SERVER DEVICE, CLIENT DEVICE, AND COMMUNICATION SYSTEM

PROBLEM TO BE SOLVED: To ensure the reliability of memory contents, without having to provide redundant installation in a communication system comprising a server and clients. SOLUTION: In the server 100, a path route information management table 300 for storing path route information on a communication path 200 set between a plurality of clients is stored in a memory 104. The path route information is collected from all the connected clients by the path route information collecting block 102, and the contents of the management table are reconfigured based on the collected information, in at least, any one of the cases where a path route information managing block 101 detects that the management table has been erased, where a communication path is newly set by receiving a request for belonging from a client 240 not yet belonging to any server, where a request for the reconfiguration of the management table is received from any of the belonging clients 210 to 230, and where a predetermined period of time has passed since the last execution of reconfiguration operation.