Re: [LARTC] R2Q and more

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

On Monday 29 March 2004 01:44, Roy wrote:
> > > Q2. What happens if the SUM of all the clients' class RATE
> (+
> > the
> >
> > > default class RATE) is bigger than 256kbit? Will HTB
>
> work
>
> > correctly?
> > Yes.
> > --------
> > This is incorrect:
> > of course it will work more or less, but nearly same as without
>
> any shaping
> It will work more then you think.  On the short term, traffic can be bursty
> for the different classes, but each one will belimited to 8kbit.  But on
> the long term, each class will get the same share of bandwidth.
> ------
> basicaly this may work if difference is not big,
There is one thing I learned: each setup and problem requires a different 
aproaches.  Sometimes, you can shape without being the bottlenek, sometimes 
you can"t.

> but it was not working for me, I was trying to set rate 8kbit for everyone,
> since the sum of rates was 3 times biger than parent ceil, trafic was
> divided in unpredictable way.
> then  I set rate to 1 kbit and everything worked well filling syslog by
> warnings that quantum is too small.
>
> logicaly this should not work because htb guarantee the rate amount trafic,
> so what if there is not so much available?
I 'm afraid the answer depends also on the client.  The client that pushes the 
most, will get the most.

> I'm not sure but, isn't quanum only used for leaf classes?  So the quantum
> of
> parent classes doesn't mather ?
> ---------
> You may be right, since I did not checked source code for this, but
> logicaly quantum is very significant part
> and shoud work everywhere, I suppose quantum is about same as cburst, but
> even more significant,
> sems  it is only way to divide bandwitch between classes with some
> proportion.
Quantum is only used if each child class is sending the configured rate and 
the parent class has some bandwidth left.  So if sum (rate of child classes) 
= parent rate, quantum is never used.  The class with the lowest prio will 
get the remaining bandwidth, so the configured rate is the minimum rate of a 
class.

> -----------------
> I found strange limitation, if class have leafs, then I cant attach sfq to
> it.
You can, but it will never be used.

> where will go unclasified packets from that class? Into root's default?
In previous versions, it hangs your system.  I think the packets are send in 
the :0 class, this is a passthru class.

Stef

-- 
stef.coene@docum.org
 "Using Linux as bandwidth manager"
     http://www.docum.org/
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