JPH06177892A - Local area network - Google Patents

Abstract

PURPOSE:To recover a fault and to ensure the maintenance of a local area network without stopping of the network system. CONSTITUTION:At least >=2 work stations 10 are connected to two network devices 1 and 2 which transmit/receive the data. The network controllers 11 and 12 are also connected to the devices 1 and 2 and transmit/receive the data. A comparator 15 compares the contents of the received data with each other. Each of controllers 11 and 12 includes a means which adds the code common to its own station to the data. Meanwhile the comparator 15 includes a means which detects whether a common code is added or not to the data received from both devices 1 and 2. Furthermore each of both controllers 11 and 12 includes a means that decides as a fault when the comparator 15 could not detect the common code and informs all stations of the fault via the network device that normally received the common code.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is used for improving the reliability of data transmission / reception in a multiplexed network system. The present invention relates to a network system capable of performing recovery without stopping the system when a failure occurs.

[0002]

2. Description of the Related Art In a conventional network system, when a network device is duplicated to improve system reliability, a management station and a normal station are divided to detect a failure of the network device. In addition, the communication phase in which data is transferred using the main network device is compared with the data collected by the management station from both network devices, and management is performed to detect that a failure has occurred in one network device due to a mismatch in data content. It was divided into phases. (JP-A-2-60338, JP-A-2-60339)

[0003]

The above-mentioned conventional network system requires a management node, and when the management node fails, the network system failure cannot be detected, and the transferable time is limited. There was a problem.

The present invention solves such a problem, and is capable of detecting a network failure without being affected by a workstation failure and performing data transfer without any time constraint. The purpose is to provide.

[0005]

SUMMARY OF THE INVENTION The present invention is a local area network comprising two bus network devices for transmitting and receiving data, and at least two or more workstations connected to the two network devices. , Each of the workstations is individually connected to the network device to transmit / receive data to / from a specific or all workstations, and each received data is individually connected to each of the two network control devices. It is characterized in that it is provided with two reception data memories stored in, a comparison device for comparing the contents of the two reception data memories, and a display device for displaying a comparison result of the comparison device.

Each of the workstations is provided with a transmission data memory for storing the transmission to the two network devices, and whether the comparison device has a common code added to the data received from the two network devices. And a means for adding a common code to the network control device to the data, and a comparator for judging that the common code is normal when the comparator cannot detect the common code. And means for notifying all said workstations via the received network device.

[0007]

When the workstation receives the data, each of the network control devices provided corresponding to the two network devices examines its destination, and when the data is addressed to itself, the reception data memory receives the data. Write the data. The comparator compares the written data with the common code of the network system, and if the common code is written normally, the data is considered to have been received normally. If the common code is not written normally, it is judged as a failure and an error is displayed on the display device. If the common code is written in only one side of the received data memory, it is assumed that the network device on the side of the received data memory that has not been written normally is faulty and Notify all workstations of the failure via the network control device and network device.

As a result, the failure can be detected in the communication phase without being influenced by the failure of the workstation, and the data transfer can be performed at any time without any time constraint.

[0009]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration according to the embodiment of the present invention, and FIG. 2 is a diagram showing the configuration of a workstation in the embodiment of the present invention.

The embodiment of the present invention comprises two network devices 1 and 2 for transmitting and receiving data, and at least two or more workstations 10-1 to 10-N connected to the two network devices 1 and 2. Two network control devices 11 and 12 each of which is provided in each of the workstations 10-1 to 10-N and is individually connected to the network devices 1 and 2 to transmit / receive data to / from a specific or all workstations, and these two networks. Two reception data memories 1 connected to each of the control devices 11 and 12 and individually storing each reception data
3 and 14, a comparison device (CPU) 15 for comparing the contents of the two reception data memories 13 and 14, and a display device 1 for displaying the comparison result of the comparison device (CPU) 15.
And workstations 10-1 to 10-1.
Two network devices 1 and 2 for each 0-N
And a means for detecting whether or not a common code is added to the data received from the two network devices 1 and 2 in the comparison device (CPU) 15. , A means for adding a code common to its own station to the network control devices 11 and 12, and when the comparison device (CPU) 15 cannot detect the common code, it judges that it is a failure and normalizes the common code. Means for notifying all the workstations 10-1 to 10-N via the received network device.

Next, the operation of the embodiment of the present invention thus constructed will be described. FIG. 3 is a flow chart showing the operation flow of the comparison device (CPU) 15 in the embodiment of the present invention.

When the workstation 10 receives data, the network control device 11 and the network control device 12 check the destination of the received data. If the data is addressed to the own station, the received data memory 13 and the received data memory 14 receive the received data. Write. Received data memory 13
And the content written in the reception data memory 14 and the code common to the network system are compared (CP
U) 15 will be compared.

The operation of the comparison device (CPU) 15 is as follows.
As shown in FIG. 3, two reception data memories 13 and 14 are provided.
Read the contents of to determine whether or not they match. If they match, the same operation is repeated. If they do not match, it is judged whether any one of the common codes SYS1 or SYS2 that holds the common code of the two reception data memories 13 and 14 in advance matches, and if they match. Take out the person who is there.

When the common code in the network system is normally written in the reception data memory 13 and the reception data memory 14, the data reception is normally completed.

When the common code in the network system is not normally written in both the reception data memory 13 and the reception data memory 14, it is judged as a failure and the abnormality is displayed on the display device 17. If the common code in the network system is not normally written in only one of the reception data memory 13 and the reception data memory 14, the common code in the network system is not normally written in the network to which the reception data memory is connected. Diagnose the device as defective. Based on this diagnosis result, all the workstations are notified of the failure by using the network control device and the network device to which the reception data memory in which the common code is normally written in the network system is connected.

[0016]

As described above, according to the present invention, a management node is unnecessary in a multiplexed network system, and a network failure can be detected without being affected by a workstation failure. Since the failure can be detected in the communication phase, there is an effect that the transfer can be performed at any time without any time constraint.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration according to an embodiment of the present invention.

FIG. 2 is a block diagram showing the configuration of a workstation in the embodiment of the present invention.

FIG. 3 is a flowchart showing a flow of operations of a comparison device (CPU) in the embodiment of the present invention.

[Explanation of symbols]

 1, 2 Network device 10, 10-1 to 10-N Workstation 11, 12 Network control device 13, 14 Received data memory 15 Comparison device (CPU) 16 Transmitted data memory 17 Display device

Claims (2)

[Claims] 1. A local area network comprising two bus-type network devices for transmitting and receiving data, and at least two or more workstations connected to the two network devices, wherein each of the workstations includes: Two network control devices that are individually connected to network devices and that send and receive data to or from specific workstations, and two receive data memories that are connected to each of these two network control devices and store each received data individually A local area network comprising: a comparison device that compares the contents of the two received data memories; and a display device that displays the comparison result of the comparison device. 2. Each of the workstations is provided with a transmission data memory for storing the transmission to the two network devices, and the common code is added to the data received from the two network devices in the comparison device. A means for adding a code common to its own station to the network control device, and a common code determined to be a failure when the comparison device cannot detect a common code The local area network according to claim 1, further comprising means for notifying all the workstations via a network device that has normally received the message.