PACKET ROUTING APPARATUS AND A METHOD OF ROUTING A PACKET

A routing apparatus includes a plurality of routing units and function units. The routing unit receives a packet from each port, and uses header information contained in the packet to judge whether the packet should be transmitted to the function unit. In the case where the packet should be transmitted to the function unit, the routing unit adds a first identifier to the packet and transmits it to a transmission unit. The function unit receives the packet containing the first identifier from the transmission unit, and executes a predetermined processing for the packet. The function unit adds a second identifier to the packet and transmits it to the transmission unit.