Scenario:
PSTN Phone A calls IP Phone B on CUCM cluster via CUBE.
PSTN Phone A-------ITSP-----(sip)------------CUBE----------(sip)----------------CUCM--------IP Phone B
This scenario works just fine, Phone A hears ringback always.
The problem occurs when Phone B answers the call, and then transfers the call to IP Phone C, about 50% of the times I Phone A hear one ringback, or ½ ringback, then silence until Phone C answers.
The other 50% of the time rinback works just fine.
Have you seen this problem before?
I dont have MTP checked on the SIP trunk, codec G711 to all locations. I have tried changing the "Send H225 User Info Message" to all possible options.
I have the ANN in the MRGL for SIP trunk, phones, device pool etc etc.
I did SIP debug on the CUBE on a sucessfull transfer with ringback and without ringback, SIP dialog is identical.
CUCM version 6.1.4.2000-2
Thanks,
Regards
Roger
