JPH10135967A - Error-reporting method and data communication system for realizing the error reporting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the time required for re-transmission and to improve the operation efficiency of a terminal by preparing a re-transmission request in the common control part of the node and returning it to an origination terminal, when an error has been generated in the node. SOLUTION: The error judgment part 13b of the node 10b stores the data M in a transmission/reception buffer part 15b, when no error is present in them. If an error is detected, its is reported to the common control part 14b. The common control part 14b returns re-transmission request data for which information for indicating the re-transmission request is written through an input/output part 11b and a transmission line 21 to the terminal 1. The input/output part 12a of the node 10a which receives the request data addressed to the terminal 1 from the node 10b performs transmission through the input/output part 11a and the transmission line 20 to the terminal 1 when no error is present in the request data in the error judgment part 13a. The terminal 1 receives them, resets a standby timer to the data M activated at present and re-sends the data M.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to communication processing in a node constituting a data communication system.
The present invention relates to an error notification method when an error occurs in data and a data communication system for implementing the method.

[0002]

FIG. 3 shows an example of a data format applied to a conventional data communication system, where M is data, H is a header, SA is a destination address, DA is a source address, and I is a source address. Is an information section, C is a check section, and E is an end section.

FIG. 4 shows a configuration example of a conventional data communication system, wherein 1 and 2 are terminals, 10a to 10c are nodes, 11a to 11c and 12a to 12c are input / output units,
Reference numerals 13a to 13c denote error determination units, and reference numerals 20 to 23 denote transmission paths connecting the terminal 1 to the node 10a, the node 10b to the node 10c, and the node 10c to the terminal 2, respectively.

[0004] Here, the operation of the error notification method in the conventional data communication system will be described with an example of data transfer from terminal 1 (which becomes a calling terminal) to terminal 2 (which becomes a receiving terminal). The same applies to data transfer.
In the following description of the data transfer, it is assumed that the transmitting terminal has issued a data transfer request instruction to the receiving terminal in advance. This data transfer request instruction is performed in the same procedure as in the prior art, and therefore the description is omitted.

First, the transmitting terminal 1 writes the address of the receiving terminal 2 in the destination address portion SA in the data frame, the address of the own terminal 1 in the source address portion DA, and the header portion H indicating the beginning of the data M. And an operation for detecting an error in the data, for example, a CRC (Cyclic Redunda
An error check operation such as ncy Check) is performed, and the result is put on a check unit C to generate data M. The generated data M is transmitted to the node 10a via the transmission line 20.

The node 10a receiving the data M inputs the data M into the input / output unit 11a. Input / output unit 11a
Transfers the data M to the error determination unit 13a. Data M
The error judging unit 13a that has received the command again performs the same operation (CRC check operation or the like) as the error check operation performed by the terminal 1, and compares the operation result with the information of the check unit C in the data M. If the result matches, the data M
Is determined to be normal, and is transmitted from the input / output unit 12a to the next node 10b via the transmission path 21.

The input / output unit 11b in the node 10b that has received the data M transfers the received data M to the error determination unit 13b. The error judging unit 13b includes the error judging unit 1
An error check operation similar to 3a is performed. Where data M
If no error is detected, the node 10b performs the same processing as that of the node 10a described above, and transmits the data M to the next node 10c via the transmission line 22. However, in this example, it is assumed that an error has been detected in the data M at the node 10b.

An error judging section 13 which has detected an error in the data M
In b, data Mx is generated by performing processing such as (a) adding information indicating that an error has occurred to the end unit E, and this data is transmitted from the input / output unit 12b to the next unit via the transmission line 22. Or (b) discards the data M received from the node 10a.

Case (a). In the node 10c that has received the data Mx, an error check similar to that performed by the preceding nodes 10a and 10b is performed. The error determination unit 13c detects an error in the data Mx. However, since information indicating that an error has occurred is already added to the end E of the data Mx, the data Mx is transmitted from the input / output unit 12c as it is. The data is transferred to the receiving terminal 2 via the road 23. The receiving terminal 2 that has received the data Mx knows from the fact that an error has occurred added to the end portion E in the data Mx that the data M cannot be normally received, and responds to the data M that has been activated up to that time. The reception waiting timer is reset, and a retransmission request is made to the transmitting terminal 1.

Case (b). When the data M is discarded at the node 10b, the receiving terminal 2 knows that the data waiting cannot be normally received due to the expiration of the reception waiting timer because no data comes after that. A retransmission request is made to the calling terminal 1 as in the case of (a). The operation described above is repeated until data can be transferred between the nodes without error, and the data transfer is finally completed.

[0011]

In the conventional data communication system, the following problem arises due to the above-described retransmission procedure. That is, in the case of the above (a), even if an error in the data M is detected at the intermediate node, the retransmission request is always made only from the receiving terminal 2. Even if an error is detected, the receiving terminal 2 must make a retransmission request while waiting for the transmission of the data Mx, and the transmission time between the node that detected the error in the data M and the receiving terminal 2 At least twice the time (time for round trip) is wasted.

In the case (b), the data M is discarded at the node where the error is detected and the data is not transferred to the subsequent nodes, so that the traffic efficiency is improved. And for the receiving terminal 2,
An error cannot be detected until the reception timer monitoring time is exceeded, resulting in an increase in the standby time of the receiving terminal 2 and a reduction in the processing efficiency of the entire system. The present invention has been made to solve the above problems, and to provide an error notification method that shortens the time required for retransmission processing and effectively uses the processing time in a terminal, and provides a highly efficient data communication system that realizes the method. The purpose is.

[0013]

In order to achieve the above object, an error notification method according to the present invention is an error notification method in a data communication system for transferring data via one or more nodes (nodes 10a ...). An error determining step of determining whether there is an error in data received from the originating terminal (1) or the node (node 10a...) In the preceding stage, and a case in which it is determined in the error determining step that there is no error in the data Storing the data in a storage means (transmit / receive buffer unit 15a,...); And retransmitting the data to the calling terminal (1) when the error determining step determines that the data has an error. A retransmission notification step of notifying the request and notifying that the retransmission request has been made to the receiving terminal (2).

The transmitting terminal (1), when notified of the retransmission request in the retransmission notifying step, retransmits the data, resets a reception acknowledgment signal waiting timer corresponding to the data, (2) is characterized in that upon receiving a notification that a retransmission request has been made, a data reception waiting timer corresponding to the data is reset.

Further, the data communication system of the present invention comprises:
In the data communication system for transferring data via the above nodes, each node determines whether or not there is an error in the data received from the originating terminal (1) or the node (10a...). (Error judging unit 13a
), Means for storing the data when the error determination means (error determination section 13a) determines that there is no error (transmission / reception buffer section 15a), and error determination means (error When the determination unit 13a determines that the data has an error, the retransmission request is sent to the calling terminal (1), and the retransmission request is sent to the receiving terminal. A retransmission notification unit that performs

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, it is determined whether or not there is an error in data received from an originating terminal or a node at the preceding stage. If it is determined that there is no error in the data, the data is stored. When it is determined that there is an error in the data, it notifies the transmitting terminal of a request for retransmission of the data and notifies the receiving terminal that the retransmission request has been made.

Thus, when the node detects a data error, the node replaces the receiving terminal, makes a retransmission request to the transmitting terminal, and further informs the receiving terminal of the above-mentioned retransmission request. Notice. As a result, it is possible to reduce the end-to-end transmission time required for retransmission when an error occurs in the data, and to further reduce the time required for the retransmission processing by the transmitting terminal and the receiving terminal to other processing. This makes it possible to implement a highly efficient error notification method and a data communication system with improved data processing and communication efficiency on a network.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an example of a data format applied to the data communication system of the present invention, where M is data, H is a header, Hi is a data identifier provided in the header H, and SA is a destination address. , DA is a source address section, I is an information section, C is a check section, and E is an end section.
The data format of the present embodiment is different from the conventional data format shown in FIG. 3 in that a data identifier is provided in the header portion H.

FIG. 2 shows a configuration example of the first embodiment of the data communication system of the present invention. In the figure, 1 and 2 are terminals, 10a to 10c are nodes, 11a to 11c and 12a to 12c are input / output units, 13a to 13c are error determination units, 14a to 14c are common control units, and 15a to 15c are transmission / reception buffers. Units 20 to 23 are transmission paths. The data communication system of this embodiment is different from the conventional data communication system shown in FIG. 2 in that a common control unit and a transmission / reception buffer unit are provided.

In this embodiment, when no error is detected in the data (including general data) received by each node, the data is temporarily stored in the transmission / reception buffer unit of the node, and the data is sequentially stored in the next buffer. To the node (or terminal 2). In this embodiment,
It is assumed that no error is detected in the data M by the error determination unit 13a of the node 10a and an error is detected by the error determination unit 13b of the node 10b. In this case, the operation until an error is detected by the error determination unit 13b of the node 10b has been described in the description of the conventional technique except that the normal data M is stored in the transmission / reception buffer unit 15a of the node 10a. Since the same operation is performed, the description is omitted. Hereinafter, the node 10b
The description will be started from the point in time when the error judgment unit 13b detects an error in the data M sent from the node 10a.

When the error determination unit 13b detects that an error has occurred in the data M, the common control unit 14
Notify b. In order to request retransmission of the data M, the common control unit 14b having received the notification from the error determination unit 13b first refers to the contents of the source address SA and the destination address DA of the data M, and transmits the data M. It is confirmed that the terminal is the terminal 1 and the receiving terminal is the terminal 2.

Next, the common control unit 14b adds information indicating the retransmission request of the data M to the data identifier Hi, and generates data M1 in which the information indicating the retransmission request is also written in the information unit I, and outputs the data M1. The data is transmitted from the unit 11b to the terminal 1 via the transmission path 21. Also, the common control unit 14b
Generates, at the same time as the operation described above, data M2 in which retransmission instruction completion information indicating that a retransmission request has been made to the terminal 1 for data M is added to the data identifier Hi, and the input / output unit 1
2b to the terminal 2 via the transmission path 22.

The input / output unit 12a in the node 10a receiving the data M1 addressed to the terminal 1 from the node 10b transfers the data M1 to the error judgment unit 13a. The error determination unit 13a that has received the data M1 performs an error check on the data M1, and if there is no error, notifies the common control unit 14a of the fact and temporarily stores the data M1 in the transmission / reception buffer unit 15a. The common control unit 14a having received the notification that the data M1 has no error transmits the data M1 from the input / output unit 11a to the terminal 1 via the transmission path 20.

When an error is detected in the data M1 received from the node 10b by the error determination unit 13a of the node 10a, the error is notified to the common control unit 14a. Upon receiving this notification, the common control unit 14a adds the information indicating the retransmission request of the data M1 to the data identifier Hi, generates the data M11 in which the information indicating the retransmission request is also written in the information unit I, and outputs the data M11. The transmission is performed from 12a to the node 10b via the transmission path 21. The node 10b that has received the data M11 generates the data M1 again using the data M stored in the transmission / reception buffer unit 15b, and performs the same processing as that described above. At the same time as the above-described operation, the common control unit 14a generates data M12 in which retransmission instruction completion information indicating that a retransmission request has been issued to the node 10b for the data M1 is added to the data identifier Hi, and the input / output unit 1
1a to the terminal 1 via the transmission path 20.

Next, consider the data M2 generated by the node 10b that has detected the error. The same operation as that of the node 10b described above is performed on the data M2 sent from the node 10b to the node 10c via the transmission path 22. That is, when no error is detected in the data M2, the data M2 is determined to be normal and the transmission / reception buffer unit 1
5c, and is transmitted from the input / output unit 12c to the terminal 2 via the transmission path 23.

When the error of the data M2 is detected by the error judgment unit 13c of the node 10c, information indicating a request for retransmission of the data M2 is added to the data identifier Hi.
Data M in which information indicating a retransmission request is also written in information section I
21 is generated and transmitted from the input / output unit 11c to the node 10b via the transmission line 22. Data M2 from node 10c
The node 10b that has received 1 performs the same processing as the operation of the node 10a when receiving the data M1 from the node 10b. At the same time as the above-described operation, the common control unit 14c generates and inputs data M22 in which retransmission instruction completion information indicating that a retransmission request has been made for the data M2 to the terminal 1 is added to the data identifier Hi. The data is transmitted from the output unit 12c to the terminal 2 via the transmission path 23.

The terminal 1 that has received the data M1 from the node 10a resets the ACK wait timer corresponding to the currently activated data M, transmits the data M again, and waits for the ACK corresponding to the retransmitted data M. Start a new timer. Further, the terminal 2 that has received the data M2 from the node 10c can reset the timer that has been started to receive the data M so far, and if there is another process, can start that process. The operation in each node and terminal described above is repeated until the data M can be transferred via each node without error.

As described above, in this embodiment, when it is confirmed that there is no error in the data, the data is stored in that node, and when an error is detected in a certain node, the data is stored in the node. The retransmission request data in which the information indicating the retransmission request is written in the identifier Hi and the information indicating the retransmission request is written in the information section I is returned to the transmitting terminal 1, and the transmitting terminal 1 retransmits normal data M. This allows
Data collision can be avoided, and the time required for retransmission processing is at least twice as long as the transmission time required between the node 10b and the terminal 2 where an error was detected (time required for round trip) as compared with the conventional technique. Can be shortened, so that
For the terminal 1, the time for holding the communication data M for retransmission can be reduced, and a part of the time can be allocated to the memory for other disk processing. In addition, the time that the terminal 2 waits for receiving the communication data M can be shortened, and a part of the time can be used for the memory for other disk processing or the like as in the terminal 1. . According to this configuration, as a result, the speed of data transfer is increased, and an efficient error notification method and a data communication system can be provided.

[0029]

As described above, according to the present invention, 1) the time required for retransmission when a data error occurs can be reduced, and 2) the retransmission at the transmitting terminal and the receiving terminal can be performed. By transferring the time required for other processing to other processing, efficient operation can be performed at the terminal.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a data format according to the present invention.

FIG. 2 is a diagram showing one embodiment of a data communication system according to the present invention.

FIG. 3 is a diagram showing an example of a conventional data format.

FIG. 4 is a diagram illustrating a configuration example of a conventional data communication system.

[Explanation of symbols]

1, 2: terminal, 10a-10c: node 11a-11c, 12a-12c: input / output unit, 13a-
13c: error determination unit 14a to 14c: common control unit, 15a to 15c: transmission / reception buffer unit 20 to 23: transmission line M: data, H: header unit, Hi: data identifier provided in header unit SA: destination address Part, DA: source address part,
I: Information part C: Check part, E: End part

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[Procedure amendment]

[Submission date] November 1, 1996

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[Procedure amendment 4]

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Claims (5)

[Claims] 1. An error notification method in a data communication system for transferring data via one or more nodes, comprising: an error determining step of determining whether there is an error in data received from a preceding calling terminal or node; A storage step of storing the data in the storage means when it is determined in the error determination step that the data has no error;
A retransmission notifying step of notifying the transmitting terminal of a request for retransmission of the data and notifying the receiving terminal that the retransmission request has been made, when it is determined that the data has an error in the error determining step; An error notification method comprising: 2. The error notification method according to claim 1, wherein the transmitting terminal retransmits data when notified of a data retransmission request by the retransmission notification step. 3. The error notification method according to claim 1, wherein the transmitting terminal resets a reception confirmation signal waiting timer corresponding to the data when receiving the data retransmission request. Error notification method. 4. The error notification method according to claim 1, wherein the receiving terminal waits for data reception corresponding to the data when receiving a notification that the retransmission request has been made. An error notification method, comprising resetting a timer. 5. A data communication system for transferring data via one or more nodes, wherein each of the nodes includes an error determination unit that determines whether there is an error in data received from a preceding transmitting terminal or a node. A means for storing the data when the error determination means determines that there is no error; and a means for storing the data when the error determination means determines that the data has an error. Make a resend request,
A data communication system comprising retransmission notifying means for notifying a receiving terminal that the retransmission request has been made.