[LARTC] help needed using filters

[LARTC] help needed using filters

[Abraham van der Merwe]

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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?

b) i'm confused be the parent x:y and flowid a:b terminology in the filter.
When do I use what?

-- 

Regards
 Abraham

Anyone can hold the helm when the sea is calm.
		-- Publius Syrus

___________________________________________________
 Abraham vd Merwe [ZR1BBQ] - Frogfoot Networks
 P.O. Box 3472, Matieland, Stellenbosch, 7602
 Cell: +27 82 565 4451 Http: http://www.frogfoot.net
 Email: abz@frogfoot.net


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Re: [LARTC] help needed using filters

[Stef Coene]

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

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Re: [LARTC] help needed using filters

[Abraham van der Merwe]

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Hi Stef!

> > 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.

Ok, so how do you do what I want to do in the example above using the TBF
queuing discipline? All the examples I've seen so far uses CBQ, but that is
not what I want since I don't want to specify the size of my
interface/bandwidth (which is not needed to shape networks).

I obviously need a classful queuing displine so that I can make lots of
sibling classes with filters attached to each one (with each filter's flowid
pointing to a tbf qdisc in that class), but the question then is which
queuing discipline should I use for this "container queueing discipline"?

> > 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.

Thanks. This helps a lot. 

-- 

Regards
 Abraham

QOTD:
	"My shampoo lasts longer than my relationships."

___________________________________________________
 Abraham vd Merwe [ZR1BBQ] - Frogfoot Networks
 P.O. Box 3472, Matieland, Stellenbosch, 7602
 Cell: +27 82 565 4451 Http: http://www.frogfoot.net
 Email: abz@frogfoot.net


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Re: [LARTC] help needed using filters

[Stef Coene]

> Ok, so how do you do what I want to do in the example above using the TBF
> queuing discipline? All the examples I've seen so far uses CBQ, but that is
> not what I want since I don't want to specify the size of my
> interface/bandwidth (which is not needed to shape networks).
Cbq needs to know the NIC bandwidth for the internal calculations.  If you 
have 10Mbit nic, you have to specify 10mbit.  This is just for the 
calculations.  Htb does not need this.  

> I obviously need a classful queuing displine so that I can make lots of
> sibling classes with filters attached to each one (with each filter's
> flowid pointing to a tbf qdisc in that class), but the question then is
> which queuing discipline should I use for this "container queueing
> discipline"?
You need to use htb or cbq for it.  And you don't need the tbf to throttle the 
bandwidth.  You can throttle the bandwidth of a class with htb or cbq itself.
The classes are not reponsible for sending the packets, it's the qdisc 
attached to them that do this job.  So all packets in the class, will get 
sended by the qdisc, so you don't need a filter to do this.

Stef

-- 

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

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