A switch receives a state change notice from a server via a port, the state change notice indicating that the state is changed. When a port receives a state change notice, the switch shifts the state of the port to a waiting-for-driver-start-up state to prevent execution of a process that corresponds to a signal that is received from the server. When the port receives, after it is shifted to the waiting-for-driver-start-up state, a signal that satisfies a predetermined condition from the server, the switch releases the port from the waiting-for-driver-start-up state.