JP2004193643A - Ip address automatic assignment method / program, and terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of quickly and reliably automatically assigning IP addresses while using a method by an ARP request. <P>SOLUTION: An ARP request containing a temporary IP address is sent to a plurality of terminals on a TCP/IP network (203), and the temporary IP address is set as an IP address (207), if no ARP answer is received within a specified time (206). If the ARP answer is received (206), an ICMP-ECHO request is sent to the plurality of terminals on the TCP/IP network (209), unlike repeating the above steps after changing the temporary IP address, ICMP-ECHO answers containing their IP addresses are received from the plurality of terminals (213) to automatically generate IP addresses not conflicting with the IP addresses of the plurality of terminals (214), and they are set as IP addresses (207). The temporary IP address may use an IP address used when the terminal is connected to the network. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for automatically assigning an IP address of a terminal.
[0002]
[Prior art]
In a TCP / IP network, when a terminal is connected on the network, it is necessary to assign an IP address for uniquely identifying the terminal to each terminal.
[0003]
In the related art, since an IP address is fixedly assigned to all terminals connected to a network, it is necessary for a network administrator to manage an IP address for each terminal. In this case, every time the user of the portable terminal connects the terminal to the network, it is necessary to confirm the available IP address with the network administrator, and to set the IP address in the terminal each time.
[0004]
However, in this method, there are many setting items for the administrator and the terminal user, and there is a possibility that communication may be disabled due to a setting error.
[0005]
Therefore, a method (DHCP) for inquiring a server about an IP address that can be used by a terminal when the terminal is installed on a network has been proposed.
[0006]
If there is no DHCP server on the network, an ARP request packet including a temporary IP address is transmitted to another terminal on the network, and an ARP response is returned from the other terminal within a predetermined time. In such a case, a technique has been proposed in which it is determined that the temporary IP address is not used by another terminal, and the IP address is set as an official IP address (for example, see Patent Documents 1 to 3).
[0007]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2002-237816 [Patent Document 2]
Japanese Patent Application Laid-Open No. 9-200247 [Patent Document 3]
JP-A-8-223169
[Problems to be solved by the invention]
Certainly, this method using the ARP request has an advantage that an IP address can be easily set without requiring a server for setting the IP address.
[0009]
However, when the ARP response is received, the temporary IP address is being used by another terminal. Therefore, the same process is repeated until the ARP response is no longer received, replacing the temporary IP address with another one. Therefore, depending on the situation, it may take too long to set the IP address.
[0010]
Therefore, an object of the present invention is to provide a method for quickly and reliably automatically assigning an IP address while using a method based on an ARP request.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, first, a connecting terminal transmits an ARP request including a temporary IP address to a plurality of terminals on a TCP / IP network, and does not receive an ARP response within a predetermined time. At times, a temporary IP address is set as an IP address. When the ARP response is received, instead of changing the temporary IP address and repeating the above processing, an ICMP-ECHO request is transmitted to a plurality of terminals on the TCP / IP network, and the IP addresses are transmitted from the plurality of terminals. Upon receiving the included ICMP-ECHO response, an IP address that does not conflict with the IP addresses of a plurality of terminals is automatically generated and set as an IP address.
[0012]
Further, as the temporary IP address, the IP address when the terminal previously connected to the network may be used. In a portable terminal particularly assumed in the present invention, if not much time has passed since the last connection, there is a high possibility that the previously set IP address has not been used by another terminal. This is because there is a high possibility that an IP address can be quickly set only by processing based on an ARP request.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0014]
Referring to FIG. 1, there is shown a state in which a terminal 1 according to an embodiment of the present invention is connected to a TCP / IP network to which many terminals are already connected. Each of the already connected terminals has an IP address, and the terminal 1 has a function of generating and setting an IP address that does not conflict with these IP addresses.
[0015]
Next, the configuration of the terminal 1 according to one embodiment of the present invention will be described with reference to FIG.
[0016]
The terminal 1 includes an address generation information storage unit 11, a temporary IP address generation unit 12, an ARP request transmission unit 13, an ARP response reception unit 14, an address conflict determination unit 15, an ICMP-ECHO request transmission unit 16, It includes an ICMP-ECHO response receiving unit 17, an IP address generating unit 18, an IP address setting unit 19, and a response terminal registration table 20.
[0017]
The address generation information storage unit 11 connects the terminal 1 to a TCP / IP network, and stores a network address and a subnet mask for generating an IP address necessary for performing TCP / IP communication. Further, it stores the IP address when the terminal 1 last connected to the TCP / IP network.
[0018]
The temporary IP address generation unit 12 generates a temporary IP address based on the network address and the subnet mask stored in the address generation information storage unit 11.
[0019]
The ARP request transmission unit 13 determines that the terminal having the previous IP address stored in the address generation information storage unit 11 or the temporary IP address generated by the temporary IP address generation unit 12 already exists on the TCP / IP network. An ARP request packet for inquiring is generated and transmitted.
[0020]
The ARP response receiving unit 14 receives an ARP response packet from another terminal on the TCP / IP network.
[0021]
The address conflict determination unit 15 monitors the reception of the ARP response, and when receiving the ARP response, determines that the previous IP address or the temporary IP address has already been used by another terminal, and within a predetermined time period. When the ARP response is not received, it is determined that the previous IP address or the temporary IP address is not used by another terminal, and the IP address setting unit 19 is requested to set the IP address or the temporary IP address as the IP address.
[0022]
When the address conflict determination unit 15 determines that the previous IP address or the temporary IP address has already been used, the ICMP-ECHO request transmission unit 16 inquires of an IP address used by another terminal on the TCP / IP network. To send an ICMP-ECHO request packet.
[0023]
The ICMP-ECHO response receiving unit 17 receives an ICMP-ECHO response including the IP address of the terminal from another terminal.
[0024]
The response terminal registration table 20 stores the IP address of another terminal on the network included in the ICMP-ECHO response received by the ICMP-ECHO response receiving unit 17.
[0025]
The IP address generation unit 18 automatically generates an IP address that does not conflict with the IP addresses of other terminals on the TCP / IP network registered in the response terminal registration table 20.
[0026]
The IP address setting unit 19 stores the last IP address or temporary IP address determined by the address conflict determination unit 15 not being used by another terminal, or the IP address automatically generated by the IP address generation unit 18 in the terminal. And saves the set IP address in the address generation information storage unit 11 for the next time the terminal is reconnected to the TCP / IP network.
[0027]
Next, the operation of the terminal 1 will be described with reference to FIG.
[0028]
In step 201, an IP address assigned when the terminal 1 previously connected to the TCP / IP network is acquired from the address generation information storage unit 11. If there is no previously assigned IP address, in step 202, the temporary IP address generation unit 12 randomly generates a temporary IP address.
[0029]
In step 203, the ARP request transmitting unit 13 generates an ARP request packet including these IP addresses, and transmits the generated ARP request packet to another terminal on the TCP / IP network.
[0030]
At step 204, an ARP response wait timer is set, and at step 205, an ARP response or timeout event is waited.
[0031]
In step 206, an event is determined. If there is no ARP response for a certain period of time and a timeout event is received, it is determined that there is no conflict even if this IP address is used, and this IP address is set in the terminal 1 in step 207. Further, in step 208, it is stored in the address generation information storage unit 11 as an initial IP address for the next connection to the TCP / IP network.
[0032]
If an ARP response event is received in step 206, another terminal on the TCP / IP network has already used this IP address. In step 209, an ICMP-ECHO request packet (broadcast transmission) is generated and transmitted.
[0033]
In step 210, an ICMP-ECHO response waiting timer is set, and in step 211, an ICMP-ECHO response or timeout event is waited.
[0034]
In step 212, an event is determined. If an ICMP-ECHO response event is received, the IP address of the response source terminal included in the ICMP-ECHO response is registered in the response terminal registration table 20 in step 213. Thereafter, the process returns to step 211 to wait for a response from another terminal on the TCP / IP network, and repeats this process until a time-out event is received in step 212.
[0035]
When a timeout event is received in step 211, the process proceeds to step 214. Since the source IP addresses included in all ICMP-ECHO response packets received before the timeout are used by other terminals already existing on the TCP / IP network, IP addresses that do not conflict with these IP addresses Is automatically generated.
[0036]
Then, in step 207, this IP address is set in the terminal 1, and in step 208, it is stored in the address generation information storage unit 11 as an initial IP address for the next connection to the TCP / IP network.
[0037]
【The invention's effect】
As described above, according to the present invention, an IP address of another terminal is obtained by an ICMP-ECHO request and an IP address that does not conflict is set, using an ARP request method. Can be set.
[0038]
In addition, by using the IP address of the terminal when the terminal was previously connected to the network as the temporary IP address, especially when the portable terminal has not been connected for a long time since the previous connection, the previously set IP address becomes different from the previously set IP address. There is a high possibility that the terminal is not used by the terminal, and in this case, the IP address can be quickly set only by the processing according to the ARP request.
[0039]
In addition, since IP address management for each terminal connected to the TCP / IP network is not required, when connecting a portable terminal that is not always connected to the network, it is necessary to check and set a free IP address for connection. It becomes unnecessary.
[0040]
In addition, since the IP address is generated on the terminal side, an address management server becomes unnecessary, and the cost, the burden on the administrator, and the burden on the terminal user in the setting work can be reduced.
[0041]
Further, by reducing the work of the administrator and the user, it is possible to reduce a network failure caused by a setting error.
[Brief description of the drawings]
FIG. 1 is a diagram showing a network system to which a terminal 1 of the present invention is applied.
FIG. 2 is a diagram showing a configuration of a terminal 1.
FIG. 3 is a diagram showing an operation of the terminal 1.
[Explanation of symbols]
1 Terminal 11 Address generation information storage unit 12 Temporary IP address generation unit 13 ARP request transmission unit 14 ARP response reception unit 15 Address conflict determination unit 16 ICMP-ECHO request transmission unit 17 ICMP-ECHO response reception unit 18 Main IP address generation unit 19 IP address setting unit 20 Response terminal registration table 201-214 Step

Claims (5)

When a new terminal is connected to a TCP / IP network to which a plurality of terminals are already connected, a method for automatically allocating an IP address without conflicting with the IP addresses of the plurality of terminals,
The connecting terminal transmits an ARP request including a temporary IP address to the plurality of terminals on the TCP / IP network, and connects the temporary IP address when the terminal does not receive an ARP response within a predetermined time. A first step of setting as a terminal IP address;
Upon receiving the ARP response in the first step, the connecting terminal sends an ICMP-ECHO request to the plurality of terminals on the TCP / IP network, and the ICMP-ECHO including an IP address from the plurality of terminals. Receiving a response, automatically generating an IP address that does not conflict with the IP addresses of the plurality of terminals, and setting the IP address as the IP address of the connecting terminal. The method according to claim 1, wherein the temporary IP address is an IP address when the connecting terminal was previously connected to the TCP / IP network. In a terminal device connectable to a TCP / IP network,
A first means for transmitting an ARP request including a temporary IP address to a plurality of terminals on the TCP / IP network and setting the temporary IP address as an IP address when an ARP response is not received within a predetermined time When,
When receiving the ARP response, the ICMP-ECHO request is transmitted to the plurality of terminals on the TCP / IP network, and the ICMP-ECHO response including the IP address is received from the plurality of terminals. A terminal device comprising second means for generating and setting an IP address that does not conflict with an IP address. 4. The terminal device according to claim 3, wherein the first unit uses, as the temporary IP address, an IP address that has been previously connected to the TCP / IP network. 5. 3. An automatic IP address assignment program for causing a terminal connected to a TCP / IP network to execute the method according to claim 1 or 2.

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