From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from nm10-vm1.access.bullet.mail.bf1.yahoo.com (nm10-vm1.access.bullet.mail.bf1.yahoo.com [216.109.114.208]) (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 EFCBE21F324 for ; Wed, 28 May 2014 10:29:17 -0700 (PDT) Received: from [66.196.81.157] by nm10.access.bullet.mail.bf1.yahoo.com with NNFMP; 28 May 2014 17:29:16 -0000 Received: from [98.139.221.159] by tm3.access.bullet.mail.bf1.yahoo.com with NNFMP; 28 May 2014 17:29:16 -0000 Received: from [127.0.0.1] by smtp119.sbc.mail.bf1.yahoo.com with NNFMP; 28 May 2014 17:29:16 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rogers.com; s=s1024; t=1401298156; bh=WYPLIwyHdwkmYxdsEEf8D7+LJ5JhSJ6Qv6UcNTf+FUQ=; h=X-Yahoo-Newman-Id:X-Yahoo-Newman-Property:X-YMail-OSG:X-Yahoo-SMTP:X-Rocket-Received:Message-ID:Date:From:Reply-To:User-Agent:MIME-Version:To:Subject:References:In-Reply-To:X-Enigmail-Version:Content-Type:Content-Transfer-Encoding; b=oouVd+xE0cGfsq64L+pv1oMOK4HCzc/JyidYKTVO58YufCHwRoGoGz/GtcCRuv7vRtyBnMo/AGrTC2u8OFnYktOv3Ao0LhbxweLXJRFX9RT7eZmoErnQpzWaS4rkhikU4fLzzWkT0dP69wzJDfPV7ElMBb2+DurmDHS+rwJZG4w= X-Yahoo-Newman-Id: 580995.15899.bm@smtp119.sbc.mail.bf1.yahoo.com X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: FtSTdegVM1l31wtB8s9F_Nr3CkNvjq5YGukVF.jDYsW.hSl _Ef9CFc27Pk2hRGszWa_kYNT93LfLbwuNNg44C_ZZGY6tsI5s6yqlCVRBqNg M18dI8wJLUH3jXom2BzOf9xoIVAca5K.xYckTndNLMshKnyHUHcGvHl6BkqG 8sqfYKAhqXWwxN2VrQ2r2pJEhzd0mgY1JOnXtlUP3n.mWcwdl4wCJURgrgaQ fDAeWeNfT2hzDHbgqXmAW_BYGyFtpuWmQORCnulUCmy4nyuiaAeCSSplo0as dnDkVE8AWHoiS81PnyY0a1TX.VznDusFmRgDofZE1TtvsUdI24MufcfDpJ5U Orei81.4cuTM8JpqUUZE9lIfPrkl2G_VaeM1EEKWOyENMWOblXReqWm.G8rq NeD_Yos9oAGifIsIdsQnsgDhOttLpxbBKoaRflrcqqfwbqJqXlppCFccf2mD AsJZOS00UKuc3o3a1_jyNO_2YsCls2XrYkT3I_BvtvBvgj_od9UHrdZZgvAt PoCFw2DueIOArXO7xEs6Ea8uFj.W5Nkuw91mp52IZqekZUUAYagn3GHTzuTe 6JoMjGTL7_pbQPEz6SPJShiSIXrq.qzU- X-Yahoo-SMTP: sltvjZWswBCRD.ElTuB1l9j6s9wRYPpuyTNWOE5oEg-- X-Rocket-Received: from [10.111.100.146] (davec-b@74.213.188.46 with plain [98.139.221.125]) by smtp119.sbc.mail.bf1.yahoo.com with SMTP; 28 May 2014 17:29:16 +0000 UTC Message-ID: <53861CEB.8060003@rogers.com> Date: Wed, 28 May 2014 13:29:15 -0400 From: David Collier-Brown User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 MIME-Version: 1.0 To: bloat@lists.bufferbloat.net References: In-Reply-To: X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Bloat] ipspace.net: "QUEUING MECHANISMS IN MODERN SWITCHES", > (Jonathan Morton) X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list Reply-To: davecb@spamcop.net List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 28 May 2014 17:29:18 -0000 On 05/28/2014 11:33 AM, Jonathan Morton wrote > It's a mathematical truth for any topology that you can reduce to a black box with one or more inputs and one output, which you call a "queue" and which *does not discard* packets. Non-discarding queues don't exist in the real world, of course. > > The intuitive proof is that every time you promote a packet to be transmitted earlier, you must demote one to be transmitted later. A non-FIFO queue tends to increase the maximum delay and decrease the minimum delay, but the average delay will remain constant. A niggle: people working in queuing theory* make the simplifying assumption that queues don't drop. When describing the real world, they talk of "defections", the scenario where a human arrives at the tail of the queue and "defects", either to another queue or to the exit door of the store! As you might guess, what I find intuitive the IP world finds wrong, and vice versa. --dave [* as opposed, perhaps, to queuing networks (:-)] -- David Collier-Brown, | Always do right. This will gratify System Programmer and Author | some people and astonish the rest davecb@spamcop.net | -- Mark Twain -- David Collier-Brown, | Always do right. This will gratify System Programmer and Author | some people and astonish the rest davecb@spamcop.net | -- Mark Twain