A. Set up a subzone on Cisco UCM with the peer address to the VCS cluster.

B. Set up a SIP trunk on Cisco UCM with the option Device-Trunk with destination address of the VCS server.

C. Set up a traversal subzone on the VCS server to allow endpoints that are registered on Cisco UCM to communicate.

D. Set up a SIP trunk on the VCS server with the destination address of the Cisco UCM and Transport set to TCP.

E. Set up a neighbor zone on the VCS server with the location of Cisco UCM using the menu option VCS Configuration > Zones > zone.