no alerting tone when calling with softphone

[ilmatte]

Hello dear Cisco friends,

I am experiencing a strange problem and I have no clues on how to troubleshoot it. We have a Cisco environment composed of a UCM and a CCX (on-prem). Under certain circumstances, a user is no longer able to hear the ringing tone. The problem occurs only when using a softphone (CSF) and not while using a normal IP phone like, e.g. a Cisco 7821. The softphone is used in a VDI Enviroment (i.e. Jabber in the remote desktop and JVDI client in the local PC).

The problem is the following: the user with softphone calls another, which has a call forwarding no response to a CTI route point which corresponds to an application in the CCX. Here, after running a script, the call is forwarded back to a Hunt Pilot configured to the UCM. When the user with softphone calls the other user before the call forwarding being executed, he is able to hear the ring tone, but after being forwarded to the hunt pilot, the ring tone is no longer reproduced and the caller hears only silence.

As said, this happens only using a softphone, while using an IP phone, the ring tone is still listenable after the call forward.

What can be the reason for that? Has anyone some idea?

[mradell]

Try and check Media Termination Point Required on the CSF device page in CUCM, save, apply, and re-test.

[ilmatte]

Hi @mradell , sorry for the late reply. This solution (enabling media termination point option) has been already considered but cannot be applied for resource consumption considerations. 

Is there any other possibility or is this the only way to solve this problem? Maybe it could be a routing/firewall problem but honestly I don't have idea on what to check exactly.