JPS63102520A - Network supervisory equipment - Google Patents

Abstract

PURPOSE:To simply decide a faulty location by constituting a terminal station address by its tree branch stage and a branch number in a tree form network, sending a response signal from a terminal station corresponding to the address and allowing a central station to detect a response signal not arrived yet thereby discriminating a faulty stage and branch location. CONSTITUTION:A synchronizing signal sent from a synchronizing signal transmission circuit 11 of the central station 1 is received simultaneously by each terminal station. A response signal is sent from a response signal generating circuit 22 of each terminal station in response to an output of a delay circuit 21 while being retarded bythe delay circuit 21 by time corresponding to a terminal station address of tree form. In this case, the address of each terminal station depends on an i-th stage in a branch stage number M of a branch point set by the initial design of the network and the branch number (n) at a multi-branch stage and differs in each terminal station. The response signal from the terminal station is received by the central station 1, and timing not receiving the response signal is detected by a fault branch detection circuit 12 and a fault branch interval is detected based on the discriminated terminal station address number.

Description

[Detailed Description of the Invention] [Summary] This application solves the complexity of logic for detecting abnormalities in branch sections in a tree-shaped network.
The terminal station address is composed of the branch stage and branch number of the tree, the terminal station sends a response signal corresponding to that address, the central station detects the unarrived response signal, and detects the abnormal branch stage and branch section. This invention discloses a network monitoring device that determines the

[Industrial application field]

The present invention relates to network monitoring 'AKI', particularly
The present invention relates to an optical network monitoring device that connects a central station and terminal stations with optical signals and monitors branch sections along the way.

Even if an abnormality such as a disconnection occurs in an optical cable, it cannot be determined from its appearance, so a method is required for the system to detect the occurrence of any abnormality.

In particular, in tree-shaped fiber optic networks, which are expected to distribute information to each home in the near future, abnormalities in the network can be quickly detected and maintenance personnel can be dispatched to prevent service degradation. It is necessary to dispatch personnel to the abnormal location.

[Conventional technology]

FIG. 10 is a schematic diagram showing a conventional tree-type network monitoring system, in which a central station 1 and terminal stations A, B, and C are connected via optical fibers 50-1, 50-2 and branch points 51, 52. There is. These terminal stations have a series of numbers (001), (002) unrelated to the branch section from each branch point.
, (003) are given.

An optical supervisory signal is sent from the central station 1 to the terminal stations A to C, and the optical supervisory signals are simultaneously received at the terminal stations A to C. If the address included in the optical monitoring signal is addressed to the terminal station, the terminal station sends a return signal including the address of the terminal station to the central station 1.

The central station 1 has a "branch section signal determination table" as shown in FIG. 11, and refers to this table to determine an abnormal branch section based on return signals from each terminal station.

In other words, in the example of Fig. 11, if all terminal stations are assumed to be normal, ■ An abnormality in the section from the center station l to the branch point 51 occurs when there is no return signal from any terminal station (signal interruption is indicated by ×). ), ■ An abnormality in the section from branch point 51 to 52 is when there is a return signal from only terminal station C, ■ An error in the section from branch point 52 to terminal station A is when only the return signal from terminal station A is present. ■When there was no abnormality in the section from branch point 52 to terminal station B, only the return signal from terminal station B was absent.
Then, ■ An abnormality in the section from branch point 51 to terminal station C indicates when there is only a return signal from terminal station C, and this table is memorized and the abnormal section is determined based on this. Ta.

[Problem that the invention seeks to solve]

In this way, in conventional network monitoring devices,
Since the monitoring signal sent from the central station was simply looped back at the terminal station, (1) both the central station and the terminal stations had to transmit a signal including the address, but the central station was unable to handle the number of terminal stations. (2) At the central station, the transmission must be repeated for
(3) When adding terminal stations, it takes a lot of time and effort to maintain and modify the "branch section signal determination table."

Therefore, an object of the present invention is to realize a network monitoring device that can easily determine an abnormal section without using complicated address information and tables.

[Means for solving problems]

FIG. 1 is a diagram conceptually showing a tree-shaped network monitoring device of the present invention for solving the above problems, in which 1 is a central station, and 2 is a terminal station connected to a branch of a plurality of branch stages. The terminal station 2 includes a delay circuit 21 that delays a constant periodic synchronization signal from the central station 1 by a time corresponding to the branch stage and the terminal station address associated with the branch number of the branch stage; The central station 1 includes a response signal generation circuit 22 that transmits a response signal in response to the output, and a synchronization signal transmission circuit 11 that transmits a synchronization signal, and a terminal station address that determines the terminal station address from the timing when the response signal does not arrive. and an abnormal branch detection circuit 12 that detects an abnormal branch that occurs.

[For production]

In FIG. 1 showing the present invention, a synchronization signal transmitted from a synchronization signal sending circuit 11 of a central station 1 is simultaneously received by each terminal station. Each terminal station is delayed by a delay circuit 21 for a time corresponding to the terminal station address associated with the branch stage and branch number of the tree-shaped optical network, and in response to the output of this delay circuit 21, a response signal is sent to a response signal generation circuit. 22.

In this case, as shown in Fig. 2, the address of each terminal station (marked with ○゛) is the address of the first stage in the number of branching stages M of the branching point (marked with .) set in the initial design of the network, and the address of each branching stage. with branch number n in H,×lQfM−1+ + n
, ×lQfM-21+-+n, x10+'1-i)+・
+n, fil (however, 1615
M, O≦n≦9). Therefore, the delay time in the delay circuit 21 is also determined by this address and differs for each terminal station.

The response signal from the terminal station is received at the central station l,
The abnormal branch detection circuit 12 detects the timing at which the response signal does not arrive, and the terminal station address number is determined based on the detected timing. An abnormal branch section is detected based on the determined terminal station address number.

〔Example〕

The present invention will be explained in detail below.

FIG. 3 is a diagram showing an embodiment of the network monitoring device according to the present invention shown in FIG. A response signal receiving circuit 31 that receives a response signal from a terminal station, an address table 32 having addresses according to the timing of the optical synchronization signal, and a synchronization sending circuit 11
a comparison circuit 33 which receives a start signal from the terminal station and compares it with the address table 32 to detect the address of the synchronization signal for which no response signal is received from the terminal station; and a determination circuit 34 that determines the branch number of , as an abnormal branch.

Further, the terminal station 2 includes a terminal device 23, and a series body of a delay circuit 21 and a response signal generation circuit 22 shown in FIG. 1 is connected to both ends of the terminal device 23. Furthermore, the delay circuit 21 includes a separation circuit 21a that separates the downlink data from the central station 1 and the synchronization signal, and a delay element 21b, and the response signal generation circuit 22 includes a pulse generation circuit 22a that responds to the output of the delay element 21b. and a synthesizer 22b that synthesizes the response signal and the upstream data of the terminal device 23 and sends it out.

Next, the operation of the embodiment shown in FIG. 3 will be explained with reference to the network configuration example shown in FIG. 4 and the synchronization signal transmission quimchard example shown in FIG. 5.

In FIG. 3, A to G indicate the terminal stations collectively referred to as terminal station 2 in FIG. . That is, in (1), for example, the terminal station F has the number of branching stages M
=4, each number of branches n1=0,! 'lz =n3 =n4=
1, so its address is 0+100+10↓1
(0111).

A synchronization signal sending circuit 11 of the central station 1 sends a synchronization signal of a constant period to all terminal stations A to F.

Each terminal station receives the synchronization signal, separates the synchronization signal from the transmission data in a separation circuit 21a, and sends it to the delay element 21b.

This delay element 21b has a delay time specific to each terminal station, and this delay time is determined in relation to the address number of each terminal station. Therefore, as shown in FIG. 6, the delay time 1 from receiving the synchronizing signal to generating the pulse response signal in the pulse generating circuit 22a is 1 in the example shown in FIG.
．． -1. There will be up to Note that this response signal may be, for example, a simple pulse without information.

This response signal is combined with transmission data by a combiner 22b and sent to the central station l.

At the central station l, a response signal receiving circuit 31 receives the response signal. In this case, the response signals are sent at different times at each terminal station, so they are never received at the same time (transmission delays are not considered since they are optical signals).

The comparison circuit 33 compares the response signal from the circuit 31 with the address timing table 32 to detect a terminal station address from which no response signal is received.

That is, when the second branch of the second branch stage exhibits an abnormal state as shown in Fig. 4, the response signal that should arrive from the terminal station D-G is not received as shown in Figs. 5 and 7. It turns out. Therefore, in the comparator circuit 33, the 8th
According to the flowchart of the program shown in the figure, the timing data is extracted from the address timing table 32 in step S1), the check is made to see if a response signal has been registered or not (step S2), and the check is made to see if a response signal is received in step S3). Address number of the terminal station (OIOX), (0110), (0111)
, (012X) (X is undefined) is passed to the determination circuit 34 (step S4).

The determination circuit 34 detects an abnormal branch according to the flowchart of the program shown in FIG. 9 that is stored internally.

. That is, common numbers are searched in order from the first branch stage indicated by the first number of the terminal station address from the comparison circuit 33 (
Step 5IO1Sll), and when there is no common number, the abnormal branch stage and branch number are determined based on how many stages there are common numbers and what the common numbers are (step 512).

In the example shown in FIG. 4, the terminal station addresses of the response signal received by the central station 1 are the addresses (0000) and (0000) of the terminal stations A to C.
001) and (OOIX), and the addresses of the terminal stations DG that could not receive it are as follows.

Therefore, it can be seen that 111 is common up to the second branching stage. As a result, it is determined that "branch number 1 of the second branch stage is an abnormal branch."

〔Effect of the invention〕

As described above, according to the network monitoring device according to the present invention, each terminal station returns to the central station a response signal obtained by delaying the synchronization signal from the central station by the time corresponding to the terminal station address, and at that time, Abnormal branching is determined by detecting the terminal station address from which no response signal is returned using the timing table, so the central station table only needs to have the terminal station address, which greatly reduces maintenance when adding terminal stations. This has the effect that it is easier to use, and the synchronization signal only needs to be transmitted once.

[Brief explanation of the drawing]

FIG. 1 is a block diagram conceptually showing a network monitoring device according to the present invention, FIG. 2 is a diagram showing the arrangement of addresses of terminal stations in a tree structure for detailed explanation of the present invention, and FIG. 3 is a block diagram of the present invention. 40 is a block diagram showing an example of a network monitoring device according to the invention; FIG. 40 is a diagram showing an example of a network configuration; FIG. 5 is a time chart showing transmission of a response signal from a terminal station; FIG. 6 is a synchronization signal Figure 7 is a diagram showing the timing waveform of the address timing table, Figure 8 is a flowchart of the program executed by the comparator circuit, and Figure 9 is a flowchart of the program executed by the determination circuit. 10 is a network configuration diagram for explaining a conventional network monitoring method, and FIG. 11 is a diagram showing a branch section signal determination table used in the method of FIG. 1 and 3, 1 is a central station, 2 is a terminal station, 11 is a synchronization signal sending circuit, 12 is an abnormal branch detection circuit, 21 is a delay circuit, 22 is a response signal generation circuit, and 31 is a response signal reception circuit. 32 is an address table, 33 is a comparison circuit, and 34 is a determination circuit. In the drawings, the same reference numerals indicate the same or corresponding parts. Special work applicant Fujitsu Co., Ltd. Agent Patent Attorney
Mori 1) Hiroshi (1 other person) 2-1, ;; The principle of the network monitoring device of this investigation Figure 1.
Figure 3: 1st stage 2nd stage 3rd stage 4th stage Example of 4R construction of a network according to an embodiment of the present invention Figure 6. Time chart showing the timing of the address table. Program flow chart for the comparison circuit. Figure 8. Program flow chart for the window circuit. Figure 9.

Claims (2)

[Claims] (1) A monitoring device for a tree-shaped network composed of a central station (1) and terminal stations (2) connected to branches of a plurality of branching stages, in which the terminal station (2) is connected to the central station ( a delay circuit (21) that delays a constant period synchronization signal from 1) by a time corresponding to the branch stage and the terminal station address associated with the branch number of the branch stage; and a delay circuit (21) that responds to the output of the delay circuit (21). and a response signal generation circuit (22) for transmitting a response signal, and the central station (1) includes a synchronization signal transmission circuit (11) for transmitting the synchronization signal, and a synchronization signal generation circuit (11) for transmitting the synchronization signal; A network monitoring device comprising: an abnormal branch detection circuit (12) that generates a terminal station address and detects an abnormal branch. (2) The abnormal branch detection circuit (12) communicates with the response signal receiving circuit (31), an address table (32) having addresses according to the timing of the synchronization signal, and based on the address table (32). A comparison circuit (33) that generates an address number for which no response signal is received; and a determination circuit (33) that determines a branch number at the previous stage of a branch stage that does not match among the address numbers output from the comparison circuit (33) as an abnormal branch. 34) A network monitoring device according to claim 1, comprising: