Re: [LARTC] how to get the latency down on maxed out classes?

[Stef Coene <stef.coene@docum.org>]

On Saturday 07 December 2002 17:49, Abraham van der Merwe wrote:
> Hi Stef!
>
> > > Does anybody have any idea how to get the latency down and still
> > > maintain the correct throughput?
> >
> > If you want low latency for some traffic (ping, telnet, ssh), then you
> > can create a separate class for it.
> > And if you have a 64kbit modem, you have to be sure you never send more
> > data then the modem can handle.  If you send more data, the hugh modem
> > queue's will be filled so they create a lot of latency.  So for a 64kbit
> > link, try to limit ALL traffic to 60kbit so the queue's of the modem are
> > never filled.
>
> I'm doing all my tests under ideal conditions (over 100mbit lan and shaping
> the traffic to something low such as 384kbit). The problem is that the
> latency becomes unnatural.
>
> If you have a normal line, e.g. 64kbit and you saturate the line, the
> latency still stays within limits, but with HTB, the latency can become
> very high if you have multiple concurrent tcp sessions going at full steam
> in a class. I can understand why it does this, but I need a way to get the
> latency down to acceptable limits.
The only thing where I can think of, is adding a small fifo to each class.  
But you already tried and it created packets loss.  So I can't help you.

Stef

-- 

stef.coene@docum.org
 "Using Linux as bandwidth manager"
     http://www.docum.org/
     #lartc @ irc.oftc.net

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