Abstract: A new technique is disclosed, by which a mobile terminal after executing handover between subnets can quickly perform packet transmission to outside immediately after the handover. According to this technique, after deciding the execution of handover, MN (mobile terminal) 10 requests an external transmission address (link local address of an access router belonging to a subnet or of a default router after the handover) relating to a subnet connected after the handover at the same time as the transmitting of RtSolPr message to PAR21 connected before the handover. PAR acquires the external transmission address in response to the request and transmits the external transmission address to MN together with a response by PrRtAdv message to MN. MN sets up the external transmission address as acquired before the handover to the packet to be transmitted after the handover.

Abstract: This system provides for communications between several different types of wireless networks and a mobile node. The system provides various services from a wireless network to a mobile node which is not covered by that wireless network without exhaustion of the mobile node battery. According to this system, the mobile node sends an update message to a currently accessible network node, which transfers the update message to the same or different types of nearby network nodes with incrementing the hop count for every transfer. The different type of network node that has received the update message checks whether the hop count decreases from that previously received, judges that the mobile node is approaching if the hop count decreases, and sends the guide message to the mobile node via the same and different types of networks.

Abstract: 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 NAR31 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.

Abstract: For communications between several different types of wireless networks and a mobile node, technology to provide various services from a wireless network to the mobile node which is not covered by that network without exhaustion of the mobile node battery is disclosed. According to this technology, the mobile node sends an update message to a currently accessible network node, which transfers the update message to the same or different types of nearby network nodes with incrementing the hop count for every transfer. The different type of network node that has received the update message checks whether the hop count decreases from that previously received and judges that the mobile node is approaching if the hop count decreases and sends the guide message to the mobile node via the same and different types of networks.

Abstract: There is disclosed a technique capable of lessening the delay which can occur in a conventional FMIP (fast handover technique) and of reducing packet loss. According to this technique, upon receipt of an FBAck message from a PAR (access router to which a mobile terminal (MN) 10 has a connection before handover) 21 (step S113), an NAR (access router to which the MN makes a connection after the handover) 31 temporarily stores this FBAck message (step S119). Moreover, Upon receipt of an FNA message including an FBU message from the MN (step S121), the NAR 31 refers to the FBAck message stored in the step S119 so as to make a collation with the FBU message in the FNA message (step S125) and, if the corresponding FBAck message exists, it transmits a packet, addressed to the MN and buffered, to the MN (step S127).

Abstract: A new technique is disclosed, by which a mobile terminal after executing handover between subnets can quickly perform packet transmission to outside immediately after the handover. According to this technique, after deciding the execution of handover, MN (mobile terminal) 10 requests an external transmission address (link local address of an access router belonging to a subnet or of a default router after the handover) relating to a subnet connected after the handover at the same time as the transmitting of RtSolPr message to PAR21 connected before the handover. PAR acquires the external transmission address in response to the request and transmits the external transmission address to MN together with a response by PrRtAdv message to MN. MN sets up the external transmission address as acquired before the handover to the packet to be transmitted after the handover.

Abstract: 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 NAR31 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.

Abstract: A technique which realizes an efficient handover by reducing loads on a mobile node and an access router and communication traffics thereof while keeping a packet loss rate in a fast handover technology is disclosed, and according to that technique, a mobile node (MN 10) has a correspondence relationship between information (link layer address of an AP) on an access point (AP 22, 23, 32, 33) and information (link layer address of an AR, and a network prefix and a prefix length of a subnet 20, 30 to which the AR belongs) on an access router (AR 21, 31) having control over the AP, and, by referring to the correspondence relationship, generates an NCoA of a subnet which is the destination of movement in L2 handover between different subnets, does not change an NCoA and executes only the L2 handover in the L2 handover in the same subnet, and performs a conventional fast handover when there is no correspondence relationship relating to an AP at the destination of the L2 handover.