JP2008193183A - Communication equipment and communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently achieve a bridge function in a gateway for connecting a mesh network to a non-mesh network by a minimum change. <P>SOLUTION: When a packet received in a transmission part 130 is a packet of a specific sort (e.g. a DHCP packet or an ARP packet), an address of a non-mesh node of a transmission source of the packet is registered in a representation response table 120. When receiving a route request from a mesh node, a route control part 150 generates a route by performing representation response or notifying the mesh node about the address of the non-mesh node. When a destination address of a data packet received from the mesh node has been already registered in the representation response table 120, a data processing part 160 transfers the data packet to the non-mesh node by the bridge function. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a communication system, and more particularly, to a communication system including a communication device that connects different networks, a processing method therefor, and a program that causes a computer to execute the method.

  The mesh network (ad hoc network) is a technology that is being standardized in the Internet Engineering Task Force (IETF) MANET (Mobile Ad-hoc Network) and IEEE (Institute of Electrical and Electronic Engineers) 802.11s. In this mesh network, overall control by a specific access point is not performed, and a network is formed by arbitrary wireless communication devices operating as wireless terminals being autonomously distributed and performing asynchronous wireless communication directly.

  In this mesh network, communication with a wireless communication device existing in a range where direct radio waves do not reach is realized by passing through another wireless communication device (so-called multi-hop communication). A route passing through another wireless communication device up to the destination wireless communication device is controlled by a route control protocol. A wireless communication device belonging to a mesh network manages a route to another wireless communication device using a table or the like. A function for connecting to such a mesh network is referred to as a mesh function.

  On the other hand, some other communication devices may not have such a mesh function. A communication device that does not have a mesh function can communicate with a wireless communication device that belongs to a mesh network via a communication device called a gateway. The gateway has a bridge function that realizes a bridge between the mesh network and the other network (non-mesh network), thereby enabling communication between the two without going through the network layer as the third layer.

As a method of using such a gateway, for example, a communication system has been proposed in which the address of the gateway is notified to each station in the network in advance, and then the destination address is rewritten to the gateway address at the relay station that has received the packet. (For example, refer to Patent Document 1).
Japanese Patent Laying-Open No. 2005-236767 (FIG. 5)

  In the prior art described above, in order to connect to an external network, the destination address is rewritten to the gateway address in the relay station that has received the packet. However, in order to perform such rewriting in the relay station of the mesh network, it is necessary to significantly change the mesh function in all the wireless communication devices in the mesh network.

  The present invention has been made in view of such circumstances, and an object thereof is to efficiently realize a bridge function in a gateway connecting a mesh network and a non-mesh network with a minimum change.

  The present invention has been made to solve the above problems, and a first aspect of the present invention is a communication device that connects a first network and a second network, and belongs to the first network. An identifier storage unit that holds an identifier of another communication device and an identifier of the communication device that is the transmission source when the data that is transmitted from the other communication device that belongs to the first network is a predetermined type of data Is transmitted to the identifier storage means, the path generation means for generating a path to the communication apparatus in which the identifier is held in the identifier storage means, and another communication apparatus belonging to the second network. When the identifier of the destination communication device is held in the identifier storage means for the original data, the data to be transmitted to the first network is stored. A communication apparatus characterized by comprising a processing unit. Thus, by storing the identifier of the communication device that is the transmission source of a predetermined type of data from the communication device belonging to the first network in the identifier storage unit, the data from the communication device belonging to the second network is stored. When the destination is held in the identifier storage unit, the data is transmitted to the first network.

  In the first aspect, in the second network, each communication device communicates with another communication device existing outside the range of the wireless communication through a route via a neighboring communication device. It may be. That is, the second network can operate as a mesh network.

  In the first aspect, the predetermined type of data may include a request for acquiring an identifier of a communication device. For example, a broadcast packet that is likely to flow at the start of communication, such as an ARP packet or a DHCP packet, can be assumed. By limiting to a specific type of packet, the load for managing the identifier storage means is reduced.

  In the first aspect, the route generation means holds the identifier of the destination communication device in the identifier storage means for a route search request whose source is another communication device belonging to the second network. If it is, the response to the route search request may be made instead of the destination communication device. As a result, the reactive route control protocol has an effect of generating a route to another communication device belonging to the first network.

  In the first aspect, the path generation unit may notify the communication device identifier held in the identifier storage unit to another communication device belonging to the second network. As a result, the proactive route control protocol has an effect of generating a route to another communication device belonging to the first network.

  According to a second aspect of the present invention, there is provided a communication system including a first network, a second network, and a communication device that connects the first network and the second network, The communication device includes an identifier storage unit that holds an identifier of another communication device that belongs to the first network, and data that is transmitted from another communication device that belongs to the first network is a predetermined type of data. In this case, identifier management means for holding the identifier of the transmission source communication apparatus in the identifier storage means, path generation means for generating a path to the communication apparatus in which the identifier is held in the identifier storage means, If the identifier of the destination communication device is held in the identifier storage means for data originating from another communication device belonging to network No. 2 The data is a communication system characterized by comprising a data processing means for transmitting to the first network. Thus, by holding the identifier of the communication device that is the transmission source of the predetermined type of data from the communication device belonging to the first network of the communication system in the identifier storage unit, the communication device belonging to the second network When the destination of the data is held in the identifier storage means, the data is transmitted to the first network.

  According to a third aspect of the present invention, there is provided a path in a communication device that includes an identifier storage unit that connects the first network and the second network and holds identifiers of other communication devices belonging to the first network. In the control method, when the data whose source is another communication device belonging to the first network is a predetermined type of data, the identifier storage means holds the identifier of the source communication device An identifier management procedure, a route generation procedure for generating a route to a communication device in which the identifier is stored in the identifier storage means, and a destination of data destined for another communication device belonging to the second network A data processing procedure for transmitting the data to the first network when the identifier of the communication device is held in the identifier storage means; Is a program for causing to execute a routing method, or these steps, characterized in computers that. Thus, by storing the identifier of the communication device that is the transmission source of a predetermined type of data from the communication device belonging to the first network in the identifier storage unit, the data from the communication device belonging to the second network is stored. When the destination is held in the identifier storage unit, the data is transmitted to the first network.

  According to the present invention, it is possible to achieve an excellent effect that a bridge function in a gateway that connects a mesh network and a non-mesh network can be efficiently realized with a minimum change.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing an example of the overall configuration of a communication system in an embodiment of the present invention. In this communication system, a mesh network 280 and a wired network 290 that is a non-mesh network are connected by a gateway 210.

  In the mesh network 280, each of the mesh nodes 220, which are wireless communication devices, operates in an autonomously distributed manner, and performs route control using a mesh function. Therefore, the mesh network 280 does not have a control station like an infrastructure network. In this example, there are four mesh nodes 220 (M1 to M4) in the mesh network 280.

  In this figure, mesh nodes 220 connected by dotted lines can directly perform wireless communication. Communication between the mesh nodes 220 that cannot directly perform wireless communication is performed by multi-hop via another mesh node 220 or the gateway 210. Here, a one-to-one connection with another mesh node 220 (relay station) with which the mesh node 220 directly performs wireless communication is referred to as a link. A flow until the mesh node 220 reaches the partner station via the relay station is called a route.

  A non-mesh node 230 and a gateway 210 are connected to the wired network 290. Since the non-mesh node 230 does not have a mesh function, it cannot be directly connected to the mesh network 280. Therefore, the non-mesh node 230 is connected to the mesh network 280 via the gateway 210. In this example, there are four non-mesh nodes 230 (N1 to N4).

  As the wired network 290, for example, a local area network (LAN) can be used. Although the wired network 290 is illustrated here as an example of a non-mesh network, the present invention is not limited to this, and a wireless network such as a wireless LAN may be used.

  The gateway 210 is a communication device that is connected to the mesh network 280 and the wired network 290 and has a function of bridging mutual communication. In this example, one gateway 210 (G1) is shown, but as will be described later, a plurality of gateways 210 may be provided.

  FIG. 2 is a diagram illustrating a configuration example of the gateway 210 according to the embodiment of the present invention. The gateway 210 includes a route table 110, a proxy response table 120, a transmission unit 130, a proxy response table management unit 140, a route control unit 150, and a data processing unit 160.

  The route table 110 is a table that holds information about a route to a destination communication device. The routing table 110 holds the address of the communication device to be transmitted next corresponding to the address of the destination communication device (such as the mesh node 220). Therefore, by referring to this route table 110, it is possible to recognize to which communication device data should be transmitted next in multi-hop communication.

  The proxy response table 120 is a table that holds information regarding a communication device (non-mesh node 230) that should respond on behalf of the gateway 210. The proxy response table 120 holds the address of the non-mesh node 230. Accordingly, the non-mesh node 230 existing in the wired network 290 can be recognized by referring to the proxy response table 120.

  The transmission unit 130 performs physical transmission with other communication devices. Wireless transmission is performed to the mesh network 280. For this reason, an antenna (not shown) is connected. Further, wired transmission is performed to the wired network 290. For this reason, a cable connector (not shown) is connected.

  The proxy response table management unit 140 manages information related to communication devices held in the proxy response table 120. When the packet received by the transmission unit 130 is a specific type of packet, the proxy response table management unit 140 causes the proxy response table 120 to store the address of the non-mesh node 230 that is the transmission source of the packet.

  Here, the specific type of packet is, for example, a broadcast packet that is highly likely to flow at the start of communication, and a DHCP (Dynamic Host Configuration Protocol) packet or an ARP (Address Resolution Protocol) packet is assumed. A DHCP packet is a packet used when acquiring an IP address from a DHCP server. An ARP packet is a packet used when obtaining a MAC address from an IP address. As described above, the load for managing the proxy response table 120 can be reduced by limiting all the packets from the non-mesh node 230 to specific types of packets.

  The route controller 150 controls the route to the destination communication device. The route control unit 150 manages the route table 110 to determine a communication device to be transmitted next. Note that the generally proposed route control protocol includes (1) a reactive type that is created only when a route is required, (2) a proactive type that periodically maintains a route, and (3) both There is a hybrid type combining the above. The present invention is a technique applicable to any of these. For example, AODV (Ad-hoc On-demand Distance Vector) and DSR (Dynamic Source Routing) proposed by MANET (Mobile Ad-hoc NETwork) of IETF (Internet Engineering Task Force) are reactive, OLSR (Optimized Link). State Routing) and TBRPF (Topology Broadcast based on Reverse-Path Forwarding) are classified into proactive types.

  The data processing unit 160 receives a packet received by the transmission unit 130 as necessary and pulls it up to an upper layer (for example, a data link layer). In this upper layer, communication from the mesh network 280 to the wired network 290 is bridged.

  FIG. 3 is a diagram showing a configuration example of the route table 110 according to the embodiment of the present invention. The route table 110 holds fields of a destination node address 111, a next node address 112, and a hop number 113.

  The destination node address 111 is a field that holds an address for identifying a communication device as a destination. For example, a MAC address or an IP address can be used as this address.

  The next node address 112 is a field that holds an address for identifying the next communication device (next node) to reach the wireless communication device indicated by the destination node address 111. As this address, similarly to the destination node address 111, a MAC address, an IP address, or the like can be used.

  The hop count 113 is a field indicating the number of links to the communication device indicated by the destination node address 111, that is, the hop count.

  In this figure, information about four mesh nodes 220 (M1 to M4) is held as a specific example according to the example of FIG.

  FIG. 4 is a diagram showing a configuration example of the proxy response table 120 according to the embodiment of the present invention. This proxy response table 120 holds a proxy response address 121 that is the address of the non-mesh node 230 that should respond on behalf of the gateway 210.

  In this figure, as a specific example according to the example of FIG. 1, addresses of four non-mesh nodes 230 (N1 to N4) are held.

  FIG. 5 is a diagram showing an implementation example of the network hierarchy in the embodiment of the present invention. Here, a packet flow from the mesh node 220 to the non-mesh node 230 via the gateway 210 is shown.

  The mesh node 220 includes a network hierarchy of an application layer 325, a network layer 324, a mesh layer 323, a MAC layer, and a physical layer 321 from the upper layer. Data output from the application layer 325 is supplied from the network layer 324 to the mesh layer 323. The mesh node 220 performs path control between nodes by the mesh function in the mesh layer 323. The mesh node 220 is physically connected to the mesh network 280 by the MAC layer and the physical layer 321.

  The gateway 210 includes an application layer 315, a network layer 314, and a data link layer 313 from an upper layer, and mesh devices corresponding to a mesh layer and a MAC / physical layer connected to the mesh network 280 as lower layers. 311 and a network device 312 corresponding to the MAC / physical layer on the side connected to the wired network 290.

  The mesh device 311 is a lower layer having a mesh function, and is connected to the mesh network 280. The network device 312 is a lower layer that does not have a mesh function, and is connected to the wired network 290. The mesh device 311 and the network device 312 are connected by the data link layer 313, and packets received by the mesh device 311 can be transferred to the network device 312 by a bridge function. When the gateway 210 functions as a router, the network layer 314 performs communication using, for example, the IP (Internet Protocol) protocol.

  The non-mesh node 230 includes a network hierarchy of an application layer 335, a network layer 334, a MAC layer, and a physical layer 332 from the upper layer. That is, the non-mesh node 230 does not include a hierarchy corresponding to the mesh layer 323 in the mesh node 220. The MAC layer and the physical layer 332 are connected to the wired network 290 and transmit packets to the application layer 335 via the network layer 334.

  Next, the operation of the communication system according to the embodiment of the present invention will be described with reference to the drawings.

  FIG. 6 is a flowchart showing a processing procedure example of registration processing in the proxy response table 120 according to the embodiment of the present invention. Among the packets transmitted from the non-mesh node 230 in the gateway 210 (step S911), those whose destination is the broadcast address (step S912) and those whose destination is other than the gateway 210 (step S913) are determined by the data link layer 313. The network device 312 is bridged to the mesh device 311 and transferred to the mesh node 220 (step S916).

  At this time, if the received packet is a specific type of packet (in this example, a DHCP packet or an ARP packet) (step S914), the proxy response table management unit 140 sends the non-mesh node of the transmission source of the packet. The address 230 is registered in the proxy response table 120 (step S915).

  FIG. 7 is a flowchart showing an example of a processing procedure when the route creation processing in the embodiment of the present invention is applied to a reactive route control protocol. As an example of a reactive route control protocol, in AODV, a route request message (RREQ: Route REQuest) reaching a destination is broadcast by flooding in order to search for a route. Then, the destination node that received it returns a route reply message (RREP: Route Reply) to the source node by unicast. The route request message includes a destination address, a source address, the number of hops, a flag, and the like.

  In AODV, as a basic operation, only the destination node returns a route response message. However, in the case of a route request message in which the G flag (Gratuitous RREP flag) is on, an intermediate node may also reply. In the embodiment of the present invention, when the gateway 210 receives the route request message and the destination address in the route request message is registered in the proxy response table 120, the route request message may not be addressed to itself. Reply with route response message. Thereby, a route to the non-mesh node 230 is generated.

  That is, if the destination of the route request message is the gateway 210 itself (step S921) or if it is a node (non-mesh node 230) registered in the proxy response table 120 (step S922), the gateway 210 sends the route response message. A response is made (step S924). On the other hand, in the case of other route request messages, the gateway 210 transfers the route request message to another mesh node 220 by flooding (step S923).

  FIG. 8 is a flowchart showing an example of a processing procedure when the route creation processing in the embodiment of the present invention is applied to a proactive route control protocol. In the mesh network, each wireless communication apparatus transmits a message periodically in some form to indicate its existence. Here, such a periodic message is referred to as a hello message. In the case of the proactive type routing protocol, in the embodiment of the present invention, the contents of the proxy response table 120 are included in the hello message, so that the mesh node 220 recognizes the existence of the non-mesh node 230.

  That is, when a predetermined time at which a hello message should be transmitted has arrived (step S931), a hello message including the contents of the proxy response table 120 is transmitted (step S932). As a result, the contents of the proxy response table 120 are distributed to the mesh nodes 220.

  The mesh node 220 that has received the contents of the proxy response table 120 can add the non-mesh node 230 included in the proxy response table 120 to its route table. In this case, the next node address is set to be the same as the route to the gateway 210. However, the contents (copy) of the proxy response table 120 may be held as they are without being added to the route table and directly referred to. If the address of the destination communication device is held, it can be understood that it should be transmitted to the gateway 210.

  FIG. 9 is a flowchart showing a processing procedure example of data reception processing in the embodiment of the present invention. When a data packet is received, the standard for whether to perform reception processing that is raised to the upper layer, or to transfer or discard is usually whether the packet is addressed to itself. In the embodiment of the present invention, the reception process is also performed when the address of the destination communication device is registered in the proxy response table 120.

  That is, not only when the destination of the data packet is the gateway 210 itself (step S941), but also when the destination is registered in the proxy response table 120 (step S942), the reception process is performed (step S944), Pull up to the data link layer 313. At this time, if the destination is the gateway 210 itself, processing in the application layer 315 is performed. If the destination is not the gateway 210 itself, transfer from the network device 312 to the wired network 290 is performed by the bridge function in the data link layer 313. Is done.

  On the other hand, if the destination of the data packet is not the gateway 210 itself and the destination is not registered in the proxy response table 120, the data packet is transferred to the mesh network 280 by the mesh device 311; Discarded (step S943).

  As described above, according to the embodiment of the present invention, the address of the non-mesh node 230 is registered in the proxy response table 120, and the gateway 210 performs a proxy response to the route request from the mesh node 220. A route can be generated by notifying the mesh node 220 of the address of the mesh node 230. When the destination address of the data packet received by the gateway 210 is registered in the proxy response table 120, it can be transferred to the non-mesh node 230 by the bridge function of the gateway 210.

  In the embodiment of the present invention, the case where there is one gateway 210 is illustrated, but the present invention is not limited to this. For example, as shown in FIG. 10, when two gateways 210 (G1 and G2) are included in the mesh network 280, the gateway that reaches the shortest hop is automatically selected. For example, the data packet from the mesh node M6 reaches the gateway G2 via the mesh node M3 and reaches the non-mesh node 230 connected to the wired network 290.

  The embodiment of the present invention is an example for embodying the present invention and has a corresponding relationship with the invention-specific matters in the claims as shown below, but is not limited thereto. However, various modifications can be made without departing from the scope of the present invention.

  That is, in claims 1 to 7, the first network corresponds to the wired network 290, for example. The second network corresponds to the mesh network 280, for example. The identifier storage means corresponds to the proxy response table 120, for example. The identifier management means corresponds to the proxy response table management unit 140, for example. The route generation unit corresponds to the route control unit 150, for example. A data processing unit corresponds to the data processing unit 160, for example.

  Further, in claims 8 and 9, the first network corresponds to the wired network 290, for example. The second network corresponds to the mesh network 280, for example. The identifier storage means corresponds to the proxy response table 120, for example. An identifier management procedure corresponds to step S915, for example. The route generation procedure corresponds to, for example, step S924 or S932. The data processing procedure corresponds to, for example, step S944.

  The processing procedure described in the embodiment of the present invention may be regarded as a method having a series of these procedures, and a program for causing a computer to execute these series of procedures or a recording medium storing the program May be taken as

It is a figure which shows the example of whole structure of the communication system in embodiment of this invention. It is a figure which shows one structural example of the gateway 210 in embodiment of this invention. It is a figure which shows the example of 1 structure of the routing table 110 in embodiment of this invention. It is a figure which shows the example of 1 structure of the proxy response table 120 in embodiment of this invention. It is a figure which shows the implementation example of the network hierarchy in embodiment of this invention. It is a flowchart which shows the example of a process sequence of the registration process to the proxy response table 120 in embodiment of this invention. It is a flowchart which shows the example of a process sequence at the time of applying the route creation process in embodiment of this invention to a reactive type routing control protocol. It is a flowchart which shows the example of a process sequence at the time of applying the route creation process in embodiment of this invention to a proactive type route control protocol. It is a flowchart which shows the example of a process sequence of the data reception process in embodiment of this invention. It is a figure which shows the other example of the whole structure of the communication system in embodiment of this invention.

Explanation of symbols

110 Route Table 120 Proxy Response Table 130 Transmission Unit 140 Proxy Response Table Management Unit 150 Route Control Unit 160 Data Processing Unit 210 Gateway 220 Mesh Node 230 Non-mesh Node 280 Mesh Network 290 Wired Network

Claims (9)

A communication device for connecting a first network and a second network,
Identifier storage means for holding identifiers of other communication devices belonging to the first network;
An identifier management unit that holds an identifier of the transmission source communication device in the identifier storage unit when data having a transmission source of another communication device belonging to the first network is a predetermined type of data;
Route generating means for generating a route to the communication device in which the identifier is stored in the identifier storage means;
If the identifier of the destination communication device is held in the identifier storage means for data originating from another communication device belonging to the second network, the data to be transmitted to the first network And a communication means.   2. The communication device according to claim 1, wherein in the second network, each communication device communicates with another communication device that exists outside the range of the wireless communication through a route via a neighboring communication device. Communication device.   The communication apparatus according to claim 1, wherein the predetermined type of data includes a request for acquiring an identifier of the communication apparatus.   4. The communication apparatus according to claim 3, wherein the predetermined type of data is an ARP packet or a DHCP packet.   The route generation means, when the identifier of the destination communication device is held in the identifier storage means for a route search request originating from another communication device belonging to the second network, the route search request The communication apparatus according to claim 1, wherein a response to is performed instead of the destination communication apparatus.   2. The communication apparatus according to claim 1, wherein the path generation unit notifies an identifier of the communication apparatus held in the identifier storage unit to another communication apparatus belonging to the second network. A communication system comprising a first network, a second network, and a communication device that connects the first network and the second network,
The communication device includes an identifier storage unit that holds an identifier of another communication device belonging to the first network, and data having a transmission source of the other communication device belonging to the first network is data of a predetermined type. In some cases, identifier management means for holding the identifier of the transmission source communication apparatus in the identifier storage means, path generation means for generating a path to the communication apparatus in which the identifier is held in the identifier storage means, Data processing for transmitting the data to the first network when the identifier of the destination communication device is held in the identifier storage means for data originating from another communication device belonging to the second network And a communication system. A path control method in a communication device that includes an identifier storage unit that connects the first network and the second network and holds identifiers of other communication devices belonging to the first network,
An identifier management procedure for holding an identifier of the transmission source communication device in the identifier storage means when data originating from another communication device belonging to the first network is a predetermined type of data;
A route generation procedure for generating a route to the communication device in which the identifier is stored in the identifier storage means;
If the identifier of the destination communication device is held in the identifier storage means for data originating from another communication device belonging to the second network, the data to be transmitted to the first network A route control method comprising: a processing procedure. In a communication apparatus comprising an identifier storage unit that connects the first network and the second network and holds an identifier of another communication apparatus belonging to the first network.
An identifier management procedure for holding an identifier of the transmission source communication device in the identifier storage means when data originating from another communication device belonging to the first network is a predetermined type of data;
A route generation procedure for generating a route to the communication device in which the identifier is stored in the identifier storage means;
If the identifier of the destination communication device is held in the identifier storage means for data originating from another communication device belonging to the second network, the data to be transmitted to the first network A program for causing a computer to execute a processing procedure.

Images