Re: [LARTC] htb ceiling

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

On Friday 05 April 2002 10:19, Gavin wrote:
> Hello,
>
> I'm using HTB (through htb.init :) and it's nearly perfect, but the CEIL
> directive seems to have no effect.
>
> The relevant lines are:
>
> tc qdisc add dev eth1 root handle 1 htb default 10 r2q 100
> tc class add dev eth1 parent 1: classid 1:2 htb rate 5Mbit burst 15k
> tc class add dev eth1 parent 1:2 classid 1:40 htb rate 256Kbit ceil 512Kbit
> burst 15k
> tc qdisc add dev eth1 parent 1:40 handle 40 sfq perturb 10
> tc filter add dev eth1 parent 1:0 protocol ip prio 100 u32 match ip dst
> 10.0.0.2 classid 1:40
>
>  - this allows 10.0.0.2 to download at 256Kbit, even when it is the only
> machine doing any downloading.  I can affect this speed by changing the
> $rate, but changing $ceil has no effect whatsoever.
The ceil will prevent 10.0.0.2 to download faster then 512 kbit.  The rate 
will say how much 10.0.0.2 can download compare to the other classes (so the 
other lines are also relevant :).  

As example : If you have a second class :
tc class add dev eth1 parent 1:2 classid 1:50 htb rate 256Kbit ceil 512Kbit
burst 15k
Then both classes will get 50% of the bandwidth if they are both downloading. 
 If they are alone, they can get the 512 Kbit.

Second example :
tc class add dev eth1 parent 1:2 classid 1:50 htb rate 128Kbit ceil 512Kbit
burst 15k
Class 1:50 and class 1:40 are downloading -> class 1:40 will get 256 * 
(512/(256+128)) = 341 kbit and class 1:50 : 128 * (512/(256+128)) = 171 Kbit 
(they will devide the bandwidth compared to the rates).

I hope you understand what you want I want to say and I hope it's an answer 
on your question :)

Stef

-- 

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