From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-la0-f98.google.com (mail-la0-f98.google.com [209.85.215.98]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id B5A2721F1E4 for ; Mon, 27 Apr 2015 13:38:26 -0700 (PDT) Received: by lamq1 with SMTP id q1so2498006lam.1 for ; Mon, 27 Apr 2015 13:38:24 -0700 (PDT) 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=BG9BAmj2pCBO6yKsqnsnY58B6cv8Gi5IlxWO3OxC6ww=; b=RBFtDHUvQ4wgngwAqe+zFRaYc4ePhYMegv/tIRybcL4sW3BsXkbWEXe2rqXyYHvlFQ 0lfRAvOiJrDFuuT707qOrxuy9usCtDs/xV6EL2iXd0VtHInE3iLQIbu6Pf3eE/v24R0e UZ46xX4ZbabdfM/hSsTO6Y/a9gcU2fmq8Lm4fGoNjHGyFybW7/qjqRYREGrQsK61JMya 122+2epqoapyDMhUJYTAPMV23IJncaMuMM7MknOuwhPductulxNx5YimUJAHc9fJ+a99 OE/CZLHZzZCjF94SrCacbqo321fOnDECr/CJOYUkWvSUbn5S+oMwxp9RE5dQg/4XNMth e90Q== X-Gm-Message-State: ALoCoQmXLZ1c7xBhRa9dfsWW+KxlsknB7+1qZtkEqTJ89VCIQ4fHSMDlMkrkVgMWJ3cAbXBMHIxRYNiPvZrvDk1riqXZDcgQGg== X-Received: by 10.194.192.65 with SMTP id he1mr1471011wjc.118.1430167104504; Mon, 27 Apr 2015 13:38:24 -0700 (PDT) Received: from mail.la.pnsol.com (eu1sys200aog117.obsmtp.com. [207.126.144.143]) by mx.google.com with SMTPS id a9sm1238596wjy.2.2015.04.27.13.38.23 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Mon, 27 Apr 2015 13:38:24 -0700 (PDT) X-Relaying-Domain: pnsol.com Received: from mail.la.pnsol.com ([89.145.213.110]) (using TLSv1) by eu1sys200aob117.postini.com ([207.126.147.11]) with SMTP ID DSNKVT6ePm3pljD5uqIfPmq3KPaW+B1HYZ6u@postini.com; Mon, 27 Apr 2015 20:38:23 UTC Received: from git.pnsol.com ([172.20.5.238] helo=roam.smtp.pnsol.com) by mail.la.pnsol.com with esmtp (Exim 4.76) (envelope-from ) id 1YmpnH-00033p-1q; Mon, 27 Apr 2015 21:38:19 +0100 Received: from [172.20.5.109] by roam.smtp.pnsol.com with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:128) (Exim 4.82) (envelope-from ) id 1Ympn6-0000AE-QX; Mon, 27 Apr 2015 20:38:08 +0000 Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) From: Neil Davies In-Reply-To: <874mo11sdf.fsf@toke.dk> Date: Mon, 27 Apr 2015 21:38:21 +0100 Content-Transfer-Encoding: quoted-printable Message-Id: References: <72DB0260-F0DF-426F-A3F3-ECF5D8AF228F@pnsol.com> <877fsx3l5a.fsf@toke.dk> <874mo11sdf.fsf@toke.dk> To: =?utf-8?Q?Toke_H=C3=B8iland-J=C3=B8rgensen?= X-Mailer: Apple Mail (2.1878.6) Cc: bloat Subject: Re: [Bloat] Detecting bufferbloat from outside a node 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: Mon, 27 Apr 2015 20:38:55 -0000 Toke =E2=88=86Q is both the concept (quallity attenuation - the fact that = delay and potential for loss is both conserved and only every = increases[1]) and for its representation as an improper random variable = (one who's CDF doesn't necessarily reach one). One of my adages is that "network quality" doesn' t exist - just like = you can't buy a box of "dark" and make a room dark by opening the box, = you can't buy a box of "network quality" - delivering quality in = networks is managing (through bounding) the "quality attenuation" Neil [1] Delay and loss can be traded - i.e resends or even forward error = correction - but you can't reduce the =E2=88=86Q - resends mean = increased delay to cover loss, forward error correction means increased = delay to cover bit error rates) etc This is true at any (and all layers) = and in *every* queueing and scheduling mechanism, just one of those = nasty universal properties that we can't get away from. On 27 Apr 2015, at 16:51, Toke H=C3=B8iland-J=C3=B8rgensen = wrote: > Neil Davies writes: >=20 >> Depends on your starting point: >=20 > Right, having looked a bit more at this: >=20 >> - if it is "how does this relate to the end user" - look at "the >> properties and mathematics of data transport quality" >=20 > This mentions, on slide 30, an analytical model for predicting = (changes > in) =E2=88=86Q. Is this Judy Holyer's "A Queueing Theory Model for = Real Data > Networks", or does it refer to something else? >=20 > -Toke