From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bifrost.lang.hm (mail.lang.hm [64.81.33.126]) (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 D58FC21F352; Thu, 11 Jun 2015 18:44:53 -0700 (PDT) Received: from asgard.lang.hm (asgard.lang.hm [10.0.0.100]) by bifrost.lang.hm (8.13.4/8.13.4/Debian-3) with ESMTP id t5C1igYV025685; Thu, 11 Jun 2015 18:44:42 -0700 Date: Thu, 11 Jun 2015 18:44:42 -0700 (PDT) From: David Lang X-X-Sender: dlang@asgard.lang.hm To: Sebastian Moeller In-Reply-To: Message-ID: References: <5578DEE8.6090209@gmail.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: cake@lists.bufferbloat.net, Alan Jenkins , Daniel Havey , "cerowrt-devel@lists.bufferbloat.net" , bloat Subject: Re: [Cerowrt-devel] [Bloat] [Cake] active sensing queue management 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, 12 Jun 2015 01:45:22 -0000 On Thu, 11 Jun 2015, Sebastian Moeller wrote: > > On Jun 11, 2015, at 03:05 , Alan Jenkins wrote: > >> On 10/06/15 21:54, Sebastian Moeller wrote: >> >> One solution would be if ISPs made sure upload is 100% provisioned. Could be >> cheaper than for (the higher rate) download. > > Not going to happen, in my opinion, as economically unfeasible for a > publicly traded ISP. I would settle for that approach as long as the ISP is > willing to fix its provisioning so that oversubscription episodes are > reasonable rare, though. not going to happen on any network, publicly traded or not. The question is not "can the theoretical max of all downstream devices exceed the upstream bandwidth" because that answer is going to be "yes" for every network built, LAN or WAN, but rather "does the demand in practice of the combined downstream devices exceed the upstream bandwidth for long enough to be a problem" it's not even a matter of what percentage are they oversubscribed. someone with 100 1.5Mb DSL lines downstream and a 50Mb upstream (30% of theoretical requirements) is probably a lot worse than someone with 100 1G lines downstream and a 10G upstream (10% of theoretical requirements) because it's far less likely that the users of the 1G lines are actually going to saturate them (let alone simultaniously for a noticable timeframe), while it's very likely that the users of the 1.5M DSL lines are going to saturate their lines for extended timeframes. The problem shows up when either usage changes rapidly, or the network operator is not keeping up with required upgrades as gradual usage changes happen (including when they are prevented from upgrading because a peer won't cooperate) As for the "100% provisioning" ideal, think through the theoretical aggregate and realize that before you get past very many layers, you get to a bandwidh requirement that it's not technically possible to provide. David Lang