A network switch includes at least one port processor and at least one switch element. The discharge power of the power storage device at the time when performing engine rotation speed control in a CD mode is greater than the discharge power at the time when performing engine rotation speed control in a CS mode. A heat-generating element is attached to the temperature sensing section, and thus in addition to the opening and closing of the first valve body and second valve body by the thermo-element in accordance with the temperature of the cooling water, the opening and closing of the first and second valve bodies are freely controlled by the application of a current to the heat-generating elementvi. The sending member is made out of resilient material such as rubber. The coprocessor performs the operation designated by the header and returns the altered packet and header to the network processor.