Communication System, Mobile Terminal and Access Router

摘要

A new technique is disclosed, by which a mobile terminal executing handover between subnets can quickly transmit packet to outside immediately after the handover. According to this technique, MN (mobile node) 10 executing the handover requests an external transmission address relating to a subnet connected after the handover (a link local address of an access router or of a default router belonging to the subnet after the handover) when transmitting an FNA message to NAR 31 connected immediately after the handover. In response to the request, NAR acquires the external transmission address and transmits the external transmission address to MN by sending an RA message to MN. MN sets up the external transmission address acquired before the handover to the packet to be transmitted after the handover.