Calls from SCCP phone to CTI_port randomly canceled

[dgonzalez1]

Hello, I'm investigating and issue where several times a day the customer experiences random call drops. I see in the traces that when the phone sends an INVITE to the CTI_port, after receiving the 180-Ringing, it send a CANCEL. I got the SDL traces from RTMT (and some others) but I cannot figure it out which the problem could be.

Could please anyone give a look?

I'm attaching the messages and the SDL trace from the 180-Ringing to the CANCEL.

Thank you in advance.

[b.winter]

What is the CTI-port used for?
If you just add a CTI-port in CUCM, then its associated number is not call-able, because there is not "real" device, which is able ring.

If you have a contact center application or any other application controlling the CTI-port, then check if the port is registered in CUCM and the port can be controlled by that application.

[Carlo Poggiarelli]

Hi,

In your trace I found that the CUCM is invoking an MoH resources using codec G723 while passing the call to the aget with extension 9844. Cumc is trying to invoke an MTP resource but it fails due to an usupported codec.

Can you please specify the call path? Eg. if the calling user is an external one and which service is using the CTI resources.

Also please check the Region settings for Agent's phone and CTI Port.

Please let us know

BR

Carlo