[VoiceOps] Easy ways to measure PDD

Peter Beckman beckman at angryox.com
Wed Apr 22 12:08:39 EDT 2015

On Tue, 21 Apr 2015, Alex Balashov wrote:

> Our practice suggests that it's perfectly safe to measure time difference 
> between processing of initial INVITE and either (a) non-100 1xx response 
> (either 183+SDP or 180) or (b) final affirmative answer (2xx).

  Safe to measure? Does that mean it is harmful to measure other things?

  I think it is important to understand the difference between the two
  measurements you mention.

     INVITE to non-100 response: Post Dial Delay
     INVITE to 2xx answer: Ring Time

  Post Dial Delay is something your carrier controls.
  Ring Time is something the called party controls.

  Your carrier should be very consistent in their PDD.

  The called party is often a human which scientific trials have proven
  are random and inconsistent and cannot be relied upon.

Peter Beckman                                                  Internet Guy
beckman at angryox.com                                 http://www.angryox.com/

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