PINGING FOR THE PRESENCE OF A SERVER IN A PEER TO PEER MONITORING SYSTEM

摘要

A system that comprises a dynamically changing set of client and server devices (10). Client devices send detection messages (64a, 66a, 68a) to a server device (10), for detecting active presence of the server device (10) in the system. The server device (10) selects assigned time points for transmission of subsequent detection messages from respective ones of the client devices (10). The server device sends timing information that represents the selected time points (10) to the client devices (10) in response to the detection messages (64a, 66a, 68a).The client devices send renewed detection messages (64ó,c, 66b, 68b), using the timing information to time sending of the renewed detection messages (64ó,c, 66b, 68b) substantially at the assigned time points.