JPS5915587B2 - data transmission system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention makes it possible to automatically perform failure point detection and recovery processing in a data transmission system in which a plurality of data transmission stations are connected in a ring through transmission lines. The present invention relates to a data transmission system.

Conventionally, in this type of data transmission system, as shown in FIG. 1, each data transmission station ST, ST2, .
n units were connected in order to form a ring, but information was transmitted through a single transmission path L to each transmission station ST, , ST
2. If a failure occurs in one data transmission station STi, it will disrupt the information transmission and affect the entire system. It was difficult to detect a faulty station.

Therefore, when a fault occurs, it is necessary to check the operation of each station, detect the faulty station, and remove it from the system. All the separation work was done manually, which was extremely difficult and required a long recovery time, and it had the disadvantage of lacking reliability. The present invention has been made in view of the above circumstances, and includes connecting a plurality of data transmission stations to each other in a ring through two transmission paths, a main transmission path and a backup transmission path. It is configured so that the combination of the transmitting and receiving circuits to be used and the transmitting and receiving circuits to be used can be selected, and each station is cleared for each receiving output, and when the receiving output is interrupted, it is counted up, and the set value is different for each station. When the reception timer counts up, stations equipped with a system recovery function will start failure detection and recovery processing, and stations without a system recovery function will have a main transmission line and backup By replacing the transmitter/receiver circuit connected to the transmission line and making it possible to receive input from the backup transmission line, it is possible to perform a recovery operation on a station that has a system recovery function, detect the failure point, isolate the failure point, and restore the system. It is an object of the present invention to provide a data transmission system that allows reduction reconfiguration to be performed automatically and quickly.

An embodiment of the present invention will be described below with reference to FIGS. 2 to 4.

FIG. 2 shows an example of the overall system configuration according to the present invention.

In the figure, 11 is an active module connected to the data transmission system, such as an electronic computer, process input/output equipment, or peripheral equipment, and 12, 122, 123, . . .
12n is a station connected to this. Each of these stations 12, 122, . The data transmission directions of these two data transmission lines Ll and L2 are opposite to each other, and the data transmission line L2 is normally used as a backup transmission line so that it functions as an information transmission line only in the event of a failure. There is. FIG. 3 shows the configuration of each of the stations 12, 122, . A data transmitting/receiving unit 102 is this data transmitting/receiving unit 1
01 is a reception timer for monitoring the reception input state that is cleared by the reception output of the reception control unit and starts counting when the reception output is interrupted; 103 is a microprocessor; 104 is a read/write memory (RAM); and 105 is a read-on memory. (ROM), and the data received from the data transmitter/receiver 101 or the data transmitted to the data transmitter/receiver 101 is sent to the microprocessor 1 via the common data bus DB.
03, read/write memory 104, and read-on memory 105 based on logic judgment control. In addition, an input/output controller 106 that controls interfaces with external devices connected to the stations 12, 12n is connected to the common bus DB, and transmits data and receives data from other stations via the input/output controller 106. is exchanged between the station and external equipment. FIG. 4 is a diagram showing the configuration of the data transmitting/receiving section 101 having the configuration shown in FIG.
, 202, transmission circuits 203, 204, and reception control section 20
5. It is composed of a transmission control section 206, and is shown in FIG. 4A.
, b, c, d, receiving circuits 201, 202
, the transmission circuits 203 and 204, the reception control section 205, and the transmission control section 206.
Any type of connection can be made.

The received data is sent to the receiving circuits 201, 202 and the receiving control unit 20.
5 to the inside of the station or the transmission control unit 2
06, transmission or reception data is repeated (regenerated relay) from inside the station to other stations through the transmission circuits 203 and 204. Next, the operation of this apparatus having the above configuration will be explained. As shown in FIG. 2, when data is normally exchanged between the stations 121, . . . 12n, for example, the stations 12, .
We will explain what happens when the Under normal conditions,
Each data transmitting/receiving section 101 of each station 12, . . . 12n is in a normal state as shown in FIG. 4a.

That is, one of the data transmission lines Ll, I, and 2 is used as the main, and the other is used as a backup.If L1 is used as the main, in the normal state, the input side of the receiving circuit 202 is connected to the data transmission line L1, and the receiving circuit 202 The output side of is the reception control section 2.
05, and the output side of the transmission control section 206 is the transmission circuit 20.
3, and the output side of the transmitting circuit 203 is the data transmission line L.
1, and a receiving circuit 201 and a transmitting circuit 204 are also connected to a backup data transmission path L2.
The configuration is such that only 202 and 203 out of 3,204 are used for exchanging data. Each station 121・
. . 12n monitors the reception output using the reception timer 102, and if the station 125 fails, the data on the data transmission path L1 for information transmission will be interrupted here.

Each station 12, . . . , 12n has a different time-up time for each reception timer 102, and a program for controlling system failure detection and recovery is stored in the microprogram of the station whose time-up time is the earliest. ing. It is assumed that there are at least two stations in the system that perform failure detection and recovery control, including a backup station. In addition, if the station does not have a function to perform failure detection and recovery control (hereinafter referred to as an SVC station) when the reception timer 102 times up, the data transmission/reception unit 101
, L2, the receiving circuits 201, 202 and the transmitting circuits 203, 204 consider the data transmission path L2 as the main transmission path.
And the reception control unit 205 and transmission control unit 206 are connected to the fourth
The configuration is automatically switched to the reverse state as shown in FIG. b. That is, the receiving circuit 201. The transmission circuit 203 is directly connected and inserted into the data transmission path L1, and the reception control unit 20
5. The receiving circuit 201, which is separated from the transmission control unit 206 and receives data from the data transmission path L2, is connected to the reception control unit 205, and the transmission circuit 204, which sends data to the data transmission path L2, is connected to the transmission control unit 206. connected, receiving circuits 201, 202, transmitting circuits 203, 204
Of these, 201 and 20 are systems related to data transmission path L2.
4 is used for data exchange. In FIG. 2, if station 125 is out of order, for example, if station 12 is an SVC station, this station 12 will be the first to receive reception timer 1.
02 time has expired and failure detection and recovery processing begins.

Station 12 first transmits control information to stations 122, 123, . . . which are stations on the downstream side.

This first control information is sent to the receiving station by the control unit 20 of the data transmitting/receiving unit 101 of that station.
5 is in the left-turning state shown in FIG.
The output of
This is information that instructs the L2 to be switched to a configuration in which the L2 is sent via the L2 and the other components are disconnected. This control circuit transmission may be performed by specifying a destination for each station individually, but in order to shorten processing time, use broadcast communication, rather than specifying individual stations as destination addresses.
You may send by specifying an address that all stations can receive. The SVC station is in the right-turning state as shown in FIG.
The output of the transmission control unit 206 is sent to the transmission circuit 203 which is a transmission circuit to the data transmission path L1, and the configuration is switched to disconnecting the others, and then the second control information is sequentially transmitted to each downstream station one by one. Check the response from the station.

This second control information is appropriate information for checking the functional status of each station. The station receiving this second control information stops the left or right folding state of the transmitting circuit and receiving circuit and sends a response to the SVC station.

Therefore, the SVC station can distinguish and judge between an abnormal station and a healthy station in the downstream station from this response result. A command is given to one of the detected abnormal stations, the earthflow station, to switch the data transmitting/receiving unit 101 to the above-mentioned left-turning state. Next, the SVC station is an upstream station, that is, stations 12n and 12n in FIG.
Detect abnormalities in stations corresponding to -,,.... In the upstream detection process, first, the data transmitter/receiver 101 of the SVC station is switched to the normal state,
Prepare to receive data from the upstream station. S.V.
In a station that does not have a C station function, the data transmitter/receiver 101
The transmitting circuit and receiving circuit are automatically switched to the reverse state shown in FIG. 4b. After confirming the elapse of the time-up time of the reception timer 102 of the downstream station that does not have the SVC station function where the failure point detection and reconfiguration has been performed, the third control information is broadcasted to the upstream station. This third control information is switching control information to the right-turning state, and the station that receives this switches the data transmitting/receiving section 101 to the right-turning state as shown in FIG. 4d. Next, the SVC station sequentially transmits the second control information to upstream stations one by one and checks responses from each station. Therefore, in the SVC station, it is possible to detect a failure point in the upstream station as well as detect and reconfigure the failure point on the downstream side.

That is, it stores the station with no response or abnormal response as a result of the response check, and instructs the previous station to switch the data transmitting/receiving section 101 to the right-turning state. As a result of the above operation, the stations 124 and 126, which are one place before the faulty station 125 in the above example, have data transmission lines Ll and L2, respectively.
The faulty station 125 is separated by using the left-folding state and the right-folding state.

Further, in the SVC station 12, an abnormality in the station 125 is detected by the above-described operation, and by storing it, the failure point can be outputted to the outside and confirmed. In the above explanation, the occurrence of an abnormality in the station 125 has been explained, but similarly, abnormality detection and recovery of the data transmission system due to cable breakage can be realized in a similar manner.

In particular, in the case of a cable break between stations with SVC station functions, in this example, stations 121 and 1
In the case of a cable break between stations 12 and 22, first
However, due to a cable break, the data transmitter/receiver 101 is turned back to the left as shown in FIG. Wait for an hour. On the other hand, the station 122 performs downstream recovery processing, but since the station 12 is in the left-turning state, the reconfiguration of the system including the station 124 is completed.

Next, by processing the upstream side, it is detected that a cable disconnection between the station 12 and the station 122 has occurred. In this case, the backup SVC station 122 will perform the actual system reconfiguration operation. As a result of the above operations, the disconnection of a faulty station can be performed dynamically, quickly and reliably, and therefore the efficient operation of the transmission system can be significantly improved.

In this way, in a data transmission system in which a plurality of data transmission stations that transmit and receive data are sequentially connected to each other in a circular manner by transmission lines, the transmission lines are at least two systems, a main and a standby system, and the transmission directions are reversed. At the same time, each station is provided with separate circuits for transmitting and receiving data corresponding to the transmission path, and the transmitting circuit and the receiving circuit are connected to those corresponding to the backup transmission path. For control that has the function of switching the receiving circuit to one corresponding to the protection side transmission line, the function of switching the receiving circuit to one corresponding to the protection side transmission line, and the function of returning it to the one corresponding to the main side transmission line. Each station is provided with a reception timer with a different time-up time that is cleared every time there is a reception in the device and the receiving circuit and activated when no reception is received, and the station having a reception timer with a faster time-up time is provided. A function is added to the control device to command failure detection and recovery processing at the time of time-up, and during the failure detection and recovery processing, reception is performed on the main transmission path, transmission is performed on the protection transmission path, and transmission is performed on the main transmission path. The side transmission line and reception are sequentially switched and controlled to the protection side transmission line, and other stations that do not have the failure detection and recovery processing function can switch transmission and reception to the protection side transmission line when the reception timer of that station times up. The station in which the time has expired among the data transmission stations having a failure detection and recovery processing function operates the control device of the station and sends a signal for failure detection to each station in turn and receives a response therefrom. If a response is received, the transmission and reception are controlled to be returned to the main transmission line, so when a failure occurs, one transmission line is sequentially transmitted using the main and backup transmission lines. By detecting faults one by one and returning stations without faults to the main transmission path, the faulty stations can be automatically disconnected, and this can be done quickly and reliably, which is very effective in terms of efficient operation of the transmission system. It is possible to provide a data transmission system with excellent features such as not only significant improvements can be made but also failure stations can be easily confirmed.

[Brief explanation of the drawing]

Figure 1 is a diagram for explaining the configuration of a conventional data transmission system, Figure 2 is a diagram for explaining the configuration of a data transmission system according to the present invention, and Figure 3 is a block diagram showing the configuration of a data transmission station. , FIGS. 4A, 4B, 4C, and 4D are diagrams respectively showing various forms of data transmission path selection combinations of the data transmitting/receiving section. 12,,122,...12n...Data transmission station, 101...Data transmitting/receiving unit, 1
02... Reception timer, 103... Microprocessor, 104... Read/write memory, 105... Read only memory, 106...
...Input/output controller, 201, 202...
...Reception circuit, 203, 204...Transmission circuit, 205...Reception control section, 206...
Transmission control unit, Ll, L2...data transmission path.

Claims (1)

[Claims] 1. In a data transmission system, a plurality of data transmission stations that send and receive data are sequentially connected to each other in a ring with transmission paths, and data is transmitted via each adjacent data transmission station. The transmission direction is reversed, and each data transmission station is provided with a separate circuit for transmitting and receiving data, corresponding to each transmission path, and the transmission direction is reversed. A function for selectively switching the transmitting circuit and receiving circuit to those compatible with the backup side transmission line, the transmitting circuit to one compatible with the backup side transmission line, and the receiving circuit to one compatible with the backup side transmission line, and the main side circuit. A control device having a function to restore the transmission path to one compatible with the transmission path, and a reception timer that sets a different time-up time for each data transmission station, which is cleared each time the receiving circuit receives reception and operates when no reception is received. Further, at least one data transmission station among the plurality of data transmission stations having a reception timer with an early time-up time is provided with a function for instructing failure detection and recovery processing when the time-up time is up for the control. , and during failure detection and recovery processing, depending on the location of the other data transmission station, reception will be on the main transmission path, transmission will be on the backup transmission path, or transmission will be on the main side. transmission lines and reception is controlled by switching to one of the transmission lines on the standby side, and other data transmission stations that do not have the above-mentioned failure detection and recovery processing function switch transmission and reception to the standby side transmission line when the reception timer of the station times out. The device for controlling the station is activated so that the station is switched to the transmission path, and when the data transmission station having the failure detection and recovery function times up, the station issues a command for the failure detection and recovery processing to each of the stations. 1. A data transmission system characterized by transmitting data to a data transmission station, checking the response, and returning the transmission and reception to the main transmission line if there is a response.