Context-aware unified communication

Enabling people-to-people interaction across heterogeneous communication end-points enhances user experience and fosters people collaboration. This paper presents the design and implementation of a unified communication system, dubbed Mercury, that allows a user to interact with others using the most convenient device at the time. Mercury supports both two-way conversation and one-way messaging. It leverages the Session Initiation Protocol to manage communication sessions and exploits dynamic user context to proactively route and migrate calls. It allows for subscription to other users´ unified reachability status and provides a soft ring feature via universal notification. Mercury has an extensible architecture that allows new device types to be easily incorporated into the system. Our prototype implementation integrates a variety of devices: telephones, Sametime instant messaging clients, email, and pagers.