[LARTC] jitter generation

[LARTC] jitter generation

[ciprian niculescu]

Hi,

in a project i must degrade the voip/video, i know to do latency (tbf), 
but i don't know how to create jitter. I want to do it on a 
router/bridge and not the generating equipment. Any have a idea, or know 
a piece of code that do it?

Thanks

Ciprian
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Re: [LARTC] jitter generation

[Oscar Mechanic]

Using nth or random from iptables set a mark then set the tc filter for
different BW's based on different marks. 

You could drop the packets but that is not really jitter more
compensation testing.

Also play around with burst in HTB but you will need more than one call
for this to be useful.
 
On Fri, 2005-10-21 at 11:57 +0200, ciprian niculescu wrote:
> Hi,
> 
> in a project i must degrade the voip/video, i know to do latency (tbf), 
> but i don't know how to create jitter. I want to do it on a 
> router/bridge and not the generating equipment. Any have a idea, or know 
> a piece of code that do it?
> 
> Thanks
> 
> Ciprian
> _______________________________________________
> LARTC mailing list
> LARTC@mailman.ds9a.nl
> http://mailman.ds9a.nl/cgi-bin/mailman/listinfo/lartc

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Re: [LARTC] jitter generation

[Andy Furniss]

ciprian niculescu wrote:
> Hi,
> 
> in a project i must degrade the voip/video, i know to do latency (tbf), 
> but i don't know how to create jitter. I want to do it on a 
> router/bridge and not the generating equipment. Any have a idea, or know 
> a piece of code that do it?
>

Use netem -

http://linux-net.osdl.org/index.php/Netem

Andy.
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Re: [LARTC] jitter generation

[BUCHMULLER Norbert]

On Fri, 21 Oct 2005 11:57:22 +0200
ciprian niculescu <cnicules@4email.net> wrote:

> in a project i must degrade the voip/video, i know to do latency (tbf), 
> but i don't know how to create jitter. I want to do it on a 
> router/bridge and not the generating equipment. Any have a idea, or know
> a piece of code that do it?

Hello,

I've never tried, but the "Network emulator" (CONFIG_NET_SCH_NETEM) from
the kernel QoS code does the very same thing (according its configure
help section).

Let us know if (and how:-) it works, please. (I'm very interested.)

norbi

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Re: [LARTC] jitter generation

[Scott Lamb]

On 22 Oct 2005, at 08:35, BUCHMULLER Norbert wrote:
> I've never tried, but the "Network emulator" (CONFIG_NET_SCH_NETEM)  
> from
> the kernel QoS code does the very same thing (according its configure
> help section).
>
> Let us know if (and how:-) it works, please. (I'm very interested.)

I just tried it the other day. It's surprisingly easy to use and you  
can simulate a lot of conditions.

Documentation is lacking, but this wiki page helps a lot:

http://linux-net.osdl.org/index.php/Netem

You may need a pretty modern kernel. I hit a crash bug in one of  
RedHat's customized 2.6.9 kernels. The people on the netdev list  
mentioned a chance since then that may have fixed it. Haven't tried  
it yet, but the same operation worked fine for them.

-- 
Scott Lamb <http://www.slamb.org/>

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