JPH0529179B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an automatic loop network failure avoidance method for automatically avoiding failures in a loop network.

(Prior Art) As is well known, a loop network is one in which a plurality of nodes are arranged on a circular transmission path, and the communication node signal relay section of each node takes in signals from the upstream transmission path to the node, and also connects the nodes to each other. A signal is sent from the upstream transmission path to the downstream transmission path, and the signal is further interrupted from the upstream transmission path to the downstream transmission path.

By the way, in this kind of loop network,
The transmission line is made up of metal cables and optical fiber cables, but in preparation for failures such as transmission line breaks, the circular transmission line is duplicated, and a central monitoring and control unit is installed, which relays the communication node signal of each node. Bypass control that centrally monitors the operating status of each section individually, determines the location where a failure occurs, and sets a predetermined communication node signal relay section to a bypass state, and the transmission path is looped back at a predetermined communication node signal relay section. It is possible to carry out loopback control to make this happen.

(Problems to be Solved by the Invention) In the conventional loop network failure avoidance method described above, it is necessary to provide an individual control line from the central monitoring control unit to the signal relay unit of each node separately from the transmission path, and the wiring Costs increase. In addition, the centralized monitoring and control unit performs various complex controls such as determining the location of a failure and individually controlling the communication node signal relay unit of each node depending on the failure status. There are problems such as complicating the device configuration and complicating the loop network configuration.

The present invention was devised in view of these conventional problems, and its purpose is to improve the loop network by enabling loopback control and bypass control to be performed at the communication node signal relay section of each node at its own discretion. An object of the present invention is to provide an automatic loop network failure avoidance method that can automatically avoid failures without complicating the configuration of the network.

(Means for Solving the Problems) In order to achieve the above object, the loop network fault automatic avoidance system of the present invention has the following configuration. That is, the loop network failure automatic avoidance method of the present invention is a loop network in which one control node and a plurality of communication node signal relay sections are arranged on two ring transmission paths whose signal transmission directions are opposite to each other. Each of the control node and the plurality of communication node signal relay units has a first input terminal, a first output terminal, a second input terminal, and a second output, respectively corresponding to two transmission paths. Immediately after power is turned on, the control node is in a bypass state in which both the first input/output terminal and the second input/output terminal are internally connected for communication signals; By connecting a signal generator and this control signal generator to either the first output terminal or the second output terminal, a control signal is sent to the transmission line, and the sent control signal is transmitted for a predetermined period (for example, a loop). a switching means for transmitting a control signal from the other output terminal if the input is not input to the corresponding input terminal after a period (slightly longer than the period required for one round); When a control signal generator is connected to one of the output terminals, the control signal is controlled between the other output terminal and the corresponding input terminal until a control signal is input to the input terminal corresponding to that output terminal. When the internal connections are such that signals can pass through, and the control signal input to the input terminal corresponding to one of the output terminals is earlier than the control signal input to the input terminal corresponding to the other output terminal. and a first connection control means that cancels the internal connection state, and conversely continues the internal connection state at a later time; in a normal state, each communication node signal relay section first transmits the control signal. A control signal is taken into the node side from the input terminal to which the input was applied, and the control signal is sent to the output terminal corresponding to the input terminal to which the control signal was input first, and the control signal is sent to the first input terminal or the second input terminal. If the control signal is input to one of the input terminals, and the state in which no control signal is input to the other input terminal continues even after the predetermined period has elapsed, the control signal is input to one of the input terminals. internally connecting an output terminal corresponding to one of the other input terminals and setting the communication node signal relay section to a loopback state, and when a control signal is input to one of the other input terminals after the predetermined period has elapsed; To cancel the loopback state and internally connect one of the other input terminals to the corresponding output terminal, and even if a control signal is input to one of the input terminals, the node is connected to the corresponding output terminal. If there is no signal sent from the side and no control signal is input to either of the other input terminals, one of the input terminals is internally connected to the output terminal corresponding to the other input terminal, and the corresponding communication Setting the node signal relay section to a loopback state, internally connecting one of the input terminals to the corresponding output terminal, and even if a control signal is input to one of the input terminals, the corresponding output terminal If there is no signal sent from the henode side and a control signal is input to one of the other input terminals, either one of the input terminals and its corresponding output terminal and either of the other input terminal and the Connect the corresponding output terminals internally and set the signal relay section to bypass state, and if there is no control signal input to any input terminal, the state immediately after the power is turned on (the connection between the input and output terminals is The loop network failure automatic avoidance method is characterized by comprising a second connection control means for returning to a connected bypass state.

(Operation) Next, the operation of the loop network fault automatic avoidance system of the present invention configured as described above will be explained.

The two circular transmission lines consist of a clockwise transmission line ( ) and a counterclockwise transmission line ( ). In addition, the control node and three communication node signal relay sections A, B,
Assume that the Cs are arranged in this order from the upstream side to the downstream side, for example, in the case of a transmission line ().

Loop network failures include failures that occur on either the transmission line () or the transmission line (), failures that occur simultaneously on both the transmission line () and the transmission line (), and failures that occur between the communication node signal relay section and its nodes. The following case will be explained as an example.

For example, when a transmission failure occurs in the transmission path ( ) between communication node signal relay units A and B, failure avoidance is performed as follows.

In the control node, a control signal generator is connected to the first and output terminals, for example, and a control signal is sent to the transmission line (). At this time, in the control node, the second output terminal and the second input terminal are internally connected so that the control signal can pass therethrough until the control signal is input to the first input terminal.

The control signal sent to the transmission line () is taken into the node side via the first input terminal of the communication node signal relay section A, and is sent from the node side to the transmission line () via the first output terminal. Ru. However, this control signal is not transmitted to communication node signal relay section B and beyond.

Next, the control node stops sending the control signal to the transmission path () after a predetermined period of time (for example, a period slightly longer than the period required for one loop) and switches to sending the control signal to the transmission path ().

By this switching, the communication node signal relay section A returns to its initial state, that is, the state immediately after the power is turned on, which is a bypass state in which the input and output terminals are internally connected. Further, in the control node, the first input terminal and the first output terminal are internally connected so that a control signal can pass therethrough.

Transmission line () from the second output terminal of the control node
The control signal sent to the communication node signal relay section C
The signal is taken into the node side through the second input terminal of the node, and is sent out from the node side to the transmission path ( ) through the second output terminal and reaches the communication node signal relay section B.
A similar process is followed in the communication node signal relay section B, and the signal is inputted to the second input terminal of the control node via the communication node signal relay section A. This eliminates the internal connection between the first input terminal and the first output terminal that allows the control signal to pass through the control node.

In addition, in the communication node signal relay sections C, B, and A, since there is no control signal input to the first input terminal even after a predetermined period has elapsed, the second input terminal and the first output terminal are internally connected to each other. The communication node signal relay section is set to a loopback state. As a result, the control signal sent by the signal relay section C from the first output terminal to the transmission line () reaches the control node, but does not enter the first input terminal of the communication node signal relay section A, so The node signal relay section A continues to be in a loopback state. Furthermore, since there is no input to the first input terminal in the communication node signal relay section B, the loopback state continues in the same way. In the communication node signal relay section C, since the control signal is input to the first input terminal, the loopback state is canceled and the first input terminal and the first output terminal are internally connected.

In this way, the route of the control signal is taken from the second output terminal of the control node to the node side via the transmission line ( ) and the second input terminal of the communication node signal relay section C, and from the node side. The signal is taken into the node side via the second output terminal of the communication node signal relay section C, the transmission line ( ), and the second input terminal of the communication node signal relay section B. On the other hand, the control signal that enters the second input terminal of the communication node signal relay section B is turned back and sent to the first output terminal, the transmission line (),
The signal relay unit C returns to the first input terminal of the control node via the first input terminal, the first output terminal, and the transmission line (), and the communication node signal relay unit B
The control signal taken into the node side is sent to the second output terminal of the communication node signal relay section B, the transmission line (),
The communication node signal is input to the node side through the second input terminal of the communication node signal relay section A, and is transmitted from the node side to the second output terminal of the communication node signal relay section A and the second output terminal of the control node via the transmission line (). is transmitted to the input terminal of In short, communication node signal relay section A,
Even if there is a failure in the transmission line () between the two, a loop network can be formed that automatically avoids the transmission line (). Other failure modes,
Similarly, this can be automatically avoided at the point where it occurs.

As described above, according to the loop network fault automatic avoidance method of the present invention, each communication node signal relay section puts itself into a loopback state, Since it can be set to bypass status or relay status, the network as a whole can automatically avoid various network failures.
It is possible to eliminate the need for a centralized monitoring control unit that was conventionally required. Therefore, there is no need for a control line provided separately from the transmission line in each communication node signal relay section, which has the effect of simplifying the configuration of the loop network.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of a loop network to which the present invention is directed. This loop network is 1
One control node 1 and a plurality of communication node signal relay sections 2, 3, 4, 5, and 6 are arranged in two circular transmission paths 7 and 8 whose signal transmission directions are opposite to each other. , each of the control node and the plurality of communication node signal relay sections has a first input terminal 1 and a first output terminal O1, a 26th input terminal I1 and a second output corresponding to the two transmission paths, respectively. It has a terminal O2. Here, the annular transmission line 7 is assumed to be a clockwise system, and the annular transmission line 8 is assumed to be a counterclockwise system.

Immediately after the power is turned on, the control node 1 is in a bypass state in which both the first input/output terminal and the second input/output terminal are internally connected for communication signals, and the control signal generator 9 Although not shown, the switching means and first connection control means operate as shown in FIG. 2.

Further, the communication node signal relay section (2 to 6) is a third
A second connection control means is provided which operates as shown in the figure.

In FIG. 2, the switching means switches the control signal generator 9 to the first output terminal O1 or the second output terminal O2, as shown in FIGS. 2b to 2e and _2f to i. The control signal is then connected to one of the output terminals, and the control signal is sent to the transmission line corresponding to the output terminal. This switching operation, for example,
When a control signal is sent to the annular transmission line 7 from the output terminal O1 of the control signal and is not input to the first input terminal I1 even after a predetermined period of time (for example, a period slightly longer than the period of one round of the loop), As a result, when there is no control signal input, both output terminals are switched alternately. Note that the control signal is, for example, a continuous signal of meaningless data or a signal repeating at a constant period.

The first connection control means generates a control signal at either the first output terminal O1 or the second output terminal O2 after the power is turned on, although it is as shown in FIG. 2a when the power is turned off. When the device 9 is connected, in the initial state, the first input terminal I
Since there is no control signal input to the first and second input terminals I2, the second input terminal and the second output terminal, and the first input terminal and the first output terminal are controlled as shown in FIG. 2b and f. Connect internally so that signals can pass through. When a control signal is input to the input terminal corresponding to the output terminal to which the control signal generator 9 is connected, if no control signal is input to the uncorresponding input terminal at that time (Fig. 2 c, g ), or even if a control signal is subsequently input to an uncorresponding input terminal (Fig. 2 d, h), the internal connection state is canceled, and there is no control signal input to the corresponding input terminal, and the uncorresponding input terminal is When a control signal is input, the internal connection state continues as shown in FIG. 2e or 2i. As shown in FIG. 2 e' and j, even if a control signal is subsequently input to the corresponding input terminal, the internal connection state is maintained as is.

Next, the operation of the second connection control means will be explained with reference to FIG. Note that this figure assumes that the annular transmission line 8 is a backup system.

FIG. 3a shows the initial state. When a control signal is sent to the circular transmission line 7, as shown in FIG. 3b, the control signal is taken in from the first input terminal I1 to the node side, and the control signal is sent from the node side to the first output terminal O1. However, if the second input terminal I2 is in a no-signal state when the control signal is input to the first input terminal I1, for example, until the time _T1 , which is slightly longer than the time required for one loop, has elapsed. The interval is the third
As shown in Figure 3b, it is the same as the initial state (Figure 3a), but after time T ₁ has passed, the first state is as shown in Figure 3c.
The input terminal I1 and the second output terminal O2 of the communication node are internally connected to set the communication node signal relay section to a loopback state.

Then, when a control signal is input to the second input terminal I2, the loopback state is canceled and the second input terminal I2 and the second output terminal O2 are internally connected, as shown in FIG. 3d. Note that FIG. 3e shows a state corresponding to FIG. 3d when a control signal is sent to the annular transmission line 8.

Next, FIGS. 3f and 3g or 3h and 3i show the case where a transmission failure occurs between the node and the communication node signal relay section.

First, in Fig. 3 f or Fig. 3 h, there is a control signal input to one of the input terminals, but the signal transmission from the node side to the corresponding output terminal is interrupted, and the control signal is not sent to the other input terminal. If there is no input, one of the input terminals is internally connected to the output terminal corresponding to the other input terminal, the signal relay section is set to a loopback state, and one of the input terminals and the corresponding output terminal are connected internally. This figure shows how the output terminals are connected internally. In addition, in Figure 3g or Figure 3i, a control signal is input to one of the input terminals, but the signal transmission from the node side to the corresponding output terminal is interrupted, and the control signal is sent to one of the other input terminals. If there is an input, the terminals of one of the input terminals and its corresponding output terminal are internally connected to each other, and the terminals of the other input terminal and the corresponding output terminal are internally connected to each other and the signal relay section of the communication node is bypassed. This shows how to set the status.

Next, the automatic failure avoidance operation of the loop network will be explained with reference to FIGS. 4 to 7. In addition,
The control node 1 is configured to perform the operations of the switching means and the first connection control means at the time of power-on and at appropriate repeated times thereafter, or continuously from the time of power-on.

FIG. 4 shows the state transition of the transmission line when the loop network is normal. The control signal generator 9 is connected to the first output terminal O1 of the control node 1;
The control signal is transmitted through the circular transmission path 7 to the communication node signal relay sections 2, 3, 4, 5, and 6 (Fig. 4a), and the control signal is transmitted from the communication node signal relay section 6 to the control node 1. When inputting to the first input terminal, the fourth
As shown in Figure b, in the control node 1, the internal connection that allows the control signal to pass between the second input terminal and the second output terminal is canceled, and the communication node signal relay section (2 to 6) is in a loopback state. Become.

As shown in FIG. 4c, in the communication node signal relay section 6, since the second input terminal I2 is in a no-signal state, the loopback state continues, and the other terminals are released from the loopback state, and two transmissions are performed as shown by the solid line. One transmission path is formed by forming a ring.

After that, in the control node 1, the control signal generator 9 is connected to the second output terminal O2, so that the control signal input can also be confirmed at the second input terminal I2 in the communication node signal relay section 6, and the loop network is connected to the first output terminal O2. It returns to the normal state as shown in the figure.

Next, FIG. 5 shows the state transition when a failure occurs in the ring transmission line 7. After confirming the normality of the loop network as shown in Figure 4c,
As shown in FIG.
Since the control signal input to I2 is interrupted, the control node 1 switches the connection of the control signal generator 9 after a certain period of time has elapsed. Since no control signal is sent to the transmission line during this switching operation, the signal relay sections (2 to 6) return to the initial state in response to the disappearance of the control signal (FIG. 5b).

When the control node 1 completes the connection switching of the control signal generator 9, the control signal goes around the circular transmission line 8 once (Fig. 5c), and after the first round, the control signal goes through the communication node signal relay section (2 to ) are in a loopback state (Fig. 5d).

In the communication node signal relay sections 2 and 4, since the first input terminal I1 is in a no-signal state, the loopback state continues. In addition, since the control signal is input to the first input terminal I1 in the communication node signal relay sections 3, 5, and 6, the loopback state is canceled and the first input terminal I1 and the first output terminal O1 are internally connected. . As a result, as shown in FIG. 5e, one transmission path is formed that avoids the transmission path in which the failure has occurred.

Next, FIG. 6 shows the state transition when a failure occurs in the ring transmission lines 7 and 8. After a normal loop network as shown in FIG. 1 switches the connection of the control signal generator 9 (FIG. 6a→FIG. 6b→FIG. 6c). In this case, the control signal reaches from the communication node signal relay section 6 to the communication node signal relay section 5, and since the second input terminal I2 of the control node 1 is in a no-signal state, the first input terminal I1 and the first output terminal O1 are controlled. They are interconnected so that signals can pass through them (Fig. 6c).

Then, in the communication node signal relay section 6, the second input terminal I2 and the first output terminal O1 are internally connected to enter a loopback state, but in the communication node signal relay section 5, the first input terminal I1 is disconnected. Since it is in the signal state, the loopback state continues.

As a result, in the communication node signal relay unit 6, a control signal is input to the first input terminal I1, the loopback state is canceled, and the first input terminal I1 and the first output terminal O1 are internally connected. Therefore, the control signal is turned back at the communication node signal relay section 5 and reaches the communication node signal relay section 4, as shown in FIG. 6d. Next, the communication node signal relay units 2, 3, and 4 perform connection control in the same manner as described above.
The communication node signal relay unit 4 continues the loopback state, and the communication node signal relay units 2 and 3 internally connect the second input terminal I2 and the second output terminal O2,
As shown in FIG. 6e, the loop network is formed by avoiding the transmission path where the failure has occurred. Note that in the control node 1, since the control signal is input to the second input terminal I2 after the control signal is input to the first input terminal I1, the internal connection state that allows the control signal to pass continues.

Finally, FIG. 7 shows the state transition when a node failure occurs. The premise is the same as above, and the seventh
If a failure occurs between the communication node signal relay section 3 and its node as shown in FIG. Therefore, as shown in FIG. 7B, in each communication node signal relay section (2 to 6), the second input terminal I2 is in a no-signal state, so that a loopback state occurs. At the same time, in the communication node signal relay unit 3, the first output terminal O1 becomes a no-signal state, so the first input terminal I1 and the first output terminal O1 are internally connected and the node side is disconnected.

Thereafter, as shown in FIG. 7c, the communication node signal relay section 3 enters a bypass state, and a loop network is formed in which node failures are avoided.

In summary, in each communication node signal relay section,
When the next control signal cannot be detected even after a certain period of time has elapsed, it is determined that some kind of failure has occurred, and the control signal is input to the third input terminal according to the input state of the control signal to the first input terminal I1 and the second input terminal I2. Predetermined obstacles can be avoided simply by switching as shown in the diagram.

(Effects of the Invention) As described above, according to the loop network fault automatic avoidance method of the present invention, one signal relay unit sends a control signal to the transmission unit, and the remaining signal relay units change their input/output status. Based on this, the network can be set to loopback, bypass, or relay status, allowing the network as a whole to automatically avoid various network failures, eliminating the need for a centralized monitoring control unit that was previously required. be able to. Therefore, there is no need for a control line provided separately from the transmission path to each signal relay section, which has the effect of simplifying the configuration of the loop network.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of a loop network targeted by the present invention, Fig. 2 is a signal relay state diagram showing the operation of the control node switching means and the first connection control means, and Fig. 3 is a communication node The second part of the signal relay section
Figure 4 is a transmission line state transition diagram when the loop network is normal, and Figure 5 is a transmission line state transition diagram when a one-line transmission line failure occurs. 6 is a transmission line state transition diagram when a failure occurs in both transmission lines, and FIG. 7 is a transmission line state transition diagram when a node failure occurs. DESCRIPTION OF SYMBOLS 1... Control node, 2-6... Communication node signal relay section, 7, 8... Annular transmission line, 9... Control signal generator.

[Claims]

1. A communication device installed on the input side of a computer that receives unidirectional and random serial synchronization data, which includes a serial synchronization communication control unit that controls reception of the serial synchronization data, and after analyzing the serial reception data,
When multiple data buffer sections are stored in fixed word length units and one data buffer section is full,
A data buffer control unit that switches to the other data buffer unit upon completion of reception when the reception timeout or the remaining data buffer capacity is less than the maximum received message length; 1. A unidirectional synchronous communication device comprising: a parallel data transfer control section that transfers data to a computer by DMA transfer with a header section containing a number of data.

Claims (1)

and a first connection control means for continuing the internal connection state when the communication node signal relay unit is in a state where the control signal is transmitted to the node side from the input terminal to which the control signal was previously input in the normal state. The control signal is sent to the output terminal corresponding to the input terminal to which the control signal was input first, and
When the control signal is input to either the first input terminal or the second input terminal, a state in which no control signal is input to the other input terminal continues even after the predetermined period has elapsed. In this case, one of the input terminals and the output terminal corresponding to the other input terminal are internally connected and the communication node signal relay section is set to a loopback state, and after the predetermined period has elapsed, one of the other If a control signal is input to the input terminal, the loopback state is canceled and one of the other input terminals is internally connected to the corresponding output terminal, and the control signal is input to one of the input terminals. If there is no signal sent from the node side to the corresponding output terminal and no control signal is input to the other input terminal, the output corresponding to either one input terminal and the other input terminal. Terminals are internally connected and the communication node signal relay section is set to a loopback state, and one of the input terminals is internally connected to its corresponding output terminal, and a control signal is sent to one of the input terminals. If there is an input but no signal is sent from the node side to the corresponding output terminal, and if a control signal is input to one of the other input terminals, the terminals of one of the input terminals and the corresponding output terminal and Either one of the other input terminals and the corresponding output terminal should be internally connected to each other and the signal relay section should be set to a bypass state, and if there is no control signal input to either input terminal, the A leap network failure automatic avoidance method characterized by comprising a second connection control means for returning to the state (bypass state in which input and output terminals are internally connected).