From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [PATCH v3 net-next 2/2] netem: add cell concept to simulate special MAC behavior Date: Thu, 1 Dec 2011 08:57:01 -0800 Message-ID: <20111201085701.02f885c5@nehalam.linuxnetplumber.net> References: <20111201082436.20f21e52@nehalam.linuxnetplumber.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: "Hagen Paul Pfeifer" , "Eric Dumazet" , To: "David Laight" Return-path: Received: from mail.vyatta.com ([76.74.103.46]:47054 "EHLO mail.vyatta.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755407Ab1LAQ5F (ORCPT ); Thu, 1 Dec 2011 11:57:05 -0500 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Thu, 1 Dec 2011 16:38:51 -0000 "David Laight" wrote: > > > One idea to do small delays at higher speed is to insert > > dummy pad frames into the device. > > It would mean generating garbage, but would allow for > > highly accurate fine grain delay. > > Not a good idea. > They would have to be sent to a known MAC address > otherwise all the ethernet switches would forward them > on all output ports. > > David > > Yes it would have to be a constant destination, not sure if there is a discard value in Ethernet protocol spec.