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 7A12E21F32C for ; Wed, 28 May 2014 11:45:03 -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 s4SIiq5c013962; Wed, 28 May 2014 11:44:52 -0700 Date: Wed, 28 May 2014 11:44:52 -0700 (PDT) From: David Lang X-X-Sender: dlang@asgard.lang.hm To: Hagen Paul Pfeifer In-Reply-To: Message-ID: References: <6A1B2B32-DC32-41D8-9BA3-57E28DD18F64@pnsol.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: bloat@lists.bufferbloat.net Subject: Re: [Bloat] ipspace.net: "QUEUING MECHANISMS IN MODERN SWITCHES" 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: Wed, 28 May 2014 18:45:03 -0000 On Tue, 27 May 2014, Hagen Paul Pfeifer wrote: > The question is if (codel/pie/whatever) AQM makes sense at all for > 10G/40G hardware and higher performance irons? Igress/egress bandwidth > is nearly identical, a larger/longer buffering should not happen. Line > card memory is limited, a larger buffering is defacto excluded. what if your router has more than two 40G interfaces? then you can have traffic patters where traffic inbound on connections #1 and #2 are trying to go out #3 at a rate higher than it can handle. At that point, you have two options 1. drop the packets 2. buffer them and hope that this is a temporary spike if you buffer them, then the question of what queuing to use, simple FIFO, codel, or ??? as well as how large the buffer should be allowed to grow before you start dropping (at which point, which packets do you drop) So I think that even on such big iron devices, there is room for the same sort of queueing options as for lower speed connections, but processor speed and memory size may limit how much you can do. David Lang