JP2004171370A - Address control system and method between client/server in redundant constitution - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent both of an active server and a reserve server in duplex servers from acting as active servers in detecting a fault caused by health check between the active server and the reserve server. <P>SOLUTION: The active server 1 comprises an isolation determination part 112 for determining the isolation of the server 1 itself by checking the connection of a client 3 through a LAN 901 in detecting the abnormality of the reserve server 2 by health check of a monitoring part 113 and an IP floating control part 111 for invalidating a shared IP address when the isolation is determined. The reserve server 2 comprises an isolation determination part 212 for determining the isolation of the server 2 itself by checking the connection of the client 3 through the LAN 901 when the down of the server 1 is determined by checking the connection of the server 1 through the LAN 901 in detecting the abnormality of the server 1 by the health check of the monitoring part 213 and an IP floating control part 211 for validating the shared IP address when no isolation is determined. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a client / server address control method and method in a redundant configuration, and more particularly, to a client / server address control method and method in a redundant configuration that performs a health check between an active server and a standby server. .
[0002]
[Prior art]
Conventionally, as a method of performing a health check between servers in a redundant configuration of servers and switching a standby server to an active server, for example, JP-A-2001-344125 and JP-A-2001-344125 disclose such methods. According to Japanese Patent Application Laid-Open No. 2001-344125, the standby server performs a health check on the active server, and when it is recognized as down by the health check, the logical address of the own server is activated. The own server is switched from the standby system to the active system, and the logical address of the other server is activated via the LAN transmission path and another plurality of lines, thereby switching the other server from the active system to the standby system.
[0003]
According to Japanese Patent Application Laid-Open No. 2000-324121, the active server and the standby server mutually perform a health check via a health check line, and when a failure is detected, the health check is performed via a plurality of LAN paths. Is performed, and when all of them fail, it is determined that the other server has failed. If the server in the standby system is determined to be the partner server, the server is switched from the standby system to the active system.
[0004]
[Patent Document 1]
JP 2001-344125 A
[Patent Document 2]
JP 2000-324121 A
[0005]
[Problems to be solved by the invention]
However, according to JP-A-2001-344125, after a standby server detects a failure of a partner server by a health check, the standby server switches from the active system to the standby system using a plurality of paths to the partner server. An instruction to switch is issued, but in the case of a communication failure of the partner server, the switching instruction is not transmitted to the partner server, so that there is a problem that both servers become active systems.
[0006]
Further, according to the above-mentioned Japanese Patent Application Laid-Open No. 2001-344125, it is necessary to prepare a plurality of lines different from the LAN, so that it is necessary to prepare communication software and several types of hardware corresponding to the communication software, resulting in high cost. There is a problem.
[0007]
According to Japanese Patent Laid-Open Publication No. 2000-324121, if a communication failure occurs in an active server, a health check between the servers results in an error. Therefore, a health check is performed via a LAN path. However, even if a health check is performed via the LAN path, it is determined that the partner server has failed, so that both servers determine that the partner server is down, and both servers transition to the active system. In other words, since both servers become the active system, the dual configuration using the IP floating control method has a problem that the two servers have the same IP address.
[0008]
SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to prevent a redundant server from becoming an active system when a failure is detected by a health check between an active server and a standby server.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, an address control method between a client and a server in a redundant configuration according to the present invention is a method in which a plurality of clients are connected to a first network and an active server and a standby server having the same IP address. In an address control method between a client and a server in a redundant configuration, wherein the health check is performed between an active server and a standby server via a second network, the active server is configured by the health check. A first isolation determining unit configured to determine whether the server is isolated by performing a connection check of the client via the first network upon detecting an abnormality of the standby server; If the isolation determining unit determines that the IP address is isolated, the IP address is invalidated to be in a standby state. And a first transition unit that transits, wherein when the standby server detects an abnormality of the standby server by the health check, the standby server confirms connection of the active server via the first network. And a down determination unit for determining whether or not the active server is down, and when the down determination unit determines that the active server is down, the client is connected via the first network to confirm the connection of the own server, thereby isolating the server. A second isolation determining unit for determining whether the IP address is not isolated, and a second status transitioning to a working state by validating the IP address when the second isolation determining unit determines that the device is not isolated. And transition means.
[0010]
Further, in the above-described address control method between the client and the server in the redundant configuration, the first isolation determining means has means for confirming the connection of the client by executing a ping command, and the down determining means includes: Executing the ping command to check the connection of the active server, and the second isolation determining means executes the ping command to check the connection of the client. It is characterized by having.
[0011]
Further, in the above-described address control method between the client and the server in the redundant configuration, the first transition means may invalidate the MAC address when the first isolation determination means determines that the MAC address is isolated. Wherein the second transition means includes means for validating the MAC address when the second isolation determination means determines that the MAC address is not isolated.
[0012]
Further, in the address control method between the client and the server in the above-mentioned redundant configuration, the first and second isolation determining means determine that the own server is not isolated if at least one of the plurality of clients can be confirmed. It is characterized by having a means for performing.
[0013]
Further, in the above-described address control method between the client and the server in the redundant configuration, the first and second isolation determining means may determine that the own server is isolated unless one of the plurality of clients can be confirmed. It is characterized by having means for determining.
[0014]
Further, in the above-described address control method between a client and a server in the redundant configuration, the first and second isolation determining means may isolate the server if a predetermined number or more of the plurality of clients cannot be confirmed. It is characterized by having means for judging that the operation is performed.
[0015]
Further, in the address control method between a client and a server in the redundant configuration according to the present invention, a plurality of clients are connected to a first network, the system comprises an active server and a standby server having the same IP address. An address control method between a client and a server in a redundant configuration in which a health check is performed between an active server and a standby server via a network, wherein the active server performs a health check on the standby server by the health check. When an abnormality is detected, a first determination is made as to whether or not the server is isolated by confirming the connection of the client via the first network, and as a result of the first determination, the server is isolated. When it is determined that the IP address is invalidated, the standby server transitions to the standby state, and the standby server When an error of the standby server is detected by the check, a second determination is made as to whether the active server is down by checking the connection of the active server via the first network, and If it is determined that the server is down as a result of the determination of 2, the third determination of whether or not the server is isolated is performed by confirming the connection of the client via the first network, and the third determination is performed. As a result, when it is determined that the IP address is not isolated, the IP address is validated to transition to the working state.
[0016]
Further, in the above-described address control method between a client and a server in the redundant configuration, the first determination is to confirm connection of the client by executing a ping command, and the second determination is to execute the ping command by executing the ping command. By executing the command, the connection of the active server is confirmed, and in the third determination, the connection of the client is confirmed by executing the ping command.
[0017]
Further, in the above-described address control method between a client and a server in the redundant configuration, when transitioning to the standby state, the MAC address is invalidated when it is determined that the first state is isolated, and the active state is determined. When the third determination is made that the MAC address is not isolated, the MAC address is validated.
[0018]
Further, in the above-described address control method between a client and a server in the redundant configuration, the first and third determinations may include determining that the own server is not isolated if at least one of the plurality of clients can be confirmed. It is characterized by.
[0019]
Further, in the above-described address control method between a client and a server in a redundant configuration, the first and third determinations may include determining that the own server is isolated if at least one of the plurality of clients cannot be confirmed. It is characterized by.
[0020]
Further, in the above-described address control method between a client and a server in the redundant configuration, the first and third determinations may be made such that the server is isolated unless a predetermined number or more of the plurality of clients can be confirmed. It is characterized by judging that there is.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0022]
Referring to FIG. 1, two redundant servers 1 and 2, a client 3 which is a user operation terminal, an existing operation LAN 901, and a health between the redundant servers 1 and 2 It comprises a LAN 902 for checking and the communication device 4.
[0023]
The server 1 includes a control unit 11 that operates under program control by a processor (CPU) (not shown), a LAN interface unit 12 that exchanges data with the LAN 901, a LAN interface unit 13 that exchanges data with the LAN 901, and a server. The LAN interface unit 14 exchanges data with the LAN 2 and a timer 15 monitors time.
[0024]
The server 2 includes a control unit 21 that operates under program control by a processor (CPU) (not shown), a LAN interface unit 22 that exchanges data with the LAN 901, a LAN interface unit 23 that exchanges data with the LAN 901, 1 includes a LAN interface unit 24 for exchanging data with the communication device 1 and a timer 25 for monitoring time.
[0025]
The duplicated server 1 and server 2 are connected to the LAN 901 with the same IP address, and the server in the active state (active system) has an IP address control method for validating the IP address (hereinafter, referred to as “server”). This control method is called an IP floating method, and its IP address is called a floating IP address), and a server in a standby state (standby system) invalidates the floating IP address. Therefore, the client 3 is configured to be able to connect to the active server by connecting to the floating IP address.
[0026]
The control unit 11 of the server 1 includes an IP floating control unit 111, an isolation determination unit 112, and a monitoring unit 113.
[0027]
The IP floating unit 111 of the server 1 assigns (enables) a floating IP address to the LAN interface unit 13 to activate the transmission / reception circuit inside the LAN interface unit 13 when the active state is set at the time of startup, Means for assigning (enabling) a floating IP address to the LAN interface unit (13) and enabling the transmission / reception circuit inside the LAN interface unit (13) when the isolation determining unit (112) determines that the server (2) is isolated in the standby state. If the isolation determining unit 112 determines that the server 1 is isolated in the active state, the floating IP address is released (invalidated) and the transmission / reception circuit inside the LAN interface unit 13 is invalidated, so that the standby state is established. Means.
[0028]
When the monitoring unit 113 detects an abnormality in the server 2 in the standby state, the isolation determination unit 112 of the server 1 determines whether the server 2 is down by executing the ping command to determine whether the server 2 is down via the LAN 901. A ping command when the server 2 is determined to be down in the standby state or when the monitoring unit 113 detects an abnormality in the server 2 in the active state by executing the ping command via the LAN 901. Means for determining whether the server 1 itself is isolated by checking the connection state with the client 3.
[0029]
The monitoring unit 113 of the server 1 has means for performing a health check of the server 2 by using (executing) the ping command via the health check LAN 902 by a timer interrupt of the timer 15. The ping (Packet Internet Grouper) command is a command for confirming whether devices are connected on a network. That is, the monitoring unit 113 issues an ICMP (Internet Message Protocol) echo request by executing the ping command, and confirms an ICMP echo response returned by the server 2 as a response.
[0030]
The LAN interface unit 12 of the server 1 is assigned a real IP address of the server 1 and a MAC address corresponding to the real IP address to distinguish it from the server 2. In the present invention, the LAN interface unit 12 does not have to exist.
[0031]
The same MAC address as that of the LAN interface unit 23 is assigned to the LAN interface unit 13 of the server 1, and when the server 1 is in the active state, the floating IP address is assigned and the transmission / reception circuit is activated (in the LAN interface unit 13). Activating the transmission / reception circuit described above also activates the MAC address). In this case, the floating IP address is set in the LAN interface unit 13 in advance, and the standby state, that is, the floating IP address is invalidated (including the invalidation of the transmission / reception circuit in the LAN interface unit 13, that is, the invalidation of the MAC address). Alternatively, in the case of the active state, the floating IP address may be validated (including the validation of the transmission / reception circuit in the LAN interface unit 13, that is, the validation of the MAC address) so that transmission and reception with the LAN 901 may be performed.
[0032]
The LAN interface 14 of the server 1 is assigned the IP address of the server 1 for health check and the MAC address corresponding to the IP address.
[0033]
When activated, the timer 15 of the server 1 interrupts the control unit 11 after a predetermined time.
[0034]
The control unit 21 of the server 2 includes an IP floating control unit 211, an isolation determination unit 212, and a monitoring unit 213.
[0035]
The IP floating unit 211 of the server 2 assigns (enables) a floating IP address to the LAN interface unit 23 to activate the transmitting / receiving circuit inside the LAN interface unit 23 when the active state is set at the time of startup, Means for assigning (enabling) a floating IP address to the LAN interface unit (23) and enabling the transmission / reception circuit inside the LAN interface unit (23) when the isolation determining unit (212) determines that the server (1) is isolated in the standby state. When the isolation determination unit 212 determines that the server 2 is isolated in the active state, the floating IP address is released (invalidated) and the transmission / reception circuit inside the LAN interface unit 23 is invalidated to set the standby state. Means.
[0036]
When the monitoring unit 213 detects an abnormality in the server 1 in the standby state, the isolation determination unit 212 of the server 2 determines whether the server 1 is down by executing the ping command to determine whether the server 1 is down via the LAN 901. And the LAN 901 by executing a ping command when the monitoring unit 213 detects that the server 1 is down in the standby state or when the monitoring unit 213 detects an abnormality of the server 1 in the active state. Means for determining whether the server 2 itself is isolated by checking the connection state with the client 3.
[0037]
The monitoring unit 213 of the server 2 has means for performing a health check of the server 2 by using (executing) the ping command via the LAN 902 for health check by a timer interrupt of the timer 25. That is, the monitoring unit 213 issues an ICMP (Internet Message Protocol) echo request by executing the ping command, and confirms an ICMP echo response returned by the server 2 as a response.
[0038]
The LAN interface unit 22 of the server 2 is assigned a real IP address of the server 1 and a MAC address corresponding to the real IP address in order to distinguish it from the server 1. In the present invention, the LAN interface unit 22 need not be provided.
[0039]
The same MAC address as that of the LAN interface unit 13 is assigned to the LAN interface unit 23 of the server 2, and when the server 2 enters the active state, the floating IP address is assigned and the transmission / reception circuit is activated (the transmission / reception circuit is activated). By doing so, the MAC address is also enabled). In this case, the floating IP address is set in the LAN interface unit 23 in advance, and the standby state, that is, the floating IP address is invalidated (including the invalidation of the transmission / reception circuit in the LAN interface unit 23, that is, the invalidation of the MAC address). In the active state, the floating IP address may be validated (including the activation of the transmission / reception circuit in the LAN interface unit 23, that is, the activation of the MAC address) to enable transmission and reception with the LAN 901.
[0040]
The LAN interface 24 of the server 2 is assigned the IP address of the server 2 for health check and the MAC address corresponding to the IP address.
[0041]
When activated, the timer 25 of the server 2 interrupts the control unit 21 after a predetermined time.
[0042]
When the LAN interface unit 13 and the LAN interface unit 23 are in the operating state, one of them is valid, and the same floating IP address and the same MAC address are used.
[0043]
The client 3 includes, for example, an application 31 which is communication application software for accessing a shared database managed by the server 1 and the server 2.
[0044]
Next, the operation of the embodiment of the present invention will be described with reference to the drawings with reference to FIGS.
[0045]
When the server 1 of the system 0 is started, the control unit 11 of the server 1 assigns the real IP address of the server 1 to the LAN interface unit 12 and starts the IP floating control unit 111. When the IP floating control unit 111 assigns a floating IP address to the LAN interface unit 13 and the control unit 11 confirms that the IP floating control unit 111 has started up normally, the control unit 11 makes a transition to the working state. Further, by activating the timer 15, the control unit 11 activates the isolation determining unit 112 and the monitoring unit 113 (Steps A11 to A15 in FIG. 2).
[0046]
On the other hand, when the server 2 of the first system is started, the control unit 21 of the server 2 assigns the real IP address of the server 1 to the LAN interface unit 22 and starts the IP floating control unit 211. When the IP floating control unit 211 does not assign the floating IP address to the LAN interface unit 23, and the control unit 21 confirms that the IP floating control unit 4 has started up normally, the control unit 21 shifts to the standby state. Further, the control unit 21 activates the timer 25 to activate the isolation determining unit 212 and the monitoring unit 213 (steps B11 to B14 in FIG. 4).
[0047]
The client 3 executing the application 31 accesses the server using the floating IP address to communicate with the server, but can access the server 1 in the active state without being aware of the state of the server. become.
[0048]
On the other hand, when the monitoring unit 113 of the server 1 executes the ping command in order to periodically check the health of the server 2 by the timer interruption of the timer 15, the monitoring unit 113 transmits the ICMP to the server 2 via the LAN interface unit 14 and the LAN 902. Send an echo request. When receiving the ICMP echo request via the LAN interface unit 902, the control unit 21 of the server 2 returns an ICMP echo response. Then, the monitoring unit 113 of the server 1 determines that the operation is normal, restarts the timer 15, and ends the processing (steps A21, A22, and A29 in FIG. 3).
[0049]
Similarly, when the ping command is executed by the monitoring unit 213 of the server 2 to periodically perform the health check of the server 1 by the timer interrupt of the timer 25, the monitoring unit 213 sends the ping command to the server 1 via the LAN interface unit 24 and the LAN 902. Send an ICMP echo request. When receiving the ICMP echo request via the LAN interface unit 902, the control unit 11 of the server 1 returns an ICMP echo response. Then, the monitoring unit 213 of the server 2 determines that the operation is normal, restarts the timer 25, and ends the processing (steps B21, B22, and B29 in FIG. 5).
[0050]
As described above, if the result of the health check is normal, the monitoring unit of the server 1 and the monitoring unit 213 of the server 2 periodically perform the health check by the timer interrupt. Assume that it has occurred.
[0051]
When a timer interrupt by the timer 15 occurs in the control unit 11 in the server 1 in the active state, the monitoring unit 113 of the control unit 11 sends a LAN interface unit to the server 2 to check the health of the server 2. When the ping command is issued through the LAN 14 and the LAN 902, no response is returned from the server 2, so that the server 2 determines that the server is abnormal and notifies the isolation determining unit 112 (steps A21, A22, A23).
[0052]
Upon receiving the notification, the isolation determining unit 112 executes the ping command and transmits an ICMP echo request to the client 3 via the LAN interface unit 13 and the LAN 901. Since no echo response is returned, the server 2 is isolated and determines that the server 2 has transitioned to the active state, and notifies the IP floating control unit 111 (processing by abnormal notification). Upon receiving the abnormality notification, the IP floating control unit 11 invalidates the floating IP address to the LAN interface unit 13 and also invalidates the transmission / reception circuit so that the LAN interface unit 13 cannot receive the IP address. Then, the control unit 11 transitions to the standby state and ends (Steps A24 to A28).
[0053]
On the other hand, when a timer interrupt by the timer 25 occurs in the control unit 21 in the server 2 in the standby state, the monitoring unit 213 of the control unit 21 executes a ping command to perform a health check of the server 1. Even if an ICMP echo request is transmitted to the server 1 via the LAN interface unit 24 and the LAN 902, no response is returned from the server 1, so that the server 1 is determined to be abnormal and notified to the isolation determination unit 212 (step B21). , B22, B23).
[0054]
When the isolation determining unit 212 that has received the notification transmits an ICMP echo request to the server 1 via the LAN interface unit 23 and the LAN 901 by executing the ping command, the server 1 does not return an ICMP echo response. Then, it is determined that the server 1 has gone down, and further, the ping command is executed to transmit an ICMP echo request to the client 3 via the LAN interface unit 23 and the LAN 901 to confirm the isolation of the server 2 itself ( Steps B24 to B27).
[0055]
In step B27, when the ICMP echo response is returned from the client 3, the isolation determining unit 212 of the server 2 determines that the server 2 itself is normal, and notifies the IP floating control unit 211 (processing by the normal notification). The IP floating control unit 211 that has received the normal notification of the server 2 activates the floating IP address for the LAN interface unit 23 and also activates the transmission / reception circuit so that the LAN interface unit 23 can receive the IP address. Then, the control unit 21 transitions to the active state, restarts the timer 25 by the monitoring unit 213, and ends (Steps B26 to B31).
[0056]
On the other hand, the client 3 executing the application 31 accesses the server using the floating IP address in order to communicate with the server in the same manner as the previous time, but this time, without being aware of the state of the server, Can access the server 2 switched to the active state.
[0057]
When the ICMP echo response is returned from the server 1 in step B27, the isolation determining unit 212 of the server 2 determines that the server 1 is normal, restarts the timer, and ends (step B31).
[0058]
That is, as shown in FIG. 6, the server 1 transitions from the active state to the standby state, the server 2 transitions from the standby state to the active state, but the floating IP address and the MAC address also transition from the server 1 to the server 2. Therefore, even if the client 3 accesses the server with the floating IP address (and the MAC address), the client 3 can access the normal server 2 without accessing the abnormal server 1.
[0059]
Further, when the downed server 1 is repaired and started up, the server 1 enters a standby state, and when the server 2 detects the above, the server 1 and the server 2 are reversed, and the same operation as described above is performed. Needless to say,
[0060]
In the above description, the connection is confirmed using the ping command between the server 1 in the active state and the client 3 for the purpose of isolation determination. It is not necessary to limit the communication device to a client that communicates with the server 1 or the server 2. Any communication device connected to the LAN 901 may be used. The communication device can respond to an ICMP echo request by a ping command from the server 1 in the active state. Needless to say, there is.
[0061]
In addition, when the active server 1 determines the isolation, the connection confirmation by the ping command is performed by performing the connection confirmation by the ping command from the active server 1 on the LAN 901 to a plurality of clients and other communication devices. It goes without saying that the reliability of the isolation determination is improved. In this case, for example, in step A25 (and step B27), when the server 1 (and server 2) transmits an echo request to a plurality of clients 3 using a ping command, if there is at least one response, the server 1 (and server 2) will normally operate. May be performed, may be normal if all responses are received (not normal if there is no response), or may be a predetermined number (the number in this case is a memory or the like not shown). If there is a response equal to or more than (previously stored in the storage unit), it may be set to normal.
[0062]
As described above, when it is assumed that a fatal failure has occurred in the server 1 in the working state (active system), when the server 1 detects an abnormality in the server 2 in the waiting state (standby system) through a health check, the LAN 901 is activated. When it is determined that the own server 1 is isolated by confirming the connection of the client 3 through the server, the common floating IP address is invalidated to put the server 3 in a standby state, and the server 2 performs a health check on the server 2. When an abnormality is detected, it is determined that the server 1 is down by checking the connection of the server 1 via the LAN 901, and when it is determined that the own server 1 is not isolated by checking the connection with the client 3, a common floating IP address Is activated to make the transition to the active state, so that both the server 1 and the server 2 are switched to the active state. That it can be prevented.
[0063]
【The invention's effect】
As described above, according to the present invention, in addition to the health check function between the redundant servers, when the active server detects an error in the standby server due to the health check, the active server checks the connection with the client, thereby isolating the server itself. If the standby server detects an abnormality in the active server by health check, it checks the connection of the active server and the connection with the client. By doing so, it is determined whether the active server is down and the server itself is isolated. If it is determined that the active server is not down and the own server is not isolated, the state transitions to the active state. There is an effect that both servers can be prevented from becoming active.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.
FIG. 2 is a flowchart showing an operation at the time of starting the server of FIG. 1 which is in an active state;
FIG. 3 is a flowchart showing an operation of the server in the active state of FIG. 1 by a timer interrupt;
FIG. 4 is a flowchart illustrating an operation of the server in FIG. 1 in a standby state when the server is started.
FIG. 5 is a flowchart showing an operation of the server in a standby state in FIG. 1 by a timer interrupt;
FIG. 6 is a schematic configuration diagram showing how the server on the client side looks in the state of the server in FIG. 1;
[Explanation of symbols]
1,2 server
3 clients
11, 21 control unit
12, 13, 14, 22, 23, 24 LAN interface unit
15, 25 timer
31 Application
111, 211 IP floating control unit
112,212 Isolation judgment unit
113, 213 monitoring unit
901 and 902 LAN

Claims (12)

A plurality of clients are connected to the first network, and are configured by an active server and a standby server having the same IP address. The active server and the standby server have a mutual health via the second network. In the address control method between the client and the server in the redundant configuration for performing the check, when the active server detects an abnormality of the standby server by the health check, the active server checks the connection of the client via the first network. First isolation determining means for determining whether the own server is isolated,
A first transition unit that transitions to a standby state by invalidating the IP address when the first isolation determination unit determines that it is isolated,
When the standby server detects an abnormality of the standby server by the health check, the standby server determines whether the active server is down by checking the connection of the active server via the first network. Down determining means;
A second isolation determination unit that determines whether the server is isolated by performing connection confirmation of the client via the first network when the down determination unit determines that the server is down;
A second transition unit that transitions to an active state by validating the IP address when the second isolation determination unit determines that the client is not isolated. Address control method between servers. The first isolation determination unit has a unit that confirms the connection of the client by executing a ping command,
The down determining means has means for confirming connection of the active server by executing the ping command,
2. An address control method between a client and a server in a redundant configuration according to claim 1, wherein said second isolation determining means has means for confirming connection of said client by executing said ping command. The first transition unit includes a unit that invalidates a MAC address when the first isolation determination unit determines that the MAC address is isolated,
2. The client / client in a redundant configuration according to claim 1, wherein the second transition unit has a unit that validates the MAC address when the second isolation unit determines that the MAC address is not isolated. Address control method between servers. 4. The apparatus according to claim 1, wherein the first and second isolation determining means include means for determining that the server is not isolated if at least one of the plurality of clients can be confirmed. An address control method between a client and a server in the redundant configuration described above. 4. The method according to claim 1, wherein the first and second isolation determining means include means for determining that the server is isolated if at least one of the plurality of clients cannot be confirmed. 3. An address control method between a client and a server in the redundant configuration according to 3. 2. The apparatus according to claim 1, wherein the first and second isolation determining means include means for determining that the server is isolated if a predetermined number or more of the plurality of clients cannot be confirmed. , 2, or 3, the address control method between the client and the server in the redundant configuration. A plurality of clients are connected to the first network, and are configured by an active server and a standby server having the same IP address. The active server and the standby server have a mutual health via the second network. An address control method between a client and a server in a redundant configuration for performing a check, wherein the active server confirms connection of the client via the first network when detecting an abnormality of a standby server by the health check. Performs a first determination of whether the server is isolated,
As a result of the first determination, when it is determined that the IP address is isolated, the IP address is invalidated to transition to a standby state,
When the standby server detects an abnormality of the standby server by the health check, the standby server checks the connection of the active server via the first network to determine whether the active server is down. Is determined,
As a result of the second determination, if it is determined to be down, a third determination of whether the server is isolated by performing a connection check of the client via the first network,
As a result of the third determination, when it is determined that the IP address is not isolated, the IP address is validated and a transition is made to a working state. The first determination is to confirm the connection of the client by executing a ping command,
The second determination is to confirm the connection of the active server by executing the ping command,
8. The address control method between clients and servers in a redundant configuration according to claim 7, wherein in the third determination, the connection of the client is confirmed by executing the ping command. When transitioning to the standby state, invalidate the MAC address when it is determined in the first determination that it is isolated,
8. The address between a client and a server in a redundant configuration according to claim 7, wherein when transitioning to the working state, the MAC address is validated when it is determined in the third determination that the MAC address is not isolated. Control method. 10. The redundant configuration according to claim 7, wherein the first and third determinations determine that the own server is not isolated if at least one of the plurality of clients can be confirmed. Address control method between client / server. 10. The redundant configuration according to claim 7, wherein the first and third determinations determine that the own server is isolated if at least one of the plurality of clients cannot be confirmed. Address control method between client / server. 10. The method according to claim 7, wherein the first and third determinations determine that the server is isolated if a predetermined number or more of the plurality of clients cannot be confirmed. An address control method between a client and a server in the redundant configuration described above.

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