Exchange 2013's architecture is very different from Exchange 2010 as we have seen in the last few chapters. In the previous versions of Exchange, all the components for UM were located on a server with the UM server role installed. With the new architecture of Exchange 2013, the UM server role has been eliminated, and the UM functionality now exists across the CAS and Mailbox server roles.

Two new services are used in Exchange 2013 for UM:

The UM Worker Process (UMWorkerProcess.exe) is still present and runs on Mailbox servers. This process, which listens on TCP port 5065 or 5067, is created during the startup of the Unified Messaging service and interacts with incoming and outgoing requests received by the...