.112.136.136 with SMTP id qa8mr8029095lbb.51.1453158376170; Mon, 18 Jan 2016 15:06:16 -0800 (PST) Received: from [192.168.238.201] (37-33-99-74.bb.dnainternet.fi. [37.33.99.74]) by smtp.gmail.com with ESMTPSA id 34sm3552965lfs.25.2016.01.18.15.06.15 (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 18 Jan 2016 15:06:15 -0800 (PST) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 9.2 \(3112\)) From: Jonathan Morton In-Reply-To: <23342.1453133686@dooku.sandelman.ca> Date: Tue, 19 Jan 2016 01:06:10 +0200 Cc: Valent Turkovic , "cerowrt-devel@lists.bufferbloat.net" , make-wifi-fast@lists.bufferbloat.net Content-Transfer-Encoding: quoted-printable Message-Id: <6ACF3DA5-AEA7-43DD-A3BA-33F680374F09@gmail.com> References: <6737994D-CE0B-46F5-B55C-A584FF6A8014@gmail.com> <23342.1453133686@dooku.sandelman.ca> To: Michael Richardson X-Mailer: Apple Mail (2.3112) Subject: Re: [Make-wifi-fast] [Cerowrt-devel] routers you can throw off the back of a truck 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: Mon, 18 Jan 2016 23:06:17 -0000 > On 18 Jan, 2016, at 18:14, Michael Richardson = wrote: >=20 > Jonathan Morton wrote: >> I haven=E2=80=99t yet found a robust way to automatically sense link = capacity from >> the upstream side. You=E2=80=99ll therefore need to set a = conservative static >> value for the uplink capacity. >=20 > As the maintainer of a PPPoE concentrator, and operator of some = networks, > I've been considering whether one can estimate the bandwidth using = round > trip PPP IPCP keep alives. Clearly, if both ends participate in time > stamping then it is much better, but I've been wondering if we can do = some > incremental deployment on one side or the other. >=20 > Sadly, I mostly just think about this while cycling; I haven't written = any > code yet. In most PPPoE deployments I know about, there is also a modem from which = the actual, precise link rates can usually be queried. Where that=E2=80=99= s not the case, IPCP (or is it LPCP?) probes would be a reasonable = workaround, but it must still be understood that the signal it provides = is only valid under saturating traffic, which complicates = implementation. - Jonathan Morton