Patent ID: 7529244

Claim:
A routing processing device which identifies one or a plurality of types of packet formats, and performs routing processing for each packet type, comprising: a packet information extraction portion, which extracts from a received packet for identification a prescribed range of fields including at least one identifying information item which identifies the received packet type as tagged IPv4 packet, untagged IPv4 packet, tagged IPv6 packet or untagged IPv6 packet; a packet judgment portion, which judges whether the received packet is a tagged packet or an untagged packet based on an identified first information item in a first pre-specified position in the extracted range of fields, including a value of tag or not, and (a) if the received packet is the tagged packet, identifying a second information item in a second pre-specified position in the extracted range of fields, and (a-1) if the second information item includes a length identifier, identifying a third information item in a third pre-specified position in the extracted range of fields, determining a type of the received packet as tagged IPv4 packet or not, based on the third information item, (a-2) if the second information item lacks a length identifier, identifying the second information item, determining a type of the received packet based on the second information item as tagged IPv6 packet or tagged IPv4 packet, (b) if the received packet is the untagged packet, (b-1) if the first information item includes a length identifier, identifying a fourth information item in a fourth pre-specified position in the extracted range of fields, determining a type of the received packet as tagged IPv4 packet, untagged IPv6 packet or a packet other than these, based on the fourth information item, (b-2) if the first information item lacks a length identifier, identifying the first information item, determining a type of the received packet based on the second information item as untagged IPv6 packet or tagged IPv4 packet; a header imparting portion, which creates header information according to the received packet type based on the judgment result of said packet judgment portion and imparts the header information to the packet; a packet sorting portion which sorts packets based on said header information imparted to the packets; and, a routing processing portion which performs routing processing of packets sorted by said packet sorting portion, according to the received packet type.