JP2876908B2 - Transmission path failure notification method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission line fault notifying system, and more particularly to a transmission line fault notifying system for a network comprising a plurality of time-division multiplexers.

[0002]

2. Description of the Related Art In a conventional transmission line fault notification system, when a fault occurs on a high-speed line of a network, an interface of the high-speed line to which the line is connected detects the fault.
The interface of the high-speed line converts the data into a specific pattern (signal) for notifying all failures. The converted signal is
The data is transferred to a low-speed line interface or a high-speed line interface via the T switch. The low-speed line interface has a circuit for detecting a specific pattern, and when a specific pattern for notifying a failure is detected, it is determined that the high-speed line has a failure.

[0003]

In the above-described conventional transmission path failure notification method, when a failure is detected, the content of the signal is changed to a specific pattern, so that normal data may be the same as the pattern for reporting the failure. It is impossible to determine whether a failure has occurred. in this way,
There is a problem that normal data may be determined to be a failure notification. Further, in the case of a communication error due to a failure in a line not accommodated by the own station, the failure location could not be specified.

[0004] It is an object of the present invention to provide a transmission path fault notification method for notifying a fault in a remote transmission path without losing the transparency of the transmission path and specifying a fault location.

[0005]

According to the transmission line failure notification method of the present invention, in a network composed of a plurality of time-division multiplexing apparatuses, a normal pattern indicating that data is normal at a low-speed line interface. A normal pattern generation circuit that generates the error, a comparison circuit that compares the normal pattern with a failure notification signal in the data transmitted on the high-speed line, and notifies the control unit of the result. An abnormal pattern generating circuit for generating an abnormal pattern indicating that there is a selector circuit for selecting whether the abnormal pattern or data transmitted on a high-speed line by a fault notification, and detecting a fault of the connected high-speed line and A fault detection circuit for sending a fault notification to the control unit, and an output of the comparison circuit of a plurality of low-speed line interfaces in the device. It receives the output of the fault detection circuit of the interface of the plurality of the high-speed line, specifying the failure location by sending and receiving failure information between the control unit of another time division multiplexer in the network.

[0006]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a time division multiplexer according to one embodiment of the present invention.

[0007] The time division multiplexer comprises a plurality of low-speed line interfaces 100 and a plurality of high-speed line interfaces 2.
00, 300, a T switch (TSW) 400 for exchanging time slots, a low-speed line interface 100, a high-speed line interface 200, and a TSW 40.
It has a control unit 500 for controlling and monitoring 0, and accommodates a plurality of high-speed lines 20 and 40 for transmitting multiplexed signals and a plurality of low-speed lines 30 connected to terminals, respectively.

The high-speed line 40 is a high-speed line interface 2
00, the high-speed line 20 is connected to the high-speed line interface 300, and the signal transmitted by the high-speed line 40 is passed to the TSW 400 through the high-speed line interface 200. The TSW 400 exchanges time slots in advance according to the setting by the control unit 500, and passes a signal to another high-speed line interface 300 or another low-speed line interface 100 according to the setting. The high-speed line interface 300 has a high-speed line 20
Are connected, and a signal passed from the TSW 400 is transmitted to the high-speed line 20. The low-speed line interface 100 is connected to the low-speed line 30,
The signal passed from 400 is transmitted by the low-speed line 30.

[0009] As shown in FIG. 2, it is assumed that a plurality of time division multiplexing devices and a terminal device are connected. The time-division multiplexing devices 12 and 17 include a high-speed line 90,
13 is a high-speed line 50, time-division multiplexers 13 and 14 are high-speed lines 60, and time-division multiplexers 17 and 18 are high-speed lines 9
1. The time-division multiplexers 18 and 14 are connected by a high-speed line 92, the terminal device 15 and the time-division multiplexer 12 are connected by a low-speed line 80, and the terminal device 16 and the time-division multiplexer 14 are connected by a low-speed line 70.

Each time-division multiplexing device 12, 13, 14, 1
As described above, the high-speed lines 40 and 20 for transmitting the multiplexed data and the low-speed lines 30 connected to the terminal device are accommodated in the switches 7 and 18, and the TSW 400 exchanges data. Now, it is assumed that communication is performed between the terminal devices 15 and 16 using the high-speed lines 90, 50 and 60. In the low-speed line interface 100, the pattern generated by the normal pattern generation circuit 1 and indicating that the transmission path is normal is transmitted as a failure notification signal. .. 010101... By the path control circuit 3.
The pattern and the data to be transmitted are multiplexed so as to enter the same multi-frame, and pass through the same route. The data and the failure notification signal are loaded on the high-speed line 40 via the high-speed line interface 200 by the TSW.

In the high-speed line interface 200, the failure detection circuit 8 determines whether or not there is a failure in the high-speed line 40 from the received data including the failure notification signal transmitted on the high-speed line 40. If no failure is detected, the received data is selected by the select circuit 6, and the received data is passed to the TSW. This received data is TSW
Is passed to the low-speed line interface 100 or the high-speed line interface 300. In the low-speed line interface 100, the received data is separated by the separation circuit 4 into data and a failure notification signal. The comparison circuit 2 compares the separated fault notification signal pattern with the... 010101... Pattern generated in the normal pattern generation circuit 1, determines whether the received data is normal or abnormal, and notifies the control unit 500. I do.

On the other hand, when a fault is detected by the fault detecting circuit 8, the... 111111... Pattern generated by the abnormal pattern generating circuit 7 is selected in response. The failure detection is notified to the control unit 500. The abnormal pattern generation circuit 7 is a circuit that generates a pattern... 111111... Pattern indicating that a failure in the high-speed line 40 has been detected.
In this case,... 111111.
Is passed from the low-speed line interface 100 to the high-speed line interface 300. In the low-speed line interface 100, the received data is separated into data and a failure notification signal by the separation circuit 4, and the comparison circuit 2 determines whether the data is normal or abnormal by the method described above, and notifies the control unit 500.

The control unit 500 receives the output of the comparison circuit 2 of the low-speed line interface 100 and the output of the fault detection circuit 8 of the high-speed line interface 200, and outputs the result of comparison of the fault notification signal of the low-speed line interface 100 of its own station. (Output of comparison circuit 2) and high-speed line interface 2
00 is detected (output of the failure detection circuit 8). If a fault in the transmission path is detected, it is understood that a fault has occurred in the high-speed line to which the high-speed line interface is connected. If the output of the comparison circuit 2 determines that the data is abnormal and no fault in the transmission path is detected, it is likely that a fault has occurred somewhere on the high-speed line in the middle of the transmission path, which is not accommodated by the own station. It turns out to be the cause. The control unit 500 is in communication with the control unit of another station, and the time division multiplexing device 12 performs the time division multiplexing except when all the high-speed lines accommodated by the time division multiplexing device 12 fail. It is possible to know the states of the devices 13, 17, 14, and 18.

As shown in FIG. 2, it is assumed that transmission is performed between the terminal devices 15 and 16. Time division multiplexer 12
Reference numerals 13, 14, 17, and 18 are time-division multiplexing devices shown in FIG. It is assumed that a failure occurs in the high-speed line 60 shown in FIG. 2 and communication between the time-division multiplexers 13 and 14 becomes impossible. At this time, assuming that the signal is received by the high-speed line interface 200 in the time division multiplexer 14, the failure detection circuit 8 detects that a failure has occurred in the high-speed line 40 connected to the high-speed line interface 200. In the time-division multiplexing device 13, if the signal is received by the high-speed line interface 200, the failure detection circuit 8
Detects that a failure has occurred in the high-speed line 40 connected to the high-speed line interface 200. In response to this, the selection circuit 6 selects not the received data but the... 111111... Pattern from the abnormal pattern generation circuit 7 and passes it to the TSW 400. The TSW400 has this ... 1
11111... Pass the pattern to the high-speed line interface 300 as transmission data. High-speed line interface 30
0 is transmitted to the high-speed line 20 connected as one of the multiplexed signals. In FIG. 2, the high-speed line is a high-speed line 50.

In the time division multiplexer 12, it is assumed that the signal is received by the high-speed line interface 200 shown in FIG. High-speed line 4 connected to high-speed line interface 200
0 (in FIG. 2, the high-speed line 50), no failure has occurred, so the select circuit 6 selects the received data and
Pass to 00. The TSW 400 passes the received data to the low-speed line interface 100. Since the received signal is a signal in which the failure notification signal and the data are multiplexed in the same multiframe by the path control circuit 3, the separation circuit 4
Thus, the data and the failure notification signal can be separated. The comparison circuit 2 receives the failure notification signal and the normal pattern generation circuit 1
Indicates that the transmission path is normal by 010101 ...
Compare patterns. The received signal is ... 111111
... Pattern, it can be determined as a result of the comparison that a failure has occurred somewhere on the transmission path through which this data was transmitted.

As described above, when a failure occurs in the high-speed line 60 in FIG. 2, it is possible to notify the time-division multiplexing device 12 of the failure in the middle of the transmission path without the possibility of correct data. The comparison circuit 2 notifies the control unit 500 of the detection result. Since no failure has occurred in the high-speed line 40 (the high-speed line 50 in FIG. 2) connected to the high-speed line interface 200 in the time-division multiplexing device 12, the control unit 500 has abnormal data in the comparison circuit 2. Is received, and its own station is not accommodated. It can be seen that the cause is that a failure has occurred somewhere on the high-speed line in the middle of the transmission path.

On the other hand, in the control unit 500 of the time division multiplexing device 13 and the time division multiplexing device 14, the failure detection circuit 8 indicates that a failure has occurred in the high-speed line 60. The control unit 500 of the time division multiplexing device 13 notifies the time division multiplexing device 12 that a failure has occurred in the high-speed line 60 via the control unit 500 of the time division multiplexing device 17. In this way, the time division multiplexing device 12 can obtain information that the detected fault in the middle of the transmission path has occurred in the high-speed line 60.

[0018]

As described above, according to the present invention, the failure notification signal different from the data to be transmitted is transmitted using the same transmission path as the data, and the failure of each node transmitted through the different transmission path is transmitted. By using the information to specify the location of the failure, the failure can be transmitted without losing the transparency of the transmission path, and the direct communication between the control units allows the location of the failure on the remote line to be identified.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is a block diagram illustrating connection of a plurality of time division multiplexing devices according to the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Normal pattern generation circuit 2 Comparison circuit 3 Bus control circuit 4 Separation circuit 6 Select circuit 7 Abnormal pattern generation circuit 8 Fault detection circuit 500 Control unit

Claims (1)

(57) [Claims] 1. A normal pattern generating circuit for generating a normal pattern indicating that data is normal at an interface of a low-speed line in a network constituted by a time division multiplexer of a plurality of stations; A comparison circuit that compares the failure notification signal in the data transmitted on the line and notifies the control unit of the result, and an abnormality pattern generation circuit that generates an abnormality pattern indicating that the data is abnormal on the high-speed line interface. A selector circuit for selecting between the abnormal pattern and data transmitted on a high-speed line based on a failure notification, and a failure detection circuit for detecting a failure of the connected high-speed line and sending the failure notification to a control unit. And output of the comparison circuit of the plurality of low-speed line interfaces in the apparatus and fault detection of the plurality of high-speed line interfaces A transmission path failure notification method, comprising: receiving a circuit output; and transmitting / receiving failure information to / from the control unit of another time-division multiplexing device in the network to identify a failure location.