NETWORK RELAY DEVICE AND FAULT MONITORING SYSTEM

摘要

PROBLEM TO BE SOLVED: To prevent influence on a processing of devices other than a destination device of a monitor frame even when a normal frame and the monitor frame are transmitted.SOLUTION: A first system network relay device 2a, when receiving a monitor frame for monitoring faults of a specific destination transmitted from a first system computer device 1a to the specific destination, transmits the monitor frame as it is, while when receiving the normal frame other than the monitor frame from the first system computer device 1a, transmits the normal frame with a communication number added thereto.