We have a client that is hosting their Exchange server in a datacenter. They want a CUCM cluster installed on-site. I read that the Unity server must sit on the Exchange server LAN in the datacenter. The main site is connected to the datacenter with a site-to-site VPN.
I found one doc that stated a Unity server could reside at both the datacenter and the main site, but no mention on how they interact with one another.
What is the proper way to integate the CUCM cluster with the Unity server offsite?