JPH04137842A - Fault location identification system for ring communication system - Google Patents

Abstract

PURPOSE:To identify a fault location when a fault takes place in an optical fiber transmission line of an upperstream of a station by providing a specific function to each of a line concentrator and the station. CONSTITUTION:A line concentrator 12 is provided with a non-signal state detection circuit 31a, a changeover circuit 32 and a fault notice signal generating circuit 33 as a function of monitoring a broken ring optical fiber transmission line 11 and supplying a fault notice signal to a station 13 through an optical fiber transmission line 22 in place of a data signal when the line 11 is broken. On the other hand, the station 13 is provided with a non-signal state detection circuit 31b and an AND circuit 34 as a function of monitoring a broken optical fiber transmission line 22 and eliminating a data signal to the line concentrator 12 when the line 22 is broken. Thus, whether a fault location caused on the station is an optical fiber transmission line between the line concentrator and the station or a ring optical fiber transmission line is surely identified.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fault location identification method for identifying a fault location in an optical fiber transmission line that occurs in a ring communication system using optical fibers for the transmission line. .

[Prior Art] FIG. 2 shows the configuration of a ring communication system using optical fibers.

Line concentrators 12a to 12d are provided in the middle of the ring optical fiber transmission line 11 constituting the ring 10, and a plurality of stations 13a to 13h are connected to them by optical fiber transmission lines (hereinafter referred to as branch lines) 21 and 22. 1
Station 13a to ring 10 by 2a-12d
This is a configuration that performs addition and removal of 1M for ~13h. Each concentrator 1
A relay 23 is provided inside 2a to 12d,
By this relay 23, each station 13a to 13h
can freely join and leave the ring 10.

When 10 joins the ring, the station that wants to join, for example, station 13a, joins the line concentrator 12a to which it belongs.
This is done by transmitting a specific optical pattern signal to the target. Line concentrator 1 that detected a specific optical pattern signal
2a switches the internal relay 23 to join the station 13a to the ring.

Detachment from the ring 10 is performed by the station from which the detachment is desired, for example, the station 13a, stops outputting optical data signals for a certain period of time or more.

The line concentrator 12a detects this no-signal state, and the relay 2
3 to detach the station from the ring 10. As a result, if the optical fiber transmission line (branch line) 21 that transmits the optical data signal from the station to the line concentrator is disconnected, for example, as shown by the X mark in FIG. When the branch path 21a is disconnected among the branch paths 21a, 22a, 21b, and 22b existing in the ring 10, the line concentrator 12a detects the no-signal state and switches the corresponding relay 23a of the relays 23a and 23b.
The fault location can be isolated from the

[Problems to be Solved by the Invention] However, the above-described conventional technology has the following drawbacks. That is, if a failure occurs in the optical fiber transmission line upstream of the station while the station is in the joined state, the station will be able to detect the failure in the optical fiber transmission line that carries data from the concentrator to the station, as shown in FIG. There was a problem in that it was not possible to identify whether the occurrence occurred on the line 22b (point A) or the ring optical fiber transmission line 11 (point B).

An object of the present invention is to eliminate the drawbacks of the prior art described above, and to identify whether the failure location is at point A or point B when a failure occurs in the optical fiber transmission line upstream of a station. The purpose of this invention is to provide a fault location identification method that enables

[Means for Solving the Problems] The fault location identification method of the present invention is a ring communication system consisting of a line concentrator equipped with a station insertion/disconnection mechanism, a station, and an optical fiber transmission line. has a function that transmits an abnormality notification signal to the station when the data signal from the ring optical fiber transmission line disappears for a certain period of time, and the station immediately transmits the data signal when it detects that the data signal disappears for a certain period of time or more. It has the function of stopping.

"Function" If a fault such as a disconnection occurs in the ring optical fiber transmission line among the upstream optical fiber transmission lines, the concentrator detects the fault and notifies the station of this with an abnormality notification signal.On the other hand, Among the upstream optical fiber transmission lines, if a failure such as a disconnection occurs in the optical fiber transmission line (branch line) that conveys data signals from the concentrator to the station, the data signal to the station side will be lost, and the station will It detects this and leaves the ring.Therefore, if the fault is in the ring optical fiber transmission line (B
It is possible to identify whether the problem occurred at the optical fiber transmission line from the concentrator to the station (point A).

[Example] Embodiments of the present invention will be described below with reference to FIG.

FIG. 1 shows the configuration of a transmitting and receiving circuit between one station and one concentrator to which it belongs. Here, a transmitting/receiving circuit between the station 13 and the line concentrator 12 is typically shown.

In the case of the embodiment shown in FIG. 1, the line concentrator 12 has the function of monitoring the ring optical fiber transmission line 11 for disconnection, and when the line is disconnected, sends an abnormality notification signal instead of a data signal to the optical fiber transmission line 22 to the station. No signal state detection time H31
a, a switching circuit 32 and an abnormality notification signal generation circuit 33. On the other hand, the station 13 is connected to the optical fiber transmission line 2.
It has a no-signal state detection circuit 31a and an AND circuit N34 as a function of monitoring wire breakage of the line 2 and erasing the data signal to the line concentrator when a wire breakage occurs. The line concentrator 12 also has the function of monitoring the optical fiber transmission line 21 for breakage and disconnecting the station 13 from the ring 10 when the line breaks.
It has a no-signal state detection circuit 31c and a relay drive circuit 35. Note that 36a and 36b are Elo (electrical/optical) converters.

37a and 37b are O/E (optical/electrical) converters.

Next, the operation will be explained.

(1) When a disconnection occurs in the upstream ring optical fiber transmission line 11, the data signal to the line concentrator 12 is lost. Therefore, the no-signal state detection circuit 31a on the line concentrator 12 side detects the disappearance of the data signal for a certain period of time or more, and sends a signal to the signal switching circuit 32 and the abnormality notification signal generation diagram 833. The abnormality notification signal generation circuit 33 generates an abnormality notification signal based on the signal from the no-signal state detection circuit 31a. Further, the signal switching port 1i32 switches the data signal from the ring optical fiber transmission #111 to the abnormality notification signal from the abnormality notification signal generation circuit 33 based on the signal from the no-signal state detector 831a. This abnormality notification signal is sent to the station 13 side via the E10 converter 36a.

The station 13 receives an abnormality notification signal sent from the optical fiber transmission line 22 from the line concentrator 12 via the O/E converter 37b, thereby detecting that a disconnection has occurred in the upstream ring optical fiber transmission line 11. You can know that.

Note that if there is a break in the ring optical fiber transmission line 11, the signal on the optical fiber transmission line 22 only changes from a data signal to an abnormality notification signal, and the signal still exists, so the station 131111 The no-signal state detector 31b does not operate.

(2) If the optical fiber transmission line 22b that transmits data from the line concentrator 12 to the station 13 is disconnected, the data signal on the optical fiber transmission line 22 disappears. When the signal on the optical fiber transmission 8822 disappears for a certain period of time or more, the no-signal state detection circuit 31b of the station 13fllJ detects it, sends a "Low" signal to the AND circuit 34, and stops transmitting data to the line concentrator 12. .

This allows optical fiber transmission F! from station 13 to concentrator 12. ? ! The data signal on 21 disappears. In the line concentrator 12 (1!), the no-signal state detection circuit 31c
Detects this no-signal state for a certain period of time or more and drives the relay F! Send signal to @35 and move station 13 to ring 1
Detach from 0.

According to the above embodiment, whether the failure point occurring upstream of the station is the optical fiber transmission line 21, 22 (point A) between the concentrator 12 and the station 13, or
Is it the ring optical fiber transmission line 11 (point B)?
This can be reliably identified, and if the optical fiber transmission lines 21, 22 are broken, the station 13 can be removed from the ring 10, thereby quickly separating the faulty location from the ring.

[Effects of the Invention] According to the present invention, it is possible to determine whether a fault that occurred upstream of a station occurred on the optical fiber transmission line (point A) that transmits data from the concentrator to the station, or whether it occurred on the ring optical fiber transmission line (point B). It is possible to identify whether it has occurred. Furthermore, in the event that the optical fiber transmission line that transmits data from the line concentrator to the station is disconnected, the station can be removed from the ring, thereby quickly separating the faulty location from the ring.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a transmitting/receiving circuit between a station and a line concentrator according to an embodiment of the present invention, Fig. 2 is a network configuration diagram, and Fig. 3 is a diagram of a conventional system when a break occurs in an optical fiber transmission line. It is an explanatory diagram. In the figure, 10 is a ring, 11 is a ring optical fiber transmission line,
12.12a ~ 12d are concentrators, 13.13a ~
13h is a station, 2121a and 21b are optical fiber transmission lines that transmit data from the station to the concentrator,
22゜22a, 22b are optical fiber transmission lines for transmitting data from the concentrator to the station; 23゜23a, 23
b is the line concentrator! Internal relays, 31a31b, 31c are no-signal detection circuits, 32 is a signal switching circuit, 33 is an abnormality notification signal generation circuit, 34 is an AND circuit, 35 is a relay drive circuit,
36a. 36b is an E10 converter, and 37a and 37b are O/B converters.

Claims (1)

[Claims] 1. In a ring communication system consisting of a concentrator equipped with a station insertion/disconnection mechanism, a station, and an optical fiber transmission line, the data signal from the ring optical fiber transmission line is lost to the concentrator for a certain period of time or more. A ring communication system characterized in that the station is provided with a function of sometimes transmitting an abnormality notification signal to a station, and the station is provided with a function of immediately stopping transmission of the data signal upon detection of disappearance of the data signal for a certain period of time or more. Fault location identification method.