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 8FA0221F1CA for ; Wed, 9 Jan 2013 23:24:20 -0800 (PST) Received: from asgard (asgard.lang.hm [10.0.0.100]) by bifrost.lang.hm (8.13.4/8.13.4/Debian-3) with ESMTP id r0A7O3Se025532 for ; Wed, 9 Jan 2013 23:24:09 -0800 Received: from lang.hm (localhost [127.0.0.1]) by asgard (Postfix) with ESMTP id 0D72D1387AB for ; Tue, 8 Jan 2013 21:02:05 -0800 (PST) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Date: Tue, 08 Jan 2013 21:02:05 -0800 From: David Lang To: In-Reply-To: <20130109033920.C47B95B2B40@lawyers.icir.org> References: <20130109033920.C47B95B2B40@lawyers.icir.org> Message-ID: <12916ad96425700de4a1892ad43f90b1@lang.hm> X-Sender: david@lang.hm User-Agent: Roundcube Webmail/0.5.1 Subject: Re: [Bloat] Bufferbloat Paper 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, 10 Jan 2013 07:24:20 -0000 On Tue, 08 Jan 2013 22:39:20 -0500, Mark Allman wrote: >> > Note the paper does not work in units of *connections* in section >> 2, but >> > rather in terms of *RTT samples*. So, nearly 5% of the RTT >> samples add >> >>= 400msec to the base delay measured for the given remote (in the >> > "residential" case). >> >> Hmm, yes, I was wondering about this and was unable to fully grok >> it: >> what, exactly, is an RTT sample? :) > > One RTT measurement between the CCZ monitoring point and the remote > end > host. > >> Incidentally, are the data extraction scripts available somewhere? >> Might be worthwhile to distribute them as some kind of tool that >> people with interesting vantage points could apply to get useful >> data? > > Well, they are not readily available. I used a non-public extension > to > Bro (that is not mine) to get the RTT samples. So, that is a > sticking > point. And, then there is a ball of goop to analyze those. If folks > have a place they can monitor and are interested in doing so, please > contact me. I can probably get this in shape enough to give you. > But, > I doubt I'll be able to somehow package this for general consumption > any > time soon. I really like the idea of trying to measure latency by sniffing the network and watching the time for responses. If this can work then I think a lot of people would be willing to put a sniffer inline in their datacenter to measure this. How specialized is what you are running? can it be made into a single-use tool that just measures and reports latency? David Lang