PACKET COMMUNICATION SYSTEM

The present invention provides a packet communication system has a mobile host, a home agent, a correspondent host, and a mobility agent, wherein the mobility agent operates in such a way that in the case of an active mode and no need for buffering of packet, the mobility agent forwards a packet received from the home agent or the correspondent host, to the mobile host, that in the case of the active mode and necessity for buffering of packet, the mobility agent buffers the packet, and that in the case of an idle mode, the mobility agent buffers the packet and notifies the mobile host of arrival of the packet, in order to prevent the loss of a packet addressed to a mobile host, to decrease the traffic of Binding Update packets, to decrease the transmission frequency of Binding Update packets where the mobile host sends or receives no packet for a long period of time, and to send a packet a destination of which is a node present at a mobile network.