From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-11-ewr.dyndns.com (mxout-107-ewr.mailhop.org [216.146.33.107]) by lists.bufferbloat.net (Postfix) with ESMTP id 485D62E020F for ; Wed, 16 Feb 2011 09:46:46 -0800 (PST) Received: from scan-12-ewr.mailhop.org (scan-12-ewr.local [10.0.141.230]) by mail-11-ewr.dyndns.com (Postfix) with ESMTP id 9E92492A5C4 for ; Wed, 16 Feb 2011 17:46:45 +0000 (UTC) X-Spam-Score: 0.0 () X-Mail-Handler: MailHop by DynDNS X-Originating-IP: 66.252.224.242 Received: from brevard.conman.org (brevard.conman.org [66.252.224.242]) by mail-11-ewr.dyndns.com (Postfix) with ESMTP id 7C26C92ED58 for ; Wed, 16 Feb 2011 17:46:44 +0000 (UTC) Received: by brevard.conman.org (Postfix, from userid 500) id BCBC94F68976; Wed, 16 Feb 2011 12:46:27 -0500 (EST) Date: Wed, 16 Feb 2011 12:46:27 -0500 From: Sean Conner To: bloat@lists.bufferbloat.net Message-ID: <20110216174627.GA20215@brevard.conman.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4.1i Subject: [Bloat] Background Bufferbloat Detector 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, 16 Feb 2011 17:46:46 -0000 I've been thinking about this background bufferbloat detector, and I am wondering why you are bothering with NTP? I understand about the timestamps, but wouldn't it be easier if you had a program that sent packets at a known fixed rate? I wrote a simple program that sends a UDP packet every 20ms; the receiver (same program, different options) records when it received the packet (which should be 20ms since the last packet received). It then records the actual delta to a file (which can later be graphed). Running it I do see variations in the timings; I'm wondering if what I did is actually relevent to detecting bufferbloat? -spc (Also, just to mention: it can be used on an IPv6 network, and can handle multicast addresses for sending and receiving)