Call Drops - 487 Request Terminated error.

[Shadragon]

Hoping someone can shed light on this.

We've had a series of dropped calls. They appear to be random throughout the day, across several extensions, both queue and direct DID calls. I can't find any commonality between them.

Of the three calls I've found in the logs (the users are remarkably lax in reporting specifics), two calls lasted 0:37 seconds and the third 0:54 seconds.

Entries in the activity log are found for each call, in this format. (In two hours, I had 22 of these)

12/12/2018 10:33:26 AM - [CM503003]: Call(C:5628): Call to <sip:[email protected]:5060> has failed; Cause: 487 Request Terminated/INVITE from 192.168.1.43:5062

No recent changes to the system, it is v15.5.15502.6, fully updated. All Yealink phones use standard firmware and are up to date as well. System connects to the telco via a PATTON 4960 E1.

 

[eddv123]

A "487 request terminated" can be what a UAS will send to the client after the client sends a CANCEL request for the original unanswered INVITE request.

Translated this could easily be when a call has taken place but the destination user has "Cancelled" the call before a session has been established, so could be a red herring.

Either way it would be quite difficult to capture this issue as it is intermittent. If you do attempt this use the below examples:

3CX: https://www.3cx.com/docs/collecting-logs-for-3cx-support/
Patton (if calls relate to external): https://www.3cx.com/docs/patton-isdn-debugging/

Capturing this issue with the Patton would be fantastic as it is very detailed and could give you a definitive answer.

Out of the calls dropped can you confirm whether you may of hit a call limit perhaps either on the PRI lines (reaching channel limit), if it were on 3CX however you would get a message regarding licence limit reached.

The Patton 4960 is a pretty old unit and has been replaced with the 4970's in the smartnode range, this should not pose any issues, however I would ensure that you are running the latest 6.11 firmware which can be found here: https://www.patton.com/support/upgrades/index.asp?um=SmartNode 4960

I would doubt this would be down to the Patton if auto-configured by 3CX, so please try and pin-point exactly what types of calls (internal/external/international etc) the issue relates to and acquire a trace if possible.