Patent ID: 7630373

Claim:
A packet transfer apparatus, comprising: a plurality of line cards; a control card; and a switch fabric, wherein: each of the plurality of line cards comprises: at least one input line for inputting a packet from a network outside the apparatus; at least one output line for outputting the packet to the network outside the apparatus; an internal line for communicating the packet with the network in the apparatus; a first routing table for recording a plurality of transfer information items each corresponding to a destination address; a second routing table for recording the plurality of transfer information items each corresponding to the destination address; a route search engine for searching the first or second routing table, by using as a search key the destination address included in a packet received from the input line, for a transfer information item corresponding to the destination address; a packet processor for issuing a search request to the route search engine, receiving the transfer information item as a result of the search, conducting a process required for the packet, and transferring the packet to the internal or output line; and a first control Central Processing Unit (CPU); the control card comprises: a third routing table for recording the plurality of transfer information items each corresponding to the destination address; and a second control CPU having a function to control the third routing table; the switch fabric transfers in the apparatus a packet to the packet processor associated with the output line designated for the packet; the third routing table records all transfer information items in the packet transfer apparatus; the second routing table records a part of the transfer information items of the third routing table, and the part of the transfer information items are different from a part thereof recoded in any other second routing table; and the first routing table reads from the transfer information items of the second routing tables only transfer information items belonging to a destination used for an information transfer operation and transfer information items belonging to a group to which the destination belongs, from the second routing tables keeping the transfer information items.