Patent ID: 7106735

Claim:
A multicast packet transfer system comprising: a first packet transfer apparatus which transmits transfer packet data relating to an IP header and a UDP header of a multicast packet when said multicast packet is received, rewrites a header section of said multicast packet to produce a unicast packet, and transmits said unicast packet; and a second packet transfer apparatus which receives said transfer packet data and said unicast packet, and reproduces said multicast packet based on the received unicast packet and the received transfer packet data, wherein, said first packet transfer apparatus comprises i) a transmitting section which produces said transfer packet data based on the received multicast packet to transmit to said second packet transfer apparatus, ii) a header rewriting section which rewrites said header section of said multicast packet based on said transfer packet data to produce said unicast packet, iii) a packet transferring section which transfers said unicast packet to said second packet transfer apparatus, and iv) a first transfer packet data table which stores said transfer packet data, said transfer packet data includes said IP header and said UDP header of the received multicast packet and a number of a port of said first packet transfer apparatus corresponding to said IP header and said UDP header, said header rewriting section searches said first transfer packet data table based on said IP header and said UDP header of the received multicast packet to retrieve said port number when said port number is registered in said first transfer packet data table in correspondence to said IP header and said UDP header, and rewrites said header section of said multicast packet using said port number to produce said unicast packet, and said header rewriting section selects an unused port of said first packet transfer apparatus when any port number corresponding to said IP header and said UDP header of the received multicast packet is not searched, sets a number of the selected unused port as said port number, and stores the set port number in said first transfer packet data table in correspondence to said IP header and said UDP header.