Re: [LARTC] How to use tc to limit bandwidth of a special IP in LAN

[Stef Coene <stafke@iname.com>]

Ramin Alidousti wrote:
> 
> Thanks Stef :-)
> 
> On Fri, Jun 15, 2001 at 07:57:12AM +0200, Stef Coene wrote:
> 
> > - allot 1514 cell 8 maxburst 10 avpkt 1000 : forget these options for
> > now, just set them
> 
> That's exactly what I meant.
> 
> > - split 1:0 defmap c0 :  ? ? ? ? Maybe to split the traffic?  I never
> > needed this options, so I don't know what this mean.  Just forget this
> > option for now.
> 
> You will never need something when you don't know of its existance ;-)
> 
> > > A small note on all these options would have saved me a lot of guess-work.
> > Better? ;-)
> 
> Yes. Much better :-)
> 
> > > But anyway, don't take me wrong. I think that iproute2 is one of the coolest
> > > networking tools I've ever seen.
> > Me to, you can do great things with CBQ but it really sucks and is not
> > accurate enough.
> 
> Why do you need accuracy when you're doing "Traffic Engineering" ;-)
I did some tests : I tried to give 2 hosts a bandwidth og 128kbit/s. 
Host A needs 75% of this bandwidth and host B 25%.  They share the same
128kbit/s so they may borrow unused bandwidth.  The only way to do this
is to create a qdisc on a bounded class of 128kbit/s (I tried all other
things and this was the only way to get it working).  On this qdisc you
can attach 2 classes for the two hosts with appropriate optiones and it
works perfect.  Host A gets 75% of the bandwidth and they can borrow
bandwidth. 
BUT, the problem is the bounded class and qdisc.  I did some tests and
CBQ is very bad when it has to bound a class, but the problem is that
you need a bounded class with his rate equal to the link-bandwidth.  You
can find some nice pictures on my website and they are very clear
(http://users.belgacom.net/staf/qos/tests/cbq/bounded/bounded-accuracy.html):
CBQ is not accurate when bounding a class.  So it's working but not
accurate enough.  There are some other problems, but this the most
inportant.

So if anyone out there has other results or find a solution, plz let us
know.  I did a lot of testing and I'm surre I didn't made a mistake.  I
made all the possible combinations of options, and each time it was not
working like I wanted to.



-- 

Stef

More QOS info : http://users.belgacom.net/staf/

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