Post dial delay how is it calculated?

[fusionpbxnoaudio]

I am trying to understand what constitutes the value that appears in the PDD column in the CDR

When I dial a local extension, the PDD on fusion PBX is 1.5s to 2.5s - however when I call a PSTN line, it is just 0.82 - I don't understand how that is possible (some times it is 0.38).

I did a sngrep on the time taken for the invite and other things appear to be similar in both cases though.



The above is a call to local extension, the following is a call to PSTN

 

[DigitalDaz]

The PDD should be the figure between the initial INVITE and either the 180 Ringing or 183 Session Progress.

In the first case it was about 0.75 seconds in the second case it was much the same.