Patent ID: 6891793

Claim:
A network system comprising a high-order node network performing label switching, which includes a plurality of high-order nodes and a plurality of low-order nodes, each of the low-order nodes is connected to one of the plurality of high-order nodes and transfers data to another low-order node through the high-order node network, the network system comprising: first and second high-order nodes, each of which is provided on the high-order node network as one of the plurality of high-order nodes; and a first low-order node is provided on the high-order node network as one of the plurality of low-order nodes, wherein the first low-order node is connected to the first and second high-order nodes via at least one physical line, wherein the first low-order node comprising: a first output port to transmit data to the first high-order node via said at least one physical line; a second output port to transmit data to the second high-order node via said at least one physical line; a selecting section to select one of the first and second output ports in order that the first low-order node transmits data to one of the first and second high-order nodes; a detection section detecting, in the case of the first output port is selected by the selecting section, a communication failure between the first low-order node and the first high-order node; a host change request section making a request to the second high-order node that the second high-order node serves as a high-order node for the first low-order node in place of the first high-order node when the detection section detects the communication failure; and a low-order node setting section performing processes for causing the first low-order node to transmit data to the second high-order node in place of the first high-order node on the basis of process information transmitted from the second high-order node, wherein the selecting section selects the second output port as one of the processes, wherein the second high-order node comprising: a high-order node setting section performing at least one process for causing the second high-order node to transmit data received from the first low-order node to another low-order node corresponding to a destination of the data according to the request of the host change request section; and a process information transmission section transmitting the process information corresponding to the process performed by the high-order node setting section to the first low-order node.