JPH08237287A - Lan physical address system for substitutional interface device - Google Patents

Abstract

PURPOSE: To prevent the break of communication due to the change of a LAN physical address after the switching of an interface device by reading the LAN physical address out of the ROM of a master interface device and writing it in a RAM when starting a system. CONSTITUTION: A control program having started execution reads the LAN physical address out of the ROM in the master interface device 1. The read out LAN physical address is written in a specified area in a memory 5 for control. The control program writes the LAN physical address of the master interface device 1 written in the specified area of the memory 5 for control in the RAM of the substitutional interface device 2. Since the substitutional interface device itself has no LAN physical address, but uses the LAN physical address of the master interface device, the change of the LAN physical address is not caused even if the master interface device is switched to the substitutional interface device, and the break of the communication can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention duplicates an interface device and a channel for connecting to a LAN in a system such as a server and a workstation, and causes a failure in a main interface device or a failure in a channel connected to the main interface device. When an error occurs, switching to the alternative interface device without operator intervention and using the LAN physical address of the main interface device as the LAN physical address of the alternative interface device
The present invention relates to a device characterized by preventing communication interruption due to a change in AN physical address.

[0002]

2. Description of the Related Art The downsizing of computer systems has progressed, and systems for satisfying one purpose such as a file server and a printer server are distributed and arranged, and a "client-server type" in which a plurality of clients use this system. “System” is becoming popular.

In these "client-server type systems", stopping the system that serves as a server causes a great hindrance to business.

Therefore, high reliability is required for the systems that serve as these servers, and quick recovery is required in the event of a failure.

By the way, as a method of providing high reliability and redundancy to such a server system, a method of duplicating an interface device and a channel can be considered for the LAN connection part.

However, in the conventional duplexing of the interface device and the channel, when the interface device and the channel are switched from the main to the alternative when a failure occurs, the LAN physical address also changes from the main to the alternative. The problem of communication interruption occurs due to the change of physical address.

[0007]

In the above-mentioned duplexing of the interface device according to the prior art, the change in the LAN physical address is not taken into consideration, and there is a problem of communication interruption.

The cause of the communication interruption is that the system that initiates (requests) the communication uses the "logical address" and the "OSI reference model 2 lower than the communication protocol" used in the communication protocol of the communication partner system. The table holds the correspondence with "LAN physical address used in layer level communication", and a communication request is sent to the address based on this correspondence. This is because even if the address has changed, a communication request is issued at the address of the old address held in the table unless the changed new address is known.

In order to restore communication in such a case,
It is necessary to have a new correspondence in the table of the system that initiates (requests) communication. As a method, the operator can restart the system to delete the old correspondence or the operator can use the command to operate the old correspondence. There is a method of deleting a message and dynamically holding a new correspondence by an address resolution protocol such as ARP (Address Resolution Protocol), but this causes a long communication interruption. .

Therefore, an object of the present invention is to provide a system capable of preventing communication interruption due to a change in the LAN physical address even when the interface device is switched in a system in which the interface device is duplicated. It is to provide a LAN physical address system for the interface device.

[0011]

In order to achieve the above object, the LAN physical address system of the alternative interface device of the present invention is (a) the main interface device has a LAN physical address stored in its own ROM by a control program. (B) The alternative interface device uses a RAM as a LAN physical address storage part which is a ROM in the conventional interface device, and the alternative interface device itself does not hold the LAN physical address. L written in RAM by control program
It has a function of using the AN physical address as the LAN physical address of its own interface device, and (c) the control program reads the LAN physical address from the ROM of the main interface device at system startup without operator intervention, and this LAN physical address To the RAM of the alternate interface device and to monitor the status of both the main and alternate interface devices, including the channels,
It is realized by the function of displaying various information.

[0012]

The LAN of the alternative interface device according to the present invention
In the physical address method, the alternative interface device itself is L
By not using the AN physical address and using the LAN physical address of the main interface device, even when the main interface device is switched to the alternative interface device, the LAN physical address does not change and the LA physical address does not change.
It is possible to prevent the communication interruption due to the change of the N physical address.

In addition, the control program is the ROM of the main interface device when the system is started without operator intervention.
Since the LAN physical address is read from and is written in the RAM of the alternative interface device, the operator does not need to be aware of the LAN physical address of the interface device.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an example of a connection configuration of a system using the present invention.

In FIG. 1, 10 is a file server system, 11 is a network connection unit, and 12 is a client system.

FIG. 2 is a schematic block diagram showing an example of the construction of the network connection unit 11 of FIG.

In FIG. 2, 0 is an interface controller, 1 is a main interface device, 2 is an alternative interface device, 3 is a control processor, 4 is a status display lamp, 5
Is a control memory, 6 is a control line, 7 is a channel, 8 is a network device, and 9 is a network medium.

FIG. 3 is an internal processing flow from the power-on of the system to the communicable state according to this embodiment.

The network connection unit 11 of FIG. 1 shown in FIG.
In the example of the configuration of one embodiment and the internal processing flow of this embodiment shown in FIG.
Starts executing the control program stored in the control memory 5. (Step 1) The control program started to execute in step 1 reads the LAN physical address from the ROM in the main interface device 1. The read LAN physical address is written in a specific area in the control memory 5 (if there is a LAN physical address already written, it is overwritten). If the main interface device 1 has already failed at this point and reading has failed, the control program turns on the lamp indicating the failure of the status display lamp 4.
(Step 2) After the completion of step 2, the control program is written in a RAM in the alternative interface device 2 in a specific area in the control memory 5, and is the LAN of the main interface device 1.
Write the physical address. When the reading fails due to the failure of the main interface device 1, if the LAN physical address is already written in the specific area in the control memory 5, this is written. (Step 3) After step 3, the control program tests the operation of the main interface device 1, the alternative interface device 2, the channels 7a and 7b, and the network devices 8a and 8b. Creates a LAN physical address written in a specific area in the control memory 5, that is, test data addressed to the main interface device 1 and the alternative interface device 2, and first sends it from the main interface device 1. At that time, the other alternative interface device 2 is logically separated from the control line 6 by the control program. If the control program can receive the sent test data within a fixed time, the main interface device 1 side (including the channel 7a and the network device 8a)
The result of the test is judged to be normal. Next, an operation test is similarly performed on the alternative interface device 2 side (including the channel 7b and the network device 8b).
The test result is represented by the control program by turning on the status display lamp 4. (Step 4) After step 4, the control program uses the main interface device 1 side for communication if it is confirmed by the operation test that the main interface device 1 side is normal.
The alternative interface device 2 is logically disconnected from the control line 6 by the control program and is placed in a standby state. At this time, the control program turns on the lamp indicating that the main interface device 1 side of the status display lamp 4 is for communication. When a failure is detected by the operation test on the main interface device 1 side, if the alternative interface device 2 side is confirmed to be normal by the operation test, the alternative interface device 2 side is used for communication and the main interface The device 1 is logically disconnected from the control line 6 by the control program and put in a standby state. At this time, the control program turns on the lamp indicating that the alternative interface device 2 side of the status display lamp 4 is for communication. If a failure is detected in the operation test on both interfaces, the control program turns on the lamp indicating the failure of the status display lamp 4. (Step 5) After the communication is started, the control program periodically performs a test of the same method as the operation test of the step 4 performed at the time of startup on the interface device side used for the communication. Thereby, the failure is detected. If a failure is detected in this test, the control program logically disconnects the interface device in which the failure is detected from the control line 6 into the standby state, and connects the interface device that has been in the standby state until now. I do. Step 4 at the time of starting the interface device side connected
If the test is performed in the same manner as the operation test of 1. and it is confirmed to be normal, this interface device side is used for communication. Information such as the test result, failure, and which interface device side is used for communication is indicated by the control program lighting the lamps indicating the status display lamps 4.

[0021]

According to the present invention, in the system in which the interface device is duplicated, there is no change in the LAN physical address even when the interface device is switched from the main interface device to the alternative interface device. , It is possible to prevent the communication interruption due to the change of the LAN physical address.

In addition, the control program is the ROM of the main interface device when the system is started without operator intervention.
Since the LAN physical address is read from and written in the RAM of the alternative interface device, the operator does not need to be aware of the LAN physical address of the interface device.

[Brief description of drawings]

FIG. 1 is a connection configuration example of a system using the present invention.

FIG. 2 is a schematic block diagram showing an example of an implementation configuration of the network connection unit 11 of FIG.

FIG. 3 is an internal processing flow from system power-on to an operable state in the embodiment of FIG.

[Explanation of symbols]

 0 ... Interface control unit, 1 ... Main interface device, 2 ... Alternate interface device, 3 ... Control processor, 4 ... Status display lamp, 5 ... Control memory, 6 ... Control line, 7 ... Channel, 8 ... Network device, 9 ... network medium, 10 ... file server system, 11 ... network connection part, 12 ... client system.

Claims (2)

[Claims] 1. A LAN (local area network) physical address is read from a main interface device,
By writing to the alternate interface device, the LAN physical address does not change even if a failure is detected in the main interface device or the channel connected to the main interface device and the alternate interface device is switched. Of the alternative interface device when the interface device is duplicated
N physical address method. 2. The LA of the alternative interface device of claim 1.
In the N physical address method, the main interface device uses its control program to read its own ROM (read only
The alternative interface device uses a RAM (random access memory) for the LAN physical address storage part, which is a ROM in the conventional interface device, and has a function of reading the LAN physical address stored in the memory). , The alternative interface device itself does not have a LAN physical address, and has a function of using the LAN physical address written in RAM by the control program as the LAN physical address of the own interface device, and the control program has no operator intervention. A function of reading the LAN physical address from the ROM of the main interface device at the time of system startup and writing this LAN physical address to the RAM of the alternative interface device, a function of monitoring the states of both the main and alternative interface devices including channels, and various information To Scheme with Shimesuru function.