JP2000151668A - Monitor system for ring network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the ring network monitor system that can detect an erroneous frame fallen into a communication disable state regardless of a simple system configuration and can immediately restore the detected erroneous frame. SOLUTION: Each node N describes its own node address to a sender address description area and generates a communication frame where an information part corresponding to itself among passing bit information described in a passing bit information description area is rewritten to be already passing when itself is a sender of the communication frame, or generates the communication frame where the information part corresponding to itself among passing bit information described in the passing bit information description area is rewritten to be already passing when itself is not a sender of the communication frame and a result of decision by a passing bit confirmation section 19 indicates that the received communication frame bas not passed all of a plurality of nodes N under the regard that the received communication frame is a normal frame, and transmits the generated communication frame to a node toward downstream to itself.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ring type network for monitoring the communication state of a ring type network in which a plurality of nodes are connected to each other via a ring type transmission line so as to be able to exchange data with each other. The present invention relates to a monitoring system, and more particularly to a ring-type network monitoring system capable of detecting an abnormal frame in a communication disabled state and recovering the detected abnormal frame immediately with a simple system configuration.

[0002]

2. Description of the Related Art Conventionally, a ring network is generally known in which a plurality of nodes are connected to each other via a ring-type transmission path so that data can be exchanged therebetween.
Also, as a monitoring method for this ring network,
For example, as disclosed in Japanese Patent Application Laid-Open No. 3-145239, a token ring monitoring method including a counter unit capable of adding a value to a token frame is known.

[0003] The token ring monitoring method disclosed in the above publication includes a counter unit capable of adding a value to a token frame circulating on the token ring, while each node receives a frame from a preceding transmission line. Receiving means, transmitting means for transmitting a frame to a subsequent transmission path, counter holding means for holding a value of a counter portion in the passed token frame, and frame processing having a receiving frame processing function for processing a received frame Means.

According to the token ring monitoring method,
Each time the node receives the token frame, it holds the value of the counter in the received frame and adds “1” to the value of the counter. Also, when each node receives the token frame, it calculates the difference between the previous held value and the current held value, and determines whether the calculated difference value is equal to the total number of nodes in the token ring. I do. Here, if the communication functions of all nodes in the token ring are normal, the calculated difference value is equal to the total number of nodes, while the communication function of any node in the token ring is abnormal. In some cases, the obtained difference value is different from the total number of nodes.

Therefore, in each node, it is determined whether or not the communication function of all nodes in the token ring is normal by determining whether or not the obtained difference value is equal to the total number of nodes. be able to. If the communication function of any node in the token ring is determined to be abnormal as a result of the diagnosis, the communication function is determined to be abnormal by sequentially comparing the held values of mutually adjacent nodes. A certain failed node can be identified.

[0006]

However, the above-described conventional token ring monitoring method, for example, allows cyclic transmission of a communication frame in a single direction between a plurality of nodes and simultaneously transmits a plurality of communication frames. When the present invention is applied to a ring-type network configured by mutually connecting data via a ring-type transmission path allowing coexistence, a counter for each of a plurality of communication frames is provided for each node. Therefore, it is necessary to provide a memory for holding the value of and a frame control circuit, and therefore, the scale of the monitoring circuit provided for each node becomes large and the configuration of each monitoring circuit becomes complicated. The challenges were inherent.

Therefore, even when the present invention is applied to the ring network of the above-described embodiment, it is possible to detect, with a simple configuration, an abnormal frame that has fallen out of communication and immediately recover the detected abnormal frame. The development of a new technology has been awaited among those involved.

The present invention has been made in view of the above-mentioned circumstances, and allows cyclic transmission of a communication frame in a single direction between a plurality of nodes and allows a plurality of communication frames to coexist at the same time. Even when applied to a ring-type network that is configured to be connected to each other via a permissible ring-type transmission path so that data can be exchanged, a simple system configuration can be used to detect abnormal frames that have failed to communicate. Another object of the present invention is to provide a ring-type network monitoring system capable of immediately recovering a detected abnormal frame.

[0009]

In order to solve the above-mentioned problems, a first aspect of the present invention is directed to a ring configured by connecting a plurality of nodes to each other via a ring-type transmission path so as to be able to exchange data with each other. A ring network monitoring system for monitoring the communication state of a network, wherein the transmission path allows cyclic transmission of a communication frame in a single direction, and a plurality of communication frames coexist on the transmission path at the same time. The communication frame is configured to allow at least a source address description area in which a source address of a source node of the communication frame is described, and the communication frame passes through each of the plurality of nodes. For each time, of the passing bit information indicating the passing status of the communication frame of each of the plurality of nodes, the corresponding information location is rewritten under each node. Each of the plurality of nodes is configured to receive the communication frame from a node located on its upstream side, and a unique value is set for each of the plurality of nodes. Own node address storing means for storing the own node address; and, when a communication frame is received by the frame receiving means, referring to the description content in the received communication frame, the received communication frame is stored in the plurality of nodes. A frame discriminating means for discriminating whether an occupied frame transmitted from any node including itself or a non-occupied frame not transmitted from any of the plurality of nodes; When it is determined that the received communication frame is an occupation frame as a result of the frame determination by the frame Address comparing and judging means for judging whether or not the source address described in the communication frame described above matches the own node address stored in the own node address storing means, and comparison judgment by the address comparing and judging means As a result, when it is determined that the source address and the own node address do not match, by referring to the passing bit information described in the passing bit information description area in the received communication frame,
An all-node passing determination unit that determines whether the received communication frame has already passed the source of the plurality of all nodes, and a result of the determination by the all-node passing determination unit that the received communication frame is When it is determined that the communication frame has already passed through all nodes of the abnormal frame, the received communication frame is regarded as an abnormal frame, and an abnormal frame for transmitting an abnormal frame reception signal indicating that the abnormal frame has been received. The received signal transmitting means, and if it is the source of the communication frame, while describing its own node address in the source address description area, and among the passing bit information described in the passing bit information description area, Generates a communication frame that rewrites that information has been passed in the information location corresponding to itself, but is not the source of the communication frame. In the case where it is determined that the received communication frame has not yet passed the source of the plurality of nodes, the received communication frame is Assuming that the frame is a normal frame, a communication frame is generated in which the passing bit information described in the passing bit information description area of the communication frame is rewritten and described as having been passed in an information portion corresponding to itself. The gist of the present invention is to include a frame generation control unit and a frame transmission unit that transmits a communication frame generated by the frame generation control unit to a node located downstream of the frame generation control unit.

According to the first aspect of the present invention, first, when a communication frame is received by the frame receiving means, the frame discriminating means refers to the description content in the received communication frame and determines whether the received communication frame has a plurality of communication frames. Of the plurality of nodes, or a non-occupied frame that is not transmitted from any of the plurality of nodes.

As a result of the frame discrimination, when it is determined that the received communication frame is an occupied frame, the address comparing / determining means matches the source address described in the received communication frame with the own node address. It is compared to determine whether or not.

As a result of the address comparison determination, when it is determined that the source address and the own node address do not match, the all-node passing determining means sets the description in the passing bit information description area in the received communication frame. With reference to the passed bit information, it is determined whether the received communication frame has already passed through a plurality of nodes.

As a result of the all-node passing determination, when it is determined that the received communication frame has already passed the source of the plurality of all nodes, the abnormal frame reception signal transmitting means determines that the received communication frame is It regards the frame as an abnormal frame and sends out an abnormal frame reception signal indicating that the abnormal frame has been received.

Further, when the frame generation control means is the transmission source of the communication frame, the frame generation control means writes the own node address in the transmission source address description area and the passing bit described in the passing bit information description area. Among the information, while generating a communication frame that rewrites that it has already passed in the information location corresponding to itself, if the communication frame itself is not the source of the communication frame and the As a result, when it is determined that the received communication frame has not passed through all of the plurality of nodes, the received communication frame is regarded as a normal frame, and the passing bit information description area of the communication frame is determined. In the passing bit information described in (1), a communication frame is generated in which an information location corresponding to the communication bit is rewritten and described as having passed.

[0015] The frame transmitting means transmits the generated communication frame to a node located on the downstream side of the communication frame.

Therefore, according to the first aspect of the present invention, a ring format that allows cyclic transmission of a communication frame in a single direction between a plurality of nodes and allows a plurality of communication frames to coexist at the same time. Even when the present invention is applied to a ring network configured to be connected to each other so that data can be exchanged via a transmission line, a simple system configuration can be used to detect an abnormal frame that has fallen into a communication-disabled state and to detect the abnormal frame. It is possible to obtain a ring type network monitoring system capable of immediately recovering the abnormal frame.

Further, according to a second aspect of the present invention, the all-node passing determining means determines that the source address and the own node address match as a result of the comparison determination by the address comparing determining means. Referring to the passing bit information described in the passing bit information description area in the received communication frame to determine whether the received communication frame has already passed the sources of the plurality of nodes. That is the gist.

According to the second aspect of the present invention, the all-node passing determining means receives the signal when the address comparing and determining means determines that the source address and the own node address match. With reference to the passing bit information described in the passing bit information description area in the communication frame described above, it is determined whether the received communication frame has already passed through a plurality of nodes.

Further, according to a third aspect of the present invention, the abnormal frame reception signal transmitting means determines that the source address matches its own node address as a result of the comparison determination by the address comparison determining means. At the time, as a result of the determination of the all-node passing determination means, when it is determined that the received communication frame has not yet passed the source of the plurality of all nodes, the received communication frame is The gist is to regard an abnormal frame as an abnormal frame and transmit an abnormal frame reception signal indicating that the abnormal frame has been received.

According to the third aspect of the present invention, the abnormal frame reception signal sending means determines that the source address and the own node address match as a result of the comparison judgment by the address comparison judgment means. Therefore, when it is determined that the received communication frame has not yet passed the source of the plurality of all nodes, as a result of the determination by the all-node passing determination unit,
The received communication frame is regarded as an abnormal frame, and an abnormal frame reception signal indicating that the abnormal frame has been received is transmitted.

Furthermore, the invention according to claim 4 is characterized in that the frame generation control means determines that the source address and the own node address match as a result of the comparison judgment by the address comparison judgment means. When it is determined that the received communication frame has already passed the source of the plurality of nodes, as a result of the determination by the all-node passing determination unit, the communication frame transmitted by itself is The gist of the present invention is that it has a regression frame reproduction function of generating a new free token frame, which is a non-occupied frame, while discarding the received regression frame assuming that it has returned to its own origin.

According to the fourth aspect of the present invention, the frame generation control means determines that the source address matches its own node address as a result of the comparison determination by the address comparison determination means. Only when it is determined that the received communication frame has already passed the source of a plurality of all nodes,
Assuming that the communication frame transmitted by itself has returned to its own source and discarding the received return frame, it further has a return frame reproduction function of generating a new free token frame which is an unoccupied frame. Therefore, as a result of performing a regression frame reproduction process after double checking whether or not the received communication frame is a regression frame, a ring-type network monitoring system in which the reliability of the entire system is significantly improved Can be obtained.

Further, according to a fifth aspect of the present invention, when the abnormal frame reception signal indicating that an abnormal frame has been received is transmitted from the abnormal frame reception signal transmitting means, the frame generation control means receives the abnormal frame. The gist is that an abnormal frame reproducing function for generating a new free token frame, which is a non-occupied frame, is further provided while the abnormal frame is discarded.

According to the fifth aspect of the present invention, when the abnormal frame reception signal indicating that the abnormal frame has been received is transmitted from the abnormal frame reception signal transmitting means, the frame generation control means determines the received abnormal frame. It also has an abnormal frame reproduction function of generating a new free token frame, which is a non-occupied frame, while discarding, so that any abnormal state occurs in either the transmission path or the node. However, as a result of restoring an abnormal frame that occurs due to the occurrence of this abnormal situation and that circulates on a ring network semi-permanently if left unattended, it can be returned to a normal state. A ring-type network monitoring system with significantly improved reliability can be obtained.

Further, according to a sixth aspect of the present invention, the frame generation control means generates a new free token frame, which is the non-occupied frame, when there is transmission standby data waiting for transmission at its own node. Instead, the gist is to generate a communication frame including the transmission standby data.

According to the sixth aspect of the present invention, the frame generation control means replaces the generation of a new free token frame, which is an unoccupied frame, when there is transmission standby data waiting for transmission at its own node. Therefore, since the communication frame including the transmission waiting data is generated, the node receiving the regression frame transmitted by itself or the node receiving the abnormal frame transmits the communication frame including the data waiting for transmission at the own node. You will be given the opportunity to send,
As a result of increasing the chances of acquiring transmission rights for each node, it is possible to obtain a ring network in which the throughput of the entire system is further improved.

[0027] The invention according to claim 7 further comprises a plurality of communication monitoring means connected to the plurality of nodes, respectively, for monitoring a communication state of each node, and wherein the abnormal frame reception signal sending means comprises the abnormal frame receiving signal transmitting means. Sending an abnormal frame reception signal indicating that a frame has been received to the communication monitoring unit connected to each node, thereby notifying the communication monitoring unit connected to each node that the abnormal frame has been received; Is the gist.

According to the seventh aspect of the present invention, the abnormal frame reception signal transmitting means transmits an abnormal frame reception signal indicating that the abnormal frame has been received to the communication monitoring means connected to the own node, whereby the abnormal frame reception signal is transmitted. Since the fact that the frame has been received is notified to the communication monitoring means connected to the own node, the node receiving the abnormal frame notifies the communication monitoring means connected to the own node of the reception of the abnormal frame. As a result of the immediate notification, each of the plurality of communication monitoring means can not only grasp the occurrence state of the abnormal frame in the system in a timely manner,
Communication error processing can be performed by software.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a ring network monitoring system according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic block diagram showing the overall configuration of a ring network monitoring system according to the present invention. FIG. 2 is a block diagram of each node which is a main part of the present monitoring system. FIG. 4 is a diagram showing an example of a format of a communication frame circulating in the ring network. FIG. 4 is a state transition diagram of a communication frame circulating in the ring network. FIG. 5 is a flowchart showing a processing procedure of the monitoring system. FIG.

First, as shown in FIG. 1, a ring network monitoring system 1 according to the present invention mutually connects a plurality of nodes N1, N2, N3, and N4 via a ring-type transmission path 3. It has a communication monitoring function of monitoring the communication state of the ring network 2 configured to be connected to exchange data.

The ring-shaped transmission path 3 allows cyclic transmission of communication frames in a single direction such as the clockwise direction shown in FIG. 1 and a plurality of communication frames coexist on the transmission path 3 at the same time. It is configured to allow.

Each of the plurality of nodes N1, N2, N3, and N4 controls the operation of each node via a plurality of communication lines 5a, 5b, 5c, and 5d, respectively. A plurality of node controllers NC1, NC2, which function as communication monitoring means for monitoring the state, for example, whether or not each node has received an abnormal frame.
NC3 and NC4 are respectively connected.

One or two or more functional devices (not shown) are connected to each of the plurality of nodes N. Transmission is performed between the nodes N, between the functional devices, or between the functional devices and the node N. The data can be mutually exchanged via the path 3.

As the functional devices described above, for example, when the ring network 2 according to the present invention is applied to a vehicle, a portable telephone, a facsimile (FAX), a digital T
V, radio receiver, navigation device (NV), DV
D (Digital Video Disc or Di)
digital Versatile Disc) -ROM
Device, CD (Compact Disc) -ROM device, DAT (Digital Audio Tape)
recorder, MD (Mini Disc), digital signal processor (DSP) built-in audio amplifier, CAN (Controller Area Net)
(Work) interface, various sensors such as a direction sensor and a vehicle speed sensor, a monitor device, and various functional devices such as an in-vehicle personal computer can be appropriately adopted.

Here, the format of a communication frame circulating in the ring network 2 will be described with reference to FIG. 3. In the communication frame 31, a plurality of information description areas in which various types of information are described are set. The plurality of information description areas are mainly divided into two parts, that is, a token packet section 33 and a passing bit section 35.

The token packet section 33 includes a destination address description area DA in which the destination address of the destination node of the communication frame is described, a source address description area SA in which the source address of the source node of the communication frame 31 is described,
And a data description area in which various data including various instructions, control data, source data, and the like are described.

On the other hand, each time the communication frame 31 passes through the plurality of nodes N, the passing bit unit 35 outputs the corresponding information among the passing bit information indicating the passing status of the communication frame 31 for each of the plurality of nodes N. The portion is configured to have a passing bit information description area in which the description is rewritten under each node N.

Next, a block configuration inside each node that plays a major role in the monitoring system 1 will be described with reference to FIG. 2 by exemplifying the node N1. Since the block configuration inside each node N is common among the plurality of nodes N, the block configuration inside the node N1 will be representatively described, so that the description of the block configuration inside each of the plurality of nodes N will be made. Shall be replaced.

As shown in FIG. 2, the node N1 includes a receiving unit 11 functioning as a frame receiving unit, a frame determining unit 13 functioning as a frame determining unit, and a local node address storing unit functioning as a local node address storing unit. 15, an address comparing unit 17 functioning as an address comparing and determining unit, an all-node passing determining unit, and a passing bit checking unit 1 functioning as an abnormal frame received signal transmitting unit
9, a passing bit writing unit 21, a free token generation unit 25, and a frame control unit 27 constituting a frame generation control unit, and a transmission unit 29 functioning as a frame transmission unit
It is comprised including.

The receiving section 11 has a function of receiving the communication frame 31 from the node N4 located on the upstream side of the receiving section 11.

When the receiving unit 11 receives the communication frame 31, the frame determining unit 13
1, specifically, the source address SA, the received communication frame 31 is an occupied frame transmitted from any one of the plurality of nodes N including itself, or a plurality of nodes N. It has a function of determining whether the frame is a non-occupied frame that is not transmitted from any of the nodes N.

The own node address storage unit 15 has a function of storing the own node address in which a unique value is set for each of them.

The address comparing section 17 is provided for the frame discriminating section 1
When the received communication frame 31 is determined to be an occupied frame as a result of the frame determination of No. 3, the source address SA described in the received communication frame 31 and the self-address stored in the own node address storage unit 15 are stored. It has a function of determining whether the received communication frame 31 is a self-originated frame by comparing and determining whether or not the node address matches.

The pass bit checking unit 19 determines whether the source address and the own node address are not the same as a result of the comparison determination by the address comparing unit 17, or that the source address and the own node address are In any case in which it is determined that they match, by referring to the passing bit information described in the passing bit information description area in the received communication frame 31, the received communication frame is transmitted to a plurality of all nodes. All-node passing determination function for determining whether or not the element has already passed the element of N, and as a result of exerting this all-node passing determination function, when it is determined that the received communication frame is an abnormal frame, It has an abnormal frame reception signal transmission function of transmitting an abnormal frame reception signal indicating that an abnormal frame has been received.

When the address comparison unit 17 determines that the source address SA does not match its own node address as a result of the comparison determination by the address comparison unit 17, that is, the passing bit writing unit 21 If it is determined that the received communication frame 31 has not passed through the sources of all of the plurality of nodes N as a result of the determination by the passage bit check unit 19, the received communication The frame 31 is regarded as a normal frame, and among the passing bit information described in the passing bit information description area in the communication frame 31, the fact that the frame 31 has already passed at the information place N1 corresponding to itself is set to, for example, " It has a function of rewriting “0” to “1”.

The free token generation unit 25 determines that the source address SA does not match its own node address as a result of the comparison determination by the address comparison unit 17.
In other words, this is a case where it is determined that the communication frame 31 is not the transmission source of the communication frame 31, and the passing bit confirmation unit 19
As a result of the determination, when it is determined that the received communication frame 31 has already passed through a plurality of nodes N, the received communication frame 31 is regarded as an abnormal frame, and the received communication frame 31 is regarded as an abnormal frame. While the frame 31 is discarded, it has an abnormal frame reproducing function of generating a new free token frame which is a non-occupied frame.

When the frame control unit 27 is the source of the communication frame 31, the frame control unit 27 describes the own node address in the source address description area and the passing bit information described in the passing bit information description area. Of which
A transmission frame generation function of generating a communication frame 31 in which the information location N1 corresponding to itself is rewritten to indicate that it has already passed, and the result of the comparison determination by the address comparison unit 17, the source address SA and the own node address are When it is determined that they match, that is, the communication frame 31
Is determined to be the source of the communication frame 31. As a result of the determination by the passage bit checking unit 19, it is determined that the received communication frame 31 has already passed through the sources of the plurality of nodes N. When the communication frame 31 is transmitted, the communication frame 31 transmitted by itself is considered to have returned to its own, and the received communication frame 31 is discarded, while a new free token frame, which is an unoccupied frame, is generated. The function and the case where it is determined that the communication frame 31 is not the transmission source of the communication frame 31 are determined.
Is determined not to have passed through the elements of all the plurality of nodes N, the received communication frame 31 is regarded as a normal frame, and is described in the passing bit information description area of the communication frame 31. And a passing frame generation function of generating a communication frame 31 in which information indicating that the information has passed has been rewritten and described in an information location corresponding to the passing bit information.

The transmitting section 29 has a function of transmitting the communication frame 31 generated by the free token generating section 25 or the frame control section 27 to the node N2 located on its downstream side.

Next, the schematic operation of the present monitoring system 1 will be described in the clockwise direction indicated by the arrow in the block diagram of FIG. 4 from the node N1 which is the source node to the downstream side of the source node N1. An example in which the communication frame 31 is sequentially transmitted to each located node will be described with reference to FIG.

First, the node N1 describes its own node address "N1" in the source address description area SA, and has already passed the information bit N1 corresponding to itself among the passing bit information of the passing bit section 35. It generates a communication frame 31 in which "1" indicating the fact is described, and transmits the generated communication frame 31 to the node N2 located on its downstream side (step S1). At this time, “1000” is described in the passing bit information description area of the passing bit section 35.

When the node N2 receives the communication frame 31 from the node N1, the node N2 of the passing bit information of the passing bit section 35 of the communication frame 31 indicates "1" indicating that the communication frame 31 has already passed at the information place N2 corresponding to itself. Is generated, and the generated communication frame 31 is
The packet is transmitted to the node N3 located on the downstream side of itself (step S2). At this time, “1100” is described in the passing bit information description area of the passing bit section 35.

As in step S2, nodes N3 and N3
In N4, the communication frame 3 in which "1" indicating that the information has been passed is described in the information places N3 and N4 corresponding to each of them.
1 successively traverses the ring network 2 before returning to the source node 1 (step S
3, 4).

At this time, if the communication frame 31 returns while maintaining the normal state, the transmission bit information description area of the transmission bit section 35 in the return frame contains “111”.
1 "is described, and the source address SA matches the own node address. Therefore, the node 1 discards the received regression frame while assuming that the self-originated frame has returned to its own source. Then, a new free token frame, which is an unoccupied frame, is generated, and the generated free token frame is transmitted to the node N2 located on the downstream side of itself (step S5). At this time, the passing bit information description area of the passing bit section 35 is “000”.
Initialized to "0".

For example, if any abnormal condition occurs in either the transmission line 3c or the node N3, the information bit N3 corresponding to the node 3 in the passing bit portion 35 indicates "0" indicating that no passage has been made. After the communication frame 31 sequentially describes the ring network 2 and returns to the source node 1 (steps S3 'to S4').

At this time, the node N 1
By confirming the description content of the passing bit information in No. 5, it can be recognized that the node 3 could not receive. Then, the node N that has received the abnormal frame
1 generates a new free token frame that is a non-occupied frame while discarding the received abnormal frame in the same manner as in step S5 described above, and transmits the generated free token frame to a node located on its downstream side. Transmit to N2.

When an abnormal frame whose source address SA is garbled as "XX" or the like returns to the node N1 due to occurrence of some trouble, the communication frame 31 which has returned to the node N1 is returned. The source address “XX” described in the field “N” is the own node address “N”.
1 ", but even in such a case, the node N1 which has received the abnormal frame,
5 by confirming the contents of the passing bit information description, the "1"
If “111” is described, it is considered that the abnormal frame has returned to its own element, and the received abnormal frame is discarded while a new free talk which is a non-occupied frame is discarded, as in step S5 described above. A free token frame is generated, and the generated free token frame is transmitted to the node N2 located on the downstream side of itself.

As described above, according to the ring network monitoring system of the present invention, with a simple system configuration, an abnormal frame that has fallen into a communication disabled state is detected, and the detected abnormal frame is immediately recovered. be able to.

Next, the operation inside each node that plays a major role in the ring network monitoring system according to the present invention will be described in more detail with reference to FIG.

In step S11, the receiving unit 11
A frame reception waiting process for waiting to receive a communication frame 31 transmitted from a node located on the upstream side of itself is executed.

When the communication frame 31 is received from the node located on the upstream side during the reception standby in step S11, in step S12 the frame discriminating unit 13
Refers to the description content in the received communication frame 31, for example, the source address SA, and
1 is an occupied frame transmitted from any of the plurality of nodes N including itself, or a plurality of nodes N
Of the non-occupied frames not transmitted from any of the nodes, that is, a free token frame.

As a result of the frame discrimination processing in step S12, when it is determined that the received communication frame 31 is a free token frame which is an unoccupied frame, in step S16, the frame determination unit 13 determines whether the received communication frame 31 Is transmitted via the frame control unit 27 as it is without performing any processing.
9, the transmission unit 29 relays the received communication frame 31 to a node located on the downstream side of the transmission unit 29, and ends all frame processing.

On the other hand, when it is determined that the received communication frame 31 is an occupied frame as a result of the frame determination processing in step S12, the address comparing unit 17 determines in step S13 that the received communication frame 31 has been described in the received communication frame 31. Source address SA and own node address storage unit 1
An address comparison determination process is performed to determine whether or not the own node address stored in No. 5 matches. In addition,
In step S13, a comparison is made to determine whether the source address SA matches the own node address,
The communication frame 31 received in step S11 determines whether or not the communication frame 31 is a self-originated frame that has returned to its own origin after circulating on the ring network 2 after being transmitted by the own node.

As a result of the address comparison determination processing in step S13, when it is determined that the source address SA does not match the own node address, that is, in step S13
When it is determined that the communication frame 31 received in step 11 is not a communication frame that has returned to its own origin by circulating on the ring network 2 after its own node has transmitted, in step S14 Referring to the passing bit information described in the passing bit information description area in the received communication frame 31, it is determined whether or not the received communication frame has already passed through a plurality of nodes N. Execute node passage determination processing. In step S14, if the received communication frame 31 is not a self-originated frame, and if it is a normal frame, the passing bit information described in the passing bit information description area in the received communication frame 31 is used. In view of the fact that the content cannot indicate that the content has already passed through a plurality of nodes N, the communication frame 31 received in step S11 is determined by executing the all-nodes pass determination processing. Is determined to be an abnormal frame including an abnormal part.

When it is determined that the received communication frame 31 has not passed through all of the plurality of nodes N as a result of the all-node passing determination in step S14, in step S15 the passing bit writing unit is determined. Reference numeral 21 indicates that the received communication frame 31 is regarded as a normal frame, and has already passed the information portion corresponding to itself among the passing bit information described in the passing bit information description area in the communication frame 31. Is described, for example, by rewriting “0” to “1”.

Then, in step S16, the frame control unit 27 transfers the communication frame 31 in which the passing bit unit 35 has been rewritten in step S14 to the transmission unit 29. In response, the transmission unit 29 transfers the communication frame 31. The communication frame 31 is transmitted to a node located on the downstream side of the communication frame 31,
End all frame processing.

On the other hand, as a result of the address comparison determination processing in step S13, when it is determined that the source address SA matches the own node address, that is, the communication frame 31 received in step S11 is When it is determined that the communication frame is a communication frame that has circulated on the ring type network 2 and returned to its own after transmitting from the own node, it is determined in step S17 that all nodes pass through in the same manner as in step S14. Execute the process.

When it is determined that the received communication frame 31 has already passed the source of the plurality of all nodes N as a result of the all-node passing determination in step S17, the frame control unit 27 determines in step S18 that The received communication frame 31 is regarded as having returned to its original state while maintaining a normal state, and the received regression frame is collected and discarded. In step S19, a new free token frame, which is an unoccupied frame, is rewritten. Then, in step S16, the free token frame generated in step S19 is transferred to the transmitting unit 29. In response to this, the transmitting unit 29 transmits the transferred free token frame to a node located on its downstream side. And finishes all frame processing.

Here, in steps S13 and S17, after double checking whether or not the received communication frame is a regression frame, regression frame reproduction processing is performed in steps S18 to S19. It is possible to obtain a ring-type network monitoring system with significantly improved performance.

On the other hand, as a result of the all-node passing determination in step S14, it is determined that the received communication frame 31 has already passed the source of the plurality of all nodes N, or As a result of the node passage judgment,
When it is determined that the received communication frame 31 has not yet passed through the sources of the plurality of all nodes N, it is determined in step S
In 20, the passing bit check unit 19 regards the received communication frame 31 as an abnormal frame, and sends an abnormal frame reception signal indicating that the abnormal frame has been received to the node controller NC connected thereto. By executing the abnormal frame reception signal transmission process, the fact that the abnormal frame has been received is notified to the node controller NC.

As described above, the node receiving the abnormal frame immediately notifies the node controller NC connected to the own node of the reception of the abnormal frame, and as a result, each of the plurality of node controllers NC In addition to being able to grasp the occurrence status of an abnormal frame in the present system in a timely manner, it is possible to perform communication abnormal processing by software.

After the error occurrence notification in step S20, the free token generation unit 25 generates a new free token frame, which is an unoccupied frame, in the same manner as in step S19 described above, and in response to this, the frame control unit 25 27 transfers the free token frame generated in step S19 to the transmitting unit 29 in step S16, and in response to this, the transmitting unit 29 sends the transferred free token frame to a node located on its downstream side. Then, all the frame processing is completed.

As described above, when the received communication frame 31 is an abnormal frame, a new free token frame is generated, and the generated free token frame, which is a non-occupied frame, is located downstream of the own frame. Therefore, even if any abnormal state occurs in either the transmission path 3 or the node N, the transmission is caused to occur and is left as it is. As a result, an abnormal frame circulating on the ring network 2 semi-permanently can be promptly returned to a normal state.
It is possible to obtain a ring network monitoring system in which the reliability of the entire system is significantly improved.

In step S19, the free token generation unit 25 or the frame control unit 27 determines whether the communication frame 31 transmitted by itself returns to its own source or the received communication frame 31 is an abnormal frame. Has exemplified a form in which a new free token frame is generated, but the present invention is not limited to this form. When data in the data exists, a mode of generating a communication frame including the transmission data may be adopted. In this way, the node that has received the regression frame transmitted by itself or the node that has received the abnormal frame is given a transmission opportunity of a communication frame including data that is waiting to be transmitted in its own node. As a result, it is possible to obtain a ring network in which the throughput of the entire system is further improved.

As described above, according to the ring network monitoring system of the present invention, cyclic transmission of a communication frame in a single direction is allowed between a plurality of nodes, and a plurality of communication frames are simultaneously transmitted. Even when the present invention is applied to a ring network configured to be connected to each other via a ring-type transmission path that allows coexistence, the communication becomes impossible due to a simple system configuration. In addition to detecting abnormal frames,
A ring-type network monitoring system capable of immediately recovering a detected abnormal frame can be obtained.

The present invention is not limited to the above-described embodiment, but can be embodied in an appropriately modified form within the scope of the claims.

That is, for example, in this embodiment, in the example shown in FIG. 3, the time interval between the plurality of communication frames 31 has a vacant time of a predetermined interval. Without being limited to the form, for example,
As a time interval between the plurality of communication frames 31, it is needless to say that a form in which a plurality of communication frames 31 are tightly coupled with each other without any vacant time or with no vacant time can be adopted. No.

[0078]

According to the first aspect of the present invention, a ring-type communication system that allows cyclic transmission of a communication frame in a single direction between a plurality of nodes and allows a plurality of communication frames to coexist at the same time. Even when the present invention is applied to a ring network configured to be connected to each other so that data can be exchanged via a transmission line, with a simple system configuration, it is possible to detect an abnormal frame that has fallen out of communication,
A ring-type network monitoring system capable of immediately recovering a detected abnormal frame can be obtained.

According to the fourth aspect of the present invention, as a result of performing the regression frame reproduction process after double checking whether the received communication frame is a regression frame,
It is possible to obtain a ring network monitoring system in which the reliability of the entire system is significantly improved.

Further, according to the fifth aspect of the present invention, even if any abnormal state occurs in either the transmission line or the node, the abnormal state occurs due to the occurrence of the abnormal state, and is left as it is. As a result, an abnormal frame that circulates on the ring network semi-permanently can be returned to a normal state. As a result, a ring network monitoring system with significantly improved reliability as a whole system can be obtained. it can.

Furthermore, according to the invention of claim 6, the node that has received the regression frame transmitted by itself or the node that has received the abnormal frame is provided with a communication frame including data that is waiting to be transmitted at its own node. As a result, transmission opportunities are provided and opportunities for acquiring transmission rights for each node are expected to increase. As a result, it is possible to obtain a ring network in which the throughput of the entire system is further improved.

According to the seventh aspect of the present invention, the node that has received the abnormal frame immediately notifies the communication monitoring means connected to its own node that the abnormal frame has been received. Each of the communication monitoring means has an extremely excellent effect that, in addition to being able to grasp the occurrence state of the abnormal frame in the present system in a timely manner, it becomes possible to perform the communication abnormal processing by software.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing the entire configuration of a ring network monitoring system according to the present invention.

FIG. 2 is a block configuration diagram of each node that is a main part of the monitoring system.

FIG. 3 is a diagram showing an example of a format of a communication frame circulating in the ring network.

FIG. 4 is a state transition diagram of a communication frame circulating in the ring network.

FIG. 5 is a flowchart illustrating a processing procedure of the monitoring system.

[Explanation of symbols]

Reference Signs List 1 monitoring system 2 ring network 3 transmission line 5 communication line 11 receiving unit (frame receiving unit) 13 frame discriminating unit (frame discriminating unit) 15 own node address storage unit (own node address storing unit) 17 address comparing unit (address comparison) Judgment Means) 19 Passed Bit Confirmation Unit (All Node Passage Judgment Means and Abnormal Frame Received Signal Transmission Means)) 21 Passed Bit Write Unit (Frame Generation Control Unit) 25 Free Token Generation Unit (Frame Generation Control Unit) 27 Frame Control Unit (frame generation control unit) 29 transmission unit (frame transmission unit) 31 communication frame 33 token packet unit 35 passing bit unit SA source address N node NC node controller (communication monitoring unit)

Claims (7)

[Claims] 1. A ring-type network monitoring system for monitoring a communication state of a ring-type network configured by connecting a plurality of nodes to each other via a ring-type transmission path so that data can be exchanged with each other, The transmission path is configured to allow cyclic transmission of a communication frame in a single direction, and to allow a plurality of communication frames to coexist on the transmission path at the same time. A source address description area in which the source address of the source node is described, and a passing bit indicating a passing state of the communication frame for each of the plurality of nodes each time the communication frame passes through the plurality of nodes. And a passing bit information description area in which a corresponding information portion of the information is rewritten under each node. Each of the plurality of nodes includes: a frame receiving unit that receives the communication frame from a node located upstream of itself; a self-node address storage unit that stores a self-node address in which a unique value is set for each of the plurality of nodes; When a communication frame is received by means,
With reference to the description content in the received communication frame, the received communication frame is, among the plurality of nodes,
Frame determining means for determining whether an occupied frame transmitted from any node including itself or an unoccupied frame not transmitted from any of the plurality of nodes; and As a result of the frame determination, when the received communication frame is determined to be an occupied frame, the source address described in the received communication frame and the own node address stored in the own node address storage unit are Address comparing and judging means for judging whether or not the address coincides with each other. When the result of the comparison judgment by the address comparing and judging means indicates that the source address and the own node address do not match, the received The received communication frame is referred to by referring to the passing bit information described in the passing bit information description area in the communication frame. All-node passage determining means for determining whether the system has already passed the source of the plurality of all nodes, and as a result of the determination by the all-node passing determining means, the received communication frame When it is determined that the original communication has already passed, the received communication frame is regarded as an abnormal frame, and an abnormal frame reception signal transmitting means for transmitting an abnormal frame reception signal indicating that the abnormal frame has been received. If it is the source of the communication frame, it describes its own node address in the source address description area and, among the passing bit information described in the passing bit information description area, In this case, a communication frame is generated in which the communication frame is rewritten to indicate that the communication frame has already passed. When it is determined that the received communication frame has not passed through all the nodes of the plurality of nodes as a result of the determination by the node passage determination means, the received communication frame is regarded as a normal frame. Frame generation control means for generating a communication frame in which the passing bit information described in the passing bit information description area of the communication frame rewrites and describes the fact that the communication bit has been passed in an information location corresponding to itself; And a frame transmission means for transmitting the communication frame generated by the frame generation control means to a node located on the downstream side of the communication frame. 2. The all-node pass-through determination means, when a result of the comparison determination by the address comparison determination means determines that the source address and the own node address match, the received communication frame And determining whether or not the received communication frame has already passed the source of the plurality of nodes by referring to the passing bit information described in the passing bit information description area. 2. The monitoring system for a ring network according to claim 1. 3. The abnormal frame reception signal transmission means, when the address comparison determination means determines that the source address and the own node address match as a result of the comparison determination, As a result of the determination by the node passage determination unit, when it is determined that the received communication frame has not yet passed the elements of the plurality of nodes, the received communication frame is regarded as an abnormal frame. The ring network monitoring system according to claim 2, wherein an abnormal frame reception signal indicating that an abnormal frame has been received is transmitted. 4. The method according to claim 1, wherein the frame generation control means determines that the source address and the own node address match as a result of the comparison determination by the address comparison determination means, As a result of the determination by the determining means, when it is determined that the received communication frame has already passed the elements of the plurality of nodes, it is considered that the communication frame transmitted by itself has returned to its element. 3. The ring-type network according to claim 2, further comprising a regression frame reproducing function of generating a new free token frame that is an unoccupied frame while discarding the received regression frame. Monitoring system. 5. When the abnormal frame reception signal indicating that an abnormal frame has been received is transmitted from the abnormal frame reception signal transmitting unit, the frame generation control unit discards the received abnormal frame. ,
4. The monitoring system for a ring network according to claim 1, further comprising an abnormal frame reproducing function of generating a new free token frame that is a non-occupied frame. 6. When there is transmission standby data waiting for transmission at its own node, the frame generation control means replaces the generation of a new free token frame, which is the non-occupied frame, with the transmission standby data. 5. A communication frame including a communication frame is generated.
Or the monitoring system for a ring network according to any one of the above items 5. 7. The communication apparatus according to claim 1, further comprising a plurality of communication monitoring units respectively connected to the plurality of nodes and respectively monitoring a communication state of each of the nodes, wherein the abnormal frame reception signal sending unit transmits an abnormal signal indicating that the abnormal frame has been received. 2. The communication monitoring means connected to each node is notified that an abnormal frame has been received by sending a frame reception signal to the communication monitoring means connected to each node. The monitoring system for a ring network according to any one of claims 1 to 6.