US Patent 11388076 Relay device and relay method

Monitoring for preventative maintenance using Simple Network Management Protocol (SNMP) polling suitable for a large scale network is realized. A controller of the present invention for use in a system that monitors a plurality of monitored apparatuses by SNMP polling includes a request duplication unit that duplicates an SNMP request from an operator terminal, and a request transmission unit that transmits the duplicated SNMP requests to the monitored apparatuses all at once. The controller includes a response calculation unit that calculates an operator response value from a response value of the monitored apparatus which is retained in an apparatus information database (DB) according to a monitoring policy retained in a monitoring policy DB.