PRESENCE COMMUNICATION SYSTEM

摘要

Provided is a presence communication system for reducing a message number between a presentity and a watcher efficiently thereby to prevent deterioration of a communication quality. A presence server (10a) uses an identifier, which refers to a plurality of pieces of presence information provided by a plurality of presence information suppliers having agreed to a using policy, collectively as a group identifier. The presence server (10a) summarizes and accumulates the presence information for each group identifier, and distributes the presence information demanded to each group identifier. Presentities (20-1) to (20-n) supply the presence information to each group identifier. Watchers (30-1) to (30-n) demand the presence information supplied by the presentities (20-1) to (20-n) for each group identifier, and receive the presence information distributed from the presence server (10a).