JPH0564894B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a polling monitoring method in an optical transmission system using a CMI (corded mark inversion) frame as a transmission path code. In the case of polling, a method is used in which a monitoring signal is constantly sent to each relay station or terminal station one by one, and the station receiving the monitoring signal sends alarm information and the like of its own station back to the monitoring device.

〔overview〕

The present invention relates to a monitoring method using polling used in an optical communication system that is connected to a partner terminal station via a repeater and in which CMI-encoded main information is exchanged between the terminal stations. By assigning signal bits related to the polling of each end station to different bits of the sub information frame generated based on the violation of the Even if the transmitted transmission line is disconnected, remote monitoring of the repeater can still be performed reliably.

[Conventional technology]

FIG. 3 shows a conventional monitoring system. Although a plurality of relay stations are connected, the drawings show only one of them in a simplified manner. In the conventional method, the main signal transmission line 5
A transmission path 60 for the monitoring signal is provided separately from the terminal station 0, and one of the terminal stations is used as the master station (terminal station A in Fig. 3), and the monitoring signal is returned from the master station side in the direction shown by the broken line to perform polling. I was gone.

[Problem that the invention seeks to solve]

However, such a conventional system has a problem in that a separate line must be provided for the monitoring signal. By the way, when the transmission line code is a CMI code,
It is possible to superimpose sub information on the main signal and transmit it by using violation of the CMI coding rule, and by configuring the frame with bits (OH bits) on which this sub information is superimposed, multiple pieces of sub information can be superimposed. can do. This method eliminates the need to provide a separate line for supervisory signals. The line configuration in this case is shown in FIG. However, since the supervisory signal is transmitted on the same line as the main signal, simply changing the supervisory signal transmission line in Figure 3 to an OH bit will not allow the main signal line to reach point C in Figure 4. In case of disconnection,
A drawback arises in that polling cannot be used to monitor adjacent relay stations and stations beyond that. In the conventional system, such a problem did not occur because the lines were different.

In the present invention, when a main signal line disconnection accident occurs at point C in FIG. The purpose is to provide a monitoring method that can be used.

[Means for solving problems]

The present invention relates to a monitoring method in which a repeater inserted into a transmission path through which CMI-encoded main information is transmitted is monitored by a polling method from an end station connected to this transmission path. The repeater allocates the signals to different predetermined bits of a sub information frame generated based on a coding rule violation associated with CMI encoding of the main signal, superimposes them on the main signal, and transmits them, and the repeater transmits the above signals specifying its own station. When a supervisory signal is extracted, a coding rule violation associated with CMI encoding is performed on the main signal of the transmission path in the opposite direction, and the supervisory information is returned.

[Effect]

When the transmission path is healthy, both end stations monitor the relay station by polling.

In this case, the polling signal bit is the main information.
It is assigned to a predetermined bit of a sub-information frame generated based on a violation of the CMI encoding rule, depending on the terminal station. Therefore, no collision of polling signal bits occurs.

Since this sub-information is superimposed on the main information, the transmission path through which the main information is transmitted can be used as the transmission path.

Furthermore, even if a transmission line connected to one terminal station is disconnected, for example, it can be monitored from the other terminal station.

〔Example〕

Hereinafter, an embodiment of the present invention will be explained based on the drawings.

First, a case in which terminal station 1 polls relay station 3 will be described. Monitoring device 11 of terminal station 1
The monitoring signal 100 sent from the CMI encoder 1
2, the signal is superimposed on the main signal 110, CMI encoded, and converted into an optical signal 120, which is then sent to the optical transmission line 4. At the relay station 3, after being converted into an electrical signal, the CMI decoder 25 separates it into a main signal 110 and a supervisory signal 100, and the supervisory signal 100 is sent to the SV device 2.
1. The SV device 21 determines that the inquiry is directed to its own station, and sends a monitoring signal 105 containing alarm information for its own station to the CMI encoder 22 on the optical transmission path 7 on the opposite side. In the CMI encoder 22 , the supervisory signal 105 is superimposed on the main signal 250 from the terminal station 2 and sent to the terminal station 1 as a CMI-encoded optical signal 125 . At the terminal station 1, the optical signal 125 from the relay station 3 is converted into an electrical signal, and the monitoring signal 105 is separated and sent to the monitoring device 11. At this point, the transmission and reception after the monitoring signal 10 is completed.

When polling is performed from the terminal station 2 to the relay station 3, everything is the same as above except that the OH bit used is different.

In addition, as shown in FIG. 2, under normal conditions where there is no failure such as disconnection in the transmission line 50, terminal station A and terminal station B
monitoring by polling from both sides.
That is, a path 55 indicates a return route for the monitoring signal from the terminal station A, and a route 56 indicates a return route for the monitoring signal from the terminal station B. Returning is performed only for the OH bit on which the monitoring signal is superimposed. At the relay station, the monitoring signals from both end stations are superimposed and different OH bits are used, so there is no possibility of the monitoring signals colliding at the relay station.

〔Effect of the invention〕

As explained above, the present invention not only enables monitoring using the main signal transmission line, but also uses the same line as the main signal line for polling from both terminal stations. This has the effect of completely eliminating the need for a supervisory signal line.

Another advantage is that monitoring can be performed while the main signal is being transmitted.

[Brief explanation of drawings]

FIG. 1 is a block configuration diagram showing the configuration of a monitoring system in which the method of the present invention is used. FIG. 2 is an explanatory diagram showing the operation of the monitoring method of the present invention. FIG. 3 is an explanatory diagram showing the operation of the conventional monitoring method. FIG. 4 is an explanatory diagram showing the operation of a monitoring method that is an improved conventional method. 1, 2... Terminal station, 3... Relay station, 4-7... Optical transmission line, 11, 31... Monitoring device, 12, 22,
26, 32...CMI encoder, 13, 23, 27,
33...Electric-optical converter, 14, 24, 28, 3
4...Optical-electrical converter, 15, 25, 29, 35
...CMI decoupler, 21 ...SV device, 50,60
...Transmission line.

Claims (1)

[Claims] 1. In a monitoring method in which a repeater inserted in a transmission path through which CMI-encoded main information is transmitted is monitored by a polling method from an end station connected to this transmission path, both end stations The repeater assigns the supervisory signal to be transmitted to different predetermined bits of a sub-information frame generated based on a coding rule violation associated with CMI encoding of the main signal, superimposes it on the main signal, and transmits it. When the above specified monitoring signal is extracted, CMI is added to the main signal of the transmission path in the opposite direction.
A monitoring method characterized in that the above-mentioned monitoring information is returned by violating a coding rule associated with encoding.