JP2005252997A - Communication system, communication method, communication program, recording medium, and mobile router - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To construct private networks that are movable and share the same network address. <P>SOLUTION: A home agent HA in a communication system including the home agent HA of a broadband network 10, mobile routers MR and nodes N of private networks 12 is characterized by including a location correspondence table BC managing correspondence between a network address and a c/o address CoA, being configured to specify a mobile router MR having a network address of a node N of a communication destination in communication between nodes N, requesting a search for determining whether or not the specified mobile router MR has the address of the node N of the communication destination, to said mobile router, and being configured to specify the mobile router MR including the node N of the communication destination from a result of the search request. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a communication system, a communication method, a communication program, a recording medium, and a mobile router.

  Portable mobile devices have become widespread due to the miniaturization of computers and power-saving technologies. By attaching a communication function to these mobile devices, for example, it is possible to send and receive mail at a business trip destination. A technique for connecting a mobile device to a wide area network such as the Internet has been proposed as MobileIP in the Internet Engineering Task Force (IETF), which is an Internet standardization organization (Non-Patent Document 1, etc.).

  MobileIP is a mechanism in which a router device called a home agent manages the correspondence between identification information (home address) of a mobile device and the latest location information (care-of address) of the mobile device. The communication partner of the mobile device communicates using the home address, and the home agent converts the home address and the care-of address to make the mobile device communication partner aware of the movement of the position of the mobile device. It is possible to perform communication without using it.

  However, MobileIP requires each mobile device to register the latest location information independently. Therefore, there is a problem that a terminal that does not have a MobileIP function (location information registration function) cannot be used by connecting to a wide area network. Therefore, instead of each mobile device performing the latest location information registration process, a device that relays the communication of the mobile device called a mobile router performs the registration of the latest location information. (Nonpatent literature 2 etc.).

NEMO realizes movement in units of networks by registering the correspondence information between the address of the network to which each mobile device belongs and the care-of address assigned to the mobile router with the home agent each time the movement is made. Thus, since only the mobile router has a function of registering location information with the home agent, an existing mobile device that does not support MobileIP can be used by connecting to the wide area network.
The Internet Engineering Task Force (IETF), “Mobility Support in IPv6”, [online], [searched on February 13, 2004], Internet <URL: http://www.ietf.org/internet-drafts/draft -ietf-mobileip-ipv6-24.txt> The Internet Engineering Task Force (IETF), “Network Mobility (NEMO) Basic Support Protocol”, [online], [searched on February 17, 2004], Internet <URL: http://www.ietf.org/internet -drafts / draft-ietf-nemo-basic-support-02.txt>

  On the other hand, the utilization method in which an individual or the like connects private mobile devices owned by the individual to construct a private network and uses the private network for data sharing or the like is widespread. These private networks are called PAN (Personal Area Network). Then, on business trips, there is an increasing need for taking out a part of a group of mobile devices that make up a private network and using the mobile devices taken out.

  In an application in which a part of a private network device group is taken out, the same network address is assigned to the device group constituting the same private network before the device group is taken out. The devices can communicate with each other within the same network address. Therefore, after being taken out, the same network address is assigned to the part of the private network that has been taken out and the remaining part of the private network that has not been taken out. . In order for the mobile device group to be able to communicate, the latest location information of each of the taken-out private network and the remaining private network is registered with the home agent via the mobile router of the private network. The Rukoto.

  However, in the conventional NEMO, it is not assumed that the home agent accepts registration of the same network address from a plurality of different mobile routers. This is because when the home agent manages the correspondence between the care-of address of the mobile router and the network address under the mobile router, if one network address is associated with a plurality of care-of addresses, the registered network address This is because it becomes impossible to specify which care-of address should be transmitted to the mobile router.

  Thus, conventional NEMO assumes that one network address is associated with one care-of address. However, according to the specification, the taken-out private network and the remaining private networks cannot share the same network address, and it takes time to change the network address of one private network. In that case, in addition to the trouble of setting the change of the network address, the communication between the mobile device whose network address has been changed and the communication partner terminal is interrupted.

  Therefore, the main object of the present invention is to solve the above-mentioned problems and to construct a private network that is movable and shares the same network address.

In order to solve the above problem, the communication system according to claim 1 is a communication system for performing communication between movable private networks via a wide area network, and the communication system is connected to the wide area network. A home agent to be connected; a mobile router that relays data communication between the wide area network and the private network; and a node connected to the private network.
The home agent accepts registration from the mobile router and manages the correspondence between the network address of the private network under the mobile router and the care-of address for the mobile router to access the wide area network. Have a table,
In the communication between the nodes, the home agent refers to the network address stored in the position correspondence table with the network address including the communication destination node as a key, and determines the mobile router including the communication destination node. Has a specific configuration,
The home agent makes a search request to the specified mobile router to determine whether or not it has an address of a communication destination node, and specifies the mobile router including the communication destination node based on a result of the search request It is comprised so that it may carry out.

  As a result, the home agent can identify the destination node in cooperation with the mobile router. Therefore, it is possible to construct a private network that is movable and shares the same network address.

  The communication system according to claim 2 is the communication system according to claim 1, wherein the home agent updates a position correspondence registration unit that updates the position correspondence table, and a position that searches for data in the position correspondence table. Logical search between a correspondence search unit, a node location search requesting unit that requests a search as to whether or not the mobile router has an address of the communication destination node, and the mobile router having an address of the communication destination node And a tunnel setting unit for creating a communication path.

  As a result, the home agent can identify the destination node in cooperation with the mobile router. Therefore, it is possible to construct a private network that is movable and shares the same network address.

  The communication system according to claim 3 is the communication system according to claim 2, wherein the home agent has information on the mobile router having an address of the node of the communication destination acquired by the node location search request unit. Is further configured to include a node location search notification unit that notifies the mobile router of the communication source.

  As a result, the home agent can identify the destination node in cooperation with the mobile router. Therefore, it is possible to construct a private network that is movable and shares the same network address.

  The communication system according to claim 4 is the communication system according to claim 3, wherein the home agent is a plurality of destination data received from the source mobile router other than the source mobile router. A packet communication unit for transferring to a mobile router registered in the position correspondence table is further included.

  As a result, the communication system can be applied not only to unicast communication destined for a single terminal, but also to communication (multicast, broadcast, etc.) destined for a plurality of terminals.

The invention described in claim 5 and claim 15 is a network information storage in which the mobile router grasps the existence of a node under the private network to which the mobile router belongs, and stores the care-of address and the grasped node. A care-of address update unit that updates the care-of address,
Whether a predetermined node is included with reference to the location registration unit that registers the correspondence between the care-of address and the network address of the private network to which the mobile router belongs in the home agent and the network information storage unit A node location search notifying unit that searches for the result and notifies the result,
It is characterized by comprising.

  As a result, the home agent can identify the destination node in cooperation with the mobile router. Therefore, it is possible to construct a private network that is movable and shares the same network address.

  The communication system according to claim 6 is the communication system according to claim 5, wherein when the mobile router receives data from the node, the mobile router sends a destination of data to the node. A proxy response indicating that the node is a node, requests the home agent to search for the destination of the data, and identifies the mobile router that is the destination of the data based on the result of the request from the home agent It is characterized by comprising.

  As a result, the home agent can identify the destination node in cooperation with the mobile router. Therefore, it is possible to construct a private network that is movable and shares the same network address.

  The communication system according to claim 7 is the communication system according to claim 6, wherein the mobile router performs logical communication with the mobile router that is a transmission destination of the data. And a tunnel setting unit for creating a simple communication path.

  Thereby, since the mobile router receives the notification of the mobile router that is the communication partner from the home agent, the mobile routers can directly communicate data with each other without going through the home agent.

  The communication system according to claim 8 is the communication system according to claim 7, wherein the mobile router relays communication of a node connected to the mobile router when the care-of address is invalid. It is characterized by operating as a bridge.

  As a result, by using the mobile router as a bridge device, the number of network devices required for the private network can be reduced, and the cost can be reduced.

  The communication system according to claim 9 is the communication system according to claim 7, wherein the mobile router has an invalid care-of address and no node connected to the mobile router. It is characterized by shifting to an inactive state.

  Thereby, the power saving of the mobile router is realized.

  A communication system according to a tenth aspect is the communication system according to the first aspect, wherein the home agent and the mobile router are housed in the same casing. .

  Thereby, the number of housings required for the entire communication system can be reduced, and the cost can be suppressed.

The communication method according to claim 11 includes a home agent connected to a wide area network, a mobile router that relays data communication between the wide area network and the private network, and a node connected to the private network. A communication method using a communication system for performing communication between movable private networks via the wide area network,
A procedure in which the home agent accepts and manages registration from the mobile router with respect to the correspondence between the network address of the private network under the mobile router and the care-of address for the mobile router to access the wide area network; ,
In the communication between the nodes, the home agent refers to the network address stored in the position correspondence table with the network address including the communication destination node as a key, and the mobile router including the communication destination node is referred to. Steps to identify,
A procedure in which the home agent transmits data to the mobile router including the communication destination node, which is obtained as a result of a search request for the address of the communication destination node performed with respect to the identified mobile router; , Is executed.

  As a result, the home agent can identify the destination node in cooperation with the mobile router. Therefore, it is possible to construct a private network that is movable and shares the same network address.

The communication method according to claim 12 includes a home agent connected to a wide area network, a mobile router that relays data communication between the wide area network and the private network, and a node connected to the private network. A communication method using a communication system for performing communication between movable private networks via the wide area network,
A procedure in which the home agent accepts and manages registration from the mobile router with respect to the correspondence between the network address of the private network under the mobile router and the care-of address for the mobile router to access the wide area network; ,
In the communication between the nodes, the home agent refers to the network address stored in the position correspondence table with the network address including the communication destination node as a key, and the mobile router including the communication destination node is referred to. Identifying and notifying the private mobile router that contains the source node;
The mobile router that has received the notification executes a procedure for transmitting data to the mobile router including the communication destination node.

  Thereby, since the mobile router receives the notification of the mobile router that is the communication partner from the home agent, the mobile routers can directly communicate data with each other without going through the home agent.

  The present invention is characterized in that a home agent and a mobile router cooperate to specify a destination node. As a result, it is possible to construct a private network that is movable and shares the same network address.

  By constructing such a private network, the network can be used efficiently. In other words, since communication between personal devices with many burst communications such as printing and file synchronization can be confined within the personal segment, not only the personal environment but also the performance of the entire network can be expected.

  Further, by constructing such a private network, the network administrator has conventionally been required to manage the address assignment to each device, but the address block (or IPv4) for the same user. In this case, the number of objects to be managed can be greatly reduced by assigning one address for NAT (Network Address Translation).

  Also, by constructing such a private network, filtering can be performed at the segment boundary router at the entrance / exit of the personal environment, so that it is possible to improve security in both the personal environment / the entire network. For example, even if the user introduces an infectious virus such as Blaster, the affected area can be localized.

  Furthermore, by constructing such a private network, organizational changes and dynamic cross-organizational project construction can be facilitated. That is, even when individual devices are separately connected to the network, it is easy to construct and set a CUG (Closed User Group) between the segment boundary routers.

  By constructing a movable network, the mobile router has a network under its control, connects to the Internet such as a wireless LAN / PHS at the destination, and provides Internet connectivity to the devices under control. In addition, the mobile router realizes seamless (that is, no interruption of communication) network handover (switching of base stations) corresponding to switching of communication media (for example, from wireless LAN to PHS) when a location changes.

  In addition, due to the construction of a movable network, the mobile router provides an environment equivalent to being directly connected to the personal network segment at the destination. That is, the mobile router realizes automatic setting of network devices under its control, communication between the mobile environment and devices remaining in the personal network segment, and the like.

  Hereinafter, an embodiment of a communication system to which the present invention is applied will be described in detail with reference to the drawings. First, the configuration of the communication system of the present embodiment will be described with reference to FIGS.

  FIG. 1 is a configuration diagram of a communication system. The communication system shown in FIG. 1 is a network to which a moving network or a partner device that communicates with a moving network device belongs to a wide area network 10 that connects a plurality of networks such as the Internet. A private network 12 is connected. The communication system includes an access router AR that issues a care-of address for the connected router to access the wide area network, and a home agent HA that manages the latest location information about the private network.

  When the private network 12 pays attention to the movement of the network, the private network 12 is a partner related to a network to which a device that is a communication partner between the mobile network MN related to the physically moved network and the private network device on the mobile side belongs. And the side network CN.

  Furthermore, the private network 12 is a router that relays between the wide area network 10 and the private network 12, and includes a mobile router MR that changes an access router to be connected by a handover accompanying the movement of the position, and another private network via the mobile router. A node N that communicates with a network node is connected to the network by a network.

  Here, the mobile router MR has two types of addresses. The first address is an address assigned from the access router AR to the interface on the wide area network 10 side of the mobile router MR, and is used to uniquely determine the position of the mobile router MR in the wide area network 10. The care-of address CoA. The second address is an address assigned to the private network 12 side interface of the mobile router MR and the node N, and is a home address HoA which is an invariant address regardless of the physical movement of the device.

  FIG. 2 is a configuration diagram of the home agent. In order to perform processing related to location information, the home agent HA receives a location correspondence table BC that records the correspondence between the network address of the private network and the latest location information of the device, and an update request for the location correspondence table BC. The position correspondence registration unit 112 that registers new position correspondence information in the position correspondence table, the position correspondence search unit 114 that searches the predetermined correspondence data by accessing the position correspondence table BC, and the search for the position of the predetermined node are moved. A node location search requesting unit 120 that requests a router, and a node that specifies a mobile router of a private network that includes the predetermined node and notifies the result of the request for a search for the position of the predetermined node from the mobile router A position search notification unit 122. The position correspondence search unit 114 performs a search process using the network address as a search key as the correspondence data.

  Further, the home agent HA is configured to include a tunnel setting unit 126 that creates a tunnel that is a logical communication path according to a tunneling protocol and a packet communication unit 128 that transmits and receives packets in order to perform data communication. The The tunneling protocol is, for example, IPv6 over IPv6.

  FIG. 3 is a configuration diagram of the mobile router. The mobile router MR is connected to the network information storage unit 132 that stores a care-of address and a node under the private network to which the mobile router MR belongs, and the wide area network 10 as the device moves. A care-of address update unit 134 that updates the care-of address set in the interface, a node management unit 136 that grasps the existence of a node under the private network to which it belongs, a care-of address set according to the position of its own device, and a private address A location registration unit 138 that registers the correspondence with the network information in the home agent, and a private network registration unit 142 that registers the correspondence between the care-of address of the own device and the network address of the private network with the home agent. Configured.

  Further, the mobile router MR performs a process related to node position search, a node position search request unit 146 that requests a home agent to search for a predetermined node position, and a search for a predetermined node position from the home agent. In response to the request, a search is made as to whether or not a predetermined node is included in a node of the private network of the own device, and a node position search notification unit 148 for notifying the result, and the position of the predetermined node as the position of the own device And a node position search proxy response unit 150 that performs proxy response.

  Further, the mobile router MR is configured to include a tunnel setting unit 154 that creates a tunnel that is a logical communication path in accordance with a tunneling protocol and a packet communication unit 156 that transmits and receives packets in order to perform data communication. The

  FIG. 4 is a configuration diagram of the node. The node N communicates with a node in another private network via the mobile router MR, a node location search requesting unit 162 that requests the mobile router MR to search for a location of a predetermined node N, and the mobile router MR. The node management correspondence unit 164 corresponding to the node management and the packet communication unit 166 that transmits and receives packets are configured.

  Here, processing of the node management unit 136 and the node management support unit 164 will be described. The node management unit 136 and the node management support unit 164 communicate with each other using a predetermined protocol and exchange information regarding the nodes. Examples of the predetermined protocol include ARP (Address Resolution Protocol) and IPv6 ND (Neighbor Discovery). Then, the node management unit 136 prompts the node management support unit 164 to provide information regarding the node, and the node management support unit 164 provides the node management unit 136 with the information.

  Further, components related to node position search (node position search request unit 120, node position search notification unit 122, node position search request unit 146, node position search notification unit 148, node position search proxy response unit 150, node position search request) The unit 162) notifies the address of a node serving as a search key according to a protocol such as ND (Neighbor Discovery) in IPv6.

  The configuration of the communication system has been described above. Next, of the operations of the communication system according to the present embodiment, the location registration process to the home agent will be described with reference to FIGS. 1 to 4 and FIG.

  FIG. 5 is a flowchart showing the location registration process with the home agent. First, each mobile router MR confirms the existence of the node N and the node N (S101). Note that the existence of the node N may be confirmed not only once but also a plurality of times because the node N may leave the network. Next, each mobile router MR (internal network registration unit 142) registers the location correspondence including the subordinate network address in the home agent HA (S102). Then, the location correspondence registration unit 112 of the home agent HA registers the correspondence between the network address and the care-of address CoA of the mobile router MR in the location correspondence table BC.

  The position correspondence registration process in the position correspondence table BC is performed every time the care-of address CoA is changed. The care-of address CoA is changed by issuing a new care-of address CoA due to movement, disabling the interface that uses the care-of address CoA due to changes in the administrator's network settings, and using the care-of address CoA due to power-on. For example, enabling the interface.

  Furthermore, it is assumed that the mobile router MR of the mobile network MN and the subordinate node N move together with the network (S103). Then, the mobile router MR of the mobile network MN acquires the care-of address CoA from the access router AR and updates it with the address of the connection interface with the wide area network 10 (S104). Further, the mobile router MR (internal network registration unit 142) of the mobile network MN registers the location correspondence including the network address in the home agent HA (location correspondence registration unit 112) (S105).

  Here, data registered in the position correspondence table BC will be described. FIG. 6 is a diagram illustrating an example of a configuration of a communication system. In the communication system shown in FIG. 6, the private network 12 whose network address is AAA is composed of a counterpart network CN and a mobile network MN. The counterpart network CN is configured by a mobile router MR1, a node N1, and a node N2. The mobile network MN is configured by a mobile router MR2, a node N3, and a node N4. Then, the mobile router MR1 is connected to the access router AR1 via the care-of address CoA1. The mobile router MR2 before movement is connected to the access router AR2 via the care-of address CoA2, and the mobile router MR2 after movement is connected to the access router AR3 via the care-of address CoA3.

  FIG. 7 is a configuration diagram of the position correspondence table BC in the communication system shown in FIG. Before the movement of the mobile router MR2, the home agent HA sets the network address (AAA) under the control of the mobile router MR1 (care-of address CoA1) and the network address (AAA) under the control of the mobile router MR2 (care-of address CoA2). Registration is performed by notification from each mobile router MR (see FIG. 7A). Then, as the mobile router MR2 moves, the home agent HA changes the corresponding care-of address from the care-of address CoA2 to the care-of address CoA3 for registration of the network address (AAA) under the control of the mobile router MR2 (FIG. 7). (See (B)).

  The content of the position correspondence table BC in FIG. 7 of this embodiment is different from the NEMO of the prior art. In other words, the NEMO of the prior art does not adopt a configuration in which the same network address (AAA) is associated with a plurality of care-of addresses (CoA1 and CoA2) as shown in FIG. On the other hand, the present embodiment is configured to permit the same network address (AAA) to be associated with a plurality of care-of addresses (CoA1 and CoA2). However, the communication protocol used for location registration may be a new protocol, or a protocol that conforms to the format used for NEMO of the prior art or an existing routing protocol. May be. By using a protocol according to the NEMO format, the existing implementation can be utilized, so that development costs can be reduced and smoothing can be performed when standardization is promoted.

  Further, as shown in FIG. 7, an expiration date from the record registration time may be provided for each position-corresponding record. Then, the home agent HA deletes the record whose expiration date has passed from the position correspondence table BC. Further, the home agent HA accepts registration from the mobile router MR again for the record of the position correspondence table BC within the validity period, and extends the validity period when the registration is made. Thereby, even if the mobile router MR breaks down and communication is interrupted, the record regarding the failed mobile router MR is automatically deleted as time passes. For this reason, it is possible to suppress the continuous transmission of data to the failed mobile router MR.

  The location registration process with the home agent has been described above. Next, of the operation of the communication system according to the present embodiment, data communication processing will be described with reference to FIGS. 1 to 7 and FIGS. 8 and 9.

  Here, the mobile router MR and the node N for explaining FIGS. 8 and 9 are defined. First, in order to describe the processing using the flowchart, the reference numerals of the communication system in FIG. 6 are used. 8 and 9 is not limited to the communication system of FIG. 6 with respect to the network configuration and the number of devices that are components of each network.

  8 and 9 show processing when nodes N that perform communication belong to networks under separate mobile routers MR. On the other hand, when the communicating nodes N belong to the network under the same mobile router MR, the direct communication is possible without going through the mobile router MR. Therefore, the processes of FIGS. 8 and 9 are performed. Absent.

  Consider a case where data communication is performed from the node N1 under the mobile router MR1 to the node N3 under the mobile router MR2. In that case, although the node N1 and the node N3 share the same network address, since the physical position is distant, it is necessary to communicate via the wide area network 10. Therefore, it is assumed that the home agent HA has received location registration from the mobile router MR1 and the mobile router MR2, respectively, as shown in FIG. Hereinafter, the process of FIG. 8 will be described.

  First, the mobile router MR1 receives from the node N1 a location search request message for searching for the node N3 (address AAA4). Then, the mobile router MR1 makes a proxy response to the node N1 indicating that the mobile router MR1 itself is the node N3 in the location search request message (S201). Here, the proxy response is performed by ProxyARP (in the case of IPv4), ProxyND (in the case of IPv6), or the like. Next, the mobile router MR1 requests the home agent HA to request a location search of the node N3 (S202).

  Then, the node location search requesting unit 120 of the home agent HA receives the location search request and requests the predetermined mobile router MR to search for the location of the node N3 (address AAA4) (S203). Here, the predetermined mobile router MR requesting the location search is a mobile router MR excluding the mobile router MR1 that has received the request, and is a mobile router MR having a network address (address AAA) to which the node N3 belongs. is there. The mobile router MR having a network address (address AAA) is acquired by the home agent HA searching the location correspondence table BC.

  Then, each mobile router MR requested to perform the location search performs a search process to determine whether the node 3 designated by the location search is included in the nodes of each subordinate network. Here, the node search process is a process in which the mobile router MR searches the network information storage unit 132 using the address of the node 3 as a key. Then, the mobile router MR2 that has found the node N3 notifies the home agent HA that the node N3 has been found (S204).

  Here, the mobile router MR1 receives data addressed to the node N3 from the node N1 (S205). This is because the data addressed to the node N3 reaches the mobile router MR1 when the mobile router MR1 makes a proxy response in S201. Then, the mobile router MR1 transfers data addressed to the node N3 to the home agent HA (S206).

  Further, the home agent HA transfers the data addressed to the node N3 to the mobile router MR2 notified in S204 (S207). Then, the mobile router MR2 transfers the data addressed to the node N to the destination node N (S208).

  FIG. 9 is a diagram illustrating communication processing in which the route of the communication system has been optimized. First, the processing related to the node position search is the same as in FIG. That is, S201 and S301, S202 and S302, S203 and S303, and S204 and S304 are the same processing, and the description thereof is omitted.

  The home agent HA (node location search notification unit 122) that has received the notification from the mobile router MR2 in S304 sends the address of the mobile router MR2 that is the search result of the node N to the mobile router MR1 that has transmitted the location search request. Notification is made (S305).

  Here, the mobile router MR1 receives data addressed to the node N3 from the node N1 (S306). Then, the mobile router MR1 transfers data addressed to the node N3 to the mobile router MR2 (S307). Here, since the mobile router MR1 has received the notification of the mobile router MR2 as the communication partner in S305, the mobile router MR can directly communicate data with each other without going through the home agent HA.

  Then, the mobile router MR2 transfers the data addressed to the node N3 received from the mobile router MR1 to the destination node N3 (S308).

  The present invention described above can be widely modified without departing from the spirit of the invention as follows.

  For example, the present invention can be applied not only to unicast communication destined for a single terminal, but also to communication (multicast, broadcast, etc.) destined for a plurality of terminals. First, the mobile router MR that has received a packet destined for a plurality of terminals transfers the packet to the home agent HA. Next, the home agent HA specifies the mobile router MR that is the destination of the received packet, and transfers the packet to the mobile router MR. Further, each mobile router MR that receives the packet transfers the packet to the node N of each subordinate network.

  Here, regarding the identification of the mobile router MR that is the transmission destination of the packet, the home agent HA sets all the mobile routers MR other than the mobile router MR that has received the packet as the transmission destination mobile router MR. Next, the home agent HA narrows down mobile routers MR as transmission destinations according to packet types (multicast, broadcast, IPv4, IPv6, etc.). For example, when the packet type is broadcast, the mobile router MR having the network designated as the transmission destination of the packet is specified as the destination mobile router MR with reference to the position correspondence table BC. In another example, when the packet type is multicast, the mobile router MR having the multicast group designated as the packet destination is selected as the destination mobile router MR.

  Also, it is assumed that the mobile router MR of the present invention is not connected to the access router AR (that is, not connected to the wide area network using the care-of address). For example, FIG. 10 shows a configuration of a private network 12 including two mobile routers MR (mobile router MR8 and mobile router MR9). Among them, since the mobile router MR8 is connected to the access router AR, it relays data communication between the wide area network 10 and the private network 12. When the private network 12 moves, the private network 12 is registered with the home agent HA. On the other hand, the mobile router MR9 is not directly connected to the wide area network 10 because it is not connected to the access router AR.

  In this case, the mobile router MR9 is connected to the mobile router MR8. The connection format between the mobile router MR9 and the mobile router MR8 may be, for example, a connection via a cable such as UTP (Unshielded Twist Pair cable), or the other mobile router MR in the slot of one mobile router MR. It is good also as a form which connects housings directly like inserting MR as a cartridge.

  When the mobile router MR9 accommodates at least one node N (FIG. 10 shows an example of two nodes), the mobile router MR9 transmits the private network 12 via the packet communication unit 156 for the accommodated node N. An operation for relaying data communication within the network (operation as a bridge) may be performed. As a result, the mobile router MR9 can also function as a bridge device, so that the number of network devices required for the private network 12 can be reduced and the cost can be reduced.

  On the other hand, when the mobile router MR9 does not accommodate any node N (that is, when only the mobile router MR8 is connected to the mobile router MR9), the mobile router MR9 does not need to perform data communication. Since there is not, it may shift to an inoperative state such as turning off the power.

  Further, in the communication system of FIG. 1 and the like, the home agent HA and the mobile router MR have been described as separate devices. However, the home agent HA and the mobile router MR are incorporated by incorporating the functions of the home agent HA into the mobile router MR. May be configured as one housing. In that case, the number of housings required for the entire communication system can be reduced, and costs can be reduced.

It is a block diagram of the communication system regarding one Embodiment of this invention. It is a block diagram of the home agent regarding one Embodiment of this invention. It is a block diagram of the mobile router regarding one Embodiment of this invention. It is a block diagram of the node regarding one Embodiment of this invention. It is a flowchart which shows the position registration process to the home agent regarding one Embodiment of this invention. It is a figure which shows an example of a structure of the communication system regarding one Embodiment of this invention. It is a block diagram of the position correspondence table regarding one Embodiment of this invention. It is a figure which shows the communication processing of the communication system regarding one Embodiment of this invention. It is a figure which shows the communication process by which the path | route optimization of the communication system regarding one Embodiment of this invention was made. It is a block diagram of the communication system in the case of operating the mobile router regarding one Embodiment of this invention as a bridge.

Explanation of symbols

AR access router BC Location correspondence table (storage means)
CN partner side network CoA care-of address HA home agent HoA home address MN mobile side network MR mobile router N node 10 wide area network 12 private network 112 location correspondence registration unit 114 location correspondence search unit 120 node location search request unit 122 node location search notification unit 126 tunnel setting unit 128 packet communication unit 132 network information storage unit 134 care-of address update unit 136 node management unit 138 location registration unit 142 private network registration unit 146 node location search request unit 148 node location search notification unit 150 node location search proxy response unit 154 Tunnel setting unit 156 Packet communication unit 162 Node location search request unit 164 Node management support unit 166 Packet communication unit

Claims (15)

A communication system for performing communication between movable private networks via a wide area network, the communication system comprising: a home agent connected to the wide area network; and data between the wide area network and the private network A mobile router that relays communication, and a node that is connected to the private network.
The home agent accepts registration from the mobile router and manages the correspondence between the network address of the private network under the mobile router and the care-of address for the mobile router to access the wide area network. Have a table,
In the communication between the nodes, the home agent refers to the network address stored in the position correspondence table with the network address including the communication destination node as a key, and determines the mobile router including the communication destination node. Has a specific configuration,
The home agent makes a search request to the specified mobile router to determine whether or not it has an address of a communication destination node, and specifies the mobile router including the communication destination node based on a result of the search request A communication system characterized by being configured to do so.   The home agent includes a location correspondence registration unit that updates the location correspondence table, a location correspondence search unit that retrieves data of the location correspondence table, and whether the mobile router has an address of the node of the communication destination. The node location search requesting unit for requesting a search and a tunnel setting unit for creating a logical communication path with the mobile router having the address of the node of the communication destination are included. The communication system according to 1.   The home agent further includes a node location search notification unit for notifying the mobile router of the communication source of information related to the mobile router having the address of the node of the communication destination acquired by the node location search request unit. The communication system according to claim 2.   The home agent further includes a packet communication unit that transfers a plurality of destination data received from a communication source mobile router to a mobile router registered in the location correspondence table other than the communication source mobile router. The communication system according to claim 3, wherein the communication system is configured as follows. The mobile router includes a node management unit that grasps the presence of a node under a private network to which the mobile router belongs, a network information storage unit that stores the care-of address and the grasped node, and a care-of address that updates the care-of address. Update section,
Whether a predetermined node is included with reference to the location registration unit that registers the correspondence between the care-of address and the network address of the private network to which the mobile router belongs in the home agent and the network information storage unit A node location search notifying unit that searches for the result and notifies the result,
The communication system according to claim 1, comprising:   When the mobile router receives the data from the node, it sends a proxy response to the node that the mobile router is the data transmission destination node, and searches the home agent for the data transmission destination. 6. The communication system according to claim 5, wherein the communication router is configured to specify the mobile router that is a transmission destination of the data based on a result of the request from the home agent.   The mobile router further includes a tunnel setting unit that creates a logical communication path for performing data communication with the mobile router that is a transmission destination of the data. Item 7. The communication system according to Item 6.   The communication system according to claim 7, wherein the mobile router operates as a bridge that relays communication of a node connected to the mobile router when the care-of address is invalid.   8. The communication system according to claim 7, wherein the mobile router shifts to an inoperative state when the care-of address is invalid and there is no node connected to the mobile router.   The communication system according to claim 1, wherein the home agent and the mobile router are configured to be housed in the same casing. A home agent connected to a wide area network, a mobile router that relays data communication between the wide area network and the private network, and a node connected to the private network are configured via the wide area network. A communication method by a communication system for performing communication between movable private networks,
The home agent accepts registration from the mobile router and stores it in the storage means for the correspondence between the network address of the private network under the mobile router and the care-of address for the mobile router to access the wide area network. And the steps to
In the communication between the nodes, the home agent identifies the mobile router including the communication destination node by referring to the network address stored in the storage unit using the network address including the communication destination node as a key. And the steps to
A procedure in which the home agent transmits data to the mobile router including the communication destination node, which is obtained as a result of a search request for the address of the communication destination node performed with respect to the identified mobile router; The communication method characterized by performing these. A home agent connected to a wide area network, a mobile router that relays data communication between the wide area network and the private network, and a node connected to the private network are configured via the wide area network. A communication method by a communication system for performing communication between movable private networks,
The home agent accepts registration from the mobile router and stores it in the storage means for the correspondence between the network address of the private network under the mobile router and the care-of address for the mobile router to access the wide area network. And the steps to
In the communication between the nodes, the home agent identifies the mobile router including the communication destination node by referring to the network address stored in the storage unit using the network address including the communication destination node as a key. And a procedure for notifying the private network mobile router including the source node,
The communication method, wherein the mobile router that has received the notification executes a procedure for transmitting data to the mobile router including the communication destination node.   A communication program for causing a computer to execute the communication method according to claim 11 or 12.   A computer-readable recording medium on which the communication program according to claim 13 is recorded. A mobile router in a communication system comprising a home agent connected to a wide area network, a mobile router that relays data communication between the wide area network and a private network, and a node connected to the private network. There,
A node management unit that grasps the existence of nodes under the private network to which it belongs;
A network information storage unit that stores the care-of address and the grasped node; a care-of address update unit that updates the care-of address;
A location registration unit that registers the correspondence between the care-of address and the network address of the private network to which the mobile router belongs, in the home agent;
A node location search notification unit that refers to the network information storage unit to search whether a predetermined node is included and to notify the result;
A mobile router that is configured to include

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