From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-23-ewr.dyndns.com (mxout-041-ewr.mailhop.org [216.146.33.41]) by lists.bufferbloat.net (Postfix) with ESMTP id 089E32E02FC for ; Wed, 9 Feb 2011 07:50:28 -0800 (PST) Received: from scan-22-ewr.mailhop.org (scan-22-ewr.local [10.0.141.244]) by mail-23-ewr.dyndns.com (Postfix) with ESMTP id 7935B4507E for ; Wed, 9 Feb 2011 15:50:27 +0000 (UTC) X-Spam-Score: 0.0 () X-Mail-Handler: MailHop by DynDNS X-Originating-IP: 71.162.243.5 Received: from snark.thyrsus.com (static-71-162-243-5.phlapa.fios.verizon.net [71.162.243.5]) by mail-23-ewr.dyndns.com (Postfix) with ESMTP id B9EFB43B3D for ; Wed, 9 Feb 2011 15:50:23 +0000 (UTC) Received: by snark.thyrsus.com (Postfix, from userid 23) id D002A20C291; Wed, 9 Feb 2011 10:50:22 -0500 (EST) Date: Wed, 9 Feb 2011 10:50:22 -0500 From: Eric Raymond To: Bill Sommerfeld Message-ID: <20110209155022.GA13643@thyrsus.com> References: <20110205132305.GA29396@thyrsus.com> <20110208181811.GD7744@thyrsus.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: Eric Conspiracy Secret Labs X-Eric-Conspiracy: There is no conspiracy User-Agent: Mutt/1.5.20 (2009-06-14) Cc: bloat@lists.bufferbloat.net Subject: Re: [Bloat] First draft of complete "Bufferbloat And You" enclosed. X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list Reply-To: esr@thyrsus.com List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 09 Feb 2011 15:50:29 -0000 Bill Sommerfeld : > On Tue, Feb 8, 2011 at 10:18, Eric Raymond wrote: > > I don't understand "ack clocking". > > before you go any further, download and read the Van Jacobsen/Karels > paper "Congestion Avoidance and Control": > > ftp://ftp.ee.lbl.gov/papers/congavoid.ps.Z > > in a sliding-window protocol like TCP the arrival of an ack lets the > sender know that the receiver has buffer space for the next packet and > permits the sender to transmit more data; the acks form a kind of > "clock" that signals that data has left the network and that there is > room for more. Your summary is actually a more concise explanation of "ack clocking" than the paper offers, but thanks. Reading that was quite useful. I think I shall have to reread it a couple of times to grok in fullness, and expect the effort to be wll worthwhile. -- Eric S. Raymond