The invention discloses a technique to efficiently realize a routing based on preference of a mobile terminal in case the mobile terminal is connected to a mobility management domain of network base different from a home network domain. According to this technique, a mobile terminal (mobile node; MN) 101 has two interfaces, and these interfaces are connected to a mobility management domain (local mobility domain) 11 under the condition that these interfaces are connected to MAG 111 and MAG 112 respectively. In case MN itself decides one of the interfaces to be used for a specific packet flow communication, a routing preference to instruct that the packet flow is to be sent on a routing via the interface is notified to MAG. When MAG notifies the routing preference to LMA (filtering agent) 110, filtering based on the routing preference is carried out.