JPH02119336A - System for making communication protocol into redundant structure - Google Patents

Abstract

PURPOSE:To keep the coherency of transmission sequence even when an error occurs in a direction opposite to that of the result of an event by attaching a data sequence No. on each of data, checking the system of the data sequence No. in a transmission station and a reception station, checking the validity of the data, and performing the deletion or the execution of a processing. CONSTITUTION:On a transmission station side, a procedure from the transmission of the data to the reception of response data is defined as a transmission procedure of one cycle, and the data sequence No. set first is attached on arbitrary transmission or reception data during that cycle. On the transmission station side and a reception station side, judgement for the validity of the data and a following data processing are performed on such data format by the following logic. Namely, the reception station side, in the case of receiving the data, and when the data sequence No. attached on the data being increased by one for the data received in a preceding transmission procedure of one cycle, performs the following processing assuming the reception data as valid data. The data in a case other than that is deleted.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) This invention realizes the integrity of the transmission sequence even when the course of error occurrence occurs in the opposite direction to the flow of events. This invention relates to a communication protocol redundancy system that uses 1q.

(Prior Art) FIG. 11 is a block diagram showing the basic functional configuration regarding transmission to which this method is applied.

In addition, in the figure, 7a is the user prompt (1 to n), 7
b is a transmission task, 70 is a reception task, 7d is a transmission initialization task, 7e is a transmission driver, 7 is a reception driver, 7
g is a transmission control unit, 7h is a transmission buffer, 71 is a reception buffer, 7j is a [1-Cull buffer, 7 is data storage information, 71 is a transmission path, 7m is a transmission control CPLJ, and 7n is a main CP LJ.

This type of transmission control function is performed by the main CP l-J7.
The data and control processing flow is roughly divided into a portion executed by the transmission control CPU 7ta and a portion executed by the transmission control CPU 7ta.

? However, in FIG. 11, user task 1 (7a
) makes a transmission request, the data and control are first notified to the transmission task 7b.

The transmission task 7b adds appropriate header information to the transmission data, stores the data in the transmission buffer 17h, and then activates the transmission driver 7e.

The transmission driver 7e transfers the data in the transmission buffer 77h to the local buffer 7j in the transmission control CPU (7m), and activates the transmission control unit 7g.

After controlling the dex length of the data in the local buffer 7j, adding CRC redundancy information, etc., the transmission control unit 7q
The D/Δ-converted data is sent to the transmission path 7.

When the local buffer 7j becomes empty, the transmission control unit 7Q notifies the transmission driver 7C of a transmission completion interrupt signal, and at that timing the transmission driver 70 reads the status information 7k and sends the result to the user task 1 via the transmission task 7b. (Notify 7a>.

On the other hand, in the case of reception, the transmission control unit 7g receives the received data.
Each time the A/D converted data is checked for CRC redundancy information, it is stored in the local buffer 7j, and an interrupt signal is sent to the reception driver 7f.

If the status information 7k is normal, the receive driver 7 transfers the data from the local buffer 7j to the receive buffer 71, and if a text end code is detected in the received data, starts the receive task 7C.

After checking the data chain structure, the receiving task 7C activates the user task 7a and passes the data to it.

If the status information 7k is abnormal, the following procedure is generally performed.

If a status information abnormality is detected during the transmission process, the transmission initialization task 7d is activated and the transmission side tlflcPL
Initialize J (7m) and transmit/receive driver 7e.
, 'N and tasks 7b and 7c are initialized.

When detected during the reception process, if the status abnormality is fatal, initialization is performed in the same way as for the transmission status abnormality, otherwise the received data is discarded. However, the user task 7a is not notified of the received message.

In order to continue the transmission procedure in response to errors that occur in a series of transmission and reception procedures as described in 1 above, various redundant Q processing is performed at the user task level in the upper layer of the transmission procedure. .

This will be explained with reference to FIG. In addition, J'3 is shown in the figure.
1a is station Si, 1b is station Sj
, 1c is diagnostic timer monitoring, 1d is data transmission, 1C is E
GK response transmission, 1" is NACK response transmission, 1g is setting of the diagnostic timer, 1h is diagnostic timer reset after timeout occurs, and 1j is transmission completion status abnormal retry.

The transmitting station 5i (1a) transmits data (1d)
After sending (3) check the completion status (1J), if the status is abnormal, execute the retransmission procedure.

If the transmission completion status is normal, set signal tie Y (1 (+), ACK (1e) or NAC
K (if) Monitor the time until data is received.

If the diagnostic timer times out in diagnostic timer monitoring (1G), a retransmission procedure is executed (11).

On the other hand, at the destination station 5j (1b),
The received data (1d) is checked for validity and data loss, and if normal, data (1e) is sent to 80, and if abnormal, NACK data (1[) is sent.

FIG. 13 shows a timing chart based on the block 1.1 of the transmission procedure shown in FIG. 12 above.

In addition, in the same figure, 6a is the transmitting station idle state, 6b
is the receiving station idle state, and 6C is the idle state waiting for ΔCK/NΔCK fff1. , 6d is the process of receiving data from the user task, 6e is the process of transmitting data and receiving the transmission status, 6 is the process of receiving CK or NACK, 6g is the process of receiving data, 611 is ΔCK/
Processing to send NACK and receive/receive transmission status, 6
1 is the process of passing the kneezab 0gram received data, 6j is the process of retransmitting data when a transmission status error occurs, 6 is the process of retransmitting when NACK is received, 6 is AC
Monitoring data reception when receiving K/NACK - 6II1 is a timer setting process when transmitting data, 6n is a timer reset process when receiving ΔCK/NACK, and 60 is a process for retransmitting data when the monitoring timer times out.

Flowcharts of this transmission procedure are shown in FIGS. 14 to 17.

In other words, FIG. 14 is a flowchart of the procedure when transmitting data at the source station, FIG. 15 is a flowchart of the procedure when receiving data in the last month of transmission, and FIG. 16 is the procedure when receiving ACK/NACK at the source station. FIG. 17 is a flowchart of processing after the diagnostic timer times out.

(Problems to be Solved by the Invention) The problems to be solved by the present invention will be explained with reference to FIGS. 18 and 19.

FIG. 18 is a correlation diagram of the transmission status at the transmitting station, and FIG. 19 is a correlation diagram of the transmission status at the receiving station.

In Fig. 18, 8a is the main CPU, 8b is the data/address bus, 8c is the transmission control CPU, 8d is the transmission line, 8e is the data transmission request route, 8f is the normal transmission completion status route, and 8g is the abnormal transmission destination. r status through 1~. 8b is a route for normal data transmission, and 81 is a route for data transmission/failure in data transmission.

Further, in FIG. 19, 9a is a normal data input route, 9b is an abnormal data input route, 90 is a normal data reception route, and 9d is an abnormal reception/unfriendly route (8 routes).

In FIG. 18, when a data transmission request (8e) is made by the user task, there are the following four patterns for the transition of the transmission status J'3 to the transmitting station.

■: 8e -)8h -+8j■=8e →8
1 → 8g ★■: 8e → 8h → 8g ■; 86-+8i-+8f Similarly, for the receiving station, in Fig. 19, ■': 9a →9C ★■': 9b →9d ■': 9a →9d ■7: There are four patterns: 9b → 9C.

The problem here is the case of pattern (2) at the transmitting station and pattern (2) at the receiving station.

In all of these patterns, even though the transmitting station determines that data transmission has failed,
This is a case where the receiving station ends up receiving normal data.

In this case, the transmitting station determines that data transmission has failed, and therefore retransmits the data.

On the other hand, on the receiving station side, although normal data has already been received and the processing thereof has been completed, the receiving station side performs the processing upon receiving further normal data.

At the same time, the receiving station side uses AC for the first data reception.
A K/NACK is returned to the source station, but an ACK/NACK response is also returned to the second data reception.

Therefore, although the transmitting station expects to receive only one ACK/NACK6, it receives two ACK/NACKs.
CK will be received, and the subsequent sequence cannot be continued.

After the above process, the transmission sequence ends up hanging.

This invention was made in view of the above problems,
The purpose of this is that even if the course of occurrence of an error occurs in the opposite direction to the flow of events (as described above),
An object of the present invention is to provide a communication protocol redundancy system that realizes uniformity of transmission sequences and improves transmission reliability.

[Structure of the invention] (Means for solving the problem) In order to solve the above problem, this invention
In a distributed processing system in which U exchanges information with each other via a transmission path, the transmitting station adds a unique data sequence ratio for each destination station to the transmitted data as redundancy information, and the receiving station side Then, the validity of the received data is determined by checking the series of sequence errors in the received data, and the transmitting station ends the transmission procedure for the cycle only when it receives response data from the destination station. (Operation) According to this J: configuration, on the receiving station side, the data sequence ratio of the received data is checked, and the data sequence ratio is updated. If the validity of the received data is not recognized, the transmitting station will not receive response data from the destination station.
Even when the aforementioned error occurs in the opposite direction to the flow of events, such an error can be reliably recognized and consistency in the transmission sequence can be achieved.

(Example) First, the principle of the system of the present invention will be explained with reference to FIGS. 1 and 2.

FIG. 1 is a diagram showing a transmission data format according to the present invention, and FIG. 2 is a diagram showing a conventional transmission data format.

In addition, in FIG. 1, 11a is the transmission data text,
11b is transmitting station data transmission, 11c is transmitting station ACK/
NACK response, 11d is the response data text of the receiving station,
11e is the ACK/NACK response of the receiving station, 11" is the response data transmission of the receiving station, and 10a is the second cause.
is the transmission text, 10b is the transmission station transmission data 2.11c
is the transmitting station transmission data, n-1, 10d is the receiving station ACK/
This is a NACK response.

As is clear from a comparison between Fig. 1 and Fig. 2, in the present invention, on the transmitting station side, the period from data transmission to response data reception is defined as one cycle of transmission procedure, and the transmission procedure during this cycle is Any transmitted and received data will be appended with the initially set data sequence.

For such a data format, the transmitting station side and the receiving station side perform data validity ft determination and subsequent data processing using the following logic.

The transmitting station side adds a data sequence ratio when transmitting data. Here, the data sequence ratio is one for each destination station, and is incremented by one each time one cycle of transmission procedure is completed.

After that, when ACK/NACK data or response data is received, if the data sequence ratio added to it matches the data sequence at the time of data transmission), it is processed, otherwise it is /NAC
Discard K data or response data.

On the other hand, on the receiving station side, when data is received, the data sequence ratio added to the data is 11 compared to the data received in the previous one-cycle transmission procedure. The received data is validated and subsequent processing is performed.

In other cases (the data sequence ratio is the same as the previous time or smaller), the data is discarded.

Similarly, 80K as a response to the response data transmission.
/ When receiving ACK data, if the data sequence ratio added to it matches the data sequence ratio at the time of data reception, perform that processing, otherwise discard the △CK/NACK data. do.

A block diagram of a transmission procedure based on the method described in F is shown in FIG.

The present method differs from the conventional method shown in FIG. 12 in the following points.

In FIG. 4, 12 indicates data rejection due to data sequence proton matching, 121 indicates ACK/NACK rejection due to data sequence hawk mismatch, 12n indicates response data transmission, 120 indicates response transmission to 80 for response data, 1
20 is a NACK response transmission for response data, 12p is a diagnostic timer set for response data, 12Q is a diagnostic timer reset for response data, 12r is a retry after a timeout occurs for response data, 123 is response data discarded due to data sequence mismatch, 12[ is an ACK/NACK rejection due to a data sequence proton match.

Conventionally, ACK/NA for data transmission
Although the period up to the reception of CK data was defined as one cycle of transmission procedure, in the present invention, the period up to reception of response data from the transmission optical layer is defined as one cycle of transmission procedure.

Furthermore, in contrast to the prior art, in the present invention, f-
ACK/N△CK rejected M(1
2+) and response data discarded due to failure of data sequence statement f! I (12s) processing procedure is added, and on the receiving station side, data is rejected due to data sequence proton matching (12s).
ACK/NA due to k) and data sequence seniority matching
A processing procedure for CK rejection (12d) is added by ζ1.

As a result of adding 1 to the characteristic (e) above, the method of the present invention can achieve the following effects.

FIG. 3 is a transmission timing chart according to the present invention.

In the figure, 6p is an idle state waiting for response data, 6q is an idle state waiting for a response from the user task,
6r is in ACK/NAC (Yoshira idle state, 6S is a process of receiving and receiving response data, 6t is a process of transmitting 8GK/NΔCK and receiving Send I3 status, 6u is a process of passing response data to the user task, 6v is the process of receiving and receiving response data from the user task, 6W is the process of transmitting the response data and receiving the transmitted data, and 6X is the process of △CK/NA
6y is the process of rejecting the received data, 6z is the process of @fJ1 for the received ACK/NACK, 6aa is the process of rejecting the received response data, 6
ab is a process of rejecting the received ACK/NACK.

In the case of the method of the present invention, unlike the conventional technique shown in FIG. 12, the transmitting station side discards the received ACK/N△CKffff! (6z) and a process (6aa) for rejecting received response data, and a process (6y) for rejecting received data and a process (6ab) for rejecting received ΔACK/NACK on the receiving station side.

That is, in the process (6y) of discarding the received data, the positive data sequence is checked for the received data, and the data is processed only if it is increased by 1 compared to the previously received data. Otherwise, the data is rejected.

In the process (61) of rejecting the received 80/NACK, the data sequence value of the received ACK/NACK is checked, and only if it matches the data sequence output at the time of data transmission, the GK/NACK data is sent to the received ACK/NACK. The transmitting station considers this to be valid and shifts to an idle state with response data.

Otherwise, it's 80/NACK is rejected and it's 80/
The state with a NACK response continues.

In addition, in the process (6aa) of rejecting the received response data, the data sequence of the received response data is checked, and only if it matches the data sequence output at the time of data transmission, the response data is considered valid. In other words, the transmission 11 is 8G K/N for the response data.
Perform ACK transmission processing.

Otherwise, discard the received response data if) t,
Then, it continues the idle state waiting for response data again.

In addition, a process (t
3ab) t- is for the received ACK/NACK,
Examine the data sequence output and only if it matches the data sequence positive at 8 o'clock, then /NACK that 80 o'clock.
The transmitting station considers the data to be valid and shifts to an idle state. Otherwise, the ACK/NACK is rejected and the state is set to idle.

Next, a control program for concretely implementing the system of the present invention based on the above principle will be explained with reference to charts 70-17 of FIGS. 5 to 10.

In the following explanation, only the characteristic parts of the present invention will be explained in detail, but the flowchart 17-1 will be explained in detail.
Since the instructions are written in ordinary sentences, those skilled in the art will be able to easily understand them.

FIG. 5 is a flowchart showing the processing at the transmitting station when transmitting data. In the same figure, in the process of step 29, a data sequence unique to the transmission data at that time is always added to the transmission data.

FIG. 6 is a flowchart showing the processing at the receiving station when receiving data. In the figure, the data sequence 2 is verified through the processes of steps 3k and 31, and if it has increased by +1 from the data sequence interval at the time of previous reception, the received data is validated. Otherwise, the received data is discarded.

FIG. 7 is a flowchart showing the processing when receiving ACK/NACK at the transmitting station. In the same figure, in step 411, 1 is added to the ACK/NACK.
- The sequencer is checked and compared with the sequencer at the time of data transmission, and if there is a mismatch, its ACK/NA
The CK data is rejected (step 41).

FIG. 8 shows I, ? at the receiving station. 5 is a flowchart showing processing when transmitting 5-answer data. In the same figure, in the process of step 50a, the data sequence at the time of normal data reception is extracted, and in the process of step 50b, it is added to the response data, and the result is transmitted (step 50C).

FIG. 9 is a flowchart showing processing when response data is received at the transmitting station. In the figure, step 60b
Through the process of step 60C, the data sequence pigeon is verified, and if it matches the data sequence error at the time of data transmission, the response data is validated. Otherwise, the received response data is rejected (Step 6).
The process now advances to flowchart 1 showing the process when receiving CK. In the figure, in steps 70tl and 700, the data sequence added to the ACK/NACK is checked and compared with the sequence at the time of response data transmission, and if they do not match, the ACK/NACK data is discarded. (Step 70f) According to the above embodiment, even when an error occurs in the direction J'3 opposite to the pattern dyeing result, the -1 property of the transmission sequence can be realized.

This will be explained below by taking as an example the case of pattern (1) shown in item 10 of the problem to be solved by the above-mentioned invention.

The transmitting station determines that the data transmission has failed, so γ−
Retransmits the next one. On the other hand, the receiving station side has already received normal data, but when receiving data for the second time,
Since the data sequence positive is the same as the previously received data, it is rejected.

Therefore, the ACK/NACK response is executed only once. However, it is possible to continue normal transmission procedures despite such a pattern of transmission abnormalities.

Furthermore, as one cycle of the transmission procedure, the transmitting station is structured so that it must always receive response data from the previous month, so if the transmission control CPU 7m shown in FIG. Even if data is lost due to a stop, the transmission procedure can be continued when restarted.

[Advantageous Effects of the Invention 1] As is clear from the above explanation, according to the method of the present invention, a data sequence number is added to each data, and the data sequence number is assigned at the transmitting station and the receiving station. By checking the validity of the data by examining the sequence of data, and discarding the data or executing processing, the integrity of the transmission sequence is achieved even when an error occurs in the opposite direction to the result of the event. be able to.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the transmission data format in the present invention, Fig. 2 is a diagram showing the transmission data format in the prior art, Fig. 3 is a diagram showing a transmission timing chart in the present invention, and Fig. 4 is a diagram showing the transmission data format in the present invention. FIG. 5 is a block diagram showing the transmission procedure according to the invention, FIG. 5 is a flowchart showing the processing at the time of data transmission at the transmitting station, FIG. 6 is a flow chart showing the processing at the time of data reception at the receiving station, and FIG. Flowchart showing the procedure for ACK/N 80 at the transmitting station, FIG. 8 is a flowchart showing the process when transmitting response data at the receiving station, and FIG. 9 is a flowchart showing the process when receiving response data at the transmitting station. - Fig. 10 is a flowchart showing the processing when receiving △CK/NACK at the receiving station, Fig. 11 is a block diagram showing the basic functional configuration related to transmission to which this type of system is applied, Fig. 12 1 is a block diagram showing a transmission procedure based on the conventional technology.
Figure 3 shows the timing chart based on L4 in Figure 12, Figure 14 is a flowchart showing the procedure for transmitting data to the source layer, and Figure 15 shows the procedure for receiving data in the transmitting optical layer. Flowchart showing the procedure, FIG. 16 is a flowchart showing the procedure when receiving ACK/NACK in the source layer, FIG. 17 is a flowchart showing the process after the diagnostic timer times out, and FIG. Correlation Diagram FIG. 19 is a correlation diagram of the transmission stapler at the receiving station. 11a... Transmission data list 111)... Transmitting station data transmission 11c... △CK/NACK response of the transmitting station 11d...
・Receiving station response data Acquist 11 f3...Receiving station's ACK/NACK response 11f...Receiving station's response data transmission

Claims (1)

[Claims] In a distributed processing system in which a plurality of CPUs exchange information with each other via a transmission path, a transmitting station assigns a unique data sequence number for each destination station to transmitted data. is added as redundancy information, and on the receiving station side, the sequence number of the received data is added. The validity of the received data is determined by checking the sequence of data sequence No., and only when response data is received from the destination station, the transmitting station ends the transmission procedure of the cycle and assigns the data sequence No. A communication protocol redundancy method characterized by updating the communication protocol.