Home agent selection method in mobile host support from multicasting environment

摘要

PURPOSE: A method for selecting a home agent under a mobile host support multicasting environment is provided to prevent traffic excess due to multicast datagram tunneling from the home agents of all the terminals belonging to a multicast group by selecting one among the mobile nodes of a multicast group so that only the home agent of the appointed mobile node can execute multicast datagram tunneling. CONSTITUTION: A GGSN(Gateway GPRS Support Node)/FA(Foreign Agent) appoints a forwarding agent and a backup forwarding agent among a plurality of home agents which mobile terminals, belonging to a multicast group, belong to(S110). In case that a signal to request the GGSN/FA to receive a multicast message is received from a home agent(S112), the GGSN/FA judges whether the home agent is the forwarding agent or the backup forwarding agent(S114). If the home agent is the forwarding agent, the GGSN/FA receives the multicast message(S124) and forwards it to a multicast group member(S126). However, if the home agent is the backup forwarding agent, the GGSN/FA receives the multicast message(S118) and judges whether a message has been received from the forwarding agent(S120). If a message has been received, the GGSN/FA discards the multicast message(S122). However, if a message has not been received, the GGSN/FA forwards the received multicast message to a multicast group member(S126).