Communication control device, communication control method, communication control program, and communication control system

Abstract

To easily make a communication network redundant.SOLUTION: A first wired communication section 511 includes a wired connection function. A second wired communication section 512 includes a wired connection function. A third wired communication section 513 includes a wired connection function and is connected with a node 21. A wireless communication section 514 includes a wireless communication function to be connectable with a plurality of wireless networks. An identification section 5161 identifies whether or not adjacent apparatuses connected to the first wired communication section 511 or the second wired communication section 512 over a wired network are communication control devices including the same function. A communication control section 5162 includes a bridge function for establishing communication with the other communication control device over a wireless network and further transferring a communication frame to an appropriate destination among the first wired communication section 511, the second wired communication section 512, the third wired communication section 513 and the wireless communication section 514.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a communication control device, a communication control method, a communication control program, and a communication control system. [Background technology]

[0002] BACKGROUND ART Conventionally, in order to make a communication network having a plurality of nodes redundant, a method of connecting each node to a plurality of paths by wire has been known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-112977 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the conventional techniques have a problem in that it is sometimes difficult to achieve redundancy in a communication network.

[0005] For example, in conventional technology, each node needs to be provided with the same number of physical communication ports as the number of connected paths. However, it may be difficult to provide multiple communication ports due to reasons such as miniaturization of nodes.

[0006] A conventional communication control system will be described with reference to Fig. 9. Fig. 9 is a diagram showing a conventional communication control system.

[0007] As shown in FIG. 9, a communication control system 1a includes a switch 11, a node 21a, a node 22a, a node 23a, and a node 24a.

[0008] Here, a node is a device that processes information and performs communication. A node may also be referred to as a computer, etc. A wired communication unit is a communication port.

[0009] The node 21a includes a wired communication unit 211a and a wired communication unit 212a. The wired communication unit 211a is connected to the switch 11. The wired communication unit 212a is connected to the node 22a.

[0010] The node 22a includes a wired communication unit 221a and a wired communication unit 222a. The wired communication unit 221a is connected to the node 21a. The wired communication unit 222a is connected to the node 23a.

[0011] The node 23a includes a wired communication unit 231a and a wired communication unit 232a. The wired communication unit 231a is connected to the node 22a. The wired communication unit 232a is connected to the node 24a.

[0012] The node 24a includes a wired communication unit 241a and a wired communication unit 242a. The wired communication unit 241a is connected to the node 23a. The wired communication unit 242a is connected to the switch 11.

[0013] In this way, the communication control system 1a has a redundant network configuration using a ring topology. However, as mentioned above, if a node cannot be provided with multiple communication ports, the network configuration shown in Figure 9 cannot be realized.

[0014] Furthermore, a network may be made redundant using the topology shown in Fig. 10. As shown in Fig. 10, a communication control system 1b includes a switch 11, a switch 12, a node 21b, a node 22b, a node 23_1b, and a node 23_2b. The nodes 23_1b and 23_2b are made redundant themselves and can exchange data with each other.

[0015] Node 21b includes a wired communication unit 211b, a wired communication unit 212b, a wired communication unit 213b, and a wired communication unit 214b. The wired communication unit 211b is connected to the switch 11. The wired communication unit 212b is connected to node 22b. The wired communication unit 213b is connected to the switch 12. The wired communication unit 214b is connected to node 22b.

[0016] The node 22b includes a wired communication unit 221b, a wired communication unit 222b, a wired communication unit 223b, and a wired communication unit 224b. The wired communication unit 221b is connected to the node 21b. The wired communication unit 222b is connected to the node 23_1b. The wired communication unit 223b is connected to the node 21b. The wired communication unit 224b is connected to the node 23_2b.

[0017] The node 23_1b includes a wired communication unit 231b and a wired communication unit 232b. The wired communication unit 231b is connected to the node 22b.

[0018] The node 23_2b includes a wired communication unit 233b and a wired communication unit 234b. The wired communication unit 233b is connected to the node 22b.

[0019] Thus, in order to achieve redundancy in a conventional communication control system, it was necessary to provide two to four communication ports for each device.

[0020] In one aspect, an object is to easily realize redundancy in a communication network. [Means for solving the problem]

[0021] According to one aspect, the communication control device includes a first wired communication unit having a wired connection function, a second wired communication unit having a wired connection function, a third wired communication unit having a wired connection function and connected to a node, a wireless communication unit having a wireless communication function that can connect to multiple wireless networks, an identification unit that identifies whether adjacent devices connected to the first wired communication unit or the second wired communication unit via a wired network are communication control devices having the same function, and a communication control unit that establishes communication via the wireless network with other communication control devices and further has a bridging function that transfers communication frames to appropriate destinations between the first wired communication unit, the second wired communication unit, the third wired communication unit, and the wireless communication unit.

[0022] A communication control method according to one aspect is a communication control method executed by a communication control device having a first wired communication unit having a wired communication function, a second wired communication unit having a wired communication function, a third wired communication unit having a wired communication function and connected to a node, and a wireless communication unit having a wireless communication function capable of connecting to multiple wireless networks, and is characterized by including: an identification step of identifying whether adjacent devices connected to the first wired communication unit or the second wired communication unit via a wired network are communication control devices having the same function; and a communication control step of establishing communication via a wireless network with another communication control device, and further executing a bridge function to forward communication frames to an appropriate destination between the first wired communication unit, the second wired communication unit, the third wired communication unit, and the wireless communication unit.

[0023] A communication control program according to one aspect is characterized in that it causes a communication control device having a first wired communication unit having a wired communication function, a second wired communication unit having a wired communication function, a third wired communication unit having a wired communication function and connected to a node, and a wireless communication unit having a wireless communication function capable of connecting to multiple wireless networks to perform a process of identifying whether an adjacent device connected to the first wired communication unit or the second wired communication unit via a wired network is a communication control device having the same function, establishing communication via the wireless network with another communication control device, and further performing a bridge function that forwards communication frames to an appropriate destination between the first wired communication unit, the second wired communication unit, the third wired communication unit, and the wireless communication unit.

[0024] According to one aspect, a communication control system includes a first node, a first communication control device, a second node, and a second communication control device, wherein the first communication control device includes a first wired communication unit having a wired communication function, a second wired communication unit having a wired communication function, a third wired communication unit having a wired communication function and connected to the first node, a first wireless communication unit having a wireless communication function connectable to a plurality of wireless networks, and when the first wired communication unit or the second wired communication unit is connected to the second communication control device via a wired network, establishes communication with the second communication control device via a wireless network, and transmits a frame transmitted from the first communication control device to the second communication control device via both the wired network and the wireless network. and a first communication control unit that transmits frames to the second communication control device, wherein the second communication control device has a fourth wired communication unit having a wired communication function, a fifth wired communication unit having a wired communication function, a sixth wired communication unit having a wired communication function and connected to the second node, a second wireless communication unit having a wireless communication function that can connect to multiple wireless networks, and a second communication control unit that, when the fourth wired communication unit or the fifth wired communication unit is connected to the first communication control device via the wired network, establishes communication with the first communication control device via the wireless network and transmits frames to be transmitted from the second communication control device to the first communication control device via both the wired network and the wireless network. [Effects of the Invention]

[0025] According to one embodiment, redundancy in a communication network can be easily achieved. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a diagram illustrating an example of the configuration of a communication control system according to a first embodiment. [Figure 2] 1 is a diagram illustrating an example of the configuration of a communication control system according to a first embodiment. [Figure 3] 1 is a diagram illustrating an example of the configuration of a communication control system according to a first embodiment. [Figure 4] 1 is a diagram illustrating an example of the configuration of a communication control system according to a first embodiment. [Figure 5] 1 is a diagram illustrating an example of the configuration of a communication control device according to a first embodiment. [Figure 6] 10 is a flowchart showing a flow of processing by the communication control device. [Figure 7] 10 is a flowchart showing a flow of processing by the communication control device. [Figure 8] FIG. 2 is a diagram illustrating an example of a hardware configuration. [Figure 9] FIG. 1 illustrates a conventional communication control system. [Figure 10] FIG. 1 illustrates a conventional communication control system. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, embodiments of a communication control device, a communication control method, a communication control program, and a communication control system disclosed in the present application will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments described here. Furthermore, identical elements are given the same reference numerals, and redundant explanations will be omitted as appropriate. Furthermore, each embodiment can be combined as appropriate within a range that does not cause contradictions.

[0028] The configuration of the communication control system according to the first embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing an example of the configuration of the communication control system according to the first embodiment.

[0029] 1, the communication control system 1 includes a switch 11, a node 21, a node 22, a node 23, and a node 24. Each node may be connected to a sensor and an actuator.

[0030] Here, a node is a device that processes information and communicates. A node may also be referred to as a computer. A sensor transmits a frame indicating a detected sensor value or a detection result based on the sensor value to the node using a predetermined communication protocol.

[0031] For example, the sensors and actuators are provided in a plant, such as an oil plant, a petrochemical plant, a chemical plant, or a gas plant, which produces products such as LNG (liquefied natural gas), resins (plastics, nylon, etc.), and chemical products.

[0032] The plant also includes factory facilities, machinery facilities, production facilities, power generation facilities, storage facilities, wellhead facilities for extracting oil, natural gas, etc. The plant is also equipped with equipment for producing products.

[0033] Sensors acquire information about the state of the plant. For example, sensors include temperature sensors, pH sensors, speed sensors, acceleration sensors, air pressure sensors, gas concentration sensors, devices that detect the opening of valves, devices that detect the state of switches (on or off), etc. Actuators drive valves, etc.

[0034] Also, for example, node 21 transmits a frame acquired from a sensor to node 22. Node 22 performs arithmetic processing. Node 22 also transmits the results of the arithmetic processing (control signals, etc.) to an actuator, etc., connected to node 23 via node 23.

[0035] The configuration and operation of the nodes included in the communication control system 1 are not limited to those described here. The nodes included in the communication control system 1 may be any nodes that communicate data with each other.

[0036] Node 21 includes a wired communication unit 211. The wired communication unit 211 is connected to communication control device 51. Node 22 includes a wired communication unit 221. The wired communication unit 221 is connected to communication control device 52. Node 23 includes a wired communication unit 231. The wired communication unit 231 is connected to communication control device 53. Node 24 includes a wired communication unit 241 and a wired communication unit 242. The wired communication unit 241 is connected to communication control device 53. The wired communication unit 242 is connected to switch 11.

[0037] In this way, node 21, node 22, and node 23 each include one wired communication unit. Each wired communication unit may include, for example, an Ethernet port to which a LAN (Local Area Network) cable is connected. Node 21, node 22, and node 23 are devices with one communication port, i.e., 1-port DEVs (Devices). On the other hand, node 24 is a 2-port DEV (Device) incorporating a bridge with two communication ports.

[0038] Since nodes are installed in narrow spaces or places with limited available space, there may be constraints such as miniaturization, weight reduction, and simplified configuration, etc. For this reason, a two-port DEV such as node 24 may not always be realized, and nodes may be limited to a one-port DEV.

[0039] According to the communication control device 51, communication control device 52, and communication control device 53 of this embodiment, even if a node has only one communication port, a redundant network configuration can be easily realized between the nodes, at least between the communication control device 51, communication control device 52, and communication control device 53.

[0040] The communication control device 51 has a first wired communication unit 511, a second wired communication unit 512, a third wired communication unit 513, and a wireless communication unit 514. The first wired communication unit 511 is connected to the switch 11. The second wired communication unit 512 is connected to a wired communication unit 521 of the communication control device 52. The third wired communication unit 513 is connected to a wired communication unit 211 of the node 21.

[0041] The communication control device 52 has a wired communication unit 521, a wired communication unit 522, a wired communication unit 523, and a wireless communication unit 524. The wired communication unit 521 is connected to a second wired communication unit 512 of the communication control device 51. The wired communication unit 522 is connected to a wired communication unit 531 of the communication control device 53. The wired communication unit 523 is connected to a wired communication unit 221 of the node 22.

[0042] The communication control device 53 has a wired communication unit 531, a wired communication unit 532, a wired communication unit 533, and a wireless communication unit 534. The wired communication unit 531 is connected to the wired communication unit 522 of the communication control device 52. The wired communication unit 532 is connected to the wired communication unit 241 of the node 24. The wired communication unit 533 is connected to the switch 11.

[0043] Each wired communication unit is, for example, a wired communication module. The wired communication module is a module having a communication function corresponding to a predetermined wired communication protocol, such as an Ethernet module, a Fibre Channel module, or a USB module. The wireless communication unit is a wireless communication module. The wireless communication module is a module having a communication function corresponding to a predetermined wireless communication protocol, such as a Wi-Fi (registered trademark) module, a Bluetooth (registered trademark) module, or an LPWA (Low Power Wide Area) module.

[0044] The nodes and the communication control units may be connected via USB (Universal Serial Bus) instead of Ethernet. In this case, the wired communication unit 211, the third wired communication unit 513, the wired communication unit 221, the wired communication unit 523, the wired communication unit 231, and the wired communication unit 533 each include a USB port. Furthermore, the communication control device 51 can receive power from the node 21 via the USB port.

[0045] The following describes the operations of the communication control device 51, the communication control device 52, and the communication control device 53. Since the communication control device 51, the communication control device 52, and the communication control device 53 have the same functions, the communication control device 51, the communication control device 52, and the communication control device 53 in the following description may be interchanged as appropriate. Processing similar to that performed between the communication control device 51 and the communication control device 52 is performed between the communication control device 52 and the communication control device 53.

[0046] 1, a communication control device 51 is connected to a switch 11 and a node 21 via a wired network. A communication control device 52 is connected to a node 22 via a wired network. The communication control device 51 and the communication control device 52 are connected to a wired network including the switch 11. Note that devices not shown may be further connected to the wired network.

[0047] The communication control device 51 identifies whether adjacent devices connected via a wired network to the first wired communication unit 511 or the second wired communication unit 512 are communication control devices having the same function. For example, the communication control device 51 identifies each other by exchanging identification information indicating that the adjacent communication control devices 52 are specific communication control devices having the same function.

[0048] The identification information is, for example, a MAC address or a device ID previously set in the device. Information exchange between adjacent devices is performed using a protocol such as LLDP (Link Layer Discovery Protocol). For example, the communication control device 51 identifies the communication control device 52 having a MAC address starting with a specific value or a device ID having a specific pattern as a communication control device having the same function.

[0049] Furthermore, at this time, the communication control device 52 is assumed to have identified the communication control device 51 as another communication control device that satisfies the conditions using the same method as the communication control device 51. In this case, the communication control device 51 establishes communication with the identified communication control device via a wireless network. When the communication control device 51 identifies the communication control device 52 as a communication control device that satisfies the conditions, the communication control device 51 establishes wireless communication between the wireless communication unit 514 and the wireless communication unit 524.

[0050] For example, the communication control device 51 establishes communication with the communication control device 52 by performing Bluetooth pairing. Also, for example, the communication control device 51 establishes communication with the communication control device 52 by using itself as a WiFi access point or through a peer-to-peer connection.

[0051] As a result, as shown in Fig. 1, communication control device 51 and communication control device 52 are connected by both a wired network (solid line in Fig. 1) and a wireless network (dotted line in Fig. 1). By similar processing, communication control device 52 and communication control device 53 are connected by both a wired network and a wireless network. As a result, a redundant network configuration can be easily realized at least between communication control device 51, communication control device 52, and communication control device 53.

[0052] Furthermore, the communication control device 51 transmits a frame sent from node 21 addressed to node 22 via both a route via the wired network and a route via the wireless network. When the communication control device 52 receives the same frame from the communication control device 51 via both the wired network and the wireless network, it forwards the frame that was received earlier to node 22 and discards the frame that was received later. At this time, the same processing is also performed when transmitting a frame in the opposite direction, that is, when a frame is transmitted from node 22 to node 21 via the communication control device 52 and communication control device 51. As a result, even if one of the frames does not arrive correctly, time-consuming processing such as retransmitting the frame or switching from the abnormal network to the normal network is not required.

[0053] Such frame forwarding and discarding by the communication control system 1 may be achieved using a method such as IEEE 802.1CB (Frame Replication and Elimination for Reliability).

[0054] For example, as shown in Fig. 2, even if the wired connection between the communication control device 51, the communication control device 52, and the communication control device 53 is lost (for example, when the communication cable is unplugged), the wireless communication between the communication control device 51, the communication control device 52, and the communication control device 53 is not interrupted. Fig. 2 is a diagram showing an example of the configuration of the communication control system according to the first embodiment.

[0055] Even when a new node is added, the communication control system 1 can reconstruct a network including the node. The operation of the communication control system 1 when a node is added will be described with reference to Figures 3 and 4. Figures 3 and 4 are diagrams showing an example of the configuration of a communication control system according to the first embodiment.

[0056] 3, consider a case where a node 25 is added to the communication control system 1 together with a communication control device 55. The node 25 has a wired communication unit 251. The communication control device 55 has a wired communication unit 551, a wired communication unit 552, a wired communication unit 553, and a wireless communication unit 554. The communication control device 55 has the same functions as the communication control device 51.

[0057] The wired communication unit 251 of the node 25 is connected to the wired communication unit 553 of the communication control device 55. The wired communication unit 551 of the communication control device 55 is connected to the second wired communication unit 512 of the communication control device 51. The wired communication unit 552 of the communication control device 55 is connected to the wired communication unit 521 of the communication control device 52.

[0058] Here, the communication control device 55 performs the same process as the above-described communication control device 51. That is, when the wired communication unit 551 or the wired communication unit 552 is connected to a wired network, the communication control device 55 identifies that adjacent devices connected via the wired network are communication control devices having the same function.

[0059] For example, the communication control device 55 identifies the communication control device 51 and the communication control device 52 as communication control devices having the same function using predetermined identification information. Similarly, the communication control device 51 and the communication control device 52 also perform processing to identify adjacent devices as communication control devices having the same function, triggered by connection to the communication control device 55 via a wired network.

[0060] As a result, a redundant network is configured as shown in Fig. 4. In the example of Fig. 4, a redundant network is configured between communication control device 51, communication control device 55, communication control device 52, and communication control device 53.

[0061] In this way, after communication via the wireless network is established between the second wired communication unit 512 and the communication control device 52 connected via the wired network, the communication control device 51 continues communication with the communication control device 52 via the wireless network even when the second wired communication unit 512 and the communication control device 55 are connected. Similarly, after communication via the wireless network is established between the wired communication unit 521 and the communication control device 51 connected via the wired network, the communication control device 52 continues communication with the communication control device 51 via the wireless network even when the wired communication unit 521 and the communication control device 55 are connected. At this time, the communication control device 51 and the communication control device 52 do not communicate via the communication control device 55, and only temporary communication is performed between the communication control device 51 and the communication control device 55 and between the communication control device 52 and the communication control device 55. If the communication control device 55 is identified as a communication control device having the same function through this temporary communication, communication via the wireless network is established between the communication control device 51 and the communication control device 55 and between the communication control device 52 and the communication control device 55. Furthermore, after the communication control device 51 and the communication control device 52 are connected to the communication control device 55, the communication via the wireless network established between the communication control device 51 and the communication control device 52 is disconnected before establishing communication via the wireless network. This makes it possible to add a new communication control device 55 between the communication control device 51 and the communication control device 52 while maintaining wireless communication between the communication control device 51 and the communication control device 52 without disconnecting it.

[0062] The configuration of the communication control device 51 will be described with reference to Fig. 5. Fig. 5 is a diagram showing an example of the configuration of the communication control device according to the first embodiment. Note that the configurations of the communication control device 52, communication control device 53, and communication control device 55 are the same as the configuration of the communication control device 51.

[0063] 5, communication control device 51 has first wired communication unit 511, second wired communication unit 512, third wired communication unit 513, wireless communication unit 514, storage unit 515, and control unit 516. Note that the parts such as "first" and "second" attached to the wired communication units may be omitted as appropriate.

[0064] The first wired communication unit 511 and the second wired communication unit 512 have a wired communication function. The third wired communication unit 513 has a wired communication function and is connected to the node 21. The wireless communication unit 514 has a wireless communication function.

[0065] The storage unit 515 stores various data and various programs executed by the control unit 516. For example, the storage unit 515 is a storage device such as an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a flash memory. The storage unit 515 stores, as necessary, various data generated in the processes executed by the communication control device 51, such as data obtained in the process of the control unit 516 executing various processes and processing results obtained by executing the various processes.

[0066] The control unit 516 is a processing unit that controls the entire communication control device 51. The control unit 516 is an arithmetic unit such as a CPU (Central Processing Unit) equipped with a processor, a microcomputer, etc. The control unit 516 has an identification unit 5161 and a communication control unit 5162.

[0067] When the first wired communication unit 511 or the second wired communication unit 512 is connected to a wired network, the identification unit 5161 identifies whether adjacent devices connected via the wired network are communication control devices having the same function. For example, the identification unit 5161 identifies whether the adjacent devices are communication control devices having the same function based on predetermined identification information.

[0068] 1, the communication control device 52 identifies the communication control device 51 and the communication control device 53. In this case, the communication control device 52 may store identification information that can identify both the communication control device 51 and the communication control device 53.

[0069] The communication control unit 5162 establishes communication with other communication control devices via a wireless network. The communication control unit 5162 also has a bridge function for transferring communication frames to appropriate destinations between the first wired communication unit 511, the second wired communication unit 512, the third wired communication unit 513, and the wireless communication unit 514, and further, when the same frame is received from other communication control devices via both the wired network and the wireless network, the communication control unit 5162 transfers the frame that was received earlier to the node 21 and discards the frame that was received later.

[0070] Furthermore, when the specifying unit 5161 specifies a plurality of communication control devices, the communication control unit 5162 establishes communication with each of the plurality of communication control devices via a wireless network.

[0071] The process of establishing a wireless network by the communication control device will be described with reference to Fig. 6. Fig. 6 is a flowchart showing the flow of the process by the communication control device.

[0072] 6, first, the communication control device 51 waits (step S101) until a trigger occurs while connected to the wired network (step S101, No). The trigger may be connection to the wired network, the passage of a certain time since being connected to the wired network, or a manual operation.

[0073] When a trigger occurs (step S101, Yes), the communication control device 51 identifies whether adjacent devices connected via a wired network are communication control devices having the same functions (step S102).

[0074] If the adjacent device does not satisfy the conditions (if it is not a communication control device with the same functions) (step S103, No), the communication control device 51 continues communication only via the wired network in the corresponding wired communication unit. Alternatively, the communication control device 51 may reset the trigger and return to the start. On the other hand, if the adjacent device satisfies the conditions (if it is a communication control device with the same functions) (step S103, Yes), the communication control device 51 establishes a wireless network with the communication control device that satisfies the conditions (step S104).

[0075] The process of transferring a frame by the communication control device will be described with reference to Fig. 7. Fig. 7 is a flowchart showing the flow of the process by the communication control device.

[0076] As shown in FIG. 7, first, the communication control device 51 receives a frame from either a wired network or a wireless network (step S201).

[0077] If the information identifying the received frame is stored in the storage unit 515 (step S202, Yes), the communication control device 51 deletes the stored information and discards the received frame (step S203). On the other hand, if the information identifying the received frame is not stored in the storage unit 515 (step S202, No), the communication control device 51 stores the information identifying the received frame in the storage unit 515 and forwards the received frame to an appropriate destination (step S204). The information identifying the frame is, for example, a hash value calculated from the entire frame or a sequence number intentionally inserted in the frame by an adjacent communication control device, and if the information intentionally inserted in the frame is used, it is removed from the frame before forwarding the frame.

[0078] Discarding a frame may mean not forwarding the received frame, not storing the received frame in memory, or actively deleting the received frame.

[0079] As described above, the first wired communication unit 511 and the second wired communication unit 512 have a wired communication function. The third wired communication unit 513 has a wired communication function and is connected to the node 21. The wireless communication unit 514 has a wireless communication function that allows connection to multiple wireless networks. When the first wired communication unit 511 or the second wired communication unit 512 is connected to a wired network, the identification unit 5161 identifies whether adjacent devices connected via the wired network are communication control devices having the same function. The communication control unit 5162 establishes communication with other communication control devices via the wireless network. This makes it possible to easily achieve redundancy in the main paths of the communication network even if each node has only one communication port.

[0080] Furthermore, the identifying unit 5161 identifies other communication control devices identified by predetermined identification information. This allows the communication control device 51 to verify whether the adjacent devices satisfy the condition that they are communication control devices having the same function, and to identify them reliably.

[0081] Furthermore, when the communication control unit 5162 receives the same frame from other communication control devices via both the wired network and the wireless network, it transfers the frame that was received earlier to the node 21 and discards the frame that was received later. As a result, even if one of the frames does not arrive correctly, the communication control unit 5162 does not need to perform time-consuming processes such as retransmitting the frame or switching from an abnormal network to a normal network, thereby achieving stable communication operation.

[0082] [system] The information including the processing procedures, control procedures, specific names, various frames and parameters shown in the above documents and drawings can be changed arbitrarily unless otherwise specified.

[0083] Furthermore, the components of each device shown in the figure are conceptual functional components and do not necessarily have to be physically configured as shown in the figure. In other words, the specific form of distribution and integration of each device is not limited to that shown in the figure. In other words, all or part of them can be functionally or physically distributed and integrated in any unit depending on various loads, usage conditions, etc.

[0084] Furthermore, all or any part of the processing functions performed by each device may be realized by a CPU and a program analyzed and executed by the CPU, or may be realized as hardware using wired logic.

[0085] [Hardware] Next, a description will be given of an example of the hardware configuration of the communication control device 51. Fig. 8 is a diagram illustrating an example of the hardware configuration. The communication control device 51 and the communication control device 52 have the same hardware configuration as the communication control device 500 in Fig. 8.

[0086] 8, the communication control device 500 includes a communication device 500a, an HDD 500b, a memory 500c, and a processor 500d. The components shown in FIG. 8 are connected to each other via a bus or the like.

[0087] The communication device 500a is a network interface card or the like, and communicates with external devices and equipment. The HDD 500b stores programs and data that operate the functions shown in FIG.

[0088] The processor 500d reads out a program that executes the same processes as the respective processing units shown in FIG. 5 from the HDD 500b or the like and loads the program into the memory 500c, thereby operating a process that executes the respective functions described in FIG. 5 or the like. For example, this process executes the same functions as the respective processing units of the communication control device 51. Specifically, the processor 500d reads out a program having the same functions as the identification unit 5161 and the communication control unit 5162 from the HDD 500b or the like. Then, the processor 500d executes a process that executes the same processes as the identification unit 5161 and the communication control unit 5162.

[0089] In this way, the communication control device 51 operates as a communication control device that executes a communication control method by reading and executing a program. The communication control device 51 can also realize functions similar to those of the above-described embodiment by reading the program from a recording medium using a medium reader and executing the read program. Note that the program in these other embodiments is not limited to being executed by the communication control device 51. For example, the present invention can also be applied in the same way to cases where another computer or server executes the program, or where these execute the program in cooperation with each other.

[0090] This program can be distributed via a network such as the Internet. In addition, this program can be recorded on a computer-readable recording medium such as a hard disk, a flexible disk (FD), a CD-ROM, a magneto-optical disk (MO), or a digital versatile disk (DVD), and can be executed by being read from the recording medium by a computer.

[0091] Some examples of combinations of the disclosed technical features are set out below.

[0092] (1) a first wired communication unit having a wired connection function; a second wired communication unit having a wired connection function; a third wired communication unit having a wired connection function and connected to the node; a wireless communication unit having a wireless communication function that can connect to a plurality of wireless networks; an identification unit that identifies whether adjacent devices connected to the first wired communication unit or the second wired communication unit via a wired network are communication control devices having the same function; a communication control unit that establishes communication with another communication control device via a wireless network and has a bridge function that transfers communication frames to appropriate destinations among the first wired communication unit, the second wired communication unit, the third wired communication unit, and the wireless communication unit; A communication control device comprising: (2) The identifying unit identifies whether adjacent devices are communication control devices having the same function based on predetermined identification information. The communication control device according to (1) above. (3) The identification unit identifies another communication control device having a MAC address starting with a specific value or another communication control device having a device ID having a specific pattern as a communication control device having the same function. The communication control device according to (1) or (2) is characterized in that: (4) When the communication control unit receives the same frame from other communication control devices via both the wired network and the wireless network, the communication control unit transfers the frame that was received first to an appropriate destination and discards the frame that was received later. The communication control device according to any one of (1) to (3). (5) The communication control unit establishes communication with the third communication control device via the wireless network when the second wired communication unit and a third communication control device are connected and the identification unit identifies the third communication control device after communication via the wireless network is established between the second wired communication unit and a second communication control device connected via the wired network. The communication control device according to any one of (1) to (4). (6) The communication control unit disconnects the communication over the wireless network established with the second communication control device before establishing communication over the wireless network with the third communication control device after the second wired communication unit and the third communication control device are connected. The communication control device according to (4) above. (7) a first wired communication unit having a wired communication function; a second wired communication unit having a wired communication function; a third wired communication unit having a wired communication function and connected to the node; a wireless communication unit having a wireless communication function that can connect to a plurality of wireless networks; A communication control method executed by a communication control device having a specifying step of specifying whether adjacent devices connected to the first wired communication unit or the second wired communication unit via a wired network are communication control devices having the same function; a communication control step of establishing communication with another communication control device via a wireless network, and further executing a bridge function of transferring communication frames to appropriate destinations among the first wired communication unit, the second wired communication unit, the third wired communication unit, and the wireless communication unit; A communication control method comprising: (8) a first wired communication unit having a wired communication function; a second wired communication unit having a wired communication function; a third wired communication unit having a wired communication function and connected to the node; a wireless communication unit having a wireless communication function that can connect to a plurality of wireless networks; A communication control device having Identifying whether adjacent devices connected to the first wired communication unit or the second wired communication unit via a wired network are communication control devices having the same function; Establishes communication with another communication control device via a wireless network, and further executes a bridge function for transferring communication frames to appropriate destinations among the first wired communication unit, the second wired communication unit, the third wired communication unit, and the wireless communication unit. A communication control program that causes a process to be executed. (9) A communication control system having a first node, a first communication control device, a second node, and a second communication control device, The first communication control device a first wired communication unit having a wired communication function; a second wired communication unit having a wired communication function; a third wired communication unit having a wired communication function and connected to the first node; a first wireless communication unit having a wireless communication function connectable to a plurality of wireless networks; a first communication control unit that, when the first wired communication unit or the second wired communication unit is connected to the second communication control device via a wired network, establishes communication with the second communication control device via a wireless network, and transmits a frame transmitted from the first communication control device to the second communication control device via both the wired network and the wireless network; and The second communication control device a fourth wired communication unit having a wired communication function; a fifth wired communication unit having a wired communication function; a sixth wired communication unit having a wired communication function and connected to the second node; a second wireless communication unit having a wireless communication function connectable to a plurality of wireless networks; a second communication control unit that, when the fourth wired communication unit or the fifth wired communication unit is connected to the first communication control device via the wired network, establishes communication with the first communication control device via the wireless network, and transmits a frame transmitted from the second communication control device to the first communication control device via both the wired network and the wireless network; A communication control system comprising: (10) when the first communication control unit receives the same frame from the second communication control device via both the wired network and the wireless network, the first communication control unit transfers the frame that was received earlier to an appropriate destination and discards the frame that was received later; When the second communication control unit receives the same frame from the first communication control device via both the wired network and the wireless network, the second communication control unit forwards the frame that was received first to an appropriate destination and discards the frame that was received later. The communication control system according to (9) above. [Explanation of symbols]

[0093] 1. Communication Control System 11 Switch 21, 22, 23, 24, 25 nodes 51, 52, 53, 55 Communication control device 211, 221, 231, 241, 242, 521, 522, 523, 531, 532, 533, 551, 552, 553 Wired Communications Department 511 First Wired Communication Department 512 Second Wired Communication Unit 513 Third Wired Communications Department 514, 524 Radio Communication Department 515 Storage section 516 Control Unit 5161 Specific part 5162 Communication Control Unit

Claims

1. a first wired communication unit having a wired connection function; a second wired communication unit having a wired connection function; a third wired communication unit having a wired connection function and connected to the node; a wireless communication unit having a wireless communication function capable of connecting to a plurality of wireless networks; a determination unit that determines whether adjacent devices connected to the first wired communication unit or the second wired communication unit via a wired network are communication control devices having the same function; a communication control unit that establishes communication with another communication control device via a wireless network and has a bridge function that transfers a communication frame to an appropriate destination among the first wired communication unit, the second wired communication unit, the third wired communication unit, and the wireless communication unit; A communication control device comprising:

2. The identification unit identifies whether adjacent devices are communication control devices having the same function based on predetermined identification information.

2. The communication control device according to claim 1 .

3. The identification unit identifies another communication control device having a MAC address starting with a specific value or another communication control device having a device ID having a specific pattern as a communication control device having the same function.

2. The communication control device according to claim 1 .

4. When the communication control unit receives the same frame from another communication control device via both the wired network and the wireless network, the communication control unit transfers the frame that was received first to an appropriate destination and discards the frame that was received later.

2. The communication control device according to claim 1 .

5. The communication control unit establishes communication with the third communication control device via the wireless network when the second wired communication unit and a third communication control device are connected and the identification unit identifies the third communication control device after communication via the wireless network is established between the second wired communication unit and a second communication control device connected via the wired network.

2. The communication control device according to claim 1 .

6. The communication control unit disconnects the communication via the wireless network established with the second communication control device before establishing communication with the third communication control device via the wireless network after the second wired communication unit and the third communication control device are connected.

6. The communication control device according to claim 5,

7. a first wired communication unit having a wired communication function; a second wired communication unit having a wired communication function; a third wired communication unit having a wired communication function and connected to the node; a wireless communication unit having a wireless communication function capable of connecting to a plurality of wireless networks; A communication control method executed by a communication control device having a step of determining whether adjacent devices connected to the first wired communication unit or the second wired communication unit via a wired network are communication control devices having the same function; a communication control step of establishing communication with another communication control device via a wireless network, and further executing a bridge function of transferring a communication frame to an appropriate destination among the first wired communication unit, the second wired communication unit, the third wired communication unit, and the wireless communication unit; A communication control method comprising:

8. a first wired communication unit having a wired communication function; a second wired communication unit having a wired communication function; a third wired communication unit having a wired communication function and connected to the node; a wireless communication unit having a wireless communication function capable of connecting to a plurality of wireless networks; A communication control device having Identifying whether adjacent devices connected to the first wired communication unit or the second wired communication unit via a wired network are communication control devices having the same function; Establish communication with another communication control device via a wireless network, and further execute a bridge function for transferring a communication frame to an appropriate destination among the first wired communication unit, the second wired communication unit, the third wired communication unit, and the wireless communication unit. A communication control program for executing a process.

9. A communication control system having a first node, a first communication control device, a second node, and a second communication control device, The first communication control device a first wired communication unit having a wired communication function; a second wired communication unit having a wired communication function; a third wired communication unit having a wired communication function and connected to the first node; a first wireless communication unit having a wireless communication function connectable to a plurality of wireless networks; a first communication control unit that, when the first wired communication unit or the second wired communication unit is connected to the second communication control device via a wired network, establishes communication with the second communication control device via a wireless network, and transmits a frame transmitted from the first communication control device to the second communication control device via both the wired network and the wireless network; having The second communication control device includes: a fourth wired communication unit having a wired communication function; a fifth wired communication unit having a wired communication function; a sixth wired communication unit having a wired communication function and connected to the second node; a second wireless communication unit having a wireless communication function connectable to a plurality of wireless networks; a second communication control unit that, when the fourth wired communication unit or the fifth wired communication unit is connected to the first communication control device via the wired network, establishes communication with the first communication control device via the wireless network, and transmits a frame transmitted from the second communication control device to the first communication control device via both the wired network and the wireless network; A communication control system comprising:

10. when the first communication control unit receives the same frame from the second communication control device via both the wired network and the wireless network, the first communication control unit transfers the frame that was received earlier to an appropriate destination and discards the frame that was received later; When the second communication control unit receives the same frame from the first communication control device via both the wired network and the wireless network, the second communication control unit transfers the frame that was received first to an appropriate destination and discards the frame that was received later.

10. The communication control system according to claim 9.

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