Patent ID: 8352771

Claim:
A network system comprising: a path control unit that sets a main path and a spare path; and a plurality of data transfer units that transfer data according to instructions from the path control unit; wherein the main path and the spare path provide paths between a first one of the data transfer units and a second one of the data transfer units, wherein each of the data transfer units includes an interface for transferring data, and a power control unit for reducing power consumption in the interface in a non-operating state, wherein the path control unit sets the spare path based on the connection status of at least one of the data transfer units and the power consumption reduction capacity of the at least one of the data transfer units, wherein one of the power control units sets a respective interface on the spare path to a power-saving state when the spare path is set in the non-operating state, and wherein the one of the power control units changes the respective interface on the spare path from the power-saving state to a normal state when the spare path is set in an operating state.