Patent ID: 8774058

Claim:
A network system, the network system comprising: a plurality of extension units, each containing a dualized basic unit and a dualized extension Ethernet module; a first ring network connected by a first basic unit and a plurality of first extension Ethernet modules; and a second ring network connected by a second basic unit and a plurality of second extension Ethernet modules, wherein each of the plurality of first extension Ethernet modules transmits or receives data along a network path determined by judging, by the first extension Ethernet module, if the first ring network is connected to the plurality of second extension Ethernet modules using an intrinsic number of each extension Ethernet module, wherein the plurality of first extension Ethernet modules and the plurality of second extension Ethernet modules determine whether to operate as a master mode or a slave mode using a hop count in a single ring network and using status information from the first basic unit and the second basic unit, respectively, in a dual (dualized) ring network.