From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefano Salsano Subject: Re: [RFC] netem: correlated loss generation (v3) Date: Thu, 20 May 2010 00:52:00 +0200 Message-ID: <4BF46B90.1000806@uniroma2.it> References: <4BD84428.30904@uniroma2.it> <20100517205621.036a06e0@nehalam> <20100519214239.GD5146@nuttenaction> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Stephen Hemminger , David Miller , Fabio Ludovici , netdev@vger.kernel.org, netem@lists.linuxfoundation.org To: Hagen Paul Pfeifer Return-path: Received: from smtp.uniroma2.it ([160.80.6.16]:54783 "EHLO smtp.uniroma2.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751881Ab0ESXMJ (ORCPT ); Wed, 19 May 2010 19:12:09 -0400 In-Reply-To: <20100519214239.GD5146@nuttenaction> Sender: netdev-owner@vger.kernel.org List-ID: Hagen Paul Pfeifer wrote: > * Stephen Hemminger | 2010-05-17 20:56:21 [-0700]: > > Why mainline? I questioning the advantage for the big audience, it looks like > a academic only piece of software - correct me if I'm wrong. > as an author, I can only give a "biased" point of view... anyway our work started from a cooperation with an industry which needed to test its solutions for fax/modem over IP under correlated loss. When we put our first version on the netem list, we were asked by people from another industry to add the feature of loss patterns coming out from a deterministic table. So my opinion is that the need to emulate "correlated" loss patterns is not academic, but it is a real need from industry... of course we can debate if it is a "niche" requirement or not > The authors pointed to some weak points in the implementation of the current > loss/correlation logic. But this "fix", add another - complicated component - > and let the broken components untouched ... Leaving or removing the broken component is an independent issue. May be we should allow to use the old syntax like this: tc qdisc change dev wlan0 root netem loss 2 because it was working OK, and we should disallow to use the old model in this way: tc qdisc change dev wlan0 root netem loss 2 10 because this produces broken results... BR, Stefano > > HGN > -- ******************************************************************* Stefano Salsano Dipartimento Ingegneria Elettronica Universita' di Roma "Tor Vergata" Via del Politecnico, 1 - 00133 Roma - ITALY http://netgroup.uniroma2.it/Stefano_Salsano/ E-mail : stefano.salsano@uniroma2.it Cell. : +39 320 4307310 Office : (Tel.) +39 06 72597770 (Fax.) +39 06 72597435 *******************************************************************