Router apparatus using ATM switch

A packet switching device which switches packets comprising:

• managing means which manages route information of said packets;
• a control unit which controls said packet switching device as a whole;
• a plurality of input line interfaces,
• wherein each line interface comprises:
• receiving means which receives variable-length packets from an input line,
• storage means which stores therein said route information from said control unit,
• determining means which determines routes of said variable-length packets received based on contents of said variable-length packets and said route information stored in said storing means, and
• means for converting said variable-length packets into a plurality of fixed-length packets respectively, and outputting each of said fixed-length packets by adding thereto said route information determined by said determining means;
• a multiplexing unit which receives said plurality of the fixed-length packets outputted from said plurality of line interfaces, and multiplexes said fixed-length packets to output a plurality of fixed-amount packets each having different route information;
• a switch which receives said plurality of fixed-length packets each having different route information outputted from said multiplexing unit and outputting each of the fixed-length packets in accordance with said route information attached thereto;
• and
• an output line interface which receives said plurality of the fixed-length packets outputted from said switch and assemble the original variable length packets therefrom to output them to an output line.