From owner-freebsd-ipfw@FreeBSD.ORG Tue Nov 23 15:46:33 2010 Return-Path: Delivered-To: freebsd-ipfw@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 4A4991065674 for ; Tue, 23 Nov 2010 15:46:33 +0000 (UTC) (envelope-from luigi@onelab2.iet.unipi.it) Received: from onelab2.iet.unipi.it (onelab2.iet.unipi.it [131.114.59.238]) by mx1.freebsd.org (Postfix) with ESMTP id 0F5818FC27 for ; Tue, 23 Nov 2010 15:46:33 +0000 (UTC) Received: by onelab2.iet.unipi.it (Postfix, from userid 275) id 431AD73098; Tue, 23 Nov 2010 16:41:55 +0100 (CET) Date: Tue, 23 Nov 2010 16:41:55 +0100 From: Luigi Rizzo To: nangergong Message-ID: <20101123154155.GC48018@onelab2.iet.unipi.it> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.3i Cc: freebsd-ipfw@freebsd.org Subject: Re: Understanding of "mask" X-BeenThere: freebsd-ipfw@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: IPFW Technical Discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 23 Nov 2010 15:46:33 -0000 On Tue, Nov 23, 2010 at 02:19:02PM +0000, nangergong wrote: > Hi, all, > > I don't understand the meaning of "mask", > for example, in the following statements: > -------------------------------------- > ipfw pipe 1 config delay 80ms mask all > ipfw add 600 pipe 1 ip from 9.161.150.55 to 9.161.148.72 > ---------------------------------------- > > What is the usage of "mask all"? > I think in total there is only 1 queue, so "mask all" here doesn't make any mask tells ipfw to create as many actual pipes (and queues) as there are different values of the 5-tuple after masking. E.g. for a pipe with bw limitations (say bw 100Kbit/s) each flow would get its own 100Kbit/s without interference from the others. In this case the mask is useless because the pipe has only delay so there would be no interference anyways. cheers luigi