From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from uplift.swm.pp.se (ipv6.swm.pp.se [IPv6:2a00:801::f]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 179483B2A4; Wed, 13 Dec 2017 05:20:37 -0500 (EST) Received: by uplift.swm.pp.se (Postfix, from userid 501) id 53CE7B2; Wed, 13 Dec 2017 11:20:35 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=swm.pp.se; s=mail; t=1513160435; bh=O+B09CzJ0HHsCXSHFBxB+iPrmswhpJJG0vb8C+Ro3Yw=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=luKjatt1p5AOfOJ7aAy/qhzVPSH3uOdZs2eY4n0BoW/khE/9y/EDWB20o0brTU1VZ hb7g2mJSoimvER+HiHemhmdpkJL2HcCeMSGDtKxojS66t7WhmnBT1zqgCDmDE2nP5K 8BtX0AtcDdA2EjNdIafgTwaa7gTiL0J3Tko0h2R0= Received: from localhost (localhost [127.0.0.1]) by uplift.swm.pp.se (Postfix) with ESMTP id 4FE87B1; Wed, 13 Dec 2017 11:20:35 +0100 (CET) Date: Wed, 13 Dec 2017 11:20:35 +0100 (CET) From: Mikael Abrahamsson To: Jonathan Morton cc: "David P. Reed" , "cerowrt-devel@lists.bufferbloat.net" , bloat In-Reply-To: Message-ID: References: <87bmjff7l6.fsf_-_@nemesis.taht.net> <1512417597.091724124@apps.rackspace.com> <87wp1rbxo8.fsf@nemesis.taht.net> <1513119230.638732339@apps.rackspace.com> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) Organization: People's Front Against WWW MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Subject: Re: [Bloat] [Cerowrt-devel] DC behaviors today X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 13 Dec 2017 10:20:37 -0000 On Wed, 13 Dec 2017, Jonathan Morton wrote: > Occasionally, of course, practically everyone in the country wants to > tune into coverage of some event at the same time. More commonly, they > simply get home from work and school at the same time every day. That > breaks the assumptions behind pure statistical multiplexing, and > requires a greater provisioning factor. Reasonable operators have provisioning guidelines that look at actual usage, although they probably look at it in 5 minute averages and not millisecond as done here in this context. So they might say "if busy hour average is over 50% 3 days in a week" this will trigger a provisioning alarm for that link, and the person (or system) will take a more detailed look and look at 5minute average graph and decide if this needs to be upgraded or not. For me the interesting point is always "what's going on in busy hour of the day" and never "what's the monthly average transferred amount of data". Of course, this can hide subsecond bufferbloat extremely well (and has), but at least this is typically how statistical overprovisioning is done. You look at actual usage and make sure your network is never full for any sustained amount of time, in normal operation, and make sure you perform upgrades well before the growth has resulted in network being full. -- Mikael Abrahamsson email: swmike@swm.pp.se