From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH] netem: add cell concept to simulate special MAC behavior Date: Mon, 12 Dec 2011 19:45:12 -0500 (EST) Message-ID: <20111212.194512.338764506478752885.davem@davemloft.net> References: <20111212.190132.2127710068935598402.davem@davemloft.net> <1323736200-1252-1-git-send-email-hagen@jauu.net> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, fw@strlen.de To: hagen@jauu.net Return-path: Received: from shards.monkeyblade.net ([198.137.202.13]:41776 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753420Ab1LMApU (ORCPT ); Mon, 12 Dec 2011 19:45:20 -0500 In-Reply-To: <1323736200-1252-1-git-send-email-hagen@jauu.net> Sender: netdev-owner@vger.kernel.org List-ID: From: Hagen Paul Pfeifer Date: Tue, 13 Dec 2011 01:30:00 +0100 > This extension can be used to simulate special link layer > characteristics. Simulate because packet data is not modified, only the > calculation base is changed to delay a packet based on the original > packet size and artificial cell information. > > packet_overhead can be used to simulate a link layer header compression > scheme (e.g. set packet_overhead to -20) or with a positive > packet_overhead value an additional MAC header can be simulated. It is > also possible to "replace" the 14 byte Ethernet header with something > else. > > cell_size and cell_overhead can be used to simulate link layer schemes, > based on cells, like some TDMA schemes. Another application area are MAC > schemes using a link layer fragmentation with a (small) header each. > Cell size is the maximum amount of data bytes within one cell. Cell > overhead is an additional variable to change the per-cell-overhead > (e.g. 5 byte header per fragment). > > Example (5 kbit/s, 20 byte per packet overhead, cell-size 100 byte, per > cell overhead 5 byte): > > tc qdisc add dev eth0 root netem rate 5kbit 20 100 5 > > Signed-off-by: Hagen Paul Pfeifer > Signed-off-by: Florian Westphal > Acked-by: Stephen Hemminger Applied, thanks.