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/
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