JP2728040B2 - Fault judging device and judgment method for digital private line network - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for transmitting a failure notification signal of a data terminal on a transmission side and a failure notification signal of a digital leased line network transmitted via a digital leased line network connected to a line switching device on a reception side. The present invention relates to a digital private line network fault determining apparatus and method for detecting and determining the occurrence of a fault.

[0002]

2. Description of the Related Art FIG. 4 shows an example of a conventional fault determination system. Data terminals 42 such as routers and frame relays
PBX41 of time-division switch that accommodates 0,421
In reference numerals 0 and 411, failure notification detection circuits 450 and 451 are provided in digital trunks 440 and 441 which are interfaces to the digital private line network 400. The central monitoring and maintenance center 480 monitors the data communication state by the CPU 481 via an INS switching network different from the digital leased line network 400, and controls the switching of the transmission path.

[0003] Data terminals 420 and 421 and PBX4
10, 411 mutually transmit and receive and each device and its function are symmetrical.
0 as the transmitting side, PBX 410, digital private line network 4
00 and the other data terminal 42 via the PBX 411
1 is described, but the same applies to the case of communication in the reverse direction from the data terminal 421 to the data terminal 420.

The data to be transmitted and the transmission control procedure are sent to the data terminal 421 via the PBX 411 according to the protocol specified in the high-speed digital private line network 400. For example, in the case of high-level data link control (HDLC), "011" is set as a flag before and after data to be transmitted.
11110 "is sent as a frame with a bit string attached thereto. The data of the same pattern as the flag in the frame is used at the time of frame assembly in order to avoid confusion with the flag and to maintain data transparency. Done 5
One “0” is inserted after “1”, and “011111” is inserted.
010 ", the frame is decomposed after reception, restored to the original form of the data, and processed by the data terminal. In general, one continuous data is limited to a special use such as a flag or a failure notification signal described below. It does not appear in data during normal communication.

[0005] When the digital private line network 400 detects the occurrence of a failure in the digital private line network 400, it generates continuous data of "1" as a notification signal of the failure of the private line network and sends it to the PBX 411 on the receiving side. Further, when the data terminal 420 on the transmitting side is in a failure state, aborted or suspended, a signal having a continuous pattern of "1" is transmitted from the data terminal 420 to the digital private line network 400, and the digital private line network 400 To the receiving PBX 41
Transfer to 1.

When the PBX 411 on the receiving side detects the signal of the continuous pattern of "1" by the failure notification detecting circuit 451, it recognizes it as a failure in the data terminal 420 on the transmitting side or the digital private line network 400, and receives the signal after the fact. Performs a process determined when a failure such as invalidating data occurs.
The central monitoring and maintenance center detects this and automatically or manually performs backup processing such as failure recovery together with the transmitting PBX 410 or line switching from the digital private line network 400 to another public network such as an INS network. Perform

[0007]

As described above, conventionally,
Both the failure of the data terminal on the transmitting side and the failure of the digital leased line network are notified in the same continuous pattern of "1", and this is detected by the failure notification detecting circuit on the receiving side. And digital private line network failures could not be distinguished. Therefore, in order to ensure normal communication between both data terminals, if a failure notification signal is detected on the receiving side, even if the digital private line network is normal and only the transmitting data terminal has failed, it is automatically A backup process of manually or manually switching the transmission line to a public line network such as an INS network other than the digital leased line network has been performed.

For this reason, when the digital private line network is normal and only the data terminal on the transmitting side fails, it is not only impossible to ensure normal communication even after backup, but also
There is a problem that wasteful expenses such as usage fees for the public network are required, and that much time and man-hours are required to recover from the failure.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a digital leased line network capable of discriminating a fault location between a data terminal and a digital leased line network when a failure notification signal is received, thereby eliminating unnecessary backup and other operations. An object of the present invention is to provide a failure determination device and a determination method.

[0010]

SUMMARY OF THE INVENTION A fault judging device for a digital leased line network according to the present invention comprises: a fault notification detecting means for a data terminal for detecting a fault notification signal of a data terminal on a transmitting side; Terminal failure notification signal converting means for converting a signal into a predetermined terminal failure notification signal and sending the signal to the digital leased line network; terminal failure notification signal detection means for detecting a terminal failure notification signal received from the digital leased line network; And a failure location determining means for determining a failure location based on the terminal failure notification signal and the failure notification signal of the data terminal and the digital private line network.

In the data terminal failure notification signal transmitted by the data terminal and the failure notification signal transmitted by the digital leased line network, all consecutive bits have a logical value of 1, and the terminal failure notification signal converted on the transmission side is used. The signal preferably has at least one bit of a logical value 0 among consecutive bits of a predetermined length.

According to the digital private line network fault judging method of the present invention, a transmitting terminal detects a fault notification signal of a data terminal, converts this signal into a predetermined terminal fault notification signal, and sends it to the digital leased line network. When the terminal failure notification signal is detected on the reception side, it is determined that only the data terminal on the transmission side has failed, the failure notification signal is detected on the reception side, and the failure notification signal on the data terminal is transmitted on the transmission side. If it is detected, it is determined that both the data terminal on the transmitting side and the digital leased line network have failed.If the failure notification signal is detected on the receiving side and the failure notification signal on the data terminal is not detected on the transmitting side, It is determined that only the digital leased line network has a fault.

[0013]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a system configuration diagram of one embodiment of the present invention, FIG. 2 is a connection diagram of terminal failure detection circuits 160 and 161 for detecting a failure notification signal from a data terminal, and FIG. FIG.

As shown in FIG. 1, the data transmission system of this embodiment has data terminals 120 and 121 in which routers, frame relays, and the like alternately become a transmitting side and a receiving side, respectively.
Are connected via the respective terminal interfaces 150 and 151, and the two PBXs 110 and 111 of the time-division switch.
And a digital private line network 100 connected between the two PBXs 110 and 111 via digital trunks 130 and 131, and a data terminal 10 via the CPU 181.
The central monitoring and maintenance center 180 monitors the communication state between the communication terminals 2 and 121 and controls line switching and the like.

The fault notification signal of the data terminal and the fault notification signal of the digital leased line network are both signals in which consecutive bits have a logical value "1" as in the prior art. If the device is set so as to include one or more logical values "0" so that it can be distinguished from the failure notification signal, the present invention can be easily realized by modifying a conventional device.

As shown in FIG. 2, each of the terminal interfaces 150 and 151 of the PBXs 110 and 111 is provided with a terminal failure detection circuit for detecting a continuous pattern of "1" of a data terminal failure notification signal transmitted from the data terminals 120 and 121. 160 and 161. Digital trunk 130,
Reference numeral 131 denotes an interface of the PBXs 110 and 111 with respect to the digital private line network 100. The interface 131 includes failure notification detection circuits 140 and 141 on the input side from the network and terminal failure notification switching circuits 170 and 171 on the output side from the private line network.

The terminal failure notification switching circuits 170 and 171 on the output side for the leased line network are provided by the central monitoring and maintenance center 180.
Is transmitted to the digital private line network 100 according to the instruction of "
1 "The failure notification signal of the data terminal of the continuous pattern is
It switches to a terminal failure notification signal of a predetermined pattern including "0". On the other hand, the failure notification detection circuit 140 on the input side from the network,
141, as in the prior art, all the consecutive bits which are the failure notification signals of the data terminal and the digital private line network are all "".
When a signal consisting of "1" is transmitted, this is detected, and when a terminal failure notification signal in which at least one of the consecutive bits of a predetermined length has a logical value of 0 is transmitted, this is also detected. Can be detected.

Next, a description will be given of the operation of the apparatus and a method of determining a fault location with reference to FIG.

(A) When a failure occurs in the line from the PBX 110 on the transmitting side to the PBX 111 on the receiving side in the digital private line network 100, each bit is transmitted from the digital private line network 100 to the PBX 111 as a failure notification.
A continuous signal of "1" is transmitted, and the PBX 111 on the receiving side detects this by the failure notification detecting circuit 141. The central monitoring and maintenance center 180 transmits the terminal failure detecting circuit 16 on the transmitting side.
0 is checked, and since a failure has not been detected in the data terminal 120, the location of the failure is identified by the digital private line network 10.
Judge as 0.

(B) In the case of a failure of the transmitting terminal 120 accommodated in the PBX 110, a continuous signal of “1” issued from the terminal 120 is transmitted to the digital leased line network 100 as a failure notification signal. At the same time, it is detected by the terminal failure detection circuit 160 of the terminal interface 150. "1" transmitted to the digital private line network 100
The failure notification signal of the continuous signal is detected by the failure notification detection circuit 141 on the receiving side. The detection of the transmitting side and the detection of the receiving side are respectively notified to the central monitoring and maintenance center 180 which monitors these devices. Based on the notification from the two, the central monitoring and maintenance center 180 instructs the terminal failure notification switching circuit 170 on the transmission side to switch the failure notification signal to a predetermined terminal failure notification signal and transmit it to the digital leased line network 100. The digital leased line network 100 once sends a fault notification signal of one continuous signal to the receiving side in response to the fault notification signal from the data terminal 120 received first, but after the fault notification signal is switched, The signal after this switching is transmitted to the receiving side as it is. Accordingly, the failure notification detection circuit 141 on the receiving side first detects the failure notification signal of one continuous signal, and then detects the switched failure notification signal. The central monitoring and maintenance center 180 determines that the failure occurrence location is not in the leased line network but is in the data terminal on the transmission side because the failure notification detection circuit 141 on the receiving side has detected the switched failure notification signal. . In this case,
Since the terminal failure detection circuit 160 naturally detects the failure notification signal, it does not need to be checked again, but it may be checked to check for a malfunction of the circuit.

(C) Next, assuming that both the data terminal and the leased line network have failed almost simultaneously, first, a continuous signal of 1 is sent from the digital leased line network 100 to the receiving side as a failure notification signal of the leased line network. Sent out. Thereafter, the digital leased line network 100 receives the failure notification signal of the data terminal and its switching signal from the transmitting side.
00 during the digital private line network 100
One continuous signal as its own failure notification signal is continuously transmitted as it is. If the data terminal failure occurs early,
If the switching signal has been transmitted to the receiving side, the switching signal is again transmitted to the receiving side as one continuous failure notification signal of the digital leased line network 100. In the central monitoring and maintenance center 180, the failure notification detection circuit 141 on the receiving side detects the failure notification signal of one continuous signal and the terminal failure detection circuit 16 on the transmission side.
Since 0 detects the failure notification signal, it is determined that a double failure has occurred in both the data terminal 120 and the digital private network 100.

In the event that both are faulty, the central monitoring and maintenance center 180 continues monitoring and the fault notification detection circuit 14
When 1 detects the switched terminal failure notification signal,
It can be determined that one of the double failures has recovered from the failure of the digital leased line network 100.

As described above, according to the present embodiment, the location where a failure has occurred can be clearly distinguished between a data terminal and a digital private line network. It is effective for recovery and efficient use of data communication.

[0025]

FIG. 2 is a block diagram showing one example of a failure notification detecting means of a data terminal.
In the circuit of the embodiment, the data bits transmitted from the data terminal 120 and the synchronization clock corresponding to the data transmission speed from the PBX 110 are input to synchronize the continuous number of logical values 1 of the data bits transmitted from the data terminal. When it is detected that the failure notification signal of the data terminal has been detected for more than a predetermined time by counting with the pulse of the clock,
The central monitoring and maintenance center is notified via the PU 181.
The synchronous clock may change because it needs to correspond not only to the transmission speed of the digital leased line network but also to the transmission speed of the INS network where the transmission line is switched.

[0026]

As described above, according to the present invention, a failure notification signal of a data terminal is detected on the transmitting side, this failure notification signal is switched to a predetermined terminal failure notification signal and transmitted to the digital leased line network, and a failure is detected. By detecting the notification signal, the data terminal, and the failure notification signal signal of the digital leased line network, it is possible to determine the location of the failure separately for the data terminal and the digital leased line network. There is an effect that failure recovery can be performed quickly and effectively, such as by eliminating useless backup by the INS network, and the efficiency of data communication can be increased.

[Brief description of the drawings]

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

FIG. 2 is a connection diagram of terminal failure detection circuits 160 and 161.

FIG. 3 is an explanatory diagram of fault occurrence location determination in the embodiment of FIG. 1;

FIG. 4 is a system configuration diagram of a conventional example.

FIG. 5 is an explanatory diagram of occurrence and detection of a failure in the embodiment of FIG. 4;

[Explanation of symbols]

100, 400 Digital leased line network 110, 111, 410, 411 PBX 120, 420, 421 Data terminal 130, 131, 440, 441 Digital trunk 141, 450 Failure notification detection circuit 150, 430, 431 Terminal interface 160, 161 Terminal failure Detection circuit 170, 171 Terminal failure notification switching circuit 180, 480 Central monitoring and maintenance center 181 CPU

Claims (4)

(57) [Claims] An exclusive digital terminal for detecting a failure by detecting a failure notification signal of a data terminal on a transmitting side and a digital private line network transmitted via a digital private line network connected to a line switching device on a receiving side to determine the occurrence of a failure. A fault determining device for a line network, a fault notification detecting means of the data terminal for detecting a fault notification signal of the data terminal on a transmitting side, and switching the detected fault notification signal of the data terminal to a predetermined terminal fault notification signal, Terminal failure notification signal switching means for transmitting to the leased line network; terminal failure notification signal detection means for detecting a terminal failure notification signal received from the digital leased line network; the detected terminal failure notification signal; A digital-to-digital converter characterized by having a fault location judging means for judging a fault occurrence location based on a fault notification signal of a line network. Failure determination device of the line network. 2. A fault notification signal for a data terminal and a fault notification signal for a digital leased line network all have consecutive logical bits of 1, and the terminal fault notification signal is a continuous faulty bit of a predetermined length. 2. The apparatus according to claim 1, wherein at least one bit is set to a logical value of zero. 3. The failure notification detecting means of the data terminal,
A data bit sent from the data terminal and a synchronous clock for data transmission of the digital leased line network are input, and it is detected that the logical value 1 of the data bit sent from the data terminal has continued for a predetermined time or more. 3. The fault judging device for a digital private line network according to claim 1, wherein a detection signal of a fault notification signal of the data terminal is output. 4. A data terminal failure notification signal from a data terminal on the transmission side is transmitted to a digital leased line network, and the digital leased line network receives the data terminal failure notification signal or the digital leased line network failure. Sending a notification signal to a receiving side, detecting at the receiving side each of the fault notification signals sent to the receiving side, and determining a fault in the digital private line network. The transmission side detects the transmitted data terminal failure notification signal, and when the data terminal failure notification signal is detected on the transmission side, switches the failure notification signal to a predetermined terminal failure notification signal and performs digital switching. The terminal transmits the switched terminal failure notification signal to the leased line network, the reception side detects the switched terminal failure notification signal, and the transmission side transmits the data terminal failure notification signal. When a signal is detected, it is determined that a failure has occurred in the data terminal on the transmission side, a failure notification signal for the digital private line network has been detected on the reception side, and a failure notification signal for the data terminal has been detected on the transmission side. When it is determined that a failure has occurred in both the data terminal on the transmission side and the digital leased line network, a failure notification signal for the digital leased line network is detected on the reception side, and the failure of the data terminal is detected on the transmission side. If no failure notification signal is detected, it is determined that a failure has occurred in the digital leased line network.