[asterisk-users] How to create distortion, echo, and chopping sound in a SIP trunk?

[Matt Riddell]

On 29/04/11 3:25 AM, Bruce B wrote:
> Hi everyone,
>
> How can I introduce some distortion, echo, chopping sound and all other
> bad quality things that can happen to a SIP trunk? I have plenty of
> bandwidth and crisp clear lines so the only thing that I can think of is
> to limit bandwidth but even that requires quite some scripting work.
>
> Is there any easy way to simulate a distorted SIP line temporarily for
> testing?
>
> I am appreciate experienced inputs.

The text from that link:

Packet loss

Random packet loss is specified in the 'tc' command in percent. The 
smallest possible non-zero value is:

232 = 0.0000000232%

  # tc qdisc change dev eth0 root netem loss 0.1%

This causes 1/10th of a percent (i.e 1 out of 1000) packets to be 
randomly dropped.

An optional correlation may also be added. This causes the random number 
generator to be less random and can be used to emulate packet burst losses.

  # tc qdisc change dev eth0 root netem loss 0.3% 25%

This will cause 0.3% of packets to be lost, and each successive 
probability depends by a quarter on the last one.

Probn = .25 * Probn-1 + .75 * Random

-- 
Cheers,

Matt Riddell
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