[LARTC] Changing Linux traffic control parameters on the fly

[LARTC] Changing Linux traffic control parameters on the fly

[Simone Leggio]

Hi all,

I'm executing some experiments in a test network and I have a doubt. It 
is possible to change linux traffic control parameters (say, for 
example, the bandwidth allocated to a flow, its ceiling rate in a HTB 
scheduler, its weight parameter in a CBQ scheduler and so on) while the 
flow is actually traversing a router?

An example: let's assume that a certain class has allocated a bandwidth 
of 500 kbit/sec. Can I change, say after 10 seconds, while the flow is 
still active, the bandwidth allocated to that class to 1 Mbit/sec?

I know there is the command tc qdisc change with which I can change the 
parameters for a qdisc, but how to use it? Launching after 10 seconds 
another tc script?
Any ideas?
Thank you,

	Simone.

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Re: [LARTC] Changing Linux traffic control parameters on the fly

[Stef Coene]

On Friday 28 March 2003 16:12, Simone Leggio wrote:
> Hi all,
>
> I'm executing some experiments in a test network and I have a doubt. It
> is possible to change linux traffic control parameters (say, for
> example, the bandwidth allocated to a flow, its ceiling rate in a HTB
> scheduler, its weight parameter in a CBQ scheduler and so on) while the
> flow is actually traversing a router?
>
> An example: let's assume that a certain class has allocated a bandwidth
> of 500 kbit/sec. Can I change, say after 10 seconds, while the flow is
> still active, the bandwidth allocated to that class to 1 Mbit/sec?
Yes.

> I know there is the command tc qdisc change with which I can change the
> parameters for a qdisc, but how to use it? Launching after 10 seconds
> another tc script?
I do that all the time.  I remove and add the cbq/htb qdisc again while I 
leave the traffic running.  
For allmost all results you can find on www.docum.org, I wrote some scripts.  
Most of the time, I have a script that creates the desired htb setup, an 
other script that monitors the bandwidth.  If the bandwidth is not changing 
in 10 seconds, I log the bandwidth to a file and reexecute the htb script 
with other parameters.  
For some test, it takes days before you have enough results.

Stef

-- 

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

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Re: [LARTC] Changing Linux traffic control parameters on the fly

[Stef Coene]

On Friday 28 March 2003 16:12, Simone Leggio wrote:
> Hi all,
>
> I'm executing some experiments in a test network and I have a doubt. It
> is possible to change linux traffic control parameters (say, for
> example, the bandwidth allocated to a flow, its ceiling rate in a HTB
> scheduler, its weight parameter in a CBQ scheduler and so on) while the
> flow is actually traversing a router?
>
> An example: let's assume that a certain class has allocated a bandwidth
> of 500 kbit/sec. Can I change, say after 10 seconds, while the flow is
> still active, the bandwidth allocated to that class to 1 Mbit/sec?
Yes.

> I know there is the command tc qdisc change with which I can change the
> parameters for a qdisc, but how to use it? Launching after 10 seconds
> another tc script?
I do that all the time.  I remove and add the cbq/htb qdisc again while I 
leave the traffic running.  
For allmost all results you can find on www.docum.org, I wrote some scripts.  
Most of the time, I have a script that creates the desired htb setup, an 
other script that monitors the bandwidth.  If the bandwidth is not changing 
in 10 seconds, I log the bandwidth to a file and reexecute the htb script 
with other parameters.  
For some test, it takes days before you have enough results.

Stef

-- 

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


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