JPH0662085A - Communication control device - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] For n types of protocol processing communication control devices,
The function of logically disconnecting only the faulty line control unit can be realized by adding only one new module, the availability is improved by a slight modification of the existing device, and the development cost of the communication control device is kept low. . [Structure] The line monitoring unit 12 is a mechanism for monitoring a failure of the line control unit 11 and insertion / removal of the line control unit interface unit 121, command / response monitor 122, and the like.
The line control unit 11 includes a line state holding table 123 that holds the type and state of the line control unit 11 and an abnormal response search table 124 that holds a response that simulates a line fault for each type of the line control unit 11 and command type. . When the failure / removal state of the line control unit 11 is recognized, the common control unit 13 and the higher-level processing device 3 recognize the line failure based on the type information of the line control unit and the information held in the abnormal response search table 124. The common control unit 13 is notified of the response.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication control device for realizing data transfer with a plurality of terminal devices connected via a plurality of communication lines, and particularly to a communication control device having a configuration suitable for suppressing development costs. Regarding the device.

[0002]

2. Description of the Related Art In general, a communication control device for realizing data transfer with a plurality of terminal devices connected via a plurality of communication lines is provided for each line and performs serial / parallel conversion, signal line change monitoring, and the like. It is realized by a line control unit for performing and a common control unit for controlling a plurality of line control units and performing a plurality of types of protocol processing. In the communication control device having such a configuration, even if a failure occurs only in the line control unit corresponding to the specific line, if the failure relates to the shared resources of the entire device, the control of other lines cannot be continued. It becomes a big problem. This problem has been circumvented by making the common control unit have a mechanism for recognizing a failure of an individual line control unit and logically disconnecting the line control unit when newly developing the device. When remodeling the device utilizing the above, the common control unit is configured with multiple modules corresponding to the protocol types in order to realize multiple types of protocol processing, and therefore the faulty line control unit is logically configured. Remodeling to have a mechanism to cut off extends to multiple modules. Incidentally, as for the device of this type, for example, Japanese Patent Application Laid-Open No. 61-1085.
81 is mentioned.

[0003]

In the above-mentioned prior art, in the case where a mechanism for logically disconnecting the faulty line control unit is provided by utilizing existing assets, the number of man-hours is large because the remodeling involves a plurality of modules, and the device is large. It was a factor that increased the price. The object of the present invention is to improve such problems,
It is an object of the present invention to provide a communication control device suitable for modification so that processing of another line can be continued even when a line control unit corresponding to an individual line fails without increasing the device price.

[0004]

In order to achieve the above object, a communication control device of the present invention is provided for each line, and a line control unit having a function including serial-parallel conversion and signal line change monitoring, and A common control unit that implements processing including protocol processing by issuing commands and receiving responses to the line control unit and a common control unit that is arranged between them and monitors the line control unit for failure and insertion / removal, It is characterized in that it has a line monitoring means (line monitoring unit) that returns a response simulating a line failure in the line under the line control unit when the line control unit fails or when an illegal package is inserted / removed. . This line monitoring means is, for example, a mechanism for monitoring the line control unit for failure and insertion / removal monitoring (a line control unit interface unit, a command / response monitor), and a line state for holding the type and state of the line control unit. It is composed of a holding table, an abnormal response search table for holding a response that simulates a line failure for each type of line control unit and type of command.

[0005]

In the present invention, normally, the common control unit issues commands to a plurality of line control units and monitors responses through the line monitoring unit to realize communication control of a plurality of lines. When the monitoring unit recognizes a failure of the line control unit, the command from the common control unit for the line control unit corresponding to the particular line and the response from the line control unit are cut off, and the command of the common control unit is cut off. When the issue is triggered, the common control unit and the upper processing unit return a response that appears as if a line failure had occurred, so when the line control unit corresponding to a specific line fails or is removed, the effect of the failure or removal It is possible to continuously control the other lines by avoiding the transmission to the shared resources of the entire device. In this way, even when an individual line fails or is removed, recovery by the line failure handling function is possible, and the continuity of control of other lines at this time can be maintained. That is, n
When a communication control device that realizes a kind of protocol processing has a function of logically disconnecting only the line control unit in which a failure has occurred, it can be realized by adding only one new module. The availability can be greatly improved by various modifications. Therefore, the development cost of the device can be kept low.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a communication system according to an embodiment of the present invention. In FIG. 1, the communication control device 1 is connected to a plurality of line termination devices 2 and a host processing device 3. The communication control device 1 also includes a plurality of line control units 11,
It has a line monitoring unit 12 and a common control unit 13.

FIG. 2 is a block diagram showing details of the line monitoring unit shown in FIG. In FIG. 2, the line-to-line control unit interface unit 121 distributes a command to a plurality of line control units 11 and transmits a response from the line control unit 11 to the common control unit 13. Further, the command / response monitor 122 has a function of monitoring and format-checking the command and response to detect a failure of the line control unit 11, and stopping command distribution / response transmission to the line control unit 11 in which a failure has occurred. It has a function of instructing the on-line control unit interface unit 121. The line state holding table 123 is a table for holding the type (line control unit type) and state (normal operation / abnormal / uninstalled) of the line control unit 11 corresponding to each line, as shown in FIG. is there. Further, the abnormal response search table 124 shows, in FIG. 4, a response that the common control unit 13 and the higher-level processing device 3 recognize as a line fault when the common control unit 13 issues a command to the faulty line control unit. As shown, this is a table held for each type of line control unit 11 and each type of command. Note that FIG.
The line control unit type shown in (1) corresponds to the line control unit type shown in FIG.

Next, the communication control method of the system of this embodiment will be described. FIG. 5 is a sequence diagram showing a communication control method in the embodiment of the present invention. In this embodiment,
When the line control unit 11 is normal, the line monitoring unit 12 distributes / transmits commands and responses as they are,
When the fault / removal state of the line control unit 11 is recognized,
The command from the common control unit 13 for the line control unit and the response from the line control unit are cut off,
The common control unit 13 is notified of the response from the information indicating the type of the line control unit and the information stored in the abnormal response search table 124. For example, when an incorrect response is returned from the line control unit of type "A" (line control unit type A) after the transmission start command is sent, the line monitoring unit 12 recognizes the occurrence of a failure and stores the line state holding table. The line status of 123 is updated to "abnormal", and the response search table 124 at the time of abnormality is received in response to the "start transmission data CRC calculation" command from the common control unit 13.
"CS line off" is returned by referring to the part corresponding to the type. For this pseudo response, the common control unit 13
Sends a "forced stop" command but does not send a response. After that, when the package is removed by the line control unit, the line monitoring unit 12 detects this and updates the line state of the line state holding table 123 to "not mounted". In addition, in response to the “start transmission” command from the common control unit 13, “CS line off” is returned as in the above, and the common control unit 13 sends a “transmission forced stop” command. After that, when a normal package is inserted in the line control unit, the line monitoring unit 12 detects this, updates the line state of the line state holding table 123 to “normal operation”, and the common control unit 13 The “start transmission” command is transmitted to the line control unit. In this way, even when the individual line control unit 11 fails or is removed, recovery can be performed by the line failure handling function, and the continuity of control of other lines can be maintained.

[0009]

According to the present invention, when the communication control device realizes n kinds of protocol processing, it can be realized by adding only one new module, and the conventional common control unit can be modified (n Availability can be improved significantly with a slight modification to existing equipment. Therefore, the development cost of the communication control device can be suppressed.

[0010]

[Brief description of drawings]

FIG. 1 is a block diagram of a communication system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing details of a line monitoring unit in an embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a line state holding table according to an embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of an abnormal response search table according to an embodiment of the present invention.

FIG. 5 is a sequence diagram showing a communication control method according to an embodiment of the present invention.

[Explanation of symbols]

 1 Communication Control Device 2 Line Termination Device 3 Upper Processing Device 11 Line Control Unit 12 Line Monitoring Unit 13 Common Control Unit 121 Line Control Unit Interface Unit 122 Command / Response Monitor 123 Line State Holding Table 124 Abnormal Response Search Table

Claims (1)

[Claims] 1. A line control unit provided for each line and having a function including serial-parallel conversion and signal line change monitoring, and a protocol by issuing a command and receiving a response to the line control unit. In a communication control device provided with a common control unit for realizing processing including processing, the line control unit is located between the line control unit and the common control unit, and monitors the line control unit for failure and insertion / removal. The communication control device is provided with a line monitoring means having a mechanism for returning a response simulating a line failure in a line under the line control unit at the time of the failure, when the illegal package is inserted, and when the illegal package is removed.