JPH03181237A - Diagnostic method for multiplex device - Google Patents

Abstract

PURPOSE:To shorten the time required for recovery of a fault by controlling a changeover switch for each time slot based on the value of a diagnostic time slot table and at the time sending a specific diagnostic pattern via the time slot. CONSTITUTION:A changeover switch 102 is operated via a diagnostic time slot table 101 based on the time slot value of a circuit 3 which is counted by a time slot counter 105 at the side of a device 1. Then the diagnostic data received from a diagnostic pattern generating part 103 is sent to the circuit 3. At the side of a device 2, a changeover switch 202 is operated via a time slot counter 205 and a diagnostic time slot table 201. Then the received data is returned. The device 1 operates a changeover switch 106 via the functions of the counter 105 and the table 101. Thus the device 1 sends the received data to a diagnostic pattern check part 109 to collate it with a transmission diagnostic pattern.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to high-speed digital lines and comprehensive digital networks (
The present invention relates to an automatic diagnosis method for a time division multiplexer connected to an ISDN (ISDN), and particularly to a method for diagnosing a multiplexer that can isolate and analyze failures depending on time slots.

[Prior Art] Conventional methods for maintenance and diagnosis of digital transmission equipment are as described on pages 186 to 188 of "Transmission Facility Design for Digital Networks" (published by the Telecommunications Association of Japan in 1980). In addition to monitoring the network side due to frame synchronization loss, clock disturbance, alarm signals, etc.
A repeat test may be conducted to isolate the fault location.

FIG. 7 is a conceptual explanatory diagram of a loopback test of a conventional digital transmission device. As shown in Figure 4, in the loopback test, a data loopback mechanism is installed at several points in the equipment between the terminals, a diagnostic pattern is transmitted from a certain point on the transmission path, and the received data is returned. By comparing and checking the pattern with the transmission pattern, the normality of the transmission path is checked. For example, in this example, if the return at return point ■ is normal and an abnormality is detected at return at ■, there is a high possibility that there is a failure in the line or line interface between return point ■ and It becomes possible to separate the Recently, this return diagnosis function has been automated,
A device is known that automatically generates a diagnostic pattern, sets a return point, and collates and checks a received pattern by inputting a command from a network management device.

FIG. 8 is a block diagram of a loopback diagnostic function illustrating a conventional multiplexing device diagnostic method. A conventional foldback test method will be explained.

Main control unit 100 of line interface unit 10 in device 1
receives a command from the network management terminal 4, and sets a changeover switch by the command register 111 so that between the diagnostic data from the diagnostic pattern generation section 103 and the online data from the multiplexing section 150, the diagnostic data is placed on the line. 102
Switch. Data output from this changeover switch 102 to the line 3 via the transmission buffer 107 is input to the opposing device 2. The device 2 also receives commands from the network management terminal 4,
The main control unit 200 sets the changeover switch 202 using the command register 211 so that the received data is sent back instead of the multiplexed data as the transmission data. Device 1
The diagnostic data input back to the diagnostic pattern check section 10 passes through the reception buffer 108 and the changeover switch 106.
9 and is compared with the transmission pattern, and if they do not match, it is determined that there is some kind of failure in the return route, that is, on the devices 1 and 2 or the line 3.

[Problems to be Solved by the Invention] In the above-mentioned conventional technology, since it is possible to determine whether the return route is normal or abnormal, it is possible to identify that the fault location is within the return route of the entire network.

Because information beyond the fact that there is an abnormality cannot be returned, it usually takes a lot of time to isolate the problem by repeating the test, and then to actually identify the faulty part and repair it by replacing it. In particular, if there is a line within the suspected return route as described above, you will have no choice but to take steps such as requesting an investigation from the line carrier, changing the configuration of your own device based on the results, and then retesting. It took a considerable amount of time to fully recover. For example, a mode in which a failure appears only in a specific time slot (group) on the network (line) side may occur depending on the structure of the equipment on the line carrier side. In this case, if there is no obvious abnormality such as violation of the coding rules, it is unlikely to be a fault on the line side using simple methods such as looking at the digital data waveform on the line, so use another time slot to isolate the problem. It took a considerable amount of time because we had to think about changing the settings of the opposing device and repeating the test again. In addition, the method of diagnosing a specific time slot on a single device cannot diagnose the line interface section of the device, and is therefore not sufficient for distinguishing between the line and the device. Furthermore, especially when connecting a multiplexer to an 15DN network, there is a mode in which data is passing correctly within the time slot as a failure mode for a specific time slot, but when you try to connect the time slots and send data, it does not pass. Conceivable. This mode will now be explained with reference to FIG.

FIG. 9 is a diagram showing the structure of a frame on a 1.5 Mbps digital transmission line. This one frame is repeated at 8kHz. A unit of 8 bits (64 kbps) is called one time slot, and one frame consists of 24 time slots and 1 bit for synchronization (framing bit), a total of 193 bits. In the 15DN network, exchange is performed in units of time slots, so it is possible to take a different route for each time slot, so the frame phase relationship between time slots is T S S I (Time S lo
t5equence integrity) is not guaranteed. Therefore, sending and receiving data across time slots is basically not allowed.
, Hl are specified in the calling sequence, then the network guarantees this TSSI for 6 time slots for H and 24 time slots for H1.

Therefore, by specifying this service, it becomes possible to transmit data strings of 64 kbps or more via the 15DN network, but in the unlikely event that a TSSI error occurs in the network that includes this line, it will not be a so-called fixed failure. Since the data itself is still being passed through, it is expected that it will be even more difficult to isolate the problem. On the other hand, in the case of the 15DN network, if it is determined that a particular time slot (group) is bad, it is possible to take measures such as avoiding that time slot and re-calling, and the effect of being able to isolate the time slot abnormality is As mentioned above, abnormalities such as data not passing only in a specific time slot (group) or TSSI not being observed cannot be sufficiently isolated using conventional loopback diagnosis methods, and it is difficult to recover the network. The problem was that it took a long time.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for diagnosing a multiplexing device that can isolate and analyze failures including time slot-dependent TSSI abnormalities.

[Means for Solving the Problems] In order to achieve the above object, a multiplexing device diagnostic method according to the present invention includes a time slot counter as a means for counting time slots on a line in a return diagnostic circuit, and a time slot counter as a means for counting time slots on a line. It has a diagnostic time slot table that can be set from the main controller so that diagnosis can be performed by specifying any time slot (group) based on the value of the time slot counter. The diagnostic pattern generation unit is configured to be able to control each time slot based on the values in the slot table, and to send out a unique diagnostic pattern depending on the time slot.

[Operations] The diagnosis method for the multiplexing device described above is based on the configuration of the loopback diagnostic circuit as described above. A faulty time slot can be identified by performing a loopback test for each slot or by changing the combination of time slots. In addition, when transmitting diagnostic patterns for multiple time slots simultaneously, it is possible to set separate diagnostic patterns depending on the time slots, so even if there is a frame phase shift (TSSI abnormality) in a specific time slot in the received data, it can be detected. It becomes possible.

Furthermore, since the diagnosis range can be specified to some time slots instead of all time slots, it is possible to diagnose only the suspect time slot without affecting time slots in which transmission and reception are normally performed. Furthermore, since it is possible to reconstruct frames while avoiding time slots that have been diagnosed as timeslot abnormalities, it is possible to minimize the reduction in transmission capacity of the system even when a time slot abnormality occurs on the line and until recovery. becomes possible.

[Example] Examples of the present invention will be described below with reference to FIGS. 1 to 6.

FIG. 1 is a block diagram of a return diagnosis function showing an embodiment of the diagnosis method for a multiplexing device according to the present invention. In FIG. 1, 1 and 2 are multiplexing devices, 3 is a line, 4 is a network management terminal, IO is a line interface section, 100.200 is a main control section, 101.201 is a diagnostic time slot table,
102.106.202 is a changeover switch, 103 is a diagnostic pattern generation unit, 105.205 is a time slot counter, and 107.207 is a transmission buffer.

108, 208 are reception buffers, 109 is a diagnostic pattern check section, 120.220 is a separation section, 130.23
0 is a terminal interface section, 140 and 240 are frame configuration control sections, and 150 and 250 are multiplexing sections.

FIG. 1 shows a block structure schematically representing the return diagnosis function for facing multiplexing devices. Multiplexing device 1 and multiplexing device 2 are connected via line 3, and the line interface on device 1 side Diagnostic pattern generation unit 103 of unit 10
This figure shows a case in which the diagnostic data generated in the vX2 side is returned and collated and checked by the diagnostic pattern check section 109 on the device 1 side. Both devices 1 and 2 are network management terminals 4
When the network management terminal 4 issues a return diagnostic command for a specific time slot, both devices i! l, 2
The main control unit 100.200 sets the diagnostic time slot table 101.20 so that the changeover switch 102.106.202 switches to the diagnostic side at the designated time slot.
Set 1.

As an example, a case will be described in which time slots 1 and 2.4 of a frame on a 1.5 Mbps digital transmission line shown in FIG. 9 are diagnosed. First, on the device 1 side, the 1-diagnosis time slot table 101 operates the changeover switch 102 based on the time slot value on the line 3 counted by the time slot counter 105 by updating the counter value by 1 every 8 bits from the framing bit. , in time slots 1, 2.4, the diagnostic data from the diagnostic pattern generation section 103 is selected, and in the other time slots, the online data from the multiplexing section 150 is selected and transmitted onto the line 3 via the transmission buffer 107. On the device 2 side, the changeover switch 202 is operated in the same manner using the time slot counter 205 and the diagnostic time slot table 201, and the data received in time slots 1, 2.4 is returned and transmitted as is, and the other time slots are normally transmitted. Send and receive online. In the device 1, the changeover switch 106 is operated by the functions of the time slot counter 105 and the diagnostic time slot table 101, and this time, of the data string received via the reception buffer 108, only the data of time slots 1, 2.4 are checked for the diagnostic pattern. The data is sent to the unit 209 and checked against the transmission diagnostic pattern.

Next, from Figure 2 (a) and (b), the TSSI of Figure 1 is calculated.
Explain how to detect anomalies. Figure 2 (a), (
b) is an explanatory diagram of an example of framing data for detecting the TSs defect in Fig. 1, and Fig. 2(a) is an illustration of the diagnostic pattern ABC.
DEF, FIG. 2(b) shows the reception pattern ABFDEC. As a result of the above, for example, it is possible to transmit and receive engineering data in each time slot, and the diagnostic pattern "ABCDEF" is repeatedly transmitted using time slots 1, 2.4 of frames 1, 2, and 3.4 as shown in FIG. Then, for example, if a mode failure occurs in which only time slot 4 arrives one frame later than other time slots on line 3, the diagnostic pattern check unit 10
The received data appears in the receiving buffer 108 of No. 9 as shown in FIG. 6(b). Looking at this reception pattern, time slot l of frames 1, 2, 3.4.

The data appearing in 2.4 are “AD” and “BE” respectively.
"CF" is correct, but if you look at it as a data string, 'A'
BFDEC", which is different from the transmission pattern in Figure 6(a), and therefore time slot 4 is
It can be seen that a TSSI abnormality has occurred in which the frame phases of the two frames are different.

According to this embodiment, TSS is transmitted between the multiplexers on both sides of the line.
Since problems that depend on time slots, including I abnormalities, can be identified without affecting normally operating time slots, the accuracy of fault isolation is significantly improved compared to conventional methods, and the time required for fault recovery is reduced. This can be significantly reduced.

Next, the details of the method of generating and checking the diagnostic pattern for detecting TSSI abnormality shown in FIG. 1 will be explained. FIG. 3 is a block diagram of a configuration example of the diagnostic pattern generation section 103 shown in FIG. 1. In Figure 3, 1031 is parallel/
A serial (P/S) conversion circuit, 104 is a transmission frame counter, and 105a is a transmission time slot counter. The 5-bit count value of the transmission time slot counter 105a and the lower 3 bits of the frame counter 104, which is updated by 1 every time a framing bit is transmitted (every 24 time slots), are combined to form the 8-bit diagnostic data shown in FIG. Generate D, -D. FIG. 4 is an explanatory diagram of an example of the diagnostic pattern shown in FIG. 3. This diagnostic data is P
The signal is transmitted via the /S conversion circuit 1031 under the control of the changeover switch 102.

FIG. 5 is a block diagram of an example of the configuration of the diagnostic pattern check section 109 shown in FIG. In FIG. 5, 105b
is the reception time slot counter, 1091 is the serial/
Parallel (S/P) conversion circuit, 1092 is time slot comparator (CMP), 1093 is data latch, l0
94 is a frame comparator (CMP).

To check the returned diagnostic pattern, among the received data, the data of the time slot under diagnosis is transferred to the S/P conversion circuit 1091 under the control of the changeover switch 106.
is input to the comparator 10 and converted to parallel data.
92, the lower five bits are compared with the value of the reception time slot counter 105b, and a data check is performed for each time slot. Furthermore, the upper 3 bits are latch 10
It is compared with the frame counter value of the first diagnostic time slot in the frame held by 93, and it is checked whether the same value is taken in the diagnostic time slot in the next frame. In the above, for example, if a certain time slot is determined to be normal in time slot comparison but abnormal in frame comparison, it can be determined that this has occurred in TSSISS in that time slot.

Note that the above configuration does not particularly require any elements such as a memory, and is realized by an IC with standard functions such as a counter, a latch, and a comparator, and is a configuration that can be realized at low cost and is suitable for LSI implementation.

FIG. 6 is a block diagram of a return diagnosis function showing another embodiment of the multiplexing device diagnosis method according to the present invention. In FIG. 6, the same reference numerals as in FIG. 1 indicate corresponding parts, and 110 is a failure time slot storage section. This configuration is obtained by adding a failure time slot storage section 110 to the configuration shown in FIG. 1, and this change will be explained next. When it is determined that there is an abnormality in a particular time slot using the method explained in FIG.
9 to the fault time slot storage unit 110.

Based on the information stored here, the frame configuration control unit 14
0, the frame configuration is re-edited so as not to use the suspected failure time slot, and the control of the multiplexer 150 and the demultiplexer 120 is changed. This information is also transmitted to the opposing device 2, and communication is performed between the opposing devices using only normal time slots.

According to this embodiment, if it is determined that the fault is on the line side, normally the line operator will be asked to investigate and repairs or replacements will be made as necessary to restore the data, but during this time the data will be stored on the backup line etc. Unless a detour is taken, all data communication will be disabled during this time, but with this configuration, when a time slot is abnormal, a minimum amount of data can be communicated until the line side returns to IB.

Next, still another embodiment of the multiplexing device diagnostic method according to the present invention will be described. The above diagnostic method focuses on time slots, and it may be difficult or impossible to detect failures in the common parts and terminal interface parts of devices 1 and 2 due to the relationship between the occurrence position and return position of the diagnostic pattern. be. Therefore, in the above embodiment, as an initial diagnosis, a conventional loopback test is performed end-to-end, and if the test is normal, the diagnosis is terminated. By adopting the diagnostic method of performing diagnosis for each time slot as in the above embodiment, it is possible to significantly improve the ability to analyze and respond to abnormalities without changing the time and accuracy of confirming normality. becomes.

[Effects of the Invention] According to the present invention, it is possible to detect the quality of the data transmission path between opposing devices across the line, including faults that cannot be isolated using conventional diagnostic methods such as TSSISS in the network. This is effective in improving system reliability, such as reducing failure recovery time.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the diagnosis method for a multiplexing device according to the present invention, FIGS. The figure is a side view of the configuration of the diagnostic pattern generation section in Figure 1, Figure 4 is an explanatory diagram of an example of the diagnostic pattern in Figure 3, and Figure 5 is a diagram showing the example of the diagnostic pattern in Figure 1.
FIG. 6 is a block diagram showing another embodiment of the diagnosis method for a multiplexing device according to the present invention. FIG. 7 is a conceptual diagram of a loopback test of a conventional transmission device. FIG. 8 is a block diagram illustrating a conventional multiplexing device diagnosis method, and FIG. 9 is a frame configuration diagram of a 1.5 Mbps digital transmission line. 1.2... Multiplexing device, 3... Line, 4... Network management terminal, 10. ... line interface section, 100.
200... Main control unit, 101.201... Diagnosis time slot table. 102, 166, 202... changeover switch, 103.
...Diagnostic pattern generation unit, 104...Frame counter, 105.205...Time slot counter, 1
07.207...Transmission buffer, 108.208.
...Reception buffer, 109...Diagnostic pattern check section, 110...Fault time slot storage section, 120,
220... Separation section, 130.230... Terminal interface section, 140.240... Frame configuration control section, 150.250... Multiplexing section.

Claims (1)

[Claims] 1. Automatically generate and send a diagnostic pattern, return this data at the opposing device, compare and check the returned received diagnostic pattern with the transmitted pattern, and automatically check the normality of the line and device. In a method for diagnosing a multiplexing device to be confirmed, both devices are equipped with a time slot counter that automatically counts in synchronization with the time slot, and the time slot counter automatically controls the execution/suspension of the diagnostic function for each time slot, A method for diagnosing a multiplexing device, characterized in that a diagnosis pattern can be changed depending on a time slot. 2. The method of diagnosing a multiplexing device according to claim 1, wherein a combination of a time slot counter value and a frame counter value is used as the diagnosis pattern. 3. A claim characterized in that the device is provided with means for storing failure conditions for each time slot, and when an abnormality in a particular time slot is detected through the above diagnosis, it is possible to configure a frame by avoiding that time slot. Item 1. A method for diagnosing a multiplexing device according to item 1. 4. Claim 1 characterized in that, as the fault isolation means, first a return test is carried out for all time slots, and when an abnormality is detected in this test, a diagnosis is carried out for each time slot as a second test. A method of diagnosing the described multiplexing device.