Hi, I have the following scenario:
CUCM ---SIP-----CUBE----SIP----ITSP
CUCM cluster has two servers 10.1.9.5 and 10.1.9.6 (subscriber), we have a CTI application running on 10.1.9.8, we got a bunch of SIP DIDs from ITSP and those SIP DID numbers are mapped to CUCM internal DNs on CUBE through translation, inbound SIP calls to mapped SCCP phones work fine, media stream of internal call leg is established directly between SCCP phone and CUBE as expected. However, when inbound SIP calls to the number which maps to CTI extention, there is no audio, debug on CUBE shows that the media stream of internal call leg is between one of the CUCM server (10.1.9.5) and CUBE. I want to understand why CUCM is telling CUBE to use the IP address which is NOT CTI port is registered from (in this case 10.1.9.8)? why would CUCM treat a CTI extention differently from a regular SCCP phone extension. For regular inbound call to SCCP phones codec between CUCM-CUBE and between CUBE-ITSP are both g11ulaw. I think maybe CUCM thinks that there is a mismatch between CTI end point and CUBE during media negotiation, so it inserts a MTP, but I am not sure, any suggestions where I should start troubleshooting?
Thanks,