To transfer data at a high speed by using multiplexed logic connection and to reduce the internal storage area.

A user terminal equipment outputs a data transfer request designating a user terminal equipment of a transfer destination to an interface processing section 11. When the interface processing section 11 informs a user terminal equipment of a transfer destination, a virtual channel identifier(VCI) management section 13 outputs a head address of a storage area storing connection information not assigned at present from an internal VC management table to the interface processing section 11. Upon the receipt of a notice of the head address by the interface wavelength 11, a protocol processing section 14 informs the head address to a connection information storage section 12. The connection information storage section 12 outputs a protocol parameter including connection information having the noticed head address, a virtual path identifier(VPI) and a VCI to the protocol processing section 14. The protocol processing section 14 executes protocol processing based on the received protocol parameter.