Patent ID: 8332516

Claim:
A system for optimized cooperation between resource list servers and presence servers, the system comprising: a physical data storage device on which is stored at least one resource list listing a plurality of presentities; and a resource list server configured to generate a subscription request to a presence server for presence information regarding any presentity listed on said resource list only if no other currently-active subscription request is known by said resource list server to exist for presence information regarding said presentity, wherein said resource list server is further configured to receive a subscription request from a watcher, wherein said received-from-watcher subscription request identifies said resource list and is a request to receive presence information regarding each presentity listed on said resource list, and wherein said resource list server is further configured to provide information regarding said watcher to said presence server; wherein said presence server is configured to maintain a list of resource list server identities, and refrain from maintaining watcher information regarding the subscriber of any of said generated subscription requests where the identity of said subscriber matches any of said resource list server identities.