JP2503947B2 - Communication network maintenance system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a maintenance system for a communication network in which a plurality of terminals share one transmission line for communication, and in particular, a terminal using a transmission line can be efficiently used. The present invention relates to a communication network maintenance system suitable for identification.

[0002]

2. Description of the Related Art A bus type communication network for performing N: N communication, a distribution type communication network for performing a 1: N communication, etc.
2. Description of the Related Art A communication network is known in which a plurality of terminals share one transmission path and communication is performed between the terminals. In such a communication network, for example, in the packet switching system,
Each terminal is given the right to transmit only during a predetermined time zone (time slot), and communicates using the transmission path at each time. However, since each terminal transmits information by a transmission signal, if a certain terminal sends out the transmission signal for a certain time or longer due to some failure or the like, the transmission path will be occupied and the communication of other terminals will be hindered. I will be lost. Conventionally, such a communication network is provided with a network management terminal, and when such a problem occurs, the network management terminal identifies the address information of the terminal included in the transmission signal to transmit the information. The terminal occupying the road can be located, and quick measures can be taken.

However, in general, a transmission signal transmitted from a faulty terminal has a random pattern or a continuous signal, so that the network management terminal cannot locate the corresponding terminal. Further, when the address information is not included, only the terminal itself can recognize such a state, and the network management terminal cannot locate the terminal. Regarding the maintenance of the communication network for the purpose of maintaining the performance of such a communication network, for example, refer to pages 247 to 247 of “New Data Transmission System” edited by Toshio Soejima (published by Sangyo Tosho Co., Ltd.). There are devices and techniques described on page 265.

[0004]

The problem to be solved is that, in the prior art, the network management terminal cannot correctly locate the terminal occupying the transmission path.
An object of the present invention is to solve these problems of the prior art, to easily locate a terminal that occupies a transmission path for a long time, to quickly eliminate the cause of failure, and to improve the performance of a communication network. It is to provide a maintenance system for the communication network.

[0005]

In order to achieve the above object, the communication network maintenance system of the present invention (1) occupies one shared transmission path at an arbitrary time, and uses a transmission signal. A plurality of terminals that transmit information, and a network management terminal that detects that any one of the plurality of terminals has occupied a transmission path for more than a predetermined time and detects the occurrence of a failure in the transmission path In the maintenance system of the communication network consisting of, each of the plurality of terminals includes an identification signal superimposing unit that superimposes an identification signal having a frequency component unique to each terminal on the transmission signal to be transmitted to the transmission path. The network management terminal sends out information to the transmission line by the transmission signal on which the identification signal is superimposed by the identification signal superimposing unit, and the network management terminal extracts the identification signal from the transmission signal received through the transmission line, and the identification signal extracting unit. Identification signal extraction In based on the extracted identification signal,
A terminal identifying unit that identifies a terminal corresponding to the identification signal, and when any one of the plurality of terminals detects an excess of the occupied time of the transmission path, the terminal that has exceeded the occupied time of the transmission path is located. It is characterized by

[0006]

In the present invention, each terminal superimposes an identification signal having a frequency component peculiar to each terminal on the transmission signal and sends it, and the network management terminal responds to each terminal from this transmission signal. By extracting the identification signal that
Locate each terminal. In this way, it becomes possible to easily and quickly locate the failed specific terminal, and the performance of the communication network maintenance system is improved.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a configuration relating to the present invention of a communication network maintenance system to which the present invention is applied. In FIG. 1, 1 and 2 are terminals for transmitting information by transmission signals, 3 is a transmission line shared by these terminals 1 and 2, and 4 is a transmission processing state of the terminals 1 and 2. It is a network management terminal that is used for monitoring and maintenance of the communication network. Conventionally used media for the transmission line 3 include a pair wire, a coaxial cable, an optical fiber, and a radio wave. The present invention
It is not specific to these transmission media and can be applied to any. For example, it can be applied to either a metallic cable or a communication network formed by using an optical fiber. Further, the topology of the communication network may be any of bus, loop, tree and the like. The terminals 1 and 2 are terminal transmission / reception circuits (denoted by TC in the figure) 5 and 6 for controlling transmission / reception of transmission signals to / from the transmission path 3, and terminals 1 and 2 respectively.
The main body of the terminal that performs the original processing operation as
7), and each of the terminal transmission / reception circuits 5 and 6 of the terminals 1 and 2 controls the transmission of a transmission signal to the transmission path 3 (described as TX in the figure) 9, 1
0, receiving circuits (described as RX in the figure) 11 and 12 for controlling the reception of the transmission signal from the transmission path 3, the terminal body 7,
A terminal interface (T in the figure) for controlling connection with
It is described as IF) 13 and 14. Further, the network management terminal 4 includes a network management terminal transmission / reception circuit 15 (BTC in the figure) for controlling transmission / reception of transmission signals to / from the transmission line 3.
, And a network management terminal body (described as BTE in the figure) for performing processing operations related to maintenance and the like as a network management terminal 1
And a network management terminal transmitting / receiving circuit 15
Is a transmission circuit (denoted by TX in the figure) 17 for controlling transmission of a transmission signal to the transmission line 3 and a reception circuit (denoted by RXM in the figure) for controlling reception of a transmission signal from the transmission line 3 1
8 and a terminal interface (described as TIF in the figure) 19 for controlling connection with the network management terminal body 16. Also, the terminals 1 and 2 and the network management terminal 4
In each of the above, 20 to 22 are output ports connected to the transmission line 3, and 23 to 25 are input ports connected to the transmission line 3. With such a configuration, in the communication network of this embodiment, the network management terminal 4 easily locates the terminals 1 and 2 that occupy the transmission path 3 for a long time. That is, each of the terminals 1 and 2 has a transmission signal used for transmitting information,
An identification signal having a frequency component unique to each terminal is superimposed and transmitted to the transmission line 3. Then, the network management terminal 4
If the usage time of any one of the transmission paths 3 of the terminals 1 and 2 exceeds a predetermined time, an identification signal is extracted from the transmission signal transmitted by the terminal, and further, based on the extracted identification signal, The terminal corresponding to this identification signal is identified. Thus, in the maintenance system of this embodiment, the network management terminal
The terminal occupying the transmission line 3 for an abnormally long time can be easily located based on the respective identification signals superposed on the transmission signals sent by the respective terminals, and the maintenance person can promptly take the trouble. Can be dealt with.

The configuration and operation of the communication network maintenance system relating to such operation will be described in more detail below. FIG. 2 is a block diagram showing an embodiment of a detailed configuration of the communication network maintenance system in FIG. 1 according to the present invention. This figure particularly shows the transmitting circuit 9 and the receiving circuit 11 of the terminal 1 and the receiving circuit 1 of the network management terminal 4 in FIG.
8 shows details of No. 8. The transmitter circuit (described as TX in the figure) 9 includes a data input port 26 and a buffer (BU in the figure).
F) 27), and a transmission path coding circuit formed of a logic circuit for converting the “1” and “0” information sent from the terminal 1 of FIG. 1 into a code format suitable for the transmission path 3. (Described as COD in the figure) 28, for example, when the transmission path 3 is an optical fiber, a driver (described as DRV in the figure) 29 as a transmission path drive circuit configured by an electro-optical conversion circuit,
In accordance with the present invention, a high frequency generation circuit (described as HF in the figure) 30 that oscillates a frequency unique to the terminal 1 of FIG. And an identification signal superimposing circuit (indicated by “+” in the figure) 31 that is superimposed on the information coded by. The high frequency generation circuit 30 and the identification signal superposition circuit 31 constitute the identification signal superposition section of the present invention. The high frequency generation circuit 30 is composed of an oscillator that emits a sine wave of a specific frequency (f ₁ ), or a modulator and an oscillator that modulate a certain frequency as a carrier at another frequency. Also, in this figure, 32
Is a transmission enable signal input port, and based on this enable signal, the driver 29 is
A transmission signal is transmitted to the transmission line 3. The receiving circuit (described as RX in the drawing) 11 is a receiver (described as RCV in the drawing) that is a circuit that receives an electrical signal or an optical signal sent from another terminal to the transmission line 3 through the connection input port 23. )
33 and a transmission line coding / decoding circuit (described as DCD in the figure) 34 for performing a reverse conversion process to the above-mentioned transmission line coding circuit 28 and decoding a signal received by the receiver 33. The constructed and decoded signal is sent to the terminal body 7 of FIG. 1 via the data input port 35.
Receiver circuit for network management terminal (described as RXM in the figure) 18
Is a receiver (R in the figure, which is a circuit for receiving an electrical signal or an optical signal from the transmission line 3 through the connection input port 25.
CV) 36 and the above-mentioned transmission path coding circuit 28 perform reverse conversion processing, and a transmission path code decoding circuit (in the figure, which decodes the signal received by the receiver 36)
DCD) 37 and a signal received by the receiver 36 to extract a signal in a specific frequency band, that is, a so-called band pass filter, which is a high-frequency signal extraction filter as an identification signal extraction unit of the present invention (in the figure, FIL) 38, and a frequency identification circuit (described as FRC in the figure) 39 as a terminal identification unit of the present invention that identifies the terminal number by identifying the frequency of the signal extracted by the high frequency signal extraction filter 38. It is composed by. The frequency identification circuit 39 arranges as many narrow band filters as possible to pass only one of the frequencies for identifying the terminal, or selects a local level oscillator such as a selective level meter or a spectrum analyzer. For example, a method of sweeping the oscillation frequency to identify the incoming frequency is used. The terminal identification result by the frequency identification circuit 39 and the signal decoded by the transmission line code decoding circuit 37 are the data output port 40 and the terminal identification signal output port 41, respectively.
1 to the network management terminal body 16 of FIG.

The operation according to the present invention of the communication network maintenance system of this embodiment having such a configuration will be described below. First, in the transmission operation, in the terminal 1 of FIG. 1, the transmission information is input to the buffer 27 via the data input port 26 and then output from the buffer 27 according to a predetermined transmission control procedure. Then, the transmission path coding circuit 28 performs code conversion of the transmission information from the buffer and inputs it to the driver 29. At this time, the signal from the high frequency generation circuit 30 for generating the frequency (f ₁ ) previously assigned to the terminal 1 of FIG.
It is superimposed on the signal from the transmission line encoding circuit 28. Then, the superimposed transmission signal is sent to the transmission line 3 by the driver 29. Next, during reception operation, the terminal 1 of FIG.
In the above, the receiver 33 receives the signal transmitted to the transmission line 3, and the transmission line code decoding circuit 34 converts the transmission line code to identify whether the relevant information is addressed to the own station. To do. If it is addressed to its own station, it is sent to the terminal body 7 of FIG. 1 via the data input port 35, and
If not addressed to your own station, discard it.

On the other hand, in the network management terminal 4 of FIG. 1, first, similarly to the general terminal described above, the signal input to the receiver 36 is decoded into information by the transmission path code decoding circuit 37. At the same time, the high frequency signal extraction filter 3
In step 8, the high frequency signal superimposed by the transmitting terminal is extracted, and in the frequency identifying circuit 39, the extracted frequency is identified, and the terminal determined in advance in correspondence with the frequency is located. Here, a procedure in which the network management terminal 4 of FIG. 1 determines a terminal using the transmission line 3 as a failure and locates the terminal will be described. Originally, one terminal has a predetermined time zone (time slot)
Since the network management terminal 4 in FIG. 1 is given the right to transmit only during this period, the network management terminal 4 in FIG. 1 can determine that the terminal has an abnormality (failure) and is transmitting a signal for a long time. . That is, if the network management terminal 4 in FIG. 1 continuously observes a signal of a specific frequency indicating that the specific terminal is in a transmission state for a certain time or longer, that terminal is abnormal (failed). It can be determined that there is. Then, by identifying the continuously observed frequencies, as described above,
The faulty terminal can be located.

FIG. 3 is an explanatory diagram showing an embodiment of the frequency spectrum of the high frequency signal superimposed on the transmission path code transmitted to the transmission path of FIG. 1 and corresponding to each terminal. This example, NRZ information transmission rate f ₀ as channel coding (No
n Return to Zero) code, an example of a frequency spectrum when the center frequency of the superimposed high frequency is 4f ₀ is shown. In this figure, 42 is a transmission path code spectrum, and 43 is a superimposed signal transmitted from all terminals. A spectrum, 43a, is a detailed spectrum of 43, showing an example in the case of the frequency interval Δf assigned to each terminal and the total number “10”. Of these, 44 is the frequency f ₁ shown as an example above. _On the left and right of f ₁ , there are frequencies assigned to other terminals. In the present embodiment, the center frequency position of the superimposed high frequencies is 4f ₀ , but the extraction characteristic of the high frequency filter and the S / N ratio in the spectral region of the transmission path code are shown. In consideration of the above, it is possible to set it at an arbitrary position that is an integral multiple of the information transmission rate f ₀ . Further, although the frequency assigned to each terminal is shown as a fixed value, the modulation frequency can be changed corresponding to each terminal. That is, the carriers are the same, for example, f ₁ , and this f ₁
Is modulated at another frequency, for example f ₁₀ , and this f
_{Let 10 be} the frequency assigned for terminal identification. According to this method, it is possible to identify not only when one terminal fails and occupies the transmission path, but also when a plurality of terminals fail. For example, the method of putting a code on f ₁ becomes indistinguishable when multiple failures occur.
Even if the carrier f ₁ is used in common, normally only one terminal is in a transmission state at the same time and a signal is sent out, so there is no concern that a beat failure will occur due to a slight difference in f _{1 of} each terminal.

As described above with reference to FIGS. 1 to 3, in the communication network control system of this embodiment, each terminal superimposes a signal having a frequency component unique to each terminal on the transmission signal. Then, the network management terminal can easily locate each terminal by extracting a signal having a frequency component unique to each terminal from the transmitted signal. The present invention is not limited to the embodiment described with reference to FIGS. For example,
In this embodiment, the case of a communication network having two terminals and one network management terminal has been described, but the same configuration is possible regardless of the number of terminals. Also, if another network management terminal is prepared for backup, and each network management terminal is provided with a high-frequency generation circuit and a superposition circuit like other terminals, the network management terminal itself fails. It is also possible to manage the network more safely and securely.

[0013]

According to the present invention, it is possible to easily locate a terminal that occupies a shared transmission line for a long time, quickly eliminate the cause of failure, and improve the performance of a communication network maintenance system. It is possible.

[0014]

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a configuration relating to the present invention of a communication network maintenance system to which the present invention is applied.

FIG. 2 is a block diagram showing an embodiment of a detailed configuration of the communication network maintenance system in FIG. 1 according to the present invention.

3 is an explanatory diagram showing an example of a frequency spectrum of a high-frequency signal superimposed corresponding to each terminal and a transmission path code transmitted to the transmission path of FIG. 1. FIG.

[Explanation of symbols]

1, 2 terminal 3 transmission line 4 network management terminal 5, 6 terminal transmission / reception circuit 7, 8 terminal body 9, 10 transmission circuit 11, 12 reception circuit 13, 14 terminal interface 15 network management terminal transmission / reception circuit 16 network management terminal body 17 Transmission circuit 18 Reception circuit 19 Terminal interface 20 to 22 Connection output port 23 to 25 Connection input port 26 Data input port 27 Buffer 28 Transmission line coding circuit 29 Driver 30 High frequency generation circuit 31 Identification signal superposition circuit 32 Transmission enable signal input port 33 Receiver 34 Transmission line code decoding circuit 35 Data input port 36 Receiver 37 Transmission line code decoding circuit 38 High frequency signal extraction filter 39 Frequency identification circuit 40 Data output port 41 Terminal identification signal output port 42 Transmission line code spectrum 43 Superposed signal Spectrum 43a details the spectrum 44 frequency _{f 1}

Claims (1)

(57) [Claims] 1. A plurality of terminals, each occupying one shared transmission path at an arbitrary time and transmitting information by a transmission signal, and one of the plurality of terminals have a predetermined time. Beyond that, it detects that it has occupied the above transmission path,
In a communication network maintenance system including a network management terminal that detects the occurrence of a failure in the transmission path, each of the plurality of terminals has a frequency unique to each of the transmission signals sent to the transmission path. The identification signal superimposing means for superimposing the identification signal having the component, and transmitting the information to the transmission path by the transmission signal on which the identification signal superimposing means superimposes the identification signal. Identification signal extraction means for extracting the identification signal from the transmission signal received via the terminal, and terminal identification means for identifying the terminal corresponding to the identification signal based on the identification signal extracted by the identification signal extraction means. Maintenance of the communication network, characterized in that when detecting an excess of the occupation time of the transmission path by any of the plurality of terminals, the terminal that has exceeded the occupation time of the transmission path is located. Stem.