Jitter and intrapacket delay

[Urtho]

On 2007-07-17, at 21:23, Carter Bullard wrote:

> Hey Urtho,
> remember std deviation is the square root of the variance, so
>        variance = stddev ^ 2.0.

:)
  Your words put into an equation:
      stddev = variance ^2.0

and thus variance = stddev^0.5

>
> well, 50 pps is a packet interval of 20mSec which is pretty normal for
> some VoIP implementations.  do you think 50 is too high, or too low?
>
50pps is what I set in my devices but I meant that some flow have  
higher rate than 50pps and I should check how is that possible.
eg with "statistical" analysis of the same data in Ethereal.

> also remember that argus is good at dealing with silence suppression
> for some rtp based codecs, so the jitter may reflect a higher packet
> rate than what is actually seen for the general flow when silence
> suppression is in use.
>
Yes, I've just diagnosed that some of my installations have VAD  
turned on by mistake thanks to Argus :))

Urtho.