Continuity of route optimization during handover from network-based mobility to host-based mobility

An object of the present invention is to provide such handover method of a mobile node. A place correspondent node to the mobile node to perform proxy route optimization performs handover from the current access network to the target access network, it is necessary to perform proxy route optimization after the handover or the judges. If necessary, run the route optimization based on the return routability, to determine whether to perform a route optimization based on the home. When performing route optimization based on the return routability, information about the proxy route optimization is sent to the mobile node by the home agent. When performing route optimization based on the home agent, the route optimization state of the mobile node generates and managed by the home agent of the mobile node, updating the routing state of a communication partner node in the new location of the mobile node to. .FIELD 8