JP6890334B2 - Communication equipment, control methods, and programs - Google Patents

Description

The present invention relates to communication devices, control methods, and programs.

There is a wireless mesh network (also simply referred to as a mesh network) in which a plurality of communication devices are connected to each other by wireless communication and multi-hop transfer of communication frames (data frames or simply frames) is performed. When the mesh network is connected to the wired backbone network, the terminal connected to the mesh network can communicate with the device connected to the backbone network via the mesh network.

In order to make the connection between the mesh network and the backbone network redundant, the mesh network and the backbone network are connected by a plurality of communication devices. In this case, it is necessary to prevent a loop from occurring in the communication path.

Conventionally, a technique of avoiding the occurrence of a loop in a mesh network and switching a communication path by using STP (Spanning Tree Protocol) has been disclosed (Patent Document 1).

International Publication No. 2015/04307

However, when the routing protocol used in the mesh network and the loop avoidance protocol such as STP are used together, the communication route cannot be switched appropriately when the route switching becomes necessary due to the occurrence of a failure of the communication device or the like. There is a problem that there are times.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a communication device or the like capable of appropriately switching communication paths in a mesh network.

In order to solve the above problems, the communication device according to one aspect of the present invention is one of a plurality of communication devices constituting a mesh network, and the mesh network is a communication device of the plurality of communication devices. It is communicably connected to the destination terminal via the wired interface provided by each of the two or more communication devices, and the wired interface provided by each of the two or more communication devices is dynamically driven by a protocol for avoiding a loop. Is set to either a communication permitted state or a communication prohibited state, and the one communication device includes a wireless interface for wireless communication with a source terminal and the wired interface among the plurality of communication devices. When the route control unit that manages the terminal information indicating the communication device connected to the destination terminal and the frame transmitted by the source terminal to the destination terminal are received by the wireless interface, they are received. The route control unit includes a transfer unit that transfers the frame to the communication device indicated in the terminal information in the mesh network, and the route control unit transfers the frame transferred by the transfer unit to the destination terminal. If it cannot be reached, the terminal information is deleted.

According to this, the communication device subsequently performs a process of generating terminal information necessary for transmitting a frame to the destination terminal by deleting the terminal information when the transferred frame cannot reach the destination terminal. You can create an opportunity. When the terminal information is deleted in this way, the communication device subsequently generates new terminal information and transfers the frame to the destination terminal using the generated new terminal information. The communication path for communication from within the mesh network to the destination terminal is a communication path that passes through a communication device that is in a communication permitted state among communication devices equipped with a wired interface, and the terminal information is terminal information consistent with the above communication path. It has become. At this time, if some factor occurs and the communication device in the communication permitted state transitions to the communication prohibited state by the processing of the loop avoidance protocol, communication to the destination terminal via the communication path becomes impossible. Therefore, if terminal information is newly generated when such a state transition occurs, the newly generated terminal information is a terminal that matches the communication path via the communication device that has newly transitioned to the communication permission state. It becomes information. As a result, the frame transmitted by the source terminal can reach the destination terminal according to the new communication path and terminal information. As described above, the communication device according to the present embodiment can appropriately switch the communication path in the mesh network.

Further, when the terminal information is deleted, the route control unit generates new terminal information by transmitting and receiving a search frame for searching the destination terminal by the wireless interface.

According to this, the communication device can transfer the frame toward the destination terminal by using the new terminal information generated by deleting the terminal information. Therefore, the communication device can appropriately switch the communication path in the mesh network.

Further, the route control unit cannot reach the destination terminal based on the communication device in which the wired interface is in the communication permitted state, among the two or more communication devices, becomes incommunicable state. In this case, the terminal information is deleted.

According to this, when the communication device connected to the wired network becomes incommunicable state, the communication device avoids the communication device in the incommunicable state and newly establishes a communication path to the destination terminal. To generate. In this way, the communication device can be appropriately switched to a new communication path that avoids the communication device that has become incommunicable.

Further, when the frame cannot reach the destination terminal based on the fact that the communication device that has become incommunicable state has become communicable among the two or more communication devices, the route control unit has a case. The terminal information is deleted.

According to this, when the communication device in the communication impossible state becomes communicable, the communication device newly generates a communication path to the destination terminal via the communication device in the communication enable state. To do. In this way, the communication device can be appropriately switched to a new communication path via the communication device that has become communicable.

Further, the route control unit further stores the route information in the mesh network that stores the next hop device in the communication path from the one communication device to the communication device shown in the terminal information. The transfer unit manages and transfers the received frame by transmitting it toward the next hop device on the communication path.

According to this, the communication device further uses the route information to transfer the frame in the mesh network. As a result, even when the communication device is not adjacent to the communication device shown in the terminal information, the frame can be transmitted to the destination obtained by using the route information.

Further, in the communication device, the protocol is STP (Spanning Tree Protocol), the communication permission state is the forwarding state specified by STP, and the communication prohibition state is the blocking state specified by STP. is there.

According to this, it is possible to appropriately switch the communication path in the mesh network while avoiding the occurrence of loops more easily by STP.

Further, the control method according to one aspect of the present invention is a communication device of one of a plurality of communication devices constituting a mesh network, and is a control method of a communication device provided with a wireless interface for wireless communication with a source terminal. The mesh network is communicably connected to a destination terminal via a wired interface included in each of two or more communication devices among the plurality of communication devices, and the mesh network is provided in each of the two or more communication devices. The wired interface is dynamically set to one of a state including a communication permitted state and a communication prohibited state by a protocol for avoiding a loop, and the control method is the wired interface among the plurality of communication devices. When a route control step that manages terminal information indicating a communication device connected to the destination terminal and a frame transmitted by the source terminal to the destination terminal are received by the wireless interface, it is received. In the route control step, the frame transferred in the transfer step is the destination terminal. If the terminal information cannot be reached, the terminal information is deleted.

According to this, the same effect as that of the above-mentioned communication device is obtained.

Further, the program according to one aspect of the present invention is a program for causing a computer to execute the above control method.

According to this, the same effect as that of the above-mentioned communication device is obtained.

The present invention can be realized not only as an apparatus, but also as a method in which the processing means constituting the apparatus is used as a step, as a program for causing a computer to execute those steps, or as a computer reading in which the program is recorded. It can also be realized as a possible recording medium such as a CD-ROM, or as information, data or a signal indicating the program. Then, those programs, information, data and signals may be distributed via a communication network such as the Internet.

According to the present invention, the communication device can appropriately switch the communication path in the mesh network.

FIG. 1 is a schematic diagram showing a configuration of a communication system according to an embodiment. FIG. 2 is a block diagram showing a configuration of a base station according to an embodiment. FIG. 3 is an explanatory diagram of a route table according to the embodiment. FIG. 4 is an explanatory diagram of a terminal table according to the embodiment. FIG. 5 is a flow chart showing the processing of the base station according to the embodiment. FIG. 6 is a sequence diagram showing normal processing in the communication system according to the embodiment. FIG. 7 is a sequence diagram showing processing when a failure occurs in the communication system according to the embodiment. FIG. 8 is a sequence diagram showing a process at the time of failure recovery in the communication system according to the embodiment. FIG. 9 is a schematic diagram showing a configuration of another form of the communication system according to the embodiment and a communication path in a normal state. FIG. 10 is a schematic diagram showing a communication path when a failure occurs in another form of the communication system according to the embodiment.

Hereinafter, embodiments will be specifically described with reference to the drawings.

Each of the embodiments described below shows a preferred specific example of the present invention. Numerical values, shapes, materials, components, arrangement positions and connection forms of components, steps, order of steps, etc. shown in the following embodiments are examples, and are not intended to limit the present invention. Further, among the components in the following embodiments, the components not described in the independent claims indicating the highest level concept of the present invention will be described as arbitrary components constituting the more preferable form. The same components may be designated by the same reference numerals and description thereof may be omitted.

(Embodiment)
In the present embodiment, a base station as a communication device for appropriately switching communication paths in a mesh network will be described.

FIG. 1 is a schematic diagram showing a configuration of a communication system 1 according to the present embodiment.

As shown in FIG. 1, the communication system 1 includes base stations M1, M2 and M3, and a hub 20. Communication system 1 is connected to terminals T1 and T2.

Base stations M1, M2, and M3 are communication devices that are base stations constituting a mesh network, and are also generally called mesh points (MP). The base stations M1, M2 and M3 may include at least a wireless IF (interface) and may further include a wired IF, as will be described later.

The base station M1 is wirelessly connected to the base stations M2 and M3 by a wireless IF. Further, the base station M1 is communicably connected to the terminal T1 by a wireless IF.

The base station M2 is wirelessly connected to the base station M1 by a wireless IF. Further, the base station M2 is connected to the terminal T2 via a hub 20 by a wired IF so as to be capable of wired communication.

The base station M3 is wirelessly connected to the base station M1 by a wireless IF. Further, the base station M2 is connected to the terminal T2 via a hub 20 by a wired IF so as to be capable of wired communication.

The hub 20 is a concentrator for a wired network, and is connected to base stations M2 and M3 and a terminal T2.

The terminal T1 is a terminal device capable of wireless communication, and is connected to the base station M1 so as to be capable of wireless communication.

The terminal T2 is a terminal device capable of wire communication, and is connected to the hub 20 so as to be capable of wire communication.

The base station M2 and the base station M3 communicate with each other by a protocol for avoiding a loop. Then, each of the wired IFs of the base station M2 and the base station M3 is dynamically set to one of a plurality of states including the communication permitted state and the communication prohibited state by the above protocol. An example of the above protocol is STP. In this case, the communication permitted state is the forwarding state specified by STP, and the communication prohibited state is the blocking state specified by STP. Although this case will be described below, RSTP (Rapid Spanning Tree Protocol) can also be adopted as another example.

Further, the base stations M1, M2 and M3 communicate with each other by the routing protocol of the mesh network, and the communication within the mesh network and the communication path of the communication between the terminals via the mesh network are constructed by this routing protocol. Maintained. As the routing protocol of the mesh network, for example, a routing protocol conforming to the IEEE802.11s standard can be adopted.

It is assumed that the terminal T1 transmits a frame toward the terminal T2 via the communication system 1. At this time, the terminal T1 is also referred to as a source terminal, and the terminal T2 is also referred to as a destination terminal.

The communication system 1 may have a first communication path via the base stations M1 and M2 and the hub 20, and a second communication path via the base stations M1 and M3 and the hub 20. Then, which of these communication paths the frame transmitted by the terminal T1 toward the terminal T2 flows is determined by the protocol for avoiding the loop and the routing protocol of the mesh network.

FIG. 2 is a block diagram showing a configuration of a base station M according to the present embodiment. The base station M corresponds to the base stations M1, M2 and M3 in FIG.

As shown in FIG. 2, the base station M includes a wired IF 11, wireless IFs 12 and 13, a transfer unit 14, an STP control unit 15, and a route control unit 16.

The wired IF 11 is a communication interface device connected to a wired network. The wired IF 11 follows, for example, the IEEE 802.3 standard. The wired IF11 is not an essential component. In the communication system 1 shown in FIG. 1, the base station M1 does not have to include the wired IF11. This is because the base station M1 is not connected to the wired network. On the other hand, the base stations M2 and M3 need to be provided with the wired IF11, and are connected to the hub 20 by the wired IF11.

The wireless IF 12 is a communication interface device that performs wireless communication. The wireless IF 12 establishes a wireless communication link with the wireless IF 12 of another base station M and performs wireless communication. The communication standard of the wireless IF12 is, for example, a wireless LAN conforming to IEEE802.11a, b, g, and n.

The wireless IF 13 is a communication interface device that performs wireless communication with a terminal. The wireless IF 13 establishes a wireless communication link with the terminal and performs wireless communication. The communication standard of the wireless IF13 is, for example, a wireless LAN conforming to IEEE802.11a, b, g, and n. Further, the wireless IF 13 is assumed to operate as an access point in, for example, an infrastructure mode, but the wireless IF 13 is not limited to this.

The wireless IF 12 and the wireless IF 13 may be realized as two wireless IFs that are logically different from each other by physically one wireless interface device.

The transfer unit 14 is a processing unit that transfers a frame between the wired IF 11 and the wireless IFs 12 and 13. When the transfer unit 14 receives a frame from any of the interfaces of the wired IF11 and the wireless IF12 and 13, the transfer unit 14 refers to the destination address of the received frame and transmits the frame to the destination address by an appropriate interface. Transfer with.

When the transfer unit 14 receives a frame from any of the above interfaces, the transfer unit 14 stores the source of the received frame in the transfer table (not shown) for a certain period of time. When the destination address of the received frame is a directly connected device, the interface to be output can be determined by referring to the transfer table. Further, when the destination address of the received frame is a device connected via another base station M, the transfer unit 14 displays the route table 17 and the terminal table 18 managed by the route control unit 16. The interface to be referred to and output the received frame can be determined from among the wired IF11, the wireless IF12 and 13. The method of determining the interface will be described later. The route table 17 is also referred to as route information, and the terminal table 18 is also referred to as terminal information.

If the interface determined by referring to the route table 17 and the terminal table 18 cannot transmit a frame, the transfer unit 14 may transmit an error frame to the source of the frame. As the error frame, a frame indicating that the own device cannot communicate in the mesh network can be used, and for example, a path error frame in the IEEE802.11s standard can be used.

The STP control unit 15 is a control unit that performs STP protocol processing (also simply referred to as “STP processing”). The STP control unit 15 transmits the STP BPDU (Bridge Protocol Data Unit) by the wired IF11 and the wireless IF12. Further, the BPDU transmitted by another base station M is received by the wired IF11 and the wireless IF12. Then, based on the STP process, the wired IF 11 is controlled as to which of the plurality of states including the forwarding state and the blocking state. Here, the forwarding state means a state in which frames can be transmitted and received, and the blocking state means a state in which frames cannot be transmitted and received except for receiving BPDUs.

The route control unit 16 is a processing unit that controls the construction or deletion of communication paths in the mesh network. The route control unit 16 communicates with another base station M by the routing protocol of the mesh network, and the route table 17 showing the next hop device of the communication route used for communication with each of the base stations M constituting the mesh network. Is generated and managed. In addition, a terminal table 18 indicating which base station M the terminal connected to the mesh network is connected to is generated and stored.

Further, the route control unit 16 determines whether or not the frame transferred by the transfer unit 14 has reached the destination terminal. Then, the route control unit 16 deletes the terminal table 18 when it is determined that the frame does not reach the destination terminal. In the above determination, for example, when a reception response frame (ACK frame) for a frame transferred by the transfer unit 14 is received by the transmitting interface, it is determined that the frame transferred by the transfer unit 14 has reached the destination terminal. If not, it is determined that the destination terminal is not reached. Further, for example, when an error frame is received, it is determined that the destination terminal is not reached. Note that deleting the terminal table 18 means deleting the entry related to the destination terminal in the terminal table 18.

After deleting the terminal table 18 as described above, the route control unit 16 creates a new terminal table 18 in order to transfer the frame to the destination terminal. Specifically, when the terminal table 18 is deleted, the route control unit 16 generates a new terminal table 18 by transmitting and receiving a search frame for searching the destination terminal by the wireless IF 12. The search frame is transmitted and received, for example, by transmitting an ARP (Address Resolution Protocol) request frame for resolving the MAC address of the destination terminal and receiving an ARP reply frame for the ARP request frame. This search process is a process normally performed by a process related to the routing protocol of the mesh network when there is no entry in the terminal table 18. That is, this search process is performed by the process related to the routing protocol when the terminal table 18 is deleted.

For example, the reason why the frame cannot reach the destination terminal as described above occurs when the wired IF11 in the forwarding state of the wired IF11s included in each of the other two or more base stations M transitions to the blocking state. At this time, the route control unit 16 sets a new terminal table 18 by transmitting and receiving a search frame via the wired IF 11 newly transitioned to the forwarding state among the wired IF 11 provided by each of the two or more base stations M. Generate. As a result, the base station M1 generates new terminal information using the search frame received via the wired interface in the communication permitted state, so that the generated terminal information uses the wired interface in the communication permitted state. It will be consistent with the communication path that has passed through.

FIG. 3 is an explanatory diagram of the route table 17 according to the present embodiment. Specifically, the route table 17 shown in FIG. 3 is a route table included in the base station M1.

As shown in FIG. 3, each entry in the route table 17 includes a next hop address 31 and a destination address 32. Each entry in the route table 17 has a one-to-one correspondence with one destination address.

The next hop address 31 is the address of the base station M (also referred to as the next hop device) adjacent to its own base station M on the communication path from the base station M to the base station M having the destination address related to the entry. ..

The destination address 32 is a destination address related to the entry. When the destination address 32 points to a base station M adjacent to the base station M, both the destination address 32 and the next hop address 31 are the addresses of the base station M.

In the top-level entry in the route table 17 shown in FIG. 3, both the next hop address 31 and the destination address 32 are the MAC addresses of the base station M2. Further, in the entry in the second row from the top in the route table 17, both the next hop address 31 and the destination address 32 are the MAC addresses of the base station M3. The description of "M2" in FIG. 3 indicates the MAC (Medium Access Control) address of the base station M2. The same shall apply hereinafter.

FIG. 4 is an explanatory diagram of the terminal table 18 according to the present embodiment.

As shown in FIG. 4, each entry in the terminal table 18 includes a base station address 41 and a terminal address 42. Each entry in the terminal table 18 is associated with one terminal address on a one-to-one basis.

The base station address 41 is the address of the base station M to which the terminal related to the entry is connected among the base stations M and the like.

The terminal address 42 is the address of the terminal related to the entry.

In the terminal table 18 shown in FIG. 4, it is shown that the terminal T2 is connected to the base station M2.

When the transfer unit 14 receives a frame from any of the interfaces of the wired IF 11 and the wireless IF 12 and 13, the transfer unit 14 refers to the destination address of the received frame. When the terminal related to the destination address can communicate directly from the base station M, that is, without going through another communication device, the frame is transmitted by the interface connected to the destination among the above interfaces. To do.

If the terminal related to the destination of the received frame cannot communicate directly from the base station M, the terminal table 18 is first referred to to identify the base station M to which the terminal is connected, and then the terminal station M is specified. The next hop device for reaching the base station M is specified, and the frame is transmitted by the interface connected to the next hop device.

In this way, the transfer unit 14 transfers the frame by transmitting the frame to the destination address of the received frame by an appropriate interface.

The processing of the base station M configured as described above will be described.

FIG. 5 is a flow chart showing processing of the base station M according to the present embodiment. The series of processes shown in FIG. 5 show a process in which the terminal T1 transmits a frame to the terminal T2 after the construction of the communication path by the base station M is completed.

As shown in FIG. 5, in step S100, the STP control unit 15 and the route control unit 16 perform STP processing and processing based on the routing protocol to generate and manage the route table 17 and the terminal table 18. ..

In step S101, the transfer unit 14 determines whether or not a frame has been received from any of the interfaces of the wired IF11 and the wireless IFs 12 and 13. If a frame is received from any of the above interfaces (Yes in step S101), the process proceeds to step S102, and if not (No in step S101), step S101 is executed again. That is, the transfer unit 14 takes a standby state in step S101 until a frame is received from any of the above interfaces.

In step S102, as described above, the transfer unit 14 refers to the route table 17 and the terminal table 18 managed by the route control unit 16 and transmits the frame received in step S101 by any of the above interfaces. Transfer by doing.

In step S103, the route control unit 16 determines whether or not the frame transferred in step S102 has reached the destination terminal. If it is determined that the destination terminal has been reached, the series of processes shown in FIG. 5 is terminated, and if not, the process proceeds to step S104.

In step S104, the route control unit 16 deletes the entry in the terminal table 18.

In step S105, the route control unit 16 performs a process of searching for the terminal T2. This processing is performed, for example, by transmitting an ARP request frame for resolving the MAC address of the terminal T2, and receiving an ARP reply frame transmitted by the terminal T2 in response to the ARP request frame.

In step S106, the route control unit 16 generates the terminal table 18 based on the result of the search process of the terminal T2 performed in step S105.

Through the above series of processes, when communication from the base station M to the terminal is not possible in the mesh network, the communication path can be appropriately switched to enable communication.

Next, the process when the terminal T1 transmits a frame to the terminal T2 via the communication system 1 will be described more specifically.

FIG. 6 is a sequence diagram showing normal processing in the communication system 1 according to the embodiment. FIG. 6 shows the processing of STP by the base stations M1, M2 and M3, and the processing when the data frame is transmitted from the terminal T1 to the terminal T2 in the state where the construction of the communication path in the mesh network is completed. There is. At this time, the wired IF11 of the base station M2 is in the forwarding state, and the wired IF11 of the base station M3 is in the blocking state. Further, the terminal table 18 included in the base station M1 indicates that the terminal T2 is connected to the base station M2.

In step S201, terminal T1 transmits a data frame. The radio IF12 of the base station M1 receives the data frame transmitted by the terminal T1.

In step S211 the transfer unit 14 of the base station M1 transfers the frame received in step S201 to the base station M2 with reference to the terminal table 18. This process corresponds to step S102 (see FIG. 5). The base station M2 receives the transmitted frame.

In step S221, the transfer unit 14 of the base station M2 transfers the frame received in step S211 to the terminal T2 with reference to the terminal table 18. This process corresponds to step S102 (see FIG. 5). The terminal T2 receives the transmitted frame.

In this way, the data frame transmitted by the terminal T1 reaches the terminal T2.

FIG. 7 is a sequence diagram showing processing when a failure occurs in the communication system 1 according to the present embodiment. FIG. 7 shows the processing of each device when the base station M2 fails in the state of FIG. 6 and the base station M2 becomes unable to communicate.

In FIG. 7, when a failure occurs in the base station M2, the base station M3 does not receive the BPDU from the base station M2 after the failure occurs.

In step S331, the base station M3 performs STP processing based on the fact that the BPDU from the base station M2 is no longer received, and the wired IF 11 transitions to the forwarding state.

In step S301, when the terminal T1 transmits a data frame, the radio IF 12 of the base station M1 receives the data frame.

In step S311 the transfer unit 14 of the base station M1 transfers the frame received in step S301 to the base station M2 with reference to the terminal table 18. This process corresponds to step S102 (see FIG. 5). Since the base station M2 has a failure, it cannot receive the data frame transmitted by the base station M1.

In step S312, the route control unit 16 of the base station M1 does not receive the ACK frame for the data frame transmitted by the transfer unit 14 in step S311 from the base station M2, so that the transmitted data frame reaches the terminal T2. It is determined that there was no such thing, and the terminal table 18 is deleted. This process corresponds to steps S103 and S104 (see FIG. 5).

In step S313, the route control unit 16 performs a process of searching for the terminal T2. Specifically, the route control unit 16 broadcasts an ARP request packet in which the IP address of the terminal T2 is set as the target IP address in the mesh network, and receives the ARP reply packet which is the response. This process corresponds to step S105 (see FIG. 5).

In step S314, the route control unit 16 generates a new terminal table 18 based on the result of the search process in step S313. The new terminal table 18 shows that the terminal T2 is connected to the base station M3. The terminal table 18 is consistent with the communication path via the base station M3 that has newly transitioned to the forwarding state.

In step S302, terminal T1 transmits a data frame. The radio IF12 of the base station M1 receives the data frame transmitted by the terminal T1.

In step S315, the transfer unit 14 of the base station M1 transfers the frame received in step S302 to the base station M3 with reference to the terminal table 18. This process corresponds to step S102 (see FIG. 5). The base station M3 receives the transmitted frame.

In step S332, the transfer unit 14 of the base station M3 transfers the frame received in step S315 to the terminal T2 with reference to the terminal table 18. This process corresponds to step S102 (see FIG. 5). The terminal T2 receives the transmitted frame.

In this way, among the base stations M2 and M3 connected to the destination terminal via the wired IF11, the route control unit 16 is in a state in which the base station M2 in which the wired IF11 is in the forwarding state cannot communicate (failure occurs). When the frame cannot reach the destination terminal based on the above, the terminal table 18 is deleted. As a result, the route control unit 16 generates a new terminal table 18. The newly generated communication path is a communication path that goes through the base station M3. The same applies when the base station M2 transitions to the blocking state due to STP processing for some reason.

FIG. 8 is a sequence diagram showing a process at the time of failure recovery in the communication system 1 according to the present embodiment. FIG. 8 shows the processing of each device when the failure of the base station M2 is recovered and the base station M2 is in a communicable state in the state where communication is possible after the failure of FIG. 7.

In FIG. 8, when the failure of the base station M2 is recovered, the wired IF 11 of the base station M2 starts transmitting and receiving the BPDU after a lapse of a predetermined time.

In step S421, the wired IF11 of the base station M2 transitions to the forwarding state by the STP process based on the result of transmission / reception of the BPDU with the base station M3.

In step S431, the wired IF11 of the base station M3 transitions to the blocking state by the STP process based on the result of transmission / reception of the BPDU with the base station M2.

In step S401, when the terminal T1 transmits a data frame, the radio IF 12 of the base station M1 receives the data frame.

In step S411, the transfer unit 14 of the base station M1 transfers the frame received in step S401 to the base station M3 with reference to the terminal table 18. This process corresponds to step S102 (see FIG. 5). The base station M3 receives the transmitted frame, but since the wired IF11 is in the blocking state, it is prohibited to transmit the received frame by the wired IF11.

In step S432, the base station M3 transmits an error frame to the base station M3 by the transfer unit 14 based on the prohibition of transmitting the frame in step S411. The route control unit 16 of the base station M1 receives an error frame from the base station M3.

In step S412, the route control unit 16 of the base station M1 deletes the terminal table 18 based on the fact that the error frame is received in step S432. This process corresponds to steps S103 and S104 (see FIG. 5).

In steps S413 and S414, the route control unit 16 performs a process of searching for the terminal T2, and generates a new terminal table 18 based on the result of the search process. This process is the same as in steps S313 and S314 (see FIG. 6). The new terminal table 18 shows that the terminal T2 is connected to the base station M2. The terminal table 18 is consistent with the communication path via the base station M2 that has newly transitioned to the forwarding state.

In step S402, terminal T1 transmits a data frame. The radio IF12 of the base station M1 receives the data frame transmitted by the terminal T1.

In step S415, the transfer unit 14 of the base station M1 transfers the frame received in step S402 to the base station M2 with reference to the terminal table 18. This process corresponds to step S102 (see FIG. 5). The base station M2 receives the transmitted frame.

In step S422, the transfer unit 14 of the base station M2 transfers the frame received in step S415 to the terminal T2 with reference to the terminal table 18. This process corresponds to step S102 (see FIG. 5). The terminal T2 receives the transmitted frame.

In this way, the route control unit 16 is in a communicable state (failure occurred) among the base stations M2 and M3 connected to the destination terminal via the wired IF11. When the frame cannot reach the destination terminal based on the failure recovery), the terminal table 18 is deleted. As a result, the route control unit 16 generates a new terminal table 18. The newly generated communication path is a communication path that goes through the base station M2.

It is also possible to configure another type of communication system by using the base station M in the present embodiment. Another form of communication system will be described below.

FIG. 9 is a schematic diagram showing a configuration of a communication system 1A, which is another form of the communication system according to the present embodiment, and a communication path in a normal state.

As shown in FIG. 9, the communication system 1A includes eight base stations M11 to M18 and a hub 20.

Each of the base stations M11 to M18 is the same communication device as the base station M of the communication system 1. Further, the hub 20 is the same as the hub 20 of the communication system 1.

In the communication system 1A, three base stations M16, M17 and M18 are connected to the terminal T2 via a hub 20 by a wired IF11. Then, by the STP process, the wired IF11 of the base station M17 is set to the forwarding state, and the wired IF11 of the base stations M16 and M18 is set to the blocking state.

The communication path from the base station M11 to the terminal T2 is a communication path that passes through the base stations M11, M13, and M17 in this order, as shown by arrows in FIG.

At this time, the route table 17 of the base station M11 shows that the next hop device in the communication path to the base station M17 is the base station M13. Further, the terminal table 18 included in the base station M11 shows that the terminal T2 is connected to the base station M17.

When the terminal T1 transmits a data frame destined for the terminal T2, the data frame reaches the terminal T2 via the base stations M11, M13 and M17.

In this state, a communication path when a failure occurs in the base station M17 will be described with reference to FIG.

FIG. 10 is a schematic diagram showing a communication path when a failure occurs in the communication system 1A, which is another form of the communication system according to the present embodiment.

First, the STP process causes the wired IF11 of the base station M18 to transition to the forwarding state, and the wired IF11 of the base station M16 maintains the blocking state.

The communication path from the base station M11 to the terminal T2 is changed to a communication path that goes through the base stations M11, M14, and M18 in this order, as shown by the arrows in FIG. 10, following the process described in FIG. Will be done.

At this time, the route table 17 included in the base station M11 shows that the next hop device in the communication path to the base station M18 is the base station M14. Further, the terminal table 18 included in the base station M11 shows that the terminal T2 is connected to the base station M18.

When the terminal T1 transmits a data frame destined for the terminal T2, the data frame reaches the terminal T2 via the base stations M11, M14 and M18.

As described above, the communication device according to the present embodiment generates terminal information necessary for transmitting a frame to the destination terminal by deleting the terminal information when the transferred frame cannot reach the destination terminal. It is possible to create an opportunity to perform the subsequent processing. When the terminal information is deleted in this way, the communication device subsequently generates new terminal information and transfers the frame to the destination terminal using the generated new terminal information. The communication path for communication from within the mesh network to the destination terminal is a communication path that passes through a communication device that is in a communication permitted state among communication devices equipped with a wired interface, and the terminal information is terminal information consistent with the above communication path. It has become. At this time, if some factor occurs and the communication device in the communication permitted state transitions to the communication prohibited state by the processing of the loop avoidance protocol, communication to the destination terminal via the communication path becomes impossible. Therefore, if terminal information is newly generated when such a state transition occurs, the newly generated terminal information is a terminal that matches the communication path via the communication device that has newly transitioned to the communication permission state. It becomes information. As a result, the frame transmitted by the source terminal can reach the destination terminal according to the new communication path and terminal information. As described above, the communication device according to the present embodiment can appropriately switch the communication path in the mesh network.

Further, the communication device can transfer the frame toward the destination terminal by using the new terminal information generated by deleting the terminal information. Therefore, the communication device can appropriately switch the communication path in the mesh network.

In addition, when the communication device connected to the wired network becomes incommunicable, the communication device avoids the communication device in the incommunicable state and newly generates a communication path to the destination terminal. .. In this way, the communication device can be appropriately switched to a new communication path that avoids the communication device that has become incommunicable.

Further, the communication device newly generates a communication path to the destination terminal via the communication device in the communicable state when the communication device in the communicable state becomes communicable. In this way, the communication device can be appropriately switched to a new communication path via the communication device that has become communicable.

The communication device also uses the route information to transfer frames within the mesh network. As a result, even when the communication device is not adjacent to the communication device shown in the terminal information, the frame can be transmitted to the destination obtained by using the route information.

The present invention can be realized not only as an apparatus, but also as a method in which the processing means constituting the apparatus is used as a step, as a program for causing a computer to execute those steps, or as a computer reading in which the program is recorded. It can also be realized as a possible recording medium such as a CD-ROM, or as information, data or a signal indicating the program. Then, those programs, information, data and signals may be distributed via a communication network such as the Internet.

Although the communication device and the like of the present invention have been described above based on the embodiment, the present invention is not limited to this embodiment. As long as the gist of the present invention is not deviated, various modifications that can be thought of by those skilled in the art are applied to the present embodiment, and a form constructed by combining components in different embodiments is also included in the scope of the present invention. ..

The present invention can be applied to a communication device that appropriately switches a communication path in a mesh network. Specifically, it can be applied to so-called mesh points, which are base stations constituting a mesh network.

1, 1A communication system 11 Wired IF
12, 13 wireless IF
14 Transfer unit 15 STP control unit 16 Route control unit 17 Route table 18 Terminal table 20 Hub 31 Next hop address 32 Destination address 41 Base station address 42 Terminal address M, M1, M2, M3, M11, M12, M13, M14, M15 , M16, M17, M18 Base station T1, T2 terminal

Claims (7)

A communication device that is one of a plurality of communication devices that make up a mesh network.
The mesh network is communicably connected to the destination terminal via a wired interface provided in each of two or more communication devices among the plurality of communication devices.
The wired interface provided in each of the two or more communication devices is dynamically set to either a communication permitted state or a communication prohibited state by a protocol for avoiding a loop.
The one communication device is
A wireless interface that wirelessly communicates with the source terminal,
Among the plurality of communication devices, a route control unit that manages terminal information indicating a communication device connected to the destination terminal via the wired interface, and a route control unit.
When the source terminal receives a frame transmitted to the destination terminal by the wireless interface, the received frame is transferred to the communication device indicated in the terminal information into the mesh network. With a department
The route control unit
It is determined whether or not the frame transferred by the transfer unit has reached the destination terminal.
If the frame in which the transfer unit is transferred is determined that could not be reached to the destination terminal, to delete the terminal information,
A communication device that generates new terminal information by transmitting and receiving a search frame for searching the destination terminal by the wireless interface when the terminal information is deleted. When the wired interface of the communication device becomes incommunicable, the wired interface of the second communication device different from the communication device among the two or more communication devices is put into the communication permitted state by the protocol. After becoming
When the frame cannot reach the destination terminal based on the communication device in which the wired interface is in the communication permitted state becomes incommunicable state among the two or more communication devices. the communication apparatus according to claim 1 to delete the terminal information. The path control unit, by the protocol based on said wired interface is the communication apparatus becomes incommunicable state has become communicable state, the wired interface is a communication disabled state in which the second communication device has by became, if the frame can not reach the destination terminal, the communication apparatus according to claim 2 to remove said terminal information. The route control unit further
In the mesh network, the route information storing the next hop device in the communication path from the one communication device to the communication device shown in the terminal information is managed.
The transfer unit
The communication device according to any one of claims 1 to 3 , wherein the received frame is transmitted to the next hop device on the communication path to transfer the frame. The communication device is
The protocol is STP (Spanning Tree Protocol).
The communication permission state is the forwarding state specified by STP.
The communication device according to any one of claims 1 to 4 , wherein the communication prohibited state is a blocking state defined by STP. It is a communication device of one of a plurality of communication devices constituting a mesh network, and is a control method of a communication device having a wireless interface for wireless communication with a source terminal.
The mesh network is communicably connected to the destination terminal via a wired interface provided in each of two or more communication devices among the plurality of communication devices.
The wired interface provided in each of the two or more communication devices is dynamically set to either a communication permitted state or a communication prohibited state by a protocol for avoiding a loop.
The control method is
A route control step that manages terminal information indicating a communication device connected to the destination terminal via the wired interface among the plurality of communication devices.
When the source terminal receives a frame transmitted to the destination terminal by the wireless interface, the received frame is transferred to the communication device indicated in the terminal information into the mesh network. Including steps
In the route control step,
It is determined whether or not the frame transferred in the transfer step has reached the destination terminal.
If the frame has been transferred in the transfer step it has determined that could not be reached to the destination terminal, to delete the terminal information,
A control method for generating new terminal information by transmitting and receiving a search frame for searching the destination terminal by the wireless interface when the terminal information is deleted. A program for causing a computer to execute the control method according to claim 6.

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