he present invention aims at providing a metal halide lamp having a configuration to achieve the following goals: to prevent the lamp from burning out during the life due to a rise in lamp voltage; and to obtain high luminous efficiency at the same time. The flap valve has a first position in which the protected space is sealed off from a contaminated environment, and a second position in which air from the protected space is allowed to escape into the environment via the opening, wherein the sealing force is a magnetic attraction between a portion of the surface of the valve flap and the valve seat. For example, the manner in which the device processes an access request is dependent on the configuration data. Embodiments then transmit the packet to a first switch module using a first port, the first port specified in the retrieved path information.