Patent ID: 8693343

Claim:
A relay apparatus comprising: a processor; and a memory, the processor being coupled to the memory and configured to: store destination information about a destination of a multicast packet in association with a multicast address; determine whether the destination of the multicast packet is a first physical machine on the basis of the destination information stored in a migration process in which a virtual machine operating on the first physical machine is migrated to a second physical machine; and add information about the second physical machine to the destination information the destination information corresponding to the multicast address that indicates the destination of the first physical machine, if the determination determines that the destination of the multicast packet is the first physical machine, wherein the relay apparatus is notified of the information about the first physical machine, the information about the second physical machine, and a virtual network number for identifying a virtual network to which the virtual machine belongs if the determination determines that the migration process is to be executed, wherein the multicast address and the destination information is stored in association with the virtual network number of the virtual network to which the first physical machine, which is the destination of the multicast packet, belongs, wherein the determination determines whether the multicast address corresponding to a combination of the first physical machine and the virtual network number is stored, and wherein the information about the second physical machine is added to the destination information, corresponding to a multicast address, if the determination determines that the multicast address corresponding to the combination of the first physical machine and the virtual network number is stored.