Jitter and intrapacket delay
Urtho
junk at urtho.net
Tue Jul 17 15:38:22 EDT 2007
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.
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