JPH069355B2 - Loop network - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loop type network having a dual transmission path, and particularly when a failure occurs, it converts a failure part without interrupting communication during normal operation. In this case, the present invention relates to a preferable network configuration.

[Background of the Invention]

In a conventional network with a dual transmission line, the same unit of transmission unit and reception unit is the same exchange unit (often a board).
It was housed inside. Therefore, if the transmission line is in a loop back (folded) state due to a failure of the transmitter or the receiver, if you try to replace the replacement unit (unit) that includes the failed part, either the transmitter / receiver in that unit will be replaced. However, there is a drawback in that the faulty part cannot be replaced unless the loop back is made one node before, and the number of terminals that can be operated is reduced for parts replacement. Hereinafter, the problems of the prior art will be described in detail with reference to FIGS. 1 to 4.

FIG. 1 is a general schematic diagram of a loop type communication network having dual transmission lines 101 and 102, in which a telephone 121 or a node device 110, 111, 112, 113 ... The data terminal 122 and the like are connected. Normally, only one of the two transmission lines
(Indicated by the solid line in the figure) and one system is the standby system (dotted line)
And

The node device 110 and the like are repeater units 131 and 132 for exchanging signals on the transmission line and signals in the node device, and a common control unit for exchanging signals exchanged by the repeater units with signals from respective telephones and terminals. It consists of 201.

The repeater unit is usually duplicated, and a specific example thereof is shown in FIG. The repeater unit is roughly divided into transmission units 141 and 142 and reception units 151 and 152, and a transmission signal from the common control unit 201 is transmitted to the transmission unit 1 via the transmission selector 161.
The output signals from 41 and 142 and from the reception units 151 and 152 are sent to the common control unit 201 via the reception selector 162. Each selector is controlled by the loop mode control signal LPMD from the common control unit 201. In this description, the selectors 161 and 162 are referred to as the repeater unit 131,
Although it has been described as being placed outside the 132, it is functionally the same when placed inside the repeater section.

In the conventional technology up to now, the repeater unit 131 connected to one transmission system, for example, the transmission line 101, is configured by a set of a transmission unit 141 and a reception unit 151.

Therefore, when a failure occurs in a part of the transmission system on one side, for example, the transmission unit 141 connected to the transmission path 101, the loop system switches the active system and the standby system as shown in FIG. (Transmission path replacement, loop replacement) By operating the transmission system 102 and replacing the repeater unit 131 including the transmission unit 141 in which a failure has occurred, maintenance can be performed without interruption of communication for a long time.

However, as shown in FIG. 4, when a part of different transmission systems fails at two or more locations at the same time, the loop system causes failure (the receiving system of the repeater unit 134 of the node device 111 and the node device in this case). 113 repeater section 1
A loop not including the 37 receiving system) is reconstructed by loopback (loop back). At this time, however, the structure of the repeater unit has the following problems.

That is, taking the repeater 134 in FIG. 4 as an example, since the receiving system in the repeater unit 134 has a failure, the entire repeater unit 134 must be replaced.
However, of these, the transmission system is used for the loop back of the node device 111, and if the repeater unit 134 is removed for replacement, the loop back at the node device 111 becomes impossible and only one node is separated from the fault position. You will have to loop back with. In this case, all the terminals connected to the node device 111 are incapable of communication, and in the case of a loop system with a small number of nodes, the number of nodes that can operate is 2 on both sides where the loop back is
However, the decrease in the number of functions will greatly reduce the essential functions of the communication system.

[Object of the Invention]

An object of the present invention is to provide a configuration of a loop network in which a node device having a transmission line in a loop back state can replace a transmitting / receiving unit in which a failure has occurred while maintaining a communication function. It is in.

[Outline of Invention]

To achieve the above object, in the present invention, when the transmission line is in the loop back state, attention is paid to the fact that the transmission line is always formed by a combination of the transmission unit and the reception unit belonging to different exchange units, and It is characterized in that the transmitters and receivers of different transmission line systems are combined to form one exchange unit for maintenance.

Example of Invention

An embodiment of the present invention will be described below with reference to FIG. Repeaters 131 and 132, transmission lines 101 and 102, transmitters 141 and 142 connected to each transmission system, and receivers 151 and 1
The functions of 52, the transmission selector 161, and the reception selector 162 are as described above. In the present invention, compared to the conventional example of FIG. 2, the combination of the transmitter / receiver units constituting the repeater unit is different. That is, one repeater unit 131 includes a transmitter 141 for the active transmission line 101 and a standby transmission line 1
02, the other repeater unit 132 includes a receiving unit 152 from the transmission line 101 and a transmitting unit 142 to the transmission line 102.

The effect of this embodiment is shown in FIG. 6 as compared with the case where a part of two different transmission systems simultaneously fails at two or more places as shown in FIG. In this embodiment, since the repeater units 134 and 137 including the faulty part are not the repeater units constituting the loop back, they can be replaced, the maintainability is improved as compared with the conventional example, and the fault countermeasure (part replacement) is performed. ), The number of nodes / terminals that can communicate increases.

[Effect of the Invention] According to the present invention, when two or more faults occur in different transmission systems, the faulty part can be exchanged without affecting the transmission system in the loop back state, thus increasing the operating rate of the communication network. , Has the effect of improving maintainability.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a loop network, FIG. 2 is a connection diagram of a repeater unit and a transmission line by a conventional method, FIGS. 3 and 4 are explanatory diagrams of replacement and loop back by a conventional method, and FIG. Is a connection diagram between a repeater unit and a transmission line according to the method of the present invention, and FIG. 6 is an explanatory diagram of a loop back according to the method of the present invention. 101, 102 ... Transmission path, 110, 111, 113 ... Node device, 131, 138 ... Repeater section, 141, 142
... Sending unit, 151,152 ... Receiving unit.

Claims (1)

[Claims] 1. In a loop-type network in which a plurality of node devices are connected by loop-shaped first and second transmission lines having signal transmission directions opposite to each other, each node device (110-113) comprises: A first repeater unit (132) including a first receiving circuit (152) for receiving a signal from one transmission line (101) and a first transmitting circuit (142) for transmitting a signal to the second transmission line. ) And a second receiving circuit (151) for receiving a signal from the second transmission line (102) and a second transmitting circuit (141) for transmitting a signal to the first transmission line. A repeater unit (131), a control unit (201) for controlling transmission and reception, a reception selector circuit (162) connected between the first and second reception circuits and the control unit, First and second transmission circuits and the above control And a transmission selector circuit (161) connected between the control unit (201) and the control unit (201), which normally receives a signal from the first reception circuit and transmits a signal to the second transmission circuit. When each of the selector circuits is controlled so that communication is performed by the transmission system including the first transmission line, and a failure occurs in the transmission system including the first transmission line, the second receiving circuit is used. The state of each of the selector circuits is switched so as to receive a signal and send the signal to the first transmission circuit, and communication is performed by the transmission system including the second transmission line, and the transmission system including the first transmission line. When a failure occurs in both of the transmission system including the above and the second transmission path, and any one of the failures is caused by any one of the first and second repeater units in the own node device, a normal state In the repeater section of any one of the first and second Receiving a signal from the first receiving circuit and transmitting a signal to the first transmitting circuit
The state of each selector circuit is switched so as to perform loopback or a second loopback in which a signal is received from the second receiving circuit and a signal is transmitted to the second transmitting circuit, and the communication function of the node device is maintained. A loop-type network characterized in that the repeater unit on the faulty side can be replaced without changing.