Patent ID: 7983190

Claim:
A network system comprising: a plurality of layer 2 communication devices that constitute a plurality of layer 2 networks that have loop configurations with blocks positioned differently; and a layer 3 communication device that performs communication through the plurality of layer 2 networks without communicating through the blocks, wherein each of the layer 2 communication devices includes an identifying unit to identify an Open Shortest Path First (OSPF) packet or a Routing Information Protocol (RIP) packet from among packets passing through the layer 2 communication device; and an embedding unit to embed routing control information for a layer 2 network in the OSPF packet or the RIP packet, and the layer 3 communication device includes a selecting unit to select, from the plurality of layer 2 networks that have the loop configurations with the blocks positioned differently, an optimum layer 2 network based on the routing control information for the layer 2 network embedded in the OSPF packet or the RIP packet; and a setting unit to set a packet to be transmitted to the optimum layer 2 network.