JP2009284206A - Connection device for communications equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connection device for communications equipment capable of utilizing a plurality of host devices at low cost. <P>SOLUTION: In the connection devices 1 and 1' for connecting the host devices 10 and 10' and a communication module 20, the respective connection devices 1 and 1' are connected via a private branch LAN 70, and the communication module 20 is connected only to one connection device 1. The connection devices 1 and 1' are provided with a route control part 120 for distributing IP packets received from the communication module 20 to the host devices 10 and 10' which are connected to themselves or to the other connection devices 1' and 1 which are connected via the private branch LAN 70. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a connection for connecting a communication device 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 mobile body, and a host device using the communication device. Relates to the device.

  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 usage management system for gas and water, a management system in an unmanned parking lot, and the like. 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 in a remote place and a host device using the communication device are arranged. 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. Each upper apparatus connects to a predetermined network via a communication device periodically or at any time, and connects to a predetermined management computer via the network. Then, the host device connected to the management computer transmits various management target data.
JP 2003-51056 A

  By the way, there are many cases where a plurality of vending machines are installed side by side or relatively close to each other in a vending machine sales management system or the like. In such a case, in the conventional system, a communication device is installed in each vending machine. For this reason, there is a problem that not only a large number of expensive communication devices are required, but also the control device (host device) of each vending machine performs communication separately, so that the communication cost increases.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a connection device for communication equipment that can use a plurality of host devices at low cost.

  In order to achieve the above object, the present invention provides a connection device that connects a communication device for connection to a wireless packet communication network and a host device that performs communication using TCP / IP via the communication device. A first interface for connection with a communication device, a second interface for connection with a host device, a third interface for connection with another connection device, and a first interface Route control means for distributing the IP packet received from the communication device via the interface to the upper device connected to the second interface or the other connection device connected via the communication interface It is characterized by.

  According to the present invention, the connection device according to the present invention is connected to each of a plurality of higher-level devices, the plurality of connection devices are connected via the third interface, and the communication device is connected to only one of the connection devices. By connecting the two, each host device can communicate using a common communication device. As a result, the number of communication devices and communication costs can be reduced.

  As an example of a preferred aspect of the present invention, the route control means rewrites the IP packet address information based on the IP packet address information and the port number of the TCP / UDP packet stored in the IP packet. To do. According to the present invention, even if there is only one IP address assigned to a communication device, a plurality of higher-level devices can be identified based on the port number, so that an appropriate IP packet reaches each higher-level device. Therefore, a plurality of higher-level devices can communicate using a common communication device.

  Further, as another example of the present invention, there is further provided a communication control means for controlling communication using a communication device by the host device. According to the present invention, expandability can be improved by implementing various functions in the communication control means. For example, even if the protocol / network service supported by the host device is different from the protocol / network service supported by the communication device, the communication control means performs conversion processing to absorb the difference. As a result, the host device can communicate using the communication device. As a result, various communication devices and network services can be employed without modifying the host device.

  As described above, according to the present invention, the connection device according to the present invention is connected to each of a plurality of higher-level devices, the plurality of connection devices are connected via the third interface, and any one connection is made. By connecting a communication device only to the device, each higher-level device can communicate using a common communication device. As a result, the number of communication devices and communication costs can be reduced.

  A connection device for a communication device according to an embodiment of the present invention will be described with reference to the drawings. First, a communication system using the connection device according to 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, this system provides a network environment in which a plurality of higher-level devices 10 and 10 ′ and an in-house LAN 50 are connected via a wireless packet communication network 40. Examples of the host devices 10 and 10 'are vending machine control devices. Connected to each higher level device 10, 10 'is a connection device 1, 1' according to the present invention. Each of the connection devices 1 and 1 ′ is connected to be communicable via the local area LAN 70. Furthermore, the communication module 20 is built in only one connection device 1 among the plurality of connection devices 1 and 1 ′. The connection device 1, 1 ′ according to the present invention communicates with a terminal (management computer 51 in the example of FIG. 1) in the corporate LAN 50, using a single communication module 20 common to the host devices 10, 10 ′. The first purpose is to make it possible.

  In this system, it is assumed that the host device 10 and the terminal in the corporate LAN 50 (the management computer 51 in the example of FIG. 1) are set for a network connection service that gives a fixed IP address. On the other hand, it is assumed that the wireless packet communication network 40 provides a network service that dynamically assigns an IP address. In the present invention, the connection devices 1 and 1 ′ are interposed between the host devices 10 and 10 ′ and the communication module 20, and the connection devices 1 and 1 ′ absorb differences in the network environment.

  The host devices 10 and 10 'correspond to data terminal equipment (DTE). The host devices 10 and 10 'are 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 assigns a fixed IP address to the 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.

  The network connection service that is assumed by the above-described upper devices 10 and 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.

  The present invention is based on the premise that such higher-level devices 10 and 10 ′ and the management computer 51 are used as they are, and a network system is constructed also in the wireless packet communication network 40 provided with a network connection service that provides a dynamic IP. The second purpose is to make it possible.

  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).

  Here, the IP address assigned to the connection terminal is predetermined. As shown in FIG. 1, 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, the address management server 43 is provided with an address correspondence table 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 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, 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 static 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.

  Next, the connection devices 1 and 1 'will be described in detail. The connection devices 1 and 1 ′ are devices that connect the higher-level devices 10 and 10 ′ corresponding to the data terminal device and the communication device 20 corresponding to the data communication device (DCE: Data Circuit-terminating Equipment). The connection devices 1 and 1 ′ according to the present embodiment correspond to the CDMA standard communication module 20. The communication module 20 is a communication device connected to the wireless packet communication network 40 constructed by each corresponding carrier, and corresponds to a communication standard / communication protocol / service uniquely determined by each carrier. As described above, the host devices 10 and 10 'are designed to correspond to 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. It is assumed that the higher-level devices 10 and 10 'according to the present embodiment can be directly connected to a PDC standard communication module and a PHS standard communication module. Then, it is assumed that the communication module can be used to connect to the corporate LAN 50 via each wireless packet communication network. The connection device 1, 1 ′ according to the present embodiment uses the communication module 20 of the CDMA standard via the wireless packet communication network 40 without modifying or changing the host device 10, 10 ′. Can be connected to. Hereinafter, the connection devices 1 and 1 ′ will be described in more detail.

  A configuration diagram of the connection device 1 according to the present embodiment will be described with reference to FIG. FIG. 2 is a functional block diagram of the connection device 1. Here, only those related to the gist of the present invention are described, and other configurations are omitted.

  Although the connection device 1 can physically incorporate the communication module 20, it is functionally a device that connects the communication module 20 and the host device 10 to each other as shown in FIG. Further, as shown in FIG. 1, the communication module 20 is not connected to the connection device 1 ′ connected to the host device 10 ′, that is, the connection device 1 operates even in a form in which the communication module 20 is not connected. To do. The connection devices 1 and 1 'operate as data communication devices for the host devices 10 and 10', respectively.

  As shown in FIG. 2, the connection devices 1 and 1 ′ are used to connect the interface 111 for connecting the communication module 20, the interface 112 for connecting to the host devices 10 and 10 ′, and the local LAN 70. Interface 113, a route control unit 120 that controls the destination route of the IP packet, and a communication control unit 130 that controls communication using the communication module 20 by the higher-level devices 10 and 10 ′ connected thereto. ing. Each of the interfaces 111 to 113 is mounted according to the connection destination standard. In the present embodiment, the host devices 10 and 10 'and the communication module 20 are connected according to the RS-232C standard, and therefore the interfaces 111 and 112 also conform to the standard. In the present embodiment, the local LAN 70 is constructed by Ethernet (registered trademark), and therefore the interface 113 is also compliant with the standard.

  The route control unit 120 will be described with reference to FIG. FIG. 3 is a functional block diagram of the path control unit. As shown in FIG. 3, the route controller 120 includes an address converter 121 that converts the address information of the input IP packet, and a routing processor 123 that controls the destination of the IP packet converted by the address converter 121. And. An IP packet is input to the address conversion unit 121 from the higher-level device 10, the communication module 20, and the local area LAN 70. The address conversion unit 121 is based on an address conversion table 122 set in advance in a predetermined storage means, and includes a destination IP address, a source IP address, a TCP / UDP destination port number and a source port number (hereinafter referred to as a higher-level protocol). These sets are referred to as address information). FIG. 4 shows an example of the address conversion table. As shown in FIG. 4, the address conversion table 122 stores a set of the address information before conversion and the address information after conversion. In the figure, the symbol “*” in the address information before conversion means that it matches any IP address or port number. Further, the symbol “*” in the converted address information means that no conversion is performed. When the address information of the input IP packet matches one of the address information sets before conversion in the address conversion table 122, the address conversion unit 121 converts the address information of the IP packet in the address conversion table 122. The address information is rewritten and sent to the routing processing unit 123. On the other hand, when the address information of the input IP packet does not match any of the address information sets before conversion in the address conversion table 122, the address conversion unit 121 sends the IP packet to the routing processing unit 123 as it is. .

  The routing processor 123 sends the IP packet received from the address translator 121 to an appropriate destination with reference to the routing table 124. FIG. 5 shows an example of the routing table 124. As shown in FIG. 5, the routing table 124 stores the address information of the IP packet and the destination of the IP packet. The transmission destination of the IP packet is any one of the host devices 10 and 10 ′, the communication module 20, and the local LAN 70. It should be noted that the connection device 1 ′ shown in FIG. 1 does not include the communication module 20, so that the communication module 20 does not exist as a transmission destination in the routing table 124 of the connection device 1 ′. The routing processing unit 123 acquires a destination that matches the address information of the IP packet received from the address conversion unit 121 from the routing table 124, and sends the IP packet to the destination. Note that the routing processing unit 123 sends an IP packet to the communication control unit 130 when the sending destination is for the higher-level devices 10 and 10 ′.

  Next, the operation of the route control unit 120 will be described with reference to the drawings. Here, the IP address previously assigned to the host device 10 is 192.168.0.1, the IP address on the local LAN 500 side of the connection device 1 is 192.168.200.10, and the communication module 20 is the wireless packet communication network 40. It is assumed that the IP address given when connecting to is 10.20.142.8 and the IP address of the management computer 51 that is the communication partner is 10.20.0.1. Further, it is assumed that the data shown in FIGS. 4 and 5 are stored in advance in the address conversion table 122 and the routing table 124.

  First, IP packet processing from the management computer 51 to the higher-level device 10 will be described with reference to FIG. As shown in FIG. 6, the address information of the transmission source of the packet input from the communication module 20 to the route control unit 120 is the IP address of the management computer 51 and an appropriate port number. On the other hand, the address information of the destination is an IP address assigned to the communication module 20 and a port number corresponding to the higher-level device 10. The address conversion unit 121 of the route control unit 120 performs address conversion processing with reference to the address conversion table 122 shown in FIG. Specifically, the first entry in the address conversion table 122 of FIG. 4 is applied. As a result of the address conversion process, the destination IP address of the IP packet becomes the IP address of the host device 10 as shown in FIG. The address translation unit 121 passes the IP packet to the routing processing unit 123. The routing processing unit 123 refers to the destination address information of the input IP packet and the routing table 124 shown in FIG. 5 and sends the IP packet to an appropriate destination. Specifically, the first entry of the routing table 124 is applied, and the IP packet is sent to the higher-level device 10 side (that is, the communication control unit 130).

  Next, processing of IP packets from the upper level device 10 to the management computer 51 will be described with reference to FIG. As shown in FIG. 7, the address information of the transmission source of the packet input from the higher level device 10 to the route control unit 120 is the IP address of the higher level device 10 and an appropriate port number. On the other hand, the destination address information is the IP address of the management computer 51 and the port number of a predetermined application. The address conversion unit 121 of the route control unit 120 performs address conversion processing with reference to the address conversion table 122 shown in FIG. Specifically, the second entry in the address conversion table 122 in FIG. 4 is applied. As a result of the address conversion process, the source IP address of the IP packet becomes the IP address of the communication module 20 as shown in FIG. The address translation unit 121 passes the IP packet to the routing processing unit 123. The routing processing unit 123 refers to the destination address information of the input IP packet and the routing table 124 shown in FIG. 5 and sends the IP packet to an appropriate destination. Specifically, the second entry in the routing table 124 is applied and an IP packet is sent to the communication module 20 side.

  Next, a case where the higher-level device 10 ′ communicates with the management computer 51 via the connection device 1 and the connection device 1 ′ will be described. Here, it is assumed that the IP address assigned in advance to the higher-level device 10 ′ is 192.168.200.1. The IP addresses of the host device 10, the connection device 1, and the communication module 20 are the same as described above. Further, it is assumed that nothing is stored in the address conversion table 122 of the connection device 1 ′, and the data shown in FIG. 8 is stored in advance in the routing table 124 ′.

  First, IP packet processing from the management computer 51 to the host apparatus 10 'will be described with reference to FIG. As shown in FIG. 9, the address information of the transmission source of the packet input from the communication module 20 to the path control unit 120 of the connection device 1 is the IP address of the management computer 51 and an appropriate port number. On the other hand, the address information of the destination is an IP address given to the communication module 20 and a port number corresponding to the higher-level device 10 '. The address conversion unit 121 of the route control unit 120 performs address conversion processing with reference to the address conversion table 122 shown in FIG. Specifically, the third entry in the address conversion table 122 of FIG. 4 is applied. As a result of the address conversion process, as shown in FIG. 9, the destination IP address of the IP packet is the IP address of the host device 10 '. The address translation unit 121 passes the IP packet to the routing processing unit 123. The routing processing unit 123 refers to the destination address information of the input IP packet and the routing table 124 shown in FIG. 5 and sends the IP packet to an appropriate destination. Specifically, the third entry in the routing table 124 is applied and an IP packet is sent to the local LAN 70 side. The IP packet is input to the route control unit 120 ′ of the connection device 1 ′ via the local area LAN 70. The address translation unit 121 ′ of the route control unit 120 ′ passes the IP packet as it is to the routing processing unit 123 ′ because the address translation table 122 is empty. The routing processing unit 123 'refers to the address information of the destination of the input IP packet and the routing table 124' shown in FIG. 8, and sends the IP packet to an appropriate destination. Specifically, the first entry in the routing table 124 ′ is applied, and an IP packet is transmitted to the higher-level device 10 ′ (that is, the communication control unit 130 ′).

  Next, IP packet processing from the upper level apparatus 10 ′ toward the management computer 51 will be described with reference to FIG. 10. As shown in FIG. 10, the address information of the transmission source of the packet input from the higher level apparatus 10 ′ to the route control unit 120 ′ of the connection apparatus 1 ′ is the IP address and an appropriate port number of the higher level apparatus 10 ′. . On the other hand, the destination address information is the IP address of the management computer 51 and the port number of a predetermined application. The address translation unit 121 ′ of the route control unit 120 ′ passes the IP packet as it is to the routing processing unit 123 ′ because the address translation table 122 is empty. The routing processing unit 123 'refers to the address information of the destination of the input IP packet and the routing table 124' shown in FIG. 8, and sends the IP packet to an appropriate destination. Specifically, the second entry of the routing table 124 ′ is applied and an IP packet is sent to the local LAN 70 side. The IP packet is input to the route control unit 120 of the connection device 1 via the local area LAN 70. The address conversion unit 121 of the route control unit 120 performs address conversion processing with reference to the address conversion table 122 shown in FIG. Specifically, the second entry in the address conversion table 122 in FIG. 4 is applied. As a result of the address conversion process, the source IP address of the IP packet becomes the IP address of the communication module 20 as shown in FIG. The address translation unit 121 passes the IP packet to the routing processing unit 123. The routing processing unit 123 refers to the destination address information of the input IP packet and the routing table 124 shown in FIG. 5 and sends the IP packet to an appropriate destination. Specifically, the second entry in the routing table 124 is applied and an IP packet is sent to the communication module 20 side.

  Next, the communication control unit 130 will be described with reference to the drawings. The communication control unit 130 performs line connection control using AT commands, IP layer connection control using LCP (Link Control Protocol) and IPCP, and conversion of an IP address included in an IP layer header in established data communication. Processing, proxy response processing of TCP packet, and the like are performed. These processes are performed when the protocol and service of the communication module 20 and the wireless communication packet communication network 40 are not premised on the higher-level devices 10 and 10 ′. And the difference in services. As a result, various devices can be employed as the wireless packet communication network 40 and the communication module 20 without any modification or correction to the host device 10 or the management computer 51 that is the communication partner.

  Next, line connection control in the communication control unit 130 will be described with reference to the drawings. Here, for simplicity of explanation, the line connection control in the host device 10 to which the connection device 1 incorporating the communication module 20 is connected will be described. First, with reference to FIG. 11, a case where communication is started from the host device 10 to the management computer 51 will be described. FIG. 11 is a sequence chart when communication is started from the host device to the management computer.

  As shown in FIG. 11, when the host device 10 issues an “ATDT080 CCDD” command to the connection device 1 (step S101), the communication control unit 130 of the connection device 1 converts the command into “ATD9999”. Transfer to the communication module 20 (step S102). An example of a trigger for this call is when an IP packet addressed to the management computer 51 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 communication control unit 130 of the connection device 1 receives a response “CONNECT” indicating that the connection is completed at the line level via the communication module 20 (step S104), the communication control unit 130 connects the connection device 1 to the corporate LAN 50 by PPP. Start processing.

  First, the communication control unit 130 of the connection device 1 starts LCP negotiation with the relay device 41 of the wireless packet communication network 40 (step S105). Next, the communication control unit 130 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 processing is not assumed in the host device 10, but is necessary when using the wireless packet communication network 40 according to the present embodiment. 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 communication control unit 130 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: 10.20.142.8 is assigned from the wireless packet communication network 40 to the communication control unit 130 of the connection device 1. The IP address assigned here is predetermined for the communication module 20 which is a connection terminal. The assigned dynamic IP address is stored in storage means such as an EPROM (not shown).

  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, what should be noted is that the communication control unit 130 of the connection device 1 responds to the higher-level device 10. With the above processing, the connection between the host device 10 and the corporate LAN 50 is completed.

  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. 12 and 13 are sequence diagrams of communication started from the management computer.

  Here, it is assumed that the IP address “10.20.142.8” is assigned in the address management server 43 to the communication module 20 connected to the upper level device 10.

  The management computer 51 issues a connection request with the IP address “10.20.142.8” of the communication module 20 connected to the host device 10 as the destination in order to communicate with the host device 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 communication control unit 130 of the connection device 1 that has received the message starts connection processing to the corporate LAN 50 based on the setting data stored in the setting data storage unit 151. 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 communication control unit 130 of the connection device 1 receives a response “CONNECT” indicating that the connection is completed at the line level via the communication module 20 (step S156), the communication control unit 130 connects the connection device 1 to the corporate LAN 50 by PPP. Start processing.

  First, the communication control unit 130 of the connection device 1 starts LCP negotiation with the relay device 41 of the wireless packet communication network 40 (step S157). Next, the communication control unit 130 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 communication control unit 130 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: 10.20.142.8 is assigned from the wireless packet communication network 40 to the communication control unit 130 of the connection device 1. As described above, the IP address assigned here is predetermined for the communication module 20 which is a connection terminal. The assigned dynamic IP address is stored in storage means such as an EPROM (not shown).

  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 the communication control unit 130 of the connection device 1 receives the connection request packet from the management computer 51, the communication control unit 130 notifies the higher-level device 10 that there is an incoming call (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, what should be noted is that the communication control unit 130 of the connection device 1 responds to the higher-level device 10.

  When this PPP negotiation is completed, the communication control unit 130 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). With the above processing, the host device 10 completes connection to the management computer 51.

  As described above in detail, according to the connection devices 1 and 1 ′ according to the present embodiment, the common communication module 20 can be shared by a plurality of higher-level devices 10 and 10 ′. Can be reduced. In addition, according to the connection devices 1 and 1 ′ according to the present embodiment, wireless packet communication that is not originally assumed by the host devices 10 and 10 ′ without modifying or changing the host devices 10 and 10 ′. Communication using the network 40 becomes possible.

  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 above embodiment, the telemetering system for monitoring the flow rate of the sewer has been described, but the present invention can be implemented in other telemetering systems and telematics systems.

  In the above-described embodiment, the communication module of the CDMA standard is exemplified, but the present invention can be implemented even if the communication module is of another standard. Similarly, other than the above-mentioned interface standards can be applied to the interface standard on the host device side.

Configuration diagram of communication system Functional block diagram of connection device Functional block diagram of the route controller The figure which shows an example of an address translation table Diagram showing an example of a routing table The figure explaining operation of a route control part The figure explaining operation of a route control part Diagram showing an example of a routing table The figure explaining operation of a route control part The figure explaining operation of a route control part Sequence diagram explaining operation of communication controller Sequence diagram explaining operation of communication controller Sequence diagram explaining operation of communication controller

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,1 '... Connection apparatus 10, 10' ... Host apparatus, 20 ... Communication module, 40 ... Wireless packet communication network, 50 ... Corporate LAN, 60 ... Local LAN, 111, 112, 113 ... Interface, 120 ... Route control unit, 121... Address conversion unit, 122... Address conversion table, 123... Routing processing unit, 124.

Claims (3)

A connection device that connects a communication device for connection with a wireless packet communication network and a host device that performs communication using TCP / IP via the communication device,
A first interface for connection with a communication device;
A second interface for connection with the host device;
A third interface for connection to another connection device;
Route control means for distributing an IP packet received from a communication device via the first interface to a host device connected to the second interface or to another connection device connected via the third interface; A connection device for communication equipment, comprising: The communication device connection according to claim 1, wherein the route control means rewrites the IP packet address information based on the IP packet address information and the port number of the TCP / UDP packet stored in the IP packet. apparatus. The communication device connection device according to claim 1, further comprising communication control means for controlling communication using the communication device by the host device.

Images