Adaptive routing in a contextcast overlay network

Context-based communication allows for the dissemination of messages to mobile users with a specified context, i.e. at a location and with certain attribute values. This enables, e.g., a message to students on campus attending a certain class, with information about a study group for an upcoming exam. An overlay network of context-aware routers efficiently disseminate the messages to all matching receivers. Directed forwarding of such messages requires that the routers maintain knowledge about the contexts of connected users. Global knowledge, i.e., each router knowing about every user, scales poorly, though, because of the necessary updates.