Control system and control method
A route failure and a device failure are detected in a short time without erroneous recognition. A multiplexing system includes: a first system having a pair of processing devices forming a pair; a second system having a pair of processing devices forming a pair that are different from the first system; each processing device of the first system and the second system includes a survival monitoring unit configured to monitor a failure of the each processing device or the each LAN based on a device time-out for confirming survival of the each processing device and a route time-out for confirming survival of the each LAN set to be longer than the device time-out.