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 E971B21F316 for ; Wed, 4 Mar 2015 01:43:00 -0800 (PST) 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 t249gjEW007546; Wed, 4 Mar 2015 01:42:45 -0800 Date: Wed, 4 Mar 2015 01:42:45 -0800 (PST) From: David Lang X-X-Sender: dlang@asgard.lang.hm To: KK In-Reply-To: Message-ID: References: <473265656416337848@unknownmsgid> 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 , "aqm@ietf.org" , Vishal Misra Subject: Re: [Bloat] [aqm] the cisco pie patent and IETF IPR filing 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, 04 Mar 2015 09:43:29 -0000 On Wed, 4 Mar 2015, KK wrote: > Date: Wed, 04 Mar 2015 01:01:19 -0800 > From: KK > To: Vishal Misra , Dave Taht > Cc: "aqm@ietf.org" , bloat > Subject: Re: [aqm] the cisco pie patent and IETF IPR filing > > I think a combination of PI/PIE/fq_codel with ECN would enable us > a) be less dependent of the physical amount of buffering that is > implemented on the intermediate devices > b) allow us to use buffering for what it is meant to do - ride out > transient variations in traffic, at points where there is a mismatch in > available capacity The question is how much of a burst should the buffer be able to handle? Right now buffers routinely hold 10+ seconds worth of traffic (and Dave T showed the airline system buffering 10+ MINUTES of traffic) The problem is that if you buffer too much, you break the TCP link speed probing, and if you buffer even more you end up with the sender genrating a new packet to deliver while you still are buffering the old one. Buffers need to hold less than one second worth of traffic, and emperical testing is showing that much less is desirable (Others can post more exact numbers, but I belive that somewhere between 1/100 of a second and 1/10 of a second is a reasonable range) > c) allow us to support different types of links, including wireless lossy > links If a retry is fast and has a very high probability of succeding, then it may be worth holding it and doing a link-level retry. But the existing mess that is wifi is hardly a good example of this being the right thing to do in a congested environment. David Lang > d) as we wrote in the ECN RFC, allow even short-lived transfers to not > suffer > Thanks, >