This is actually addressed in the Cisco Unity design guide as connectivity between Unity and Exchange is critical for reliable performance.
Physical Placement and Network Infrastructure
To ensure that Cisco Unity functions properly, we require that a Cisco Unity server be in the same data center as the following servers:
•
The Exchange server that Cisco Unity communicates with, commonly known as the partner Exchange server. For more information on the partner Exchange server, see the "Exchange Considerations (All Versions)" section.
•Every Exchange server on which mailboxes for that Cisco Unity server are homed. If Cisco Unity is separated by a WAN from an Exchange server on which subscriber mailboxes are homed, a second Cisco Unity server must be co-located with the remote Exchange server.
•At least one domain controller. If Cisco Unity subscribers are homed in more than one domain, a DC for each domain must be in the same data center as the Cisco Unity server.
•At least one global catalog server.
•At least one DNS server.
These requirements apply regardless of whether the non-Cisco Unity servers are customer provided, or are Cisco provided and dedicated to Cisco Unity.
Connect the Cisco Unity server and the servers that Cisco Unity relies on with a high-speed switched gigabit network with no congestion. Total MAPI response time must be less that 10 milliseconds.
The Cisco Unity server should be installed into the same Windows site as the Exchange servers it services.
For full details, take a look at the full design guide here (http://www.cisco.com/en/US/docs/voice_ip_comm/unity/5x/design/guide/5xcudg040.html).
Note that the documentation for version 5.x still applies for version 7.x (i.e., new documentation was not developed for 7.x and Cisco simply refers users on that version to the 5.x documents). This is also for connectivity to Exchange in general - the specific version is not a factor as the integration mechanisms are the same (MAPI, etc).
Hailey
Please rate helpful posts!
