JPH0758769A - Invalid signal removing method for ring type optical communications network - Google Patents

Abstract

PURPOSE:To quickly remove an invalid signal even when invalid data such as a noise are induced a network by allowing a node which receives the signal of a preliminarily set condition to interrupt the network in a prescribed time, and remove the signal. CONSTITUTION:When a timer is activated and an input signal is not ended within a prescribed time, a first timer function 4a discriminates the input signal as the invalid signal, and interrupts the passage of a transmission signal in the prescribed time. A second timer function 4b interrupts the passage of the transmission signal in the prescribed time similarly to the first timer function 4a. The operating time of those first and second timer functions 4a and 4b is set according to the condition of the cable such as the passing time of one signal frame being the transmission signal, and the interrupting time is set so that, for example, a time when the same signal circulates through a cable 1A or 1B can be covered. Thus, the invalid signal such as the noise transmitted through the cables 1A and 1B except the proper signals can be removed from the network.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of removing an invalid signal in a ring type optical communication network, and particularly to operating a line by circulating noise which is a harmful invalid signal on the network with a simple structure. The present invention relates to a method of removing an invalid signal in a ring type optical communication network capable of preventing the interference of signals.

[0002]

2. Description of the Related Art LAN (Local Area Net)
In the work), there is a ring type network using an optical communication cable as shown in FIG. FIG. 5 exemplifies a network for packet communication by a token passing system of a dual communication line. In FIG. 5, reference numerals 1A and 1B denote optical fiber cables (hereinafter abbreviated as cables) for optical communication, which are ring-shaped and transmit optical signals in opposite directions. The arrows shown in the cables 1A and 1B indicate the signal transmission directions. A plurality of nodes 1a 'and 1b', which are predetermined information processing devices, are coupled to the cables 1A and 1B. Fig. 5
Shows only the first node 1a 'and the second node 1b'. On the cables 1A and 1B, tokens and data signals carrying necessary information are transmitted in the opposite directions to the respective nodes.
It is circulated and transmitted while being relayed by a cable. An outline of one frame, which is a series of signals transmitted as a data signal, is constituted by a format F as shown in FIG. 4, for example. In FIG. 4, the left side shows the start bit of the data signal, and the data signal is the header control code H, from the beginning.
Address code A, signal D, indicating destination and source
The frame check sequence C for signal check is arranged in this order. The data signal has a maximum length of 32 bits, for example. Therefore, the node that matches the address code indicating the destination takes in the signal, and the node that does not match the address code indicating the destination directs the received signal to the next node as it is. Send. When the destination node receives the same signal through the cable in the opposite direction, the data signal received later is discarded in the received node. Also, the node that has the signal to be transmitted is
When it receives Kun, it sends the same data signal to both cables 1A and 1B. If the signal to be transmitted does not fit in one frame, it is transmitted in multiple times. When the transmission is completed, the token is transmitted to the next node. If a token is received and there is no signal to send, the token is sent to the next node. It also has a function of monitoring the cables 1A and 1B in order to detect disconnection of the cables. That is, if a data signal is received from either the cable 1A or 1B and a data signal from another cable is not received, it is determined that the cable on the non-receiving side is broken.

[0003]

In the ring type optical communication network as described above, the cable itself is very strong against electric noise and is not affected, but the optical link module is not affected. The photoelectric conversion element that constitutes the light receiving function of the module is weak against noise because it handles weak electric signals. Therefore, the noise generated in the photoelectric conversion element may be directly transmitted to the next cable as an invalid signal. Depending on the timing of the generation of the invalid signal such as noise and the time length of the invalid signal such as noise, it may be deleted depending on the characteristics of the transmission / reception function in each node, but depending on the conditions, the optical communication network may be deleted. There was a risk that noise would circulate and interfere with legitimate signal communication. Further, if noise is transmitted only in one direction of the double cable and noise is not transmitted in the other direction, there is a problem that the disconnection detection function may determine the disconnection. The present invention has the above-mentioned conventional problems (problems)
Even when an ineffective signal such as noise is induced in the network, the ineffective signal is promptly removed to prevent the ineffective signal from circulating on the network. It is an object of the present invention to provide a method for removing an invalid signal in a ring type optical communication network capable of preventing malfunction.

[0004]

In order to solve the above problems, in the invalid signal removing method in the ring type optical communication network according to the present invention, the node receiving the signal of the preset condition is This network was cut off for a predetermined time to remove this signal. This signal is
It is desirable that the signal has a length longer than a preset time. Further, it is desirable that the above-mentioned cutoff time is at least the time for the signal to make one round on the network. Furthermore, when the network is cut off for a predetermined time, the correctness of the received signal is judged, and when it is positive, the time is judged to be positive,
In the case of no, it is desirable to carry out until the reception signal is completed.

[0005]

According to the present invention, as described above, the node which receives the signal of the preset condition is designed to be set as an invalid signal because the network is cut off for a predetermined time to remove this signal. The generated signal is easily removed and there is no risk of circulating on the network. Further, by setting this signal as a signal for a preset time or more, a harmful invalid signal can be easily discriminated from a valid data signal. Further, the communication function can be restored in a short time by setting the cutoff time to at least the time for the signal to make one round on the network. Also, if the correctness of the received signal is judged and if it is positive, the time is judged to be positive, and if not, the network is cut off until the received signal is completed. You can keep it to the limit.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of removing an invalid signal in a ring type optical communication network according to the present invention will be described in detail with reference to the drawings. FIG. 3 shows an example of a packet communication network based on the double cable token passing communication system. In FIG. 3, 1A and 1B are ring-shaped cables for transmitting optical signals in opposite directions.
The arrows on the cables 1A and 1B indicate the signal transmission directions. Each of the cables 1A and 1B has a plurality of nodes which are predetermined information processing devices, such as 1a and 1
b, 1c and 1d are combined. In addition, in FIG.
Each node is marked. On the cables 1A and 1B, token and data signals are circulated and transmitted in the opposite directions while being relayed at each node. The outline of one frame, which is a series of signals transmitted as a data signal, is constituted by a format as shown in FIG. 4, for example. In FIG. 4, the left side shows the start bit of the data signal F. The data signal is the header control code H from the beginning, the address code A indicating the destination and the source, the signal D, the signal. The frame check sequence C for checking is transmitted in this order. The data signal F has a maximum length of 32, for example.
It is configured into bits, and it takes, for example, 3 msec to receive 32 bits.

Embodiment 1 FIG. 1 is a block diagram showing a method of applying an invalid signal removing method in a network for packet communication by a double cable token passing / cyclic broadcast communication system according to the present invention. -Shows an example of the main circuit in C. It should be noted that illustration of element functions, signal lines, and the like not directly related to the present invention is omitted. In FIG. 1, 1A
And 1B are ring-shaped first and second cables for transmitting optical signals in opposite directions.
b is a transmission and reception system that converts an electrical signal carrying a signal to be transmitted into an optical signal and puts it on a cable, and receives optical communication transmitted from the cable and converts it into an electrical signal. It is a first and second optical signal link having a function. First case
The respective arrows on the cable 1A and the second cable 1B indicate the signal transmission direction. First optical signal link 2
The signal received by a is shaped by the first waveform shaping circuit 3a and is input to the first timer function 4a, the first multiplexer 5a, the signal disconnection detection function 8 and the first-arrival priority determination function 9, which will be described in detail later. The signal received by the second optical signal link 2b is shaped by the second waveform shaping circuit 3b, and a second timer function 4b and a second multiplexer 5 which will be described in detail later.
b, signal disconnection detection function 8 and first-arrival priority determination function 9. The output of the first timer function 4a and the output of the first multiplexer 5a are supplied to the first transmission cutoff function 6a and the second output.
The output of the timer function 4b and the output of the second multiplexer 5b are input to the second transmission blocking function 6b. The output of the first transmission cutoff function 6a is input to the output function section of the second optical signal link 2b, and the second transmission cutoff function 6b is input.
Is output to the output function unit of the first optical signal link 2a. The outputs of the signal disconnection detection function 8 and the first-arrival priority determination function 9 are input to the main functional section 10 of this node. The main function unit 10 has a basic function and a management function in this node. The first multiplexer 5a and the second multiplexer 5b described above are operated by the output signal from the main functional unit 10 of this node.

Next, the function of the above configuration will be described. The main functional unit 10 of each node having transmission data is
When the token arrives, the data to be transmitted is always held, and when the token arrives, the held data is created in the signal frame of the format shown in FIG. The second optical signal link 2b is operated by operating the second multiplexer 5b.
To the first cable 1A via the first optical signal link 2
The data is transmitted on the second cable 1B via a. When the predetermined signal transmission is completed, the token is transferred to the next node.
Send to do. The signal transmitted through the first cable 1A and received by the first optical signal link 2a is the first waveform shaping circuit 3a.
And is input to the first timer function 4a, the first multiplexer 5a, the signal disconnection detection function 8 and the first-arrival priority determination function 9. The first timer function 4a has a function of discriminating the invalid signal according to a preset condition. That is, when a signal is received according to a preset condition, a predetermined time, for example, the signal frame length is 3 ms.
In the case of ec, a timer of (3 + α) msec is started. When the reception signal is completed during the operation of the timer, the subsequent operation of the first timer function 4a is not executed. That is, if the input signal is a signal frame with a maximum length of 3 msec,
The timer function 4a does not execute the subsequent functions and does not transmit a predetermined signal to the first transmission blocking function 6a. The first transmission blocking function 6a is configured so that the transmission blocking function does not function unless a signal is input from the first timer function 4a. Therefore, the first multiplexer 5a outputs the input signal to the first cable 1A via the second optical signal link 2b according to the operation from the main function unit 10. Similarly, the signal transmitted through the second cable 1B and received by the second optical signal link 2b is shaped by the second waveform shaping circuit 3b, and then the second timer function 4b and the second multiplexer 5b. And the signal disconnection detection function 8 and the first-arrival priority determination function 9. In the second timer function 4b, when a signal is received similarly to the first timer function 4a, a predetermined time, for example, (3 + α) when the signal frame length is 3 msec.
Start the msec timer. When the reception signal is completed during the operation of the timer, the subsequent operation of the second timer function 4b is not executed. That is, when the input signal is a signal frame with a maximum length of 3 msec, the second timer function 4b does not execute the subsequent functions and does not transmit the predetermined signal to the second transmission blocking function 6b. The second transmission blocking function 6b, like the first transmission blocking function 6a, is configured so that the transmission blocking function does not function unless a signal is input from the second timer function 4b. Therefore, the second multiplexer 5b outputs the input signal to the second cable 1B via the first optical signal link 2a in accordance with the operation from the main function unit 10.

In the first-arrival priority judging function 9, a signal transmitted through the first cable 1A and the second cable 1 arrives.
In the case where the signals transmitted by B and arrived are the same, the first-arriving signal is transmitted to the main functional unit 10 and the last-arriving signal is discarded. In the signal disconnection detection function 8, the first
Signal transmitted through the second cable 1A and the second cable 1B
If any of the transmitted signals are not received,
It is determined that the cable not received is disconnected, and the predetermined disconnection response function provided in the main function unit 10 is activated. The first timer function 4a determines that the input signal is an invalid signal if the input signal is not completed within a predetermined time, for example, (3 + α) msec after the timer is started as described above.
A predetermined signal is output to the transmission blocking function 6a to block passage of the transmission signal for a predetermined time. The second timer function 4b is also the first
Similar to the timer function 4a, the passage of the transmission signal is blocked for a predetermined time. Each of the above-mentioned first and second timer functions 4a, 4
The operation time of b is set according to the passage time of one signal frame which is a transmission signal and other conditions of this cable, and the interruption time is, for example, the time for which the same signal circulates through the cable 1A or 1B. Set to cover. By the above operation, the invalid signal such as noise that is transmitted by the cable other than the appropriate signal is removed from the network. As a result of the above operation, the regular signal for one time is also discarded, but since this communication system uses the cyclic broadcast communication system as described above, the same signal is continuously transmitted, and this communication system Does not interfere with the function of. Further, since the function of the signal disconnection detection function 8 described above is set in accordance with the operation of each of the first and second timer functions 4a and 4b described above, the first timer function 4a or the second timer function 4 is set.
The signal discarded by any of the operations of b does not function even if it is an input from either the first cable 1A or the second cable 1B.

Example 2: FIG. 2 shows a double case according to the present invention.
2 shows an example of a main circuit of a node to which the invalid signal removing method in a packet communication network by the Bull token-passing system is applied. It should be noted that illustration of element functions that are not directly related to the present invention is omitted. The second embodiment describes an example in which the first embodiment shows an example of the cyclic broadcast communication system, while the second embodiment is applied to other ordinary communication systems. In FIG. 2, 1A and 1B are ring-shaped first and second cables for transmitting optical signals in opposite directions, and 2a and 2b are electrical signals carrying signals to be transmitted. Convert to signal
The first and second optical signal links have a function of mounting on a cable and receiving an optical communication transmitted from the cable and converting the optical communication into an electric signal. First cable 1A, second cable
The arrows respectively indicated on the bull 1B indicate the signal transmission directions. The signal received by the first optical signal link 2a is shaped by the first waveform shaping circuit 3a and input to the first abnormal signal determination processing function 11a, the signal disconnection detection function 8 and the first-arrival priority determination function 9. The signal received by the second optical signal link 2b is shaped by the second waveform shaping circuit 3b, and the second abnormal signal determination processing function 11b and the signal disconnection detection function 8
To the first-arrival priority determination function 9. The output of the first abnormal signal determination processing function 11a is input to the first multiplexer 7a, and the output of the first multiplexer 7a is input to the output function unit of the second optical signal link 2b described above. The output of the second abnormal signal determination processing function 11b is input to the second multiplexer 7b, and the output of the second multiplexer 7b is input to the output function unit of the first optical signal link 2a described above. The outputs of the signal disconnection detection function 8 and the first-come-first-served determination function 9 are respectively the main functional units 10 of this node.
Are typing in. The first multiplexer 7a and the second multiplexer 7b described above are operated by the output signal from the main functional unit 10 of this node.

Next, the function of the above configuration will be described.
The main functional unit 10 of each node holds a signal to be transmitted at all times, and when the token arrives, the held signal is created in the signal frame of the format shown in FIG. By operating the multiplexer 7a and the second multiplexer 7b, the second
To the first cable 1A via the optical signal link 2b, to the second cable 1B via the first optical signal link 2a,
Each is transmitted. When the signal transmission is completed as described above, the token is sent to the next node. First case
The signal transmitted through the first optical signal link 2a after being transmitted through the bull 1A is shaped by the first waveform shaping circuit 3a, and is processed by the first abnormal signal determination processing function 11a, the signal disconnection detection function 8 and the first-arrival priority determination function 9. To enter. Similarly, the signal transmitted through the second cable 1B and received by the second optical signal link 2b is shaped by the second waveform shaping circuit 3b, and the second abnormal signal determination processing function 11b and signal disconnection detection are performed. Input to the function 8 and the first-come-first-served determination function 9. In the first-arrival priority determination function 9, if the signal transmitted by the first cable 1A and arriving is the same as the signal transmitted by the second cable 1B, the first-arrival signal is sent to the main functional unit 10. Discard the signal that was transmitted and arrived later. In the signal disconnection detection function 8, the signal transmitted through the first cable 1A and the second
If any of the signals transmitted through the cable 1B does not arrive, it is determined that the cable that has not arrived has disconnected, and the predetermined disconnection response function provided in the main function unit 10 is activated. First
The abnormal signal judgment processing function 11a of FIG. 4 has an abnormal signal judgment function, and the frame check sequence C or the like provided in this signal frame is used for the input signal like the format shown in FIG. Check, if the signal is legitimate, the first
To the multiplexer 7a. The first multiplexer 7a outputs the input signal to the first cable 1A via the second optical signal link 2b according to the operation from the main function unit 10. First abnormal signal determination processing function 11a
When it determines that the input signal is abnormal, it discards this received signal. That is, this network is shut off for a time corresponding to the transmission time of the received signal according to preset conditions. Similarly, the second abnormal signal judgment processing function 11b is also provided with an abnormal signal judgment function, and checks the frame check sequence C etc., and if it is a normal signal,
When the signal is transmitted to the second multiplexer 7b and it is determined that the signal is abnormal, the received signal is discarded. That is, this network is shut off for a time corresponding to the transmission time of the received signal according to preset conditions. By the above operation, the signal component such as noise that is transmitted in a cable other than the appropriate data signal is determined to be an invalid signal according to a preset condition, and is removed from the network.
Since the function of the signal disconnection detection function 8 described above is set according to each operation of the first abnormality determination processing function 11a and the second abnormality determination processing function 11b, the first abnormality determination processing function 11a or the first abnormality determination processing function 11a or The signal discarded by one of the operations of the abnormality determination processing function 11b of 2 is the first cable 1
Input from either A or the second cable 1B does not work.

The above description shows the basic method and configuration for realizing the technical idea of the present invention, and it is needless to say that various application modifications can be made. Further, it goes without saying that the same can be applied to a communication system having a configuration of elements other than those described above according to the embodiment.

[0013]

Since the present invention is a method as described above, it has the following excellent effects. Unnecessary signals such as invalid signals that may interfere with useful signals are removed, and there is no risk of circulating on the network. By determining a signal component of a preset time or more as an invalid signal, it is possible to easily discriminate a useful data signal from a signal component such as invalid noise. At least the time to shut off the network
The time required for signal removal can be shortened by setting the time for the signal to make one round. Therefore, there is no risk of interfering with necessary communication functions. If the time to shut off the network is determined to be positive if the received signal is positive, and if it is negative until the received signal is completed, the time to shut off the network may be limited to the necessary minimum limit. it can. Therefore, there is no risk of interfering with necessary communication functions. Since the invalid signal is removed from the network, malfunction of the disconnection detection function can be prevented.

[Brief description of drawings]

FIG. 1 is a first embodiment of the present invention in one node to which an invalid signal removing method in a packet communication network by a double cable token passing / cyclic broadcast communication system is applied. It is a general | schematic block diagram which has shown the example of a main circuit.

FIG. 2 shows an example of a main circuit in one node to which an invalid signal removing method in a packet communication network by a double cable token passing system according to a second embodiment of the present invention is applied. FIG.

FIG. 3 is an explanatory diagram showing an example of a packet communication network according to a double cable token passing communication system to which the present invention is applied.

FIG. 4 is an exemplary diagram of a signal frame format used in a packet communication network to which the present invention is applied.

FIG. 5 is an explanatory diagram illustrating a network for packet communication using a double cable token passing system.

[Explanation of symbols]

 1A, 1B: cable (optical fiber cable) 2a, 2b: optical signal link 3a, 3b: waveform shaping circuit 4a, 4b: timer function 7a, 7b: multiplexer 6a, 6b: transmission cutoff function 8: signal disconnection detection Function 9: First-come-first-served judgment function 10: Main function part 11a, 11b: Abnormality judgment processing function

Claims (4)

[Claims] 1. In a ring type optical communication network,
A method for removing an invalid signal in a ring type optical communication network, characterized in that a node receiving a signal of a preset condition interrupts the network for a predetermined time to remove the signal. 2. A method for removing an invalid signal in a ring type optical communication network, wherein the signal of the preset condition according to claim 1 is a signal component of a preset time or more. 3. A method for removing an invalid signal in a ring type optical communication network, wherein the time for interrupting the network according to claim 1 is at least the time for a signal to make a round around the network. 4. When the network according to claim 1 is cut off for a predetermined time, whether the received signal is correct or not is determined, and if positive, the time is determined to be positive, and if not, until the received signal is completed. , A method of eliminating invalid signals in a ring type optical communication network which is performed.