A communication apparatus for carrying out communications to and from an external apparatus that includes a first interconnecting unit and a first non-transparent port and effects an interconnection for communications via the first non-transparent port is provided. The communication apparatus includes a second interconnecting unit that includes a second non-transparent port communicably connected to the first non-transparent port. The second interconnecting unit effects an interconnection for communications via the second non-transparent port. The second interconnecting unit performs, when the communication apparatus carries out communications to and from the external apparatus, address translation between an address for use by the communication apparatus and an address for use by the second non-transparent port.