JP2010193356A - Communication system, home agent apparatus, and communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for speeding up a handover process in a mobile communication system. <P>SOLUTION: A foreign agent apparatus relays communication data sent and received by a mobile terminal and a home agent apparatus of the mobile terminal existing in its network, using a tunnel between the foreign agent apparatus and the home agent apparatus. The home agent apparatus presets a static tunnel between the home agent apparatus and the foreign agent apparatus and sends or receives the communication data to or from the mobile terminal using the static tunnel set between the home agent apparatus and the foreign agent apparatus in the network where the mobile terminal exists. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mobile communication system using mobile IP technology.

  There is a Mobile IP (MIP) technique as a technique for providing mobility to a mobile terminal at an IP (Internet Protocol) level. In recent years, applications that perform real-time communication such as video conferencing and IP telephones are increasingly used via mobile communication systems using MIP.

  In MIP, a Home Agent (HA) for each mobile terminal manages the location of the mobile terminal on the network, and transfers a communication packet in communication between the mobile terminal and the server. In addition, there is a Foreign Agent (FA) for relaying communication packets between the destination mobile terminal and the HA on a subnet basis.

  When the mobile terminal is in a different network (subnet) from the HA, a logical MIP tunnel is set between the FA and HA of the network where the mobile terminal is located, and the FA transmits communication packets transmitted and received between the mobile terminal and the HA. Relay using MIP tunnel. Thereby, when the mobile terminal moves between networks, communication can be continued at the destination even without changing the IP address.

  In order to realize these, when moving between networks, the mobile terminal notifies the HA of the movement and the new position to the HA by a Registration Request (RRQ) signal. When the HA receives the RRQ signal, it registers the new location of the mobile terminal. Then, the HA establishes the MIP tunnel between itself and the FA at the new location, and deletes the MIP tunnel between the source FA that has been used so far. Thereafter, the HA transmits / receives the communication packet of the mobile terminal to / from the new FA at the destination using the new MIP tunnel.

  In addition to the above-described tunneling, in Patent Document 1, a static tunnel is set in advance, and if data transfer is required due to movement of a wireless terminal, communication data is transferred using the static tunnel. A technique for transferring is disclosed. However, the configuration disclosed in Patent Document 1 does not assume HA, but a static tunnel is set in advance between an access router serving as a movement source and an access router serving as a movement destination. is there.

JP 2007-251249 A

  As described above, normally, in a mobile communication system using MIP, when a mobile terminal moves between networks, it is notified that the mobile terminal moves to the HA, and the HA sets the destination MIP tunnel and moves. A series of procedures is performed to delete the original MIP tunnel. The process for establishing the MIP tunnel takes a considerable amount of time.

  For this reason, the mobile terminal cannot perform data communication until the mobile terminal is able to communicate on the destination network after the mobile terminal moves between networks until the destination MIP tunnel is established. It is conceivable that real-time communication such as a voice call is interrupted.

  When providing mobile services using next-generation high-speed wireless communications such as mobile WiMAX (Worldwide Interoperability for Microwave Access), high-speed switching with minimal impact on applications between networks is required. .

  An object of the present invention is to provide a technique for speeding up a handover process in a mobile communication system.

In order to achieve the above object, the communication system of the present invention provides:
A foreign agent device that relays communication data transmitted and received between the mobile terminal existing in its own network and the home agent device of the mobile terminal using a tunnel between the home agent device,
A static tunnel is set in advance with the foreign agent device, and communication data with the mobile terminal is transmitted using the static tunnel set up with the foreign agent device of the network where the mobile terminal exists. And a home agent device for transmitting and receiving.

A home agent device of the present invention is a home agent device that transmits and receives communication data to and from a mobile terminal using a tunnel set up with a foreign agent device of a network in which the mobile terminal exists,
Static tunnel setting means for setting a static tunnel in advance with the foreign agent device;
Data transfer means for transmitting / receiving communication data to / from the mobile terminal using a static tunnel set up with a foreign agent device of a network in which the mobile terminal exists.

The communication method of the present invention includes:
A static tunnel is set in advance between the home agent device to which the mobile terminal belongs and the foreign agent device of the network to which the mobile terminal is connected,
The mobile terminal and the home agent device transmit and receive communication data using a static tunnel set between the foreign agent device of the network where the mobile terminal exists and the home agent device of the mobile terminal. is there.

  According to the present invention, the handover process can be quickly performed and the relay of the communication packet at the destination can be started at an early stage.

It is a block diagram which shows the structure of the mobile communication system of this embodiment. It is a block diagram which shows the structure of the home agent apparatus by this embodiment. It is a block diagram which shows the structure of the mobile WiMAX system by a present Example. It is a sequence diagram which shows a series of operation | movement of the mobile WiMAX system by a present Example.

  Embodiments for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing the configuration of the mobile communication system of the present embodiment. Referring to FIG. 1, the mobile communication system includes foreign agent devices (FA) 12A to 12C and a home agent device (HA) 11. The mobile communication system includes a plurality of networks (subnets), and the foreign agent devices 12A to 12C are provided for the networks 13A to 13C. The foreign agent device 12A corresponds to the network 13A, the foreign agent device 12B corresponds to the network 13B, and the foreign agent device 12C corresponds to the network 13C. Each network 13 includes one or a plurality of radio base stations (not shown), and is connected to the mobile terminal 14 by the radio base stations.

  Although only one home agent device 11 is shown in FIG. 1, there are generally a plurality of home agent devices 11 in a mobile communication system, and each mobile terminal 14 has a description of the mobile terminal 14. Home agent device 11 is defined. The mobile terminal 14 communicates with another mobile terminal 14 or a terminal of another communication system via its home agent device 11.

  The foreign agent device 12 relays communication packets transmitted and received between the mobile terminal 14 existing in its own network 13 and the home agent device 11 of the mobile terminal 14 using a tunnel between the home agent device 11. For example, the foreign agent device 12A relays a communication packet transmitted and received between the mobile terminal 14 and the home agent device 11 existing in the network 13A using a tunnel between the home agent device 11.

  The term tunnel here includes static tunnels and dynamic tunnels. The static tunnel is a tunnel that is set in advance between the home agent device 11 and the foreign agent device 12 before a communication packet relay between the mobile terminal 14 and the home agent device 11 is requested. The dynamic tunnel is a tunnel that is set when relay of a communication packet between the mobile terminal 14 and the home agent device 11 is started, and is released when the relay of the communication packet is completed.

  The home agent device 11 sets a static tunnel in advance with each foreign agent device 12, and sets the static tunnel set with the foreign agent device 12 of the network 13 in which the mobile terminal 14 exists. It uses to transmit and receive communication packets to and from the mobile terminal 14.

  As an example, the home agent device 11 may set all of the plurality of foreign agent devices 12A to 12C and static tunnels in advance. In that case, no dynamic tunnel is required.

  As another example, for each home agent device 11, a foreign agent device 12 for setting a static tunnel with the home agent device 11 may be selected. For example, it is determined that a static tunnel is set between the home agent 11 and the foreign agent devices 12A and 12B. In this case, the home agent device 11 may set a static tunnel between the home agent device 11 and the foreign agent devices 12A and 12B that are predetermined for the home agent device 11.

  When the home agent apparatus 11 moves to the network 13 of the foreign agent apparatuses 12A and 12B that have set up a static tunnel with the home agent apparatus 11 itself, the home agent apparatus 11 communicates with the communication packet via the static tunnel. Relay. At this time, the home agent device 11 transmits the communication data of the mobile terminal 14 to and from the foreign agent devices 12A and 12B on the condition that the mobile terminal 14 is registered in the network of the foreign agent devices 12A and 12B. It is also possible to send and receive via a static tunnel set to.

  In addition, when the mobile terminal 14 moves to the network 13 of the foreign agent device 12C that does not set a static tunnel with the home agent device 11 itself, the home agent device 11 newly establishes a dynamic tunnel with the foreign agent device 12C. And relay the communication packet through the dynamic tunnel.

  As another example, the home agent device 11 pre-sets a static tunnel with the foreign agent device 12 of the network 13 around the network 13 when the mobile terminal 14 exists in any network 13. Also good. For example, when the mobile terminal 14 exists in the network 13A, the home agent device 11 presets a static tunnel with the foreign agent device 12B of the network 13B around the network 13A. In that case, when the mobile terminal 14 moves to the surrounding network 13B, the relay of the communication packet may be started using the static tunnel set in the foreign agent device 12B of the destination network 13B.

  FIG. 2 is a block diagram showing the configuration of the home agent device according to the present embodiment. Referring to FIG. 2, it has a static tunnel setting unit 21 and a data transfer unit.

  The static tunnel setting unit 21 sets a static tunnel in advance with the foreign agent device 12.

  For example, in the mobile communication system, there may be a management device (not shown) that manages foreign agent information that defines the foreign agent device 12 that should set a static tunnel for each home agent device 11. Then, the home agent device 11 may acquire foreign agent information from the management device at the time of activation, and set a static tunnel according to the information.

  The data transfer unit 22 transmits / receives communication data to / from the mobile terminal 14 using a static tunnel set up with the foreign agent device 12 of the network 13 in which the mobile terminal 14 exists.

  For example, when the mobile terminal 14 moves from one network 13 (movement source) to another network 13 (movement destination), the registration request signal for requesting the home agent device 11 to register the location in the new network 13. May be sent. Upon receiving the registration request signal, the data transfer unit 22 registers the location of the mobile terminal 14 in the destination network 13. Thereafter, the data transfer unit 22 transfers the communication packet of the mobile terminal 14 via a tunnel with the foreign agent device 12 of the network 13 where the mobile terminal 14 has registered its location.

  As described above, according to the present embodiment, a static tunnel is set in advance between the home agent device 11 and the foreign agent device 12, and the static tunnel corresponding to the network 13 in which the mobile terminal 14 exists is set. Since the communication packet is used and relayed, when the mobile terminal 14 moves between the networks 13, the handover process can be quickly performed and the relay of the communication packet at the destination can be started at an early stage.

  With the recent increase in memory and CPU resource capacity, even if a tunnel is statically set in advance between the home agent device 11 and the foreign agent device 12, it does not cause a heavy load on the system or a large load. It is possible to operate so as not to become. In addition, the processing load is reduced because it is not necessary to repeatedly establish and release the tunnel dynamically. Further, by simplifying the handover process, the probability of occurrence of a software execution problem such as remaining resources without being released is reduced.

  Further, in this embodiment, when a static tunnel is set in advance for a predetermined foreign agent device 12, and the mobile terminal 14 moves to the network 13 of the foreign agent device 12 in which the static tunnel is set, By relaying communication data through the static tunnel, it is possible to speed up the handover of a network that is required to be speeded up efficiently.

  Further, in this embodiment, by setting a static tunnel in advance for the network 13 around the network 13 in which the mobile terminal 14 exists, the handover can be efficiently speeded up.

  In the present embodiment, the home agent device 11 can acquire the foreign agent information from the management device at the time of startup, and can set up a static tunnel in accordance with the information to centrally manage the foreign agent information. The update can be easily performed.

  In this embodiment, the home agent device 11 relays the communication data of the mobile terminal 14 through the static tunnel of the foreign agent device 12 of the network 13 on the condition that the mobile terminal 14 has been registered. The communication packet of the unauthorized mobile terminal 14 is not communicated.

  Hereinafter, examples in which the present embodiment is more specific will be described.

  In the present embodiment, mobile WiMAX is shown as an example of a system that provides mobility of a mobile terminal in a mobile service of high-speed wireless communication using the Mobile IP protocol.

  FIG. 3 is a block diagram showing the configuration of the mobile WiMAX system according to the present embodiment. Referring to FIG. 3, the mobile WiMAX system includes HA 31, FA 32, AAA (Authentication, Authorization, Accounting) server 35, and maintenance terminal 36.

  The HA 31 is a home agent device that manages location information of the mobile terminal 34. The HA 31 executes location registration and user authentication processing in response to a request from the mobile terminal 34, and relays a communication packet of user data of the mobile terminal 34 using a MIP tunnel between itself and the FA 32. As a result, the mobile terminal 34 can access the Internet 37, for example.

  The FA 32 is a foreign agent device that is provided for each of the plurality of networks 33 and relays a communication packet of user data of the mobile terminal 34 through an MIP tunnel with the HA 31.

  The AAA server 35 holds FA information of all FAs that accommodate users, and also holds user profile information of all users that the mobile WiMAX system provides communication services. The FA information is used when the HA 31 sets up a static MIP tunnel at startup. The user profile information is used when the HA 31 performs user authentication.

  The maintenance terminal 36 is a terminal for an operator to monitor, maintain, or operate the mobile WiMAX system. The operator can view or change FA information held in the HA 31 from the maintenance terminal 36.

  Information on the FA (FA information) for which the MIP tunnel is to be established is held in the AAA server 35, and the HA sets a static MIP tunnel according to the FA information at the time of activation. In the FA information, the IP address of the target FA for establishing the MIP tunnel is set, and the HA sets a static MIP tunnel in advance using the IP address of the FA and the IP address of the own HA. By using this static MIP tunnel at the time of handover, the processing speed can be increased.

  In this embodiment, a range in which a mobility service that allows movement of the mobile terminal 34 is provided is determined in advance, and the HA 31 sets a static MIP tunnel with the FA 32 in the mobility providing range. There are two methods for the HA 31 to grasp the FA 32 existing in the network in the mobility service provision range as FA information in advance.

  One is a method in which a maintenance command for setting a static MIP tunnel is defined, and an operator provides it to the HA as system information data.

  The other is a method of storing FA information in the AAA server 35 that manages user profiles and service provision operation policies. The HA 31 may acquire FA information from the AAA server 35 and set a static MIP tunnel based on the FA information. In order to flexibly set the configuration and state of the entire mobile communication system, a method using the AAA server 35 is preferable, and this example illustrates this.

  In this embodiment, a static MIP tunnel is set in advance instead of dynamically setting a MIP tunnel between the HA 31 and the FA 32 every time an RRQ is received.

  At the start of communication, an RRQ for requesting location registration is sent from the mobile terminal 34 to the HA 31 via the FA 32. The HA 31 that has received the RRQ from the mobile terminal 34 authenticates the user of the mobile terminal 34. If the authentication is OK, the HA 31 registers the location of the mobile terminal 34 in the network 33 of the FA 32 and completes registration with the FA 32. Returns Registration Reply (RRP). This RRP is transferred from the FA 32 to the mobile terminal 34. Thereafter, the transfer of the communication packet at the end of the mobile end 34 is started by a static MIP tunnel set in advance. That is, there is no need to dynamically set a MIP tunnel at the start of communication.

  At the time of handover, an RRQ for requesting location registration is sent from the mobile terminal 34 to the HA 31 via the destination FA 32. The HA 31 that has received the RRQ via the destination FA 32 registers the location of the mobile terminal 34 in the network 32 of the FA 32 and returns an RRP of registration completion to the FA 32. This RRP is transferred from the FA 32 to the mobile terminal 34. Thereafter, the transfer of the communication packet of the mobile terminal 34 is started by the static MIP tunnel set in advance at the destination. That is, the process of dynamically setting a new MIP tunnel and the process of opening the MIP tunnel that has been used until then are not required at the time of handover.

  In this embodiment, the HA 31 sets a static MIP tunnel in advance, but there is no binding cache (BC) that is the location registration information of the mobile terminal 34, that is, the location of the mobile terminal is registered. In the absence, the user data communication packet is not transferred through the MIP tunnel. This is to prevent unregistered users from using the service illegally from the viewpoint of security.

  Further, in actual operation of the mobile communication system, it is assumed that the FA 32 that is a target for setting a static MIP tunnel is required to be added or removed during service operation. On the other hand, in this embodiment, two methods for updating the FA information are prepared.

  One is that the operator inputs a maintenance command from the maintenance terminal 36 to the HA 31 to update the FA information. The other is to update the FA information managed by the AAA server 35 and distribute it to the HA 31, and the HA 31 starts operation with new FA information from the AAA server 35.

  Next, an operation example of the mobile WiMAX system of this embodiment will be described. FIG. 4 is a sequence diagram showing a series of operations of the mobile WiMAX system according to the present embodiment. Here, it is assumed that there are three FAs 32, FA # 1 to FA # 3, and FA # 1 to FA # 3 correspond to networks # 1 to # 3, respectively. The mobile terminal 34 starts communication on the network # 1, and moves to the network # 2 while continuing communication.

  The HA 31 notifies the AAA server 35 of system activation at the time of activation (step 101), and acquires FA information from the AAA server 35 (step 102). This FA information is also notified to the HA 31 at the timing when the FA information held by the AAA server 35 is updated. Furthermore, in order to prevent the FA information of the AAA server 35 and the FA information of the HA 31 from being inconsistent, the AAA server 35 may notify the HA 31 periodically (periodically).

  The HA 31 sets an MIP tunnel based on the FA information acquired from the AAA server 35 (step 103). Here, it is assumed that the HA 31 sets MIP tunnels in all the FAs 32 (FA # 1 to FA # 3). Up to here, it is executed in advance when the system is started.

  As described above, the MIP tunnel is set in advance when the system is started. However, the HA 31 transmits a communication packet of user data through the MIP tunnel in the state where the binding cache (BC) that is the location registration information of the mobile terminal 34 does not exist. Never forward.

  Thereafter, when the mobile terminal 34 is activated in the network # 1 (step 104), the mobile terminal 34 transmits an RRQ to the HA 31 via the FA # 1 (steps 105 and 106). The HA 31 performs user authentication using the AAA server 35 holding the user profile (step 107).

  Since MIP tunnel # 1 has already been set, if authentication is successful (step 108), HA 31 returns RRP to mobile terminal 34 via FA # 1 (steps 109 and 110). Thereby, the location registration of the mobile terminal 34 is completed.

  When the location registration of the mobile terminal 34 is completed, for example, when the mobile terminal 34 is connected to the Internet 37, communication of user data is started via the MIP tunnel # 1 as shown in FIG.

  Here, the mobile terminal 34 moves from the network # 1 to the network # 2 while continuing communication (step 112). The mobile terminal 34 transmits RRQ to the HA 31 via FA # 2 (steps 113 and 114). Since MIP tunnel # 2 has already been set, HA 31 immediately returns RRP to mobile terminal 34 via FA # 2 (steps 115 and 116). Thereby, the location registration of the mobile terminal 34 is completed.

  When the location registration of the mobile terminal 34 is completed, as shown in FIG. 4, the communication of user data is switched to pass through the MIP tunnel # 2.

  Various variations can be considered in the present embodiment described above.

  In the present embodiment, an example has been shown in which all user data communication is handled by a static MIP tunnel. However, the present invention is not limited to this. As another example, a static MIP tunnel and a dynamic MIP tunnel may be used in combination.

  Depending on the application, there are some applications that do not pose a problem even if communication is temporarily interrupted while moving, or that do not require real-time communication. It is also conceivable that the real-time property of communication can be selected by contract in association with charge setting. In such a case, a static MIP tunnel may be used for some applications or users that require real-time communication, and a dynamic MIP tunnel may be used for other applications or users.

  In the present embodiment, an example in which static MIP tunnels are set in advance for all the FAs 32 in the mobility provision range is shown. However, the present invention is not limited to this. If a static MIP tunnel is maintained for all the FAs 32 and resource consumption becomes excessive, a static MIP tunnel is set only for a predetermined FA 32, and other FAs 32 are used when necessary. A dynamic MIP tunnel may be set or released. For example, a static MIP tunnel may be set in advance only in the FA 32 of a network that requires high-speed handover. While maintaining the real-time service provision area, it is possible to keep the system resource utilization efficiency appropriate.

  In the present embodiment, an example in which a static MIP tunnel is set when the system is started up is shown, but the present invention is not limited to this. As another example, a MIP tunnel is not set when the system is started, and when a MIP tunnel is set for a certain FA 32, a static MIP tunnel is established for the FA 32 of the network 33 around the network 33 of the FA 32. May be. This can be realized by predetermining a network 33 around each network 33 in advance. In addition, the MIP tunnel with the FA 32 of the network 33 that does not correspond to the surrounding network 33 due to the movement of the mobile terminal 34 may be released. When the mobile terminal 34 moves between the networks 33, it is only necessary to use a preset MIP tunnel of the destination network 33, so that handover processing can be performed quickly while efficiently using resources. it can.

  It is also possible to realize ancillary services by utilizing the functions of the system of this embodiment.

  For example, it is possible to provide a local service corresponding to the position to the mobile terminal 34. A location-related service to be provided to the mobile terminal 34 existing in the network 33 of the FA 32 is determined for the location of the FA 32. Further, the FA information held by the HA 31 includes location information indicating the location of each FA 32. Then, the HA 31 uses the location information included in the FA information of the FA 32 to which the communication packet is transferred using the static MIP tunnel, and the mobile terminal 34 existing in the network 33 of the FA 32. Provide location related services.

  As mentioned above, although embodiment and the Example of this invention were described, this invention is not limited only to these embodiment or an Example, In the range of the technical idea of this invention, these are combined. It may be used or a part of the configuration may be changed.

11, 31 HA
12, 32 FA
13, 33 Network 14, 34 Mobile terminal 35 AAA server 36 Maintenance terminal 37 Internet 21 Static tunnel setting unit 22 Data transfer unit

Claims (15)

A foreign agent device that relays communication data transmitted and received between the mobile terminal existing in its own network and the home agent device of the mobile terminal using a tunnel between the home agent device,
A static tunnel is set in advance with the foreign agent device, and communication data with the mobile terminal is transmitted using the static tunnel set up with the foreign agent device of the network where the mobile terminal exists. And a home agent device for transmitting and receiving.   The communication system according to claim 1, wherein there are a plurality of foreign agent devices, and the home agent device presets all the foreign agent devices and the static tunnel in advance.   The home agent device presets the static tunnel with a foreign agent device predetermined for the home agent device, and the mobile terminal is statically connected with the home agent device of the mobile terminal. When the mobile terminal moves to the foreign agent device network in which the static tunnel is set, the communication data is relayed through the static tunnel, and the mobile terminal is connected to the static tunnel between the mobile terminal and the home agent device. 2. The communication according to claim 1, wherein the foreign agent device and the home agent device newly set a tunnel and relay communication data through the tunnel when moving to a network of foreign agent devices to which no is set. system.   The home agent device sets the static tunnel between a foreign agent device and a home agent device of a network around the network when the mobile terminal exists in any network. The communication system described.   The communication system according to any one of claims 1 to 3, wherein the home agent device sets a static tunnel according to foreign agent information indicating a foreign agent device to which the static tunnel is to be set when the home agent device is started. A management device for managing the foreign agent information;
The communication system according to claim 5, wherein the home agent device acquires the foreign agent information from the management device and sets up a static tunnel according to the foreign agent information when activated. A location-related service to be provided to a mobile terminal existing in the network of the foreign agent device is defined for the location of the foreign agent device,
The foreign agent information held by the home agent device includes location information indicating the location of the foreign agent device,
The home agent device includes a location included in the foreign agent information of the foreign agent device in which the static tunnel is set for a mobile terminal to which a communication packet is to be transferred using a static tunnel. The communication system according to claim 5 or 6, wherein a location-related service is provided based on the location information.   The home agent device is configured so that the mobile terminal communicates communication data of the mobile terminal with the foreign agent device on the condition that the mobile terminal is registered in the network of the foreign agent device. The communication system according to any one of claims 1 to 7, wherein the communication system transmits and receives data. A home agent device that transmits and receives communication data to and from the mobile terminal using a tunnel set up with a foreign agent device of a network in which the mobile terminal exists,
Static tunnel setting means for setting a static tunnel in advance with the foreign agent device;
A home agent device comprising: data transfer means for transmitting and receiving communication data to and from the mobile terminal using a static tunnel set up with a foreign agent device of a network in which the mobile terminal exists. There are a plurality of foreign agent devices,
The home agent device according to claim 9, wherein the static tunnel setting unit sets all the foreign agent devices and the static tunnel in advance. The static tunnel setting means sets the static tunnel in advance with a foreign agent device predetermined for the home agent device,
The data transfer means relays communication data through the static tunnel when the mobile terminal moves to a network of foreign agent devices in which a static tunnel is set up with the home agent device. , When the mobile terminal moves to a foreign agent device network in which no static tunnel is set up with the home agent device, the foreign agent device and the home agent device newly set up a tunnel, The home agent device according to claim 9, wherein communication data is relayed through the tunnel.   The home agent device according to claim 9, wherein the static tunnel setting unit sets the static tunnel with a foreign agent device in a network around the network when the mobile terminal exists in any network.   The static tunnel setting means sets a static tunnel according to foreign agent information indicating a foreign agent device to which the static tunnel is to be set when the home agent device starts up. The home agent device described in 1.   The static tunnel setting means acquires the foreign agent information from a management device that manages the foreign agent information when the home agent device starts up, and sets a static tunnel according to the foreign agent information. The home agent device described. A static tunnel is set in advance between the home agent device to which the mobile terminal belongs and the foreign agent device of the network to which the mobile terminal is connected,
A communication in which the mobile terminal and the home agent device transmit and receive communication data using a static tunnel set between the foreign agent device of the network in which the mobile terminal exists and the home agent device of the mobile terminal Method.

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