From mboxrd@z Thu Jan 1 00:00:00 1970 From: George Nychis Subject: Re: want to randomly drop packets based on percent Date: Mon, 17 Apr 2006 19:08:16 -0400 Message-ID: <44441FE0.6080908@cmu.edu> References: <444345F9.4090100@cmu.edu> <20060417091915.67e28361@localhost.localdomain> <4444171B.90507@cmu.edu> <20060417094634.7191fea5@localhost.localdomain> <4443CAD1.9050701@cmu.edu> <20060417103211.24115952@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org Return-path: Received: from smtp.andrew.cmu.edu ([128.2.10.82]:25312 "EHLO smtp.andrew.cmu.edu") by vger.kernel.org with ESMTP id S1750705AbWDQXIU (ORCPT ); Mon, 17 Apr 2006 19:08:20 -0400 To: Stephen Hemminger In-Reply-To: <20060417103211.24115952@localhost.localdomain> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Stephen Hemminger wrote: >O > > >>>>>>I wanted to insert artificial packet loss based on a percent so i found: >>>>>>network emulab qdisc could do it, so i compiled support into the kernel >>>>>>and tried: >>>>>>tc qdisc change dev eth0 root netem loss .1% >>>>>> >>>>>> >>>>>> >>>>>> >>> ^^^^^^ >>> >>>You need to do add not change. Add will set the queue discipline >>>to netem (default is pfifo_fast). Change is for changing netem parameters >>>after it is loaded. >>> >>> >>> >>> >>> >>bahhh I see... the wiki has "change" instead of add. Now i'm running >>into another problem, I have an XCP qdisc that I have already added via: >>tc qdisc add dev ath0 root xcp capacity 54Mbit size 500 >> >> >> > >Wiki reads as a set of examples. First uses, "add" after that "change". > > > > >>therefore when I also try to incorperate loss: >>tcq disc add dev ath0 root netem loss .1% >> >>I get: >>RTNETLINK answers: File exists >> >>Is it possible to use two qdiscs on the same interface? >> >> >> > >No, but netem is "classful" so you can put xcp inside netem. >Look at the token bucket example on the wiki. > > > Sorry, I was looking at the LARTC guide, completely skipped over the blatently obvious block of commands you were pointing me too :P Thanks! George