The XDB Server makes use of a client-server architecture, which allows an application to be split into front-end (client) and back-end (server) components. The front-end components correspond to the end user's view of the application. The back-end is the XDB Server, which performs the actual database processing functions.
The front-end and back-end can reside on the same machine or they can be installed on a back-end server machine, with front-end client sessions initiated from separate workstations.