Patent ID: 8782160

Claim:
A cluster control system comprising: a plurality of clients; a server group that is connected to each of the plurality of clients through a front network; and a master computer that is connected to the server group through a back-end network and controls the server group, wherein the server group comprises a plurality of slave computers that provide the front network with a single IP (Internet Protocol) address that is a same IP address; each of the plurality of slave computers comprises: a responsible client table that indicate a client for which each of the plurality of slave computers is responsible; and an ARP processing unit that refers to the responsible client table when an ARP (Address Resolution Protocol) request for the single IP address has been received from each of the plurality of clients, sends an ARP response when a client that has sent the ARP request is present in the responsible client table, and does not send an ARP response when a client that has sent the ARP request is not present in the responsible client table; and the master computer comprises a responsible node determination processing unit that maintains and manages through the back-end network in the responsible client table information regarding addition, change, or deletion of a client for which each of the plurality of slave computers is, responsible, wherein each of the plurality of slave computers further comprises: an ARP notification unit that, when receiving an ARP request from a client that is not present in the responsible client table, notifies to the master computer an IP address and a MAC (Media Access Control) address of the client as a new client; each of the plurality of slave computers further comprises a notification flag for determining whether or not to notify the master computer the IP address and the MAC address of the client; and the ARP notification unit determines whether or not to notify the master computer the IP address and the MAC address of the client by checking the notification flag, wherein the notification flag is set at a plurality of slave computers to limit the number of slave computers that notify reception of the ARP requests and prevent a load of the master computer from increasing.