Office Communications Server 2007 R2 provides multiple server roles with specific purposes for building your enterprise instant messaging and conferencing infrastructure.

The Enterprise Edition scales the capacity of the Standard Edition Server to a larger magnitude by splitting the different logical functionality into separate physical servers. The Director redirects user connections to the user’s home server or home pool. The Conferencing Servers, or MCUs, manage the content for Office Communications Server 2007 R2 conferences. The Application Server provides a platform for Conferencing Attendant, Conference Announcement Service, Response Group Service, and Outside Voice Control applications. The Edge Servers are deployed in the network perimeter to enable connectivity outside the organization’s private network. The Archiving Server performs server-side recording of call details and archiving of all IM communications. The Monitoring Server performs CDR and QoE data gathering. Communicator Web Access provides a Communicator client experience from a Web browser for users without Office Communicator installed on their computers.