MOBILE COMMUNICATION METHOD AND SYSTEM UTILIZING IP NETWORK

摘要

PROBLEM TO BE SOLVED: To realize a seamless data transmission (hand-over) using an IP address in a mobile host roaming within a plurality of subnets. SOLUTION: While paying attention to a multicast address to be used commonly among a large number of hosts, a transmitting source host 202 transmits data to a moving host 201 in a multicast packet. When the mobile host 201 roams from a cell 211 to a cell 212, on the other hand, the delivery of the received multicast packet to both cells 211 and 212 is requested to an upstream router 203 and after the mobile host enters the cell 212, it is reported to the router 203 that it is not necessary to deliver the multicast packet to the cell 211.