JP3676347B2 - IP address management apparatus, IP address management method, and computer program - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an IP address management device and an IP address management method for assigning and managing an IP address to a wireless terminal device that performs IP packet communication via a wireless communication network, and the IP address management device using a computer. The present invention relates to a computer program for realizing.
[0002]
[Prior art]
Conventionally, when a wireless terminal device performs IP packet communication via a wireless communication network, an IP address is dynamically assigned to the wireless terminal device and managed. For example, in a wireless data communication system in which a wireless terminal device performs data communication using a PPP link established according to the PPP protocol, the PPP link is released due to the occurrence of a handover of the wireless terminal device, and the released PPP link is reopened. Sometimes. In such a case, the conventional IP address management method detects the occurrence of handover of the wireless terminal device, and re-assigns the same address as the IP address assigned before releasing the PPP link to the wireless terminal device by this detection. (For example, refer to Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-178462
[Problems to be solved by the invention]
However, since the above-described conventional IP address management method detects the occurrence of handover of the wireless terminal device, when the PPP link is released due to a factor other than handover, the IP assigned before the PPP link is released. There is no guarantee that the same address will be reassigned. For this reason, if a different IP address is assigned, after the PPP link is re-established, packet retransmission based on the IP address before release cannot be performed, resulting in a problem that data transfer efficiency deteriorates.
[0005]
The present invention has been made in consideration of such circumstances, and its purpose is not limited to handover, and a communication connection (for example, a PPP link) between a wireless terminal device and a wireless communication network is disconnected due to any factor. However, it is an object of the present invention to provide an IP address management device and an IP address management method capable of continuously assigning the same IP address as before disconnection to a wireless terminal device.
[0006]
It is another object of the present invention to provide an IP address management apparatus and an IP address management method that can effectively use an IP address.
[0007]
Another object of the present invention is to provide a computer program for realizing the IP address management device using a computer.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, an IP address management device according to claim 1 is a communication unit that transmits and receives data to and from a wireless communication network, and a wireless terminal that performs IP packet communication via the wireless communication network. IP address management means for allocating and responding to an IP address upon receipt of an IP address acquisition request from the apparatus and managing the assigned IP address, wherein the IP address management means includes the wireless communication network and the wireless terminal device. When receiving the termination notice of communication connection with, after a certain period of time from the reception time been made to release the IP address assigned to the wireless terminal device, all available in the wireless communication network For each IP address, there is an IP address management table that stores the terminal identification information of the assignment destination and the assigned flag indicating that it has been assigned. The terminal identification information corresponding to the IP address in the IP address management table is set when the IP address is assigned and the assigned flag is turned on, and the assignment corresponding to the IP address in the IP address management table is released when the IP address is released It is characterized by turning off the completed flag .
[0009]
According to the present invention, the IP address currently assigned to the wireless terminal device corresponding to the disconnection notification is secured while being assigned to the wireless terminal device for a certain period from the time when the communication connection disconnection notification is received. As a result, it is not limited to handover, even if the communication connection between the wireless terminal device and the wireless communication network is cut off due to any factor such as deterioration of radio wave conditions due to entry into a tunnel or building, etc. The same IP address as before can be continuously assigned to the wireless terminal device. Furthermore, after the elapse of a certain period from the reception of the disconnection notification, the IP address assigned to the wireless terminal device is released, so that the IP address can be used effectively.
[0010]
3. The IP address management device according to claim 2, wherein the IP address management means receives an IP address acquisition request from a wireless terminal device corresponding to the disconnection notification before the predetermined period has elapsed since the reception of the disconnection notification. Is received, the wireless terminal device responds with an already assigned IP address.
[0011]
According to the present invention, when an IP address acquisition request is received from a wireless terminal device corresponding to the disconnection notification within a certain period from the reception time of the communication connection disconnection notification, the already assigned IP address is returned as a response. Therefore, the IP address reassignment process becomes unnecessary, and the response time can be shortened.
[0012]
The IP address management method according to claim 3 is a first step of receiving an IP address acquisition request from a wireless terminal device that performs IP packet communication via a wireless communication network, and an IP address is acquired by the IP address acquisition request. A second process of allocating and responding, a third process of receiving a disconnection notification of the communication connection between the wireless communication network and the wireless terminal device, and after a lapse of a certain period from the reception time of the disconnection notification A fourth step of releasing an IP address assigned to the wireless terminal device, and an assignment destination terminal identification information and an assignment indicating that assignment has been made for all IP addresses usable in the wireless communication network A fifth process of managing an IP address management table storing a completed flag, and in the fifth process, when an IP address is allocated by the second process The terminal identification information corresponding to the IP address in the IP address management table is set, the assigned flag is turned on, and the assignment corresponding to the IP address in the IP address management table is performed when the IP address is released in the fourth process. It is characterized by turning off the completed flag .
[0013]
5. The IP address management method according to claim 4, wherein when the IP address acquisition request from the wireless terminal device corresponding to the disconnection notification is received before the elapse of the predetermined period from the reception of the disconnection notification, the wireless terminal The method further includes a step of responding to the IP address already assigned to the device.
[0014]
The computer program according to claim 5 assigns an IP address by a first process of receiving an IP address acquisition request from a wireless terminal device that performs IP packet communication via a wireless communication network, and the IP address acquisition request. Second processing that responds, third processing that receives a notification of disconnection of the communication connection between the wireless communication network and the wireless terminal device, and after the elapse of a certain period from the reception time of the disconnection notification, A fourth process for releasing an IP address assigned to a terminal device, and an assignment destination terminal identification information and an assigned flag indicating that assignment has been made for all IP addresses usable in the wireless communication network. Is a computer program that causes a computer to execute a fifth process for managing an IP address management table for storing When the IP address is assigned by the second process, the terminal identification information corresponding to the IP address in the IP address management table is set, the assigned flag is turned on, and the IP address is released by the fourth process. The assigned flag corresponding to the IP address in the IP address management table is turned off .
[0015]
In the computer program according to claim 6, when an IP address acquisition request from a wireless terminal device corresponding to the disconnection notification is received before the predetermined period has elapsed since the reception of the disconnection notification, the wireless terminal device In addition, the computer is further caused to execute a process of responding to an already assigned IP address.
As a result, the above-described IP address management apparatus can be realized using a computer.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration example of a wireless data communication system to which an IP address management server (IP address management device) according to an embodiment of the present invention is applied. The wireless data communication system shown in FIG. 1 uses a cellular phone network as a wireless communication network, and performs IP packet communication between a cellular phone as a wireless terminal device and a server.
[0017]
In FIG. 1, a mobile phone 1a communicates with a radio base station 2a. The mobile phone 1b communicates with the radio base station 2b. The radio base stations 2 a and 2 b are connected to the mobile phone network 3. The cellular phone network 3 is connected to the relay device 4. The relay device 4 is connected to both the mobile phone network 3 and the IP network 5. The relay device 4 mutually converts the protocols of the mobile phone network 3 and the IP network 5. By going through the relay device 4, the terminal on the mobile phone network 3 side and the server on the IP network 5 side can send and receive data to and from each other.
[0018]
The IP address management server 6 is connected to the IP network 5. The IP address management server 6 manages IP addresses that can be used in the wireless data communication system of FIG. The content server 7 is connected to the IP network 5. The content server 7 receives access from the terminal and provides various services such as downloading of content data.
[0019]
FIG. 2 is a block diagram showing the configuration of the IP address management server 6 shown in FIG. In FIG. 2, a communication unit 11 is connected to an IP network 5 and transmits / receives data to / from the relay device 4 by IP packet communication. The management unit 12 performs IP address management processing. The management unit 12 has a timer function. The IP address management table 13 stores management information for managing each IP address that can be used in the wireless data communication system of FIG. The IP address management table 13 is accessible from the management unit 12.
[0020]
FIG. 3 is a diagram showing a configuration example of the IP address management table 13 shown in FIG. In FIG. 3, the IP address management table 13 has assigned terminal identification information (terminal ID) and assignment indicating that all IP addresses usable in the wireless data communication system of FIG. Is set.
[0021]
In the example shown in FIG. 3, the IP address “AAA.BBB.CCC.001” has already been assigned to the mobile phone having the terminal ID “XXX1”. On the other hand, the IP address “AAA.BBB.CCC.010” is not assigned to any mobile phone.
[0022]
Next, with reference to FIG. 4 and FIG. 5, operations related to IP address management performed by the IP address management server 6 will be described. 4 and 5 are sequence charts showing the flow of IP address management processing in the wireless data communication system of FIG.
[0023]
First, in FIG. 4, when the user of the mobile phone 1 a performs an operation for accessing the content server 7, the mobile phone 1 a transmits an authentication request to the relay device 4 by PPP (Point-to-Point Protocol). This PPP authentication request corresponds to the IP address acquisition request, and includes the terminal ID of the mobile phone 1a (step S1). Next, the PPP authentication request is transmitted to the IP address management server 6 via the relay device 4 (step S2).
[0024]
Next, when receiving the authentication request via the communication unit 11, the management unit 12 of the IP address management server 6 searches the IP address management table 13 and already stores the terminal ID of the mobile phone 1 a included in the received authentication request. Check if there is an assigned IP address. As a result, when there is no assigned IP address in the terminal ID, one IP address (referred to as IP address A) is randomly selected from unassigned IP addresses whose assigned flag is off. . Then, the terminal ID of the mobile phone 1a is set in the terminal ID column corresponding to the selected IP address, and the assigned flag is turned on (step S3). Next, the management unit 12 includes the IP address A in the authentication response and transmits it to the relay device 4 (step S4).
[0025]
Next, the authentication response (IP address A) is transmitted to the mobile phone 1a via the relay device 4 (step S5). Next, when receiving the billing start notification from the relay device 4, the IP address management server 6 returns a response (steps S6 and S7). This billing start notification corresponds to the communication connection start notification of the mobile phone 1a. The cellular phone 1a performs IP packet communication with the content server 7 using its own IP address A (step S8).
[0026]
Next, for example, when the user of the mobile phone 1a enters the tunnel 6 of FIG. 1 and the communication connection (PPP link) between the mobile phone 1a and the mobile phone network 3 is thereby disconnected, the charging is terminated by the relay device 4 A notification is transmitted to the IP address management server 6 (step S9). This billing end notification corresponds to a communication disconnection notification of the cellular phone 1a and includes the terminal ID of the cellular phone 1a.
[0027]
Next, when the management unit 12 of the IP address management server 6 receives the billing end notification via the communication unit 11, it starts a timer (step S10). This timer period is set as a period corresponding to a temporary interruption of communication, and is, for example, 3 minutes. Then, a response to the billing end notification is transmitted (step S11).
[0028]
Next, the user of the mobile phone 1a exits from the tunnel 6, thereby enabling communication connection (PPP link) between the mobile phone 1a and the mobile phone network 3. Then, in order to access the content server 7, the mobile phone 1a transmits a PPP authentication request (IP address acquisition request) to the relay device 4 (step S12). This PPP authentication request is transmitted to the IP address management server 6 via the relay device 4 (step S13).
[0029]
Next, the management unit 12 of the IP address management server 6 receives the authentication request (IP address acquisition request) via the communication unit 11. At the time of reception, the timer started in step S10 has not expired. Next, the management unit 12 searches the IP address management table 13 to check whether there is an IP address already assigned to the terminal ID of the mobile phone 1a included in the received authentication request. As a result, since the terminal ID already has an assigned IP address A, the IP address A is included in the authentication response and transmitted to the relay device 4, and the timer started in step S10 is stopped (step S14). , S15).
[0030]
Next, the authentication response (IP address A) is transmitted to the mobile phone 1a via the relay device 4 (step S16). Next, when receiving the accounting start notification from the relay device 4, the IP address management server 6 returns a response (steps S17 and S18). The cellular phone 1a resumes IP packet communication with the content server 7 using the same IP address A as the IP address before disconnection of the communication connection (step S19). Thereby, the cellular phone 1a can perform packet retransmission with the content server 7 based on the IP address A before the communication connection is disconnected.
[0031]
Next, a case where the timer started in step S10 of FIG. 4 has expired will be described with reference to FIG.
In FIG. 5, when the timer started in step S10 expires (step S21), the management unit 12 of the IP address management server 6 in the IP address management table 13 includes the mobile phone 1a included in the billing end notification received in step S9. The assigned flag of the IP address A already assigned to the terminal ID is turned off (step S22). As a result, since the IP address A assigned to the mobile phone 1a is released, the IP address A can be reused and the IP address can be effectively used.
[0032]
As described above, according to the present embodiment, when a disconnection notification (billing end notification) of a communication connection (PPP link) between a wireless communication network (mobile phone network) and a wireless terminal device (mobile phone) is received, The IP address assigned to the wireless terminal device is released after a certain period of time has elapsed from the time of reception. As a result, the IP address currently assigned to the wireless terminal device corresponding to the disconnection notification is secured while being assigned to the wireless terminal device for a certain period from the time when the communication connection disconnection notification is received. As a result, the wireless terminal device and the wireless base station 2b are not limited to the handover from the wireless base station 2a to the wireless base station 2b in FIG. Even if the communication connection with the communication network is disconnected, the same IP address as before the disconnection can be continuously assigned to the wireless terminal device. Furthermore, after the elapse of a certain period from the reception of the disconnection notification, the IP address assigned to the wireless terminal device is released, so that the IP address can be used effectively.
[0033]
In addition, when an IP address acquisition request is received from the wireless terminal device corresponding to the disconnection notification within a certain period from the reception time of the communication connection disconnection notification, the already assigned IP address is responded. The IP address reassignment process becomes unnecessary, and the response time can be shortened.
[0034]
In the above-described embodiment, the cellular phone network has been described as an example of the wireless communication network, but the present invention can be similarly applied to other wireless communication networks such as a wireless LAN.
[0035]
In addition to the mobile phone described above, the wireless terminal device is configured by combining a mobile terminal called a PDA (Personal Digital Assistants) or a terminal such as a personal computer and a wireless communication device. It may be a thing.
[0036]
In the above-described embodiment, the communication unit 11 in FIG. 2 corresponds to a communication unit. The management unit 12 and the IP address management table 13 correspond to IP address management means.
[0037]
Also, a program for realizing each step performed by the IP address management server 6 shown in FIGS. 4 and 5 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system. The IP address management process may be performed by executing. Here, the “computer system” may include an OS and hardware such as peripheral devices.
Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.
The “computer-readable recording medium” refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, and a CD-ROM, and a storage device such as a hard disk built in the computer system.
[0038]
Further, the “computer-readable recording medium” refers to a volatile memory (RAM) in a computer system that becomes a server or a client when a program is transmitted via a network such as the Internet or a communication line such as a telephone line. In addition, those holding programs for a certain period of time are also included.
The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.
The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.
[0039]
The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design changes and the like within a scope not departing from the gist of the present invention.
[0040]
【The invention's effect】
As described above, according to the present invention, the IP address currently allocated to the wireless terminal device corresponding to the disconnection notification has been allocated to the wireless terminal device for a certain period from the reception time of the communication connection disconnection notification. Secured. As a result, it is not limited to handover, even if the communication connection between the wireless terminal device and the wireless communication network is cut off due to any factors such as deterioration of radio wave conditions due to entry into tunnels or buildings, etc. The same IP address as before can be continuously assigned to the wireless terminal device. Furthermore, after the elapse of a certain period from the reception of the disconnection notification, the IP address assigned to the wireless terminal device is released, so that the IP address can be used effectively.
[0041]
According to the second aspect of the present invention, when an IP address acquisition request from the wireless terminal device corresponding to the disconnection notification is received within a certain period from the time when the communication connection disconnection notification is received, Since the assigned IP address is responded, the reassignment process of the IP address becomes unnecessary, and the response time can be shortened.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration example of a wireless data communication system to which an IP address management device (IP address management server 6) according to an embodiment of the present invention is applied.
FIG. 2 is a block diagram showing a configuration of an IP address management server 6 shown in FIG.
3 is a diagram showing a configuration example of an IP address management table 13 shown in FIG. 2. FIG.
4 is a first sequence chart showing a flow of IP address management processing in the wireless data communication system of FIG. 1; FIG.
FIG. 5 is a second sequence chart showing a flow of IP address management processing in the wireless data communication system of FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1a, 1b ... Mobile phone, 2a, 2b ... Wireless base station, 3 ... Mobile phone network, 4 ... Relay device, 5 ... IP network, 6 ... IP address management server, 7 ... Content server, 11 ... Communication part, 12 ... management unit, 13 ... IP address management table

Claims (6)

A communication means for transmitting and receiving data to and from the wireless communication network;
IP address management means for allocating and responding to an IP address in response to reception of an IP address acquisition request from a wireless terminal device performing IP packet communication via the wireless communication network, and managing the assigned IP address;
The IP address management means
Upon receiving a notification of disconnection of the communication connection between the wireless communication network and the wireless terminal device, the IP address assigned to the wireless terminal device is released after a lapse of a predetermined period from the reception time point ,
An IP address management table for storing terminal identification information of an assignment destination and an assigned flag indicating that assignment has been made for all IP addresses usable in the wireless communication network;
Set the terminal identification information corresponding to the IP address in the IP address management table when assigning the IP address and turn on the assigned flag,
An IP address management apparatus , wherein an assigned flag corresponding to the IP address in the IP address management table is turned off when the IP address is released . When the IP address management means receives an IP address acquisition request from the wireless terminal device corresponding to the disconnection notification before the elapse of the predetermined period from the reception time of the disconnection notification, the IP address management means is already assigned to the wireless terminal device The IP address management apparatus according to claim 1, wherein the IP address management apparatus responds with a completed IP address. A first process of receiving an IP address acquisition request from a wireless terminal that performs IP packet communication via a wireless communication network;
A second process of responding by assigning an IP address in response to the IP address acquisition request;
A third step of receiving a notification of disconnection of a communication connection between the wireless communication network and the wireless terminal device;
A fourth process of releasing an IP address assigned to the wireless terminal device after a lapse of a certain period from the reception time of the disconnection notification;
A fifth step of managing an IP address management table storing terminal identification information of an assignment destination and an assigned flag indicating that assignment has been made for all IP addresses that can be used in the wireless communication network; Including
In the fifth step,
When assigning an IP address in the second step, set terminal identification information corresponding to the IP address in the IP address management table and turn on an assigned flag;
An IP address management method , wherein an assigned flag corresponding to the IP address in the IP address management table is turned off when the IP address is released in the fourth process . If an IP address acquisition request is received from the wireless terminal device corresponding to the disconnection notification before the elapse of the predetermined period from the reception time of the disconnection notification, an already assigned IP address is responded to the wireless terminal device The IP address management method according to claim 3, further comprising: a process. A first process of receiving an IP address acquisition request from a wireless terminal device that performs IP packet communication via a wireless communication network;
A second process of responding by assigning an IP address in response to the IP address acquisition request;
A third process of receiving a communication connection disconnection notification between the wireless communication network and the wireless terminal device;
A fourth process of releasing an IP address assigned to the wireless terminal device after a lapse of a certain period from the reception time of the disconnection notification;
A fifth process for managing an IP address management table that stores terminal identification information of an assignment destination and an assigned flag indicating that assignment has been made for all IP addresses that can be used in the wireless communication network; A computer program to be executed by a computer;
In the fifth process,
When assigning an IP address in the second process, set terminal identification information corresponding to the IP address in the IP address management table and turn on an assigned flag;
A computer program that turns off an assigned flag corresponding to an IP address in the IP address management table when an IP address is released by the fourth process . If an IP address acquisition request is received from the wireless terminal device corresponding to the disconnection notification before the elapse of the predetermined period from the reception time of the disconnection notification, an already assigned IP address is responded to the wireless terminal device The computer program according to claim 5, further causing the computer to execute processing.

Images