ICT Trunk between two CUCM Clusters running on different major version

[aniket0422]

Hi Team,

Can we have ICT trunk (Non Gatekeeper Controlled) between two CUCM Clusters running on different major version.

We have CUCM-9.1 running having ICT trunks with other CUCM Cluster. And we are planning to upgrade this CUCM from 9.1 to 11.5. Will our ICT trunk keep working after upgrade ?

Regards,

Aniket

[Jaime Valencia · Accepted solution]

Yes, however the recommendation is to use SIP trunks for CUCM 8.6+ and only use ICT if you're using releases prior to 8.6

[EthanSmith1]

OK we have 10.5 PCCE and a 10.5 back office CM clusters w/Unity Connection connected with ICT. Calls begin in PCCE with a basic script that asks you to enter your parties extension. The end-users are on the 10.5 back-office. Calls route fine to the extension when entered. But when the call goes to voicemail it drops the call. I can call directly from the PCCE to back office and it goes just fine to voicemail. It's only when you use a script that it fails

Interesting item is that the phone is un-plugged on back office the call routes just fine to voicemail from the script

Any ideas?