JPH0879171A - In-device monitoring method - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an in-device monitoring method capable of identifying a failure position of a transmission system in a short time. [Structure] In an optical transmission device in which the transmission optical fiber transmission line is duplicated and the normal / spare transmission lines both transmit the same data under normal conditions, the back light of the laser diode for data transmission is used to transmit the active and standby interfaces. It has a component for monitoring data matching.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a processing method for a failure inside an optical fiber transmission device.

[0002]

2. Description of the Related Art The following techniques are related to conventional optical fiber transmission devices. In a transmission device adopting a transmission line redundant configuration, a plurality of optical fiber cables are used for the transmission line, and transmission line switching is executed inside the device so that a normal transmission line is used in the case of a failure such as disconnection of the optical fibers. However, it is a general failure countermeasure method. FIG. 3 is a diagram showing an outline of the configuration of the above conventional system.
1, 101a are working transmission line interface circuits, 10
2, 102a are backup transmission line interface circuits, 10
3, 103a is an intra-office interface circuit, 104 is a working optical fiber transmission line connecting the working transmission line interface circuits 101 and 101a, and 105 is a standby optical fiber transmission line connecting the backup transmission line interface circuits 102 and 102a. .

Next, a method of realizing transmission path switching will be described. The in-device signal of the transmitting side transmission device is generated in the in-station interface circuit 103, etc., and is output to the working transmission line interface circuit 101 and the protection transmission line interface circuit 102, and thereafter, the working optical fiber transmission line 104 and the protection optical fiber transmission line, respectively. The same signal is sent to 105 respectively. In the transmission device on the receiving side, the working optical fiber transmission line 1 is used in the working transmission line interface circuit 101a and the protection transmission line interface circuit 102a, respectively.
04, receiving a signal from the spare optical fiber transmission line 105,
In-station interface circuit 103a as a device signal
Send to. Intra-station interface circuit, etc. on the receiving side 10
In 3a, the failure of the transmission path or the failure of the transmission path interface circuit on each of the transmitting side and the receiving side is determined, and when the failure occurs, the signals sent from the working transmission path interface circuit 101a and the standby transmission path interface circuit 102a are selected. As a result, transmission line switching is realized.

However, in the conventional transmission apparatus, since the receiving side only detects the error detecting data such as the CRC bit added at the transmitting side and monitors it, the receiving side can detect the data. When an error is detected, there is a problem that it is difficult to identify a failure location such as whether this data error has occurred in the transmission side transmission line interface or in the transmission line.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems in the prior art as described above and to provide a means for identifying a failure position of a transmission system in a short time.

[0006]

In order to achieve the above object, in the fault monitoring system in the optical fiber transmission device according to the present invention, the transmission optical fiber transmission line is duplicated so that the same data is normally used in both the working and protection transmission lines. An optical transmission device that is being transmitted is characterized by including a constituent element that uses the back light of a laser diode for data transmission and monitors whether or not the transmission data of the working and backup interfaces match.

[0007]

The present invention converts the back light of the working / standby laser diode into an electric signal in an optical transmission device having a dual transmission system and monitors the coincidence of each data.
It is possible to monitor errors for all data sent. The alarm output of this monitoring result has a remarkable effect in identifying a failure position (failure device) of the transmission system in a short time.

[0008]

An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention. The figure shows the configuration on the transmitting station side only. Similar to FIG. 3, 1 is a working transmission line interface circuit, 2 is a backup transmission line interface circuit, 3 is an intra-station interface circuit, etc., 4 is a working optical fiber transmission line, 5
Is a spare optical fiber transmission line, 6 is a distributor, 7 is a transmission signal generation circuit, 8 is an E / O conversion circuit, 9 is a frame synchronization signal generation / addition circuit, 10 is an error check signal generation / addition circuit, and 11 is It is a working / preliminary coincidence monitoring circuit.

The intra-station interface circuit 3 and the like, the working transmission line interface circuit 1 and the backup transmission line interface circuit 2 are connected via a distributor 6, respectively, and the working transmission line interface circuit 1 and the backup transmission line interface circuit are connected. 2 are connected to a receiving station side transmission device (not shown) via the working optical fiber transmission line 4 and the backup optical fiber transmission line 5, respectively.

The active transmission line interface circuit 1 and the backup transmission line interface circuit 2 mainly include a transmission signal generation circuit 7 and an E / O conversion circuit 8. The transmission signal generation circuit 7 has a function of generating / adding a frame synchronization signal (FSYNC) and an error check signal (CRC). On the other hand, the E / O conversion circuit 8 mainly has a function of converting a transmission electric signal into an optical signal by a laser diode (LD) and an automatic power control (controlling the output power of the optical signal by using the back light of the laser diode ( APC) function and so on. Although not shown, a clock circuit for synchronization is commonly referred to and used in each circuit in the station. With this, the timing of data transmission / reception between each circuit / device is measured, and the transmission quality on the transmission path is guaranteed.

Next, the function of each circuit will be described through an actual data transmission operation. First, the same intra-device signal is passed from the intra-station interface circuit 3 to the working transmission line interface circuit 1 and the backup transmission line interface circuit 2, respectively. In-apparatus signals are used for the active transmission line interface circuit 1 and the standby transmission line interface circuit 2.
Then, a frame synchronization signal (F
SYNC) and an error check signal (CRC) are generated and added to form a data frame. The data-framed transmission signal is converted from an electric signal to an optical signal by the E / O conversion circuit 8, and each of the working optical fiber transmission lines 4
Also, the same transmission signal is sent to each of the spare optical fiber transmission lines 5.

Now, paying further attention to the E / O conversion circuit 8, this circuit utilizes the function of converting an electric signal into an optical signal by a laser diode (LD) and the back light of the laser diode as described above. Automatic power control (APC) to control optical output power
It consists of functions. Originally, a commercially available LD has a back light output terminal installed in advance. LD
All the data output from the transmission line to the transmission line is an optical pulse, but back light is generated in the direction opposite to the LD. This can be received by a photodiode (PD), the light pulse can be converted into an electric signal and taken out from this terminal. This is the AP that originally controls the optical output power.
It is used as an input signal to C (see FIG. 2).
However, in the transmission line redundant configuration assumed in this case, since there are two of these, one in each of the working transmission line interface circuit 1 and the standby transmission interface circuit 2, the output signals of these two rear light output terminals are also Two
The system will be generated.

The point of the present invention is to input this into the working / preliminary co-coincidence monitoring circuit 11 and perform collation processing by a method known to those skilled in the art, so that all the data to be transmitted to the optical fiber transmission line can be detected. , Is to monitor bitwise matches. As a result, the transmission data error occurrence can be detected more accurately and more quickly. In the prior art, the transmission signal generation circuit 7 performed memory parity check and error control of transmission data by adding CRC, but the E / O conversion circuit 8 often does not monitor data error. It was

The present invention makes it possible to monitor a wider range of data errors and circuit failures than was possible with the prior art. As for the specific monitoring range, the in-device signal generated from the in-station interface circuit 3 or the like is distributed by the distributor 6
After passing through the transmission signal generation circuit 7 and the E / O conversion circuit 8 through the above, all circuits related to data transmission until immediately before being sent to the working optical fiber transmission line 4 and the standby optical fiber transmission line 5 are targeted.

[0015]

As described above, according to the present invention, the back light of the working / standby laser diode is converted into electricity by the optical transmission device having the dual transmission system and the coincidence of each data is monitored. It is possible to specify at least whether the data error is caused by the transmission path or occurred on the interface side, and it is also possible to specify whether the data error is the working / standby together with the error detection result on the receiving side. Further, if each block in the transmission line interface is provided with a signal monitoring means, for example, a detailed data error such as an error at the time of E / O conversion in an E / O conversion circuit or a disconnection of a pattern wiring connecting the blocks. The occurrence position can be specified. That is, there is a remarkable effect in identifying the failure position (failure device) of the transmission system in a short time.

[Brief description of drawings]

FIG. 1 is a block diagram of a system showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a main part of one embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a system showing an example of a conventional example.

[Explanation of symbols]

1 working transmission line interface circuit, 2 backup transmission line interface circuit, 3 intra-station interface circuit, etc. 4 working optical fiber transmission line, 5 backup optical fiber transmission line, 6 distributor, 7 transmission signal generation circuit, 8 E / O
Conversion circuit, 9 frame synchronization signal generation / addition circuit, 10
Error check signal generation / addition circuit, 11 working /
Pre-coincidence monitoring circuit.

Claims (1)

[Claims] 1. In an optical transmission device in which a transmission optical fiber transmission line is duplicated and both the working / standby transmission lines normally transmit the same data, the backside light of a laser diode for data transmission is used, and a working / standby interface is used. In the optical fiber transmission device, a monitoring method is provided, which comprises a constituent element for monitoring the coincidence of the transmission data.