102 Recovery on Timer Expiry - CUCM 14SU3 - SBC - VISP

[RAustin70]

In May I moved from TDM thru 4431's to SIP thru 8300's.  I have been trimming down dropped call issues, and up next is 102 codes.

This is sparse, but I am a fan of 99.999% reliability of Telecom.  For example, from 1 July to yesterday we had 23,106 calls traverse our SBCs.  Of those, 71 calls threw a 102 code on OrigCause, and 2 threw a 102 code on DestCause.

The duration on the calls range from 2 seconds all the way up to ~903 seconds.

I did some JFGI Engineering and most posts about 102 Cause related to ISDN and TDM Circuits.  One listed to have:

!
ip rtcp report interval 3000
!
gateway
 media-inactivity-criteria all
 timer receive-rtcp 5
 timer receive-rte 1200
!

My SBCs have

gateway
media-inactivity-criteria all
timer receive-rtcp 40
timer receive-rtp 86400

Am I on the right track with this, or should I be looking in a different direction?  I just noticed, that every '102' coded inbound call that the duration is 903+ seconds is from the same number to different numbers

[sidshas03]

You've identified 71 calls with 102 response codes out of 23,106, suggesting some issues but not widespread. Notably, long-duration inbound calls with 102 codes come from the same number, so check that caller's setup. Adjust your gateway settings, especially timers and media inactivity criteria, to see if it helps. Keep analyzing call patterns, monitor network conditions, and review SBC logs for more insights. Focus on commonalities among problematic calls to improve reliability.

[RAustin70]

Thank you for such a prompt Response!!  One point on this, 

of those 71 Inbound calls that failed, 17 of them were from the same calling party number from offsite.  That number made a total of 117 calls into our system this month, and so long as call duration was under 826 seconds, the O/D Cause Codes were 0/16 respectively.  as soon as it hits 903 seconds or more, it flips O/D Cause to 102/0.

[sidshas03]

You're welcome! It looks like the issue is specific to calls from that number when they go over 903 seconds. Try adjusting your `timer receive-rtp` to around 1200 seconds and see if that helps. Also, check the logs for any patterns and reach out to the carrier if needed. Let me know how it goes!

Thank you.

[RAustin70]

I have been playing with this for a week, changing the timer settings, changing the report interval, all to no effect.  I am thinking this may be a setting above my SBC somewhere.  The part that blows my mind is we get calls over 903 seconds every day with out issue, and of these 102 coded calls, 98% of them are from one particular number that belongs to a MS Teams audio conference system.  When my customers join a Teams meeting from their computer, and they select 'call me' this number dials their desk phone through my system.  and none of those make it past 903 seconds.