[VoiceOps] Easy ways to measure PDD

Calvin E. calvine at gmail.com
Mon Apr 20 20:43:56 EDT 2015

Asterisk does have logging and can write CDR with start time and answer
time. The exact details will depend on the version of Asterisk you are

For example,

Watch for lines with "disposition" = "ANSWERED" and calculate the
difference of "start" and "answer".

Your requirements dictate that you know the PDD immediately, not as each
call ends. You might have to do some digging to get that from the logs
directly, or force CDRs to be written when calls are answered as well as
when they end.

A "no ring timeout" setting will help to help route advance when facing
unexpected PDD. 4 seconds is reasonable for most carriers, in my experience.

This problem might already be solved by the asterisk community. Have you
checked those forums/mailing lists?

Now might be the time to consider the future of your routing, rating,
billing, monitoring, and alerting. The right solution now might save you
considerable time and effort later.

If you really want to do this yourself, consider attaching your Asterisk
boxes to a RADIUS server and doing your CDR crunching from there.


On Mon, Apr 20, 2015 at 1:02 PM, Peter Beckman <beckman at angryox.com> wrote:

> On Mon, 20 Apr 2015, Richard Jobson wrote:
>  Do you have an SBC or switch that already measures this and outputs it
>> with
>> the CDR?
>  Nope.
>  Do you want to report on all PDD long-term?  Or just one or two specific
>> calls?
>  Long term. A handful of Asterisk servers. Looking for what Calvin E.
>  suggested, except a tool that someone has already written. I can do what
>  Calvin suggests, but interpreted scripts are no match for C compiled
>  packet matching.
>  What Calvin suggests is something that would work for a PCAP file
>  processed after the fact. I'm looking for something that would be able to
>  catch the non-100 response for each INVITE and log it to a file or send a
>  metric. Even if it has to wake up and parse a 80MB+ pcap file each run to
>  find the PDD per Call-ID, then determine if that Call-ID has been
>  reported. Lots of caching of data... it can be done, but speed is
>  important and a scripting language is quick and dirty but unlikely to be
>  fast and reliable.
>  Does Asterisk support logging or emitting metrics like PDD?
>  When a carrier jumps from <1 second Post Dial Delay to 20+ seconds Post
>  Dial Delay I need (a) to know about it and (b) be able to demote them in
>  my LCR in an automated fashion temporarily so I don't need to wake up and
>  take care of my customers.
> Beckman
> ---------------------------------------------------------------------------
> Peter Beckman                                                  Internet Guy
> beckman at angryox.com
> http://www.angryox.com/
> ---------------------------------------------------------------------------
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://puck.nether.net/pipermail/voiceops/attachments/20150420/10051953/attachment.html>

More information about the VoiceOps mailing list