ATM switch capable of routing IP packet

An ATM switch comprising:

• an ATM switch unit;
• a switch control unit for controlling said ATM switch unit;
• one or more circuit accommodation units for receiving IP packets which have been segmented into ATM cells from one or more external ATM networks, respectively, and for transferring said ATM cells to said switch unit;
• and
• an IP routing process unit for routing IP packets as segmented into their component ATM cells, without requiring reassembly of the segmented IP packets from their respective component ATM cells;
• wherein said IP routing process unit comprises:
• a cell storage unit having a plurality of memories, each of said plurality of memories having a capacity for storing a plurality of ATM cells;
• a distributing means for distributing said ATM cells received from said ATM switch unit to said plurality of memories while grouping said ATM cells in each of said plurality of memories in accordance with an IP packet to which each of said ATM cells belongs;
• a sending means for sending all the ATM cells belonging to an identical IP packet when said all the ATM cells belonging to said identical IP packet have been stored in a respective one of said plurality of memories;
• and
• a means for converting a VPI/VCI (Virtual Path Identifier/Virtual Channel Identifier) of each of said all the ATM cells belonging to said identical IP packet.