JP6777942B2 - Communication device, communication system, and control method of communication device - Google Patents

Description

The present invention relates to a communication device, a communication system, and a method for controlling the communication device.

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 is performed.

A plurality of communication devices constituting the mesh network have route information indicating a route to each communication device and attribution information indicating which communication device is connected (attributable) to which communication device. ing. Each communication device transfers a frame transmitted by a terminal connected to the mesh network using route information and attribution information, so that the terminal of the communication partner connected to the mesh network (simply also referred to as the terminal of the communication partner). To reach. In this way, frames can be exchanged between terminals connected to the mesh network.

Patent Document 1 discloses a technique relating to a bridge function in a gateway device that connects a mesh network and another network connected to the mesh network. The gateway device disclosed in Patent Document 1 relays a packet between the mesh network and the other network without performing address translation of the packet to be transferred.

Japanese Unexamined Patent Publication No. 2008-193183

Each communication device constituting the mesh network generally generates attribution information based on the information contained in the frame transmitted by the terminal connected to the mesh network.

Specifically, each communication device can generate attribution information by intercepting a frame for ARP resolution performed by terminals connected to a mesh network prior to data communication. In this case, when the terminals try to perform data communication that does not require ARP resolution, the attribution information is not generated in each communication device, and the terminals connected to the mesh network cannot send and receive frames. There is a problem.

The present invention has been made to solve the above problems, and is a communication device or the like capable of communicating between terminals via a mesh network even when the terminal of the communication partner does not transmit a frame. The purpose is to provide.

In order to solve the above problems, the communication device 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 has a first interface for wireless communication with a first terminal. , A second interface that wirelessly communicates with another communication device other than the one communication device among the plurality of communication devices, a terminal connected to the mesh network, and the terminal among the plurality of communication devices. The attribution information includes a storage unit that stores attribution information associated with the communication device to which it belongs, and a second terminal that is a search unit and is the destination of a data frame received from the first terminal. If not, (a) a search frame including the destination IP (Internet Protocol) address of the data frame is broadcasted by the second interface, and (b) the second terminal receives the search frame. By receiving the received response frame and (c) referring to the received response frame, the second terminal, which is the source of the response frame, and the communication device to which the second terminal belongs can be connected. A transfer that transmits the data frame received from the first terminal by the second interface based on the search unit and the attribution information after the search unit has registered the attribution information in association with each other. It has a part.

According to this, when the destination of the data frame received from the first terminal does not exist in the attribution information, the communication device can transfer the data frame after generating the attribution information by exchanging the search frame and the response frame. Therefore, even if the communication device does not have the attribution information of the first terminal at the time of receiving the data frame due to factors such as the need for ARP resolution by the terminal when transmitting and receiving the data frame, the data Frames can be transferred properly. As described above, according to the communication device, even when the data frame is received without the attribution information of the terminal of the communication partner, the terminals can communicate with each other via the mesh network.

Further, the search unit may broadcast the search frame by broadcasting the search frame.

According to this, the communication device enables communication between terminals via a mesh network by performing broadcast transmission using broadcast transmission. Broadcast transmission includes multicast transmission and broadcast transmission, but multicast transmission is generally rarely used, and in order to send and receive multicast frames, special settings that are different from normal settings for other communication devices and terminals. May be required. On the other hand, broadcast transmission is commonly used in ordinary communication. Therefore, by using broadcast transmission, the communication device enables communication between terminals via a mesh network without making special settings different from usual.

Further, in the above (a), the search unit broadcasts an ARP (Address Resolution Protocol) request frame including the destination IP address of the data frame as a target IP address as the search frame, and transmits the ARP (Addless Resolution Protocol) request frame as the search frame. In (c), the ARP reply frame transmitted in response to the reception of the ARP request frame by the second terminal is received as the response frame, and the physical header of the received ARP reply frame is referred to in the above (c). Then, the second terminal and the communication device to which the second terminal belongs may be associated and registered in the attribution information.

According to this, the communication device uses the ARP request frame and the ARP reply frame as the search frame and the response frame, respectively, to enable communication between terminals via the mesh network. By doing so, the second terminal can transmit the response frame to the search frame by using the standard function of IP communication. In other words, the terminal does not need to have a special function of transmitting a response frame to the search frame transmitted by the communication device. Therefore, the communication device enables communication between terminals via a mesh network without providing the terminals with special functions.

Further, the storage unit further stores the route information in the mesh network, and the communication device is a communication device to which the second terminal belongs, which the search unit has registered in the attribution information. The transfer unit includes a route construction unit that acquires route information indicating a communication route leading to the above and registers it in the route information by using a dynamic routing protocol, and the transfer unit is the route information after the route construction unit registers the route information. The data frame may be transmitted based on the above.

According to this, the communication device generates the route information to the communication device to which the second terminal belongs in the mesh network, triggered by the generation of the attribution information of the second terminal. As a result, the communication device enables more reliable communication between the terminals via the mesh network by establishing a communication path to the communication device to which the second terminal belongs.

Further, in order to solve the above problems, the communication system according to one aspect of the present invention includes the above communication devices as each of a plurality of communication devices constituting the mesh network.

According to this, the same effect as that of the wireless communication device is obtained.

Further, in order to solve the above problems, the control method of the communication device according to one aspect of the present invention is a control method of one of a plurality of communication devices constituting the mesh network, and the communication device is described. Is connected to the mesh network with a first interface that wirelessly communicates with a first terminal, a second interface that wirelessly communicates with another communication device other than the one communication device among the plurality of communication devices. The control method includes a terminal and a storage unit that stores attribution information associated with the communication device to which the terminal belongs among the plurality of communication devices, and the control method is a search step. When the second terminal, which is the destination of the data frame received from one terminal, does not exist in the attribution information, (a) a search frame including the destination IP (Internet Protocol) address of the data frame is broadcast by the second interface. By transmitting, (b) receiving the response frame transmitted in response to the second terminal receiving the search frame, and (c) referring to the received response frame, the source of the response frame Based on a search step in which a second terminal is associated with a communication device to which the second terminal belongs and registered in the attribution information, and the attribution information after the registration in the search step. A transfer step of transmitting the data frame received from the first terminal by the second interface is included.

According to this, the same effect as that of the wireless communication device is obtained.

It should be noted that 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 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 enables communication between terminals via a mesh network even when the terminal of the communication partner does not transmit a frame.

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 functional block of the communication device according to the embodiment. FIG. 3 is an explanatory diagram showing an example of attribution information according to the embodiment. FIG. 4 is an explanatory diagram showing an example of route information according to the embodiment. FIG. 5 is an explanatory diagram showing a frame format of the search frame according to the embodiment. FIG. 6 is an explanatory diagram showing a frame format of the response frame according to the embodiment. FIG. 7 is a flow chart showing processing of the communication device according to the embodiment. FIG. 8 is a sequence diagram showing processing 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 communication device capable of communicating between terminals via a mesh network will be described even when the terminals of the communication partner are not transmitting frames.

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 communication devices 10A, 10B and 10C. Communication system 1 is a mesh network composed of communication devices 10A, 10B and 10C. Further, terminals T1 and T2 are connected to the communication system 1.

The communication system 1 is deployed in an office or a factory, and terminals T1 and T2 (for example, a personal computer, a smartphone, an industrial device, a sensor, etc., which are simply terminals) which are information communication terminals in the office or the factory are connected. To. It is assumed that the terminals T1 and T2 move by being carried by a person or self-propelled.

Here, a case where the communication system 1 is composed of three communication devices 10A and the like will be described as an example, but the communication device 10A and the like may be two or four or more. .. Further, although the arrangement of the communication devices in the communication system 1 is one-dimensional in the figure, it may be two-dimensional or three-dimensional.

The communication device 10A is connected to the communication device 10B, which is another communication device constituting the communication system 1, by wireless communication. Further, the communication device 10A is connected to the terminal T1 by wireless communication.

The communication device 10B is connected to the communication devices 10A and 10C, which are other communication devices constituting the communication system 1, by wireless communication.

The communication device 10C is connected to the communication device 10B, which is another communication device constituting the communication system 1, by wireless communication. Further, the communication device 10C is connected to the terminal T2 by wireless communication.

Each of the communication devices 10A, 10B, and 10C has route information to be used for frame transfer in the communication system 1. For example, the communication devices 10A, 10B, and 10C share route information by providing and acquiring route information from each other using a dynamic routing protocol. The dynamic routing protocol may be a reactive protocol (for example, AODV (Ad hoc On-Demand Distance Vector)) or a proactive protocol (for example, OLSR (Optimized Link State Routing)). Further, the route information may be static information.

Further, each of the communication devices 10A, 10B, and 10C holds attribution information indicating a terminal belonging to the own device and shares it with each other. Since the terminal can move, the communication device to which the terminal belongs can fluctuate without being fixed. Therefore, the attribution information can be dynamically changed by moving the terminal. The communication device 10A or the like updates the attribution information by repeatedly providing the attribution information of its own device to another communication device and repeatedly acquiring the attribution information from the other communication device. Here, attribution means that the terminal connects to the communication device. The same shall apply hereinafter.

Hereinafter, a process in which the terminal T1 transmits a frame destined for the terminal T2 and the terminal T2 receives the frame in a state where the communication device 10A or the like does not have the attribution information of the terminals T1 and T2 will be described. To do.

Here, it is assumed that the terminal T1 initially possesses the IP (Internet Protocol) address of the terminal T2, and does not possess the MAC (Media Access Control) address of the terminal T2. Further, it is assumed that a WDS (Wireless Distribution System) frame format is used for communication between the communication devices 10A and the like, and a mesh control field compliant with IEEE802.11s is used. The MAC address corresponds to the physical address.

First, the terminal T1 generates an ARP request frame for acquiring the MAC address of the terminal T2, and broadcasts the ARP request frame. The transmitted ARP request frame is transferred in this order by the communication devices 10A, 10B, and 10C, and reaches the terminal T2.

When the terminal T2 receives the ARP request frame, it generates an ARP reply frame including the MAC address of its own device and transmits the ARP reply frame to the terminal T1 as a destination. The transmitted ARP reply frame is transferred in this order by the communication devices 10C, 10B, and 10A, and reaches the terminal T1.

At the time of the transfer processing of the ARP reply frame, the communication device 10A or the like can generate attribution information. Specifically, the communication device 10A acquires the MAC address of the communication device 10C from the Addless 4 (mesh source address, Mesh Source Address) field included in the MAC header of the ARP reply frame received from the communication device 10B. Then, the MAC address of the terminal T2 is acquired from the Address 6 (source address, Source Address) included in the mesh control field of the MAC header. The fields included in the MAC header and the mesh control fields will be described in detail later (see FIGS. 5 and 6).

As a result, attribution information indicating that the terminal T2 belongs to the communication device 10C can be generated. The same description holds for the communication device 10B.

After the attribution information is generated in this way, when the terminal T1 transmits a frame destined for the terminal T2, the frames are transferred in this order by the communication devices 10A, 10B and 10C, and reach the terminal T2.

However, this method is executed by triggering the terminal T1 to initially transmit an ARP request frame for acquiring the MAC address of the terminal T2. Therefore, when the terminal T1 does not transmit the ARP request frame, the attribution information is not generated by this method, and there may be a problem that the terminals connected to the communication system 1 cannot transmit and receive the frame. The terminal T1 does not transmit the ARP request frame, for example, when the terminal T1 initially holds the MAC address of the terminal T2 by static setting or dynamic acquisition.

Therefore, even when the terminal T1 initially possesses the MAC address of the terminal T2, the communication device 10A and the like that acquire the attribution information and enable communication between the terminals will be described below.

FIG. 2 is a block diagram showing a functional block of the communication device 10A according to the present embodiment. FIG. 3 is an explanatory diagram showing an example of attribution information 21 according to the present embodiment. FIG. 4 is an explanatory diagram showing an example of the route information 22 according to the present embodiment.

As shown in FIG. 2, the communication device 10A includes communication IFs 11 and 12, a transfer unit 13, a search unit 14, a storage unit 15, and a route construction unit 16.

The communication IF 11 is a communication interface that wirelessly communicates with the terminal T1 which is a terminal connected to the mesh network. The communication IF11 is, for example, a communication interface of a wireless LAN (Local Area Network) compliant with IEEE802.11a, b, g, and n. It is assumed that the communication IF 11 operates as an access point in the infrastructure mode and connects to the terminal T1 operating as a station. In the infrastructure mode, the terminal T1 is connected (that is, attributed) to the access point as a station, which is a normal usage in an office or the like. Therefore, when the communication IF 11 operates as an access point in the infrastructure mode, there is an advantage that the terminal T1 can be connected to the communication device 10A by a normal usage method. The communication IF 11 may operate in the ad hoc mode. In this case, the terminal T1 also needs to operate in the ad hoc mode.

The communication IF 12 is a communication interface that wirelessly communicates with other communication devices other than the own device among the communication devices constituting the mesh network. The communication IF12 is, for example, a wireless LAN communication interface conforming to IEEE802.11a, b, g, n. The communication IF 12 may operate in the infrastructure mode or in the ad hoc mode.

The communication IFs 11 and 12 may be realized by one wireless communication module (not shown) including a wireless communication chip. On the other hand, each of the wireless IFs 11 and 12 may be realized by one wireless communication module including a wireless communication chip, that is, the communication IFs 11 and 12 may be realized by a total of two wireless communication modules.

The transfer unit 13 is a processing unit that transmits the data frame received by the communication IF 11 by the communication IF 12 based on the destination information and the attribution information 21 of the data frame. Specifically, the transfer unit 13 acquires the destination MAC address (that is, the MAC address of the terminal T2) from the destination address field of the MAC header of the data frame received from the terminal T1 by the communication IF11, and the terminal having the destination MAC address. The communication device 10C, which is the communication device to which T2 belongs, is acquired from the attribution information 21. The method of acquiring attribution information will be described later. Then, the transfer unit 13 sets the MAC address of the communication device 10C to which the terminal T2 having the destination MAC address belongs in the Addless3 (mesh destination address, Mesh Destination Addless) field of the MAC header, and sets the above data frame. Is transferred to the communication device 10B.

The search unit 14 is a processing unit that performs a search process for generating attribution information of the terminal T2, which is the destination of the data frame received from the terminal T1.

Specifically, when the destination MAC address of the data frame received from the terminal T1 does not exist in the terminal information, the search unit 14 uses the search frame including the destination IP address of the data frame (that is, the IP address of the terminal T2). Broadcast by communication IF12. In addition, the search unit 14 receives the response frame transmitted in response to the terminal T2 receiving the search frame by the communication IF 12. Then, the search unit 14 associates the physical address of the terminal T2 included in the MAC header of the received response frame with the communication device 10C to which the terminal T2 belongs and registers it in the attribution information 21. When the search unit 14 registers the terminal T2 in the attribution information 21 in this way, the transfer unit 13 transmits the data frame received from the terminal T1 by the communication IF 12 based on the registration information 21.

The search unit 14 may broadcast the search frame by broadcasting the search frame. Broadcast transmission includes multicast transmission and broadcast transmission, but multicast transmission is generally rarely used, and is different from normal for other communication devices 10B and the like and terminal T2 in order to transmit and receive multicast frames. Special settings may be required. On the other hand, broadcast transmission is commonly used in ordinary communication. Therefore, by using the broadcast transmission, the search unit 14 enables communication between terminals via the mesh network without making special settings different from the usual ones.

Further, the search unit 14 may broadcast the ARP request frame including the destination IP address of the data frame as the target IP address as the search frame. In this case, the search unit 14 receives the ARP reply frame transmitted in response to the reception of the ARP request frame by the terminal T2 as the response frame. Then, the search unit 14 registers the terminal T2 and the communication device 10C, which is the communication device to which the terminal T2 belongs, in the attribution information 21 by referring to the physical header of the received ARP reply frame. .. By doing so, the terminal T2 can transmit a response frame to the search frame by using the standard function of IP communication. In other words, there is an advantage that the terminal T2 does not need to have a special function of transmitting a response frame to the search frame transmitted by the communication device.

The storage unit 15 is a storage device that stores the attribution information 21 and the route information 22.

The attribution information 21 is information in which a terminal connected to the mesh network is associated with a communication device to which the terminal belongs among the communication devices 10A and the like. An example of attribution information 21 is shown in FIG. The attribution information 21 shown in FIG. 3 indicates that the terminal T2 belongs to the communication device 10C. More specifically, in the attribution information 21, the association can be expressed by using the MAC address of the terminal T2 and the MAC address of the communication device to which the terminal belongs.

When the search unit 14 receives the response frame, the attribution information 21 is generated and registered based on the information included in the MAC header of the response frame. Further, the attribution information 21 is referred to by the transfer unit 13, and can be used when the transfer unit 13 determines the transfer destination of the frame.

The route information 22 is information in which the communication device constituting the mesh network and the communication device of the next hop (next hop) for transmitting a frame to the communication device are associated with each other. An example of the route information 22 is shown in FIG. The route information 22 shown in FIG. 4 is information stored in the storage unit 15 of the communication device 10A, and indicates that the communication device of the next hop for transmitting a frame to the communication device 10C is the communication device 10B. There is. The route information 22 is registered by the route construction unit 16. Further, the route information 22 is referred to by the transfer unit 13, and can be used by the transfer unit 13 to determine the communication device of the next hop when the frame is transferred.

The route construction unit 16 is a processing unit that shares route information with other communication devices by using a dynamic routing protocol. The route construction unit 16 stores the route information acquired from another communication device in the storage unit 15 as the route information 22. Specifically, the route construction unit 16 acquires the route information indicating the communication route to the communication device 10C to which the terminal T2 belongs, which is registered in the attribution information 21 by the search unit 14, by using the dynamic routing protocol. And register it as route information 22. When the route construction unit 16 registers the route information 22 as described above, the transfer unit 13 can then transmit a data frame based on the route information 22.

The terminals T1 and T2 are information communication terminals connected to a mesh network, and are, for example, personal computers, smartphones, industrial equipment, sensors, and the like. The terminal T1 communicates with the terminal T2 by transmitting and receiving a communication frame.

For example, when the terminal T1 transmits a frame F1 which is a data frame destined for the terminal T2, the transfer unit 13 of the communication device 10A receives the frame F1 and temporarily holds the frame F1. While the transfer unit 13 holds the frame F1, the search unit 14 broadcasts the frame F2, which is a search frame. The frame F2 is sequentially transferred as frames F3 and F4 by the communication devices 10B and 10C, respectively, and the frame F4 reaches the terminal T2. When the terminal T2 transmits the frame F5, which is a response frame to the search frame, the frames F5 are sequentially transferred as frames F6 and F7 by the communication devices 10C and 10B, respectively, and reach the communication device 10A.

By transmitting and receiving the above frames, the communication devices 10A and 10B generate and hold attribution information 21 indicating that the terminal T2 belongs to the communication device 10C. When the terminal T1 transmits a data frame destined for the terminal T2 in this state, the data frames are transferred in this order by the communication devices 10A, 10B and 10C, and can reach the terminal T2.

The terminal T2 is provided with a response function of transmitting a response frame with the source of the search frame as the destination when the terminal T2 receives the search frame with the own device as the destination IP address. An ARP request frame can be used as the search frame, and an ARP reply frame can be used as the response frame. In this way, the response function can be realized by using the standard function of IP communication, and there is an advantage that the terminal T2 does not need to have the response function. Hereinafter, it will be described that the ARP request frame is used as the search frame and the ARP reply frame is used as the response frame.

Next, the search frame and the response frame will be described in detail.

FIG. 5 is an explanatory diagram showing a frame format of frame F2, which is a search frame according to the present embodiment. The frame F2 shown in FIG. 5 shows in detail the fields included in the frame F2 in FIG.

As shown in FIG. 5, frame F2 has a WDS frame format, has mesh control fields, and includes ARP packets in the MAC payload. The MAC address of the communication device 10A will be referred to as MAC (10A), and the IP address of the communication device 10A will be referred to as IP (10A). The same applies to the communication devices 10B and 10C, and the terminals T1 and T2. Further, the MAC (FF) indicates the broadcast address “ff: ff: ff: ff: ff: ff”, and the MAC (00) indicates “00: 00: 00: 00: 00: 00”. The same shall apply hereinafter.

The frame F2 is an ARP request frame for the communication device 10A to inquire about the MAC address of the terminal T2 using the IP address of the terminal T2.

The frame F2 includes four address fields (Address1 to Address4) and a mesh control field including one address field (Address) in the MAC header. The information contained in these address fields is information conforming to IEEE802.11s, and is as follows.

Addless1: RA (Receiver Addless)
Adress2: TA (Taget Adress)
Address3: DA (Destination Address)
Address4: SA (Source Address)

As shown in FIG. 5, Adsless 1 and 3 of the MAC header of frame F2 include a broadcast address. Further, the addresses 2 and 4 and the address of the mesh control field include the MAC address of the communication device 10A.

Further, in the ARP packet included in the frame F2, the OP code indicates the ARP request, and the source MAC address field and the IP address field are the MAC address and the IP address of the communication device 10A, respectively. The target IP address field is the IP address of the terminal T2. The target MAC address field is optional.

The frame F2 needs to include at least the IP address of the terminal T2 and the MAC address of the communication device 10A, and the destination MAC address must be multicast or broadcast (that is, broadcast).

FIG. 6 is an explanatory diagram showing a frame format of frame F7, which is a response frame according to the present embodiment. The frame F7 shown in FIG. 6 shows in detail the fields included in the frame F7 in FIG.

As shown in FIG. 6, the frame F7 has a WDS frame format and includes an ARP packet in the MAC payload.

The frame F7 is an ARP reply frame indicating the response of the terminal T2 to the frame F2 which is an ARP request frame. Frame F7 includes in the MAC header a mesh control field including four address fields (Address1 to Adlesss4) and two address fields (Address5, Adpress6). Address 5 and 6 are included in the mesh extension address (Mesh Extension Address) portion of the mesh control field.

As shown in FIG. 6, the Adslesss 1, 3 and 5 of the frame F7 include the MAC address of the communication device 10A. The address 2 contains the MAC address of the communication device 10B, the address 4 contains the MAC address of the communication device 10C, and the address 6 contains the MAC address of the terminal T2.

Further, in the ARP packet included in the frame F7 which is the response frame, the OP code indicates the ARP reply, and the source MAC address field and the source IP address field are the MAC address and the IP address of the terminal T2, respectively. Further, the target MAC address field and the target IP address field are the MAC address and the IP address of the terminal T2 of the communication device 10A, respectively.

The frame F7, which is a response frame, includes at least the MAC address of the terminal T2 and the MAC address of the communication device 10A, and an address that the communication device 10A can receive (specifically, the address of the communication device 10A or the broadcast). Address) must be included as the destination IP address or destination MAC address.

The processing of the communication device 10A configured as described above and the processing of the communication system 1 will be described.

FIG. 7 is a flow chart showing processing of the communication device according to the present embodiment. FIG. 8 is a sequence diagram showing the processing of the communication system 1 according to the present embodiment. In addition, in FIG. 7 and FIG. 8, common reference numerals are given to common processes.

In step S101, the transfer unit 13 of the communication device 10A receives the frame F1 which is a data frame by the communication IF 11. The frame F1 is transmitted by the terminal T1. The transfer unit 13 temporarily holds the received frame F1 in a memory or the like.

In step S102, the search unit 14 determines whether or not the destination address included in the MAC header of the frame received by the transfer unit 13 in step S101 exists in the attribution information 21. If it exists (Yes in step S102), the process proceeds to step S108, and if not (No in step S102), the process proceeds to step S103.

In step S103, the search unit 14 generates a frame F2 which is an ARP request frame as a search frame, and broadcasts the frame F2 by the communication IF12. As shown in FIG. 8, the transmitted frame F2 is received by the communication device 10B and broadcast-transmitted as the frame F3. Further, the transmitted frame F3 is received by the communication device 10C, broadcasted as a frame F4, and the frame F4 reaches the terminal T2. When the terminal T2 receives the frame F4 which is the ARP request, the terminal T2 transmits the frame F5 which is the ARP reply frame as a response to the ARP request. The transmitted frame F5 is received by the communication device 10C and transmitted as a frame F6. The transmitted frame F6 is received by the communication device 10B and transmitted as a frame F7.

In step S104, the search unit 14 receives the frame F7, which is an ARP reply frame, by the communication IF12.

In step S105, the MAC address of the communication device 10C and the MAC address of the terminal T2 are associated with each other and registered in the attribution information 21 based on the MAC header of the frame F7, which is the ARP reply frame received in step S104.

In step S106, the route construction unit 16 determines whether or not the MAC address of the communication device 10C exists in the route information 22 of the storage unit 15. If it exists (Yes in step S106), the process proceeds to step S108, and if not (No in step S106), the process proceeds to step S107.

In step S107, the route construction unit 16 registers the route information 22 indicating the route to the communication device 10C in the mesh network.

In step S108, the transfer unit 13 refers to the route information 22 registered in step S106, and transmits the frame F1 from the terminal T1 received and temporarily held in step S101 to the communication device 10B as the frame F8. Forward. The transmitted frame F8 is received by the communication device 10B and transmitted as the frame F9, as shown in FIG. Further, the transmitted frame F9 is received by the communication device 10C and transmitted as a frame F10, and the frame F10 reaches the terminal T2.

In this way, the data frame transmitted by the terminal T1 is transferred by the communication device 10A or the like and received by the terminal T2.

As described above, in the communication device of the present embodiment, when the destination of the data frame received from the first terminal does not exist in the attribution information, the attribution information is generated by exchanging the search frame and the response frame, and then the data is generated. You can transfer frames. Therefore, even if the communication device does not have the attribution information of the first terminal at the time of receiving the data frame due to factors such as the need for ARP resolution by the terminal when transmitting and receiving the data frame, the data Frames can be transferred properly. As described above, according to the communication device, even when the data frame is received without the attribution information of the terminal of the communication partner, the terminals can communicate with each other via the mesh network.

In addition, the communication device enables communication between terminals via a mesh network by performing broadcast transmission using broadcast transmission. Broadcast transmission includes multicast transmission and broadcast transmission, but multicast transmission is generally rarely used, and in order to send and receive multicast frames, special settings different from usual are set for other communication devices and terminals. May be required. On the other hand, broadcast transmission is commonly used in ordinary communication. Therefore, by using broadcast transmission, the communication device enables communication between terminals via a mesh network without making special settings different from usual.

Further, the communication device uses the ARP request frame and the ARP reply frame as the search frame and the response frame, respectively, to enable communication between terminals via the mesh network. By doing so, the second terminal can transmit the response frame to the search frame by using the standard function of IP communication. In other words, the terminal does not need to have a special function of transmitting a response frame to the search frame transmitted by the communication device. Therefore, the communication device enables communication between terminals via a mesh network without providing the terminals with special functions.

Further, the communication device generates route information to the communication device to which the second terminal belongs in the mesh network, triggered by the generation of the attribution information of the second terminal. As a result, the communication device enables more reliable communication between the terminals via the mesh network by establishing a communication path to the communication device to which the second terminal belongs.

Although the communication device of the present invention has 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 conceived 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 and a communication system capable of communicating between terminals via a mesh network even when the terminal of the communication partner does not transmit a frame. More specifically, it can be applied to a communication device constituting a mesh network deployed in an office or a factory.

1 Communication system 10A, 10B, 10C Communication device 11, 12 Communication IF
13 Transfer unit 14 Search unit 15 Storage unit 16 Route construction unit 21 Attribution information 22 Route information F1, F2, F3, F4, F5, F6, F7, F8, F9, F10 Frame T1, T2 terminals

Claims (6)

A communication device that is one of a plurality of communication devices that make up a mesh network.
The first interface that wirelessly communicates with the first terminal,
A second interface that wirelessly communicates with another communication device other than the one communication device among the plurality of communication devices,
A storage unit that stores attribution information in which a terminal connected to the mesh network is associated with a communication device to which the terminal belongs among the plurality of communication devices.
When the second terminal, which is the search unit and is the destination of the data frame received from the first terminal, does not exist in the attribution information.
(A) A search frame including the destination IP (Internet Protocol) address of the data frame is broadcasted by the second interface.
(B) Receiving the response frame transmitted in response to the second terminal receiving the search frame,
(C) By referring to the received response frame, the second terminal, which is the source of the response frame, and the communication device to which the second terminal belongs are associated and registered in the attribution information. , Search department,
A communication device including a transfer unit that transmits the data frame received from the first terminal by the second interface based on the attribution information after the search unit has made the registration. The communication device according to claim 1, wherein the search unit broadcasts and transmits the search frame. The search unit
In the above (a), an ARP (Address Resolution Protocol) request frame including the destination IP address of the data frame as a target IP address is broadcasted as the search frame.
In (b), the ARP reply frame transmitted in response to the reception of the ARP request frame by the second terminal is received as the response frame.
In the above (c), by referring to the physical header of the received ARP reply frame, the second terminal and the communication device to which the second terminal belongs are associated and registered in the attribution information. Item 2. The communication device according to item 1 or 2. The storage unit further stores route information in the mesh network.
The communication device further
A route construction unit that acquires route information indicating a communication route to a communication device to which the second terminal belongs, which is registered in the attribution information by the search unit, using a dynamic routing protocol and registers it in the route information. With
The transfer unit
The communication device according to any one of claims 1 to 3, further transmitting the data frame based on the route information after the route construction unit has made the registration. A communication system including the communication device according to any one of claims 1 to 4 as each of a plurality of communication devices constituting the mesh network. It is a control method of one of a plurality of communication devices constituting a mesh network.
The communication device is
The first interface that wirelessly communicates with the first terminal,
A second interface that wirelessly communicates with another communication device other than the one communication device among the plurality of communication devices,
It includes a terminal connected to the mesh network and a storage unit that stores attribution information associated with the communication device to which the terminal belongs among the plurality of communication devices.
The control method is
In the search step, when the second terminal, which is the destination of the data frame received from the first terminal, does not exist in the attribution information.
(A) A search frame including the destination IP (Internet Protocol) address of the data frame is broadcasted by the second interface.
(B) Receiving the response frame transmitted in response to the reception of the search frame by the second terminal,
(C) By referring to the received response frame, the second terminal, which is the source of the response frame, and the communication device to which the second terminal belongs are associated and registered in the attribution information. , Exploration steps and
A control method including a transfer step of transmitting the data frame received from the first terminal by the second interface based on the attribution information after the registration in the search step.

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