JPH0447827A - Abnormal data communicating preventing system for loop network - Google Patents

Abstract

PURPOSE:To prevent an abnormal data from flowing to a terminal by stopping transmitting a data received from a channel to the terminal by each node executing fully duplex communication in the case of generating abnormality in the node connected to the terminal as a communicating party. CONSTITUTION:Assuming that a node 1d on a terminal A side breaks down, a monitoring cycle is not t1 for a bit monitoring part 65 for monitoring a node 1b on a terminal B side. Assuming that the bit monitoring part 65 for monitor turns the output to '1'. Consequently, the output to the terminal B at a reception part 64 of the node 1b is turned to a Mark state ('1' at all times), and the transmission of the data received from the channel to the terminal B is stopped. Thus, at the terminal B, the data transmitted by the terminal itself is not returned as it is. Similarly, even when the abnormality is generated at the node 1b, the output is turned to '1' and the output to the terminal A is turned to the Mark state. Therefore, for the terminal A, the data transmitted by the terminal itself is not returned as it is.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a loop network, and particularly to a method for preventing abnormal data communication in a loop network that enables transparent transmission.

[Prior Art] Time-division multiplexed loop networks, typified by circuit-switched loop networks, are widely used due to their ability to perform transparent transmission.

FIG. 3 shows an example of the configuration of a time division multiplexed loop network, and FIG. 4 shows its frame configuration.

A time division multiplexed loop network consists of frames of a fixed length circulating on a loop transmission path.
Transmission between each terminal is performed by exclusively allocating a certain channel within the frame.

For example, in FIG. 3, when communicating between terminal A and terminal B, channel 22 is allocated within frame 21.

Here, a method is being considered in which full-duplex communication between terminal A and terminal B is performed using only one channel.

FIG. 5 shows a method for performing full-duplex communication using only one channel.

First, node 1b sends data from terminal B to channel 2.
2 and send it to node 1d.

Next, within the node, a slight delay is set between the timing of reading the channel and the timing of writing to the channel, and node 1d reads the contents of channel 22 sent from node lb, sends it to terminal A, and then ,
This time, write the data from terminal A to channel 22,
Send to node 1b. By performing similar transmission/reception operations on the channel at node 1b, a total of 21 communications between terminals A and B can be realized using only one channel. This transmission is transparent, meaning the loop network is not aware of what data is flowing within the channel.

Suppose now that an abnormality occurs in the node 1d connected to terminal A. The abnormality may include a power outage of the node 1d. Normally, such a loop network duplicates the loop transmission path and performs loopback, so that when one node goes down, the entire system does not go down.

However, if the node 1d goes down, the data written and sent from the terminal B to the channel 22 will be returned as is without being changed to the data from the terminal A on the way. In other words, terminal B will receive the data it sent as is, which may cause the terminal to malfunction.

As a method for solving this problem, a method as shown in FIG. 6 was considered. Now, if node la is the node that monitors the entire loop, node 1a recognizes that node 1d is down by periodically referring to the status of each node (Fig. 6 ■), and then node 1a The node 1d notifies the node 1b that the node 1d is down (Fig. 6 (■)) Upon receiving this, the node 1d stops receiving data (Fig. 6 (■)).

[Problem to be Solved by the Invention] However, in the case of the method shown in FIG. 6, each of the above steps ■■■ is performed by software control inside the node. During this time, abnormal data flows to terminal B (the data sent by itself is returned unchanged).

An object of the present invention is to eliminate the above-mentioned drawbacks of the conventional technology in a loop network, so that when an abnormality occurs in one node performing full-duplex communication, the other node quickly detects the abnormality and An object of the present invention is to provide a new abnormal data communication prevention method that can prevent abnormal data transmission to (data sent by oneself is returned unchanged).

[Means for Solving the Problems] The abnormal data communication prevention method of the present invention has a configuration in which a frame of a certain length circulates on a loop transmission path, and transmission between each terminal uses a channel within the frame. A loop network that performs transparent communication,
When performing full-duplex communication between terminals A and B, after receiving terminal B's data from terminal A or the channel, transmit the data to terminal B using the same channel, and perform the same operation on terminal B. By doing this, a total of 21 connections between terminals in one channel! In a loop network that enables communication, a 1-pit area for monitoring is provided in the channel in addition to the area for data transmission, and terminal A side has t for that bit.
A signal that turns ON and OFF at a period of l is transmitted, and the terminal B side transmits a signal that turns ON and OFF at a period of tl that is different from tl, and on each terminal side, when receiving, the bit signal turns ON and 0FFI at a normal period. , and if an abnormality is detected, it stops sending the received data from the channel to the terminal.

[Operation] A 1-bit area for monitoring is provided in the channel for terminal communication, and the two nodes to which terminals A and B are connected, which are performing full-duplex communication, each have a period of occurrence for that bit. t1. A signal that turns ON and OFF is transmitted at t2, and the normality of the cycle is checked upon reception. When either one of the two nodes goes down, an abnormality in the period t1 or t2 is detected in the other node. Since the partner node stops sending the received data from the channel to the terminal, it is possible to prevent an abnormal situation in which its own data returns to terminal A or terminal B.

[Example code] Embodiments of the present invention will be described below with reference to the drawings.

First, as shown in FIG. 1, within the channel 22 allocated within the transmission frame, the data transmission area 23 is
In addition, a 1-bit area 24 for monitoring is provided.

Next, as shown in FIG. 2, a transmitting/receiving section within the node is configured. That is, the transmitting section 61 in the node is provided with a monitoring bit transmitting section 62 in addition to the data transmitting section 63, and the receiving section 64 in the node is also provided with a monitoring bit monitoring section 65 in addition to the data receiving section 66. Provide another.

The monitoring bit transmitting unit 62 in the transmitting unit 61 transmits the monitoring bit 2 in the channel 22 while transmitting data.
4, it has a function of transmitting a signal that repeats ON and OFF at regular intervals. Further, the transmission cycle can be set in two ways, a cycle t1 and a cycle t2 (≠t1), by a selection signal sent to the monitoring bit transmitter 62.

On the other hand, the monitoring bit monitoring unit 65 in the receiving unit 64 receives the signal transmitted from the monitoring bit transmitting unit 62, and changes the contents of the received monitoring bit 24 to ON and OFF at regular intervals.
While repeating, the output is set to "0", and when the synchronization deviates from its own monitoring cycle, the output is set to "1". Similarly to the transmission cycle, the monitoring cycle can be set in two ways, ie, cycle t11 and cycle t2, by a selection signal sent to the monitoring bit monitoring section 65.

Next, the operation will be described using as an example the case where full duplex transmission is performed between terminals A and B in FIG.

In the case of communication between terminal A and terminal B, for example, terminal ArpJ
The node 1d on the terminal B side sets the transmission period to tl and the monitoring period to t2, and the node 1b on the terminal B side sets the transmission period to tl and the monitoring period to t2.
Contrary to d, the transmission period is set to t2. The monitoring cycle is set to tl.

'iH During constant communication, the same signal as the set monitoring cycle is input to the monitoring bit monitoring section 65 in the receiving section 64 of each node, so its output is "0". Also, in the data receiving section 66, the received data is sent to the terminal at that time.

That is, in the node 1b to which terminal B belongs, the receiving unit 64
The signal input to the monitoring bit monitoring unit 65 in the node 1d is the signal from the monitoring bit transmitting unit 62 of the node 1d, and since this has the same cycle as the monitoring cycle t2 set in the node 1d, the monitoring bit monitoring unit 65 in The output of the bit monitoring unit 65 becomes "0". Further, the signal received by the data receiving unit 66 of the node 1d is data set at the transmission period t1 in the node 1d and transmitted from the data transmitting unit 63, and this terminal A
Data from the side is sent to terminal B as is.

On the other hand, in the node 1d to which terminal A belongs, similarly,
The same signal as the monitoring cycle t1 set in the node 1b is input to the monitoring bit monitoring unit 65, and its output is "0".
In addition, in the data receiving section 66, node 1
At step b, data from the data transmitter 63 set at the transmission cycle t2 is received and sent to terminal A as is.

However, if the node 1d on the terminal A side is now down, the monitoring bit monitoring unit 65 of the node 1b on the terminal BFj
The monitoring cycle is no longer tl. Therefore, the monitoring bit monitoring unit 65 sets its output to "1". As a result node 1
The output from the receiving unit 64 of B to terminal B is M a r
k state (always "1"), which results in stopping sending the received data from the channel to terminal B. This prevents terminal B from returning the data it sent as is.

Since the above control is performed by hardware, node 1
Immediately after an abnormality occurs in d, the output to terminal B can be brought into the Mark state.

Similarly, if an abnormality occurs in node 1b, node 1d
Since the monitoring cycle of the monitoring bit monitoring unit 65 is no longer t2, its output is set to "1", and the output to terminal A is set to M.
Set to ark state. Therefore, as in the case of terminal B when the node 1d goes down, terminal A will no longer receive the data it sent back unchanged.

[Effects of the Invention] As explained above, according to the present invention, each node to which a terminal performing full-duplex communication is connected can detect an abnormality in the node to which the communication partner terminal is connected. If this occurs, the flow of abnormal data to the terminal can be prevented by quickly detecting this and stopping sending the received data from the channel to the terminal. the result,
A highly reliable system can be provided.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a transmission frame within a channel according to an embodiment of the present invention, FIG. 2 is a diagram showing the configuration of a transmitting/receiving section within a node according to an embodiment of the present invention, and FIG. 3 is a diagram showing a general Figure 4 is a diagram of the frame configuration of a time division multiplexed loop network. Figure 5 is a diagram of the frame configuration of the time division multiplexed loop network.
The figure shows a state in which full-duplex communication is performed using only one channel, and FIG. 6 is a diagram showing the control procedure of the abnormal data prevention method when a node is down in the conventional method. In the figure, 1a to lb are nodes, 12 is a loop transmission path, and 21
is a transmission frame, 22 is a communication channel between terminals A and B,
23 is a data transmission area, 24 is a 1-bit area for monitoring, 61 is a node transmitting section, 62 is a monitoring bit transmitting section, 63 is a data transmitting section, 64 is a node receiving section, 65 is a monitoring bit The monitoring section 66 indicates a data receiving section. Figure Figure

Claims (1)

[Claims] 1. It is a loop network in which a frame of a certain length circulates on a loop transmission path, and transmission between each terminal is performed using channels within the frame for transparent communication. When performing full-duplex communication between terminals B, after receiving terminal B's data from terminal A or the channel, transmit the data to terminal B using the same channel, and perform the same operation on terminal B. ,1
In a loop network that enables full-duplex communication between terminals over a channel, a 1-bit area for monitoring is provided in the channel in addition to the area for data transmission, and terminal A side turns on that bit at a cycle of t1. , transmits a signal to turn off, and on the terminal B side, turns on at a period of t2, which is different from t1.
, a signal that turns OFF is transmitted, and each terminal always monitors whether the bit signal is turned ON and OFF at a normal cycle during reception, and if an abnormality is detected, it stops sending the received data from the channel to the terminal. A method for preventing abnormal data communication in a loop network characterized by: