This section describes the presence components and the relationship between these components. It also shows the process boundaries for the various components.
The primary presence components of Office Communications Server 2007 R2 are the User Services module that runs inside the RTCSrv.exe process and the RTC Aggregate application that runs inside the RTCHost.exe process. The User Services module processes registration requests received by a Front End Server and sends presence, registration, and conferencing data to the Back-End Database Server to keep the presence store in the SQL database synchronized with user and contact objects in Active Directory. The RTC Aggregate application aggregates presence information from multiple client endpoints into one presence document.
The following figure shows the presence components.