From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stef Coene Date: Fri, 29 Nov 2002 18:36:07 +0000 Subject: Re: [LARTC] Best way to limit the rate Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lartc@vger.kernel.org On Friday 29 November 2002 14:10, Mathieu Deziel wrote: > Suppose you need to limit the rate of the traffic that flows in an HTB > leaf class to 32kbits/sec > > I can think of three ways to do it: > > 1. > make rate = ceil = 32kbit when creating this HTB leaf class. A pfifo > qdisc can then be attached to this HTB leaf class to reduce the queue > size, and therefore reduce the latency of the packets. > > 2. > Attach a TBF qdisc to this HTB leaf class, and configure it properly. HTB _is_ TBF. So the first idea is better. A ceiled htb class = tbf qdisc. > 3. > Have a policing filter before the HTB leaf class that will limit the > rate of the traffic before it enters the HTB leaf class. > > Which one of these methods is the best? > My tests have shown that the latency of the packets is dramatically > better with method 3. Anybody has an idea why this is the case? Solution 3 has the advantage that you limit the packet at a rate, but you don't have a queue. The policer uses a small tbf queue to limit the packets. The packets are simply dropped if they exceed a certain rate. It's also not possible to share bandwidth like you can do with cbq/htb. Stef -- stef.coene@docum.org "Using Linux as bandwidth manager" http://www.docum.org/ #lartc @ irc.oftc.net _______________________________________________ LARTC mailing list / LARTC@mailman.ds9a.nl http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/