JP2003143172A - Network connection device and method for allocating ip address of network connection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a user to continue communication in another LAN as it is without having the user be conscious of an IP address even if moving a communication terminal in a communication network to the other LAN and using it. SOLUTION: A network connection device 1 having a LAN using an Internet protocol, one or more communication terminals and a plurality of ports for connecting the communication terminals to the LAN, is provided with a LAN side address set decision means for deciding whether the IP address allocation system of the LAN is static allocation or dynamic allocation, a communication terminal address set decision means for deciding whether the IP address allocation system of each connected communication terminal is static allocation or dynamic allocation, and an allocation means for performing address allocation of the LAN side and/or the communication terminal side in accordance with the combination of the LAN side address set decision results and the communication terminal address set decision results.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network connecting device and an allocating method for a local area network (LAN), and more particularly to a network connecting device and an allocating method for connecting various communication terminals without error.

[0002]

2. Description of the Related Art An IP (Internet Protocol) address consists of a global address that can be recognized all over the world and a private address that defines a communication terminal within the range of a company LAN. The global address is centrally managed by the registrar, but the private address is given as necessary depending on the scale of the LAN, expansion, etc. In the present case and the specification, a private address will be handled, and this will be referred to as an IP address.

Dynamic allocation and static allocation are available as methods for allocating IP addresses to communication terminals connected to a LAN. Dynamic allocation uses a DHCP (abbreviation of Dynamic Host Configuration Protocol) server and automatically assigns an IP address to the communication terminal by DHCP only when the communication terminal uses a LAN. is there. Further, when Internet communication is performed using the provider, the provider incorporates DHCP into its own server and gives an IP address to the user. On the other hand, in static allocation, a user who uses a communication terminal sets an IP address by himself. Most cases do not have DHCP, but there are also examples in which static allocation is selected by the user's own will even with DHCP.

Since the communication terminal is a notebook type or a card type, it is often the case that the user carries it to another place and uses another LAN.
For example, this corresponds to an example of changing the work place or changing the arrangement. This is possible not only for notebook type and desktop type.

[0005]

Problems to be Solved by the Invention From one LAN to another L
When the communication terminal is moved to the AN, there is a problem of handling the IP address. The user has to check whether the IP address on the LAN before moving can be used as it is, or whether a new IP address needs to be set again. Moreover, in communication, an error in the IP address occurs, causing communication failure.

[0006] An object of the present invention is to provide a network connection device which enables communication on another LAN without the user being aware of the IP address even when the communication terminal is moved to another LAN for use. Is provided. Still another object of the present invention is to provide a network connection device and an IP address allocation method for the same, which can eliminate an IP address error and eliminate a communication failure due to an IP address error.

[0007]

According to the present invention, there is provided a LAN using an Internet protocol, one or more communication terminals, and a network connection device having a plurality of ports for connecting the communication terminals to the LAN. LAN that determines whether the IP address allocation method of the device is static allocation or dynamic allocation
Side address setting judging means, communication terminal address setting judging means for judging whether the IP address allocation method of each of the connected communication terminals is static allocation or dynamic allocation, LAN side address setting judgment result and communication terminal address setting Disclosed is a network connection device comprising: an allocation unit that allocates an address on the LAN side and / or a communication terminal side according to a combination of determination results.

Further, according to the present invention, when the LAN side is statically assigned and the communication terminal is statically set, the assigning means statically assigns a static address set in the communication terminal to a port in advance for connection. LAN shall be converted to address
When the side is dynamically assigned and the communication terminal is statically set, a dynamic address is assigned to the LAN side port, the static address set in the communication terminal is converted to the address assigned to the LAN side port, and the LAN side If the communication terminal side is statically assigned and the communication terminal side is dynamically set, the static address previously assigned by the administrator to the LAN side port is assigned to the communication terminal, and if the LAN side is dynamically assigned and the communication terminal side is dynamically set, communication is performed. A network connection device is disclosed in which, in response to an address allocation request from a terminal to the network connection device, an address allocation request is made to the LAN side, and a dynamic address allocated from the LAN side is allocated to a communication terminal.

The present invention is a method for assigning an IP address in a network connection device having a LAN using an Internet protocol, one or more communication terminals, and a plurality of ports for connecting the communication terminals and the LAN. LA
The IP address assignment method of N is determined whether it is static assignment or dynamic assignment, and whether the IP address assignment method of each connected communication terminal is static assignment or dynamic assignment, and the above LAN side address setting determination result Disclosed is an IP address allocating method for a network connection device, characterized in that the LAN side and / or the communication terminal side are allocated in accordance with the combination of the communication terminal address setting determination result.

In the above-mentioned address allocation of the present invention, when the LAN side is statically allocated and the communication terminal is statically set, the static address set in the communication terminal is previously allocated to the port for connection. Shall be converted to LA
If N side is dynamically assigned and communication terminal is statically set, LAN
When a dynamic address is assigned to the port on the side, the static address set in the communication terminal is converted to the address assigned to the port on the LAN side, and the LAN side is statically assigned and the communication terminal side is dynamically set, the LAN side Assign a static address that has been assigned in advance by the administrator to the port of the
When the communication side is dynamically assigned and the communication terminal side is dynamically set, in response to the address assignment request from the communication terminal to the network connection device, the LAN side issues an address assignment request and the dynamic address assigned from the LAN side is assigned to the communication terminal. A method for assigning an IP address of a network connection device to be attached is disclosed.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The concept of the present invention will be described first.
To set the IP address of the LAN, it is necessary to consider the network environment and communication terminal settings. An explanatory diagram thereof is shown in FIG. Here, the network environment is assumed to be dynamic when a DHCP server exists in each segment and static if it does not exist. The communication terminal setting is dynamic when the DHCP server exists when setting the IP address of the user terminal,
If it does not exist, it is assumed to be static. Specifically, when setting the IP address of the user terminal, the communication terminal setting is dynamically set to automatically acquire the address from the DHCP server, and the address assigned by the administrator (or user) is used. The setting method is static. FIG. 2 is a diagram for explaining communication enabled / disabled by an IP address under the network environment and communication terminal settings. The combination between the network environment and the communication terminal setting includes dynamic-dynamic as combination 1, static-dynamic as combination 2, dynamic-static as combination 3, and static as combination 4. There are four combinations of static-static. The combination 1 can communicate from the communication terminal to the network (that is, another communication terminal) when the communication terminal is moved to another LAN. In the case of the combination 2, when it is moved to another, the communication terminal cannot communicate with the network (that is, another communication terminal). When the combination 3 is moved to another, the communication is possible only when the IP address that matches the dynamic IP address system is statically set in the communication terminal. The combination 4 cannot communicate when the IP address set in the communication terminal is set incorrectly, and can communicate if the IP address is set without error.

One feature of the present invention is that communication is enabled even when communication is not possible in the combinations 2, 3, and 4. Hereinafter, the combinations 1 to 4 will be described in more detail. (1), Combination 1 ... When the network is a dynamic IP address and the communication terminal settings are also dynamic. FIG. 3 shows such a situation. The common server 100, the DHCP servers 101 and 104, and the segment 102 (Subne
t: 30, 30, 30, 255), 103 (Subne
t: 20, 20, 20, 255), 105 (Subne
t: 10, 10, 10, 10, 255), hub 106, 10
7, a terminal (personal computer) 108 and a router 109. Now, assuming that the terminal 108 is connected to the hub 106 connected to the segment 103, if this terminal is connected to the hub 107 connected to the segment 105 with the terminal settings kept unchanged, DHCP connected to the segment 105 will be obtained. New IP from server 104
An address is set and given. Thus, the terminal 108 after the location change can communicate with the network. In this case, communication with the network is possible even if the hub 107 has the same configuration as the hub 106 having the conventional configuration.
A new function can be achieved by configuring the hub 107 as described later in this embodiment (referred to as a product of the present invention).
Here, the hub 107 corresponds to the connection device 1 of FIG. 1 described later. However, because of the one-to-one relationship with the communication terminals, FIG. 3 and FIG. 1 show n communication terminals 7a to 7 for the connection device 1.
The feature is that it is connected to c.

This will be described with reference to FIGS. FIG. 4 shows a function example similar to the conventional one, and FIG. 5 shows a new function example. The hub 107 has an assigned IP address section 107A and a terminal flag section 107.
B, and switches 107C and 107D. FIG. 4 shows an example of a function similar to that of the conventional hub 106, in which an IP address is acquired from the DHCP server 104 by the route L ₁ indicated by an arrow, and communication with the network is performed by this route L ₁ . This is an example of obtaining an IP address from the DHCP server 104 by making the switch function as a repeater like the conventional hub 106. FIG. 5 shows the I assigned to the DHCP request from the terminal 108 in the same manner as the DHCP server.
In this example, the arrow route L ₂ enables communication to another terminal by returning the P address. Further, when the IP address is assigned by the terminal flag of the terminal flag unit 107B, the switch 107D is controlled to be turned ON on the left side of the drawing to enable direct communication to another terminal.

(2), combination 2 ... The network is static I
When the communication terminal setting is dynamic with P address. An example thereof is shown in FIGS. This is an example in which the segment 105 side does not have a DHCP server. The terminal 108 connected to the segment 103 in FIG.
When connecting to 05, since the DHCP server does not exist in the segment 105, the terminal 108 cannot acquire the IP address and cannot communicate with other terminals. Aruni hub 107
Communication becomes possible by using. That is, as shown in FIG. 7, since the terminal 108 is dynamically set, the terminal 108 uses the assigned IP address of the assigned IP address section 107A in response to the DHCP request from the terminal 108 in the same manner as the DHCP server to communicate. Is possible. Further, when the IP address is assigned by the terminal flag, the switch 107D is controlled to be turned on on the left side of the drawing to enable direct communication with another terminal.

(3) Combination 3 ... The network is dynamic I
When the communication terminal setting is static with P address. 8 and 9 show the examples. In FIG. 8, the DHCP server 101 is not connected to the segment 103. When the terminal 108 connected to the segment 103 is connected to the segment 105, it cannot communicate with other terminals because the network address is different. However, if the IP address is set again and there is no duplication of IP addresses, communication is possible.

FIG. 9 shows an example in which the hub 107 is installed. In FIG. 9, since the terminal 108 is statically set, the hub 107 detects the IP address when the terminal 108 is started up, converts the address into the assigned IP address, and communication becomes possible. In this case, the switch 107D control based on the terminal flag is not performed (the switch is kept ON on the right side of the figure), and the communication to other terminals always goes through the address conversion process.

(4), combination 4 ... The network is static I
When the P address and communication terminal settings are static. An example thereof is shown in FIGS. FIG. 10 shows an example in which neither the segment 103 nor the segment 105 has a DHCP server. If the terminal 108 connected to the segment 103 is connected to the segment 105 and the IP address that can be used in the segment 105 is set again, network connection is possible even in the conventional case. However, if the IP address is set incorrectly, communication will not be possible.

FIG. 11 shows a case where the hub 107 is changed. Since the hub 107 is provided, the IP address assigned to the hub 107 can be converted into an IP address for communication. That is, since the terminal 108 is statically set, the hub 107 detects the IP address when the terminal 108 is activated, and converts the wrongly set IP address into the assigned IP address to enable communication. In this case, the switch control by the terminal flag is not performed, and the communication to other terminals always goes through the address conversion process.

FIG. 1 shows the content structure of a network connection device 1 which is an embodiment of the present invention. 2 to 11 described above
In the above examples, the connection device 1
Is for collectively controlling connection to a plurality of terminals 7a, 7b, 7c. The connection device 1 has a memory 2 including a default setting unit 2a, a storage unit 2b for storing an address state (network flag) on the network side, and an address conversion table 2c for storing a table for automatically converting an IP address, an address of each communication terminal. Identification flag units 3a, 3b, 3c in the set state, external connection ports 4a to 4d, straight to other network connection devices /
Mode changeover switch 5d for cross connection, NAT
It has switches 5a to 5c for canceling the / DHCP function and a processing function 6 for registering / deleting an address translation table and setting a flag. In response to connection requests from the communication terminals 7a to 7c having different IP addresses of the ports 4a to 4c to the server, the NAT (Ne
twork address translation) and DHCP processing to enable communication. The IP addresses of the terminals 7b and 7c are (20, 20, 20, 100), (200, 10,
2, 50), and the addresses of switches 5a-5c are
(200, 10, 2, 10), (200, 10, 2, 1)
1) and (200, 10, 2, 12). The communication terminal 7c is connected via the hub 10.

FIG. 12 shows an example of the external appearance of the network connection device 1 of the present invention. The port 4d has a mode changeover switch 5d for performing straight / cross conversion for cascade connection with another network connection device. The other ports 4a to 4c have switches 5a to 5c for canceling the NAT / DHCP function. These switches 5a-5c are
When the DHCP settings and IP address are fixed like the communication terminals 7a to 7c, go to "Conversion", when performing cascade connection with a network connection device such as a hub, or when NAT or D
If you do not need the HCP function and want to cancel the function, switch to "Cancel".

FIG. 13 shows a connection configuration example of a network system to which the network connection apparatus according to the embodiment of the present invention is applied. In this network system, communication terminals 7a to 7c are connected to the respective ports 4a to 4d of the network connection device 1 according to the present invention, and the segment 13 (2
22, 100, 100, 1), 14 connecting local routers 16 (200, 10, 2, 1), communication terminal 7
server 12 (222, 100, 10) shared by a to 7c
0, 50), 15 (200, 10, 2, 30). TCP / IP is used as the communication protocol of this network system, and each communication terminal 7a-7
It is assumed that the IP address is statically or dynamically assigned to c. For example, if the terminal 7b is (20, 20, 2
0, 100) and terminal 7c is (200, 10, 2, 40)
Is.

FIG. 14 shows a flow for diagnosing and registering the address setting (dynamic or static) used in the network. This diagnosis / registration is performed every time the power of the connection device 1 is turned on. The default value of this device is determined by the administrator. After the power is turned on, the following processing is performed to diagnose whether the address is static or dynamic. In case of static address setting (default), read default setting of diagnostic / setting network flag
(F ₁ ), confirm that the network flag is “0”
(F ₂ ) and make a DHCP request (F ₃ ) to the segment side,
On the condition that there is no response to this (F ₄ ), “1” is registered in the section 2b in the network flag, and the process ends. In case of static address setting (administrator setting) read default setting of diagnostic network flag
(F ₁ ), confirm that the network flag is not “0”
(F ₂ ) and the process ends. Read default settings for diagnostic network flags for dynamic addressing
(F ₁ ), on the condition that the network flag is “0” (F ₂ ), a DHCP IP lease request (F ₃ ) is performed, and a response to this request is waited for (F ₄ ), and the process ends.

The above-mentioned NAT mechanism will be described with reference to FIG. In FIG. 17, the NAT means 200 is provided between the terminal 7 and the servers 20A and 20B. This NAT means 200
Functions as a relaying means between the global network and the local network, and is used for connecting an IP address (private address) uniquely assigned within a company to the global network such as the Internet. This is a function of converting the original packet 1 private address (10, 1, 1, 2) into the packet 2 of the global address (210, 156, 72, 1). The destination address is the IP address (210, 156, 72, 3) of the server 20A. An example of such conversion is shown in FIG. There are methods to statically assign private addresses and global addresses, and methods to dynamically assign them. It is realized with dedicated software and hardware, but recently, some routers support it as an additional function. Similar to the proxy service, it can prevent intrusion from the outside and leakage of address status in the private network to the Internet.

The above-mentioned DHCP mechanism will be described with reference to FIG. (1) First, the communication terminal 7, which is a client, sends an IP lease request (DHCP Discover). This is the IP
This is done by making a broadcast requesting addressing information. (2), the DHCP server 20 provides the client communication terminal 7 with an IP lease (DHCP Offer). This is done by broadcasting the IP addressing information that the server 20 can provide. (3) The client communication terminal 7 makes an IP lease selection (DHCP Request). This is performed by the client communication terminal 7 selecting the IP addressing information from the received provided information and broadcasting the lease request. (4) The server 20 performs an IP lease (DHCP Ack). This is done by the server 20 requested for lease broadcasting the reception confirmation.

FIG. 15 shows the contents of default settings in the memory 2 set by the administrator. Items include a network flag for determining whether the network address set in FIG. 4 is dynamically set or a static address, and an item for storing a static address assigned to each of the ports 4a to 4c. is there. This allows the administrator to set flags and assign static addresses to specific ports.

FIG. 16 is a diagram showing a network flag of the memory 2. The network flag indicates the address state (static or dynamic) of the network to which this device is connected. When the network flag is "0", the address is dynamically assigned. In the case of "1", it indicates a state in which an address is statically set. It may be determined by default setting.

FIG. 19 shows an example of an IP address conversion table in the memory 2. The fixed IP address (for example, 20, 20, 20, 100) of the communication terminal 7b is detected and registered in association with the converted IP address assigned to the port 4b. If the communication terminal is set to DHCP, the address is not translated, so the address is not registered in this table, and the same applies when the NAT / DHCP function is canceled. Ports 4a and 4c are examples.

FIG. 20 shows the correspondence between the terminal flag states in the terminal flag units 3a to 3c and the IP address setting state which is the terminal environment of the communication terminal. The terminal flag indicates the state / setting environment of the communication terminal. The connection device 1 receives the setting information sent when the power of the communication terminal is turned on, and the processing means determines the state and registers it as a terminal flag. The flags and states will be described below. “00”: Indicates that the communication terminal is not connected to the port or the NAT / DHCP function of the network connection device is released. “01”: Indicates that the communication terminal has DHCP settings and has assigned the IP address registered in the port. "10": Indicates that the communication terminal has a fixed IP address setting and is using the NAT function of the network connection device.

The state of the network flag in FIG. 16 and FIG.
A holding period is provided in the address conversion table 9 and the terminal flag in FIG. The state of the network flag in FIG. 16 is maintained from the time the power of the present apparatus is turned on until the power is turned off, as shown in the transition diagram of FIG. Also, FIG.
In FIGS. 9 and 20, as shown in the transition diagram of FIG. 22, it is assumed that the link with the connection device is established from the power-on of the communication terminal to the power-off. In this way, when the power of the communication terminal is cut off or the link between the ports is broken, both the table and the memory are cleared. As a method, for example, when the link between the communication terminal and the port is established, power is supplied to the memory to make it non-volatile. In addition, the memory volatilizes when the power is cut or the link is cut. As a mechanism for volatilizing the memory, when the terminal flag of FIG. 20 transits to “00”,
Delete the address translation table corresponding to the port.

23 and 24 show an address conversion flow when a communication terminal accesses a server. -1.1 When the communication terminal and network addresses are static addresses, and the operation at power-on is as follows. When the communication terminal is powered on, the connection device receives an access request from the communication terminal. At this timing, the network flag (F ₁ ) and the terminal flag (F ₂ ) are read. In this case check that network flag is not "0" (F ₃₎ is performed, confirmation that the terminal flag is "00" (F ₄₎ is performed. Next received data is DHCP
It is confirmed (F ₅ ) that it is not the broadcast (IP lease request), and the source IP is detected from the IP packet.
(F ₈ ) and a conversion table is created (F ₉ ). Further, setting a terminal flag to "10" _{(F 10),} and address translation _{(F 11)}
Allows access.

-1.2 when the communication terminal is a static address and the network address is a dynamic address,
Moreover, the operation when the power is turned on is as follows. When the communication terminal is powered on, the connecting device receives an access request.
At this timing, the network flag (F ₁ ) and the terminal flag (F ₂ ) are read, confirmation that the network flag is “0” (F ₃ ), confirmation that the terminal flag is “00”
(F _{1 2} ) is performed. Next, it is confirmed (F ₁₄ ) that the received data is not DHCP broadcast,
From the IP packet to the static address and physical (MA
C) The address is detected (F ₁₅ ) and the MAC address is registered in the spare buffer. The DHCP server on the network side is processed (F ₁₈ ), and the static address on the network side is registered in the address conversion table (F ₁₉ ). Also, it sets the terminal flag to "10" (F _20), and address translation (F
₂₁ ) allows access.

-2.1 Addition of communication terminal and network
The operation when the address is a static address is as follows. Communication end
Network flag (F₁)When
Terminal flag (F _Two) Is read and the network flag is "0"
Confirm that it is not (F_Three) And the terminal flag is not "00"
Confirm that (F_Four) Do. Also, if the terminal flag is not "01"
If (F_Thirteen), Address conversion (F₁₁) Access by
Is possible. −2.2 The communication terminal has a static address and
The operation when the address is a dynamic address is as follows. Communication
The network flag (F
₁) And terminal flag (F _Two), Read the network flag
Confirm that is "0" (F_Thirteen), And the terminal flag is "0.
Confirm that it is not "0" (F₁₂) Do. Also, the terminal flag
Is "01" (F_Thirteen) It is possible to access as it is
It

-1.1 When the addresses of the communication terminal and the network are dynamic addresses (when the power is turned on), the operation is as follows. When the communication terminal is powered on, this device receives an access request. Network flag (F ₁ ) at this timing
And the terminal flag (F ₂ ) are read, it is confirmed that the network flag is “0” (F ₃ ) and that the terminal flag is “00” (F ₁₂ ). Next received data is D
If it is the broadcast of HCP (F ₁₄ ), the process is performed with the DHCP server on the network side (F ₂₂ ). Also, it sets the terminal flag to "01" and (F _23), thereby enabling access.

-1.2 When the communication terminal is a dynamic address and the network address is a static address (when the power is turned on), the operation is as follows. When the communication terminal is powered on, this device receives an access request. At this timing, the network flag (F ₁ ) and the terminal flag (F ₂ ) are read, it is confirmed that the network flag is not “0” (F ₃ ) and the terminal flag is “00” (F ₄ ) To do. If the next received data is a DHCP broadcast (F
₅ ) and perform DHCP processing (F ₆ ). Also, it sets the terminal flag to "01" and (F _7), it is possible to access.

-2.1 Addition of communication terminal and network
The operation when the address is a dynamic address is as follows. Communication end
Network flag (F₁)When
Terminal flag (F _Two) Is read and the network flag is "0"
Confirm that (F_Three) And the terminal flag is not "00"
Confirm that (F₁₂) Do. Also, if the terminal flag is "01"
If there is (F_Thirteen) Access is possible. -2.2 The communication terminal has a dynamic address and
The operation when the address is a static address is as follows. Communication
The network flag (F
₁) And terminal flag (F _Two), Read the network flag
Is not "0" (F_Three) And the terminal flag is "00"
Confirm that it is not (F_Four) Do. In addition, the terminal flag is "0
1 "(F_Thirteen) Access is possible.

FIG. 25 shows an example 1 of an address reception flow from the DHCP server. In this example, the communication terminal and the network set a dynamic address. The procedures A _{1 to} A ₉ are as follows. A ₁ ... Turn on the power of the communication terminal. A ₂ ... A DHCP connection request is always broadcast when the power is turned on. A ₃ ... The connection device receives (A ₂ ). After confirming that the network flag is "0", the terminal flag is set to "01". A ₄ ... Requests processing from the DHCP server. A ₅ ... Responds to the processing. A ₆ ... A ₅ response is received. A ₇ ... Flows the processing response to the communication terminal and acquires the address. A ₈ ... Power supply to the communication terminal is cut off. Since the link is broken at A ₉ ... A ₈ , the information of the network flag and the terminal flag is cleared.

FIG. 26 shows an example 2 of an address reception flow from the DHCP server. In this example, the communication terminal has a static address and the network has a dynamic address. The procedures B _{1 to} B ₁₅ are as follows. B ₁ ... Turns on the communication terminal. B ₂ ... ARP (Address Resolution Pr)
otocol: address resolution protocol). B ₃ ... The connecting device receives B ₂ . After confirming that the network flag is "0", the terminal flag is set to "10". Also, the static address and physical (MAC) address of the communication terminal are detected from the received IP packet, the static address is registered in the address conversion table, and the MAC address is registered in the spare buffer. B 4 _... using the MAC address of the pre-buffer DHC
Request address from P server. B ₅ ... Responds to the processing. B ₆ ... B ₅ is received, the assigned address is registered in the address conversion table, and a conversion table with the communication terminal is created. B 7 _... and returns a response to the communication terminal. B ₈ ... Requests access to another server. B ₉ ... Receives the access request and performs address conversion. B ₁₀ ... Make an access request to the server with the converted address. B ₁₁ ... Returns a response to the request. B ₁₂ ... Return to the address of the communication terminal. B ₁₃ ... Returns a response to the communication terminal. B ₁₄ ... Power supply to the communication terminal is cut off. B _{15 ...} because the link is broken at B _14, the network flags and terminal flag, the reserve buffer information is cleared.

FIG. 27 shows an example of a data transmission / reception flow from the communication terminal 7b to the server 15. In this example, the communication terminal 7
This is an example when a static address is set in b and the server 15. When the NAT function is not used, the server can be directly accessed. The procedure C _{1 to} C
₁₂ is as follows. C ₁ ... Turns on the communication terminal. Always ARP at the time of C 2 _... the power is turned on to broadcast. C ₃ ... The connection device receives C ₂ and registers information in the IP address conversion table and the terminal flag. C ₄ ... Communicates the reception and communication path to the communication terminal. C ₅ ... The communication terminal (IP: 20.20.200) requests the server (IP: 200.10.2.30) for processing. C ₆ ... The connection device receives and converts the IP address of the communication terminal into “200.10.2.11”. C ₇ ... Converted address of connected device (IP: 200.1
0.2.11) requests processing to the server. C ₈ ... From server to communication terminal (converted IP: 200.1
The processing response is returned to 0.2.11). C ₉ ... The connection device receives and converts the IP address into the original communication terminal address (IP: 20.20.20.100). C ₁₀ ... Returns the processing response of the server from the connection device to the communication terminal. C ₁₁ ... Power of communication terminal is cut off. Since the link is disconnected at C ₁₂ ... C ₁₁ , the terminal flag of the connecting device is cleared, and at the same time, the conversion table information of the connecting port is cleared.

FIG. 28 shows an address translation flow when the server accesses the communication terminal. If the communication terminal is not connected, check the terminal flag when requesting access from the server (F
₃₁ ) and confirm (F ₃₂ ) whether the terminal flag is cleared (“00”). In this case, a connection error (F _{3 5} ) occurs. If the communication terminal has a fixed IP address, check the terminal flag when requesting access from the server (F
₃₁ ), and it is confirmed (F ₃₂ ) whether the terminal flag is cleared (“00”). The terminal flag is set to DHCP (“0
If it is not 1 "), the address is converted (F ₃₄ ) and the communication terminal is accessed. When the communication terminal is set to DHCP, the terminal flag is confirmed (F when the access request is made from the server).
₃₁ ), and it is confirmed (F ₃₂ ) whether the terminal flag is cleared (“00”). The terminal flag is set to DHCP (“0
If it is 1 "), the communication terminal is accessed.

FIG. 29 shows that the server 15 transfers to the communication terminal 7b.
An example of the data transmission / reception flow of is shown. In this example, the communication terminal 7
This is an example when a fixed IP address is set in b.
It If you do not use the NAT function, use a normal network.
It is the same as the connection. Step D ₁~ D₁₅Is as follows
is there. D₁… Turn on the communication terminal. D_Two… Arp always broadcasts when power is turned on
It D_Three... Connecting device is D_TwoTo receive the IP address translation
Register information in Bull and terminal flags. D_Four… Notify the communication terminal of reception and communication route. D₅... Server (IP: 200.10.2.30) communicates
Requires processing to terminal (conversion IP: 200.10.2.11)
Request. D₆... The connection device receives the IP address of the communication terminal
Conventional IP address (IP: 20.20.200)
Convert to. D₇... Requests processing from the connection device to the communication terminal. D₈... Returns a processing response from the communication terminal to the server. D₉... The connection device receives and sets the address of the communication terminal to "20
0.10.2.11 ". D₁₀... The processing response of the communication terminal is sent from the connection device to the server.
return. D₁₁… Power off of communication terminal. D₁₂... D₁₁Since the link is disconnected at
The terminal flag is cleared, and at the same time the connection port conversion
Bull information is cleared. D_Thirteen... Server 15 (IP: 200.10.2.30)
Is a communication terminal 7b (conversion IP: 200.10.2.11)
Request processing. D₁₄... D₁₂With terminal flag and address conversion table
No response because it has been cleared. D₁₅… Returns a connection error to the server.

[0041]

According to the present invention, when moving a communication terminal or making a new connection, a smooth connection can be made without inquiring to the network administrator. Further, according to the present invention, even if a fixed IP address is set by mistake, connection can be made without trouble by address conversion. Further, according to the present invention, since the IP address is allocated to each port, it is easy to pursue a communication terminal that uses the IP address that causes a network failure. Therefore, for presentations, demonstrations, etc., there is no setting or erroneous setting of communication terminals for a network that is temporarily used, and the network operates stably.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a network connection device of the present invention.

FIG. 2 is an explanatory diagram of a combination of a current network environment and communication terminal settings.

FIG. 3 is a diagram corresponding to the combination 1 of FIG.

FIG. 4 is a diagram showing an example of address setting for combination 1 of FIG.

5 is a diagram showing an example of address setting for combination 1 in FIG.

FIG. 6 is a diagram corresponding to the combination 2 of FIG.

FIG. 7 is a diagram showing an example of address setting for combination 2 in FIG.

FIG. 8 is a diagram corresponding to the combination 3 of FIG.

FIG. 9 is a diagram showing an example of address setting for combination 3 in FIG.

FIG. 10 is a diagram corresponding to the combination 4 of FIG.

FIG. 11 is a diagram showing an example of address setting for combination 4 of FIG.

FIG. 12 is an appearance example of a network connection device of the present invention.

FIG. 13 is a network connection configuration example to which the network connection device of the present invention is applied.

FIG. 14 is a flow of a LAN side address setting determination function only when power is turned on.

FIG. 15 is a content set as default.

FIG. 16 is a state of a network flag.

FIG. 17 is an explanatory diagram of NAT.

FIG. 18 is an explanatory diagram of DHCP.

FIG. 19 is an IP address conversion table.

FIG. 20 shows a terminal flag state and an IP address setting state of a communication terminal.

FIG. 21 is a transition of a LAN state and a network flag.

FIG. 22 is a transition of a state of a communication terminal and a terminal flag.

FIG. 23: Flow of address conversion (communication terminal → server)
Is.

FIG. 24 is a flow of an address conversion diagram (communication terminal → server).

FIG. 25 is an example 1 of an address acquisition flow from a DHCP server.

FIG. 26 is an example 2 of an address acquisition flow from a DHCP server.

FIG. 27 is an example of an access flow to a server.

FIG. 28 is an address conversion flow (server → communication terminal).

FIG. 29 is an example of a flow at the time of transmitting / receiving data (server → communication terminal).

[Explanation of symbols]

1 connection device 2 memory 3 (3a, 3b, 3c) terminal flag section 4 (4a, 4b, 4c) ports 1-n 5 (5a, 5b, 5c) switch 6 processing section 7 (7a, 7b, 7c) Communication terminal

Continued front page    (72) Inventor Hiromasa Yamaoka             5-2-1 Omika-cho, Hitachi City, Ibaraki Prefecture             Information Control Systems Division, Hitachi, Ltd.             Within (72) Inventor Akio Yoshizawa             5-2-1 Omika-cho, Hitachi City, Ibaraki Prefecture             Information Control Systems Division, Hitachi, Ltd.             Within (72) Inventor Yasuyuki Bito             5-2-1 Omika-cho, Hitachi City, Ibaraki Prefecture             Information Control Systems Division, Hitachi, Ltd.             Within F term (reference) 5K033 AA03 CB08 CC01 DA01 DA06                       DA15 DB19 EC03

Claims (6)

[Claims] 1. An L using an internet protocol
AN, one or more communication terminals, the communication terminals and the LAN
In a network connection device having a plurality of ports for connecting to each other, a LAN side address setting determination means for determining whether the IP address allocation method of the LAN is static allocation or dynamic allocation, and IP address allocation of each connected communication terminal Communication terminal address setting judging means for judging whether the method is static allocation or dynamic allocation, and address allocation on the LAN side and / or the communication terminal side according to the combination of the LAN side address setting judgment result and the communication terminal address setting judgment result. Allocation means for performing
A network connection device comprising: 2. When the LAN side is statically assigned and the communication terminal is statically set, the assigning means assigns the static address set in the communication terminal to a static address previously assigned to the port for connection. If the LAN side is dynamically assigned and the communication terminal is statically set, L
When a dynamic address is assigned to the port on the AN side, the static address set in the communication terminal is converted to an address assigned to the port on the LAN side, and when the LAN side is statically assigned and the communication terminal side is dynamically set,
When a static address is assigned to the communication terminal in advance by the administrator on the LAN side port and the LAN side is dynamically assigned and the communication terminal side is dynamically set,
In response to the address allocation request from the communication terminal to the network connection device, the LAN side requests the address allocation, and the LA
The network connection device according to claim 1, wherein a dynamic address assigned from the N side is assigned to the communication terminal. 3. A memory for holding a static address set by an administrator for a port, a memory for holding a flag for identifying a communication terminal address setting determination result, and a conversion between an address of a communication terminal and an address set for a port. 3. The network connection device according to claim 1, further comprising an address conversion table for performing the operation and holding information by supplying power. 4. The LA is provided for each port to which the communication terminal is connected.
4. The network connection device according to claim 1, further comprising a switch for invalidating the allocation according to the combination of the N-side address setting determination result and the communication terminal address setting determination result. 5. An L using an internet protocol
AN, one or more communication terminals, the communication terminals and the LAN
A method for assigning an IP address in a network connection device having a plurality of ports for connecting a
Determine whether the address allocation method is static allocation or dynamic allocation, determine whether the IP address allocation method of each connected communication terminal is static allocation or dynamic allocation, and determine the LAN side address setting judgment result and communication terminal An IP address allocation method for a network connection device, characterized in that addresses are allocated on a LAN side and / or a communication terminal side according to a combination of address setting determination results. 6. When the LAN side is statically assigned and the communication terminal is statically set, the address is assigned to a static address assigned to a port in advance for connection. If the LAN side is dynamically assigned and the communication terminal is statically set, L
When a dynamic address is assigned to the port on the AN side, the static address set in the communication terminal is converted to an address assigned to the port on the LAN side, and when the LAN side is statically assigned and the communication terminal side is dynamically set,
When a static address is assigned to the communication terminal in advance by the administrator on the LAN side port and the LAN side is dynamically assigned and the communication terminal side is dynamically set,
In response to the address allocation request from the communication terminal to the network connection device, the LAN side requests the address allocation, and the LA
The IP address allocation method for a network connection device according to claim 5, wherein a dynamic address allocated from the N side is allocated to the communication terminal.