Patent ID: 8670444

Claim:
A network system comprising: a first physical apparatus; a second physical apparatus connected to the first physical apparatus; and a subordinate apparatus being a network apparatus, connected to the first physical apparatus and the second physical apparatus via physical lines, the physical lines constituting an apparatus spanning link aggregation that is a virtual line integrating the physical lines, and, communicating to a virtual machine provided by the first physical apparatus and the second physical apparatus via at least one of the physical lines; wherein each of the first physical apparatus and the second physical apparatus for providing a virtual machine for a network includes: an apparatus-to-apparatus data forwarding section adding identification information of a destination physical apparatus for specifying the physical apparatus of transmitting destination to a virtualization packet, and transmitting the virtualization packet to the subordinate apparatus via any of the physical lines constituting the apparatus spanning link aggregation; and wherein the subordinate apparatus includes: a link aggregation information table storing, with being associated, identification information of a physical apparatus which is the first physical apparatus or the second physical apparatus, and identification information of the physical line which is connected to the physical apparatus and constitutes the apparatus spanning link aggregation; and a forwarding section searching the link aggregation information table, based on the identification information of the destination physical apparatus added to the virtualization packet, for the virtualization packet received from either the first or second physical apparatus, specifying a corresponding physical line in the apparatus spanning link aggregation, and outputting the virtualization packet via specified physical line to either the first or second physical apparatus which is a transmission destination, wherein the forwarding section that, in a case where information indicating whether or not a link aggregation line is to be regarded as individual physical lines and information indicating a physical line to which the packet is output in the link aggregation line are included in a header information of the packet transmitted from the virtual machine regards the link aggregation line as the individual physical lines in accordance with the information and transmits the packet using the physical line in a designated link aggregation line.