Currently I'm running a acceptance test on a SIP Trunk from our ISP. Everything is working fine except the DTMF.
[GenBand SBC] ---- [SIP Trunk into CUCM 7.1] ---- [Cisco Unity Express 7.0]
The SIP Trunk as well as the CUE are in the same region supporting only G.711. On the SIP Trunk I've tried all different kind of DTMF configurations (No Preference, RFC 2833 and OOB). We've tried to force the GenBand SBC to only use RFC 2833 as well as the SIP Trunk. But this didn't work, not even after we added a MRGL with MTP's.
Is there some sort of best practive to implement DTMF over a SIP Trunk? Is there a way I can do some debugging on the CUCM/CUE?
Paul van den IJssel
Can you try to check "Accept Unsolicited Notification" of the SIP Trunk Profile which your SIP trunk is using?
Go to System -> Security profile -> SIP Trunk Security Profile -> find the profile name in use (Default: Non Secure SIP Trunk Profile).
Now CUCM should not respond with 403 Forbidden.
Hope that helps.