JPH0287847A - Information transmission equipment - Google Patents

Abstract

PURPOSE:To prevent the deterioration of the transmission efficiency caused by an invalid information frame by detecting a bit error of an information frame, and initializing a signal transmission line, when the number of times of arrival within the time determined in advance of the information frame from its transmission origin exceeds a prescribed value. CONSTITUTION:The title device is provided with an error detecting means 31 for detecting a bit error of an information frame on a signal transmission line, and a storage means 32 for storing transmission origin information of the information frame whose error is detected by said means 31. Also, said device is provided with a counting means 34 for counting the number of times of arrival, when an information frame containing the same transmission origin information as the transmission origin information stored in the storage means 32 arrives from the signal transmission line within the time determined in advance, and an initializing means 35 for initializing the signal transmission line, when the count value of said counting means 34 exceeds a value determined in advance. In such a case, the storage means, the counting means and the initializing means are placed in at least one node device 3 on the signal transmission line. In such a way, the deterioration of the transmission efficiency caused by an invalid information frame can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is applied to an information transmission device in which a plurality of node devices are arranged on a loop-shaped signal transmission path. In particular, the present invention relates to prevention of reduction in transmission efficiency due to invalid information frames.

[Conventional technology]

2. Description of the Related Art Conventionally, an information transmission device in which a plurality of node devices are connected through a loop-shaped signal transmission path has been known. A terminal device is connected to the node device via branch line side transmission, and communication between the terminal devices is possible via the node device and the signal transmission path.

In such an information transmission device, communication between node devices is performed using information frames circulating on a signal transmission path. To transmit information from one node device to another, an information frame received from the terminal device via the branch line side transmission path is sent to the signal transmission path. This information frame circulates through each node device and reaches the destination node device. At this time, each node device determines whether the signal is addressed to the terminal device connected to itself based on the destination information, and if it is not addressed to the terminal device connected to itself, it sends it out to the signal transmission path as is. When the information frame is addressed to a terminal device connected to the own device, the information frame is sent to the destination terminal device via the branch line side transmission path, and the information frame received from the signal transmission path is sent as is, or the information frame within the frame is A code indicating that the frame has been received is added to the frame check field and sent out again to the signal transmission path.

Each node device further reads the transmission source information within the information frame and determines whether or not the information frame is transmitted by itself. If it is an information frame that it has transmitted, it sets the information frame to an empty state and sends it out to the signal transmission path.

As a result, when the information frame passes through the signal transmission path and reaches the source node device, the information frame is removed from the signal transmission path.

[Problem that the invention seeks to solve]

Here, while the information frame circulates through each node device,
The information frame may change in quality for some reason. In such a case, if the information frame is completely altered, it is necessary to take measures such as reinitializing the entire information transmission device. However, if there are only a few errors, for example bits, the errors can be detected and corrected using a frame check code.

However, if an error occurs in the source information in the information frame, no node device will determine that the information frame was sent by itself, so the invalid information frame will continue to circulate between node devices. Therefore, the transmission efficiency is effectively reduced. Furthermore, in extreme cases, all information frames on the signal transmission path may become invalid information frames, making communication between terminal devices impossible. Such invalid information frames cannot be removed by individual node devices, and the entire information transmission device must be reinitialized.

In order to solve these problems, it has been proposed to perform a forced reset when the communication waiting time is long, but this poses a major problem in terms of maintenance and management of the device.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide an information transmission device that can efficiently utilize a signal transmission path.

[Means for solving problems]

The information transmission apparatus of the present invention includes an error detection means for detecting bit errors in an information frame on a signal transmission path, a storage means for storing source information of an information frame in which an error is detected by the error detection means, and a storage means for storing transmission source information of an information frame in which an error is detected by the error detection means. A counting means for counting the number of times an information frame containing the same source information as the stored source information arrives from the signal transmission path within a predetermined time, and a count value of the counting means. The present invention is characterized by comprising initialization means for initializing the signal transmission path when the value exceeds a predetermined value.

The storage means, the counting means, and the initialization means are arranged in at least one node device on the signal transmission path. The error detection means may be arranged in the same node device in which each of the above-mentioned means is arranged, or may be arranged in a different node device.

Further, it is also possible to provide a relay monitoring device on the signal transmission path separately from the node device, and to arrange a storage means, a counting means, an initialization means, and an error detection means in this relay monitoring device. This relay monitoring device is also a node device in a broad sense, but in this specification, the term "node device" refers to a device that can serve as a source or destination for a signal transmission path.

[For production]

The transmission source information of the information frame in which the error has occurred is stored, and the number of times an information frame containing the same transmission source information arrives from the signal transmission path is counted. If there is no error in the source information, the information frame is removed from the signal transmission path using the source information.

On the other hand, an information frame that contains an error and arrives many times has an error in its source information. Therefore, when an information frame containing an error and having the same source information arrives a predetermined number of times within a predetermined time, the signal transmission path is initialized. This results in
It is possible to prevent a decrease in the transmission efficiency of the signal transmission path.

〔Example〕

FIG. 1 is a block diagram of an information transmission apparatus according to a first embodiment of the present invention.

The device of this embodiment includes a loop-shaped signal transmission path 1 and a plurality of node devices 2.3 arranged on this signal transmission path 1. Each of the node devices 2.3 has a means for sending an information frame containing source information to the signal transmission path 1, and a means for transmitting the information frame when the information frame sent by itself circulates around the signal transmission path 1 and returns. and means for removing the signal from the signal transmission path 1. The node device 3 further includes error detection means for detecting bit errors in information frames on the signal transmission path 1, storage means for storing source information of information frames in which errors have been detected by this means, and this storage means. a counting means for counting the number of times an information frame containing the same transmission source information as the transmission source information stored in the signal transmission line 1 arrives from the signal transmission path 1 within a predetermined time;
and initializing means for initializing the signal transmission path 1 when the count value of the counting means exceeds a predetermined value.

A branch transmission line 4 is connected to each node device 2.3. A terminal device 5 is connected to the branch line side transmission line 4 .

FIG. 2 shows the format of an information frame circulating on the signal transmission path 1.

This information frame includes an information frame header 101, a destination information field 102, and a source information field 103.
, an information field 104, and a frame check field 105.

FIG. 3 is a block diagram showing details of the node device 2. As shown in FIG.

This node device 2 is equipped with a signal transmitter 824 as a means for transmitting an information frame containing source information to the signal transmission path 1, and transmits the information when the information frame sent by itself circulates around the signal transmission path and returns. As means for removing frames from the signal transmission path 1, the relay control section 22 includes a transmission source determination section 29 and a selection circuit 30.

To explain in more detail, the node device 2 includes a signal receiving section 21, a relay control section 22, and a branch line side transmitting/receiving section 23 in addition to the signal transmitting section 24. The relay control unit 22 includes a transmission destination determination unit 25, a transmission buffer 26, a transmission source information storage unit 27, and a reception buffer 28 in addition to a transmission source determination unit 29 and a selection circuit 30.

The signal receiving unit 21 receives information frames from the signal transmission path 1. The relay control unit 22 extracts information from the signal transmission line 1 or the branch line side transmission line 4, and transmits the signal to the branch line side transmission line 4 via the branch line side transmission/reception unit 23 or via the signal transmission unit 24. Relay to Route 1.

The signal transmitter 24 transmits the information frame supplied from the relay controller 22 to the signal transmission path 1.

The destination determining unit 25 reads the destination information field 102 in the received information frame and determines whether the destination is a terminal device connected to the device itself. When the transmission destination is not a terminal device connected to the own device, the information frame is sent to the transmission source determination unit 29.

When the transmission destination is a terminal device connected to the own device, the information frame is stored in the transmission buffer 26, and the same information frame is either left unchanged or a code indicating that it has been received is added to, for example, a frame check field within the frame. Then, it is sent to the transmission source determination unit 29.

The transmission buffer 26 absorbs the difference between the transmission speed of the signal transmission line 1 and the transmission speed of the branch line side transmission line 4, and
Supply to 3.

The transmission source determination unit 29 reads the transmission source information field 103 of the received information frame, compares it with the information stored in the transmission source information storage unit 27, and determines whether or not the transmission source for the signal transmission path ■ is the own node device. judge. When the transmission source is not the own node device, the selection circuit 30 is controlled to supply the received information frame to the signal transmission section 24 as it is. When the transmission source is the own node device, the selection circuit 30 is controlled to supply the information frame output from the reception buffer 28 to the signal transmission section 24.

The reception buffer 28 stores the information frames received by the branch line side transmission/reception unit 23 from the terminal device, adjusts the speed, and also sends the stored information frames to the signal when there is an empty information frame on the signal transmission path 1. It is sent to the transmitter 24. When no information frame to be sent is stored in the receiving buffer 28, the receiving buffer 28 sends out an empty information frame.

The source information storage unit 27 reads the source information from the information frame output from the reception buffer 28 and extracts enough information to be able to determine that the source for the signal transmission path 1 is the own node device. and save it.

Through the above operations, the information frame is sent from the source node device to the destination node device, and when the information frame goes around the signal transmission path and reaches the source node device, the information frame is transferred to the destination node device. removed from the road;
A new information frame or an empty information frame is output to the signal transmission path 1.

FIG. 4 is a block diagram showing details of the node device 3. As shown in FIG.

Like the node device 2, this node device 3 includes a signal receiving section 21, a relay control section 22', a branch line side transmitting/receiving section 23, and a signal transmitting section 24. The relay control section 22' includes a transmission destination determination section 25, a transmission buffer 26, and a transmission source information storage section 27.
, a reception buffer 28, a source determination section 29, and a selection circuit 30. The operations of these circuits are similar to those of the node device 2.

The relay control unit 22' further includes an error detection unit 31 that detects bit errors in information frames on the signal transmission path 1, and a transmission source that stores source information of information frames in which errors are detected by the error detection unit 31. The information storage unit 32 determines when an information frame containing the same source information as the source information stored in the source information storage unit 32 arrives from the signal transmission path 1 within a predetermined time. It includes a counter 34 that counts the number of times, and a signal transmission path initialization section 35 and a selection circuit 36 that initialize the signal transmission path 1 when the count value of the counter 34 exceeds a predetermined value, Furthermore, a timer 37 is provided.

More specifically, the error detection section 31 compares the contents of the received information frame with the contents of the frame check field 105, and performs error detection including the source information field 103. The source information storage unit 32 determines whether or not the content of the source information field 103 of the information frame in which the error detection unit 31 has detected an error remains unchanged, or whether the received information frame has passed through the signal transmission path I. To the extent possible, for example, if the sender information field 103 contains check pits or other additional bits, information excluding them is extracted and stored. The source information determination unit 33 determines the source information field 10 of the information frame in which an error has been detected.
It is determined whether the sender information included in No. 3 matches the content stored in the sender information storage section 32, and if they match, the count value of the counter 34 is incremented. When the count value of the counter 34 exceeds a specified value, the signal transmission path initialization unit 35 controls the selection circuit 36 to set all information frames on the signal transmission path 1 to an empty state and disable this signal. Transmission line 1
Initialize. When an information frame having the same source information as the source information stored in the source information storage section 32 does not arrive within a preset time, the timer 37 stores the corresponding storage contents and count of the source information storage section 32. The value of the container 34 is deleted.

FIG. 5 is a block diagram of an information transmission apparatus according to a second embodiment of the present invention.

In this embodiment, a relay monitoring device 6 is provided on the signal transmission path 1 separately from the node device 2 that is the source or destination of the information frame, and this relay monitoring device 6 detects errors in the information frame and detects invalid information. This is to remove frames.

FIG. 6 is a block diagram of the relay monitoring device 6. As shown in FIG.

This relay monitoring device 6 is the same as the node device 3 in the first embodiment, except that the communication function with the terminal device is removed. That is, the signal receiving section 21, the relay control section 22'',
and a signal transmitter 24. The relay control unit 22″ includes an error detection unit 31 that detects bit errors in information frames on the signal transmission path 1, and a source information storage unit that stores source information of information frames in which errors are detected by the error detection unit 31. The storage unit 32 and the number of arrivals when an information frame containing the same source information as the source information stored in the source information storage unit 32 arrives from the signal transmission path 1 within a predetermined time. a counter 34 for counting, and a signal transmission path initialization section 35 and a selection circuit 36 that initialize the signal transmission path 1 when the count value of the counter 34 exceeds a predetermined value; A timer 37 is provided.

The operation of each of these parts is the same as that of each part with the same reference numeral in the node device shown in FIG.

In the above embodiment, an example was shown in which the storage means, the counting means, and the initialization means are arranged in one node device or relay monitoring device. However, it is also possible to arrange the error detection means in another node device and add error information to the frame check field of the information frame when an error is detected. In this case, a node device or relay monitoring device equipped with storage means, counting means, and initialization means can determine that there is an error in the information frame simply by referring to the frame check field.

Furthermore, the present invention can be implemented in the same manner even if a plurality of node devices or relay monitoring devices provided with counting means and initialization means are arranged on a signal transmission path.

The present invention can be implemented in the same manner by using methods other than those used in the above-described embodiments as a method for initializing the signal transmission path. For example, the signal transmission path may be initialized by forcibly transmitting a claim token defined in the token ring system to the signal transmission path.

〔Effect of the invention〕

As described above, the information transmission device of the present invention can quickly change the signal transmission path when an error-prone information frame, especially an information frame with an error in the source information, is circulating on the signal transmission path. Can be initialized. This can prevent invalid information frames from continuing to circulate forever and, in the worst case, filling up the signal transmission path, thereby preventing communication between terminal devices from becoming impossible.

Therefore, the present invention has the effect of preventing a reduction in transmission efficiency due to invalid information frames.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an information transmission device according to a first embodiment of the present invention. FIG. 2 is a diagram showing the format of an information frame. FIG. 3 is a block diagram of the node device. FIG. 4 is a block diagram of the node device. FIG. 5 is a block diagram of an information transmission device according to a second embodiment of the present invention. FIG. 6 is a block diagram of the relay monitoring device. ■... Signal transmission path, 2.3... Node device, 4...
- Branch line side transmission line, 5... Terminal device, 6... Relay monitoring device, 21... Signal receiving section, 22.22', 22''.
... Relay control unit, 23... Branch line side transmitting and receiving unit, 24...
- Signal transmitter, 25... Destination determination unit, 26... Transmission buffer, 27.32... Source information storage unit, 28
. . . reception buffer, 29 . . . source determination unit, 30.
36... Selection circuit, 31... Error detection unit, 33...
- Source information determination unit, 34...Counter, 35...Signal transmission path initialization unit, 37...Timer.

Claims (1)

[Claims] 1. A loop-shaped signal transmission path and a plurality of node devices disposed on the signal transmission path, each of the plurality of node devices transmitting an information frame containing source information to the signal. An information transmission device comprising means for transmitting the information frame to a transmission path, and means for removing the information frame from the signal transmission path when the transmitted information frame circulates around the signal transmission path and returns. error detection means for detecting bit errors in information frames on a transmission path; storage means for storing source information of information frames in which errors have been detected by this means; a counting means for counting the number of times an information frame containing source information arrives from the signal transmission path within a predetermined time period; An information transmission device characterized by comprising: initialization means that sometimes initializes the signal transmission path.