Patent attributes
A relay device includes: a memory; and a hardware processor coupled to the memory. The hardware processor: receives data from a sensor; backs up the data from the sensor, in the memory, to store data failed to be transmitted to a server on a network; determines, based on a server communication status representing a state of data transmission to the server, a priority for data to be transmitted to the server among the data from the sensor and the backed-up data; transmits, to the server, data determined to have a highest priority among the data from the sensor and the backed-up data; and determines the server communication status based on whether communication with the server fails.