JPH0629996A - Communication control system - Google Patents

Abstract

(57) [Abstract] [Object] The present invention relates to a communication control system in the case of performing data communication between a plurality of communication devices, and to improve the reliability of communication between the communication devices and reduce the processing time in the event of an error. It is an object of the present invention to provide a communication control system that enables the above. [Composition] In each communication device 1, a communication control unit 10 that controls communication between the communication devices 1, a state monitoring unit 11 that monitors the states of all the communication devices 1 including the own device, and all communication control units 10. A state storage unit 12 that stores the state of the communication device 1 is provided, and the state monitoring unit 11 checks the states of all the communication devices 1 in advance and stores them in the state storage unit 12 so that the own device can communicate with other communication devices 1 The communication control unit 10 is configured to control the communication by referring to the contents of the state storage unit 12 when the data is transmitted to.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication control system for data communication between a plurality of communication devices.

[0002] In recent years, computer systems have been scaled up and integrated, while labor saving of operations has been performed. Therefore, in order to send and receive data between the respective devices, a communication means is provided to perform processing such as passing control information, and therefore high speed communication processing and high reliability communication processing are required. There is.

[0003]

2. Description of the Related Art FIG. 8 is a conceptual diagram of the configuration of a conventional system. A plurality of (n) communication devices 1 # 1 to #n are connected to the transmission line 2. A timer 1a is provided in each device. Now, for example, it is assumed that data is transferred from the # 1 communication device 1 to the #n communication device 1. A data transfer connection is established from the # 1 communication device 1 to the #n communication device 1 as shown in the figure.

When the # 1 communication device 1 notifies the #n communication device 1 of data transfer, and when the answer is returned from the #n communication device 1, the # 1 communication device 1 transfers to the #n communication device 1. Transfer data to.

If the communication device 1 of #n has a failure, the answer is not returned to the communication device 1 of # 1. #
Since the communication device 1 of No. 1 activates the built-in timer 1a at the same time as the data transfer notification, in this case, the timer 1a overflows and a time-out error occurs. When the # 1 communication device 1 detects the overflow of the timer 1a, it again notifies the #n communication device 1 of data transfer. Even if such a retry is repeated a plurality of times, if the timer 1a still has a time-out error, the communication device 1 of # 1 recognizes that the communication device of #n has a failure.

Further, when a communication failure occurs in the apparatus itself, the operator performs a process for restarting communication and cannot perform communication operation until the failure disappears.

[0007]

Therefore, in the case where communication is sequentially performed with a plurality of communication devices 1, one communication destination device is in a communication disabled state, and therefore communication with another communication device 1 is performed. Is delayed by the time-out period. In addition, when the communication itself becomes impossible, there is a problem that all communication is lost.

The present invention has been made in view of the above problems, and provides a communication control system capable of improving the reliability of communication between communication devices and shortening the processing time in the event of an error. The purpose is to do.

[0009]

FIG. 1 is a block diagram showing the principle of the present invention. The same parts as those in FIG. 8 are designated by the same reference numerals. The system shown in the figure is a system in which a plurality of communication devices 1 are connected via a transmission line 2, and a bus control device 3 connected to one end of the transmission line 2 performs competition control of the transmission line 2. Data is communicated between them.

In each communication device 1, a communication control unit 10 for controlling communication between the communication devices 1 and a state monitoring unit 11 for monitoring the states of all the communication devices 1 including the communication device 1 are all provided. A state storage unit 12 that stores the state of the communication device 1 is provided.

[0011]

When the state monitoring unit 11 checks the states of all the communication devices 1 in advance and stores them in the state storage unit 12, and the data is transmitted from the own device to the other communication devices 1, the communication control unit 10 Controls the communication by referring to the contents of the state storage unit 12. Then, the data is not transferred to the communication device 1 stored in the state storage unit 12 as incommunicable. Further, when the own device cannot communicate, the state monitoring unit 11 performs the recovery process of the own device. With such a configuration, it is possible to provide a communication control system capable of stopping data communication to a communication device having a communication failure and being able to restore communication when a failure occurs in itself. .

[0012]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 2 is a block diagram showing the configuration of the essential part of an embodiment of the present invention. The figure shows the details of the internal configuration of the communication device. The same parts as those in FIG. 1 are designated by the same reference numerals. In the figure, 10 is a communication control unit that controls communication between the communication devices 1, 11 is a state monitoring unit that monitors the state of all communication devices 1 including the own device, and 12 is a state of all communication devices 1. Is a state storage unit that stores

Reference numeral 13 is a communication device for transmitting / receiving data to / from another communication device 1 via the transmission path 2, and reference numeral 14 is a communication-related application, which is connected to the communication control unit 10.
Reference numeral 15 is a communication restoration unit that performs communication restoration processing of the own device, and starts operation when activated from the state monitoring unit 11. As the transmission path 2 to which the communication device 1 is connected, for example, TCP-
LAN using the IP protocol (local area
Network) is used. The operation of the apparatus configured as described above will be described below.

First, the state monitoring unit 11 first checks the states of all the communication devices 1 connected to the transmission path 2 via the communication device 13. Then, the status monitoring result based on the response from each communication device 1 is stored in the status storage unit 12.

When the communication control unit 10 receives a communication request from the communication-related application 14, it refers to the contents of the state storage unit 12. If the communication device 1 can transmit, it issues a communication request to the communication device 1. When a response from the partner device 1 is returned to the communication request, the response is transmitted to the communication related application 14.

If the communication control unit 10 refers to the state storage unit 12 and finds that the communication device 1 is incommunicable, it promptly notifies the communication related application 14 to that effect.

The state monitoring unit 11 reads out the state of the own device from the state storage unit 12, and when it recognizes that the own device has a failure, that is, cannot communicate with the own device, it activates the communication restoration unit 15. The communication restoration unit 15 is the state monitoring unit 1.
Upon receiving the activation from 1, the communication device 13 is reset (initialized) or IPL (initial program load) to restore itself. If the recovery fails, retry several times. When the communication is not recovered even by the retry, the communication recovery unit 15 informs the operator that the recovery is impossible through the output means (not shown).

In the above series of operations, the bus control unit 3
Performs bus contention control so that data output from each communication device 1 to the transmission path 2 does not compete.

FIG. 3 is an operation explanatory diagram of the communication control unit 10. When a communication request is received from the communication-related application 14 (), the communication control unit 10 refers to the state storage unit 12 to check whether the communication device 1 can communicate (). If communication is possible, a communication request is issued to the communication device 1 (). When the communication request from the communication device 1 is returned (), the communication request is transmitted to the communication-related application 14 side (). If, as a result of referring to the state storage unit 12, it is found that the communication partner apparatus 1 is incommunicable, a notification to that effect (error notification) is promptly issued to the communication related application 14 side ().

FIG. 4 is a diagram for explaining the operation of the status monitor 11. The state monitoring unit 11 first monitors the state of another communication device 1 via the communication device 13 (). Then, when receiving a response from another communication device 1 (), the response is analyzed and the analysis results are sequentially stored in the state storage unit 12 ().

As shown in FIG. 5, the state storage section 12 is composed of a communication device number section 12a and a state flag section 12b. The state flag 12b stores "0" when communication is possible for each communication device 1 and "1" when communication is impossible.

After the state of the series of communication devices is stored in this way, the state monitoring unit 11 looks at the state of the own device stored in the state storage unit 12 (). If the own device is in the communication disabled state, the communication restoration unit 15 is activated (). The communication restoration unit 15 includes the state monitoring unit 11
When the communication device 13 is activated, the communication device 13 is subjected to recovery processing such as initialization ().

FIG. 6 is a flowchart showing the operation of the communication control unit 10. First, communication related application 14
When the communication request command from the device is accepted (S1), the number of the communication partner device is recognized from the command (S1).
2) Read the status information of the communication device 1 in the status storage unit 12 (S3).

Whether or not the communication device 1 is communicable is checked from the status flag 12b (S4). Young
If the status flag is "0", communication is possible, so a command is issued to the communication device 13 (S5). As a result, from the TCP-IP layer of the transmission line 2 to L
The command is transmitted to the communication partner device 1 via the AN driver. Upon receiving this command, the communication partner device 1 returns a response.

The communication control unit 10 uses this communication partner device 1
When the response from is received (S6), the response is returned to the communication related application 14 (S7).

In step S4, the status flag 12b
If "1" is set to and communication is impossible, the communication control unit 10 returns a response as an error to the communication related application 14 without issuing a command from the communication device 13 (S8).

FIG. 7 is a flow chart showing the operation of the state monitoring unit 11. First, the variable I indicating the number of communication devices is set to 1
Is initially set to (S1). Next, of the communication devices connected to the LAN, those capable of communication are checked (S
2) A command for status monitoring is issued to a communication device capable of communication, and status monitoring is performed (S3). Here, by issuing a command to the incommunicable object and excluding it from the target of status monitoring, the time required for timeout can be reduced.

Next, it is checked whether the communication device 1 is communicable (S4), and the state of the communication device 1 in the state storage unit 12 is made communicable to the communicable device (S4).
5) For the incommunicable device, the state of the communication device 1 in the state storage unit 12 is set to be incommunicable (S6). That is, the state flag 12b is set to "0" for the communicable device, and the state flag 12b is set to "1" for the incommunicable device.

The variable I is updated by 1 (S7). next,
It is checked whether the variable I exceeds the number n of communication devices (S8). If I does not exceed n, step S
Return to 2 and repeat the same operation. When I exceeds n, it means that the status check is completed for all the communication devices 1 that can communicate.

This time, the state of the own device is taken out from the state storage unit 12 and it is checked whether communication is impossible (S).
9). If the own device can communicate, the process returns to step S1 and the state check is repeated at regular intervals. If the own device cannot communicate, the communication restoration unit 15 is called to perform communication restoration processing (S10).

It is checked whether or not the communication restoration is successful (S11), and if successful, the communication is notified to all communication devices 1 (S12), and the step S
Return to 1. If the communication recovery fails, it is checked whether or not the recovery process is repeated a preset number of times (K times) (S13). If the recovery process is not repeated after K times, the process ends with an error (S14). ). In this way
According to the present invention, it becomes possible to update the state of each communication device stored in the state storage unit 12 and control communication using the state.

[0033]

As described above in detail, according to the present invention, the state of each communication device is checked in advance, the state is stored in the storage unit in the own device, and this storage unit is used for communication. The communication is controlled by the information of the communication device and the recovery processing is performed when the communication failure occurs in the own device, thereby improving the reliability of communication between the communication devices and shortening the processing time in the case of an error. It is possible to provide a communication control system capable of performing the above.

[Brief description of drawings]

FIG. 1 is a principle block diagram of the present invention.

FIG. 2 is a configuration block diagram showing a main part of an embodiment of the present invention.

FIG. 3 is an operation explanatory diagram of a communication control unit.

FIG. 4 is an operation explanatory diagram of a state monitoring unit.

FIG. 5 is a diagram showing a configuration example of a state storage unit.

FIG. 6 is a flowchart showing an operation of a communication control unit.

FIG. 7 is a flowchart showing an operation of a state monitoring unit.

FIG. 8 is a conceptual diagram of a configuration of a conventional system.

[Explanation of symbols]

 1 Communication Device 2 Transmission Line 3 Bus Control Unit 10 Communication Control Unit 11 State Monitoring Unit 12 State Storage Unit

Claims (2)

[Claims] 1. A plurality of communication devices (1) are connected via a transmission line (2), and a competition control of the transmission line (2) is performed by a bus controller (3) connected to one end of the transmission line (2). In the system for performing data communication between the communication devices (1), a communication control unit (10) for controlling communication between the communication devices (1) and A state monitoring unit (11) that monitors the states of all communication devices (1) including devices, and a state storage unit (1) that stores the states of all communication devices (1).
2) is provided, and the state monitoring unit (11) checks the states of all the communication devices (1) in advance and stores them in the state storage unit (12). The communication control system (10) is configured to control the communication by referring to the contents of the state storage unit (12) when transmitting. 2. A communication restoration unit (15) for restoring communication of the own device is provided in the communication device (1), and the state monitoring unit (11) refers to the contents of the state storage unit (12). The communication control system according to claim 1, wherein when the communication failure of the own device is found, the communication recovery unit (15) is activated to perform the recovery process of the own device.