Re: [LARTC] help needed using filters

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

On Saturday 16 November 2002 19:34, Abraham van der Merwe wrote:
> Hi!
>
> I'm trying to shape a traffic to/from a few different subnets using TBF.
> The way I understand it all I have to do is create a few queueing
> disciplines and attach a filter to each queueing discipline.
>
> So for instance if I want to shape traffic going to 192.168.1.0/24 via eth0
> to 64kbit then it should look like this:
>
> ------------< snip <------< snip <------< snip <------------
> tc qdisc add dev eth0 root handle 1:0 tbf rate 64kbit burst 4kb latency
> 100ms peakrate 128kbit mtu 1500
>
> tc filter add dev eth0 parent 1:0 protocol ip prio 1 u32 match ip dst
> 192.168.1.0/24
> ------------< snip <------< snip <------< snip <------------
>
> I can't add the filter above and I suspect it is due to
>
> a) i can't add filters to tbf queueing disciplines? if so, why not?
Because the tbf qdisc is classless.  And filter are used to put packets in a 
child class.  CBQ/HTB are examples of classfull qdiscs.
You add a tbf qdisc as the root qdisc.  The root qdisc contains ALL packets 
that are sended.  So you don't need filters.

> b) i'm confused be the parent x:y and flowid a:b terminology in the filter.
> When do I use what?
Parent is the class where you add the filter.  If you have class 10:1 and you 
want to add a filter to class 10:1, you have to use parent 10:1.
When the filter matches a packet, it's placed in the class you specify with 
flowid.  If you have class 10:1 with class 10:10 attached to it and you want 
to redirect packets to it, you have to specify "parent 10:1 flowid 10:10" in 
the filter command.

Stef

-- 

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

_______________________________________________
LARTC mailing list / LARTC@mailman.ds9a.nl
http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/