JPH07250063A - Monitor circuit restoring method - Google Patents

Abstract

PURPOSE:To issue the reset forms to all communication equipments by a 1st transmitter device by sending a reset frame issue request signal to the 1st communication equipment in order to update the latest transmission time written into the time control table of each communication equipment. CONSTITUTION:A monitor device 10 monitors each transmitter device and sends a reset frame transmission command to a communication equipment 1 when a communication equipment having no answer is detected. Then another reset frame transmission command is generated and sent to the communication equipment having no answer. The equipment 1 or the communication equipment having no answer that received the reset frame transmission command from the device 10 transmits a reset frame. The communication equipment which received the reset frame reads the latest transmission time out of the reset frame and updates the time of the transmitter communication equipment written into a time control table.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monitoring apparatus for sequentially monitoring the status of each communication apparatus by polling, and the monitoring apparatus is connected to a first communication apparatus. The present invention relates to a method for recovering a monitoring line of a communication network connected by, especially a communication network connected so as to have a plurality of routes.

A monitoring device for sequentially monitoring the state of each communication device by polling is connected to the first communication device, and the first communication device is connected to the first communication device.
A plurality of communication devices are connected to the communication device of No. 1 through a transmission line, and as a communication network for polling communication devices other than the first communication device starting from the first communication device, for example, As shown in FIG. 5A, communication devices are connected in a tree shape, and as shown in FIG. 5B, connected in a loop shape or a mesh shape (not shown).

Since the same polling signal is not input to one communication device via a plurality of communication devices in the tree-shaped connection, each communication device receives the polling signals in the input order. Since it suffices to do so, there is no need to perform processing such as discarding the polling signal input later, but in the loop / mesh network, the same polling signal may be input from multiple communication devices,
It becomes necessary to perform control such as discarding the polling signal input later.

Since the present invention is applied to network monitoring in the case where a communication device is connected in a loop or mesh (not shown) and has a plurality of routes, the following description will be given with reference to FIG.
The loop network shown in (B) will be described as an example.

[0005]

2. Description of the Related Art FIG. 5 is a block diagram of an example communication network, FIG. 6 is a diagram showing an example signal format and time management table, and FIG. 7 is a polling example of FIG. FIG. 8 is a diagram showing a procedure, and FIG. 8 is a diagram showing a state in which there is no response in FIG. 5B as an example.

In the communication network shown in FIG. 5 (B),
A monitoring device 10 that sequentially monitors the status of each of the communication devices 1 to 4 by polling is connected to the communication device 1.
2, 3 and 4 are connected by a transmission path so as to have a loop path.

Each of the communication devices 1 to 4 broadcasts commands and responses other than addressed to the own communication device to all communication devices connected to the own communication device. As shown in FIG. 6A, the command format has a source communication device address area, a destination communication device address area, a command transmission time area, and a command section for writing the contents of the command.
Commands are sent in this format.

As shown in FIG. 6B, the response format has a source communication device address area, a destination communication device address area, a response transmission time area, and a response section for writing the contents of the response, and the response is in this format. To send.

In the case of the communication network of FIG. 5 (B),
When the monitoring device 10 obtains the status of the communication device 1 by polling, the monitoring device 10 is written in the source communication device address area of the command format shown in FIG. 6A and the communication device is written in the destination communication device address area. 1 is written, the current time is written in the command transmission time area, the transmission of the status information is written and transmitted in the command part, and the response from the communication device 1 is the source communication in the response format of FIG. 6B. The communication device 1 is written in the device address region, the monitoring device 10 is written in the destination communication device address region, the current time is written in the response transmission time region, and the state information is written and transmitted in the response part.

When the status of the communication devices 2 to 4 is obtained from the monitoring device 10 by polling, the communication device 1 is used as a starting point, and the monitoring device 10 is set in the source communication device address area of the command format shown in FIG. 6A. Write, write the communication device 2 or 3 or 4 in the destination communication device address area,
The current time to be transmitted from the communication device 1 is written in the command transmission time area, the transmission of status information is written and transmitted in the command part, and the response from the communication devices 2 to 4 is as shown in FIG.
In the response format of (B), the communication device 2 or 3 or 4 is written in the transmission source communication device address area, the monitoring device 10 is written in the reception destination communication device address area, and the current time is set in the response transmission time area. Write and send status information in the response section.

The communication device 1 receiving this response,
Notify the monitoring device 10 of the content of the response. Each of the communication devices 1 to 4 has a time management table as shown in FIG. 6D. In the time management table, an area in which the latest transmission time of the communication device itself is written and, for example, in the case of the communication device 1, other The latest transmission time of the communication devices 2 to 4 of the other communication device is written, and when the same signal is input a plurality of times, the signal with the latest transmission time is first received and the communication device of the corresponding communication device receives the signal. By writing the latest transmission time in the latest transmission time area and referring to the time management table thereafter, when the same signal is received, this is rejected.

Here, the monitoring device 10 includes the communication devices 1 to 4.
When polling is performed on the communication device 3, the communication device 3 receives the same command from the communication devices 2 and 4 and
Even if the same command is received from the communication devices 1 and 3,
For convenience of description, a case where the communication device 3 receives the same command will be described below. When issuing the command,
When issuing a response, the contents shown in the command format and the response format shown in FIGS. 6A and 6B are written and transmitted, but the description is omitted because it is complicated.

When the monitoring device 10 shows the procedure of polling the communication devices 1 to 4, as shown in FIG. 7, a command is issued to the communication device 1, a response is received, and then the communication device 1 is activated. A command is issued to the communication device 2 as a starting point, a response is received via the communication device 1, and then a command is issued to the communication device 3 starting from the communication device 1, but the transmission time is September 10, 1993. 11:15 pm
If it is minutes, this time is written in the command transmission time area of the command format, the communication device 3 is written in the destination communication device address area, and the communication devices 2, 4
To be broadcast to.

If a command from the communication device 2 arrives at the communication device 3 first, the latest transmission time area of the communication device 1 in the time management table of the communication device 3 is 1993.
Write 11:15 on September 10, and return a response to the monitoring device 10.

Next, when the same command is sent from the communication device 4, it refers to the time management table, recognizes that this command has already been received, and discards this command. Next, a command is issued to the communication device 4 starting from the communication device 1 and a response is received via the communication device 1.

Here, when transmitting signals, each of the communication devices 1 to 4 writes the latest transmission time in the latest transmission time area of the time management table and issues a signal at a time older than the latest transmission time. Then, since any of these is wrong, a reset frame as shown in FIG. 6C is transmitted.

The format of this reset frame is
It has a source communication device address area, an address of all communication devices other than the transmission source (actually written as oxff), a transmission time area, and a time update area for writing a time update. When the communication device 1 writes the current time in the transmission time area and transmits it to 2 to 4 of all communication devices, the communication devices 2 to 4 set the latest transmission time of the communication device 1 in the time management table to the current time. Will be updated.

Then, when the signal is transmitted with the current time as the transmission time, each communication device receives the signal normally.

[0019]

However, as shown in FIG.
As shown in (A), the transmission time of the command from the communication device 1 to the communication device 3 was 11:15 on September 10, 1993.
If the characters are garbled at 11:15 on the day, 20 in the latest transmission time area of the communication device 1 in the time management table of the communication device 3
11:15 on September 10, 2000 is written, and the response is transmitted to the monitoring device 10 with the current time as the transmission time.

The monitoring device 10 receives this response,
When the current time is 11:17 on September 10, 1993, when a command is sent to the communication device 3 via this time as the transmission time, the communication device 3
Then, although this command is normally received, the latest transmission time of the communication device 1 is 200 when referring to the time management table.
It is 11:15 on September 10, 0, and the received command is old and is discarded.

Since the monitoring device 10 is waiting for a response from the communication device 3 but does not return, it times out, the communication device 3 is treated as no response, and the monitoring line for the communication device 3 cannot be restored.

Further, as shown in FIG. 8B, 11:16 on September 10, 1993, the transmission time of the response from the communication device 3, is due to a transmission line failure or the like, and 11:01 on September 10, 2000.
If the character is garbled in 6 minutes, the communication device 1 displays the year 2000 9 in the latest transmission time area of the communication device 3 in the time management table.
Write 11:16 on the 10th of the month and send a response to the monitoring device 10 via the communication device 1.

Next, the current time is September 10, 1993.
When the date is 11:17, when the monitoring device 10 transmits a command to the communication device 3 via the communication device 1 with this time as the transmission time, the communication device 3 normally receives the command, In the latest transmission time area of the communication device 1 of the time management table, 11:01 on September 10, 1993.
7 minutes is written, and the response whose transmission time is 11:18 on September 10, 1993 is sent to the monitoring device 1 via the communication device 1.
Send to 0.

In the communication device 1, referring to the time management table, the latest transmission time of the communication device 3 is September 1, 2000.
Since it is 11:16 on the 0th and is old, this response is discarded.

Since the monitoring device 10 is waiting for a response from the communication device 3 but does not return, it times out, the communication device 3 is treated as no response, and the monitoring line for the communication device 3 cannot be restored.

That is, if the signal received by the communication device is shifted in the direction in which the transmission time of the partner communication device is advanced, there is a problem that the monitoring line from the monitoring device is disconnected. It is an object of the present invention to provide a monitoring line restoration method that can restore a monitoring line even when the transmission time of a communication device on the opposite side is advanced with respect to a signal received by the communication device.

[0027]

FIG. 1 is a diagram showing a supervisory line restoration procedure of the present invention. As shown in FIG. 1, the first is a monitoring device that sequentially monitors the status of each communication device by polling.
To the first communication device, a plurality of communication devices are connected to the first communication device by a transmission line, and polling of communication devices other than the first communication device is performed by the first communication device. Performed with the transmission time at the first communication device as the starting point, and each communication device outputs a reception signal not addressed to itself by a broadcast to a communication device connected to the own device by a transmission path, The signal addressed to the own device and the signal addressed to the monitoring device in the first communication device are managed by writing the latest transmission time in the time management table for each source communication device, and managing the time when the signal is received. In the communication network that compares the time written in the table, discards a signal that is not new, and sends a response signal with a transmission time when responding, in the monitoring device, a communication device determines that there is no response The monitoring device is A reset frame issuance request signal with a transmission time for updating the latest transmission time written in the time management table of each communication device is transmitted to the device, and the first communication device sends an address to all communication devices. A reset frame is issued, then a reset frame issuance request signal is transmitted to the certain communication device that has not responded, and the certain communication device issues a reset frame addressed to all communication devices.

[0028]

According to the present invention, when a communication device becomes unresponsive, the monitoring device transmits the first communication device to update the latest transmission time written in the time management table of each communication device. A reset frame issuance request signal with a time is transmitted to cause the first communication device to issue a reset frame addressed to all communication devices.

Then, if the latest transmission time of the first communication device in the time management table of each communication device is incorrect, the time at which the reset frame is issued is reached, and hence the command from the monitoring device can be received thereafter. Like

Next, the monitoring device transmits a reset frame issuance request signal to the communication device which has become unresponsive through the first communication device to issue the reset frame. As a result, the latest transmission time of the communication device that has not responded in the time management table of each communication device becomes the time when this reset frame was issued, and thereafter, normal polling can be performed.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 is a diagram showing a supervisory line restoration procedure according to an embodiment of the present invention, and FIGS. 3 and 4 are diagrams showing a flow of processes from a reset frame transmission instruction to a reset frame reception process (part 1). ) (Part 2).

As shown in FIG. 3A, the monitoring device 10 monitors each communication device. When a non-responsive communication device is detected, a reset frame transmission instruction command for the communication device 1 is generated, The generated command is transmitted to the communication device 1, then the reset frame transmission instruction command for the non-responsive communication device is generated, and the generated command is transmitted to the non-responsive communication device.

As shown in FIG. 3B, the communication device 1 or the non-responsive communication device that has received the reset frame transmission instruction command from the monitoring device 10, when receiving the command, checks whether the command is normal or abnormal, If it is abnormal, discard it,
In the case of normal operation, a reset frame as shown in FIG. 6C described above is generated and the generated reset frame is transmitted.

The communication device receiving the reset frame
As shown in FIG. 4C, it is checked whether the reset frame is normal or abnormal, and if it is abnormal, it is discarded. If it is normal, the address of the source communication device is recognized, the time is read from the received frame, and The time of the transmission source communication device in the time management table shown in D) is updated.

FIG. 2 is a diagram showing a monitoring line restoration procedure when the communication device 3 becomes unresponsive as shown in FIGS. 8 (A) and 8 (B). The cause of no response is that the transmission time of the command from the communication device 1 changes to a newer one as shown in FIG. 8 (A) and the response from the communication device 3 as shown in FIG. 8 (B). However, since the monitoring device 10 does not know which cause caused the communication device 3 to become unresponsive, the monitoring device 10 uses the communication device 1 as shown in FIG. 6 to request the issuance of the reset frame to the issuance of the reset frame, and then to the communication device 3 which has not responded, as shown in FIG.
The reset frame issuance request shown in (C) is issued.

Specifically, the communication device 1 sets all the communication devices 2, 3, with the transmission time of the reset frame format shown in FIG. 6 (C) as the current time, which is 11:20 on September 10, 1993. 4 and sends the latest transmission time of the communication device 1 in the time management table of the communication devices 2, 3 and 4 to 19
It is 11:20 on September 10, 1993.

As a result, if the latest transmission time of the communication device 1 in the communication device 3 is incorrect, it is corrected correctly,
After that, the command from the monitoring device 10 can be received via the communication device 1.

Therefore, when the monitoring device 10 issues a reset frame issuance request to the communication device 3 via the communication device 1,
This command is correctly received, and the communication device 3 receives the command shown in FIG.
In the reset frame format shown in (C), the transmission time is set to 11:21 on September 10, 1993, which is the current time, and the transmission is performed to all the communication devices 1, 2, 4 and the communication devices 1, 2, 4 It is assumed that the latest transmission time of the communication device 3 in the time management table is 11:21 on September 10, 1993.

As described above, since the contents of the time management table of each of the communication devices 1 to 4 become normal, the monitoring line from the monitoring device 10 to the communication device 3 becomes normal, and normal polling can be performed thereafter. I can.

[0040]

As described in detail above, according to the present invention, there is an effect that the monitoring line can be restored even if the transmission time of the partner communication device advances in response to the signal received by the communication device.

[Brief description of drawings]

FIG. 1 is a diagram showing a supervisory line restoration procedure of the present invention,

FIG. 2 is a diagram showing a supervisory line restoration procedure according to an embodiment of the present invention,

FIG. 3 is a diagram showing a process flow from a reset frame transmission instruction to a reset frame reception process (No. 1),

FIG. 4 is a diagram showing a process flow from a reset frame transmission instruction to a reset frame reception process (No. 2),

FIG. 5 is a block diagram of an example communication network,

FIG. 6 is a diagram showing a format of each signal and a time management table of one example;

FIG. 7 is a diagram showing a polling procedure in the case of FIG. 5B as an example,

FIG. 8 is a diagram showing a non-responsive state in FIG. 5B as an example.

[Explanation of symbols]

 1 to 9 are communication devices, and 10 is a monitoring device.

Claims (1)

[Claims] 1. A monitoring device for sequentially monitoring the status of each communication device by polling is connected to a first communication device, and a plurality of communication devices are connected to the first communication device by a transmission line. , The polling to the communication devices other than the first communication device is performed with the transmission time at the first communication device as a starting point, and each communication device receives the data not addressed to itself. The signal is output to the communication device connected to the own device through a transmission line, and the signal addressed to the own device and the signal addressed to the monitoring device in the first communication device are transmitted by the latest transmission for each source communication device. The time is written and managed in the time management table, and when the signal is received, it is compared with the time written in the time management table, and the signal that is not new is discarded, and if it responds, the response signal is transmitted with the transmission time added. The communication network In the visual device, when a certain communication device determines that there is no response, the monitoring device sets the transmission time for causing the first communication device to update the latest transmission time written in the time management table of each communication device. A reset frame issuance request signal is transmitted, the first communication device issues a reset frame addressed to all communication devices, and then the non-responsive communication device issues a reset frame issuance request signal. Is transmitted, and the certain communication device is made to issue a reset frame addressed to all the communication devices.