Patent ID: 7379458

Claim:
A server load sharing system comprising: (A) a plurality of server load balancers each accommodating at least first and second links, said balancer including: (a) a module selecting, when receiving a forwarding target packet addressed to a predetermined virtual IP address via one of said first and second links, any one of a plurality of load sharing target servers specified in their group on the basis of this virtual IP address and each allocated a unique IP address; and (b) a module rewriting the virtual IP address of the received forwarding target packet addressed to the virtual IP address into the unique IP address of said selected load sharing target server, and rewriting a source IP address of the received forwarding target packet addressed to the virtual IP address into an IP address capable of specifying the other of said first and second links; and (B) a relay device connected to each of said plurality of server load balancers via said first and second links, further connected to each of said plurality of load sharing target servers via other links without directly connecting said plurality of server load balancers to said plurality of load sharing target servers, and separated from said plurality of server load balancers, said relay device including: (c) a module identifying the received forwarding target packet addressed to the virtual IP address; (d) a module selecting one of said first and second links for forwarding the identified forwarding target packet addressed to the virtual IP address to one of said plurality of server load balancers; and (e) a module forwarding the forwarding target packet, the forwarding target packet received via the other of said first and second links from a specific server load balancer that received the forwarding target packet addressed to the virtual IP address via one of said first and second links within said plurality of server load balancers to said selected load sharing target server, and forwarding the forwarding target packet sent back from said selected load sharing target server to said specific server load balancer via the other of said first and second links.