From owner-freebsd-net Fri Jun 9 13:14:45 2000 Delivered-To: freebsd-net@freebsd.org Received: from overcee.netplex.com.au (peter1.corp.yahoo.com [208.48.107.4]) by hub.freebsd.org (Postfix) with ESMTP id 2E72737C518 for ; Fri, 9 Jun 2000 13:14:33 -0700 (PDT) (envelope-from peter@netplex.com.au) Received: from netplex.com.au (localhost [127.0.0.1]) by overcee.netplex.com.au (Postfix) with ESMTP id 3D4DC1CE4; Fri, 9 Jun 2000 13:14:32 -0700 (PDT) (envelope-from peter@netplex.com.au) X-Mailer: exmh version 2.1.1 10/15/1999 To: Thierry Herbelot Cc: "Gary T. Corcoran" , Luigi Rizzo , net@FreeBSD.ORG Subject: Re: HEADS UP- WF2Q and RED now available in -current In-Reply-To: Message from Thierry Herbelot of "Thu, 08 Jun 2000 22:16:54 +0200." <393FFF36.BE411C54@cybercable.fr> Date: Fri, 09 Jun 2000 13:14:32 -0700 From: Peter Wemm Message-Id: <20000609201432.3D4DC1CE4@overcee.netplex.com.au> Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Thierry Herbelot wrote: > "Gary T. Corcoran" wrote: > > > > Luigi, > > > > > as the subject says, i have just committed some new code to > > > dummynet (and related hooks and documentation for ipfw) to > > > implement RED (thanks to Gianluca Iannaccone) and a > > > variant of Weighted Fair Queueing called WF2Q+ > > > > I checked your web page, but didn't find anything describing > > what "RED" is. And I'm afraid if I just put "red" into a > > search engine I'll get a zillion results... ;-) > > > > So could you just very briefly explain what "RED" is, and/or > > point me to a URL which describes it? > > Random Early Discard : if the channel has not enough bandwidth, just > throw away some frames (randomly) More to the point, it takes advantage of TCP backoff to slow down all the TCP sessions so that you don't quite get to the point of hitting the 100% limit and losing a large chunk of in-flight data. If you drop a few packets earlier you can "shape" the tcp connection(s) so that they don't hit the wall hard. Cheers, -Peter -- Peter Wemm - peter@FreeBSD.org; peter@yahoo-inc.com; peter@netplex.com.au "All of this is for nothing if we don't go to the stars" - JMS/B5 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message