Issue forwarding calls CUCM > WEBEX > PSTN

[carl_townshend]

Hi all

we have implemented some trunks from out CUCM to a CUBE then to webex.

we can call the extension from the cucm on webex and it works fine.

we translate the source of the call and prefix it with 8801, so webex sees the 8801 plus the extension as the source of the call.

The issue comes when the user on webex forwards there phone to their mobile or pstn, the call then fails, i can see an error 602 on the cube.

any ideas whats happening here?

cheers

[b.winter]

You could have attached the logs of your failed call already to your OP ...

Provide the logs with the following debugs enabled:
debug ccsip messages
debug voice ccapi ind 1
debug voice ccapi ind 2
debug voice ccapi ind 74

[Maren Mahoney]

Along with the debugs, as @b.winter stated, let us know if the call fails immediately when a call is sent to a forwarded extension or if the call fails after X seconds. A 602 error is a timeout. It is possible that the forwarded station (the cell phone) is neither answering nor is the voicemail picking up before the originating circuit's 'timeout' is reached. 

We run into this in our environment where our service provider will timeout a call after 120 seconds of ringing, so when we design hunting we have to work around that limitation.

Certainly the debugs will be necessary to help diagnose.

Maren

[carl_townshend]

Hi

I have done some more debugs today, it appears if we forward calls to mobile / landline it fails, I have a feeling the ITSP (BT) in our case are rejecting the calls on their SBCs that link our Webex to the PSTN

I am seeing the below on the debugs on my CUBE that sits between the CUCM and WxC

May 6 2024 10:10:43.105: //3812852/E3F682800000/SIP/Msg/ccsipDisplayMsg:
Sent:
SIP/2.0 403 Forbidden

[Roger Kallberg]

Without a complete set of logs we cannot help you with this. Please share the output from the debugs @b.winter mentioned in an attached text file so that we can look at what’s going on.