CN109923839B - Network management system and network management method - Google Patents

Abstract

A network management system (101) is provided with communication devices (11-14) connected in a loop in a communication network, wherein the communication device (14) performs a path determination based on the relay order of frames from a priority device to the communication device (14), the priority device is the communication device (11) which is set with the highest 1 st highest priority among device priorities set for the communication devices (11-14) in the communication network, the path determination is performed to determine whether or not the communication device (14) is connected to a communication path of the communication device which has relayed the most from the priority device, and when the communication device (14) determines that the communication device has been connected to the communication path of the communication device which has relayed the most from the priority device, any port (P14b) in the loop among ports (P14a, P14b) is set as the end of the communication network.

Description

Network management system and network management method

Technical Field

The present invention relates to a network management system and a network management method for setting a communication path of a communication network.

Background

A communication network including a ring in which nodes are connected in a ring shape exists. Since such a communication network cannot discard unnecessary data in the loop, unnecessary data may be continuously relayed. Therefore, it is desirable to discard unnecessary data by appropriately setting a communication path in a communication network.

In the network system described in patent document 1, relay of user data performed on a port side of a node side of a ring network to which each node is connected is prevented, transmission and reception are performed in a priority order in which the node is set as a master node, and whether or not to migrate to the master node is determined based on the received priority order.

Patent document 1: international publication No. 2006/072996

Disclosure of Invention

However, patent document 1, which is the above-mentioned conventional technique, has a problem that an appropriate communication path cannot be set when a plurality of loops are formed.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a network management system capable of setting an appropriate communication path even when a plurality of loops are formed.

In order to solve the above problems, the present invention provides a network management system including a plurality of communication devices connected to form a 1 st loop in a communication network. The network management system of the present invention includes a relay device that has a communication standard different from that of the communication device, is connected to the 1 st loop and the 2 nd loop in the communication network, and relays frames to the 1 st loop and the 2 nd loop. In the network management system according to the present invention, the communication device includes a control unit that performs a path determination for determining whether or not the communication device is connected to a communication path of a communication device that has relayed the most from the priority device, based on the relay order of frames from the priority device to the communication device, the priority device being the communication device to which the highest 1 st highest priority is set among device priorities set for each communication device in the communication network. Further, a network management system according to the present invention includes: a storage unit that stores a 2 nd highest priority, the 2 nd highest priority being a highest device priority identified by the device itself among the device priorities; and a communication unit which transmits a 1 st frame and receives a 2 nd frame via the port between the communication unit and another communication device closest to the communication unit in the 1 st loop. In the network management system according to the present invention, the communication unit transmits the 1 st frame in which the 2 nd highest priority is stored to the other communication device, and receives the 2 nd frame in which the 3 rd highest priority is stored from the other communication device, where the 3 rd highest priority is the highest device priority identified by the other communication device among the device priorities. In the network management system according to the present invention, the control unit performs the path determination based on the number of relay stages of the frames from the priority device to the own device, the 2 nd highest priority, and the 3 rd highest priority, and when it is determined that the own device is connected to the communication path of the communication device that has relayed the most from the priority device, the control unit sets any one of the ports in the 1 st loop as the end of the communication network. In the network management system according to the present invention, the communication unit broadcasts the 1 st frame, and does not transfer the 2 nd frame to another communication device even if the 2 nd frame is received, and the relay device transfers the 2 nd frame to another communication device if the relay device receives the 2 nd frame.

ADVANTAGEOUS EFFECTS OF INVENTION

The network management system related to the invention obtains the following effects: even when a plurality of loops are formed, an appropriate communication path can be set.

Drawings

Fig. 1 is a block diagram showing a configuration of a communication device according to embodiment 1 of the present invention.

Fig. 2 is a diagram showing a configuration example of the network management system according to embodiment 1.

Fig. 3 is a flowchart showing a procedure of transmitting and receiving an arbitration frame according to embodiment 1.

Fig. 4 is a flowchart showing a procedure of the port setting processing according to embodiment 1.

Fig. 5 is a diagram showing a state in which a loop is closed in the network management system according to embodiment 1.

Fig. 6 is a diagram showing another example of the configuration of the network management system according to embodiment 1.

Fig. 7 is a diagram showing a state in which a loop is closed in the network management system having another configuration according to embodiment 1.

Fig. 8 is a flowchart showing a procedure of transmitting and receiving an arbitration frame according to embodiment 2.

Fig. 9 is a flowchart showing a procedure of the port setting processing according to embodiment 2.

Fig. 10 is a diagram showing an example of a hardware configuration of a control unit included in the communication device according to the embodiment.

Detailed Description

Hereinafter, a network management system and a network management method according to an embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to these embodiments.

Embodiment mode 1

Fig. 1 is a block diagram showing a configuration of a communication device according to embodiment 1 of the present invention. Fig. 1 shows a functional configuration of a communication device 10X arranged in a network management system 101 described later. The communication device 10X is connected to another communication device 10X. Hereinafter, the communication device 10X may be referred to as a station.

The network management system 101 is a system that manages a ring network in which a plurality of communication devices 10X are connected in a loop in a communication network. In the communication network of the network management system 101, a plurality of communication apparatuses 10X are connected via communication lines. In the following description, the communication network is referred to as a network.

Each communication device 10X transmits and receives various data including various information to and from the other communication device 10X closest to the loop, and thereby executes the path setting in the network management system 101 and the arbitration process of the N/w (network) management station that manages the network. The communication device 10X nearest to the loop is a communication device 10X adjacent to the loop or a communication device 10X adjacent to the loop via a plurality of types of devices such as a relay device. In other words, the communication device 10X closest to the other communication device 10X in the loop is the communication device 10X having the shortest communication path from the own communication device among the communication devices 10X in the loop. The arbitration process of the N/W management station is a process of setting the N/W management station as any one of the communication devices 10X.

The N/W management station is a device that executes various settings in the network. The N/W management station manages how the communication device 10X connected to the network management system 101 is connected to and performs communication. The N/W management station may set what data each communication device 10X transmits and receives.

In the network management system 101, any one of the communication devices 10X serves as an N/W management station. Therefore, each communication device 10X is a candidate of the N/W management station. In other words, the communication device 10X in the network management system 101 is an N/W management candidate station before setting the N/W management station.

The communication device 10X includes a communication unit 51, a control unit 52, and a storage unit 53, the communication unit 51 performs communication with the communication device 10X nearest to the loop, the control unit 52 performs path setting in the network and arbitration of the N/W management station, and the storage unit 53 stores various data.

The control unit 52 controls the communication unit 51 and the storage unit 53. Therefore, the communication unit 51 transmits data in accordance with an instruction from the control unit 52, and the storage unit 53 stores or changes data in accordance with an instruction from the control unit 52.

The control unit 52 executes the path setting in the network and the arbitration process of the N/W management station with the communication device 10X. Specifically, the control unit 52 changes the data stored in the storage unit 53 based on an arbitration frame, which will be described later, received from the communication device 10X closest to the loop and the data stored in the storage unit 53 of the communication device 10X. The control unit 52 generates an arbitration frame using a part of the data stored in the storage unit 53, and transmits the arbitration frame to the nearest communication device 10X in the loop. Further, the control unit 52 performs a route determination for determining whether or not the communication route from the N/W management station to the own station is the communication route of the communication device 10X which is most relayed in the loop, as viewed from the N/W management station. Then, the control unit 52 controls opening and closing of the port, which will be described later, based on the path determination. In this way, the control unit 52 controls the opening and closing of the port and the transmission of the arbitration frame based on the data stored in the storage unit 53 and the received arbitration frame, thereby executing the path setting in the network and the arbitration process of the N/W management station.

Examples of the data stored in the storage unit 53 are data set for each communication device 10X and data set for each port provided in the communication device 10X. The data set for each communication device 10X is 3 of the own station priority, the highest priority, and the transmission time of the N/W most priority station. The priority is a priority order for each station to become an N/W management station, and the higher the priority, the more easily the station becomes an N/W management station. The data set for each port is 2 relay numbers and port numbers. In the following description, the transmission time of the N/W most-priority station is referred to as a transmission time.

(local site priority)

The local station priority is a priority which the communication device 10X, that is, the local station has for becoming the N/W management station. This own station priority is a device priority set for each communication device 10X, and does not overlap with own station priorities of other stations as the other communication devices 10X. In other words, different own-station priorities are set for each communication device 10X in the network. In the network, the communication device 10X having a high priority of its own station becomes an N/W management station by arbitration. Each communication device 10X in the network sets its own station priority before the communication path setting process.

(highest priority)

The highest priority is the priority with which the own station has the highest priority among the priorities of the own stations identified in the network. That is, the highest priority is the own-station priority of the communication apparatus 10X having the highest own-station priority in the network among the own-station priorities of the communication apparatuses 10X identified by the own station.

The communication device 10X cannot recognize another station before the communication path setting process. Therefore, the communication device 10X recognizes only the own station priority of the own station when the setting of the communication path is started. Therefore, the communication device 10X sets the own-station priority of the own station to the highest priority at the start of setting the communication path. In other words, the initial value of the priority of the own station is the highest priority of the own station. When the communication device 10X identifies another station after the start of setting of the communication path, the highest own-station priority is found from the own-station priority of the identified another station and the own-station priority of the own station, and the highest priority is set.

In this way, the communication device 10X sets the own station priority having the highest priority order as the highest priority order from among the own station priorities that have been identified. In the following description, the communication device 10X having the highest priority of its own station in the network identified by its own station is referred to as the N/W most-priority station. The N/W most preferred station is the master station, and is the communication apparatus 10X of which the own station, which is the N/W management station among the communication apparatuses 10X, has the highest priority.

Of the own-station priorities set for each communication device 10X in the network, the highest own-station priority identified by the own station is the 2 nd highest priority. The own station priority that actually indicates the highest priority among the own station priorities is the 1 st highest priority. In other words, the own station priority as the priority device of the N/W most priority station is the 1 st highest priority. Among the own station priorities, the highest priority identified by the other communication device 10X is the 3 rd highest priority. The control unit 52 determines the communication path based on the number of relay stages, the 2 nd highest priority, and the 3 rd highest priority.

(time of transmission)

The transmission time is a time when the N/W most-prior station transmits data to the nearest communication device 10X in the loop. Before the communication path setting process, the communication device 10X is the N/W most-preferred station. Therefore, the communication device 10X sets the current time of the own station as the transmission time when the setting of the communication path is started.

(Relay series)

The relay order is the relay order of data from the communication device 10X set to the highest priority. The number of data relay stages is counted at the port provided in each communication device 10X. Therefore, if the port receives data from the closest communication device 10X in the loop, the number of relay stages of the received data is increased by 1 stage. Thus, the number of stages increases by 1 stage each time data transmitted and received in the network is transmitted and received via the communication device 10X. The number of relay stages is not set at the start of setting the communication path. In other words, the initial value of the number of relay stages is set to 0 stage at the start of setting the communication path.

The port is disposed in the communication device 10X, receives data transmitted from the communication device 10X nearest in the loop, takes in the local station, and transmits data of the local station to the communication device 10X nearest in the loop. Since each communication device 10X is arranged in a network connected in a ring, it is connected to at least 2 other communication devices 10X. Therefore, each communication device 10X has at least 2 ports.

(Port number)

The port number is a number assigned to a port provided in the communication device 10X. The port number is set for each port so as not to overlap within 1 communication device 10X.

The communication device 10X is set with its own station priority before the start of setting of the communication path. Further, the communication device 10X sets a port number before the start of setting of the communication path. Further, if the communication device 10X starts setting of the communication path, the highest priority, the transmission time, and the number of relay stages are updated based on the content of the data received from the communication device 10X nearest to the loop.

In this way, each communication device 10X stores 3 pieces of data set for each communication device 10X and 2 pieces of data set for each port. Each communication device 10X broadcasts and transmits a 1 st frame, which stores all or part of the own station priority, the highest priority, the transmission time, and the relay order, to the other communication devices 10X. Each communication device 10X receives a 2 nd frame storing all or a part of the own station priority, the highest priority, the transmission time, and the relay order from another communication device 10X. The communication unit 51 performs transmission of the 1 st frame and reception of the 2 nd frame via the port with the nearest other communication device 10X in the loop. The 1 st frame transmitted by the communication unit 51 is any of the 1 st to 3 rd arbitration frames described later generated by the communication device 10X, and the 2 nd frame received by the communication unit 51 is any of the 1 st to 3 rd arbitration frames described later generated by the other communication device 10X nearest to the loop.

Further, each communication apparatus 10X does not transfer the received arbitration frame to another communication apparatus 10X even if it receives the arbitration frame from another communication apparatus 10X that is closest in the loop. In other words, the communication device 10X does not perform relaying of the arbitration frame.

Next, the configuration of the network management system 101 will be described. Fig. 2 is a diagram showing a configuration example of the network management system according to embodiment 1. An example of the network management system 101 is an FA network used in the field of FA (factory automation) for automating a production process of a factory. Here, a case where the network management system 101 includes 4 communication devices 10X will be described. In FIG. 2, communication devices 11 to 14 are communication devices 10X.

In the network management system 101, communication devices 11 to 14 are connected in a ring shape to form a loop. Specifically, the communication device 11 is connected to the communication device 12, and the communication device 12 is connected to the communication device 14. The communication device 14 is connected to the communication device 13, and the communication device 13 is connected to the communication device 11.

The communication device 11 includes ports P11a and P11b, and the communication device 12 includes ports P12a and P12 b. The communication device 13 includes ports P13a and P13b, and the communication device 14 includes ports P14a and P14 b.

Further, the port P11b is connected to the port P12a via a communication line, and the port P12b is connected to the port P14 b. Further, the port P14a is connected to the port P13b, and the port P13a is connected to the port P11 a.

In a network including a loop such as the network management system 101, if a frame circulates in the loop, a band is compressed, and therefore, each of the communication devices 11 to 14 sets a communication path capable of preventing the frame from circulating. Further, each of the communication devices 11 to 14 sets a unique N/W management station serving as communication management in the network management system 101 by arbitration.

Here, the arbitration frame is explained. The network management system 101 transmits and receives any of the 1 st to 3 rd arbitration frames to and from the communication apparatuses 10X that are closest to each other in the loop. The 1 st to 3 rd arbitration frames are examples of arbitration frames. The 1 st arbitration frame is an arbitration frame broadcast-transmitted to the other communication device 10X closest to the communication device 10X in the loop when the communication device 10X starts setting the communication path. The 2 nd and 3 rd arbitration frames are arbitration frames broadcast by the communication device 10X that has received any of the 1 st to 3 rd arbitration frames in accordance with the contents of the received 1 st to 3 rd arbitration frames. Therefore, if the communication device 10X starts setting of the communication path, it transmits the 1 st arbitration frame and receives any of the 1 st to 3 rd arbitration frames. Also, the communication device 10X transmits the 2 nd or 3 rd arbitration frame if receiving any of the 1 st to 3 rd arbitration frames. In the following description, any one of the 1 st to 3 rd arbitration frames is referred to as an nth arbitration frame.

The nth arbitration frame is a data frame transmitted and received between the communication devices 10X that are closest to each other in the loop. By receiving the nth arbitration frame in the network management system 101, the path setting and the setting of the N/W management station in the network management system 101 are performed.

The communication devices 11 to 14 broadcast and transmit the nth arbitration frame from all ports in a cycle C1 shorter than the bit time Tx. The specific time Tx and the period C1 are set based on the number of communication devices 10X arranged in the network management system 101 and the total distance of the communication paths that the network management system 101 has. Therefore, the specific time Tx and the period C1 vary according to the configuration of the network management system 101.

The communication device 11 broadcasts the nth arbitration frame from the ports P11a, P11b, and the communication device 12 broadcasts the nth arbitration frame from the ports P12a, P12 b. In addition, the communication device 13 broadcasts and transmits the nth arbitration frame from the ports P13a, P13b, and the communication device 14 broadcasts and transmits the nth arbitration frame from the ports P14a, P14 b. By broadcasting the nth arbitration frame, even in a case where a HUB as a relay device is arranged in the loop, the HUB does not need to interpret the communication content of the nth arbitration frame. The HUB is a communication unit having a communication standard different from that of the communication devices 11 to 14. The HUB in embodiment 1 transmits the nth arbitration frame from the appropriate port if the nth arbitration frame is received at the port, and transfers the nth arbitration frame without changing it. The port adapted to transmit the nth arbitration frame may be a port other than the port that received the nth arbitration frame, or may be the port that received the nth arbitration frame. In the following description, a case will be described in which a port that transmits an nth arbitration frame is a port other than a port that receives the nth arbitration frame. In the following description, a port that receives the nth arbitration frame is sometimes referred to as a reception port.

Next, a communication processing procedure of the communication device 10X arranged in the network management system 101 will be described with reference to fig. 3 and 4. Since the communication devices 11 to 14 perform the same processing, the communication processing procedure of the communication device 11 will be described here.

Fig. 3 is a flowchart showing a procedure of transmitting and receiving an arbitration frame according to embodiment 1. Fig. 4 is a flowchart showing a procedure of the port setting processing according to embodiment 1. The communication devices 11 to 14 arranged in the network management system 101 store the own station priority, the highest priority, the transmission time, the number of relay stages, and the port number, respectively. Then, if the communication devices 11 to 14 start setting of the communication paths, the 1 st arbitration frame storing the priority of the own station, the highest priority, the transmission time, and the relay order is broadcast to the nearest other communication devices 11 to 14 in the network management system 101. The number of relay stages stored in the 1 st arbitration frame by the communication devices 11 to 14 is 0.

Each of the communication devices 11 to 14 receives the 1 st arbitration frame from the nearest other communication device 10X in the network management system 101. In addition, if the communication devices 11 to 14 receive the 1 st arbitration frame, they transmit the 2 nd or 3 rd arbitration frame to the nearest other communication device 10X in the loop.

Since the communication devices 11 to 14 perform the same processing, a communication processing procedure in the communication device 11 is explained here. In step S100, if the communication unit 51 of the communication device 11 receives the nth arbitration frame from the other communication devices 12, 13 closest to the loop, the communication unit 51 transmits the received nth arbitration frame to the control unit 52. The communication unit 51 receives the 1 st arbitration frame from the communication device 12 first, and then receives the 2 nd or 3 rd arbitration frame. The communication unit 51 receives the 1 st arbitration frame from the communication device 13 first, and then receives the 2 nd or 3 rd arbitration frame.

Here, the 1 st to 3 rd arbitration frames are explained.

(arbitration frame 1)

The 1 st arbitration frame stores the following 4 data.

Priority of own site

Degree of optimality

Time of transmission

Number of relay stages

The data stored in the 1 st arbitration frame is an initial value set in the communication device 11.

(arbitration frame 2)

The 2 nd arbitration frame stores the following 4 data.

Degree of optimality

Time of transmission

Number of relay stages

Priority of own site

When the highest priority included in the received N-th arbitration frame is higher than the highest priority stored by the station, the 2 nd arbitration frame is transmitted. In other words, the communication device 11 transmits the 2 nd arbitration frame when the received highest priority is higher than the saved highest priority. Therefore, the top priority and the transmission time stored in the 2 nd arbitration frame are the same as those included in the received N-th arbitration frame. In this case, the number of relay stages stored in the 2 nd arbitration frame is the number of relay stages obtained by adding 1 stage to the number of relay stages included in the received N th arbitration frame. Further, the 2 nd arbitration frame is also transmitted in a case where the received highest priority and the stored highest priority are the same and a specific condition is satisfied.

(arbitration frame 3)

The 3 rd arbitration frame stores the following 4 data.

Priority of own site

Degree of optimality

Time of transmission

Number of relay stages

And transmitting the 3 rd arbitration frame when the received N th arbitration frame has lower highest priority than the highest priority stored by the station. In other words, the communication device 11 transmits the 3 rd arbitration frame when the received highest priority is lower than the saved highest priority. The relay stage number stored in the 3 rd arbitration frame is the relay stage number of the port which receives the smallest relay stage number among the ports which receive the N th arbitration frame stored with the highest priority. Therefore, the relay stage number stored in the 3 rd arbitration frame is the smallest relay stage number among the relay stage numbers included in the N th arbitration frame stored with the highest priority.

If the communication device 11 receives the nth arbitration frame, the control section 52 extracts data from the received nth arbitration frame. Upon receiving the 1 st or 3 rd arbitration frame, the control unit 52 extracts the own station priority, the highest priority, the transmission time, and the relay order. Further, upon receiving the 2 nd arbitration frame, the control unit 52 extracts the highest priority, the transmission time, the number of relay stages, and the own station priority.

Then, the control unit 52 determines whether or not the difference between the extracted transmission time and the current time is within the specific time Tx. The current time may be a time when the communication unit 51 receives the nth arbitration frame, or a time when the control unit 52 performs the determination. When the difference between the transmission time and the current time is longer than the specific time Tx, the control unit 52 resets the top priority and the number of relay stages stored in the storage unit 53 to the values at the start. Thus, when the communication device 11 does not receive data from the N/W-most-priority station for a period longer than the predetermined time Tx, it deletes the old data of the network configuration.

On the other hand, when the difference between the transmission time and the current time is equal to or less than the specific time Tx, the communication device 11 transmits the 2 nd arbitration frame or the 3 rd arbitration frame to the nearest communication devices 12 and 13 in the loop in a cycle C1 shorter than the specific time Tx according to the processing in steps S110 to S155 described below.

In step S110, the control section 52 determines whether or not the nth arbitration frame is received from a plurality of different ports. The control unit 52 here determines whether or not the nth arbitration frame is received from the ports P11a, P11 b.

When the communication device 11 receives the nth arbitration frame from 1 port, that is, when No in step S110, the control unit 52 compares the highest priority in the received nth arbitration frame with the highest priority stored in the storage unit 53 of the communication device 11 as the own station. Then, in step S130, the control unit 52 determines whether or not the received highest priority is higher than the stored highest priority.

When the highest priority in the received nth arbitration frame is lower than the stored highest priority, that is, when No in step S130, the control unit 52 does not change the data stored in the storage unit 53 in step S140. Then, in step S145, the communication unit 51 transmits the 3 rd arbitration frame from the port that received the N th arbitration frame. In this way, when the received highest priority is lower than the stored highest priority, the communication device 11 does not change the data stored in the local station. On this basis, the communication device 11 broadcasts a 3 rd arbitration frame from the port that received the N th arbitration frame.

As described above, the 3 rd arbitration frame includes 4 pieces of data of the own station priority, the highest priority, the transmission time, and the relay order. The number of relay stages included in the 3 rd arbitration frame is the number of stages with the smallest number of relay stages among the ports that have received the arbitration frame stored with the highest priority. This prevents the communication device 11 from using a communication path having a large number of relay stages. Consider a case where 5 communication devices are arranged in a loop. If the 1 st communication device of the 5 is not the N/W most priority station, there is a case where the 1 st communication device receives the arbitration frame transmitted from the clockwise direction and the arbitration frame transmitted from the counterclockwise direction of the loop. It is assumed that the clockwise direction of the loop is the direction of the turn-around within the loop, and the counterclockwise direction of the loop is the direction of the turn-around within the loop, as viewed from the communication device 11. In this case, the number of relay stages of the arbitration frame transmitted from the counterclockwise direction in the loop is smaller than that of the arbitration frame transmitted from the clockwise direction in the loop. Therefore, the communication device 11 includes the minimum number of relay stages in the 3 rd arbitration frame, and broadcasts the 3 rd arbitration frame.

When the highest priority in the received nth arbitration frame is higher than the stored highest priority, that is, when Yes in step S130, the data stored in the storage unit 53 is changed to generate the 2 nd arbitration frame. As described above, the 2 nd arbitration frame includes 4 pieces of data, which are the highest priority, the transmission time, the relay order, and the own station priority.

In step S150, the control unit 52 changes the top priority, the transmission time, and the relay order stored in the storage unit 53. At this time, the control unit 52 changes the highest priority and the transmission time stored in the storage unit 53 to the highest priority and the transmission time in the received nth arbitration frame. The control unit 52 changes the number of relay stages of the port that receives the nth arbitration frame to the number of relay stages + 1. In this way, the relay stage number is increased by 1 stage every time the nth arbitration frame passes through the communication device 10X. In step S155, the communication unit 51 broadcasts and transmits the 2 nd arbitration frame storing the changed data from the ports other than the port that received the N th arbitration frame.

In step S110, when the communication device 11 receives the nth arbitration frame from the plurality of different ports, that is, when Yes in step S110, the control unit 52 compares the highest priority in the received nth arbitration frame with the highest priority stored in the storage unit 53 of the communication device 11 as the own station. Then, in step S120, the control unit 52 determines whether the received highest priority is the same as the stored highest priority.

When the highest priority in the received nth arbitration frame is different from the stored highest priority, that is, when No in step S120, the control unit 52 executes the processing of steps S130 to S155.

On the other hand, when the highest priority in the received nth arbitration frame is the same as the stored highest priority, that is, when Yes is obtained in step S120, the control unit 52 determines that the own station is present on the loop. That is, when the top priorities received from the plurality of different ports match the stored top priorities, the control unit 52 determines that the communication device 11 is present on the loop.

In the network management system 101, each communication device 10X executes the processing of steps S100 to S155 described above 1 time or more. Thus, each communication device 10X updates the highest priority, transmission time, and relay order stored in its own station.

Thereafter, if the communication device 11 has a port of a path that relays the most stations in the loop from the communication device 10X having the highest priority through the processing of steps S160 to S250 shown in fig. 4, the port is closed. Thus, the communication device 10X of the path of the station having the most number of relays from the N/W most-preferred station closes the port connected to the path of the station having the most number of relays. As a result, the network management system 101 can set a communication path that can eliminate a loop and prevent the same frame from being received a plurality of times by 1 communication apparatus 11. Hereinafter, the processing of steps S160 to S250 is explained.

In step S160, the control unit 52 determines whether or not the relay stage number stored in the storage unit 53 is a non-set value. The number of relay stages stored in the storage unit 53 is the number of relay stages of the reception port. Therefore, the initial value of the number of relay stages stored in the storage unit 53 is a non-set value, and is updated by the processing of step S150.

When the stored number of relay stages is not a set value, that is, when Yes is obtained in step S160, the control unit 52 changes the stored number of relay stages to a value obtained by adding 1 stage to the received number of relay stages in step S180. In other words, the control unit 52 sets the received relay order number + 1as a new relay order number. The storage unit 53 stores the changed relay order number.

When the number of relay stages to be stored is set to an arbitrary set value, that is, No in step S160, the control unit 52 determines whether or not the number of relay stages in the received nth arbitration frame is smaller than the number of relay stages to be stored in step S170. An example of a case where the number of relay stages in the received nth arbitration frame is smaller than the number of relay stages stored is a case where a communication path shorter than the current state is found by the received nth arbitration frame.

If the number of relay stages in the received nth arbitration frame is smaller than the number of relay stages stored, that is, if Yes in step S170, the control unit 52 changes the number of relay stages stored to a value obtained by adding 1 stage to the number of relay stages received in step S180. After the process of step S180, the control unit 52 executes the process of step S190, which will be described later.

After steps S160 to S180, the communication device 11 compares the number of relay stages of each port. At this time, the controller 52 compares the relay stage numbers of the ports P11a and P11b with the received relay stage numbers.

Specifically, when the number of relay stages stored is equal to or smaller than the number of relay stages in the received nth arbitration frame, that is, when No in step S170, the control unit 52 determines whether or not there is a port having the same number of relay stages among the ports provided in the communication device 11 in step S190. After the process of step S180, in step S190, the control unit 52 determines whether or not there is a port having the same relay order number among the ports provided in the communication device 11.

When there are ports having the same relay number, that is, Yes in step S190, among the ports provided in the communication device 11, the control unit 52 closes, in step S220, ports other than the port having the smallest port number among the ports having the same relay number. In other words, the control unit 52 opens only the port with the smallest port number among the ports having the same relay order number. Thus, the closed port can only transceive the nth arbitration frame and frames that do not circulate in the loop. An example of a case where there are ports having the same relay order number is a case where the own station is the communication device 10X that relays the most from the N/W most superior station. Further, the control unit 52 may close and open any port among the ports having the same relay order number, but the number of the opened ports is 1.

If there is No port having the same relay order number among the ports provided in the communication device 11, that is, if No in step S190, the control unit 52 determines whether or not there is a port having a relay order number 1 higher than that of the other ports in step S200.

When there is No port having a relay stage number that is 1 stage greater than that of the other ports, that is, No in step S200, in step S210, the communication unit 51 broadcasts and transmits the 2 nd arbitration frame in which the changed data is stored, from ports other than the receiving port, which is a port having a relay stage number greater than or equal to 2 stages greater than that of the other ports. An example of a case where there are ports having a number of relay stages greater than or equal to 2 stages than those of other ports is a case where the communication device 10X of a station having the most relays from the N/W most superior station is not determined.

On the other hand, when there is a port having only 1 stage higher in the number of relay stages than the other ports, that is, when Yes is obtained in step S200, the control unit 52 compares the own station priority stored in the received nth arbitration frame with the own station priority stored in the storage unit 53. Thus, the control unit 52 compares the own-station priority stored in the communication device 10X of the transmission source with the own-station priority stored in the communication device 11 as the own station. There is an example in which the number of relay stages is 1 stage more than that of other ports, and this is a case in which one of the own station and the nearest other station in the loop is the communication device 10X of the station having the most relays from the N/W most advanced station.

In step S230, the control unit 52 determines whether or not the received own station priority is lower than the stored own station priority. If the own station priority stored in the received nth arbitration frame is lower than the own station priority stored therein, that is, if Yes in step S230, the control unit 52 closes the port having only 1 stage higher in the number of relay stages than the other ports in step S240. In this way, when there is a port having only 1 stage higher in the relay number than other ports and the own station priority of the own station is higher than the own station priority of the other station closest to the ring, the control unit 52 closes the port having only 1 stage higher in the relay number than other ports.

On the other hand, in the case where the own station priority stored in the received nth arbitration frame is higher than or equal to the own station priority stored, that is, in the case of No in step S230, in step S250, the control section 52 opens the port whose relay stage number is 1 stage greater than that of the other ports in the case where the port is closed. When only the port having 1 stage more than the other ports is opened, the control unit 52 does not perform opening and closing of the port.

In this way, by the processing in steps S160 to S250, the communication device 10X on the path of the station having the most relay from the N/W most prior station closes the port connected to the path of the station having the most relay. When the number of communication apparatuses 10X connected in a ring is even, ports having the same relay order number are generated in any communication apparatus 10X in the network management system 101. On the other hand, when the number of communication apparatuses 10X connected in a ring is odd, a port having only 1 stage more relay stages than the other ports is generated in any communication apparatus 10X in the network management system 101. The communication device 10X that generates ports having the same relay order closes any port. When a port having a relay stage number 1 higher than that of the other port is generated, the communication device 10X or the communication device 10X nearest to the loop closes the port having the relay stage number 1 higher than that of the other port.

The port closed in the processing of step S220 or step S240 is automatically opened by the control unit 52 when the closing condition is not satisfied due to a change in the communication path or due to a time-lapse reset. Thus, the opened port can transmit and receive all frames.

In the communication device 10X, a station that has not received the nth arbitration frame having the highest priority higher than the priority of the station itself within the specific time Tx determines that the station itself is the station having the highest priority on the network and is the only N/W management station that is responsible for network management.

Fig. 5 is a diagram showing a state in which a loop is closed in the network management system according to embodiment 1. Here, a case where the network management system 101 shown in fig. 2 closes the loop is explained.

In fig. 5, the local station priorities of the communication devices 11 to 14 are represented by [1] to [4 ]. The numerical value indicating the priority of the local station is such that the smaller the numerical value, the higher the priority. Here, the own-station priority of the communication device 11 is set to [1], the own-station priority of the communication device 12 is set to [2], the own-station priority of the communication device 13 is set to [3], and the own-station priority of the communication device 14 is set to [4 ].

In this case, if the communication devices 11 to 14 in the network management system 101 execute the above-described processing of steps S100 to S250, the communication devices 12 to 14 recognize the relay order number in the following manner.

That is, the communication apparatus 12 recognizes that the relay stage number of the port P12a that receives the nth arbitration frame from the communication apparatus 11 is 1 stage. In addition, the communication device 13 recognizes that the relay stage number of the port P13a that receives the nth arbitration frame from the communication device 11 is 1 stage. In addition, the communication apparatus 14 recognizes that the relay order number of the port P14b that receives the nth arbitration frame from the communication apparatus 12 is 2 levels, and recognizes that the relay order number of the port P14a that receives the nth arbitration frame from the communication apparatus 13 is 2 levels. In fig. 5, <1> indicates that the number of relay stages is 1 stage, and <2> indicates that the number of relay stages is 2 stages.

Since the communication device 11 is the N/W most prioritized station and is the N/W management station, the communication device 14 is a station of a communication path that relays the most stations from the N/W management station. In this case, the communication device 14 closes any port. Since the number of communication apparatuses 10X connected in a ring in the network management system 101 is an even number, ports other than the port with the smallest port number among the ports having the same relay order number are closed as described in step S220. In the case where the port number of the port P14b is smaller than the port number of the port P14a, the communication device 14 closes the port P14 b.

In the network management system 101, if the communication device 14 closes the port P14b, the communication device 14 does not transmit but discards even if it receives the nth arbitration frame. Specifically, if the communication device 14 receives the nth arbitration frame transmitted from the communication device 12 or the communication device 13, the received nth arbitration frame is discarded.

The communication device 11 broadcasts and transmits the 1 st arbitration frame from all ports also in the cycle C1 after becoming the N/W management station. Thereby, the communication devices 12, 13 transmit the 2 nd or 3 rd arbitration frame to the communication device 14. Then, the communication device 14 receives the 2 nd or 3 rd arbitration frame and discards it.

In the network management system 101 in such a state, there are cases where a communication path is changed, a new communication device 10X is connected, or a communication device 10X higher than the communication device 11 as the N/W management station is connected. In this case, if the condition for closing the port P14b or the condition for the communication device 11 to become the N/W management station is not satisfied, the network management system 101 resets the settings of the communication path and the N/W management station, and executes the processing of steps S100 to S250 1 or more times. Thus, any communication device 10X becomes a new N/W management station, and any port of any communication device 10X is closed.

The configuration of the network management system is not limited to the configuration having 1 loop as in the network management system 101 shown in fig. 2, and may be a configuration having a plurality of loops.

Fig. 6 is a diagram showing another example of the configuration of the network management system according to embodiment 1. Here, a case where the network management system 102 includes 6 communication devices 10X and 2 HUBs 31 and 32 will be described. In FIG. 6, communication devices 21 to 26 are communication devices 10X. Each of the communication devices 21 to 26 has the same function as the communication device 10X described above. Although the case where the devices having different communication standards from the communication devices 21 to 26 are the HUBs 31 and 32 has been described here, the devices having different communication standards from the communication devices 21 to 26 may be devices other than the HUBs 31 and 32.

In the network management system 102, the communication devices 21 to 26 and the HUBs 31 and 32 are connected in a ring shape. Specifically, the communication device 21 is connected to the HUB31, and the HUB31 is connected to the communication device 22. The communication device 22 is connected to the communication device 24, and the communication device 24 is connected to the communication device 25. The communication device 25 is connected to the communication device 26, and the communication device 26 is connected to the HUB 32. The HUB32 is connected to the communication device 23, and the communication device 23 is connected to the communication device 21. Furthermore, HUB32 is connected to HUB 31.

Thus, the network management system 102 has a 1 st loop, a 2 nd loop, and a 3 rd loop. The 1 st loop is a loop in which the communication device 21, HUB31, communication device 22, communication device 24, communication device 25, communication device 26, HUB32, and communication device 23 are connected in a ring shape. The 2 nd loop is a loop in which the communication device 21, HUB31, HUB32, and communication device 23 are connected in a ring shape. The 3 rd loop is a loop in which the HUB31, the communication device 22, the communication device 24, the communication device 25, the communication device 26, and the HUB32 are connected in a ring shape.

The communication device 21 includes ports P21a and P21b, and the communication device 22 includes ports P22a and P22 b. The communication device 23 includes ports P23a and P23b, and the communication device 24 includes ports P24a and P24 b. The communication device 25 includes ports P25a and P25b, and the communication device 26 includes ports P26a and P26 b.

Further, the port P21b is connected to the HUB31, and the HUB31 is connected to the port P22 a. Further, the port P22b is connected to the port P24b, and the port P24a is connected to the port P25 a. Further, the port P25b is connected to the port P26b, and the port P26a is connected to the HUB 32. HUB32 is connected to port P23a, and port P23b is connected to port P21 a.

In the network management system 102 having such a configuration, the communication devices 21 to 26 perform the same operations as those of the communication device 11 described above. Thus, the network management system 102 performs setting of a communication path in which a loop is closed and arbitration of the N/W management station.

Fig. 7 is a diagram showing a state in which a loop is closed in the network management system having another configuration according to embodiment 1. Here, a case where the network management system 102 shown in fig. 6 closes the loop is explained.

In fig. 7, the own-site priority of each site is represented by [1] to [6 ]. Here, the communication devices 21 to 26 are set with [1] to [6] of the own station priority, respectively. In this case, if the communication devices 21 to 26 in the network management system 102 perform the above-described processing of steps S100 to S250, the communication devices 22 to 26 recognize the relay order number in the following manner.

That is, the communication device 22 recognizes that the relay stage number of the port P22a that receives the nth arbitration frame from the communication device 21 is 1 stage. In addition, the communication apparatus 24 recognizes that the relay order number of the port P24b that receives the nth arbitration frame from the communication apparatus 22 is 2 levels, and recognizes that the relay order number of the port P24a that receives the nth arbitration frame from the communication apparatus 25 is 3 levels. In addition, the communication device 25 recognizes that the relay stage number of the port P25a that receives the nth arbitration frame from the communication device 24 is 3 stages.

In addition, the communication device 23 recognizes that the relay stage number of the port P23b that receives the nth arbitration frame from the communication device 21 is the 1-stage condition. The HUB31, if receiving the nth arbitration frame from the communication device 21, relays the nth arbitration frame to the communication device 22 as well as the HUB 32. HUB32 relays the nth arbitration frame from HUB31 to both communication devices 23, 26.

The port P23a of the communication device 23 receives the nth arbitration frame from the communication device 21 transmitted via the HUBs 31, 32. Also, the communication device 23 recognizes that the relay stage number of the port P23a that receives the nth arbitration frame from the HUB32 is 1 stage.

In addition, port P26a of the communication device 26 receives the nth arbitration frame from the HUB 32. The port P26a of the communication device 26 and the port P21a of the communication device 21 are connected via the communication device 23 and the HUB 32. Therefore, in this communication path, the number of relay stages of the port P26a is 2. However, the port P26a of the communication device 26 and the port P21b of the communication device 21 are also connected via the HUBs 31, 32. Therefore, in this communication path, the number of relay stages of the port P26a is 1. In this case, the communication device 26 recognizes that the relay stage number of the port P26a that receives the nth arbitration frame from the HUB32 is 1 stage.

In addition, the communication device 25 recognizes that the relay stage number of the port P25b that receives the nth arbitration frame from the communication device 26 is 2 stages. In fig. 7, <1> indicates that the number of relay stages is 1 stage, <2> indicates that the number of relay stages is 2 stages, and <3> indicates that the number of relay stages is 3 stages.

The communication device 21 serves as an N/W management station. In the 1 st loop, the communication device 25 is a station of a path that relays the most station from the communication device 21 that is the most advanced station in N/W. In the 2 nd loop, the communication device 23 is a station of a path that relays the most station from the communication device 21 that is the most advanced station in N/W.

Thereby, the communication device 25 and the communication device 23 close any port. Here loop 1 contains 6 communication means 21, 22, 24, 25, 26, 23. Therefore, as described in step S220, the communication device 25 closes the ports other than the port with the smallest port number among the ports having the same relay number. In the case where the port number of the port P25b is smaller than the port number of the port P25a, the communication device 25 closes the port P25 a.

In addition, the 2 nd loop includes 2 communication devices 21 and 23. Therefore, as described in step S220, the communication device 23 closes the ports other than the port with the smallest port number among the ports having the same relay number. In the case where the port number of the port P23a is smaller than the port number of the port P23b, the communication device 23 closes the port P23 b. In addition, closing port P25a through communication device 25 also eliminates loop 3.

AS one of standards for specifying a protocol for setting a communication path, there is ieee (institute of electrical and Electronics engineers)802.1 AS. In ieee802.1as, a protocol for arbitrating a path setting and an N/W management station in a network between communication apparatuses nearest to each other in a loop is defined. In this protocol, the HUB as a relay device needs to interpret ieee802.1as. Therefore, communication processing within the communication network is complicated. On the other hand, the network management systems 101, 102 broadcast-transmit the nth arbitration frame between the communication apparatuses 10X that are closest to each other within the loop, and the received nth arbitration frame is not forwarded to the other communication apparatuses 10X. Therefore, since the HUBs 31, 32 as relay devices may not interpret the communication, the path setting of the network and the arbitration of the N/W management station can be easily realized.

According to embodiment 1, since the network management systems 101 and 102 broadcast and transmit the nth arbitration frame between the communication apparatuses 10X that are closest to each other within the loop, even when a plurality of loops are connected via the HUBs 31 and 32, each loop can be closed. This prevents unnecessary data frames from continuing around the loop, and thus avoids the communication band in the loop from being compressed.

Further, since the network management systems 101 and 102 close the ports of the paths of the stations that have the most number of relays from the N/W most-preferred station, the transmission delay from the N/W most-preferred station can be minimized. As a result, the communication time in the network including the loop can be shortened.

Further, since the network management systems 101 and 102 close the ports of the paths of the stations that have the most number of relays from the N/W most-priority station, when the N/W management station and the time distribution station that performs time synchronization are the same station, the accuracy of time synchronization in which the transmission delay causes an error can be improved.

Further, since the network management systems 101 and 102 store data at the transmission time in the nth arbitration frame, it is possible to eliminate a loop while suppressing data of ports held by each station.

Embodiment mode 2

Next, embodiment 2 of the present invention will be described with reference to fig. 8 to 10. In embodiment 2, each station stores the N/W most-preferred station and the number of relay stages for each port, thereby suppressing the data amount of an M-th arbitration frame to be described later for setting a communication path.

The network management systems 101 and 102 according to embodiment 2 have the same configuration as the network management systems 101 and 102 according to embodiment 1. The communication device 10X according to embodiment 2 includes a communication unit 51, a control unit 52, and a storage unit 53, as in the communication device 10X according to embodiment 1.

Examples of the data stored in the storage unit 53 are data set for each communication device 10X and data set for each port provided in the communication device 10X. In embodiment 2, the data set for each communication device 10X is the own-station priority. The data set for each port is 4 pieces of data including the highest priority, the number of relay stages, the port number, and the port type.

The port category is any of "priority", "standard", "off", and "no category". The "priority" port is the port on the N/W most priority site side. Each site other than the N/W most preferred site has 1 "preferred" port. The "standard" ports are all ports except "off" and "none category" in the N/W most preferred site. The "standard" ports are all ports except for "priority", "off", and "none kind" in the station other than the N/W most priority station. The "closed" port is a port that closes a path when a loop is formed. A "non-typed" port is an unconnected port. The "non-generic" port becomes a "standard" port after connection. In the following description, a "priority" port is referred to as a priority port, a "standard" port is referred to as a standard port, and a "closed" port is referred to as a closed port.

The priority, the number of hops, and the port number set for each port are the same data as the priority, the number of hops, and the port number described in embodiment 1. In embodiment 2, the communication device 10X manages the highest priority, the number of relay stages, and the port number for each port.

In the network management systems 101 and 102, the 4 th to 6 th arbitration frames are transmitted and received between the communication apparatuses 10X that are closest to each other in the loop. The 4 th to 6 th arbitration frames are examples of arbitration frames. The 4 th arbitration frame is an arbitration frame broadcast-transmitted to the other communication device 10X closest to the communication device 10X in the loop when the communication device 10X starts setting the communication path. In addition, the 5 th and 6 th arbitration frames are arbitration frames broadcast-transmitted by the communication apparatus 10X that has received any of the 4 th to 6 th arbitration frames in correspondence with the contents of the received 4 th to 6 th arbitration frames. Therefore, the communication device 10X transmits the 4 th arbitration frame and receives any of the 4 th to 6 th arbitration frames if the setting of the communication path is started. Also, the communication device 10X transmits the 5 th or 6 th arbitration frame if receiving any of the 4 th to 6 th arbitration frames. In the following description, any one of the 4 th to 6 th arbitration frames is referred to as an mth arbitration frame.

Here, the 4 th to 6 th arbitration frames are explained.

(4 th arbitration frame)

The 4 th arbitration frame stores the following 3 data.

Priority of own site

Degree of optimality

Number of relay stages

The data stored in the 4 th arbitration frame is an initial value set in the communication device 10X.

(arbitration frame 5)

The 5 th arbitration frame stores the following 3 data.

Priority of own site

Degree of optimality

Number of relay stages

An example of the highest priority stored in the 5 th arbitration frame is the highest priority set for the port. An example of the number of relay stages stored in the 5 th arbitration frame is the number of relay stages set for the port.

(arbitration frame 6)

The 6 th arbitration frame stores the following 3 data.

Priority of own site

Degree of optimality

Number of relay stages

And transmitting the 6 th arbitration frame when the port with the highest priority is at the station compared with the port with the highest priority. The highest priority stored in the 6 th arbitration frame is the highest priority among the priorities set to the ports of the station. The relay stage number stored in the 6 th arbitration frame is the relay stage number set for the port set with the highest priority.

Fig. 8 is a flowchart showing a procedure of transmitting and receiving an arbitration frame according to embodiment 2. Fig. 9 is a flowchart showing a procedure of the port setting processing according to embodiment 2. Fig. 8 and 9 illustrate a communication process of the communication device 10X disposed in the network management systems 101 and 102. Since the communication devices 11 to 14, 21 to 26 execute the same processing, a communication processing procedure of the communication device 11 provided in the network management system 101 will be described here. Among the processes in fig. 8 and 9, the same processes as those described in fig. 3 and 4 will not be described in duplicate.

When the setting of the communication path is started, all the communication devices 11 to 14 are N/W most-priority stations. When the setting of the communication path is started, all the communication apparatuses 11 to 14 as the N/W most-priority stations broadcast and transmit the 4 th arbitration frame in which the priority, the most-priority, and the relay order of the station are stored to the other communication apparatuses 10X in the network management system 101. The communication devices 11 to 14 periodically broadcast and transmit the 4 th arbitration frame from all the standard ports at a cycle C1 shorter than the bit time Tx. The communication devices 11 to 14 store the 4 th arbitration frame, and the relay stage number is 0.

Since the communication devices 11 to 14 perform the same processing, a communication processing procedure in the communication device 11 is explained here. In step S300, if the communication device 11 receives the mth arbitration frame from the communication devices 12 and 13, the control unit 52 extracts the own station priority, the highest priority, and the relay order from the received mth arbitration frame.

Then, the control unit 52 compares the highest priority stored in the received mth arbitration frame with the highest priority of the reception port. In step S310, the control unit 52 determines whether the highest priority in the received mth arbitration frame is the same as the highest priority of the reception port stored in the storage unit 53.

When the received top priority is different from the stored top priority, that is, No in step S310, the control unit 52 determines whether or not the received top priority is higher than the stored top priority in step S320.

When the received highest priority is lower than the stored highest priority of the receiving port, that is, No in step S320, the control unit 52 determines whether or not the port type of the receiving port is a priority port in step S330.

When the stored port type is not the priority port, that is, when No is obtained in step S330, the control unit 52 does not change the data stored in the storage unit 53 and the communication unit 51 broadcasts and transmits the 5 th arbitration frame from the port that received the M-th arbitration frame in step S340. By the transmission of the 5 th arbitration frame, the communication device 11 notifies the station that has transmitted the M-th arbitration frame that it is not possible to become the N/W-most-preferred station. As described above, the 5 th arbitration frame includes 3 pieces of data, which are the priority of the station, the highest priority of the receiving port, and the relay order of the receiving port.

On the other hand, when the port type to be saved is a priority port, that is, when Yes is obtained in step S330, there is a possibility that the communication path is changed or the N/W-most priority station does not exist. Therefore, in step S350, the control unit 52 resets the top priorities, the relay numbers, and the port types of all the ports stored in the station to the values at the start, and the communication unit 51 transmits the 4 th arbitration frame from all the ports.

When the received highest priority is higher than the stored highest priority of the receiving port, that is, Yes in step S320, the control unit 52 changes the highest priority, the number of relay stages, and the port type set to the receiving port in step S390.

Specifically, the control unit 52 changes the highest priority of the receiving port to the received highest priority, changes the relay order of the receiving port to the received relay order +1, and changes the port type to the priority port. Then, the communication device 11 executes the processing of step S400 described later.

When the received highest priority is the same as the stored highest priority of the receiving port, that is, Yes in step S310, the control unit 52 determines in step S360 whether or not the value obtained by adding 1 stage to the number of relay stages stored in the received mth arbitration frame is smaller than the number of relay stages set in the receiving port.

If the number of received relay stages added with 1 stage is smaller than the number of relay stages of the receiving port, that is, if Yes in step S360, the control unit 52 changes the number of relay stages of the receiving port in step S380. Specifically, the control unit 52 changes the number of relay stages of the reception port to the number of relay stages +1 received. In other words, when the number of relay stages of the reception port can be set to a value smaller than the current setting, the control unit 52 changes the number of relay stages of the reception port to a value obtained by adding 1 stage to the number of relay stages received. After that, the communication device 11 executes the process of step S400 described later.

On the other hand, when the number of relay stages obtained by adding 1 stage to the number of relay stages received is greater than or equal to the number of relay stages of the receiving port, that is, when No is obtained in step S360, the communication unit 51 broadcasts and transmits the 5 th arbitration frame from all the standard ports in step S370. The highest priority stored in the 5 th arbitration frame is the highest priority set for the receiving port, and the relay stage number stored in the 5 th arbitration frame is the relay stage number set for the receiving port.

The communication device 11 executes the process of step S400 after step S380 or step S390.

In the network management system 101, each communication device 10X executes the processing of the above-described steps S300 to S390 1 time or more. Thus, each communication device 10X updates the highest priority, port type, and relay order stored in its own station.

The control unit 52 compares the highest priority of the receiving port with the highest priorities of the ports other than the receiving port in the station, and determines whether or not the highest priority of the receiving port is the same as the highest priorities of the other ports in step S400. When the highest priority of the receiving port is different from the highest priority of the other port, that is, No in step S400, the control unit 52 determines whether or not the highest priority of the receiving port is higher than the highest priority of the other port in step S410.

When the highest priority of the receiving port is higher than the highest priorities of the other ports, that is, Yes in step S410, the control unit 52 changes the port type of the port to which the highest priority lower than the highest priority of the receiving port is set to the standard port in step S420, and the communication unit 51 transmits the 5 th arbitration frame from all the standard ports.

In this way, when there is a port having a lower highest priority than the receiving port, the communication unit 51 changes the port having the lower highest priority to the standard port and transmits the 5 th arbitration frame from all the standard ports. Here, the 5 th arbitration frame includes the station priority, the highest priority of the reception port, and the relay order of the reception port.

When the highest priority of the receiving port is lower than the highest priority of the other ports, that is, No in step S410, the control unit 52 changes the port type of the receiving port to the standard port in step S430, and the communication unit 51 transmits the 6 th arbitration frame from the receiving port. The control unit 52 does not change the highest priority and the number of relay stages of the reception port.

In this way, when there is a port having the highest priority higher than that of the receiving port, the communication unit 51 changes the receiving port to the standard port and transmits the 6 th arbitration frame from the receiving port. Here, the 6 th arbitration frame includes the priority of the station itself, the highest priority among the priorities stored in the ports, and the number of relay stages set in the port to which the highest priority is set.

In the case where the highest priority of the reception port and the highest priority of the other ports are different, that is, in the case of No in step S400, the communication apparatus 11 executes the processing of steps S410 to S430 and the processing of step S400 at a time.

When the highest priority of the receiving port is the same as the highest priority of the other ports, that is, when Yes is obtained in step S400, the control unit 52 determines that the station is present on the loop and determines whether or not a port closed to cancel the loop is present. Specifically, the control unit 52 compares the number of relay stages between ports having the highest priority.

In step S440, the control unit 52 determines whether or not there is a port having the same highest priority as the port having the same relay order. If there is a port having the highest priority and the number of relay stages that match each other, that is, if Yes in step S440, the control unit 52 closes the ports other than the port having the lowest port number among the ports having the highest priority and the number of relay stages that match each other in step S470. In addition, if the ports have the highest priority and the number of relay stages matching each other, the control unit 52 may close any port and open any port, but the number of open ports is 1.

If there is No port having the highest priority and the number of relay stages that match, that is, if No in step S440, the communication device 11 determines whether there is a port having the highest priority and the number of relay stages that is 1 stage higher than the other ports in step S450.

If there is No port having a relay stage number 1 higher than that of the other ports among the ports having the same highest priority, that is, if No in step S450, the control unit 52 changes the port having the same highest priority and having a relay stage number 2 or more higher than that of the other ports to the standard port in step S460. Then, in step S460, the control unit 52 stores the 6 th arbitration frame with the smallest relay stage number among the relay stage numbers of the ports with the highest priority matching, and the communication unit 51 broadcasts and transmits the 6 th arbitration frame. In this case, the communication section 51 broadcasts and transmits the 6 th arbitration frame from the ports other than the receiving port.

On the other hand, when there is a port having only 1-stage higher relay order than the other ports among the ports having the same highest priority, that is, when Yes is obtained in step S450, the control unit 52 compares the own station priority stored in the received mth arbitration frame with the own station priority stored in the storage unit 53.

Then, in step S480, the control unit 52 determines whether or not the own station priority stored in the received mth arbitration frame is lower than the own station priority stored therein. If the own station priority stored in the M-th arbitration frame received is lower than the own station priority stored therein, that is, if No in step S480, the control unit 52 closes, in step S500, a port having only 1-stage higher relay stage number than the other ports among the ports having the same highest priority.

On the other hand, if the own port priority stored in the M-th arbitration frame received is higher than or equal to the own port priority stored, that is, if Yes in step S480, the control unit 52 changes the port to the standard port if, of the ports having the same highest priority, the port having only 1-stage higher relay order than the other ports is the closed port in step S490.

In this way, when the own station is a station on the communication path of the station which relays the most in the loop from the N/W most-preferred station, the control unit 52 closes the port connected to the communication path, thereby setting a communication path which prevents the same frame from being received a plurality of times by 1 station.

The port closed in the processing of step S470 or step S500 is automatically opened by the control unit 52 when the condition for closing is not satisfied due to a change in the communication path or a reset with the passage of time. Thus, the opened port can transmit and receive all frames. The number of relay stages is compared among ports having the same highest priority, and the port having the smallest number of relay stages is set as a priority port, and the port having the smallest number of relay stages is set as a standard port.

In the communication device 10X, a station that has not received the mth arbitration frame having the highest priority higher than the priority of the station itself within the specific time Tx determines that the station itself is the station having the highest priority on the network and is the only N/W management station that is responsible for network management.

In addition, when the priority port fails to receive a new mth arbitration frame after a specific time Tx has elapsed since the previous reception of the mth arbitration frame, a station that is not an N/W management station determines that the N/W management station is not present. Then, the station other than the N/W management station resets the top priorities, the relay numbers, and the port types of all the ports stored in the station to the values at the start, and then broadcasts and transmits the 4 th arbitration frame.

When a specific time Tx has elapsed since the last reception of the mth arbitration frame and a new mth arbitration frame cannot be received, the station that has set the closed port determines that the loop structure is cleared and changes the closed port to the standard port.

Note that the specific time Tx described in embodiment 1 and the specific time Tx described in embodiment 2 may be different from each other or the same.

As described above, according to embodiment 2, since the network management systems 101 and 102 broadcast and transmit the mth arbitration frame between the communication apparatuses 10X that are closest to each other in the loop, the same effect as that of embodiment 1 can be obtained.

In the network management systems 101 and 102, since each station stores the N/W most-priority station and the number of relay stages for each port, it is possible to eliminate a loop while suppressing the data amount of the mth arbitration frame.

The hardware configuration of the control unit 52 will be described here, fig. 10 is a diagram showing an example of the hardware configuration of the control unit included in the communication device according to the embodiment, the control unit 52 of the communication device 10X can be realized by the control circuit 300 shown in fig. 10, that is, the processor 301 and the memory 302, and examples of the processor 301 are a CPU (also referred to as a Central processing unit, a processing device, an arithmetic device, a microprocessor, a microcomputer, a processor, a DSP) and an example of the system L SI (L area Integration) memory 302 are a ram (random Access memory) and a rom (read only memory).

The processor 301 reads and executes a program for executing the operation of the control unit 52 stored in the memory 302, thereby realizing the control unit 52. The program is also referred to as a program for causing a computer to execute the steps or method of the control unit 52. The memory 302 is also used as a temporary memory when the processor 301 executes various processes.

As such, the program executed by the processor 301 is a computer program product readable by a computer and having a Non-transitory (Non-transitory) recording medium, the computer program product including a plurality of instructions executable by the computer for performing data processing. The program executed by the processor 301 causes the computer to execute a plurality of instructions to perform data processing.

The control unit 52 may be implemented by dedicated hardware. The functions of the control unit 52 may be partially implemented by dedicated hardware, and partially implemented by software or firmware.

The configuration shown in the above embodiment is an example of the contents of the present invention, and may be combined with other known techniques, and some of the configurations may be omitted or modified within a range not departing from the gist of the present invention.

Description of the reference numerals

10X, 11 to 14, 21 to 26 communication devices, 51 communication parts, 52 control parts, 53 storage parts, 101 and 102 network management systems, P11a, P11b, P12a, P12b, P13a, P13b, P14a, P14b, P21a, P21b, P22a, P22b, P23a, P23b, P24a, P24b, P25a, P25b, P26a and P26b ports.

Claims (15)

1. A network management system, characterized in that,

the disclosed device is provided with:

a plurality of communication devices connected to form a 1 st loop in a communication network; and

a relay device that has a communication specification different from that of the communication device, is connected to the 1 st loop and the 2 nd loop in the communication network, and relays frames to the 1 st loop and the 2 nd loop,

the communication device has:

a control unit that performs a path determination for determining whether or not the own device is connected to a communication path of a communication device having the most number of relays from a priority device to the own device, the priority device being a communication device having the highest 1 st highest priority among device priorities set for each communication device in the communication network, based on a relay order of frames from the priority device to the own device;

a storage unit that stores a 2 nd highest priority, the 2 nd highest priority being a highest device priority identified by the own device among the device priorities; and

a communication unit which transmits a 1 st frame and receives a 2 nd frame via a port between the communication unit and another communication device closest to the communication unit in the 1 st loop,

the communication unit transmits the 1 st frame stored with the 2 nd highest priority to the other communication device, and receives the 2 nd frame stored with the 3 rd highest priority from the other communication device, the 3 rd highest priority being the highest device priority identified by the other communication device among the device priorities,

the control unit performs the path determination based on the number of relay stages of frames from the priority device to the own device, the 2 nd highest priority, and the 3 rd highest priority, and sets any one of the ports in the 1 st loop as an end of the communication network when determining that the own device is connected to a communication path of a communication device that has relayed most from the priority device,

the communication unit broadcasts the 1 st frame and does not forward the 2 nd frame to the other communication device even if the 2 nd frame is received,

and if the relay device receives the 2 nd frame, forwarding the 2 nd frame to the other communication devices.

2. The network management system of claim 1,

the device priority is set for each of the communication devices,

the relay order is set for each port of the communication device.

3. The network management system of claim 1,

the device priority is set for each port of the communication device,

the relay order is set for each port of the communication device.

4. The network management system of claim 1,

the control unit changes the value of the 2 nd highest priority to the value of the 3 rd highest priority when the 3 rd highest priority is higher than the 2 nd highest priority,

the communication unit transmits the 1 st frame storing the 2 nd highest priority with the changed value from a port different from the port on which the 3 rd highest priority is received.

5. The network management system according to any one of claims 1 to 4,

the relay order is stored in the 2 nd frame,

the control unit adds 1 level to the relay level number when the 3 rd highest priority is higher than the 2 nd highest priority,

the communication unit transmits the 1 st frame, in which the new relay stage number of the 1 st stage is added, from a port different from the port having received the 3 rd highest priority.

6. The network management system according to any one of claims 1 to 4,

in the case of the communication device in question,

the storage unit also stores the device priority of the present device,

when the communication unit does not receive the 3 rd highest priority higher than the device priority of the communication unit within a predetermined time, the communication unit becomes a network management station, and the control unit manages the communication network.

7. The network management system of claim 5,

in the case of the communication device in question,

the storage unit also stores the device priority of the present device,

when the communication unit does not receive the 3 rd highest priority higher than the device priority of the communication unit within a predetermined time, the communication unit becomes a network management station, and the control unit manages the communication network.

8. The network management system of claim 6,

the transmission time at which the priority device has transmitted the 1 st frame is stored in the 1 st frame and the 2 nd frame,

the control unit resets the 2 nd highest priority and the relay order number when a difference from the transmission time to a current time is longer than the specific time.

9. The network management system of claim 7,

the transmission time at which the priority device has transmitted the 1 st frame is stored in the 1 st frame and the 2 nd frame,

the control unit resets the 2 nd highest priority and the relay order number when a difference from the transmission time to a current time is longer than the specific time.

10. The network management system of claim 6,

the initial value of the 2 nd highest priority is the same as the device priority of the present device.

11. The network management system of claim 7,

the initial value of the 2 nd highest priority is the same as the device priority of the present device.

12. A method for network management, comprising:

a determination step of, in a communication network including a plurality of communication devices connected so as to form a 1 st loop and a relay device connected to the 1 st loop and the 2 nd loop and performing frame relay to the 1 st loop and the 2 nd loop, performing path determination based on a relay order number of frames from a priority device to the own device, the priority device being a communication device to which a highest 1 st highest priority is set among device priorities set for each communication device in the communication network, and determining whether or not the own device is connected to a communication path of a communication device having a largest number of relays from the priority device;

a storage step of storing, by the communication device, a 2 nd highest priority, the 2 nd highest priority being a highest device priority identified by the own device among the device priorities; and

a communication step in which the communication device transmits a 1 st frame and receives a 2 nd frame via a port with another communication device closest to the 1 st ring,

in the communication step, the communication apparatus transmits the 1 st frame, in which the 2 nd highest priority is stored, to the other communication apparatus, and the communication apparatus receives the 2 nd frame, in which the 3 rd highest priority is stored, from the other communication apparatus, the 3 rd highest priority being the highest apparatus priority identified by the other communication apparatus among the apparatus priorities,

in the determination step, the communication device performs the path determination based on the number of relay stages of frames from the priority device to the own device, the 2 nd highest priority, and the 3 rd highest priority, and sets any one of the ports in the 1 st loop as an end of the communication network when the own device is determined to be connected to a communication path of a communication device that has relayed the most from the priority device,

the communication device broadcasting the 1 st frame without forwarding the 2 nd frame to the other communication device even if the 2 nd frame is received,

and if the relay device receives the 2 nd frame, forwarding the 2 nd frame to the other communication devices.

13. The network management method according to claim 12,

the device priority is set for each port of the communication device,

the relay order is set for each port of the communication device.

14. The network management method according to claim 12,

further comprising a resetting step of resetting the 2 nd highest priority and the relay order number of all ports in the communication device when the 3 rd highest priority is lower than the 2 nd highest priority and when the port receiving the 3 rd highest priority is the port on the priority device side.

15. The network management method according to any one of claims 12 to 14,

when the transmission time at which the priority device has transmitted the 1 st frame is stored in the 1 st frame and the 2 nd frame,

the communication device resets the 2 nd highest priority and the relay order number when a difference from the transmission time to a current time is longer than a specific time.

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