JP4903909B2 - Communications system - Google Patents

Abstract

A connection adapter is interposed between high-level equipment and a communication module. The connection adapter and a router perform a circuit control and an address conversion processing so that the high-level equipment and a management computer set for the network connection service giving a fixed IP address can use the network connection service giving a dynamic IP address.

Description

  The present invention relates to a communication system used in the field of telemetering such as collection of sales information of vending machines and the field of telematics such as distribution of traffic information to a moving body.

  In recent years, telemetering and telematics for collecting and distributing information via a wireless packet communication network have become widespread. Telemetering was originally a general term for a mechanism for reading out the measurement value of a measuring instrument using a communication line. However, in recent years, the term is generally used not only for reading data but also for monitoring the operation of devices and for remote control. Representative examples of telemetering include a vending machine sales management system, a gas / water usage management system, and an unmanned parking management system. For the sales management system of the vending machine, refer to Patent Document 1. Telematics means providing information services in real time by combining a communication system with a mobile body such as an automobile. A typical example of telematics is an in-vehicle information system that provides traffic information and navigation information in real time to a terminal installed in a car.

  In such a field, a communication device for connecting to a wireless packet communication network and a host device using the communication device are required at a remote place. The host device corresponds to a data terminal equipment (DTE). The communication device corresponds to a data communication device (DCE: Data Circuit-terminating Equipment). For example, in a sales management system of a vending machine, a control device that performs sales control and temperature control in a warehouse corresponds to a host device.

  The wireless packet communication network is constructed using a network connection service provided by a communication carrier (carrier) for connecting a LAN and a wireless communication terminal. In this network connection service, a network router is installed in the LAN of the user of the service, and a wireless communication terminal can be connected to the LAN via a wireless packet communication network constructed by the service. The wireless communication terminal is connected to the LAN via the wireless packet communication network only when necessary using a protocol such as PPP (Point-to-Point Protocol). Here, the address space of the wireless packet communication network is predetermined by the carrier, and a fixed IP address included in the address space is assigned to the IP address on the wireless packet communication network side (WAN side) of the network router. In addition, as the IP address of the wireless communication terminal, a fixed IP address included in the address space is allocated, or one IP address included in the address space is dynamically assigned when connected to the wireless packet communication network. Is done.

JP 2003-51056 A

  The wireless packet communication network has various standards and service forms depending on the carrier. For this reason, the standards and operations of communication devices vary depending on the carrier. For example, depending on the network connection service provided by the carrier, the IP address assignment method, connection method, authentication method, and the like given to the connection terminal vary. Therefore, when designing a host device, a carrier and a communication device to be used are selected in advance and designed to perform an operation corresponding to the communication device.

  By the way, in recent years, after such a system has been constructed, there has been a demand to change carriers and services. The reason is, for example, the case where the radio wave condition is unstable or inappropriate in the carrier at the place where the host device is installed. In particular, there is a desire to change from a network connection service that assigns a fixed IP address to a connection terminal to a network connection service that dynamically assigns an IP address.

  However, in the network connection service that dynamically assigns an IP address, since the IP address of the connection terminal is indefinite, there is a problem that communication from the LAN side device cannot be started to the connection terminal. In addition, if the carrier or service is to be changed, it is necessary to change the communication device accordingly, and therefore, it is necessary to change or remodel the host device. Due to the nature of this type of system, the higher-level devices are distributed in remote locations. Therefore, if a large number of higher-level devices are already installed in the market, the work involved in changing or modifying the higher-level devices. Will be enormous. Further, it is conceivable that not only the carrier etc. are changed, but the same problem may occur with the change of the model of the communication device even in the same carrier. This problem can also occur in future carrier changes and model changes. Therefore, careful service selection, carrier selection, and model selection are necessary for system construction. Furthermore, when constructing a system using a plurality of carriers, services, and communication devices, it is necessary to prepare a host device corresponding to each carrier or communication device. For this reason, there is a problem that the cost for system construction is high.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a communication system that can use various network connection services.

In order to achieve the above object, in the present application, a LAN and a wireless communication terminal are connected via a first wireless packet communication network, and an IP address in the first address space is dynamically assigned to the wireless communication terminal. In a communication system using a network connection service to be granted, a wireless communication terminal includes a communication device corresponding to a data communication device (DCE: Data Circuit-terminating Equipment) connected to a first wireless packet communication network, and a second wireless communication terminal. A host device corresponding to a data terminal device (DTE) that performs communication using a communication device for a packet communication network, and a connection device that relays communication by intervening between the communication device and the host device. wherein said connecting device detects the connection process from the host device for the second radio packet communication network, the higher the connection process to the first wireless packet communication network comprising an authentication process And a connection control means for completing the connection process by responding to the second wireless packet communication network as a proxy for the connection process performed by the host device. Propose.

  According to the present invention, the host device in the LAN is connected to the first wireless packet communication network without modifying or changing the host device or the LAN set for the second wireless packet communication network. Can communicate with.

  The host device corresponds to a data terminal equipment (DTE). The communication device corresponds to a data communication device (DCE: Data Circuit-terminating Equipment). “Dynamically assigning an IP address” means that the communication network pays out an IP address to the wireless communication terminal when the wireless communication terminal connects to the wireless packet communication network. Here, as for the IP address payout, one of IP addresses included in a predetermined range may be paid out indefinitely, or an IP address corresponding to the wireless communication terminal may be paid out fixedly. Which case occurs depends on the form of service in the wireless packet communication network.

  As an example of a preferred aspect of the present invention, when the connection control means of the connection device receives a message using the messaging service provided by the first wireless packet communication network, the connection device connects to the upper device from the LAN side terminal. It is notified that there is a request, and the host device starts connection processing for the second wireless packet communication network upon receiving the notification.

  According to the present invention, even if the first wireless packet communication network is a network that dynamically assigns an IP address to a wireless communication terminal, it is possible to start communication from the LAN side.

  As described above, according to the present invention, a host device is connected to the first wireless packet communication network without modifying or changing the host device or LAN set for the second wireless packet communication network. Communication with a terminal in the LAN.

Configuration diagram of a communication system according to the first embodiment Network diagram assumed by host device Network diagram of system according to first embodiment Connection device configuration diagram Functional block diagram of the main controller of the connection device The figure explaining an example of the setting information in a connection apparatus Functional block diagram of network router The figure explaining an example of a high-order apparatus information table The figure explaining an example of an address conversion table The figure explaining the sequence at the time of using the network connection service assumed and starting communication from a high-order apparatus. The figure explaining the sequence at the time of using the network connection service assumed and starting communication from the management computer The figure explaining the sequence in the case of starting communication from a high-order apparatus in 1st Embodiment. The figure explaining the sequence in the case of starting communication from a high-order apparatus in 1st Embodiment. Diagram explaining address conversion processing The figure explaining the sequence in the case of starting communication from the management computer in the first embodiment The figure explaining the sequence in the case of starting communication from the management computer in the first embodiment Diagram explaining address conversion processing The figure explaining an example of the address conversion table in the case of impersonating a high-order apparatus Network diagram when disguising a host device The figure explaining the address translation processing when disguising the host device Network diagram of communication system according to second embodiment The figure explaining an example of a high-order apparatus information table Diagram explaining address conversion processing Configuration diagram of communication system according to third embodiment The figure explaining an example of an address management table The figure explaining the sequence in the case of starting communication from a high-order apparatus in 3rd Embodiment. Diagram explaining address conversion processing The figure explaining the sequence in the case of starting communication from the management computer in 3rd Embodiment The figure explaining the sequence in the case of starting communication from the management computer in 3rd Embodiment Diagram explaining address conversion processing

(First embodiment)
A communication system according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a telemetering system using a communication system according to the present invention.

  As shown in FIG. 1, the present system is intended to provide a network environment in which a host device 10 such as a control device of a vending machine is connected to a corporate LAN 50 via a wireless packet communication network 40. . Specifically, the host device 10 set for a network connection service that gives a fixed IP address or a terminal in the corporate LAN 50 (in the example of FIG. 1, the management computer 51 of the vending machine, etc.) The main object of the present invention is to make it possible to use a network connection service in which the wireless packet communication network 40 assigns a dynamic IP address to a connection terminal without performing the above. In order to solve this object, it is possible to start communication from a terminal in the corporate LAN 50 to the higher-level device 10 and to specify the higher-level device 10 in communication from the higher-level device 10. It is aimed. Hereinafter, the communication system will be described in detail.

  The host device 10 corresponds to a data terminal equipment (DTE). The host device 10 is designed to support a specific carrier and a network connection service provided by the carrier. Specifically, it is premised on the use of a network connection service that gives a fixed IP address to a connection terminal, and a communication module corresponding to the service is connected, and a connection protocol / authentication protocol corresponding to the service is used. Designed to accommodate.

  A network connection service assumed by the higher-level device 10 will be described. In this network connection service, a telephone number is assigned to a communication module in advance by a carrier. A wireless packet communication network provided with this network connection service is provided with a relay device that performs line control, packet relay, and the like. The relay device is assigned a telephone number corresponding to the corporate LAN that is the connection destination network. When a terminal connected to the communication module makes a call to a telephone number of a relay device in the wireless packet communication network, the terminal is connected to a predetermined network such as a corporate LAN. Connection to the relay device is permitted only from a communication module to which a telephone number is assigned in advance.

  FIG. 2 shows an example of a network diagram when the network connection service assumed by the host device 10 is used. As shown in FIG. 2, the host device 10 connects to the wireless packet communication networks 45 and 46 constructed by the network connection service using the communication modules 25 and 26. In this embodiment, it is assumed that the wireless packet communication network 45 and the communication module 25 conform to the PDC standard, and the wireless packet communication network 46 and the communication module 26 conform to the PHS standard. In this service, the IP address belonging to the 192.168.0.0/28 network is fixedly assigned to the WAN side interface of the network router 60 and the communication module 25. The host device 10 is connected to the LAN 50 by a terminal type network connection service. Therefore, the IP address assigned to the communication modules 25 and 26 is synonymous with the IP address assigned to the higher-level device 10. In addition, it is assumed that the IP address of each device is fixedly assigned in the corporate LAN 50 so as to belong to the 192.168.9.0/24 network. When the network router 60 receives a packet addressed to an IP address in 192.168.0.0/28 from the LAN 50, the network router 60 relays the packet to the wireless packet communication networks 45 and 46. On the other hand, upon receiving a packet addressed to an IP address within 192.168.9.0/24 from the wireless packet communication networks 45 and 46, the network router 60 relays the packet to the LAN 50. With such a configuration, the management computer 51 can start communication addressed to the fixed IP address of the host device 10, and the communication from the host device 10 also refers to the source IP address of the communication. The host device 10 can be specified.

  The present invention is based on the premise that the host device 10 and the management computer 51 are used as they are, and allows the network system to be constructed even in the wireless packet communication network 40 provided with the network connection service to which the dynamic IP is provided. .

  Next, a network connection service for assigning a dynamic IP address used in the present embodiment will be described. In this network connection service, a telephone number is assigned to the communication module 20 by a carrier in advance. As shown in FIG. 1, the wireless packet communication network 40 is provided with a relay device 41 that performs line control, packet relay, and the like. The terminal connected to the communication module 20 connects to the wireless packet communication network 40 by making a call by designating a predetermined special number. The terminal can connect to the corporate LAN 50 as a connection destination network by performing authentication processing using the PAP (Password Authentication Protocol) with the relay device 41. In the PAP authentication, the connection destination network is specified by including information for specifying the connection destination in the user name. In this network connection service, a predetermined range of IP address groups is assigned from the carrier to the wireless packet communication network 40, and each IP address included in the IP address group is assigned to each communication module 20 as an IPCP (Internet Protocol Control). Protocol). Note that the IP address assigned to the communication module 20 is indefinite, and the same IP address as that at the previous connection may be assigned or different.

  In this network connection service, it is assumed that a messaging service is provided to the user. This messaging service is not a network connection service using TCP / IP, but is implemented by a unique protocol using a wireless communication network. In this messaging service, a relatively short message can be transmitted by designating the telephone number of the communication module 20 to a predetermined messaging server 42 provided in the wireless packet communication network 40 or another network such as the Internet. Yes. HTTP is used for a message transmission request to the messaging server 42.

  Next, a network diagram of the system according to the present embodiment will be described with reference to FIG. FIG. 3 is a network diagram of this system. As shown in FIG. 3, in this system, a fixed IP address belonging to 192.168.9.0/24 is assigned to the corporate LAN 50 as in the network described with reference to FIG. 10 is assigned a fixed IP address belonging to 192.168.0.0/28. An address group of 172.16.0.0/28 is assigned to the wireless packet communication network 40, and a network router (hereinafter simply referred to as “router”) that is a boundary point between the wireless packet communication network 40 and the corporate LAN 50. The fixed IP address 172.16.0.14 is assigned to the 60 WAN side. In addition, when the communication module 20 is connected to the wireless packet communication network 40, an address within 172.16.0.0/28 is dynamically assigned (in the figure, expressed as 172.16.0.0.X for convenience). did). The connection device 1 is connected to the LAN 50 by a terminal type network connection service. Accordingly, the IP address of the connection device 1 is an IP address dynamically assigned to the communication module 20. In the present invention, in such a network environment, communication can be started from the management computer 51 in the corporate LAN 50 to the higher-level device 10, and communication has been started from the higher-level device 10 to the management computer 51. In this case, the host device 10 can be specified.

  Next, the connection device 1 will be described in detail. The connection device 1 includes a plurality of higher-level devices 10 corresponding to data terminal equipment (DTE: Data Terminal Equipment), and a plurality of types of communication equipment equipped with a data communication device (DCE: Data Circuit-terminating Equipment). It is a device for connecting the communication devices 20, 25, and 26. The connection device 1 according to the present embodiment corresponds to the CDMA standard communication module 20, the PDC standard communication module 25, and the PHS standard communication module 26. Each communication module 20, 25, 26 is a communication device connected to a wireless packet communication network 40, 45, 46 constructed by a corresponding carrier, and corresponds to a communication standard / communication protocol / service uniquely determined by each carrier. is doing. As described above, the host device 10 is designed to support a specific carrier and a service provided by the carrier. Specifically, the communication module corresponding to the service is connected, and the connection protocol / authentication protocol corresponding to the service is designed.

  The host device 10 according to the present embodiment can be directly connected to the PDC standard communication module 25 and the PHS standard communication module 26. Then, by using the communication modules 25 and 26, it is possible to connect to the corporate LAN 50 via the wireless packet communication networks 45 and 46. The connection device 1 according to the present embodiment can be connected to the corporate LAN 50 via the wireless packet communication network 40 using the CDMA standard communication module 20 without modifying or changing the host device 10. Hereinafter, the connection device 1 will be described in more detail.

  First, a configuration diagram of the connection device 1 according to the present embodiment will be described with reference to FIG. FIG. 4 shows a state in which the three communication modules 20, 25, and 26 are built in the connection device 1. In operation, at least only the communication module 20, 25 or 26 that is actually used may be incorporated.

  The connection apparatus 1 includes a main control board 110, a sub control board 200 for mounting the PDC standard communication module 25, and a sub control board 300 for mounting the CDMA standard communication module 20. , A PHS standard communication module 26 is provided. The sub control boards 200 and 300 and the communication module 26 are detachably attached to the main control board 110.

  In addition, the connection device 1 according to the present embodiment includes a plurality of types of connectors for connecting a host device so that the connection device 1 can be connected to a plurality of types of main control devices. Specifically, the main control board 110 includes a connector 111 used in the RS-232C standard, a connector 112 used in the RS-485 standard, and a connector 113 used in the CAN (Controller Area Network) standard.

  The main control board 110 includes a main control unit 120 implemented by an FPGA (Field Programmable Gate Array) which is a kind of PLD (Programmable Logic Device), an RS-232C standard interface circuit 131, and an RS-485 standard interface. A face circuit 132 and a CAN standard interface circuit 133 are provided. Each interface circuit 131, 132, 133 is interposed between the corresponding connector 111, 112, 113 and the main control unit 120. As a result, the main control unit 120 can communicate with the host device connected to the connectors 111, 112, 113 via the interface circuits 131, 132, 133.

  The main control board 110 includes a connector 141 for connecting to the sub control board 200, a connector 142 for connecting to the sub control board 300, and a connector 143 for connecting to the PHS standard communication module 26. I have. Each connector 141, 142, 143 is connected to the main control unit 120. As a result, the main control unit 120 can communicate with the PDC standard communication module 25 via the sub control board 200, and can communicate with the CDMA standard communication module 20 via the sub control board 300. Communication with the PHS standard communication module 26 is possible.

  Further, the main control board 110 is provided with an EPROM 151 that stores a control program of the main control unit 120 and a RAM 152 that is used as various work areas of the main control unit 120. Further, the main control board 110 is provided with a module selection switch 160 for selecting which communication module 20, 25, 26 is used. The main control unit 120 performs operations corresponding to the communication modules 20, 25, and 26 selected by the module selection switch 160. The configuration and operation of the main control unit 120 will be described later.

  The main control board 110 operates by supplying DC power from the outside and supplies DC power to the sub-control boards 200 and 300 and the PHS standard communication module 26 via the connectors 141, 142, and 143. . In addition, the main control unit 120 includes a power supply monitoring circuit 170 that monitors a supply abnormality of a DC power supply from the outside and a backup battery 171. When detecting a power supply abnormality from the outside, the power monitoring circuit 170 controls the power supply from the backup battery 171 to the main control board 110, the sub control boards 200 and 300, and the PHS standard communication module 26. When the power supply monitoring circuit 170 detects an abnormality in the power supply from the outside, the power supply monitoring circuit 170 notifies the main control unit 120 of the abnormality. Further, when the power monitoring circuit 170 detects a return of power supply from the outside after a power supply abnormality, the power monitoring circuit 170 notifies the main control unit 120 of the recovery.

  In addition, the main control board 110 is provided with a circuit initialization unit 180 for initializing and generating an internal circuit of the main control unit 120 mounted with FPGA. The circuit initialization unit 180 has a built-in program for initializing and generating the internal circuit of the main control unit 120, and the main control unit is provided in the FPGA according to an instruction from a terminal (not shown) connected to the outside. A circuit constituting 120 is formed.

  The sub-control board 200 is for connecting the main control board 110 and the PDC standard communication module 25, the connector 201 for connecting to the main control board 110, and the terminals 25 a of the PDC standard communication module 25. A connector 202 for connection and an interface circuit 210 for connecting the main control board 110 and the communication module 25 are provided. The interface circuit 210 performs conversion of the number of pins between the connector 202 and the connector 201, conversion of pin assignment, waveform shaping, and the like. Here, it is assumed that the communication module 25 according to the present embodiment requires a predetermined memory chip storing its own telephone number information and the like, and also requires a dedicated backup battery. In order to cope with this, the sub-control board 200 is configured such that the memory chip 220 and the backup battery 230 are connected to the communication module 25 via the connector 202. Further, as described above, the sub control board 200 operates with the DC power supplied from the main control board 110 and supplies DC power to the communication module 25 via the connector 202. The antenna connection terminal 25 b of the communication module 25 is connected to the antenna connection terminal 191 provided on the housing 100.

  The sub-control board 300 is for connecting the main control board 110 and the communication module 20 of the CDMA standard, the connector 301 for connecting to the main control board 110, and the terminal 20a of the communication module 20 of the CDMA standard. A connector 302 for connection and an interface circuit 310 for connecting the main control board 110 and the communication module 20 are provided. The interface circuit 310 performs conversion of the number of pins between the connector 302 and the connector 301, conversion of pin assignment, waveform shaping, and the like. Further, as described above, the sub control board 300 operates with the DC power supplied from the main control board 110 and supplies DC power to the communication module 20 via the connector 302. The antenna connection terminal 20 b of the communication module 20 is connected to the antenna connection terminal 192 attached to the housing 100.

  A terminal 26 a of the PHS standard communication module 26 is connected to the connector 143 of the main control board 110. The antenna connection terminal 26 b of the communication module 26 is connected to an antenna connection terminal 193 provided on the housing 100.

  Next, the configuration and operation of the main control unit 120 will be described with reference to FIG. FIG. 5 is a functional block diagram of the main control unit 120. Here, only those related to the gist of the present invention are described, and other configurations are omitted.

  As shown in FIG. 5, the main control unit 120 includes a line control unit 121 that performs line control such as establishment of a line connection, and a communication control unit 122 that controls data communication on the line established by the line control unit 121. And an interface 123 with the host device 10 and an interface 124 with the communication modules 20, 25, 26. The line control unit 121 performs line connection control using AT commands, and IP layer connection control using LCP (Link Control Protocol) and IPCP. The communication control unit 122 performs conversion processing of an IP address included in the header of the IP layer in data communication on the line established by the line control unit 121.

  The line control unit 121 and the communication control unit 122 switch processing according to the communication module 20, 25, 26 selected by the module selection switch 160. In the present embodiment, the host device 10 is designed so that the communication modules 25 and 26 can be directly connected and used. For this reason, when the communication module 25 or 26 is selected by the module selection switch 160, the line control unit 121 and the communication control unit 122 process data between the host device 10 and the communication module 25 or 26. Is transparent without any special treatment. On the other hand, when the communication module 20 is selected, the line control unit 121 and the communication control unit 122 convert the data between the upper level device 10 and the communication module 20 according to a predetermined rule. Dispose of it. Data necessary for the data processing is stored in the setting data storage unit 151a of the EPROM 151.

  The data stored in the setting data storage unit 151a will be described with reference to FIG. As shown in FIG. 6, the setting data storage unit 151 a is connected to the call command (including the telephone number) for connecting to the wireless packet communication network 40, the fixed IP address of the host device 10, and the wireless packet communication network 40. The authentication data necessary for the connection and the IP address of the connection destination router 60 are stored.

  Next, the router 60 installed at the boundary point between the wireless packet communication network 40 and the corporate LAN 50 will be described with reference to FIG. FIG. 7 is a configuration diagram of the router. As shown in FIG. 7, the router 60 includes a WAN-side interface 61, a LAN-side interface 62, a line control unit 63 that performs line control such as establishment of line connection, and a communication control unit that controls data communication. 64, a setting data storage unit 65 that stores data necessary for the operation of the communication control unit 64, and a log storage unit 66 that stores operation histories of the line control unit 63 and the communication control unit 64. The line control unit 63 performs IP layer connection control in cooperation with the connection device 1 and the messaging server 42. The communication control unit 64 converts the IP address included in the header of the IP layer on the line established by the line control unit 63. The setting data storage unit 65 stores at least data necessary for address conversion in the communication control unit 64.

  In the setting data storage unit 65, as shown in FIG. 8, a set of a fixed IP address (fixed terminal IP address) assigned to the host device 10 and a telephone number of the communication module 20 connected to the host device 10 is stored. An enumerated upper apparatus information table 65a is stored. Here, the fixed terminal IP address is assigned to the upper level apparatus 10 when using the network connection service to which the fixed IP address described above with reference to FIG. 2 is used. The setting data storage unit 65 also includes an address conversion table 65b that stores a set of IP addresses for which the communication control unit 64 performs address conversion for each communication. Specifically, as shown in FIG. 9, the address conversion table 65b includes a communication ID that is management information for identifying each communication, a fixed terminal IP address, and the connection device 1 of the host device 10 having the fixed terminal IP address. A set of IP addresses (dynamic terminal IP addresses) that are dynamically assigned to the IP address of the management computer 51 and the WAN side IP address of the router 60 are stored. ing. Each entry in the address conversion table 65b is generated every time communication between the management computer 51 and the higher-level device 10 occurs, and is deleted when the communication ends. In the present embodiment, the IP address of the management computer 51 is not a value that varies for each communication but a value that is fixedly set in advance.

  Next, a communication procedure in this system will be described with reference to the drawings. First, prior to the description of the communication system according to the present embodiment, a communication procedure in the case of using a network connection service that is a premise of the host device 10 and the management computer 51 will be described with reference to the drawings. As described above, since the host device 10 is compatible with the PDC standard communication module 25 and the first wireless packet communication network 45, the connection device 1 does not process data between the host device 10 and the communication module 25. No processing is performed. Also, the router 60 does not perform special processing. The same operation is performed when the host device 10 is connected to the corporate LAN 50 using the PHS standard communication module 26 and the wireless packet communication network 46.

  First, with reference to the sequence chart of FIG. 10, the case where communication is started from the upper level apparatus 10 to the management computer 51 will be described.

  Here, the following contents are assumed. That is, it is assumed that a telephone number “080AABB” is assigned to the communication module 25 from the carrier. An IP address of 192.168.0.0/28 is distributed from the carrier, and the higher-level device 10 connected to the wireless packet communication network 45 using the communication module 25 has an IP address of 192.168.0.1. Is assigned. The IP address of the communication partner management computer 51 is 192.168.9.10. The communication module 25 is connected to the relay device of the wireless packet communication network 45 by calling the telephone number “080 CCDD” with the “ATDT” command.

  As shown in FIG. 10, when the host device 10 issues an “ATDT080 CCDD” command to the connection device 1 (step S1), the line control unit 121 of the connection device 1 transfers the command to the communication module 25 as it is. (Step S2). An example of the trigger of the call is when an IP packet having a destination address: 192.168.0.10 is generated. In response to the AT command, the communication module 25 calls the relay apparatus in the wireless packet communication network 45 (step S3). Here, the relay device confirms the telephone number of the communication module 25 as the caller, and rejects the connection from the terminal outside the contract (step S4). When the line control unit 121 of the connection device 1 receives the response “CONNECT” to the effect that the connection has been completed at the line level via the communication module 25 (step S5), the response is transferred to the host device 10 (step S6). .

  Next, the host device 10 starts processing to connect to the corporate LAN 50 via the wireless packet communication network 45 by PPP. Specifically, the connection at the IP level with the relay device of the wireless packet communication network 45 is established by LCP and IPCP (steps S7 and S8). Here, the line control unit 121 of the connection apparatus 1 allows the packets related to the LCP and IPCP to be transmitted in both directions. As described above, the upper level apparatus 10 and the in-house LAN 50 can communicate at the IP level, and hence data communication using the upper level protocol such as TCP / UDP is started (step S9). Note that the relay device of the wireless packet communication network 45 relays only IP packets whose destination or source IP address is included in 192.168.0.0/28 (step S10).

  Next, a case where communication is started from the management computer 51 to the host device 10 will be described with reference to the sequence chart of FIG.

  When the management computer 51 issues a connection request addressed to a fixed IP address previously assigned to the host apparatus 10 in order to communicate with the host apparatus 10 of the communication partner (step S11), the router 60 The packet is sent to the wireless packet communication network 40 according to the routing rule. Thereby, the relay device of the wireless packet communication network 45 refers to the destination IP address of the packet and connects to the communication module 25 of the telephone number corresponding to the IP address (step S12). The communication module 25 notifies the connection device 1 that an incoming call has been received (step S13). The connection device 1 relays the incoming notification to the higher-level device 10 (step S14). Next, when there is a response to the incoming call notification from the upper level device 10 (step S15), the connection device 1 starts a connection establishment process by PPP with the relay device. Specifically, the connection device 1 establishes connection at the IP level with the relay device of the wireless packet communication network 45 by LCP and IPCP (steps S16 and S17). Here, the line control unit 121 of the connection apparatus 1 allows the packets related to the LCP and IPCP to be transmitted in both directions. As described above, the upper level device 10 and the in-house LAN 50 can communicate at the IP level, and hence data communication using the upper level protocol such as TCP / UDP can be performed thereafter. Therefore, the router 60 relays the connection request in step S11 to the higher-level device 10 (step S18). Then, the router 60 relays the response (step S19) from the higher-level device 10 to the management computer 51 (step S20). As described above, since the upper level device 10 and the in-house LAN 50 can communicate at the IP level, data communication using an upper level protocol such as TCP / UDP is started thereafter (step S21). Note that the relay apparatus of the wireless packet communication network 45 relays only the IP packet whose destination or source IP address is included in 192.168.0.0/28 (step S22).

  Next, a case in which the CDMA standard communication module 20 and the wireless packet communication network 40 are used without modifying or changing the host device 10 or the management computer 51 will be described with reference to the drawings.

  First, with reference to FIG. 12 to FIG. 14, a case where communication is started from the upper level apparatus 10 to the management computer 51 will be described. 12 and 13 are sequence charts when communication is started from the host device to the management computer. FIG. 14 is a diagram for explaining the IP address conversion process described in the header of the IP packet transmitted from the host device.

  Here, the following contents are assumed. That is, it is assumed that a telephone number “080XXYY” is assigned to the communication module 20 from the carrier. An IP address of 172.16.0.0/28 is distributed from the carrier, and the host device 10 connected to the wireless packet communication network 40 using the communication module 20 has an IP address of 172.16.0.0. Assume that one of / 28 is dynamically allocated. Assume that the router 60 is assigned an address of 172.26.0.14. The IP address of the communication partner management computer 51 is 192.168.9.10. The communication module 20 connects to the relay device 41 of the wireless packet communication network 40 by calling an “ATD9999” command. The relay device 41 performs user authentication by PAP and specifies a connection destination (intra-company LAN 50 in this example).

  As shown in FIG. 12, when the host device 10 issues an “ATDT080 CCDD” command to the connection device 1 (step S31), the line control unit 121 of the connection device 1 converts the command into “ATD9999”. Transfer to the communication module 20 (step S32). An example of the trigger for the call is when an IP packet having a destination address: 192.168.9.10 as shown in FIG. 14 is generated. In response to the AT command, the communication module 20 calls the relay device 41 in the wireless packet communication network 40 (step S33). When the line control unit 121 of the connection apparatus 1 receives a response “CONNECT” indicating that the connection is completed at the line level via the communication module 20 (step S34), the line control unit 121 connects the connection apparatus 1 to the corporate LAN 50 by PPP. Start processing.

  First, the line control unit 121 of the connection device 1 starts an LCP negotiation with the relay device 41 of the wireless packet communication network 40 (step S35). Next, the line control unit 121 of the connection device 1 performs PAP authentication processing with the relay device 41 of the wireless packet communication network 40 (step S36). This PAP authentication process is not assumed in the host device 10 created for the wireless packet communication network 45, but is necessary when the wireless packet communication network 40 is used. Therefore, in the present embodiment, the connection device 1 performs authentication processing on behalf of the host device 10. When this authentication process is completed, the line control unit 121 of the connection device 1 starts IPCP negotiation between the connection device 1 and the relay device 41 of the wireless packet communication network 40 (step S37). As a result, the IPCP negotiation is completed, and the dynamic IP address: 172. 16.0. X is given. The assigned dynamic IP address is stored in storage means such as EPROM 151.

  When the PPP negotiation is completed, the line control unit 121 of the connection device 1 has a special value (for example, 0) indicating to the router 60 that the telephone number of the communication module 20 is a call from the host device 10. The communication ID is notified to the router 60 by a UDP packet (step S38). Then, the line control unit 63 of the router 60 that has received the notification from the connection device 1 registers an entry in the address conversion table 65b for the communication ID included in the notification. Specifically, the communication ID included in the notification, the fixed terminal IP address acquired from the higher-level device information table 65a, the source IP address (= dynamic terminal IP address) of the packet storing the notification, the management The predetermined IP address of the computer for use 51 and the WAN side IP address of the router 60 are registered in the address conversion table 65b. As a result, the address conversion table 65b has data necessary for address conversion in the communication.

  Next, the line control unit 63 of the router 60 sends a connection request “CONNECT” in the IP layer to the management computer 51 (step S39). At this time, the fixed IP address of the host device 10 is used as the source IP address of the IP packet. That is, the packet related to this connection request is a prefetch of the connection request issued by the higher-level device 10 in the subsequent steps S45 to S48. Note that the IP addresses of the host device 10 and the management computer 51 are acquired by referring to the address conversion table 65b.

  Next, when receiving the response “ACCEPT” to the connection request (Step S40), the line control unit 63 of the router 60 transmits a response including the communication ID to the connection device 1 as a response of Step S38 (Step S41). . Note that the destination IP address of the response received from the management computer 51 is the fixed IP address of the higher-level device 10. However, the line control unit 63 of the router 60 does not relay the packet to the wireless packet communication network 40 at this stage.

  The line control unit 121 of the connection device 1 that has received the response from the router 60 transmits a response “CONNECT” to the effect that the connection has been completed at the line level to the upper level device 10 (step S42). The host device 10 receives the response and starts LCP negotiation and IPCP negotiation (steps S43 and S44). Here, it should be noted that the line control unit 121 of the connection device 1 responds to the higher-level device 10. As a result, the host device 10 seems to be performing connection processing with the packet communication network 45 described above with reference to FIG.

  Through the above processing, IP level communication can be performed between the host device 10 and the connection device 1 and between the connection device 1 and the management computer 51. Therefore, the host device 10 sends a connection request “CONNECT” in the IP layer to the management computer 51 (step S45). This connection request corresponds to the first packet of data communication in step S9 of FIG. Therefore, the destination IP address is the IP address of the management computer 51, and the transmission source IP address is the fixed terminal IP address of the higher-level device 10. The line control unit 121 of the connection device 1 converts the destination IP address into the WAN-side IP address of the router 60 for this connection request, and the dynamic terminal IP address given from the wireless packet communication network 40 by the source IP address And sent to the router 60 (step S46). The line control unit 63 of the router 60 responds to the connection device 1 in response to the connection request (step S47). The line control unit 121 of the connection device 1 that has received the response converts the destination IP address into the fixed terminal IP address of the higher-level device 10 and converts the transmission source IP address into the IP address of the management computer 51. 10 (step S48).

  Through the above processing, the host device 10 determines that the connection to the management computer 51 has been completed, and starts data communication to the management computer 51 (step S49). Here, the communication control unit 64 of the router 60 and the communication control unit 122 of the connection device 1 perform address conversion of the header of the IP packet (steps S50 and S51). Specifically, as shown in FIG. 14, the fixed terminal IP address (192.168.0.1) and the dynamic terminal IP address (172. 16.0.X) are mutually converted, and the router 60 The WAN side IP address (172.16.0.14) and the management computer 51 IP address (192.168.9.10) are mutually converted. Through the above processing, communication with the management computer 51 starting from the host device 10 becomes possible.

  Next, a case where communication is started from the management computer 51 of the in-house LAN 50 to the upper level apparatus 10 will be described with reference to FIGS. 15 and 16 are sequence diagrams of communication started from the management computer, and FIG. 17 is a diagram for explaining the process of address conversion.

  The management computer 51 issues a connection request “CONNECT” packet destined for the fixed terminal IP address previously assigned to the host device 10 in order to communicate with the host device 10 of the communication partner (step S71). The line control unit 63 of the router 60 returns a response to the management computer 51 in response to the connection request on behalf of the host device 10 (step S72).

  Next, the line control unit 63 of the router 60 acquires the telephone number corresponding to the destination IP address of the connection request packet from the higher-level device information table 65a. The line control unit 63 generates a communication ID for uniquely identifying the communication, and registers the communication entry in the address conversion table 65b. Then, the line control unit 63 sends a message to the acquired telephone number, that is, using the messaging service to the connection device 1 connected to the upper level device 10 (step S73). Here, the message is transmitted by requesting the messaging server 42 to transmit the message by HTTP. The message to be transmitted includes the communication ID.

  The line control unit 121 of the connection device 1 that has received the message starts connection processing to the first in-house LAN 50 based on the setting data stored in the setting data storage unit 151a. Specifically, an “ATD9999” command is sent to the communication module 20 (step S74). In response to the AT command, the communication module 20 calls the relay device 41 in the wireless packet communication network 40 (step S75). When the line control unit 121 of the connection apparatus 1 receives a response “CONNECT” indicating that the connection is completed at the line level via the communication module 20 (step S76), the line control unit 121 connects the connection apparatus 1 to the corporate LAN 50 by PPP. Start processing.

  First, the line control unit 121 of the connection device 1 starts LCP negotiation with the relay device 41 of the wireless packet communication network 40 (step S77). Next, the line control unit 121 of the connection device 1 performs PAP authentication processing with the relay device 41 of the wireless packet communication network 40 (step S78). Next, the line control unit 121 of the connection device 1 starts IPCP negotiation between the connection device 1 and the relay device 41 of the wireless packet communication network 40 (step S79). As a result, the IPCP negotiation is completed, and the dynamic IP address: 172. 16.0. X is given. The assigned dynamic IP address is stored in storage means such as EPROM 151.

  When the PPP negotiation is completed, the line control unit 121 of the connection device 1 transmits the communication ID received from the router 60 to the router 60 using a UDP packet (step S80). The line control unit 63 of the router 60 transmits a response including the communication ID to the connection device 1 (step S81), and for the communication ID received from the connection device 1, the transmission source IP of the packet storing the communication ID The address (= dynamic terminal IP address) and the WAN-side IP address of the router 60 are registered in the address conversion table 65b. As a result, the address conversion table 65b has data necessary for address conversion in the communication.

  Next, the line control unit 63 of the router 60 relays the connection request packet of step S71 to the connection device 1 (step S82). At this time, the destination IP address of the connection request packet is converted into the dynamic terminal IP address of the connection device 1, and the transmission source IP address is converted into the WAN side IP address of the router 60. When receiving the connection request, the line control unit 121 of the connection device 1 notifies the higher-level device 10 that there is an incoming call (step S83). Upon receiving the incoming call notification, the host device 10 notifies the connection device 1 of a response to the incoming call notification (step S84) and starts LCP negotiation and IPCP negotiation (steps S85 and S86). Here, it should be noted that the line control unit 121 of the connection device 1 responds to the higher-level device 10. As a result, the host device 10 seems to be performing connection processing with the packet communication network 45 described above with reference to FIG.

  When this PPP negotiation is completed, the line control unit 121 of the connection device 1 transfers the connection request packet received from the router 60 in step S82 to the upper level device 10 (step S87). At this time, the destination IP address of the connection request packet is converted into the fixed terminal IP address of the higher-level device 10. The host device 10 that has received the connection request packet returns the response to the connection device 1 (step S88). The destination and source IP address of the response packet are values obtained by exchanging the destination IP address and source IP address of the connection request packet. The connection device 1 converts the source IP address into the dynamic terminal IP address of the connection device 1 and transmits it to the router 60 (step S89).

  Through the above processing, the host device 10 determines that the connection to the management computer 51 has been completed, and starts data communication to the management computer 51 (step S90). Here, the communication control unit 64 of the router 60 and the communication control unit 122 of the connection device 1 perform address conversion of the header of the IP packet (steps S91 and S92). Specifically, as shown in FIG. 17, the communication control unit 64 of the router 60 includes a fixed terminal IP address (192.168.0.1), a dynamic terminal IP address (172. 16.0.X), and Are mutually converted, and the WAN side IP address (172.16.0.14) of the router 60 and the IP address (192.168.9.10) of the management computer 51 are mutually converted. Further, the communication control unit 122 of the connection device 1 mutually converts the fixed terminal IP address (192.168.0.1) and the dynamic terminal IP address (172.16.0.0).

  As described above in detail, in the system according to the present embodiment, dynamic IP can be used without changing or remodeling the host device 10 and the management computer 51 that have used the network connection service to which a fixed IP is assigned. A network connection service that assigns addresses can be used. More specifically, communication from the management computer 51 to the host device 10 can be started even when a network connection service that assigns a dynamic IP address is used. In addition, since the source IP address of the packet received by the management computer 51 is a fixed IP address assigned in advance to the upper level device 10, the communication from the higher level device 10 to the management computer 51 is started. However, the management computer 51 can specify the communication partner.

  Further, in connection device 1 according to the present embodiment, data flowing between host device 10 and communication modules 20, 25, and 26 is converted, discarded, and transmitted so that each device can normally process the data. Various differences such as protocol / service / communication modules 20, 25, 26 between the packet communication networks 40, 45, 46 can be absorbed.

  Furthermore, in the system according to the present embodiment, the host device 10 connected to the management computer 51 can be disguised as another host device. Such a disguise method will be described with reference to FIGS.

  Here, as shown in FIG. 18, it is assumed that a fixed IP address of 192.168.0.1 is set in the first higher-level device 10 to be actually connected. Therefore, the source IP address of the IP packet sent from the first higher-level device 10 is 192.168.0.1. In such a case, as shown in FIG. 19, the fixed IP address assigned to the second higher-level device 11 different from the first higher-level device 10 and the first higher-level device 10 via the connection device. The telephone number of the connected communication module 20 is associated and stored in the upper device information table 65a. As described above, the router 60 acquires the fixed terminal IP address using the telephone number notified from the connection device 1 as a key, and converts the fixed terminal IP address and the dynamic terminal IP address to each other. Therefore, as shown in FIG. 20, the source IP address of the IP packet transmitted from the router 60 to the management computer 51 is not the address assigned to the first higher-level device 10 but the second higher-level device 11. The assigned address is stored. As a result, the management computer 51 can be disguised as communicating with the second higher-level device 11. If such disguise is possible, network address management can be managed collectively by the router 60, which is preferable in terms of operation.

(Second Embodiment)
Next, a network router according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 21 is a network diagram of a telemetering system using a network router according to the present embodiment.

  As shown in FIG. 21, in the corporate LAN 50, apart from the management computer 51 with the IP address 192.168.9.10 assumed by the host device 10 as a communication partner, the IP address 192.168.8.9. 11 second management computers 52 are connected. The object of the present embodiment is to enable communication using the second management computer 52 as a communication partner of the host device 10 without modifying or changing the host device 10. Since other objects, configurations, and effects are the same as those in the first embodiment, only differences will be described here.

  In order to realize such a configuration, as shown in FIG. 22, the IP address of the management computer 51 that is the actual communication partner of each host device 10 is stored in the host device information table 65a.

  The line control unit 63 of the router 60 receives the communication ID, telephone number, fixed IP address (fixed terminal IP address) of the host device 10 from the connection device 1 connected to the host device 10, and the IP address of the communication partner (example in FIG. 21). In 192.168.9.10) as a UDP packet, the IP address (192.168.9.11 in the example of FIG. 21) of the actual communication partner of the higher-level device 10 and a fixed number are received using the telephone number as a key. The terminal IP address is acquired from the upper device information table 65a. Then, the line control unit 63 of the router 60 includes the communication ID, the fixed terminal IP address acquired from the host device information table 65a, the source IP address of the packet storing the notification, the WAN side IP address of the router 60, the host device. The IP address of the management computer 52 acquired from the information table 65a is stored in the address conversion table 65b. As described above, the address conversion table 65b has data necessary for address conversion in the communication.

  Thereafter, the communication control unit 64 of the router 60 and the communication control unit 122 of the connection device 1 perform address conversion of the header of the IP packet related to the communication. Specifically, as shown in FIG. 23, the fixed terminal IP address and the dynamic terminal IP address are converted into each other, and the LAN side IP address of the router 60 and the IP address of the second management computer 52 are changed. Convert between each other. Through the above processing, communication with the second management computer 52 starting from the host device 10 becomes possible.

  As described above, according to the present embodiment, the actual connection destination of the host device 10 can be distributed to other connection destinations without changing or remodeling to the host device 10. It is also possible to freely change the IP address system on the corporate LAN 50 side. Other operations and effects are the same as those in the first embodiment. It should be noted that, in the present embodiment as well, it is possible to disguise the host device as in the first embodiment.

(Third embodiment)
A third embodiment of the present invention will be described with reference to the drawings. The main difference of the communication system according to the present embodiment from the first embodiment is the form of network connection service in the wireless packet communication network 40. Hereinafter, the difference between the connection service and the first embodiment will be described in detail.

  In this connection service, as in the first embodiment, an IP address is assigned to a connection terminal using a dynamic IP assignment technique. However, unlike the first embodiment, the IP address assigned to the connection terminal is predetermined. As shown in FIG. 24, an address management server 43 is installed in the wireless packet communication network 40. The address management server 43 manages a telephone number of a connection terminal and a list of IP addresses distributed to terminals having the telephone number. Specifically, as shown in FIG. 25, the address management server 43 includes an address correspondence table 43a describing correspondence between telephone numbers and IP addresses. The address management server 43 provides an interface to the user so that the address correspondence table 43a can be updated.

  In this connection service, the wireless packet communication network 40 acquires the telephone number of the connection terminal when the terminal is connected. Then, the IP address corresponding to the telephone number is acquired from the address correspondence table 43a, and the acquired IP address is distributed to the connection terminal. IPCP is used for this address distribution. That is, in this embodiment, although a dynamic IP assignment technique called IPCP is used, the distribution IP address is a predetermined one.

  In this connection service, the wireless packet communication network 40 receives an IP packet addressed to the IP address corresponding to the terminal from the corporate LAN 50 and the terminal is not connected to the wireless packet communication network 40. The messaging server 42 acquires a telephone number corresponding to the IP packet from the address management server 43 and transmits a message to the telephone number. This messaging service is not a network connection service using TCP / IP, but is implemented by a unique protocol using a wireless communication network. Accordingly, the terminal can recognize that there is a connection request from the corporate LAN 50.

  In the present embodiment, with the use of the network connection service as described above, the configurations and operations of the router 60 and the connection device 1 are different from those of the first embodiment. First, the router 60 will be described. The network address system in the present embodiment is the same as that shown in FIG.

  In the first embodiment, the router 60 includes the line control unit 63 and the communication control unit 64. The line control unit 63 performs operations such as notifying a connection request from the corporate LAN 50 side using a short message. However, in this embodiment, when a packet flows into the wireless packet communication network 40 from the corporate LAN 50, the wireless packet communication network 40 automatically transmits a message. Therefore, in the present embodiment, the line control unit 63 is not necessary. In the first embodiment, since the IP address of the connection terminal is indefinite, the communication control unit 64 of the router 60 performs an address conversion process. However, in this embodiment, since the IP address of the connection terminal is determined by the address management server 43, the communication control unit 64 does not need the address conversion process. Therefore, the communication control unit 64 of the router 60 only needs to have a general relay function for relaying between the corporate LAN 50 and the wireless packet communication network 40. In other words, the general router 60 in the assumed communication system described with reference to FIG. 2 can be used.

  On the other hand, the line control unit 121 of the connection device 1 performs line control such as establishment of line connection, as in the first embodiment. In addition, the communication control unit 122 controls data communication on the line established by the line control unit 121 as in the first embodiment. However, the operation of the line control unit 121 and the communication control unit 122 is different from that of the first embodiment, corresponding to the network connection service described above. The operation of the connection device 1 will be described later.

  Next, a communication procedure in this system will be described with reference to the drawings. First, with reference to FIG. 26 and FIG. 27, a case where communication is started from the upper level apparatus 10 to the management computer 51 will be described. FIG. 26 is a sequence chart when communication is started from the host device to the management computer, and FIG. 27 is a diagram for explaining the IP address conversion process described in the header of the IP packet transmitted from the host device.

  As shown in FIG. 26, when the host device 10 issues an “ATDT080 CCDD” command to the connection device 1 (step S101), the line control unit 121 of the connection device 1 converts the command into “ATD9999”. Transfer to the communication module 20 (step S102). An example of the trigger of this call is when an IP packet having a destination address: 192.168.9.10 as shown in FIG. 27 is generated. In response to the AT command, the communication module 20 calls the relay device 41 in the wireless packet communication network 40 (step S103). When the line control unit 121 of the connection apparatus 1 receives a response “CONNECT” indicating that the connection is completed at the line level via the communication module 20 (step S104), the line control unit 121 connects the connection apparatus 1 to the corporate LAN 50 by PPP. Start processing.

  First, the line control unit 121 of the connection device 1 starts an LCP negotiation with the relay device 41 of the wireless packet communication network 40 (step S105). Next, the line control unit 121 of the connection device 1 performs PAP authentication processing with the relay device 41 of the wireless packet communication network 40 (step S106). This PAP authentication process is not assumed in the host device 10 created for the wireless packet communication network 45, but is necessary when the wireless packet communication network 40 is used. Therefore, in the present embodiment, the connection device 1 performs authentication processing on behalf of the host device 10. When this authentication process is completed, the line control unit 121 of the connection device 1 starts IPCP negotiation between the connection device 1 and the relay device 41 of the wireless packet communication network 40 (step S107). As a result, the IPCP negotiation is completed, and the dynamic IP address: 172. 16.0. X is given. As described above, the IP address assigned here is largely different from that of the first embodiment in that it is predetermined for the communication module 20 that is a connection terminal. The assigned dynamic IP address is stored in storage means such as EPROM 151.

  When the PPP negotiation is completed, a response “CONNECT” indicating that the connection is completed at the line level is transmitted to the upper level apparatus 10 (step S108). The host device 10 receives the response and starts LCP negotiation and IPCP negotiation (steps S109 and S110). Here, it should be noted that the line control unit 121 of the connection device 1 responds to the higher-level device 10. As a result, the host device 10 seems to be performing connection processing with the packet communication network 45 described above with reference to FIG.

  Since the connection between the host device 10 and the corporate LAN 50 is completed by the above processing, the host device 10 starts data communication to the management computer 51 (step S111). Here, the communication control unit 122 of the connection device 1 performs address conversion of the header of the IP packet (step S112). Specifically, as shown in FIG. 27, the fixed terminal IP address (192.168.0.1) and the dynamic terminal IP address (172.16.0.0) are mutually converted. Through the above processing, communication with the management computer 51 starting from the host device 10 becomes possible.

  Next, a case where communication is started from the management computer 51 of the corporate LAN 50 to the host device 10 will be described with reference to FIGS. 28 and 29 are communication sequence diagrams starting from the management computer, and FIG. 30 is a diagram for explaining the address conversion process.

  Here, it is assumed that the IP address “172.16.0.1” is assigned in the address management server 43 to the communication module 20 connected to the higher-level device 10.

  The management computer 51 issues a connection request with the IP address “172.16.0.1” of the communication module 20 connected to the host apparatus 10 as the destination in order to communicate with the host apparatus 10 of the communication partner. Then (step S151), the router 60 relays the packet to the wireless packet communication network 40 according to a normal routing rule (step S152).

  The wireless packet communication network 40 refers to the destination IP address of the packet received from the router 60 and acquires the telephone number corresponding to the IP address from the address management server 43. Then, the telephone number is notified using a messaging service that a connection request has been received from the corporate LAN 50 (step S153). The wireless packet communication network 40 discards the packet related to the connection request received from the router 60.

  The line control unit 121 of the connection device 1 that has received the message starts connection processing to the first in-house LAN 50 based on the setting data stored in the setting data storage unit 151a. Specifically, an “ATD9999” command is sent to the communication module 20 (step S154). In response to the AT command, the communication module 20 calls the relay device 41 in the wireless packet communication network 40 (step S155). When the line control unit 121 of the connection apparatus 1 receives a response “CONNECT” indicating that the connection is completed at the line level via the communication module 20 (step S156), the line control unit 121 connects the connection apparatus 1 to the corporate LAN 50 by PPP. Start processing.

  First, the line control unit 121 of the connection device 1 starts LCP negotiation with the relay device 41 of the wireless packet communication network 40 (step S157). Next, the line control unit 121 of the connection device 1 performs PAP authentication processing with the relay device 41 of the wireless packet communication network 40 (step S158). Next, the line control unit 121 of the connection device 1 starts IPCP negotiation between the connection device 1 and the relay device 41 of the wireless packet communication network 40 (step S159). As a result, the IPCP negotiation is completed, and the dynamic IP address: 172. 16.0. X is given. As described above, the IP address assigned here is largely different from that of the first embodiment in that it is predetermined for the communication module 20 that is a connection terminal. The assigned dynamic IP address is stored in storage means such as EPROM 151.

  When the PPP negotiation is completed, the connection request packet arrives at the connection device 1 from the management computer 51 (step S160). As described above, the wireless packet communication network 40 discards the packet transmitted by the management computer 51 in step S151. For this reason, the management computer 51 cannot receive the response of the connection request packet, and retransmits the connection request packet due to timeout. In addition, since a certain amount of time is required for the processing of steps S153 to S159, some of the retransmitted packets time out further. Therefore, the connection request packet reaching the connection device 1 is the latest one of the packets retransmitted several times.

  When receiving the connection request packet from the management computer 51, the line control unit 121 of the connection device 1 notifies the higher level device 10 that an incoming call has been received (step S161). When receiving the incoming call notification, the host device 10 notifies the connection device 1 of a response to the incoming call notification (step S162), and starts LCP negotiation and IPCP negotiation (steps S163 and S164). Here, it should be noted that the line control unit 121 of the connection device 1 responds to the higher-level device 10. As a result, the host device 10 seems to be performing connection processing with the packet communication network 45 described above with reference to FIG.

  When this PPP negotiation is completed, the line control unit 121 of the connection device 1 transfers the connection request packet received from the management computer 51 in step S160 to the higher-level device 10 (step S165). The host device 10 that has received the connection request packet returns the response to the connection device 1 (step S166). The connection device 1 relays the response packet to the router 60 (step S167). The router 60 relays the response packet to the management computer 51 according to a normal routing rule (step S168).

  Through the above processing, the host device 10 determines that the connection to the management computer 51 has been completed, and starts data communication to the management computer 51 (step S169). Here, the communication control unit 122 of the connection device 1 performs address conversion of the header of the IP packet (step S170). Specifically, as shown in FIG. 30, the fixed terminal IP address (192.168.0.1) and the dynamic terminal IP address (172.16.0.1) are mutually converted.

  As described above in detail, in the communication system according to the present embodiment, since a general router 60 can be used, system construction can be performed more inexpensively and easily. Other effects are the same as those in the first embodiment.

  Although one embodiment of the present invention has been described in detail above, the present invention is not limited to this. For example, in the first and second embodiments, the router 60 refers to the source IP address of the packet in which the notification received from the connection device 1 is stored, so that the dynamic address given to the connection device 1 is obtained. Although the IP address has been acquired, this dynamic IP address may be included in the content of the notification.

  In the above embodiments, a telemetering system for managing vending machines has been described. However, the present invention can be implemented in other telemetering systems and telematics systems.

  Further, in each of the above embodiments, the communication module is exemplified by the PDC standard, the CDMA standard, and the PHS standard, but the present invention can be implemented even if it is of another standard. Similarly, other than the above-mentioned interface standards can be applied to the interface standard on the host device side.

  In each of the above embodiments, as a difference between the network connection service in the wireless packet communication networks 45 and 46 and the network connection service in the wireless packet communication network 40, an authentication method, an address system, an address assignment method (fixed IP address) Assignment or dynamic IP address assignment) is exemplified, but the present invention can be applied even when the difference is any one of these or a combination thereof. Furthermore, if necessary, other differences can be absorbed by the connecting device. For example, in the above embodiment, PAP authentication is performed in the wireless packet communication network 40. However, for example, when connecting to a communication network performing CHAP (Challenge Handshake Authentication Protocol) authentication, CHAP is installed in the connection device. That's fine.

  Further, in each of the above-described embodiments, the connection device 1 has the three communication modules 20, 25, and 26 built therein so that the wireless packet communication networks 40, 45, and 46 can be arbitrarily used. Only the communication modules 20, 25, and 26 may be built in or connected.

  DESCRIPTION OF SYMBOLS 1 ... Connection apparatus, 120 ... Main control part, 121 ... Line control part, 122 ... Communication control part, 10, 11 ... High-order apparatus, 20, 25, 26 ... Communication module, 40, 45, 45 ... Wireless packet communication network, 42 ... messaging server, 43 ... address management server, 50 ... corporate LAN, 51, 52 ... management computer, 60 ... network router, 63 ... line control unit, 64 ... communication control unit, 65 ... setting data storage unit, 65a ... host device information table, 65b ... address conversion table

Claims (2)

In a communication system using a network connection service for connecting a LAN and a wireless communication terminal via a first wireless packet communication network and dynamically assigning an IP address in a first address space to the wireless communication terminal ,
The wireless communication terminal performs communication using a communication device corresponding to a data communication device (DCE: Data Circuit-terminating Equipment) connected to the first wireless packet communication network and a communication device for the second wireless packet communication network. A host device corresponding to a data terminal equipment (DTE: Data Terminal Equipment) and a connection device that relays communications by interposing between the communication device and the host device;
When the connection device detects the connection processing for the second wireless packet communication network from the host device, the connection device performs the connection processing to the first wireless packet communication network including the authentication processing on behalf of the host device. A communication system comprising: connection control means for completing the connection process by responding to the second wireless packet communication network in response to the connection process performed by the network. When the connection control means of the connection device receives a message using the messaging service provided by the first wireless packet communication network, the connection control means performs the connection processing to the first wireless packet communication network on behalf of the host device, When the connection to the first wireless packet communication network is completed, the host device is notified that there is a connection request from the LAN side terminal, and the second wireless packet communication performed by the host device in response to the notification The communication system according to claim 1, wherein the connection process is completed by responding on behalf of the second wireless packet communication network for the connection process with the network.

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