Patent ID: 7079502

Claim:
A packet communication system comprising: a plurality of terminals, and transferring means for transferring multicast packets written with the same information to said plurality of terminals; wherein said transferring means comprises: a broadcast group managing router provided with: holding means for holding calculation type addresses having bits “1” corresponding to those of said plurality of terminals to which a multicast packet is to be transferred, respectively; and assigning/sending means for assigning a pertinent calculation type address to a multicast packet and sending out the multicast packet; and at least one calculation type address calculating router provided with: holding means for holding directional route masks having bits “1” corresponding to those directional routes into which a multicast packet is to be transferred, respectively; and sending means for sending out a multicast packet to those directional routes which are given with logical products of “1” by the combination of each directional route mask and said assigned calculation type address; and wherein each of said plurality of terminals comprises: holding means for holding a terminal mask having a bit “1” corresponding to the terminal itself; and multicast packet receiving means for receiving a multicast packet which is given with a logical product of “1” by the combination of said terminal mask and said assigned calculation type address.