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 C172221F309 for ; Wed, 20 Aug 2014 23:56:16 -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 s7L6uE8s015495; Wed, 20 Aug 2014 23:56:14 -0700 Date: Wed, 20 Aug 2014 23:56:14 -0700 (PDT) From: David Lang X-X-Sender: dlang@asgard.lang.hm To: Jim Gettys In-Reply-To: Message-ID: References: <91696A3A-EF44-4A1A-8070-D3AF25D0D9AC@netapp.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: MULTIPART/Mixed; BOUNDARY="===============3804167707955082607==" Cc: bloat Subject: Re: [Bloat] sigcomm wifi 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: Thu, 21 Aug 2014 06:56:17 -0000 This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --===============3804167707955082607== Content-Type: TEXT/Plain; format=flowed; charset=UTF-8 Content-Transfer-Encoding: 8BIT On Wed, 20 Aug 2014, Jim Gettys wrote: > On Wed, Aug 20, 2014 at 3:12 AM, Eggert, Lars wrote: > >> On 2014-8-19, at 18:45, Dave Taht wrote: >>> I figured y'all would be bemused by the wifi performance in the sigcomm >>> main conference room this morning... >>> >>> http://snapon.lab.bufferbloat.net/~d/sigcomm_tuesday.png >> >> There is a reason we budgeted a 1G uplink for SIGCOMM Helsinki and made >> sure we had sufficient AP coverage... >> > > ​And what kinds of AP's? All the 1G guarantees you is that your bottleneck > is in the wifi hop, and they can suffer as badly as anything else > (particularly consumer home routers). > > The reason why 802.11 works ok at IETF and NANOG is that: > o) they use Cisco enterprise AP's, which are not badly over buffered. I > don't have data on which enterprise AP's are overbuffered. > o) they do a good job of placing the AP's, given a lot of experience > o) they turn on RED in the router, which, since there is a lot of > aggregated traffic, can actually help rather than hurt, and keep TCP > decently policed. > o) they play some interesting diffserv marking tricks to prioritize some > traffic, getting part of the effect the fq_codel gives you in its "new > flow" behavior by manual configuration. Fq_codel does much better without > having to mess around like this. > > Would be nice if they (the folks who run the IETF network) wrote a BCP on > the topic; I urged them some IETF's ago, but if others asked, it would help. > > If you try to use consumer home routers running factory firmware and hack > it yourself, you will likely lose no matter what you backhaul is (though > you might do ok using current CeroWrt/OpenWrt if you know what you are > doing. Yep, bad AP setup, coverage and configuration can cripple you. how many people in the room? David Lang --===============3804167707955082607== Content-Type: TEXT/PLAIN; CHARSET=us-ascii Content-ID: Content-Description: Content-Disposition: INLINE _______________________________________________ Bloat mailing list Bloat@lists.bufferbloat.net https://lists.bufferbloat.net/listinfo/bloat --===============3804167707955082607==--