From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net (mout.gmx.net [212.227.15.18]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mout.gmx.net", Issuer "TeleSec ServerPass DE-1" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id A4C9821F385; Fri, 20 Mar 2015 06:46:42 -0700 (PDT) Received: from u-089-d066.biologie.uni-tuebingen.de ([134.2.89.66]) by mail.gmx.com (mrgmx001) with ESMTPSA (Nemesis) id 0M8m7Q-1YeQMP0r9g-00CBPP; Fri, 20 Mar 2015 14:46:33 +0100 Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) Content-Type: text/plain; charset=windows-1252 From: Sebastian Moeller X-Priority: 3 In-Reply-To: Date: Fri, 20 Mar 2015 14:46:29 +0100 Content-Transfer-Encoding: quoted-printable Message-Id: References: <20150316203532.05BD21E2@taggart.lackof.org> <123130.1426635142@turing-police.cc.vt.edu> <15A0911A-E3B7-440A-A26B-C5E1489EA98B@viagenie.ca> <1426773234.362612992@apps.rackspace.com> <1426796961.194223197@apps.rackspace.com> <550BD7DB.3040408@orange.com> To: "David P. Reed" X-Mailer: Apple Mail (2.1878.6) X-Provags-ID: V03:K0:lj5kcnl0Se79NBnuF4fPf8ZY/doRIIR3Wyq+0OZiJac50RzLhFj dXlph/CjZz6nECbuLSXPS1IZMhnje9k1iuXyC/vSoLZkkpVoYL1kcOSTqoHw5443HS3IwFL L2M/rxx4arP9xnjjzT079iQyudXZ+eIirQhUN9/Ju/ODg/Mwc44hgLCXmuoc+kYX+ebqrq3 gHwiyAygQFqv7amv6bKMQ== X-UI-Out-Filterresults: notjunk:1; Cc: Greg White , bloat , "Livingood, Jason" , "cerowrt-devel@lists.bufferbloat.net" , MUSCARIELLO Luca IMT/OLN Subject: Re: [Cerowrt-devel] [Bloat] DOCSIS 3+ recommendation? 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: Fri, 20 Mar 2015 13:47:13 -0000 Hi David, On Mar 20, 2015, at 14:31 , David P. Reed wrote: > The mystery in most users' minds is that ping at a time when there is = no load does tell them anything at all about why the network connection = will such when their kid is uploading to youtube. But it does, by giving a baseline to compare the ping tim under = load against ;) >=20 > So giving them ping time is meaningless.=20 > I think most network engineers think ping time is a useful measure of = a badly bufferbloated system. It is not. >=20 > The only measure is ping time under maximum load of raw packets. Why raw packets? But yes I agree; I think =93ping=94 in this = discussion here is short hand for "latency measurement under load=94 = which writes a bit unwieldy. The typical speed tests are almost there as = they already perform (half of) the create maximum load requirement for = the additional measurements we need (as well as already measuring = unloaded latency, they all already report a =93ping=94 number back, but = that is best case RTT, so the baseline with which to compare the latency = under load number (well obviously both numbers should be measured = exactly the same)). Measuring latency under simultaneous saturation of = both up- and downlink would be even better, but measuring it during = simplex saturation should already give meaningful numbers. I think it would be great if speedtest sites could agree to = measure and report such a number, so that end customers had data to base = their ISP selection on (at least those fortunate few that actually have = ISP choice=85). >=20 > And that requires a way to test maximum load rtt. >=20 > There is no problem with that ... other than that to understand why = and how that is relevant you have to understand Internet congestion = control. =20 >=20 > Having had to testify before CRTC about this, I learned that most = access providers (the Canadian ones) claim that such measurements are = never made as a measure of quality, and that you can calculate expected = latency by using Little's lemma from average throughput. And that = dropped packets are the right measure of quality of service. >=20 > Ookla ping time is useless in a context where even the "experts" = wearing ties from the top grossing Internet firms are so confused. And = maybe deliberately misleading on purpose... they had to be forced to = provide any data they had about congestion in their networks by a = ruling during the proceeding and then responded that they had no data - = they never measured queueing delay and disputed that it mattered. The = proper measure of congestion was throughput. >=20 > I kid you not. >=20 > So Ookla ping time is useless against such public ignorance.=20 But, if people make their choice of (higher/ more expensive) = service tiers dependent on its behavior at =93capacity=94 as = approximated by a speedtest latency under (full) load test that would = make it much easier for ISPs to actually respond to it; even marketing = can realize that this can be monetized ;) Best Regards Sebastian [...]=