JPH04274630A - Data automatic re-start system - Google Patents

Abstract

PURPOSE:To reduce a transfer time by adding a serial number to a transfer data at a sender side and transmitting data again whose serial number is missing automatically when missing of data takes place. CONSTITUTION:A sender side is provided with a serial number addition means 2 reading one by one transmission data from an input data file 5 and adding a serial number after a data part, a transmission management file 7 managing a serial number, a transfer data file 6 storing the transfer data having a serial number for a predetermined period, a data transfer means 3 reading and sending the transfer data in the order of serial numbers, and a receiver side is provided with a reception management file 10 storing and managing the serial number of the transfer data whose reception is finished normally to a reception side and a data reception means 9 calculating the serial number of the transfer data to be sent again when the serial numbers of the received transfer data are discontinuous, informing the result to the sender side and requesting the re-transmission, and when missing of data takes lace, the missing data is automatically sent again.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic data retransmission system, and more particularly to an automatic data retransmission system for data transfer performed by configuring a transmission path between terminals or between a terminal and a host through line connection processing.

0002

[Prior Art] As shown in FIG. 7, as a method for managing transmitted and received data in data transfer between terminals and between a terminal and a host using a conventional line connection method, a start request message and a start approval message are sent following line connection processing. After exchanging and transferring multiple pieces of data from the sending side, the number of data items that have been transferred this time is communicated to the receiving side in the final message sent when all data transfer is completed, and the number of data items transferred on the receiving side in the final message. Generally, the success or failure of transmission and reception is determined by comparing the number of data items actually received.

[0003] As a result of verification, if a discrepancy in the number of data items is detected due to some reason, the receiving side informs the sending side of the reception abnormality by sending a reception end message (NG) and urges the sending side to resend the data. Since it is not possible to detect whether a reception error has occurred in the item, the sending side generally retransmits all data.

0004

[Problems to be Solved by the Invention] In the conventional automatic data retransmission system described above, if data is lost during the transfer due to some kind of failure on the line, the abnormality in the transfer can be detected by checking the number of data sent and received. , since it is unclear which data item has been omitted, all data is retransmitted, which has the disadvantage of lengthening the transfer time.

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic data retransmission system that eliminates the above-mentioned drawbacks, retransmits only necessary data, and shortens transfer time.

[0006]

[Means for Solving the Problems] The automatic data retransmission system of the present invention configures a transmission line between two stations through line connection processing and transfers data, and when the receiving side cannot normally receive the transferred data, In the data automatic retransmission method that causes the sender to resend data, the sender has a transmission management file for storing and managing the sequential numbers added to the transferred data that has been sent, and an input for temporarily storing the transmitted data. Serial number adding means for sequentially reading transmission data to a specified destination from a data file, editing it into transfer data in a transferable format, and adding a consecutive number to each item by referring to the management file; A transfer data file that retains transferred data for a predetermined period of time, and a transfer data file that reads and transmits the transfer data in the order of consecutive numbers added from this transfer data file. The receiving side has a reception management file for storing and managing sequential numbers of transferred data that has been successfully received, and a data transfer means for retransmitting data, and a reception management file for storing and managing the sequential numbers of transferred data that have been successfully received, and data receiving means that determines that reception has been completed normally when the serial number is consecutive, and when it is discontinuous, refers to the reception management file and notifies the transmitting side of the serial number of the transfer data to be retransmitted and requests retransmission; It is configured with.

[0007]

Embodiments Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the functional configuration of an embodiment of the present invention.

In the automatic data retransmission system of this embodiment, as shown in FIG.
Then, the transmission data destined for the other station to be transmitted is read one by one from the input data file 5, and as shown in FIG. 2(b), the transmission management file 7 is referred to after the data part that has been converted into a transferable format. a serial number adding means 2 for adding sequential numbers (hereinafter referred to as serial numbers) in the order of transfer, a transfer data file 6 for storing transfer data to which serial numbers have been added until the end of the next data transfer, and a transfer data file. It is provided with a data transfer means 3 that reads and transmits transfer data in the order of serial numbers starting from 6, and a communication management section 4 that performs line connection and disconnection processing and manages communication. The transmission management file 7 is shown in Figure 6 (
As shown in a), the number of transferred data that has been sent and the value obtained by adding 1 to the serial number added to the last transferred data are stored for each destination as the next transfer serial number, and the number of transferred data is It manages whether the transfer has been completed or not, and when transferring to the same destination next time, the serial number adding means 2 refers to the transmission management file 7 and adds a serial number starting from this next transfer serial number. Note that when the data transfer means 3 receives a retransmission request from the receiving side, it immediately stops transferring the data, reads the transfer data from the transfer data file 6 according to the designated serial number, and resumes the transmission.

The receiving side includes a communication management unit 8 that performs line connection and disconnection processing and manages communication, and a reception management file 10 that stores and manages serial numbers of transferred data that have been successfully received.
and a data receiving means 9 that performs a process of receiving transfer data.
Reception data file 1 that stores normally received data
It is composed of 1. The data receiving means 9 determines that reception has been completed normally when the serial number of the received transfer data is consecutive to the serial number of the previously received transfer data, and stores the received data in the reception data file 11. At the same time, the reception management file 10 is updated. As shown in FIG. 6(b), in the reception management file 10, the number of successfully received transfer data and the serial number of the last received transfer data are stored as reception completion serial numbers for each partner transmitting station. It is stored and manages the success or failure of data transfer on the receiving side. If the serial numbers of the received transfer data are discontinuous, refer to the reception management file 10, add 1 to the reception completion serial number to calculate the serial number of the transfer data to be retransmitted, notify the sending side, and resend. request. The data receiving means 9 compares the reception completion serial number of the reception management file 10 with the serial number of the data transferred from the sending side, and determines that the serial number of the transferred data is the value obtained by adding 1 to the reception completion serial number. If there is, it is determined to be normal, and the necessary reception processing is performed on the transferred data and written to the received data file 11.

[0011] That is, the transmitting side adds a serial number to the transferred data and transmits it, the receiving side checks the serial number of the transferred data, and if the data is discontinuous, the receiving side informs the transmitting side of the missing data. It notifies you of the serial number of the transferred data that has occurred (or the first data if data is missing all at once), reads the transferred data file based on the notified serial number on the sending side, and automatically resends it. .

Next, the actual data transfer procedure will be explained.

FIG. 3 is an explanatory diagram of the processing procedure during normal data transfer in this embodiment, with line connection and disconnection processing and data transfer processing in the center, and accompanying internal processing on the sending and receiving sides, respectively. Shown on the left and right.

First, after performing line connection processing in the same way as in the conventional data transfer example shown in FIG. 7, the sending side reads the next transfer serial number regarding the connected receiving side from the management file 7.
The message type of the control message format shown in Figure 2(a) is
A start request message with the read next transfer serial number added to the serial number field is transferred to the receiving side.

[0015] The receiving side reads the reception completion serial number regarding the connected sending side from the management file 10 in response to the start request message transferred from the sending side, and adds 1 to this to calculate the serial number to be received this time. do. Next, check the serial number in the transferred start request message and the calculated serial number to be received this time, and if they are the same, set the message type of the control message format to "start message" and enter the status in the status field. A start approval message (OK) with "OK" set is transferred to the sending side. Note that if the numerical values do not match, the serial number error process shown in FIG. 5, which will be described later, is performed.

[0016] Upon receiving the start approval message (OK) transferred from the receiving side, the transmitting side moves on to transferring actual data, assigning a serial number to each data item and transmitting the data. On the receiving side, the serial numbers of the received data are checked one by one, and the data whose serial numbers are confirmed are written to the received data file 11. At the same time, the reception completion serial number in the management file 10 is updated with the serial number of the data written in the reception data file 11.

[0017] When the transmitting side completes the transfer of all data, it sets the message type of the control message format as "end message" and transfers the final message with the next transfer serial number set in the serial number field to the receiving side. The receiving side receives this final message, checks it with the serial number to be received next time, and if it is the same value, sets the message type of the control message format to "end message" and sets the status field to "OK". (OK) is transferred to the sending side. When the transmitting side receives this reception end telegram (OK), the transmitting side performs line disconnection processing and completes the entire transfer.

FIG. 4 is an explanatory diagram of the processing procedure when data dropout occurs during data transfer. Similar to the normal state in FIG. 3, upon receiving a start approval message (OK) in response to a start request message, the sending side starts transferring actual data. If a data omission occurs due to some reason and data (2) is missing, and the receiving side receives data (3) when it should have received data (2), a serial number error is detected. Here, set the message type of the control message format as "end message", set "NG" in the status field, and set the serial number of the data that caused the data dropout (2 in this example) in the serial number field. Telegram (
NG) is forwarded to the sending side and prompted to resend.

The sending side reads the corresponding data from the transfer data file 6 based on the serial number of the received reception end message (NG), and receives a retransmission start request message (message type is retransmission message) with the serial number set. Transfer to the side. The receiving side checks the serial number of the retransmission request and the serial number of the retransmission start request message, and if they match, the transmitting side sends a retransmission start approval message (message type is retransmission message) with "OK" set in the status field. Transfer to. The sending side receives the retransmission start approval message and starts retransmitting the actual data. The status section of the retransmission start approval message is “
In the case of "NG", the transfer data file 6 is reread and the retransmission procedure is repeated.

FIG. 5 is an explanatory diagram of the process when a discrepancy occurs between the serial number set in the start request message at the start of data transfer and the serial number to be received this time calculated from the management file 10 on the receiving side. . If the next transfer serial number (for example, 5) set in the start request message does not match the serial number that should be received this time managed by the receiving side, the receiving side will write "" in the status and serial number sections of the control message format, respectively. A start approval message (NG) in which "NG" and "sequential number to be received this time" (for example, 3) are set is transferred to the sending side. The sending side reads the corresponding data from the transfer data file 6 based on the serial number of the start approval message (NG), and starts data transfer using the same procedure as in the case of retransmission in FIG. 4. As a result, even if a failure occurs during data transfer during the previous connection and does not recover, and the line connection process is performed again without exchanging the final message and reception end message, which is the normal reception completion process, , data loss can be prevented and data can be transferred efficiently.

[0021] In the above embodiment, the transmission management file records the next transfer serial number obtained by adding 1 to the serial number of the completed transmission, and the reception management file records the reception completion serial number of the successful reception. Although it has been described that the receiving side adds 1 to the reception completion serial number and notifies the sending side when requesting retransmission, various methods of recording and converting in each management file can be considered. In addition, although it has been explained that the serial numbers are managed for each partner station and the data transferred during past connections are totaled, the serial numbers are not managed by totaling them for each partner station.
As management for each line connection process, the serial number may be updated to an initial value at the time of line disconnection process.

[0022]

[Effects of the Invention] As explained above, the automatic data retransmission system of the present invention adds serial numbers to transferred data, manages the serial numbers on both the sending side and the receiving side, and prevents data loss from occurring. Since retransmission is automatically performed starting from the transferred data where data loss has occurred, there is an effect that the transfer time required for retransmission can be shortened.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the functional configuration of an embodiment of the present invention.

FIG. 2 is a format diagram of a control message and transfer data in this embodiment.

FIG. 3 is an explanatory diagram of a processing procedure during normal operation in this embodiment.

FIG. 4 is an explanatory diagram of a processing procedure when data dropout occurs in this embodiment.

FIG. 5 is an explanatory diagram of another example of operation when data dropout occurs in this embodiment.

FIG. 6 is a record format diagram of a management file in this embodiment.

FIG. 7 is an explanatory diagram showing an example of a processing procedure of a conventional data transfer system.

[Explanation of symbols]

1 Data input means 2. Sequential number addition means 3 Data transfer means 4,8　　　　Communication Management Department 5 Input data file 6 Transfer data file 7 Transmission management file 9 Data receiving means 10 Reception management file 11 Received data file

Claims (2)

[Claims] [Claim 1] Automatic data retransmission that configures a transmission line between two stations through line connection processing and transfers data, and causes the transmitting side to retransmit the data when the receiving side cannot properly receive the transferred data. In this method, on the sending side, data to be sent to a specified destination is sequentially read from a transmission management file for storing and managing sequential numbers added to transmitted data and an input data file for temporarily storing transmitted data. serial number adding means for editing the transfer data in a transferable format and adding a consecutive number to each item by referring to the management file; and transfer data for retaining the sequentially numbered transfer data for a predetermined period of time. The receiving side includes a file and a data transfer means that reads and transmits the transfer data in the order of serial numbers added from the transfer data file and retransmits the transfer data from the designated serial number when a retransmission request is received. A reception management file for storing and managing the sequential numbers of transferred data that has been successfully received, and a file that indicates that the received transferred data has been successfully received when the sequential number of the transferred data is consecutive to the sequential number of the previously received transferred data. an automatic data retransmission system, comprising: a data receiving means that refers to the reception management file and notifies the transmitting side of the serial number of the transfer data to be retransmitted and requests retransmission when it is determined that the data is discontinuous. 2. The transmission management file and the reception management file store and manage independent serial numbers for each partner station to be communicated with, and the transfer data file stores and manages data for the next line connection process to the same partner station. 2. The automatic data retransmission system according to claim 1, wherein the transferred data is held until the end of the transfer.