The principle reason to distribute implementation of your Messaging system is local survivability. You can distribute the entire network and place application servers at all locations or only those segments where you do not want the Messaging service to be interrupted. By placing application servers at remote sites, you can ensure continuation of messaging service in the event of a network outage between the remote site and the main location. If the storage server at the main site becomes unreachable to the local server, users at the remote site experience no difference in service and can retain user messages of the previous 72 hours. Another benefit of the distributed multisite configuration is that WAN has less voice traffic. However, you might not be able to maximize the server capacity.
