From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH] tcp: Socket option to set congestion window Date: Wed, 26 May 2010 20:04:43 -0700 (PDT) Message-ID: <20100526.200443.232751390.davem@davemloft.net> References: <20100526212745.GC24615@basil.fritz.box> <20100526.151014.70204145.davem@davemloft.net> <20100526231512.GD2684@nuttenaction> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: andi@firstfloor.org, therbert@google.com, shemminger@vyatta.com, netdev@vger.kernel.org, ycheng@google.com To: hagen@jauu.net Return-path: Received: from 74-93-104-97-Washington.hfc.comcastbusiness.net ([74.93.104.97]:38030 "EHLO sunset.davemloft.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757566Ab0E0DEe (ORCPT ); Wed, 26 May 2010 23:04:34 -0400 In-Reply-To: <20100526231512.GD2684@nuttenaction> Sender: netdev-owner@vger.kernel.org List-ID: From: Hagen Paul Pfeifer Date: Thu, 27 May 2010 01:15:12 +0200 > How can a domain defined as {process,peer-IP} fair to the 1MB > bottleneck link? You're asking about a network level issue in terms of what can be done on a local end-node. All an end-node can do is abide by congestion control rules and respond to packet drops, as has been going on for decades. People have basically (especially in Europe) given up on crazy crap like RSVP and other forms of bandwidth limiting and reservation. They just oversubscribe their links, and increase their capacity as traffic increases dictate. It just isn't all that manageable to put people's traffic into classes and control what they do on a large scale. I'm also skeptical about those who say the fight belongs squarely at the end nodes. If you want to control the network traffic of the meeting point of your dumbbell, you'll need a machine there doing RED or traffic limiting. End-host schemes simply aren't going to work because I can just add more end-hosts to reintroduce the problem. The dumbbell situation is independant of the end-node issues, that's all I'm really saying.