JPH02179134A - Highly reliable terminal connection equipment - Google Patents

Abstract

PURPOSE:To limit the influence of a fault recovery to a faulty line only and to attain quick restoration of communication by providing a terminal connection equipment for the active system and the standby system connecting a terminal equipment to the line and switching the operating terminal equipment to the standby system when the fault of the active system is detected by a fault detection circuit. CONSTITUTION:A terminal equipment 95 is connected normally to a transmission line via an active system terminal connection equipment 91. When a fault takes place in the active system terminal connection equipment 91, it is detected by a fault detection circuit 93 and informed to a switching control circuit 94. Then the switching control circuit 94 switches the operating terminal connection equipment from the active system terminal connection equipment 91 into the standby system terminal connection equipment 92. Thus, fault restoration processing is applied quickly while the fault is limited to the faulty line only without giving the influence of the fault restoration on other line to restore the communication between terminal equipments at the fault of the terminal connection equipment such as a line set and highly reliable network is constituted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a terminal connection device that is highly reliable against failures and the like for connecting data terminals to lines in, for example, a time division multiplexed LAN.

The purpose is to quickly restore communications when a terminal connection device fails, while limiting the impact of failure recovery to only the failed line.

Active and standby terminal connection devices for connecting terminals to the line, a fault detection circuit that detects the occurrence of a failure in the active terminal connection device, and a fault in the active terminal connection device that is detected by the fault detection circuit. A switching control circuit for switching the terminal connection device in use from the active terminal connection device to the standby system 81'' unconnected device is provided.

[Industrial application field]

The present invention relates to a terminal connection device such as a line center for connecting a terminal to a line M2 in a time division multiplexed LAN (Local Area Network), and in particular, the present invention relates to a terminal connection device such as a line center for connecting a terminal to a line M2 in a time division multiplexed LAN (Local Area Network), and in particular, in the event of a failure of such a terminal connection device, communication between terminals can be quickly restored. The present invention relates to a highly reliable terminal connection device that can

LANs are installed in factories and offices, and play an important role as part of networks.

In particular, line cents, which are connection units for data terminals,
Since it controls communication between data terminals, its failure causes line disconnection, which becomes a big problem if it is an important possibility. Therefore, when a failure occurs in a line set, it is necessary to quickly restore the line in order to increase the reliability of the system.

[Conventional technology]

Figure 5 shows a ring-type LAN and is part of Figure 1.

81 is a supervisor node (central monitoring node).

82.83 is a multiplexer node (line multiplexing node)
, 7 are data terminals, and multiplexer nodes 82 .
The data terminal 7 is connected to 83 by line safety (821.831).

A basic configuration example of a conventional line set 821, 831 is shown in FIG. In the figure, 21 is the reception gate
22 is a parallel/serial conversion circuit 123 is a driver;
24 is a receiver, 25 is a serial/parallel conversion circuit,
26 is a transmission gate 527 is a time slot (TS) counter, 28 is a time slot (TS) register, and 29 is a comparator.

30 is an AND gate, 31 is a fault detection circuit, and 32 is an alarm register.

Data input from the transmission path is separated in the common section 9 and then sent to the line center. At line set 7, after passing through the reception gate 21, the parallel/serial conversion circuit 2
2, the data is converted into serial data and sent to the data terminal 7 via the driver 23.

The data from the data terminal 7 is transferred to the receiver 24 in the reverse procedure. The signal is sent to the common section 9 through the serial/parallel conversion circuit 25 and the transmission gate 26.

There, the signals are multiplexed and sent out on the transmission path.

The opening and closing of the receiving gate 2+ and the transmitting gate 26 are controlled to access only the time slots assigned to the own line set. Namely.

The value of the time slot address used by each station is set in the TS register 28 by the microprocessor, and the value of the time slot counted by the TS counter 27 is set by the time slot clock CL extracted from the transmission line signal in the common section 9. When the value matches the value of the TS register 28, the output of the comparison 329 becomes "1". At this time, if the 1 communication enable signal CE is "l", the gate 21.26
will open.

Here, the communication enable signal GE is a signal indicating whether or not the corresponding line set is operable, and is sent from the microprocessor in the common section 9 to the line set. This communicable signal C
E is “0” when the line center is in a failure state or when there is a command from the central monitoring node 81.
is set to .

In that case, the gates 21 and 26 are closed and communication is interrupted.

The occurrence of a failure in the line set is detected by the failure detection circuit 31, and when a failure occurs, an alarm flag is set in the alarm register 32 by the failure detection circuit 31.

The microprocessor reads this and communicates the communication ready signal CB.
is changed from "1" to "O".

Conventionally, when a fault occurs in the above-mentioned line cent, a maintenance person isolates the faulty line cent and replaces it with another line cent.

Alternatively, as shown in FIG. 7, if the node accommodating the line center of one important line is duplicated, and line center failure occurs.

There is also a method of switching each node.

In FIG. 7, 81 is a central monitoring node, 8284.8
5. 86 is a line multiplexing node, 87 is a data branching device, 8
8 and 89 are switching devices, and two circuits are connected to each city node 85 and 8.
6 constitutes a duplex node. Case 1 of this system: For example, node 85 is the active node, and if its line set becomes a failure while the active node 85 is in operation, switching devices 87 and 88 are switched to the backup node 86 to continue operation. .

[Problem to be solved by the invention]

Identifying and replacing the faulty line is the simplest method, but it takes time to isolate the faulty line and prepare a spare line set, making it difficult to respond quickly. I can't. In addition, in cases where multiple lines are accommodated on one line set circuit board, if one line fails, other lines accommodated on the same line center may also be affected by line disconnection etc. when replacing the line set board. receive.

Further, in the method of switching each node in the event of a line set failure using the duplex configuration shown in FIG. 7, all lines accommodated in the node will be momentarily disconnected at the time of switching due to a failure in one line.

Furthermore, since a spare notebook and switching device must be prepared, this becomes uneconomical if there are few lines to be duplicated.

Therefore, the present invention provides a highly reliable terminal connection device that is capable of quickly restoring communications when a terminal connection device such as a line center fails, while limiting the effects of failure recovery to only the failed line. The purpose is to

[Means to solve the problem]

FIG. 1 is a diagram illustrating the principle of the present invention.

The highly reliable terminal connection device according to the present invention connects 95 terminals to one line.
A terminal connection device 91 for the active system and the standby system for connecting the terminals.
92, a failure detection circuit 93 that detects the occurrence of a failure in the active terminal connection device 93, and a failure detection circuit 93 that detects the occurrence of a failure in the active terminal connection device 93; and a switching control circuit 94 for switching from the terminal connection device 92 to the standby terminal connection device 92.

[Effect]

Normally, the terminal device 95 is connected to the transmission line via the active terminal connection device 91. When a failure occurs in the active terminal connection device 91, this is detected by the failure detection circuit 93 and notified to the switching control circuit 94. As a result, the switching control circuit 94 switches the terminal connection device to be used from the active terminal connection device 91 to the backup terminal connection device 92.

〔Example〕

An actual example of the present invention will be described below with reference to one drawing.

An example of the configuration of a line multiplexing node using a terminal connection device as an embodiment of the present invention is shown in FIG.

In FIG. 2, 1 is a repeater, 3 is a demultiplexer (data separation unit), 4 is a multiplexer (data multiplex unit), 5 is a microprocessor, 6° to 6n are duplex line sets configured duplex according to the present invention, and 71 7n are data terminals connected to the duplex line centros 1 to 6n, respectively.

Here, the repeater 1 is a circuit that receives a signal received from a transmission path, takes in reception data RD from the signal, inserts transmission data SD into the signal, and relays the signal to send it out to the transmission path.

The demultiplexer 3 extracts received data RD addressed to its own station from the received signal of the repeater 1.

The clock CLK synchronized with the time slot of the received signal is extracted, and these are connected to the duplex line sets 61 to 61, respectively.
Send to 6n. In addition, the multiplexer 4 is connected to the data terminals 71 to
The transmission data SD received from 7n via the duplex line sets 6 to 611 is multiplexed and sent to the repeater l.

Repeater l inserts this multiplexed signal into the time slot position assigned to its own station in the received signal from the transmission path, and sends it out to the transmission path.

The microprocessor 5 performs various controls within the node, and here it sets the values of the TS registers of the duplex line centros 1 to 6n, and controls each duplex line set 61 to 6.
Monitoring the failure status of n, each redundant line centro 1 to 6n
It controls the sending of communication enable signal CB to the terminal.

Basic details of this duplex line set 61 to 6n 1
is shown in FIG. The duplex line set 6 roughly includes an active line set section 61, a standby line center section 62, and a duplex control device 63. The active system line set section 61 and the standby system line center section 62 have almost the same configuration as that explained in FIG.
.

is inputted not directly from the microprocessor 5 but from the 5-duplex control device 63.

The duplication control device 63 includes receivers 41 and 42 that receive data received from line set units 61 and 62, and receiver 4.
Selector 43 for selectively outputting 1 or 42 output signals.
Driver 4 sends the selected output to data terminal 7 kZ
4. Receiver 45 for receiving transmission data from data terminal 7. A driver 46 that sends the transmission data to line set units 61 and 62. It is configured to include a CE control section 47.

The CE control unit 47 receives a communication enable signal CEN from the active line set unit 61 and a communication enable signal C from the backup line set unit 62.
EE is input, and the CB control unit 47 creates a communication enable signal CE based on these.

A communication enable signal CE is sent to the AND gate 3ON of the active line center section 61, and a communication enable signal CE is sent to the AND gate 30E of the standby line center section 62, respectively.

At the same time, the selector signal 5EI- is input to the selector 43 to control switching of the selector 43.

This CE control section 47 can be composed of inverters 471, 473 and an AND circuit 472 as shown in FIG. 4, for example. This CB control section 47 receives the input signal CEN.
, the output signal CEo with respect to CEE as shown in the following table.
, CEl, and SEL are output.

〔table〕

That is, when the communication enable signal CEM of the 2 active system is "1'," the communication enable signal CEo of "1" is sent to the active system line set unit 61, and the communication enable signal CEI of "0" is sent to the backup system line center atS62. When the communication enable signal CE11 of the active system is "0", a communication enable signal CE of "1" is sent to the standby system line set section 62, but when the communication enable signal CEM and CHE of 1 communication enable signal are both "0", the communication enable signal CE is sent. Both CEo and CE1 are “0”
shall be.

The operation of the embodiment device will be explained below.

- In the redundant line sets 61 to 6n, the active line center section 61 and the standby line set section 62 are assigned the same time slot and internally perform exactly the same operations.

On the other hand, the line set section currently in use is the redundant control device 6.
If the active line set unit 61 is not in a failure state, the active line set unit 6
1 is selected by the duplex control device 63 as the device currently in use.

That is, when the active system line set section 61 is normal, the communication enable signal CEo is "l", the communication enable signal CE1 is "O", and the iJJ system line set section 61 is in a communication enabled state.
The standby line set unit 62 becomes communicable.

In this case, the selector 43 is also switched to the active system line set section 61 side by the selector signal S E l-,
8+! The received data from the line set section 6I is sent to the data terminal 7.

If a failure occurs in the active line set unit 61, this will be detected by the failure detection 11131 in the active line set unit 61.
N, and an alarm flag is set in the alarm register 32N. Microbe L] The processor 5 reads the dirt and sets the communication enable signal CEN to the active system line set section 61 to "0".

As a result, the CB control unit 47 outputs a communication enable signal CE.

As a result, the active line set section 61 becomes in a state where it is unable to transmit.

On the other hand, the standby system line center section 62 becomes communicable information by receiving the communicable enable signal CE of "1". At the same time, the selector 43 is switched to the standby line center section 62 side. Therefore, from then on, communication between the data terminals is performed by the standby line set section 62.

Note that there is also a failure in which the communication enable signal CE does not become "0", but in this case, the network monitoring process connected to the central monitoring node 81 sends the communication enable signal CEN of the current line set of the node. By inputting a command to turn off "01" or by pulling out the current line set circuit board of the relevant node from the device.

It is possible to switch the active line center to the standby line center.

Various modifications are possible in implementing the invention. For example, in the above-described embodiment, all line sets in a node have a duplex configuration, but this is not limited to this, and only the line center for one important data terminal has a duplex configuration, It is also possible to limit the number of nodes equipped with dual configuration lines to some nodes in the network.

Also, the network format is not limited to the ring type.

It may be a bus network LAN, etc., or a multi-line In
It is also possible to use the device of the present invention as a unit 7) for connecting a terminal device to a line multiplexing device in a network in which devices are arranged facing each other.

〔Effect of the invention〕

According to the present invention, the series λ of a terminal connection device such as a line set
In the event of a failure, it is possible to quickly perform failure recovery processing and restore communication between terminals, while limiting the effects of failure recovery to only the failed line without affecting other lines, making the network highly reliable. be able to.

4. Fi of the drawing? i car explanation FIG. 1 is a diagram explaining the principle of the present invention.

FIG. 2 is a block diagram of a node configured using an embodiment of the present invention.

FIG. 3 is a block diagram showing a dual line hint as an embodiment of the present invention.

FIG. 4 shows an example of the configuration of the CB control unit in the embodiment device. FIG. 5 shows a ring type LAN using a line center. FIG. 6 is a block diagram of a conventional example of a line set.

and FIG. 7 is a diagram showing a LAN using conventional duplex configuration nodes.

In fig.

l Repeater 3 Data multiplexer 4 Multiplexer 5 Microprocessor 6, ~6n Duplex line cent 7, ~7n - Data terminal 21.24.41.45 Receiver 22 Parallel/serial conversion circuit 2644.46 driver Serial/parallel conversion circuit Timesloft Kaunk timeslot register comparator AND gate Fault detection circuit alarm register selector CE control section inverter Current line 7th section Reserve line set section Duplex II control device Communication available signal Communication enable signal for active line set section Communication enable signal for standby system line center section +-Takumoe 1 Double 14 Barrel Narinomikoyo 5LAN

Claims (1)

[Claims] Active and standby terminal connection devices (91, 92) for connecting a terminal (95) to a line, and failure detection for detecting the occurrence of a failure in the active terminal connection device (91). circuit (93), and switches the terminal connection device in use from the active terminal connection device (91) to the standby terminal connection device (92) when a failure in the active terminal connection device is detected by the failure detection circuit (93); A highly reliable terminal connection device comprising a switching control circuit (94).