From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-la0-f97.google.com (mail-la0-f97.google.com [209.85.215.97]) (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 4E42F21F0BD for ; Mon, 27 Apr 2015 03:57:55 -0700 (PDT) Received: by labgd6 with SMTP id gd6so2188555lab.2 for ; Mon, 27 Apr 2015 03:57:53 -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=9aCr+lLzM9jLP34NKy8b7UAuN2kJAyme6fgp/69cDIs=; b=VA8K0dngP5Fy5+D8xkYfAW6QD7ney9ahtck1AEqjYJoNDthR2wbuRY95h5aEL86Xk8 t1SD4Bp3qfiMMz9NJApFT+Kq+H2AH+iRPguPYD0hQJsHCLucQvRnqp4E5XGhx4VRTQwC TaY3aQvY+j5P7pbtf9vptk07sydF+NdFMdfK+AR7nV/BUULXkEt79lLqxFjgF8OBM4i+ r+XmboWXb1spSr0o42CnhPl2v1BD/DA8xmEcF2c+piiZxVy+IMo1rziNPFuy8bqQr/0g pentvPe4cMoD+JrVXinnvFzFHtmfxybEMSVaQEwjoxwNls2q6MmJm7zw/Kvh423Yq1b4 tYWw== X-Gm-Message-State: ALoCoQnBmMIkUNWdaeK4i4q5On07LlwqnOxWnHEOuX+Tn6ijh85kmDxqnQUQ4VKECB839Fe1asZa6+lbfAHQA6DB7Hgc3H7LJg== X-Received: by 10.180.19.134 with SMTP id f6mr19361887wie.35.1430132273202; Mon, 27 Apr 2015 03:57:53 -0700 (PDT) Received: from mail.la.pnsol.com (eu1sys200aog112.obsmtp.com. [207.126.144.133]) by mx.google.com with SMTPS id bc1sm1158098wjc.1.2015.04.27.03.57.52 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Mon, 27 Apr 2015 03:57:53 -0700 (PDT) X-Relaying-Domain: pnsol.com Received: from mail.la.pnsol.com ([89.145.213.110]) (using TLSv1) by eu1sys200aob112.postini.com ([207.126.147.11]) with SMTP ID DSNKVT4WL+/uNS3CNw4MSXGV5rcEoq2YadQ3@postini.com; Mon, 27 Apr 2015 10:57:52 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 1YmgjU-0001Uw-KM; Mon, 27 Apr 2015 11:57:48 +0100 Received: from [172.20.5.110] by roam.smtp.pnsol.com with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:128) (Exim 4.82) (envelope-from ) id 1YmgjK-00008C-8a; Mon, 27 Apr 2015 10:57:38 +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: <877fsx3l5a.fsf@toke.dk> Date: Mon, 27 Apr 2015 11:57:53 +0100 Content-Transfer-Encoding: quoted-printable Message-Id: References: <72DB0260-F0DF-426F-A3F3-ECF5D8AF228F@pnsol.com> <877fsx3l5a.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 10:58:23 -0000 On 27 Apr 2015, at 11:45, Toke H=C3=B8iland-J=C3=B8rgensen = wrote: > Neil Davies writes: >=20 >> Take a look at http://www.pnsol.com/publications.html, you may find >> http://www.pnsol.com/public/PP-PNS-2009-02.pdf as a good starting >> point. >=20 > I've seen this referred on the list before (I assume by you ;)), but > haven't really grok'ed it before. I like the delta-Q measure as a way = of > thinking about overall network performance; and there's definitely > parallels to thinking about the end-to-end 'latency budget', which I > also find quite instructive (I think I it picked up from Joe Touch at > some point). You'll find the way that =E2=88=86Q can be decomposed into basis set of =E2=88=86Q|G, =E2=88=86Q|S and =E2=88=86Q|V - helps work out which parts = of the budget=20 get eaten up by different elements of the network design/architecture. >=20 > How do you deal with the fact that loss and delay can be exchanged for > each other (via retransmissions)? Yes, the QTA/=E2=88=86Q framework is recursive in that sense - you can = relate (for=20 example) the "TCP layer =E2=88=86Q" to the "IP packet level =E2=88=86Q". >=20 > Also, which publication would you recommend if I'm interested in > specifically how you 'Mathematically model behaviour and delta-Q' as = you > mention in that slide set? :) >=20 Depends on your starting point:=20 - if it is "how does this relate to the end user" - look at "the = properties and mathematics of data transport quality"=20 - if it is "how do I measure this stuff in a real network" - take a = look at "advanced network performance measurement techniques" (you can = get to it off the links tab) > -Toke Neil=