JPH10145459A - Communication system for guaranteeing data integrity - Google Patents

Abstract

PROBLEM TO BE SOLVED: To guarantee data integrity by redundantly constituting an element, where a data buffer for data transmission exists, and reproducing the control information of buffer for data communication from information for controlling an adjacent buffer for data transmission on a data communication path in case of switching from active system to reserve system. SOLUTION: When a CPU 110 detects the generation of any abnormality at a communication interface part 130 of active system, this interface part 130 is disconnected from a computer bus 170 of a host computer 100, and the request of switching to the active system is outputted to a communication interface part 230 of reserve system. Then, information lost by this switching is reproduced from a main memory 120 and a line control module 160. Thus, without mutually confirming a data communication state before fault generation between a terminal and the host computer, data integrity can be guaranteed concerning data in both the direction of transmission from host computer to terminal and reception from terminal to host computer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission system from a host computer to a communication line of an information service system for transmitting information from a host computer in real time, and in particular, hardware for controlling communication of the host computer. The present invention relates to a data integrity assurance method which is multiplexed and is suitable when they are operated in a working system and a standby system.

[0002]

2. Description of the Related Art Conventionally, a method of guaranteeing continuity of output data when switching from a working system to a standby system in a dual system is disclosed in Japanese Patent Laid-Open No. 63-33939.
Manual switching from the active system to the standby system is performed, and prior to the system switching performed as an opportunity, data (reception data, transmission data, transmission standby address, etc.) for performing an inter-system link is transferred from the active system to the standby system. After the completion of the data transfer, the system is switched. In this way, when switching systems,
The continuity of the output data is guaranteed by transferring the information of the transmission data from the active system to the standby system.

[0003]

The above-mentioned prior art is a method which is effective only when the switching from the active system to the standby system is performed manually. When a failure occurs in the active system, the inter-system link is always established. There is a problem that the information to be performed cannot always be transferred to the standby system, and a failure occurs in the active system, so that it cannot be applied when switching the system.

Further, the above-mentioned prior art is for guaranteeing the continuity of data transmission from the host computer to the terminal, and it is considered that the continuity of data transmission from the terminal to the host computer is guaranteed. No
Even if the inside of the host computer is duplicated and a failure occurs in one system, there is a problem that the data transmitted from the user of the terminal is lost even though the system can be operated. .

SUMMARY OF THE INVENTION It is an object of the present invention to provide a communication system mainly including a host computer. Also, if the data communication state before the failure occurs is not mutually confirmed between the terminal and the host computer, the data can be transmitted from the host computer to the terminal and from the terminal to the host computer in both directions. To ensure data integrity.

A second object of the present invention is to provide both a one-to-one communication between a host computer and a terminal and a data communication system in which a multicast communication service for simultaneously transmitting data from a host computer to a plurality of terminals is mixed. Data integrity can be guaranteed.

[0007] A third object of the present invention is to guarantee data integrity when a failure occurs in an active system and the system is switched to a standby system and communication is continued as a new active system.
An object of the present invention is to minimize data to be retransmitted from other parts for the new working system.

A fourth object of the present invention is to reduce the number of communications between a CPU and a communication interface unit for controlling a communication buffer held in a main memory in order to guarantee data integrity. An object is to reduce overhead for buffer control.

[0009]

In order to solve the first and third objects, the following means are used in a host computer of a communication system and a multi-line control device. That is,
CPU of host computer, communication interface unit,
The following means are provided in each of the line control modules of the multi-line control device.

(1) Means for controlling the order of transmission and reception data in units of transmission on a data transmission path.

(2) Means for detecting how many packets of the minimum unit (packet) of the data stored in the communication buffer are data.

(3) Means for storing the total number of packets transmitted or received by the packet number continuously attached to the transmitted or received packets.

(4) Means for holding the data received from the upstream side of the data transmission path in the communication buffer even after transmitting the data to the downstream side.

(5) means for receiving a transmission completion notification of the data transmitted from the downstream side of the data transmission path to the downstream side, and reporting the transmission completion notification to the upstream side having received the data.

(6) Means for releasing the data held in the communication buffer upon receipt of the transmission completion notification from the downstream side.

The following means are provided in the line control module.

(7) A means for, when detecting that a failure has occurred in the communication interface unit, suppressing transmission to the communication interface unit until receiving a communication enable notification from the communication interface unit.

(8) A means for receiving only a specific command from the communication interface unit in response to an instruction from the communication interface unit.

Further, the following means are provided in the communication interface unit.

(9) Means for notifying to the line control module that communication preparation is underway when switching from the active system to the standby system.

(10) When switching from the active system to the standby system, a request is made to the individual line control modules to transmit information on data packets held in the communication buffers of the individual line control modules. Means to do.

(11) For the above line control module,
When communication becomes possible after switching from the active system to the standby system,
Means for notifying the communication interface unit that transmission is possible.

(12) Means for receiving, from the CPU, information on the data packet held in the communication buffer of the CPU when switching from the active system to the standby system.

(13) A means for newly regenerating information on the data packet for the communication interface unit from information on the data packet collected from the CPU and the line control module when switching from the active system to the standby system.

(14) As a result of reproducing the information on the data packet for the communication interface unit, a packet number for which the line control module has received the transmission completion notification,
If the packet number of the transmission completion notification received by the CPU is different, the communication interface unit determines that the transmission completion notification has been received by the communication interface unit up to the packet number of the transmission completion notification received by the line control module. Means for reporting the transmission completion notice to the CPU after the restart, for the different packet numbers for which the transmission completion notice has been received between the CPU and the line control module.

(15) When the system is switched from the active system to the standby system, based on the information obtained by the means for reproducing the information on the data packet for the communication interface, the data held in the communication buffer of the communication interface unit is converted into the data described above. Means for designating a packet number and requesting the CPU to retransmit.

The CPU is provided with the following means.

(16) Means for transmitting information on data packets held in the communication buffer of the CPU to the communication interface unit when the communication interface unit is switched from the active system to the standby system.

(17) Means for retransmitting the data of the packet number requested to be retransmitted from the communication interface unit to the communication interface unit.

The following means are used to solve the second object. That is, the CPU is provided with the following means.

(1) Multicast transmission means for transmitting the same data to a plurality of lines.

The following means are provided in the CPU and the communication interface unit.

(2) data for multicast transmission;
Distinguish data for one-to-one transmission between CPU and terminal,
A means for independently assigning and managing sequence numbers.

(3) Means for storing destinations of multicast transmission, and holding the data for multicast in a communication buffer until data transmission completion notices are received from all the destinations.

Further, the following means are provided in the line control module.

(4) Whether the data packet received from the communication interface is a result of multicast transmission
A means for identifying and storing whether or not the transmission is one-to-one.

The following means is used to solve the fourth object. That is, the following means are provided in the communication interface unit.

(1) Means for dividing data transmitted from the CPU into packets to be transmitted to the line.

(2) means for assigning a sequence number to the divided packets.

(3) Means for storing the data name of the data transmitted from the CPU in association with the final sequence number assigned to the packet obtained by dividing the data.

(4) Means for compiling the transmission completion notification received from the line control module in packet units into the data unit transmitted from the CPU.

[0042]

The means for the above purpose operates as follows.

(1) Data transmission to terminal When transferring data from the host computer to the terminal, first, the CPU detects how many packets of data to be transferred, and transmits the sequence number of the transmission data for each line. Advance by the number of packets. It is stored as the latest transmission packet number. Thereafter, the CPU notifies the communication interface unit of the host computer of the occurrence of the data transmission request. The communication interface unit that has detected the data transmission request from the CPU reads data from the main memory into a communication buffer provided inside the communication interface unit and stores the data. At this time, the data is held without releasing the communication buffer of the main memory. The communication interface unit notifies the line control module of the multi-line control device connected to the communication interface unit that controls the line for which transmission has been requested that a transmission request has been generated for each packet. At this time, the packet number of the last packet transmitted to the line is stored for each line. Upon detecting a data transmission request from the communication interface unit, the line control module reads data from a communication buffer of the communication interface unit and stores the data in a communication buffer provided in the line control module. And
The line control module updates the packet number of the last packet transmitted to the line each time data of one packet is transmitted. Here, when the data transfer from the communication buffer of the communication interface unit to the communication buffer of the line control module is completed, the line control module notifies the communication interface unit of the completion of data transmission. Upon receiving the transmission completion notification, the communication interface unit releases the communication buffer storing the data confirming the transmission completion. The line control module releases the data stored in the communication buffer of the line control module when receiving a transmission completion confirmation notification from the terminal for the data transmitted to the line. Then, the communication interface unit is notified of the reception of the transmission completion confirmation notification from the terminal. Upon receiving the transmission completion confirmation notice, the communication interface unit determines whether transmission completion confirmation notices for the number of packets received from the CPU have been received, and transmits the transmission completion confirmation notices for the number of received packets to the line. If received from the control module, the CPU notifies the CPU of a transmission completion confirmation. When the CPU receives the transmission completion confirmation notification from the communication interface unit, the CPU releases the communication buffer in the main storage holding the transmission completed data.

(2) Receiving Data from Terminal When the line control module of the multi-line controller receives data from the terminal, it updates the received packet number and stores the received data in the communication buffer on the line control module. . Then, the communication interface unit of the host computer is notified of data reception from the terminal. Upon detecting data reception from the terminal, the communication interface reads the received data from the communication buffer of the line control module into the communication buffer on the communication interface. Then, the received packet number managed by the communication interface unit is updated. Then, for the CPU,
Notifies that data has been received from the terminal. When detecting data reception from the terminal, the CPU reads the received data from the communication buffer of the communication interface unit to the communication buffer on the main memory. Then, the received packet number managed by the CPU is updated. Then, in the CPU,
A transmission completion confirmation is notified to the communication interface unit. When the transmission completion confirmation is detected by the communication interface unit, the data for which the transmission completion confirmation has been received is released from the communication buffer. Then, the communication completion confirmation is notified to the line control module. Upon detecting the transmission completion notification, the line control unit releases the one storing the corresponding data in the internal communication buffer.

(3) Operation when an error occurs in the communication interface unit When an error occurs in the communication interface unit of the host computer, the CPU detects the abnormality and switches the communication interface unit from the active system to the standby system. At this time, the communication interface unit that has newly changed from the standby system to the active system notifies the line control module of the multi-circuit controller that communication restart is being prepared in the new active system. In the line control module, when an attempt to communicate with the communication interface unit is detected, when the occurrence of a communication error is detected, the communication interface unit switches to a new active system and the communication control unit waits until it notifies that communication can be resumed. The state is switched so as to suppress communication with the communication interface unit. When the communication interface unit is switched to the new active system, the newly active communication interface unit transmits to the CPU information on the data packet in the communication buffer on the main memory managed by the CPU. Request to do so. Thereafter, each line control module is requested to transmit information on the data packet in the communication buffer of the line control module. Then, the data relating to the data packet in the communication buffer of both the CPU and the line control module are matched, and the information lost by switching the communication interface unit is reproduced. As a result of the information reproduction, when it is necessary to retransmit the data again from the main memory, the packet number to be retransmitted is designated and the CPU requests the CPU to retransmit the data. The CPU retransmits the data of the packet number requested to be retransmitted from the communication buffer on the main memory. In this way, when the communication can be restarted, the communication interface unit notifies each of the line control modules that the communication can be performed. In this manner, even when the line control module attempts to communicate with the communication interface unit during the switching process of the communication interface unit,
Waiting for the end of the switching operation enables communication.

[0046]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 shows a schematic configuration of a communication system according to an embodiment of the present invention and an internal structure of the host computer 100 and the multi-line control device 140 on the host side. The communication system includes a host side (data server side) including a host computer 100 and a multi-line control device 140, and a terminal 290 connected to the host side via a network 285.
(The data client side), a plurality of multi-line controllers 140 are connected to one host computer 100, and a plurality of lines 180 are connected to one multi-line controller 140.
(Terminal 290). The host computer 100 is C
Internal components such as the PU 110 (210), the main memory 120 (220), the communication interface unit 130 (230), and the computer bus 170 (270) are duplicated, and a failure occurs in one of the duplicated components. It is a fault-tolerant computer that can continue normal operation even if it occurs. In addition, the multi-line control device 140 is connected to the communication interface unit 130 of the host computer 100 via the interface cable 190 and the computer interface module 150, and has a one-to-one correspondence with the duplexed communication interface unit 130. And a computer interface module 150. The inside of the multi-line control device 140 is configured such that the computer interface module 150 and the line control module 160 are connected to the internal bus 155 of the multi-line control device by a bus. Then, the line control module 160 controls one or a plurality of lines 180, and via the line 180 and the network 285, the line control module 160
Connected to terminal 290. Also, the host computer 100
In the internal communication interface unit, one communication interface unit 130 operates as an active system, and the other communication interface unit 230 operates as a standby system. Therefore, the computer interface module 150 in the multi-line control device 140 also operates separately for the active system and the standby system corresponding to the communication interface unit 130. That is, the multi-line control device 14
The internal bus 155 of 0 can be accessed only by the active system 150 among the two computer interface modules. Here, if the active communication interface unit 130 fails and is switched to the standby communication interface unit 230, the computer interface module is also switched to the active communication interface unit 230.
It switches from 0 to the standby system 250. Similarly, the current system of the computer interface module of the multi-line controller
When a failure occurs in 150, both the communication interface unit and the computer interface module are switched from the active system to the standby system. The line control module 160 and the terminal 290 support up to a data link level protocol of data communication (layer 2 of the OSI seven-layer protocol model). Layer 3 or higher protocol between the terminal and the host side, on the host side,
It is controlled by a program operating on the CPU 110. When data is transmitted from the communication interface unit 130 to the main memory 120, the same data is transmitted to both main memories that are duplicated via the duplicated computer bus 170.

FIG. 1 shows an internal configuration of a host in a communication system according to an embodiment of the present invention. On the host side, the transmission packet number and the reception packet number,
The main memory 120, the communication interface unit 130, and the line control module 160 are provided with a data communication management table for managing the empty state of the communication buffer managed by each unit. The data communication management table 121 has a transmission packet number 122, a transmission data free buffer number 123, a reception packet number 124, and a reception data free buffer number 125 as constituent elements. C
By the program operating on the PU 110, the data communication management table 131 on the communication interface unit 130 stores the microprocessor 136 controlling the communication interface unit.
Line control module 16
The data communication management table 161 on 0 is operated by a program operating on the microprocessor 166 controlling the line control module.

FIG. 3 is a block diagram showing the internal configuration of a program operating on the microprocessor 136 of the communication interface unit 130. The program can be roughly divided into a process for data communication control, a process for thread switching, a self-diagnosis process other than the above, and a monitoring process for a multi-line control device. The processing for data communication control is performed by a CPU that controls communication with the CPU 110.
There are a communication process 320, a multi-line control device communication process 340 for controlling communication with the multi-line control device 140, and a data communication process 310 for performing packet division and order control. The operation of the data communication table 131 is performed in the data communication processing 310.
The data communication process 310 further assigns a sequence number to each of the transmission packet and the reception packet, and stores the latest transmission / reception packet number.
The process is divided into a buffer space management process 310-b for managing the space in the transmission / reception data buffer. Active system switching processing 330
The communication interface unit which has newly become the active system instructs the line control module 160 of the multi-line control device 140 to suppress data transmission and reproduces the information lost due to the switching. To send packet control information. In the diagnosis and monitoring process 350, the status of the communication interface unit 130 and all the modules of the connected multi-line control device 140 are monitored, and when an error is detected, the CPU 110 is notified of the error occurrence portion.

FIG. 4 is a block diagram showing the internal configuration of a program operating on the microprocessor 166 of the line control module 160. The program includes data communication processing 410, bus interface processing 420,
It comprises a line control process 430 and a configuration control process 440.
Data communication management table 161 on line control module 160
Is the packet number management process 410 of the data communication process 410
-a and buffer empty management processing 410-b. And
In the bus interface process 420, communication control with the communication interface unit 130 is performed. Also, the line control processing 430
Performs data link level protocol control (for example, HDLC) with the terminal via the line 180, and notifies the data communication process 410 of the result of data transmission to the line and data reception from the line. Then, in the configuration control process 440, recognition of the occurrence of a failure in the communication interface unit or the computer interface module 150, processing at the time of failure, and processing for stopping and restarting data communication related thereto are performed.

Hereinafter, the flow of processing in the communication interface unit 130 and the line control module 160 during data transmission / reception will be described with reference to FIGS.

FIG. 5 shows a data communication table of the communication interface unit 130 at the time of data transmission and a flow of processing mainly on control of the communication buffer.
When the editing of the data to be transmitted to the terminal by the program running on the CPU 110 is completed, the communication buffer 127 on the main memory 120 is acquired for the transmission data. Then, the transmission packet number 122 of the data communication management table 121 is updated, and the data is transferred to the communication interface unit 130. At this time,
A transmission packet number corresponding to the data is added as additional information of the transfer data. In the communication interface unit 130,
The data transmission request from the CPU 110 is transmitted to the CP operating on the microprocessor 136 of the communication interface unit 130.
Accepted in the U communication processing 320 (step 500), the buffer empty management processing 310-b also operating on the microprocessor 136 of the communication interface unit 130 operates and checks the empty of the buffer 137 (501). , C
The PU 110 is notified that transmission data cannot be received (502). If not, a necessary amount of buffer is acquired (503). Then, data is transferred from the main memory 120 into the acquired buffer (504). When the data transfer is completed, the packet number management processing 310-a updates the transmission packet number 132 of the data communication management table 131 to the packet number received from the CPU 110 as the latest information (505). Then, the data is transmitted to the multi-line control device communication processing 340. Then, the multi-line control device communication processing 340 issues a packet transmission request to the line control module 160 of the multi-line control device 140 (506). As a result of receiving a response from the line control module 160 to the transmission request (507), if the line control module 160 cannot accept data, the process waits until data can be accepted. If the request can be accepted, the data is transmitted to the line control module 160 (508). Then, it waits for a data reception confirmation notification from the terminal from the line control module 160 (50).
9). When the data reception confirmation notification from the terminal is received from the line control module 160 in the multi-line control device communication processing 340, it is notified to the packet number management processing 310-a.
In the packet number management process 310-a, the transmission confirmation packet number 133 in the data communication management table 131 is updated to the latest one (510). Then, the buffer empty management processing 310-b
Then, it is checked whether or not there is a transmission confirmation packet number after the update and a packet number registered as additional information of the buffer waiting to be released. If there is an equal packet, the buffer having the same packet number is released (511), and a transmission completion confirmation notice of the packets up to the transmission confirmation packet number 133 in the communication management table 131 is sent to the CPU 110 (512). CPU 11
When the packet transmission completion confirmation notice is received at 0,
The packet number is updated to the notified number in the transmission confirmation packet number 123 of the data communication management table 121 in the main memory 120, and then the buffer corresponding to the packet number is released.

FIG. 6 shows the flow of data transmission processing in the line control module. When the bus interface processing 420 operating on the microprocessor 166 of the line control module 160 receives the data transmission request from the communication interface unit 130 transmitted in step 506 of FIG. 5 (step 600), the buffer empty management processing The free state of the communication buffer 167 is checked in step 410-a (601).
Is notified that transmission data cannot be received (60
2). If an area where data can be received from the communication interface unit 130 is free, a communication buffer is acquired (60).
3). Then, in the packet management process 410-b, the transmission packet number in the data communication management table 161 is updated.
(604). Then, the packet is transmitted to the line control process 430.
To send to. The line controller 430 transmits the received packet to the terminal via the line 180 (605). Then, the line control processing 430 waits for the reception of the acknowledgment of the transmission packet at the data link level of the terminal (60).
6). Then, upon receiving the reception confirmation at the data link level of the terminal, the line control process 430 notifies the packet number management process 410-b. In the packet number management process 410-b, the transmission confirmation packet number 163 in the data communication management table 161 is updated by the number of which the terminal has confirmed the reception (60).
7). Then, the buffer free space management process 410-a releases the buffer in the area occupied by the updated transmission confirmation packet number (608). After that, it requests the bus interface processing 420 to notify the communication interface unit 130 that the data reception confirmation of the packet number corresponding to the released buffer has been received from the terminal (60).
9) Notify the communication interface of data transmission confirmation.

In this way, the host computer 100
It performs packet number order control and buffer management when transmitting data from the terminal to the terminal and receiving data reception confirmation from the terminal.

FIG. 7 shows the flow of processing in the line control module 160 when receiving data. When data is received from the terminal in the line control processing 430 of the line control module 160 (700), the buffer empty management processing 410-a
Acquires a buffer (701) and stores the received data. Then, the line control process 430 notifies the packet number management process 410-b of the data reception. In the packet number management processing 410-b, the received packet number 164 of the data communication management table 161 is updated (702). Thereafter, the bus interface processing unit 420 is requested to notify the communication interface unit 130 that data has been received from the terminal (703). It waits for a response from the communication interface unit 130 in response to the data reception notification (704). If data cannot be received, it waits until data can be received. When data can be received, the communication interface unit 13
Wait for 0 to read the data and notify the line control module 160 of the data reception confirmation (705). When the data reception confirmation is received, the packet number management processing 41
In 0-b, the acknowledgment packet number 165 of the data communication management table 161 is updated (706). Then, the buffer empty management process 410-a releases the buffer in the area occupied by the updated acknowledgment packet number (70).
7).

FIG. 8 shows a flow of a process performed by the communication interface unit 130 when receiving data. When the data reception notification from the terminal is received from the line control module 160 in the multi-line control device communication processing 340 (80)
0), the buffer free space management process 310-b checks the free space of the buffer 137 (801), and if there is no free space, notifies the line control module 160 that the received data cannot be received (802). If it is free, a required amount of buffer is acquired (803). Then, data is transferred from the line control module 160 into the acquired buffer (80).
4). When data transfer is completed, packet number management processing
310-a updates the received packet number 134 of the data communication management table 131 to the packet number received from the line control module 160 as the latest information (805). And
It is sent to the CPU communication processing 320. Then, the CPU communication processing 320 issues a transmission request for data reception to the CPU 110 (806). As a result of receiving the response from the CPU 110 to the reception request (807), if the CPU 110 cannot accept the data, it waits until the data can be accepted.
If acceptable, the data is transmitted to CPU 110 (808). Then, it waits for a data reception confirmation notification from the CPU 110 (809). When receiving the data reception confirmation notification from the CPU 110 in the CPU communication processing 320, it notifies the packet number management processing 310-a of the reception. In the packet number management process 310-a, the reception confirmation packet number 135 of the data communication management table 131 is updated to the latest one (810). Then, in the buffer free space management process 310-b, it is checked whether or not there is a packet number which is equal to the updated reception confirmation packet number and the packet number registered as accessory information of the buffer waiting to be released. If they are equal, the buffer having the same packet number is released (811), and a reception completion confirmation notice of the packets up to the reception confirmation packet number 135 in the communication management table 131 is sent to the line control module 160 (812). ).

Next, processing performed to guarantee the continuity of data when an error occurs and the communication interface unit 130 is switched will be described with reference to FIGS.

FIG. 9 shows an active communication interface unit 13.
0 or computer interface module 150
2 shows the operation when the CPU 110 and the line control module 160 respectively detect that an error has occurred. The CPU 110 detects the occurrence of a data communication abnormality with the communication interface unit 130, or the communication interface unit 130 itself or the computer that detects the result of the self-diagnosis or the monitoring process of the multi-line control device 140 from the communication interface unit 130. Interface module 150
When the notification of the occurrence of the abnormality is received, the state firstly shifts to a state in which transmission to the part where the abnormality has occurred is suppressed except for the one necessary for switching, and the part where the abnormality has occurred is separated from the communication system. If the communication interface unit 130 is abnormal, the abnormal communication interface unit 130 is disconnected from the computer bus 170 of the host computer 100. When an abnormality occurs in the computer interface module 150 of the multi-line control device 140, the communication interface unit 130 is instructed to disconnect the computer interface module 150. Thereafter, the CPU 110 issues a switching request to the communication interface unit 230 of the standby system so as to newly become the active system. In the communication interface unit 230 of the standby system,
Upon receiving a request to switch to the active system from the CPU 110, the communication interface unit newly switches to all the line control modules 160 of the multi-line control device 140 via the computer interface module 250 to become the active system. Notify that it is inside. In the line control module 160 that has received the notification that the communication interface unit is being switched, information necessary for switching the communication interface unit 230 is received until a communication restart notification is received from the newly active communication interface unit 230. Except for transmitting necessary data to the communication interface unit 230 in response to a command to request transfer, the communication interface unit 230 is configured to be in a communication interface unit switching waiting state for suppressing communication with the communication interface unit 230. In the control process 440, the communication state is controlled. Further, when the occurrence of a communication error is detected by the data communication process 410 when transmitting data to the communication interface unit 130 by the line control module 160, the occurrence of a communication error is notified to the configuration control process 440 of the line control module 160. In the configuration control process 440, however, it is considered that an error has occurred in any part between the communication interface unit 130 and the line control module 160, and the communication state is set to a computer communication path error occurrence state. Then, after storing the processing at the time of occurrence of the abnormality, the communication interface unit waits for switching.

FIG. 10 shows the state of the CPU 110 after switching the communication interface unit to a new active system until communication is resumed.
FIG. 11 shows an outline of processing in the communication interface unit 230. FIG. 11 shows a flow of internal processing in the communication interface unit 230 which has newly become the active system. When the communication interface unit is switched to the new active communication interface unit 230 (step 110)
0), first, in the communication interface unit 230, if an error occurs in the communication interface unit 130 in accordance with the portion where the error has occurred, the switched communication interface unit 230
For all line control modules under the control of
If an abnormality occurs in the computer interface module 150 of the multi-line control device 140, the multi-line control device 1 to which the computer interface module 150 belongs
For all the 40 line control modules, the CPU 110 and the line control module 160 are requested to transmit packet control information in order to check how much data transmission / reception has been completed in each line control module (1101, 1102). ). When the packet control information transmission request from the communication interface unit 230 is received by the line control module 160, the data communication management tables 161 of all the lines managed by the line control module 160
Is transmitted to the communication interface unit 230 via the communication interface unit 260. The CPU 110 transmits the contents of the communication management table 121 managed on the main memory 120. When packet control information is received from the line control module 160 and the CPU 110, the respective contents are compared and compared (1103). As a result of the comparison, the CPU
The line in which the data transmission / reception status recognized by 110 and the data transmission / reception status of the line control module 160 are the same is managed in the main memory 120 in the data communication management table 231 of the communication interface unit 230 which has newly become the active system. The same contents as the data communication management table 121 are set (1).
104). Then, the transmission packet number 122 of the data communication management table 121 is compared with the transmission confirmation packet number 123 (1105), and if they are different, the packet between the packet number following the transmission confirmation packet number and the transmission packet number Is retransmitted to the communication interface unit 230 (1106). If they are equal, no data transfer is performed. Then, it is checked whether or not the matching check has been completed for all the lines (1107), and if it has been completed, the completion of switching is notified to the CPU 110 (11).
08). If the matching check has not been completed for all the lines, the processing from step 1103 is repeated. Here, as a result of the comparison in step 1103, the following processing is performed on the lines having different data transmission / reception states between the CPU 110 and the line control module 160.

First, it is checked whether or not the transmission packet numbers are different (1109). If the transmission packet numbers are different, it is recognized that some of the data requested to be transmitted by the CPU 110 has not been transmitted to the line control module 160. The same value as that of the data communication table 121 managed in the main memory 120 is set in the data communication management table 231 of the communication interface unit 230 that has newly become the active system (1110). And
Data corresponding to different transmission packet numbers between the CPU 110 and the line control module 160 are registered as first retransmission data to be retransmitted to the communication interface unit 230 which is newly used (1111). If the transmission packet numbers are equal, do nothing. Next, it is checked whether or not the transmission confirmation packet number is different (1112). It is registered in the transmission confirmation packet number 233 of the table 231 (1113). Then, a setting is made so as to notify the CPU of the transmission confirmation for the different transmission confirmation packet numbers. If the transmission confirmation packet numbers are equal, nothing is performed. The transmission packet number 232 newly registered in the data communication management table 231 of the communication interface unit 230 is compared with the transmission confirmation packet number 233 (1114). If the two packet numbers are different, the next packet number is next to the transmission confirmation packet number. Then, the packets from the packet with the number to the last number of the packet number registered as the first transmission data are registered as the second retransmission data for which the data transmission has been completed but the transmission confirmation has not been received (1115). Then, the second retransmission data is first secured and transferred in the communication buffer 237 of the communication interface unit 230, and is placed in a transmission confirmation waiting state. After that, the first retransmission data is transferred to the communication buffer, and the transmission of the first retransmission data to the line control module 160 is awaited. If the transmission number is equal to the transmission confirmation number, nothing is done. Next, it is checked whether or not the received packet numbers are different (1116). If they are different, the received packet number 124 of the data communication management table 121 on the main memory 120 is registered in the received packet number 234 of the communication interface unit 230 ( 11
17). Then, it instructs the line control module 160 to issue a request to retransmit the data for the different packet numbers to the line control module 160 (1118). If the received packet numbers are equal, nothing is performed. Finally, it is checked whether the reception confirmation packet number is different (1119). If not, the reception confirmation packet number 125 of the data communication management table 121 in the main memory 120 is set to the reception confirmation packet number 235 of the communication interface unit 230. Register (1120). And
A setting is made to retransmit data reception confirmation notices for different packet numbers to the line control module 160 (112).
1). If the acknowledgment packet numbers are equal, do nothing. When the above process is completed for all the target lines, a switching completion notification is sent to the CPU. CPU
Then, it recognizes that the switching of the abnormal part has been completed by receiving the switching completion notification, and transmits a communication restart notification to the communication interface unit 230. Thereafter, the data transmission inhibition state for the communication interface unit 230 is released, and the state returns to the normal communication state. In the communication interface unit 230,
When a communication restart notification is received from the CPU, a notification of communication restart is sent to all the line control modules 160 to be switched, and thereafter, a normal communication state is set. Further, when the communication restart notification is received by the line control module 160, the line control module 160 releases the transmission suppression state for the communication interface unit 230, and enters the normal communication state.

As described above, according to the present embodiment, the confirmation of data transmission / reception between the host and the terminal at the line data link level is applied between the line control module 160 and the CPU 110. Data integrity during normal data communication can be guaranteed without using a special protocol. Also, when a failure occurs in the duplexed part on the host side, particularly in the communication interface unit and the computer interface module, and the communication interface unit switches from the active system to the standby system, the switching causes the lost data communication to be lost. The control information can be reproduced from the control information of the data communication held by the CPU and the line control module adjacent to the communication interface unit, and the state before the switching can be reproduced. Can be guaranteed.

FIG. 12 shows an example of another embodiment of the present invention. Hereinafter, a processing procedure when one-to-one communication and multicast communication are mixed will be described with reference to the drawings.

In order to cope with the multicast, in addition to the data communication management information shown in FIG. 1, a data communication management table for the multicaster controlled by the CPU 110, the communication interface unit 130 and the line control module 160 is provided. Further, a communication buffer for a multicaster is provided in the main memory 120 and the communication interface unit 130. Further, a multicast number counter 1228 managed by the CPU 110 on the main memory 120 is transmitted to the line control module 160 by a packet for identifying whether the data packet being transmitted to the line is for one-to-one communication or multicast communication. An identification table 1268 is provided. Also in the multicast communication, the data integrity is assured by operating the communication management table and the communication buffer at the time of data transmission and at the time of transmission confirmation in the same manner as the data communication by the one-to-one communication in the normal data communication. The main memory 120 has a multicast communication table 1221 and the multicast number counter 1228. The multicast communication table 1221 includes a transmission confirmation waiting multicast number 1222,
It has a data issuer 1223 and a final multicast number 1224 as components, which correspond to the active communication interface unit 130. The communication interface unit 130 is provided with a multicast communication table 1231 and a multicast communication buffer 1237. Has as a component. In the line control module 160, the multicast table 1261
And has the packet identification table 1268 for multicast. The multicast table 1261 has a transmission packet number 1262 and a transmission confirmation packet number 1263 as components. Here, in order to identify the data of the one-to-one communication and the multicast communication in the line control module 160, when transmitting a packet from the communication interface unit 130 to the line control module 160, whether the packet is for one-to-one communication or for multicast communication. Is added as additional information.
Then, when the packet is transmitted by the line control module 160, the packet identification table 1268 packet number is registered. When transmitting a transmission completion confirmation from the line control module 160 to the communication interface unit 130, the packet numbers are extracted in the order registered in the packet identification table 1268, and the packet number is used as additional information for transmission confirmation as the communication interface. By transmitting to the communication unit 130, it is determined whether the transmission confirmation is notified by one-to-one communication or multicast.
So that it can be identified. When the communication interface unit 130 receives transmission confirmations for all packets from all transmission destinations corresponding to one multicast, the communication interface unit 130 notifies the CPU 110 that the multicast has ended, Release the corresponding buffer 1237. When receiving a transmission confirmation from all the communication interface units that transmitted the multicast data, the CPU 110 receives a multicast buffer.
Release the corresponding part of 1227.

In the configuration shown in FIG. 12, the processing when the communication interface unit 130 or the computer interface module 150 is abnormal and the active system is switched is performed for reproducing the data management table for one-to-one communication. By performing the same process as that for reproducing the multicast table, it is possible to reproduce the information lost by switching of the communication interface unit 130.

As described above, according to the present embodiment, even in a communication system in which multicast communication and one-to-one communication coexist, data transmission is sequentially controlled, whereby even when an error occurs in a duplicated portion, communication control for communication is performed. Since data can be reproduced, data integrity can be ensured even during normal operation and when switching of a duplicated portion occurs.

[0066]

According to the present invention, since it is not necessary to control the host computer and the terminal using the layer 3 information in order to guarantee the data integrity at the time of normal data communication, the data communication overhead is reduced. Minimize data integrity. In addition, the host computer and a part of the multi-line control device have a redundant configuration, and even when an abnormality occurs in the redundant configuration portion, communication can be continued by switching the active system, and further, by switching the active system. Since the lost data is reproduced, the failure of the Wheat computer prevents the loss of data being communicated with the user or the inability of the user to use the communication system for a certain period of time. Further, according to the present invention, data integrity can be guaranteed even in a communication system in which one-to-one communication and multicast communication coexist, so that a wider communication function is provided to a communication system installer without lowering communication reliability. can do.

[Brief description of the drawings]

FIG. 1 is an internal configuration diagram of a host side of a communication system.

FIG. 2 is a schematic diagram illustrating a configuration of a communication system according to an embodiment of the present invention;

FIG. 3 is an internal configuration diagram of a program operating on a microprocessor of a communication interface unit.

FIG. 4 is an internal configuration diagram of a program operating on a microprocessor of the line control module.

FIG. 5 is a flowchart of data transmission processing of a communication interface unit.

FIG. 6 is a flowchart of data transmission processing of the line control module.

FIG. 7 is a flowchart of data reception processing of the line control module.

FIG. 8 is a flowchart of a data reception process of the communication interface unit.

FIG. 9 is a diagram illustrating processing when the CPU and the line control module detect that an abnormality has occurred in the communication interface unit or the computer face module;

FIG. 10 is a diagram showing processing after switching a communication interface unit to a new active system;

FIG. 11 is a diagram showing processing after switching of the active system of the communication interface unit;

FIG. 12 is an internal configuration diagram of a host according to another embodiment of the present invention.

[Explanation of symbols]

100. Host computer, 110. CPU 120. Main memory, 121. Data communication management table, 127. Buffer, 130. Communication interface unit; 131. 140. data communication management table Multi-line control device, 150. Computer interface module, 160. Line control module, 161. 230. data communication management table Communication interface unit (standby system), 250. 310. Computer interface module (standby system) Data communication processing, 330. Active system switching processing, 350. Diagnostic monitoring processing, 410. Data communication processing, 1221. Multicast communication table, 1228. Multicast number counter, 1227. Buffer for multicast, 1231. Multicast communication table, 1237. Buffer for multicast, 1261. Multicast table, 1268. Packet identification table.

Claims (6)

[Claims] In a data integrity assurance system of a communication system in which data is transmitted between a CPU and a line via at least three or more data transmission buffers when data is transmitted, the data communication path is located closest to the line on the data communication path. The existing elements of the data transmission buffer other than the existing data transmission buffer have a redundant configuration of duplex or more, and the duplex element has a working system and a standby system, and usually only the working system is operating, When a failure occurs in the active system and the communication is continued by switching to the standby system, information for controlling the data communication buffer in the switched element is stored in the data transmission buffer in the switched element. Means for reproducing two data transmission buffers adjacent to each other on the data communication path from information for controlling the data transmission buffers. Omission of data transmission by switching to the system, data integrity guarantee system which is characterized in that to continue without communication to occur duplicate. 2. A multi-line control device that converges and controls a plurality of communication lines, and a host computer connected to the multi-line control device transmits and receives data between an information terminal connected to the plurality of lines. In the data integrity assurance method of the communication system to be performed, the host computer includes:
As internal components, at least a CPU, a communication interface unit for interfacing with the multi-line control device, and a main storage unit are provided in duplicate, and usually only one system is operated as an active system, A system other than the active system is suspended, while a fault-tolerant computer that switches to the standby system and continues operation when the active system fails, and furthermore, the multi-line control device controls one or more lines simultaneously. A line control module and a computer interface module for connecting the multi-line control device to the computer communication interface unit are included in the components, and the computer interface module is connected to the one multi-line control device. The same number of the communication interface units are provided, and the line control module and the computer are provided. In a configuration in which the interface modules are connected on the same bus, a means is provided on the bus so that only one of the computer interface modules can be connected at the same time. A data integrity assurance method, wherein, when switching from a standby system to a standby system, the computer interface module is switched from one connected to the active system to one connected to the standby system. 3. A data integrity assurance system according to claim 2, wherein said communication interface unit and said line control module are controlled by a microprocessor. 4. The data integrity assurance system according to claim 3, wherein each of said CPU, said communication interface unit and said line control module controls (1) order control of transmission and reception data in a unit of data transmission path. (2) means for detecting how many packets of the minimum unit (packet) of the data stored in the communication buffer are data, and (3) how many packets of data have been transmitted or received. Means for storing the data by a packet number continuously attached to the transmission or reception packet; and (4) data received from the upstream side of the data transmission path is retained in the communication buffer even after the data is transmitted to the downstream side. And (5) receiving a transmission completion notification of the data transmitted from the downstream side of the data transmission path to the downstream side. (6) means for reporting a transmission completion notification to the upstream side having received the communication buffer, and (6) means for releasing the data held in the communication buffer by receiving the transmission completion notification from the downstream side. And (7) means for, when the line control module detects that a failure has occurred in the communication interface unit, suppressing transmission to the communication interface unit until a communication enable notification is received from the communication interface unit. )
Means for accepting only a specific command from the communication interface unit in accordance with an instruction from the communication interface unit, further comprising: (9) when switching from the active system to the standby system, Means for notifying the line control module that communication is being prepared; and (10) communication of the individual line control modules with respect to the individual line control modules when switching from the active system to the standby system. Means for requesting transmission of information on the data packet held in the buffer; and (11) when the communication control unit switches from the active system to the standby system and becomes communicable, And (12) when the CPU is switched from the active system to the standby system, Means for receiving information about the data packet held in the communication buffer of the CPU, when switching to the standby system from (13) working system, the C
Means for newly reproducing information on the data packet for the communication interface unit from the PU and information on the data packet collected from the line control module; and (14) information on the data packet for the communication interface unit is reproduced. As a result, the packet number for which the transmission completion notification has been received by the line control module,
If the packet number of the transmission completion notification received by U is different, it is assumed that the transmission completion notification has been received by the communication interface unit up to the packet number of the transmission completion notification received by the line control module. Means for reporting the transmission completion notice to the CPU by the number of packet numbers for which the transmission completion notice has been received between the CPU and the line control module, and (15) when switching from the active system to the standby system, From the information obtained by the means for reproducing the information on the data packet for the communication interface, the data held in the communication buffer of the communication interface unit is retransmitted to the CPU by designating the packet number. Requesting means;
And (16) means for transmitting, to the communication interface unit, information on data packets held in a communication buffer of the CPU when the communication interface unit is switched from an active system to a standby system. And (17) means for retransmitting data of a packet number requested to be retransmitted from the communication interface unit to the communication interface unit, wherein the communication interface unit switches from the active system to the standby system. At the time of the switching, the information for the communication buffer control of the working system of the communication interface unit lost by the switching is reproduced, and at the time of the switching, the data between the CPU and the terminal connected through the communication line is also reproduced. Data integrity assurance method characterized by guaranteeing continuity. 5. The data integrity guarantee system according to claim 3, further comprising: (1) means for dividing the data transmitted from the CPU into packet units to be transmitted to the line to the communication interface unit; Means for allocating a sequence number to the packet, and (3) the CPU
Means for storing the data name of the data transmitted from the server and the final sequence number assigned to the packet obtained by dividing the data in association with each other, and (4) transmitting from the CPU a transmission completion notification received from the line control module in packet units. By providing means for summarizing the data into data units, and by performing data transmission between the CPU and the communication interface unit and a data transmission completion notification in units of a plurality of packets,
A data integrity assurance method characterized by reducing overhead for communication buffer control. 6. The data integrity assurance system according to claim 3, wherein said CPU comprises a multicast transmission means for transmitting the same data to a plurality of lines, and (1) multicast transmission to said CPU and a communication interface unit. Means for distinguishing between trust data and data for one-to-one transmission between the CPU and the terminal, independently assigning and managing a sequence number, and (2) storing a multicast transmission destination, Means for holding the data for multicasting on a communication buffer until a data transmission completion notification is received from the destination, and (3) the data packet received from the communication interface is transmitted by multicasting. Or means for identifying and storing whether the transmission is based on one-to-one transmission, A data integrity assurance method that allows both transmission and one-to-one transmission.