Patent ID: 7161900

Claim:
A redundant Ethernet transmission line system comprising: Ethernet transmission lines having an active transmission line and a standby transmission line as a redundant configuration; first transmission equipment having an Ethernet switch; and second transmission equipment connected to the first transmission equipment through the redundant Ethernet transmission lines, wherein the Ethernet switch, has a function of storing a source MAC address contained in a received frame signal and a port from which the frame signal is received in the form of a pair in a learning table, and reading a destination address of a frame signal and transferring the frame signal according to the source MAC address and the port stored in the learning table, and the Ethernet switch notifies a failure on the active transmission line to the second transmission equipment by stopping a link pulse to the second transmission equipment when the failure is detected, and wherein the second transmission equipment has a function of sending out a frame signal only through the active transmission line, and the second transmission equipment detects the failure on the active transmission line due to the stop of the link pulse from the first transmission equipment, and then the second transmission equipment sends out the frame signal through the standby transmission line so as to switch over from the failed active transmission line to the standby transmission line.