RING NODE DEVICE, AND RING NODE REDUNDANCY METHOD

PROBLEM TO BE SOLVED: To provide a ring node device and a ring node redundancy method capable of smoothly changing from a main system to a standby system in an event of failure where it is able to maintain compatibility with a conventional system because of allowing to separate as a maintenance unit, while keeping a redundancy configuration capable of securing a transmission line even when the event of failure. SOLUTION: The ring node device 100 including an RPR card Y(w) 110 of the main system and an RPR card Y(p) 150 of the standby system, upon detecting disconnection of a communication link between the RPR card Y(w) 110 and an L2/L3 switch 200, changes from the RPR card Y(w) 110 of the main system to the RPR card Y(p) 150 of the standby system, and controls communicating with the L2/L3 switch 200, so that it is able to smoothly change without disconnecting the communications between the ring node device 100 and L2/L3 switch 200. COPYRIGHT: (C)2007,JPO&INPIT