JP2004007072A - Network address management device, program thereof, and handover method in radio communications - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain continuous communication with the same device on the other end before and after handover by assigning the same IP address after the handover as that assigned before the handover when a client terminal as a movable node performs a handover operation in radio communication. <P>SOLUTION: A network address management device 10 is provided with a Bluetooth address / IP address correspondence database 16 and an IP address management portion 12. By being assigned with an IP address from an access point 30 (#1), the Bluetooth address / IP address correspondence database 16 stores an IP address assigned to a client terminal 20 making an access to the access point 30(#1) by Bluetooth radio communication. When the client terminal 20 performs a handover operation from the access point 30(#1) to an access point 30(#n), the IP address management portion 12 assigns the IP address stored in the Bluetooth address / IP address correspondence database 16 to the client terminal 20 requiring an access to the access point 30(#n). <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a communication network such as a LAN using a wireless communication system such as Bluetooth, for example, in which a client terminal or the like, which is a movable node, cannot continue communication with an access point being accessed and accesses another access point. The present invention relates to a network address management device, a network address management program, and a handover method in wireless communication that enable uninterrupted communication even when the communication is performed.
[0002]
[Prior art]
In the wireless communication system in Bluetooth, a study on standardization of a handover procedure has been made, but no study has been made on how to assign a network address such as an IP address at the time of the handover.
[0003]
At the time of handover in wireless communication, an IP address assignment method called Mobile IP is adopted so that a movable node such as a mobile terminal can continuously communicate with the same communication partner. According to this method, a movable node, not only in the same segment, but can move to any position in a network of any topology and continue to communicate with the same communication partner.
[0004]
In this case, nodes called home agents and foreign agents are placed in the network. By registering that the mobile node is a Mobile IP node in the home agent, the mobile node always performs address conversion via the home agent and communicates with the partner device. Therefore, from the viewpoint of the partner device, the communication is always performed with the IP address of the home agent.
[0005]
When the mobile node moves, it is registered as a Mobile IP node with the foreign agent, and a tunnel using the Mobile IP header is created between the foreign agent and the home agent. Since the mobile node performs address conversion and communicates with the partner device via the foreign agent, tunnel, and home agent, the mobile node is still communicating with the IP address of the home agent even after moving. With such a handover method in wireless communication, communication is continued without interruption even during handover.
[0006]
[Problems to be solved by the invention]
However, such a conventional handover method in wireless communication has the following problems.
[0007]
That is, in the case of a LAN constructed using a wireless communication system, if a client terminal, which is a movable node, performs a handover and changes an access point to be connected, the IP address of the client terminal also changes. For this reason, the partner device that was communicating before the handover does not know the IP address of the client terminal, and cannot communicate with the client terminal immediately after the handover.
[0008]
To prevent this from happening, the IP address assigned to the client terminal must be the same before and after the handover. As a method of assigning an IP address to such a client, there is an IP address assignment method using a PPP (Point to Point) server, and an IP address assignment method using a DHCP (Dynamic Host Configuration Protocol) server.
[0009]
However, the IP address assignment method using the PPP server and the IP address assignment method using the DHCP server have the following problems.
[0010]
That is, in the IP address assignment method by the PPP server, when the client terminal establishes a PPP connection with the PPP server in the access point when connecting to the access point, the PPP server uses the IPCP (Internet Protocol control protocol) to set up the client terminal. Is assigned an IP address. At this time, the IP address assigned by the PPP server must be different for each access point. Otherwise, the same IP address will be assigned to the client terminal by different PPP servers, so that the same IP address may be assigned to different client terminals when handover is not performed.
[0011]
On the other hand, in the IP address assignment method by the DHCP server, the DHCP server in the segment to which the access point is connected can assign the IP address to the client terminal using DHCP after the connection between the client terminal and the access point.
[0012]
In this case, the DHCP server does not assign an IP address used by another client terminal connected to an access point in the same segment. When the client terminal moves between access points by handover, the IP address used by the client terminal before the handover is released at the time of the handover. Therefore, there is a possibility that the same IP address is assigned from the DHCP server after the handover. However, in the DHCP server, it is not determined whether to use the released IP address immediately. Therefore, a different IP address may be assigned.
[0013]
As described above, the IP address assigned before and after the handover may be different. At this time, there is Mobile IP as a method for allowing the client terminal to continue communication with the same partner device.
[0014]
That is, in Mobile IP, if a client terminal is registered with a home agent, the same partner is assigned even if a different IP address is assigned as long as the client terminal is connected not only within a segment but also at a position where communication with the home agent is possible after handover. Can communicate continuously with the device.
[0015]
However, after the handover, a tunnel is created by the client terminal between the foreign agent and the home agent in the same segment as the connected access point. For this reason, the client terminal must follow the route of the client → the foreign agent → the home agent → the partner device regardless of the position of the home agent. The same applies to the case where the partner device of the communication destination is in the same segment as the client terminal, and the communication of the client terminal follows a circuitous route and increases the network load on the home agent side. There's a problem.
[0016]
The present invention has been made in view of such circumstances, and when a client terminal that is a movable node in wireless communication performs a handover, the same IP address assigned to the client terminal before the handover is used. It is an object of the present invention to provide a network address management device, a network address management program, and a handover method in wireless communication, in which an IP address is assigned even after a handover, thereby enabling continuous communication with the same partner device before and after the handover. And
[0017]
[Means for Solving the Problems]
In order to achieve the above object, the present invention takes the following measures.
[0018]
In other words, the network address management device according to the first aspect of the present invention is configured such that a node such as a mobile client terminal or the like accessing the first access point by wireless communication by being assigned a network address from the first access point. Storage means for storing a network address such as an IP address assigned to the second access point, when the node has handed over from the first access point to the second access point, And allocating means for allocating a network address stored in the storage means, and connected to a plurality of access points including first and second access points via a communication network.
[0019]
Therefore, in the network address management apparatus according to the first aspect of the present invention, the node (for example, the client terminal) uses the same network address (for example, the IP address) before and after the handover by taking the above means. Therefore, communication with the same partner device can be continued. As a result, communication can be performed with the shortest communication path without setting a connection to be a tunnel or changing a network address.
[0020]
The network address management device according to the second aspect of the present invention is configured such that a network address is allocated from a first access point, so that the network is allocated to a mobile node accessing the first access point by wireless communication. A storage unit for storing an address in association with an identification number given to the node in advance; and, when the node performs a handover from the first access point to the second access point, a self-address to the second access point. Allocating means for retrieving a network address stored in association with the notified identification number from the storage means for the node which has requested access by notifying the identification number, and allocating the searched network address to the node, Through the communication network And formed by connecting a plurality of access points including the second access point.
[0021]
Therefore, in the network address management device according to the second aspect of the present invention, by taking the above-described means, the node (for example, a client terminal) accessing any of the access points connected via the communication network can be provided. A network address such as an assigned IP address can be stored in association with a node-specific identification number such as a Bluetooth address or a serial number. When the node moves and hands over to another access point, the network address assigned before the handover can be assigned by notifying the newly accessed access point of its own identification number. it can.
[0022]
As a result, similarly to the first aspect of the present invention, it is possible to perform communication with the shortest communication path without setting a connection to be a tunnel or changing a network address.
[0023]
A handover method in wireless communication according to claim 3, wherein a mobile node is accessing a first access point by wireless communication by being assigned a network address from a first access point connected to a communication network. Handovers from the first access point to a second access point connected to the communication network, the second access point has the same network address that the first access point has assigned to the node. Network addresses are assigned to nodes.
[0024]
Therefore, in the handover method in wireless communication according to the third aspect of the present invention, by taking the above measures, the node such as the client terminal uses the same network address (for example, an IP address) before and after the handover. Therefore, communication with the same partner device can be continued. As a result, communication can be performed with the shortest communication path without setting a connection to be a tunnel or changing a network address.
[0025]
According to a fourth aspect of the present invention, in the handover method in wireless communication according to the third aspect of the present invention, the node has a unique identification number, and when the node accesses the first access point, it identifies itself. Notifying the number to the first access point, and the first access point, when notified of the identification number from the node, assigns a network address to the node and associates the network address assigned to the node with the identification number of the node. In a case where the node has handed over from the first access point to the second access point, the node stores its own identification number in the second access point. The second access point receives the identification number from the node. The network address stored in association with the notified identification number retrieved from the storage means, to allocate the retrieved network address to the node.
[0026]
Therefore, in the handover method in wireless communication according to the fourth aspect of the present invention, by taking the above means, a node (for example, a client terminal) accessing any of the access points connected via the communication network Can be stored in association with an identification number unique to the node, such as a Bluetooth address or a serial number. When the node moves and hands over to another access point, the network address assigned before the handover can be assigned by notifying the newly accessed access point of its own identification number. it can.
[0027]
As a result, similarly to the third aspect of the present invention, communication can be performed with the shortest communication path without setting a connection to be a tunnel or changing a network address.
[0028]
According to a fifth aspect of the present invention, a network address is assigned from a first access point connected to a communication network, so that the mobile node is assigned to a mobile node accessing the first access point by wireless communication. A first notification function for notifying a network address and an identification number given to a node in advance from a first access point, and storing the network address and the identification number notified in the first notification function in a database in association with each other A storage function for notifying, when a node has handed over from a first access point to a second access point connected to a communication network, an identification number previously assigned to the node is notified from the second access point The second notification function, the second notification function Search function for searching a network address stored in association with the identification number notified in the database from the database, and handing over the network address searched by the search function from the second access point to the second access point And a computer-readable network management program for causing a computer to realize a network address assignment function for assigning to a designated node.
[0029]
Therefore, in the network management program according to the fifth aspect of the present invention, by taking the above-described measures, the network management program assigns a node (for example, a client terminal) accessing any of the access points connected via the communication network. The network address such as the assigned IP address can be stored in association with an identification number unique to the node, such as a Bluetooth address or a serial number. When the node moves and hands over to another access point, the network address assigned before the handover can be assigned by notifying the newly accessed access point of its own identification number. it can. As a result, communication can be performed with the shortest communication path without setting a tunnel connection or changing a network address.
[0030]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
[0031]
FIGS. 1 to 3 are conceptual diagrams each showing an example of a network configuration to which a network address management device according to an embodiment of the present invention is applied. In each of FIGS. 1 to 3, a network address management device 10 and a plurality of access points 30 ( # 1, # 2,..., #N) are connected to each other via the LAN 18.
[0032]
FIG. 1 shows a state in which the client terminal 20 is making an access request to the access point 30 (# 1), and FIG. 2 shows a state in which the client terminal 20 accessing the access point 30 (# 1) performs a handover. FIG. 3 shows a state in which an access request is made to the access point 30 (#n). FIG. 3 shows that the client terminal 20 that has been accessing the access point 30 (#n) disconnects the access to the access point 30 (#n). It shows the status.
[0033]
Here, the network address is an address assigned to the network layer of the client terminal 20 accessing the access point 30, such as an IP address. In the embodiment of the present invention, a case where an IP address is applied as the network address will be described as an example. As a form of wireless communication between the client terminal 20 and the access point 30, Bluetooth (hereinafter, referred to as “BT”) will be described as an example.
[0034]
The client terminal 20 includes an IP address request unit 22 and a wireless communication unit 24, and accesses the access point 30 by BT connection. The IP address request unit 22 requests the access point 30 for an IP address necessary for the client terminal 20 to access the access point 30. When the user requests the access point 30 to acquire an IP address in this way, the user inputs a unique address, which is an identification number assigned in advance to the client terminal 20, from the IP address requesting unit 22, The IP address acquisition request information including the input unique address is transmitted to the access point 30 side. The unique address may be any address as long as it can identify the client terminal 20. For example, a link layer address such as a Bluetooth address (hereinafter, referred to as a “BT address”), a serial number of the client terminal 20, or the like may be used. . In the embodiment of the present invention, a case where a BT address is used as a unique address will be described.
[0035]
The wireless communication unit 24 transmits and receives data to and from the access point 30 by wireless communication using BT.
[0036]
The access point 30 includes a wireless communication unit 32, an IP address assignment unit 34, and an IP address acquisition unit 36. When the IP address acquisition request information is transmitted from the IP address request unit 22 of the client terminal 20 which is a BT client, the IP address assignment unit 34 transfers the IP address acquisition request information to the IP address acquisition unit 36. The IP address acquisition unit 36 requests the IP address to be assigned to the requesting client terminal 20 by transmitting the IP address acquisition request information to the network address management device 10.
[0037]
Here, the IP address acquisition unit 36 manages the network address by registering the IP address of the network address management device 10 in advance, or by registering the protocol between the network address management device 10 and the access point 30 in advance. The device 10 recognizes the device 10 and can transmit IP address acquisition request information to the recognized network address management device 10. Further, the IP address acquisition unit 36 receives the IP address notified from the network address management device 10 in response to such IP address acquisition request information, and transfers it to the IP address assignment unit 34.
[0038]
The IP address assignment unit 34 assigns the IP address transferred from the IP address acquisition unit 36 to the client terminal 20 that has requested the IP address, and transmits the IP address to the client terminal 20 side.
[0039]
The wireless communication unit 32 transmits and receives data to and from the wireless communication unit 24 of the client terminal 20.
[0040]
The network address management device 10 manages an IP address, which is a network address of the client terminal 20 accessing each access point 30, and executes a network address management program stored in a storage medium such as a magnetic disk. This is realized by a computer whose operation is controlled by the network address management program, and includes an IP address management unit 12, an IP address pool 14, and a Bluetooth address / IP address correspondence database 16 (hereinafter, referred to as a “BT address / IP address correspondence DB 16”). ").
[0041]
The IP address management unit 12 receives the IP address acquisition request information transmitted from the IP address acquisition unit 36. Then, the BT address / IP address correspondence DB 16 is searched for an IP address corresponding to the BT address included in the IP address acquisition request information.
[0042]
An example of the data configuration of the BT address / IP address correspondence DB 16 is as shown in FIG. 4, and is tabular data in which the BT address is associated with the corresponding IP address on a one-to-one basis. The one-to-one data written in the BT address / IP address correspondence DB 16 includes the BT address included in the access acquisition request information transmitted from the access point 30 to the network management device 10 and the BT address and the network address management device 10. Associates the IP address notified to the access point 30 and writes the IP address.
[0043]
Therefore, in the case of the client terminal 20 that has first made an access request to any of the plurality of access points 30 connected to the LAN 18, that is, the client terminal 20 that has newly made an access request to the access point 30, the BT address of this client terminal 20 is Not written in the BT address / IP address correspondence DB 16. In such a case, the IP address management unit 12 newly extracts one IP address corresponding to the BT address included in the access acquisition request information from the IP address pool 14, associates this IP address with the BT address, Write to the address / IP address correspondence DB16. Further, the IP address is returned to the access point 30.
[0044]
On the other hand, as shown in FIG. 2, the client terminal 20 accessing any one of the plurality of access points 30 (for example, the access point 30 (# 1)) connected to the LAN 18 performs another handover by handover. When an access request is made to the access point 30 (for example, the access point 30 (#n)), the IP address management unit 12 assigns the IP address corresponding to the BT address included in the access acquisition request information to the BT address / IP address correspondence. A search is made from the DB 16 and the searched IP address is returned to the access point 30 (#n).
[0045]
Thus, the IP address returned from the IP address management unit 12 to the access point 30 (#n) is once received by the IP address acquisition unit 36 (#n), and from there, the IP address assignment unit 34 (#n). ), And the IP address assignment unit 34 (#n) assigns the IP address transferred from the IP address acquisition unit 36 (#n) to the client terminal 20 that has requested the IP address. The IP address is assigned to the client terminal 20 by transmitting the IP address to the original client terminal 20 side. This allows the client terminal 20 to access the access point 30 (#n) and perform IP communication via the access point 30 (#n).
[0046]
Next, the operation of the handover method in wireless communication according to the embodiment of the present invention configured as described above will be described together with the operation of the network address management device.
[0047]
First, a case where the client terminal 20 accesses the access point 30 (# 1) will be described with reference to the conceptual diagram of FIG. 1 and the data transition diagram of FIG.
[0048]
When the client terminal 20 that has not accessed the access point 30 accesses the access point 30 (# 1) among the plurality of access points 30 (# 1 to #n) whose addresses are managed by the network address management device 10. Will be described as an example. In this case, first, the client terminal 20 makes a BT connection to the access point 30 (# 1) (S1).
[0049]
Next, the IP address request unit 22 transmits IP address acquisition request information to the access point 30 (# 1) so that the client terminal 20 accesses the access point 30 (# 1). This IP address acquisition request information includes a BT address, which is a unique address unique to the client terminal 20, and after being received by the IP address assignment unit 34 (# 1) of the access point 30 (# 1), The IP address is transferred from the IP address assignment unit 34 (# 1) to the IP address acquisition unit 36 (# 1) (S2). Further, the IP address acquisition request information is transmitted from the IP address acquisition unit 36 (# 1) to the network address management device 10, and received by the IP address management unit 12 of the network address management device 10 (S3).
[0050]
In the IP address management unit 12, an IP address corresponding to the BT address included in the IP address acquisition request information is extracted from the IP address pool 14 by the IP address management unit 12 (S4), and the BT address and the IP address correspond to each other. The IP address is written to the BT address / IP address correspondence DB 16 (S5), and the IP address is returned to the IP address acquisition unit 36 (# 1) (S7). The IP address returned from the IP address management unit 12 to the IP address acquisition unit 36 (# 1) is once received by the IP address acquisition unit 36 (# 1), and from there, the IP address assignment unit 34. The IP address is transferred to (# 1) (S7), and further returned from the IP address allocating unit 34 (# 1) to the IP address requesting unit 22 of the client terminal 20, whereby an IP address is allocated to the client terminal 20 (S8). ).
[0051]
The client terminal 20 accesses the access point 30 (# 1) using the IP address assigned in this way, and communicates with the other device (not shown) connected to the LAN 18 via the access point 30 (# 1). The data communication between them is performed (S9).
[0052]
Next, a case where the client terminal 20 accessing the access point 30 (# 1) performs a handover to the access point 30 (#n) will be described with reference to the conceptual diagram of FIG. 2 and the data transition diagram of FIG. .
[0053]
When the client terminal 20 accessing the access point 30 (# 1) performs a handover to the access point 30 (#n), first the access to the access point 30 (# 1) is released. In this case, the client terminal 20 releases the IP address without notifying the access point 30 (# 1), and then the wireless communication unit 24 disconnects the connection with the access point 30 (# 1) ( S11). Thereafter, the wireless communication unit 24 of the client terminal 20 performs a handover by making a BT connection with the wireless communication unit 32 (#n) of the access point 30 (#n) (S12).
[0054]
When the client terminal 20 connects to the access point 30 (#n) after the handover in this way, the IP address requesting unit 22 next transmits the client terminal 20 to the access point 30 (#n). The IP address acquisition request information is transmitted to the access point 30 (#n). This IP address acquisition request information includes a BT address which is a unique address unique to the client terminal 20. After the BT address is received by the IP address assigning unit 34 (#n) of the access point 30 (#n), The IP address is transferred from the IP address assignment unit 34 (#n) to the IP address acquisition unit 36 (#n) (S13). Further, the IP address acquisition request information is transmitted from the IP address acquisition unit 36 (#n) to the network address management device 10, and received by the IP address management unit 12 of the network address management device 10 (S14).
[0055]
Since the client terminal 20 has already been assigned an IP address from the access point 30 (# 1) whose address is managed by the network address management device 10, the BT address of this client terminal 20 and the corresponding IP address are It is written in the BT address / IP address correspondence DB 16. Therefore, based on the BT address included in the IP address acquisition request information, the IP address management unit 12 searches the BT address / IP address correspondence DB 16 for an IP address corresponding to the BT address (S15). The retrieved IP address is returned to the IP address acquisition unit 36 (#n). The IP address returned from the IP address management unit 12 to the IP address acquisition unit 36 (#n) is once received by the IP address acquisition unit 36 (#n), and from there, the IP address assignment unit 34. (#N) (S16), and the IP address is assigned to the client terminal 20 by being returned from the IP address assignment unit 34 (#n) to the IP address requesting unit 22 of the client terminal 20 (S17). ).
[0056]
The client terminal 20 accesses the access point 30 (#n) using the IP address allocated in this manner, and performs data communication between the client terminal 20 and the access point 30 (#n). (S18). Since this IP address is the same as the IP address assigned from the access point 30 (# 1) in step S8, the client terminal 20 was communicating via the access point 30 (# 1) before the handover. IP communication becomes possible again with a partner device (not shown), and data communication is continued.
[0057]
Finally, FIG. 3 is a conceptual diagram showing a case where the client terminal 20 accessing the access point 30 (#n) terminates the data communication and disconnects the connection with the access point 30 (#n). This will be described with reference to a data transition diagram of FIG.
[0058]
When the client terminal 20 releases access to the access point 30 (#n), the client terminal 20 transmits IP address release request information to the access point 30 (#n). The IP address release request information includes the BT address of the client terminal 20 and the IP address. The IP address release request information is received by the IP address allocating unit 34 (#n) of the access point 30 (#n). The data is transferred to the address acquisition unit 36 (#n) (S21).
[0059]
Then, the IP address acquisition unit 36 (#n) creates IP address deletion request information based on the IP address release request information, and transmits the created IP address deletion request information to the network address management device 10 (S22). ). The IP address deletion request information is received by the IP address management unit 12 of the network address management device 10, and the IP address management unit 12 extracts a BT address included in the IP address deletion request information. Further, an entry in which the extracted BT address is associated with the corresponding IP address on a one-to-one basis is deleted from the BT address / IP address correspondence DB 16 (S23), and the IP address deletion notification information is stored in the access point 30 ( #N). The returned IP address deletion notification information is received by the IP address acquisition unit 36 (#n), and further transferred to the IP address assignment unit 34 (#n) (S24).
[0060]
The IP address allocating unit 34 (#n) extracts the IP address from the IP address deletion notification information, creates IP address release completion information including the extracted IP address, and sends the IP address release completion information to the client terminal 20. Is returned. The returned IP address release completion information is received by the IP address request unit 22 (S25). Then, the connection between the wireless communication unit 24 of the client terminal 20 and the wireless communication unit 32 (#n) of the access point 30 (#n) is disconnected using the BT procedure (S26).
[0061]
The network address management device 10 described in the embodiment of the present invention can be realized by causing a computer to read a network address management program stored in a storage medium.
[0062]
Here, the storage medium in the present invention can store programs such as a magnetic disk, a floppy (registered commercial law) disk, a hard disk, an optical disk (CD-ROM, DVD, etc.), a magneto-optical disk (MO, etc.), a semiconductor memory, etc. As long as the storage medium is readable by a computer, the storage form may be any form.
[0063]
Also, an OS (Operating System) running on the computer, MW (Middleware) such as database management software, network software, etc., according to the instructions of the network address management program installed in the computer from the storage medium implements the present invention. A part of each processing for realizing the embodiment may be executed.
[0064]
Further, the storage medium in the present invention is not limited to a medium independent of a computer, but also includes a storage medium in which a network address management program transmitted via a LAN, the Internet, or the like is downloaded and stored or temporarily stored.
[0065]
Further, the number of storage media is not limited to one, and a case where the processing in the embodiment of the present invention is executed from a plurality of media is also included in the storage medium of the present invention, and the medium may have any configuration.
[0066]
The computer according to the present invention executes each processing in the embodiment of the present invention based on a network address management program stored in a storage medium, and includes a device such as a personal computer, a plurality of devices. May be any configuration such as a system connected to a network.
[0067]
Further, the computer in the present invention is not limited to a personal computer, but also includes an arithmetic processing unit, a microcomputer, and the like included in an information processing device, and generically refers to a device and a device capable of realizing the functions of the present invention by a network address management program. are doing.
[0068]
As described above, in the network configuration to which the network address management device according to the embodiment of the present invention according to the present embodiment is applied, since the handover method in wireless communication that operates as described above is applied, the client When the terminal 20 performs the handover, the same IP address as that assigned to the client terminal 20 before the handover can be allocated after the handover.
[0069]
As a result, it is possible to communicate with the shortest route without setting a connection to be a tunnel and without performing address conversion, so that it is possible to continuously communicate with the same partner device before and after the handover. Become.
[0070]
Although the preferred embodiments of the present invention have been described with reference to the accompanying drawings, the present invention is not limited to such configurations. Within the scope of the invented technical concept of the claims, those skilled in the art will be able to conceive various changes and modifications, and those changes and modifications will be described in the technical scope of the present invention. It is understood that it belongs to.
[0071]
【The invention's effect】
As described above, according to the present invention, when a client terminal which is a mobile node in wireless communication performs a handover, the same IP address as that assigned to the client terminal before the handover is handed over. Can be assigned later.
[0072]
As a result, it is possible to realize a network address management device, a network address management program, and a handover method in wireless communication that enable continuous communication with the same partner device before and after the handover.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing an example of a network configuration to which a network address management device according to an embodiment of the present invention is applied (when connected)
FIG. 2 is a conceptual diagram showing an example of a network configuration to which a network address management device according to an embodiment of the present invention is applied (at the time of handover);
FIG. 3 is a conceptual diagram showing an example of a network configuration to which the network address management device according to the embodiment of the present invention is applied (when disconnected);
FIG. 4 is a data configuration diagram showing an example of a Bluetooth address / IP address correspondence database;
FIG. 5 is a data transition diagram in a network configuration to which the network address management device according to the embodiment of the present invention is applied;
[Explanation of symbols]
10 Network address management device
12 ... IP address management unit
14 ... IP address pool
16 ... Bluetooth address / IP address correspondence database
18… LAN
20 ... Client terminal
22 ... IP address request section
24 ... Wireless communication unit
30 ... Access point
32 ... Wireless communication unit
34 ... IP address assignment unit
36 ... IP address acquisition unit

Claims (5)

Storage means for storing the network address assigned to the mobile node accessing the first access point by wireless communication by being assigned a network address from the first access point;
When the node has handed over from the first access point to the second access point, the network address stored in the storage means is sent to the node that has requested access to the second access point. Allocating means for allocating,
A network address management device connected to a plurality of access points including the first and second access points via a communication network. By assigning a network address from the first access point, the network address assigned to the movable node accessing the first access point by wireless communication is previously assigned to the node. Storage means for storing in association with the identification number;
When the node performs a handover from the first access point to a second access point, the node notifies the second access point of its own identification number to notify the node that has requested access to the node. Allocating means for retrieving a network address stored in association with the identified identification number from the storage means, and allocating the retrieved network address to the node,
A network address management device connected to a plurality of access points including the first and second access points via a communication network. By being assigned a network address from a first access point connected to a communication network, a mobile node accessing the first access point by wireless communication can receive the communication address from the first access point. When handing over to a second access point connected to a network, the second access point assigns to the node the same network address as the network address assigned to the node by the first access point. Handover method in wireless communication as described above. The handover method in wireless communication according to claim 3,
The node has a unique identification number, and when the node accesses the first access point, notifies the first access point of its own identification number;
3. The first access point, when notified of an identification number from the node, assigns a network address to the node, and associates the network address assigned to the node with an identification number of the node. 4. In the storage means of the network address management device of
If the node has handed over from the first access point to a second access point, the node informs the second access point of its own identification number;
When the second access point is notified of the identification number from the node, the second access point searches the storage unit for a network address stored in association with the notified identification number, and sends the searched network address to the node. A handover method in wireless communication to be assigned. Being assigned a network address from a first access point connected to a communication network, the network address being assigned to a mobile node accessing the first access point by wireless communication; and A first notification function for notifying from the first access point of an identification number previously assigned to the first access point;
A storage function for storing the network address and the identification number notified in the first notification function in a database in association with each other;
When the node performs a handover from the first access point to a second access point connected to the communication network, an identification number given to the node in advance from the second access point A second notification function to be notified,
A search function for searching the database for a network address stored in association with the identification number notified in the second notification function,
Computer-readable network management for causing a computer to implement a network address assignment function of assigning a network address found by the search function to a node handed over from the second access point to the second access point program.

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