The topology for Communicator Mobile works exactly as Office Communicator as soon as it has network connectivity over a wireless data network. Communicator Mobile clients connect to the topology based on the network that the device is connecting to. An external user, connecting by a cellular data connection, communicates with an Office Communications Server Edge Server to gain access to other clients. Internal users, connecting by a Corporate WI-FI connection, communicate directly with their home server. Communicator Mobile and Office Communicator exercise many of the same key processes for client connectivity, authentication and discovery.
The following figure displays Communicator Mobile scenarios in an Office Communications Server 2007 R2 deployment.