[SIPForum-discussion] Post Dialing Delay (PDD)

[Hadriel Kaplan]

________________________________
From: discussion-bounces at sipforum.org [mailto:discussion-bounces at sipforum.org] On Behalf Of Halit Sakca
Sent: Friday, April 18, 2008 11:43 AM

> Can Anyone help me how we can measure and verify that the PDD is under
> a certain value?
>
> Is there any ITU-T value for the PDD to take as a reference?
>
> Our NGN provides the IP connetivity to IP carriers through Acmepacket SBCs.

For doing that mentioned above you will need a mirror port on switch anyway.
If you can not set the time of all components same via NTP and trace separately.

No, you don't need to do that with mirroring - most SBC's measure that time already and report it, as do other SIP device types.  PDD can typically be fully measured at one spot, although it may not represent the user's perceived PDD if it's not measured at the originating provider.
Also, you don't really need NTP, because the number is a differential value measured by the same entity that sends the INVITE request.  Thus the local view of global time does not really matter. (it does matter for reporting/determining when calls are made, but not for their delays or durations)

-hadriel
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