Controller to determine a transmission right and control a timing of communication between nodes

A controller includes a real-time communication unit, an application communication unit, and a socket management unit. The real-time communication unit communicates with an external node by using a first socket on a basis of a transmission right map indicating a node possessing a transmission right out of multiple nodes. The application communication unit communicates, not on a basis of the transmission right map, with the external node by using a second socket differing from the first socket. The socket management unit restricts at least one of transmission of information by the application communication unit to the external node and reception of information by the application communication unit from the external node.