JP2014175771A - Wireless LAN router - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a wireless LAN router, having a communication disabled WAN-side channel, to use an external wireless LAN router as a substitutive WAN-side channel, while maintaining communication between the communication disabled wireless LAN router and radio slave equipment in an infrastructure mode.SOLUTION: A wireless LAN router 1 monitors life and death of a PPPoE connection. The wireless LAN router 1 in a communicating state sets a flag in a beacon to notify the outside of being available as a substitutive access channel. The wireless LAN router 1 having the communication disabled WAN-side channel radio transmits a request message including PPPoE setting information to the available wireless LAN router 1, so that the request destination establishes a substitutive connection. The request destination resets an IP address to radio slave equipment 3 in which the request source is used as a wireless access point. By frame transfer processing using communication between wireless access points, the request destination and the request source mutually enable communication between the radio slave equipment 3, subordinate to the request source, and the Internet.

Description

  The present invention relates to a technique for automatically setting a detour route using radio when a WAN (Wide Area Network) side line is not connected, and in particular, interconnects its own WAN side line and a wireless LAN (Local Area Network). The present invention relates to a detour route using a wireless LAN router.

  A general home access line is connected to the network side by a single line. In this environment, when the line is disconnected or the network side is broken, the access line is disconnected, and Internet access is impossible.

  On the other hand, in recent years, wireless LAN routers have been widely used as broadband routers having a wireless function.

  Conventionally, a technique has been proposed in which an ad hoc network is configured by wireless stations such as wireless LAN routers and an alternative route is secured when a certain route fails (Patent Document 1).

JP 2010-11103 A (Abstract)

  However, general user equipment uses a wireless LAN router in an infrastructure mode in order to connect one line of an access network as a WAN side line of the wireless LAN router. In the infrastructure mode, it is not possible to apply the detour route construction by the ad hoc network as in Patent Document 1.

  Therefore, the problem to be solved by the present invention is to maintain communication between the wireless LAN router and the wireless slave unit in which the WAN side line is disconnected in the infrastructure mode, while the disconnected wireless LAN router is connected to the external wireless LAN. The router is made available as an alternative WAN side line.

In order to solve the above-described problems, the wireless LAN router according to the present invention includes life / death monitoring means for monitoring communication of its own WAN side line, so that it is possible to know the life / death status of its own WAN side line.
Furthermore, the wireless LAN router according to the present invention comprises alternative destination holding means for communicating by radio broadcast with an external wireless LAN router that is an alternative connection accepting destination and acquiring the wireless communication address of the external wireless LAN router. Therefore, between the wireless LAN routers according to the present invention, it is possible to know the external wireless LAN router that is the destination of the alternative connection request.
Further, the wireless LAN router according to the present invention wirelessly transmits a request message for requesting an alternative connection to the wireless communication address when the life and death monitoring means determines that the life and death monitoring means is disconnected. The wireless LAN router according to the present invention includes WAN side control means for performing alternative connection using its own WAN side line when the request message is received from outside when the monitoring means determines that the communication is established. Between each other, the wireless LAN router whose own WAN side line is disconnected transmits the request message including information necessary for the alternative connection to the external wireless LAN router, and the wireless LAN that is the request destination The router decodes the request message and establishes a connection with the opposite device on the circuit provider side that provides the WAN side line on behalf of the requesting wireless LAN router. Rukoto can.
Furthermore, the wireless LAN router according to the present invention uses the wireless LAN router that requested the alternative connection as a wireless LAN access point when the WAN-side control means performs the alternative connection based on the received request information. Since there is a LAN side control means for wirelessly transmitting a request for resetting the IP address to an external wireless slave device, between the wireless LAN routers according to the present invention, the requested LAN side The control means assigns an IP (Internet Protocol) address to the wireless slave device under the request source, avoids IP address conflict between the request destination and the requesting slave device, and performs routing related to Internet access of the wireless slave device under the request source. This can be done by the requested wireless LAN router.
Furthermore, a wireless LAN router according to the present invention includes: a wireless slave device under its control as a wireless LAN access point; a wireless LAN router that is a request destination determined by the WAN-side control means as the transmission destination of the request message; Wireless relay means for transferring the frame interposed between the requester and the requester wireless LAN router in the infrastructure mode while the requester wireless LAN router establishes the alternative connection established by the requester. Can be used on the side.
As described above, according to the wireless LAN router according to the present invention, while the communication between the wireless LAN router that has been disconnected from the WAN-side line and the wireless slave unit is maintained in the infrastructure mode, the disconnected wireless LAN router is externally connected. The wireless LAN router can be used as an alternative WAN side line.

  More specifically, when the alive monitoring means determines that the communication is established, the alternative destination holding means transmits a predetermined flag in a beacon to the outside by wireless broadcast and receives the flag from the outside In this case, the substitution destination holding unit stores the transmission source address of the flag as the wireless communication address, and the WAN side control unit acquires the wireless communication address stored in the substitution destination holding unit. It is preferable to do. By using a beacon transmission function according to the IEEE802.11 wireless LAN standard, the wireless communication address of an alternative wireless LAN router can be continuously and automatically notified to the entire wireless communication area. Since the beacon transmission function is indispensable for the wireless LAN router, if the alternative destination holding means using the beacon transmission function is adopted, it becomes easy to apply the present invention to the existing wireless LAN router, and the opposite device on the circuit provider side It is possible to avoid adding functions.

  In addition, when the life and death monitoring means determines that the connection is not established, the alternative destination holding means voluntarily inquires by wireless broadcast at a predetermined timing, and obtains a wireless communication address from the response of the external wireless LAN router to the inquiry. It is also possible to adopt the mode to do. Although this aspect is more complicated to apply to an existing wireless LAN router than the above-described use of a beacon, it can be acquired at an arbitrary timing.

  The WAN-side control means performs alternative connection by PPPoE (PPP over Ethernet) using a user ID (Identifier) and a password acquired from the request message, and the alive monitoring means connects the PPPoE to its own WAN-side line. It is also preferable to monitor the communication of the WAN side line by transmitting Ping. In an optical fiber communication access network for homes that is spreading widely, it is common to connect in accordance with PPPoE defined in RFC2526. If the wireless LAN router according to the present invention supports PPPoE connection, it is possible to expect a density at which there are alternative connection request destinations within its own wireless communication area.

  The request is a Dynamic Host Configuration Protocol (DHCP) FORCERENEW message, the LAN-side control means wirelessly transmits the message to the requesting wireless LAN router, and the wireless relay means externally sends the message When it is received, it is also preferable to transfer to all the subordinate slave units. The FORCERENEW message defined in the RFC related to RFC (RFC3203) is a message for forcibly requesting the DHCP client to reconfigure the network, and is to be transmitted by unicast. Therefore, when the FORCERENEW message is transferred from the requesting wireless LAN router to all subordinate wireless slave devices, all of the subordinate wireless slave devices request the requesting wireless LAN router to assign an IP address. As described above, the LAN side control means can be realized by using the requesting DHCP server and the requesting DHCP client. Generally, a wireless LAN router implements a DHCP server / client function, and a wireless slave device implements a DHCP client. Therefore, if a LAN side control means using DHCP is adopted, the present invention is applied to an existing wireless LAN router. Easy to do.

  When the alive monitoring means determines that communication is resumed, it is also preferable that the wireless relay means stop forwarding the frame and resume sending to its own WAN side line. The requesting wireless LAN router automatically functions as a router after the communication is resumed, so that it can be restored without bothering the user.

  As described above, the present invention maintains the communication between the wireless LAN router and the wireless slave in which the WAN side line is disconnected in the infrastructure mode, and the disconnected wireless LAN router replaces the external wireless LAN router. It can be made available as a WAN side line.

Sequence diagram until an alternative connection is established between wireless LAN routers according to the embodiment The conceptual diagram which shows the installation environment of the wireless LAN router which concerns on embodiment Functional block diagram of the main part in the wireless router mode and the wireless repeater mode of the wireless LAN router according to the embodiment Conceptual diagram of PPPoE database according to the embodiment The conceptual diagram which shows the format of the beacon which concerns on embodiment Conceptual diagram of an alternative access line database according to the embodiment 1 is a conceptual diagram illustrating an example of a frame format used in communication between wireless access points according to an embodiment 1 is a conceptual diagram illustrating an example of a frame format for performing wireless communication between a requesting wireless LAN router and a wireless slave device according to an embodiment; 1 is a conceptual diagram illustrating an example of a frame format when a wireless LAN router of a request source according to the embodiment performs transfer processing between a wireless slave device under the request and a wireless LAN router of a request destination Flowchart when the wireless LAN router according to the embodiment operates in the wireless router mode Flow chart when the wireless LAN router according to the embodiment converts the operation from the wireless router mode to the wireless repeater mode Flow chart showing branch processing from FIG. Schematic diagram showing an example of disaster recovery by a wireless LAN router according to an embodiment

  A wireless LAN router (hereinafter simply referred to as “this wireless LAN router”) as an embodiment of the present invention will be described below with reference to the accompanying drawings. As shown in FIGS. 2 and 3, the wireless LAN router 1 operates in a wireless router mode or a wireless repeater mode. In the figure, for convenience of explanation, the wireless LAN router 1 operating in the wireless router mode is indicated as “wireless router” and is denoted by reference numeral “1”, and the wireless LAN router operating in the wireless relay mode is indicated as “wireless repeater”. "And labeled with" 1 ". In the wireless router mode, an IP packet routing process is performed between the own WAN side line 2 and the wireless slave unit 3 under its control as a wireless access point. In addition, in the functional block diagram of FIG. 3, although the part required for the function as a wireless router is abbreviate | omitted, these are general things. In the wireless repeater mode, the above-described routing is not performed, and the frame is transferred between the wireless slave device 3 under its control as a wireless access point and another wireless access point.

  The WAN side line 2 is a single line belonging to the access network. The WAN side line 2 is connected to the WAN side of the wireless LAN router 1 via a line terminator (not shown) such as an ONU (Optical Network Unit) on the user equipment side according to a transmission medium such as an optical fiber. . The line termination device on the user equipment side may be mounted on the wireless LAN router 1.

  The WAN side line 2 is a line connected according to PPPoE.

  The wireless slave device 3 includes a DHCP client having the wireless LAN router 1 operating in the infrastructure mode as a wireless access point and the wireless LAN router 1 as a DHCP server. Examples of the wireless slave device 3 include a personal computer equipped with a wireless LAN card and a mobile terminal connected by Wi-Fi (registered trademark).

  As illustrated in FIG. 3, the wireless LAN router 1 includes a PPPoE control unit 11 that executes control related to PPPoE connection, a control frame processing unit 12 that generates a beacon, a PPPoE database unit 13 that stores information related to PPPoE connection, An alternative access line database unit 14 for storing information related to a request destination for an alternative connection to the WAN side line, a frame transmission unit 15 for sending a frame to the WAN side, a frame reception unit 16 for receiving a frame from the WAN side, and DHCP A DHCP control unit 17 that executes control related to the frame, and a frame processing unit 18 that performs protocol conversion between the DHCP control unit 17 and a wireless LAN standard frame.

  As shown in FIG. 4, the PPPoE database unit 13 stores a PPPoE tunnel ID, a user ID (UID), and a password in association with each other. The PPPoE control unit 11 shown in FIG. 3 acquires a user ID and a password from the PPPoE database unit 13, and establishes a PPPoE connection with the opposite device on the circuit provider side, for example, an SLT (Subscriber Line Terminal). The PPPoE database unit 13 is requested to store the tunnel ID as a PPPoE tunnel ID.

  The life and death monitoring means according to the present invention includes a PPPoE control unit 11, a frame transmission unit 15, and a frame reception unit 16. That is, the PPPoE control unit 11 generates a frame for transmitting the Ping specified in PPPoE to the opposite device on the circuit provider side, and passes the frame to the frame transmission unit 15, which is transmitted to the WAN side line. Send to 2. The frame receiving unit 16 passes the frame of the response message to the Ping received from the opposite device to the PPPoE control unit 11. The PPPoE control unit 11 determines communication when a response message to Ping can be received within a predetermined time, and determines that communication does not occur when the response message cannot be received within a predetermined time. In this alive monitoring means, by continuously carrying out at a predetermined timing during the operation of the wireless LAN router 1, not only the communication state / disconnection state of the WAN side line 2 is confirmed, but also re-communication due to restoration is confirmed. be able to. Causes of the disconnection state that can be monitored by Ping include disconnection of the lead-in line from the access point to the house, failure of the line terminating device on the user side, wiring system equipment, backbone system equipment, in-house system equipment, and the like. When the alive monitoring means determines that the WAN side line 2 is disconnected, the wireless LAN router 1 automatically switches from the wireless router mode to the wireless repeater mode. As long as the alive monitoring means determines that the WAN side line 2 is in communication, the wireless LAN router 1 operates in the wireless router mode. The PPPoE control unit 11 notifies the control frame processing unit 12 of this every time it determines that the communication is established.

  The alternative destination holding means according to the present invention includes a control frame processing unit 12, an alternative access line database unit 14, a frame transmission unit 15, and a frame reception unit 16. That is, when the control frame processing unit 12 has a notification of effective communication, as shown in FIG. 5, the control frame processing unit 12 generates a beacon in a frame format defined in IEEE 802.11, which is a wireless LAN standard. The beacon has a header designating radio broadcast, and is a frame in which a predetermined flag is set in an area of “Vendor specific IE”. The control frame processing unit 12 passes the generated beacon to the frame transmission unit 15. The frame transmission unit 15 transmits a beacon from an output port for wireless communication to the outside. The flag setting for the beacon may be set unconditionally as long as the PPPoE control unit 11 determines that the communication is established. Good. The beacon received from the outside by the wireless LAN router 1 is transferred from the frame receiving unit 16 to the control frame processing unit 12. When the control frame processing unit 12 reads that the flag is set in the beacon, the control frame processing unit 12 acquires the MAC (Media Access Control) address and SSID of the transmission source from the beacon, and stores these to the alternative access line database unit 14. Request. The SSID is an identifier of an access point in an IEEE 802.11 series wireless LAN, and may be an ESSID extended to a network identifier. As shown in FIG. 6, the alternative access line database unit 14 stores the MAC address, the SSID, and the received signal strength (RSSI) measured by the wireless LAN router 1 at the time of reception in association with each other. The stored MAC address of the transmission source can be used as the wireless communication address of the external wireless LAN router 1 that is the accepting destination of the alternative connection.

  When the flag is received from a plurality of external wireless LAN routers 1, by storing all these MAC addresses in the alternative access line database unit 14, many alternative connection request destination candidates can be held.

  The WAN-side control means according to the present invention includes a PPPoE control unit 11, a PPPoE database unit 13, a frame transmission unit 15, and a frame reception unit 16. That is, when the alive monitoring means determines that the WAN side line 2 is disconnected, the PPPoE control unit 11 acquires its own user ID and password from the PPPoE database unit 13. Further, the PPPoE control unit 11 acquires a wireless communication address including a MAC address from the alternative access line database unit 14 of the alternative destination holding unit. Here, if a MAC address having a high RSSI among the MAC addresses stored in the alternative access line database unit 14 is preferentially acquired, communication between the wireless LAN router 1 of the MAC address and the wireless access point itself is performed. It can be performed under as good a condition as possible. As shown in FIG. 7, the PPPoE control unit 11 uses PPPoE information (with the acquired user ID and the acquired user ID) as a request message for requesting an alternative connection in the payload area in the frame format defined in IEEE 802.11. And a frame addressed to the acquired MAC address (address for wireless communication). The PPPoE control unit 11 passes the frame provided with the request message to the frame transmission unit 15. The frame transmission unit 15 transmits the frame from the output port for wireless communication to the outside. Hereinafter, the requested wireless LAN router 1 determined as the transmission destination of the request message is referred to as “requested wireless LAN router 1”.

  On the other hand, when the alive monitoring means determines that the WAN side line 2 is in communication, when the frame with the request message is received from the outside, the frame receiving unit 16 performs PPPoE control on the frame. Pass to part 11. The PPPoE control unit 11 requests the PPPoE database unit 13 to store the user ID and password acquired from the request message in the frame. Further, the PPPoE control unit 11 performs alternative connection using its own WAN side line. This alternative connection is authenticated with the opposite device on the circuit provider side using the acquired user ID and password, and is established with the opposite device. The PPPoE control unit 11 requests the PPPoE database unit 13 to store the PPPoE tunnel ID determined by the establishment. Hereinafter, the wireless LAN router 1 that is the request source of the alternative connection, that is, the external wireless LAN router 1 that is the transmission source of the request message is referred to as “requested wireless LAN router 1”. In the present invention, the request message includes at least information necessary for the requested wireless LAN router 1 to establish a connection with the opposite apparatus, and other information such as communication quality setting information, expiration date, etc. May be included as appropriate.

  The PPPoE control unit 11 requests alternative connection as described above, or when requested, the MAC address of the wireless LAN router 1 of the request destination or the request source is sent to its own frame transmission unit 15, frame reception unit 16, DHCP control. Notify the required part such as part 17. The frame transmission unit 15 or the like stores the MAC address in a predetermined reference memory area. The request-destination wireless LAN router 1 can know the MAC address of the request-source wireless LAN router 1 from the source address of the request message. Hereinafter, the external wireless handset 3 that uses the requesting wireless LAN router 1 as a wireless access point is referred to as an “external wireless handset 3”.

  The LAN-side control means according to the present invention includes a DHCP control unit 17, a frame processing unit 18, a frame transmission unit 15, and a frame reception unit 16. That is, when the PPPoE control unit 11 performs an alternative connection, the DHCP control unit 17 transmits a request for resetting the IP address to the external wireless slave device 3 to the requesting wireless LAN router 1. Request to the frame processing unit 18. This request consists of a DHCP FORCERENEW message. The frame processing unit 18 assigns the request to the payload area of the frame format defined in IEEE 802.11, generates a frame having the transmission destination address as the MAC address of the requesting wireless LAN router 1, and generates this frame transmission unit. Pass to 15. The frame transmission unit 15 transmits this from the wireless communication output port to the outside. When the frame receiving unit 16 of the request-source wireless LAN router 1 receives the frame to which the request is given from the request-destination wireless LAN router 1, the frame receiving unit 16 passes this to the frame transmitting unit 15. Further, the frame transmission unit 15 transfers the frame to all subordinate wireless slave units 3 by wireless transmission. When each wireless slave device 3 reads the frame with its own DHCP client, each wireless slave device 3 wirelessly transmits a frame to which a response message requesting resetting of the IP address is added. The frame receiving unit 16 of the requesting wireless LAN router 1 receives the frame from the subordinate wireless slave unit 3, and the frame transmitting unit 15 transfers the frame to the requesting wireless LAN router 1. When receiving the frame, the frame receiving unit 16 of the requested wireless LAN router 1 passes the frame to the frame processing unit 18, and the response message reaches the DHCP control unit 17 from the frame processing unit 18. Receiving this, the DHCP control unit 17 receives the external wireless slave device 3 (that is, the external wireless device corresponding to the subordinate of the requesting wireless LAN router 1 as the transmission destination of the request) from the IEEE 802.11 header of the response message. The MAC address of the device 3) is individually grasped, and an IP address (local) is assigned to the external wireless slave device 3 of the request source. As a result, the resetting is performed so that the IP address does not conflict between the node under the request-destination wireless LAN router 1 and the external (subordinate-subordinate) wireless slave unit 3. Therefore, the requested wireless LAN router 1 can perform the routing process after the alternative connection without any trouble.

  The wireless relay means according to the present invention includes a frame transmission unit 15 and a frame reception unit 16. The frame transmitting unit 15 and the frame receiving unit 16 are connected between themselves and the requesting wireless LAN router 1, between themselves and the requesting wireless LAN router 1, or between the subordinate wireless slave device 3 and the requesting destination. In order to enable wireless communication between the wireless LAN router 1 and the external wireless handset 3 that uses the requesting wireless LAN router 1 as a wireless access point, the MAC in the IEEE802.11 header Setting of addresses 1 to 4 of the header is performed. For example, when transmitting a request message to the request-destination wireless LAN router 1, as shown in FIG. 7, the frame transmission unit 15 sets Address 1 of the MAC header to the relay section transmission destination address: the request-destination wireless LAN router 1. MAC address, Address 2 is the relay section transmission source address: own MAC address, Address 3 is the End-End transmission destination address: MAC address of the request-destination wireless LAN router 1, Address 4 is the End-End transmission source address: its own MAC address The frame is converted into a set frame, which is transmitted to the outside from the output port for wireless communication. For example, when the wireless slave unit 3 is communicating to the Internet under the requesting wireless LAN router 1 operating in the wireless repeater mode, the frame receiving unit 16 of the requesting wireless LAN router 1 is shown in FIG. As described above, Address 1 is the transmission destination address: the MAC address of the requesting wireless LAN router 1, Address 2 is the transmission source address: the MAC address of the wireless slave device 3, and Address 3 is the SSID assigned to the wireless LAN under the requesting wireless LAN 1. , A frame with Address4 set to blank is received. As shown in FIG. 9, the frame transmitter 15 of the request source wireless LAN router 1 sets Address 1 to Relay 1 as the relay section destination address: MAC address of the request destination wireless LAN router 1 and Address 2 as shown in FIG. Relay section transmission source address: own MAC address, Address 3 is the End-End transmission destination address: MAC address of the request-destination wireless LAN router 1, Address 4 is the End-End transmission source address: the MAC address of the subordinate wireless slave unit 3 The frame is converted into a set frame, which is transmitted to the outside from the output port for wireless communication. In the case of communication from the Internet side to the external wireless slave device 3 under the request source, the frame transmission unit 15 of the request-destination wireless LAN router 1 replaces the MAC address between Address 1 and Address 2 in FIG. 4, the frame transmission unit 15 of the requesting wireless LAN router 1 simply sends out the frame with the MAC address exchanged between Address 1 and Address 2 in FIG. 8. is there. Since wireless LAN routers that perform communication between wireless access points in accordance with the IEEE 802.11 wireless LAN standard have become widespread, as in this wireless relay means, if the addresses 1 to 4 of the MAC header of the IEEE 802.11 frame format are used, It becomes easy to apply the present invention to an existing wireless LAN router.

  When the alive monitoring means determines that the communication is resumed, the frame transmission unit 15 stops the frame transfer between the subordinate slave unit 3 and the requested wireless LAN router 1, and sends it to its own WAN side line 2. Resume sending.

  The PPPoE control unit 11, the control frame processing unit 12, the PPPoE database unit 13, the alternative access line database unit 14, the frame transmission unit 15, the frame reception unit 16, the DHCP control unit 17, and the frame processing unit 18 are connected to a wireless router. Hardware such as an arithmetic processing device, a storage device, and a network interface provided in the wireless LAN router by executing a computer program on one or a plurality of arithmetic processing devices provided in the wireless LAN router having both functions of the mode and the wireless repeater mode Configured on hardware resources.

  FIG. 10 shows a flow when this wireless LAN router 1 is a request destination. As shown in FIG. 10, the wireless LAN router 1 connected to the WAN side line 2 and operating in the wireless LAN mode starts transmission of a beacon (S1). Thereafter, when the wireless LAN router 1 wirelessly receives a request message including PPPoE information from the outside (S2), the wireless LAN router 1 performs alternative connection using the PPPoE information (S3). Next, the wireless LAN router 1 wirelessly transmits a request for resetting the IP address to the external wireless slave device 3 subordinate to the request source, and assigns the IP address (S4). Thereafter, the wireless LAN router 1 appropriately performs routing processing on the external wireless slave device 3 to which the IP address has been previously assigned and communication with the requesting wireless LAN router 1 or the external wireless slave device 3 (S5), The header conversion required for wireless communication with the requesting wireless LAN router 1 and the external wireless slave device 3 is repeated (S6).

  The flow when this wireless LAN router 1 is the request source is shown in FIGS. When receiving a beacon from the outside (S11), the wireless LAN router 1 updates the alternative access line database unit 14 (S12). After that, the wireless LAN router 1 repeats the determination of communication of its own WAN side line 2 by the life and death monitoring means, and continues to operate in the wireless router mode as long as it is determined to be connected (S13, S14). Then, the alternative access line database unit 14 is searched (S15). Here, when there is no registration of an alternative access line, the alternative connection requesting operation is terminated (S16). On the other hand, when the alternative access line is registered, the MAC address of the registration record having the largest RSSI value is acquired (S17). Thereafter, the wireless LAN router 1 changes the operation to the wireless repeater mode (S18), acquires its own user ID and the like from the PPPoE database unit 13, and wirelessly transmits the PPPoE information to the MAC address acquired in (S17). Transmit (S19). After that, when the wireless LAN router 1 receives a wireless slave unit 3 under its control or a frame having the MAC address acquired in (S17) as a transmission source through communication between wireless access points (S20), the IEEE802.11 header The process of converting the addresses 1 to 4 of the MAC header according to the processing contents such as frame transfer is repeated (S21). In addition, as shown in FIG. 12, the wireless LAN router 1 repeats the parallel processing branching from (S18) until it determines that the communication of the WAN side line 2 by the alive monitoring means is communication (S31 to S33). If the communication is determined, the operation is changed to the wireless router mode (S34), and the process returns to S13 described above.

  FIG. 1 shows a sequence until an alternative connection is established between the wireless LAN routers 1 and 1. The wireless LAN router 1 operating in the wireless router mode monitors the communication of its own WAN side line, and when it is determined to be in communication, sets a predetermined flag in a beacon and transmits it to the outside by wireless broadcast (S1). , S11). The other wireless LAN router 1 stores the MAC address of the transmission source acquired from the beacon as an alternative connection accepting destination (S12). The wireless LAN router 1 operating in the wireless router mode performs a routing process in Internet communication of the subordinate slave unit 3 (S41). When the wireless LAN router 1 that has received the beacon determines that the WAN-side line is disconnected (S14), the wireless LAN router 1 wirelessly transmits a request message including PPPoE information to the MAC address stored as an alternative connection accepting destination, The operation is changed to the repeater mode (S2). The wireless LAN router 1 that has received this makes an alternative connection using its own WAN side line (S3), and with respect to the external wireless slave unit 3 located under the wireless LAN router 1 that requested the alternative connection. The IP address is reset (S4, S19). Thereafter, when communication is performed between the external wireless slave unit 3 and the Internet, the requesting wireless LAN router 1 operating in the wireless repeater mode appropriately converts the header and requests to operate in the wireless router mode. A frame is transferred by communication between wireless access points with the previous wireless LAN router 1 (S20, S21), and the requested wireless LAN router 1 is the requested wireless LAN router 1 or the external wireless slave device 3. When it is required for wireless communication, the header is converted (S5, S6).

  As described above, the wireless LAN router 1 performs communication between the wireless LAN router 1 and the wireless slave unit 3 in which the WAN side line 2 is disconnected by performing a frame transfer process by communication between wireless access points. Thus, the disconnected wireless LAN router 1 can use the external wireless LAN router 1 as an alternative WAN side line.

  In addition, since this wireless LAN router 1 employs alternative destination holding means using a beacon transmission function in accordance with the IEEE 802.11 wireless LAN standard, it is easy to apply the present invention to an existing wireless LAN router. In addition, it is possible to avoid the addition of the function of the opposite device on the line carrier side.

  Further, since this wireless LAN router 1 supports PPPoE connection, it is possible to expect a density at which there are alternative connection request destinations within its own wireless communication area. For example, during a natural disaster such as an earthquake, as shown in FIG. 13, the PPPoE-connected wireless LAN router 1 that is widely used in ordinary homes is disconnected from the WAN-side line 2 because the lead-in line to the home is cut off. Such a wireless LAN router 1 can occur simultaneously and frequently in a certain wireless LAN area in a natural disaster. By installing a temporary wireless LAN router 1 (wireless tower in the figure), it can be expected that these disconnected wireless LAN routers 1 at the same time will be restored simultaneously.

  In addition, since this wireless LAN router 1 employs LAN-side control means using DHCP, it is easy to apply the present invention to an existing wireless LAN router.

  Further, when the wireless LAN router 1 is in a state where it is determined that communication is resumed, the frame transfer to the requested wireless LAN router 1 is stopped, and transmission to the WAN side line 2 is automatically resumed. Recovery can be performed without bothering the user. The technical scope of the present invention is not limited to the above-described embodiment, but includes all modifications within the scope of the technical idea based on the description of the scope of claims.

1 Wireless LAN router 2 WAN side line 3 Wireless slave unit 11 PPPoE control unit 12 Control frame processing unit 13 PPPoE database unit 14 Alternative access line database unit 15 Frame transmission unit 16 Frame reception unit 17 DHCP control unit 18 Frame processing unit

Claims (5)

In a wireless LAN router that interconnects its own WAN side line and wireless LAN,
Life and death monitoring means for monitoring communication of the own WAN side line,
An alternative destination holding means for communicating by radio broadcast with an external wireless LAN router that is an accepting destination of the alternative connection and acquiring the wireless communication address of the external wireless LAN router;
When the life and death monitoring means is determined to be disconnected, a request message for requesting an alternative connection is wirelessly transmitted to the wireless communication address, and the life and death monitoring means is determined to be in communication When receiving the request message from the outside, WAN side control means for performing alternative connection using its own WAN side line;
When the WAN-side control means performs the alternative connection, the IP address is reset by itself for an external wireless slave device that uses the wireless LAN router that has requested the alternative connection as a wireless LAN access point. LAN side control means for wirelessly transmitting the request of
Wireless relay means for transferring a frame between a wireless slave device under its control as a wireless LAN access point and a wireless LAN router of a request destination determined as a transmission destination of the request message by the WAN side control means When,
A wireless LAN router comprising: When the alive monitoring means determines that the communication is established, the alternative destination holding means transmits a predetermined flag in a beacon to the outside by wireless broadcast,
When the flag is received from the outside, the alternative destination holding unit stores the transmission source address of the flag as the wireless communication address,
The wireless LAN router according to claim 1, wherein the WAN-side control unit acquires the wireless communication address stored in the alternative destination holding unit. The WAN-side control means performs an alternative connection by PPPoE using the user ID and password acquired from the request message,
The wireless LAN router according to claim 1 or 2, wherein the alive monitoring means monitors the communication of the WAN side line by transmitting a PPPoE Ping to the WAN side line. The request consists of a DHCP FORCERENE message,
The LAN side control means wirelessly transmits the request to the requesting wireless LAN router,
The wireless LAN router according to any one of claims 1 to 3, wherein when the wireless relay unit receives the request from the outside, the wireless relay unit transfers the request to all of the subordinate wireless slave devices.   5. The device according to claim 1, wherein when the life and death monitoring unit determines that communication is resumed, the wireless relay unit stops forwarding the frame and resumes transmission to the WAN side line. 6. Wireless LAN router.

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