Fault-tolerant Ethernet is provided through the use of special interfaces providing end-devices with duplicate ports that may be alternatively enabled with the same network address in the event of a fault detected by loss of the message from a beacon device. Unidirectional network errors in the direction from the end-device to the beacon devices are detected through a path check message from the end-device to the beacon device. Multiple faults may be accommodated without network interruption by adding top-level switches without increasing the number of ports on the end-devices by cross connecting a lowest level of switch.