JPS63234751A - Configuration control method for loop data transmission system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a configuration control method for a loop data transmission system, and particularly relates to a system using optical transmission, in which a loop data transmission system is provided with a bypass switch at each station. The present invention relates to a configuration control method suitable for a transmission system.

[Conventional technology]

In recent years, local area networks have been widely used as intra-company communication systems, etc., and bus-type networks are used for small-scale networks such as those within one floor, and multiple networks of these bus-type networks are used. A loop type network is used for large-scale connections.

The present invention relates to this latter network.

The loop type network is shown in Figure 2.

A supervisory control device 1 (hereinafter referred to as a control station) and transmission control devices 201 to 207 (hereinafter referred to as stations) are connected by loop-shaped transmission lines 3 and 4 in opposite directions, and are connected to computers, various terminal devices, or the like. A bus connecting a plurality of buses is connected to a loop circuit at a station.

In this loop type data transmission system, transmission lines 3 and 4 are provided in opposite directions to improve reliability, but even with this, if one station goes down, neither transmission line can form a loop.

The system goes down. To prevent this, for example, when stations 204 and 205 are down, a so-called loopback configuration is adopted in which the transmission path is looped back at stations 3 and 6 as shown in FIG. A configuration control method for establishing this loopback configuration is described on pages 192-196 of ``100 Mbit/sec Ring-Type Optical Local Network Connecting Bus-Type Networks'' (Nikkei Electronics, 1983, No. 12.5). The high-speed type and reliable type are known.

In high-speed loopback, a first signal is first broadcast from the control station to all stations. When each station receives this first signal, it returns a response to the upstream station in the flow of this signal via a transmission path in the opposite direction. Subsequently, a second signal is broadcast from the control station to all stations. When each station receives the second signal, the stations that have received a response from the downstream side do not change their loop configuration, and the stations that have not received a response return the signal from the upstream side to the upstream side. Switches the input/output of the own station and enters a loopback state. The above operations are performed for each transmission path. This method is effective in the event of obvious failures, such as station power outages, and can reconfigure the line in 200 to 300 milliseconds.

The other reliable type requires 1 to 2 seconds for reconfiguration, but it tests each station one by one to ensure loopback, and is usually the high-speed type mentioned above. is executed first, and then executed when the problem cannot be removed.

In this method, for example, in the case of FIG. 2, the control station 1 connects the station 2 to
01 (the control station stores the address of each station, and communicates with station 1 using this address designation). station 2
If the control station 01 is normal, the control station 18 returns a response with its own station in a loopback state when it receives this first signal. When the control station 1 receives this response, it sends a command to station 1 to cancel the loopback, and when the loopback is canceled, it performs the same operation on the next station 202.

If this is repeated, no response will be returned from the faulty station or the transmission line section, so at this time, control station 1 will be one step higher than the station currently under test.
A command is sent to the previous station (on the upstream side) to perform a loopback, thereby placing the station in a loopback state. If the above operation is also performed in the opposite direction, a loopback as shown in FIG. 3, for example, is completed.

[Problem that the invention seeks to solve]

When the line is reconfigured by loopback, depending on the abnormal location within the loop, a plurality of loops may exist in the form of islands, and the system may become unusable. For this reason, a system has been developed in which a bypass device is provided at the connection point between each station and the transmission line, and when the power is cut off, the station is bypassed using this switch so that downstream stations can be connected. However, when this system performs the conventional loopback configuration control described above, if there is no response to a command, it is immediately determined that there is an abnormality, and the upstream station loops back, causing the downstream stations to be disconnected. , it may no longer function as a bypass.

An object of the present invention is to provide a system that uses both a loopback configuration and a bypass as described above, so that even if there is a bypassed station on the way, subsequent normal stations can be connected to the loop during loop banking. The present invention provides a configuration control method for a data transmission system.

[Means for solving problems]

The purpose of the above is to, in the above-mentioned reliable loopback configuration control, when there is no response to the first signal from a certain station, loopback is not immediately performed at the previous station, but a predetermined number of stations are consecutively looped back. This is accomplished by looping back to the last station that responded when there is no response.

[Effect]

Loopback is not performed unless there are a specified number or more consecutive bypass stations, so
Most of the stations on the loop have been disconnected;
The disadvantage of the ineffectiveness of providing a bypass device is eliminated.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail. FIG. 4 is a block diagram showing the structure of a control station or station, in which a transmission line bypass device 10A is provided on transmission lines 3 and 4 (optical transmission lines).

10B is connected to the signal modulation/demodulation section 11A via this device.
, IIB are connected to each transmission path correspondingly. These signal modulation/demodulation sections are connected to a data input bus 13° and a data output bus 1.
4. It is connected to the control section 12 via a control bus 15 . Normally, data is transmitted using the transmission line 3, and a monitoring signal is sent to the transmission line 4 to check the state of the transmission line. In addition, transmission line bypass device 10A
.

In 10B, when the power of the station is on, the contact side is on and the transmission lines 3 and 4 and the signal modulation/demodulation section 1 are connected.
1A and IIB are connected.

When the power of the station is turned off or due to manual operation, the a side contact is turned on, and the signal modulation/demodulation section 11A,
IIB is disconnected and the station is bypassed to save the system from going down.

FIG. 5 is a block diagram showing details of the signal modulation/demodulation section of FIG. 4. The optical signal that has passed through the transmission line bypass section 10A or 10B is sent to the photoelectric converter 20 via the cable 40. Here, the optical signal is converted into an electrical signal, and a clock is extracted by a clock tuning circuit 21 and sent to a decoder circuit 22, respectively. The data and clock demodulated and converted from serial to parallel signals are sent to the control circuit 2.
3 to the input bus 13. Also.

As will be described later, special patterns used for controlling the transmission line, such as loopback commands, are stored in the C8T command receiving buffer 24 and are placed on the control bus 15 via the C5T command reading register 25. There is also a status register 26 for storing various states of the device, which is also read via the control bus 15. Transmission data from the control unit 12 is sent to the selector 33 . via the output bus 14 . The data is converted from parallel to serial data and from electrical to optical signals via the encoder 32 and the electro-optical converter 31 and sent to the cable 41. In addition, when this device is used as a control station, command data is written from the control bus 15 to the C3T command writing register 36, sent through the multiplexer 35 to the C8T command pattern storage register 34, and the selector 33 is It is sent out to the transmission path via the

In addition, commands such as the above operations are sent to the control write register 2.
9. The command register 28 is written from the control bus 15 to determine the operation of the device.

Further, the selector 30 for selecting a register is a register that stores instructions for selecting each of the above-mentioned registers.

Furthermore, there is a selector 27 for selecting a clock, and the mode is changed depending on how the device is used.

By the way, the flow of data within the station when a loopback configuration is adopted is as follows in FIG.

That is, input data from the transmission line 3 is transmitted to the transmission line bypass section 10A, the cable 40. The signal is sent to the control section 12 via the input bus 13 via the signal modulation/demodulation section 11A. The data passing through the control section 12 is transferred to the output bus 14. Transmission line 4 via signal modulation/demodulation unit 11B, cable 41, and transmission line bypass unit 10B
sent to. In order to have the above configuration,
Commands from the control station are required, but
This command is realized in a format as shown in FIG. The command is 8 bytes long, the first 2 bytes are a synchronization pattern, the 3rd byte is a code indicating the type of command, the 4th byte is inverted data for double inversion transmission, and the 5th and 6th bytes are The station address indicating the destination to which the command is issued and its inverted data, and the 7th and 8th bytes are data indicating whether transmission line 3 is used or transmission line 4 is used, and its inverted data. Here, examples of a designated loopback transition command and a designated loopback release command are shown. As explained earlier in FIG. 5, in a general station, these command data are input to the C3T command receiving buffer 24 and the C3T command reading register 25, and read into the control unit 12 via the control bus 15. .

The control unit 12 interprets the command data, and based on its effect, issues a loopback configuration command to the two signal modulation/demodulation units 11A and 11B via the control bus 15.

In a loop type transmission line having a control station and a station having the structure and functions as described above, 1
In the present method, the control station executes the process shown in FIG. 1, and each station executes the process shown in FIG. 7.

First, in the process shown in Figure 1, the control station
First, a designated loopback transition command is issued to the first station seen from the own station (step 10).
o). Next, it is checked whether or not there is a response to this command (step 101), and if there is a response, a loopback cancellation command for the first station is issued and the process moves to the second station (step 105). Below is the second similar process.

Repeat step 3, and if there is no response, go to step 1.
028, where a specified loopback command is issued to the next station. If there is a response at this time (step 103), a loop variation release command is issued to the station in question and the process proceeds to the next station (step 106).
, 100), if there is no response, the process moves to step 104, where it returns to the previous station two stations, issues a specified loopback command to this station, and ends the process.

On the other hand, as shown in FIG. 7, when each station receives a designated loopback command from the control station (step 701), it performs address check 7 (step 702), and if the address of its own station is designated, it loops back. takes the back configuration and returns a response to that effect to the control station (step 703)
. Although not shown, the same applies when a loopback release command is received.

Execution examples of the processes shown in Figs. 1 and 7 above are shown in Figs. 8 to 1.
This will be explained with reference to Figure 9. In these figures, it is assumed that the stations 202, 204, 205, and 207 are in a bypass state by being powered off or manually operated. In this case, the stations 204 and 205 are in the bypass state for two consecutive stations, but in the optical transmission line, the loss of light quantity is particularly large in the optical bypass device, and if the stations are bypassed consecutively, the light level decreases, causing unstable movement as a loop. There are things to do. That is, this is because the optical receiver functions in an analog manner. When such a situation occurs, it is difficult for the system to determine which station is abnormal, and the system must automatically and reliably check each station one by one. The method used for this is the reliable type, that is, the designated loopback method.

When this process is started, the control station 1 first issues a specified loopback transition command to the station 201 in FIG. In response to this, the station 201 enters the loopback mode and returns a response by looping back the transmission line 3 to the transmission line 4. When the control station 1 receives the response, the control station 1 releases the loopback state by issuing a designated loopback release command, and then issues a designated loopback transition command to the station 202 as shown in FIG. Since this station 202 is in a bypass state, it cannot receive five commands.

Therefore, no response is returned to control station 1 either. In the conventional method, the process returns to the station 201 and enters the loopback state, but in this embodiment, the process advances to step 102 in FIG. 1 and issues a loopback transition command to the next station 203. The situation at this time is shown in FIG. Then, the command is received, a loopback state is established, and a response is returned, so the process returns to step 100. It then proceeds to station 204 as shown in FIG. No commands are received here and no response is returned.

Then, as shown in FIG. 12, the process further proceeds to station 205. Here too, the command is not received and no response is returned, so
Control station 1 moves to step 104 in FIG. 1 due to the non-response at these two consecutive stations, and issues a designated loopback transfer command back to station 203 as shown in FIG.

This completes the processing in the counterclockwise direction, and now the same processing in the clockwise direction is performed at stations 207, 206, . . . in this order. The situation at this time is shown in FIGS. 14 to 19, and the loop configuration shown in FIG. 19 is finally completed.

As described above, two consecutive bus-passed stations 204 and 205 are likely to cause unstable operation.
is separated from the loop, and the stations that were bypassed alone remain connected within the loop (in the bypass state).

In addition, in this embodiment, if there are two consecutive bypassed stations, that part is cut out, but depending on the characteristics of the system, it may be cut out if there are three or more stations in a row. Good too.

〔Effect of the invention〕

According to the present invention, when disconnecting a failed station using the specified loopback method, stations that are not continuously in a bypass state at least a predetermined number are not disconnected from the loop, so that the disconnection of bypassed stations can be minimized. This has the effect of allowing the system to be operated without unnecessarily separating normal stations from the loop.

[Brief explanation of drawings]

Figure 1 is a diagram showing the flow of designated loopback control at the control station, Figure 2 is a configuration diagram of a general loop transmission system, Figure 3 is a diagram showing the loopback configuration state, and Figure 4 is a diagram showing the flow of designated loopback control at the control station. Fig. S is a block diagram showing the details of the signal modulation/demodulation section.
7 is a diagram showing an example of a command format, FIG. 7 is a diagram showing a flow of control in a station, and FIGS. 8 to 19 are diagrams illustrating loopback control according to the method of the present invention. 1... Control station, 3, 4... Transmission line, 10A, IOB... Transmission line bypass section, 11A. 11B... Signal modulation/demodulation section, 12... Control section, 201
~207...Station.

Claims (1)

[Claims] 1. In a loop data transmission system in which a control station and a plurality of stations are connected in a loop by two transmission lines whose transmission directions are opposite to each other, a control station is connected to a station along the transmission direction of each transmission line. The control station is provided with a function of transmitting the first command in order from the one closest to the control station, and when the control station receives the first command while operating normally, the control station sends a response indicating that the first command has been received normally. Each station is provided with a function to return the command to the control station via a transmission path in the opposite direction to the transmission path through which it was sent, and the control station transmits a predetermined number of responses to the first command sent sequentially. If, and only then, the station that sent a response last sends a second command to control the transmission path from the control station back to the transmission path in the direction of the control station. A configuration control method for a loop data transmission system, characterized in that: