JP2008054102A - Mobile machine and communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile machine capable of easily and quickly restarting a communication processing when moving to the outside of a communication area such as a radio LAN, and to provide a communication method. <P>SOLUTION: An IPsec (IP security) communication processing part 102 acquires communication information for performing a communication processing from the other communication party by using IPsec, stores the communication information for performing communication processing with the other communication party in a communication information storing part 105 and performs communication processing by using the communication information. When a within/outside range determining part 104 determines that mobile machine is located outside the range of a radio LAN, an included timer control part 106 clocks a predetermined time. When the within/outside range determining part 104 determines that the mobile machine returns within the range of the radio LAN before the included timer control part 106 clocks the predetermined time, the IPsec communication processing part 102 can perform communication processing by using the communication information stored in the communication information storing part 105. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a mobile device and a communication method that perform tunneling processing such as IPsec (IP security).

Mobile devices that perform tunneling processing using IPsec via a wireless LAN are known. For example, Patent Document 1 below describes that a mobile wireless terminal device establishes an IPsec tunnel with a network relay device via a wireless LAN access point to perform communication.
JP 2005-204086 A

  However, the conventional mobile device has the following problems. That is, when the mobile device moves from the inside of the wireless LAN area to the outside of the area, the wireless LAN communication cannot be performed and the communication is disconnected. Then, even if the mobile device again moves into the wireless LAN area and tries to continue communication, there is a problem that the mobile device cannot be continued and must be performed again from the communication connection process.

  Therefore, an object of the present invention is to provide a mobile device and a communication method capable of easily and quickly resuming communication processing even when moving outside a communication area such as a wireless LAN.

  In order to solve the above-described problem, a mobile device according to the present invention includes communication processing means for acquiring communication information for performing communication processing from a communication partner using a wireless LAN and performing communication processing using the communication information. Storage means for storing communication information for performing communication processing with the communication partner obtained by the communication processing means, and within-range / out-of-range determination means for determining whether the wireless LAN is out of range or within range When the range / out-of-range determining means determines that the wireless LAN is out of the range, the time-counting means for measuring a predetermined time and the time-out / out-of-range determination before measuring the predetermined time by the time-counting means. Control means for controlling the communication processing means to perform communication processing using the communication information stored in the storage means when the means determines that the wireless LAN has returned to the area within the wireless LAN. , And a.

  Further, the communication method of the present invention obtains communication information for performing communication processing from a communication partner using a wireless LAN and performing communication processing using the communication information, and the communication processing step. A storage step for storing communication information for performing communication processing with the communication partner, an in-range / out-of-range determination step for determining whether the wireless LAN is out of or within the range, and the in-range / out-of-range determination step When it is determined that the wireless LAN is out of the wireless LAN, the time measuring step of measuring a predetermined time and the time of the predetermined time being determined by the time measuring step are determined to have returned to the wireless LAN. A re-communication processing step for performing communication processing using the communication information stored in the storage step.

  According to the present invention, communication information for performing communication processing from a communication partner using a wireless LAN is acquired, the communication information is stored, and communication processing is performed using the communication information. Then, it is determined whether the wireless LAN is out of range or within range, and if it is determined that the wireless LAN is out of range, a predetermined time is counted, and before the predetermined time is counted, the wireless LAN is within the range. When it is determined that the communication has returned, communication processing can be performed using the stored communication information. As a result, communication can be easily continued without performing reconnection processing in the wireless LAN.

  In the mobile device of the present invention, whether the address information, which is one of the communication information stored in the storage means, matches the address information assigned when returning to the wireless LAN area. A communication continuation determining means for determining whether or not the communication processing means determines the communication information stored in the storage means when the communication continuation determining means determines that the address information does not match. It is preferable to erase and disconnect the connection state.

  According to the present invention, it is determined whether the address information that is one of the stored communication information and the address information assigned when returning to the area of the wireless LAN match, and the address information If it is determined that they do not match, the stored communication information can be erased and the connection state can be disconnected. This makes it possible to easily determine whether or not the wireless LAN has entered another wireless LAN, and when the wireless LAN has entered another wireless LAN, the connection state can be disconnected.

  The communication processing means in the mobile device of the present invention transmits dummy data using the communication information stored in the storage means to the communication partner and stores the response in the storage means when the response cannot be received. If the communication information is deleted, the connection state of the communication processing means is disconnected, and a response is received, it is preferable to perform communication processing using the communication information stored in the storage means .

  According to this invention, when the dummy data using the stored communication information is transmitted to the communication partner and the response cannot be received, the stored communication information is deleted, the connection state is disconnected, When the response is received, communication processing can be performed using the stored communication information. As a result, the communication connection maintenance state in the communication control device such as the PDG that is the reconnection destination can be easily known, and communication information is stored in the communication control device, and the communication connection cannot be maintained. The communication connection can be disconnected, and the communication process according to the maintenance state of the communication control device can be performed.

  Moreover, it is preferable that the mobile device of the present invention further includes an erasure unit that erases the communication information stored in the communication information holding unit when the time is counted by the timing unit.

  According to the present invention, when a predetermined time is counted, by deleting the stored communication information, it is possible to efficiently use a memory or the like without storing the communication information indefinitely.

  The present invention can easily continue communication without performing time-consuming reconnection processing even when the wireless LAN is out of service area.

  The present invention can be readily understood by considering the following detailed description with reference to the accompanying drawings shown for the embodiments. Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Where possible, the same parts are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a system configuration diagram of a communication system in which the mobile device 100 of the present embodiment can perform communication via a wireless LAN. As shown in FIG. 1, the mobile device 100 performs a tunneling process by IPsec with a PDG (Packet Data Gateway) 300 via a wireless LAN access point 200 to thereby establish a communication tunnel (hereinafter referred to as an IPsec tunnel). Can be established. Then, the mobile device 100 can perform connection processing with the communication partner using the SIP server 400 via the PDG 300 and the Internet 500.

  When establishing an IPsec tunnel with the PDG 300, the mobile device 100 can store communication information that is IPsec information for the establishment, and can perform communication processing using the stored communication information. Examples of the communication information include a security association and a security policy.

  The security association (SA) is a communication property that each of the mobile device that performs the IPsec communication and the PDG 300 that is the IPsec termination device must hold. Specifically, a destination IP address (IP address of a communication partner), an IPsec protocol to be used (for example, ESP: Encapsulating Security Payload), an encryption key, an authentication key (consisting of a hexadecimal random value), an SPI (Security Parameter Index) , Sequence number counter, sequence counter overflow flag, replay control window, encryption algorithm, authentication algorithm, SA valid period, path MTU (Maximum Transmission Unit), and the like.

  The security policy defines whether or not to apply IPsec to an IP packet when sending and receiving the IP packet, and what kind of IPsec function to apply. Specifically, the source IP address (terminal IP address), destination IP address (server IP address), protocol, destination port, processing to be applied (for example, ESP conversion), and the like.

  Next, the configuration of the mobile device 100 will be described. FIG. 2 is a block diagram of mobile device 100. As shown in FIG. 2, the mobile device 100 includes hardware such as a CPU, RAM, ROM, and a communication module. The wireless LAN control unit 101 and the IPsec communication processing unit 102 (communication processing unit and control unit). , Communication application 103, in-range / out-of-range determining unit 104 (in-range / out-of-range determining unit), communication information holding unit 105 (storage unit), holding timer control unit 106 (time counting unit, deleting unit), continuity determination processing unit 107 (continuation of communication) Determination means). Hereinafter, each component will be described.

  The wireless LAN control unit 101 is a part that communicates with the wireless LAN access point 200 by wireless communication.

  The IPsec communication processing unit 102 is a part that performs communication using IPsec via the wireless LAN control unit 101. Specifically, the IPsec communication processing unit 102 performs attribution processing for the access point 200 and DHCP (Dynamic Host Configuration Protocol) processing, and acquires an IP address assigned from the access point. Also, the IPsec communication processing unit 102 causes the communication information holding unit 105 to store communication information for performing IPsec communication acquired in the previous procedure. Then, the IPsec communication processing unit 102 performs a tunneling process with the PDG 300 using the communication information stored in the communication information holding unit 105, encapsulates data to be transmitted by IPsec, and receives the encapsulated reception. Process data.

  Further, the IPsec communication processing unit 102 operates to perform communication processing using the communication information stored in the communication information holding unit 105 when it goes out of the range of the wireless LAN and returns to the range. That is, when the IPsec communication processing unit 102 determines that the wireless LAN has gone out of the range of the wireless LAN and returned to the within range, the stored IP address matches the IP address assigned when the return is made again. Is instructed to the continuity determination processing unit 107. When the continuity determination processing unit 107 determines that the IP addresses match, the IPsec communication processing unit 102 that has received the message is generated using the communication information stored in the communication information holding unit 105. Send dummy data. When the IPsec communication processing unit 102 receives a response to the dummy data and notifies the continuity determination processing unit 107 to that effect, the continuity determination processing unit 107 can continue the IPsec communication in the reconnected PDG 300. It can be determined whether or not. In addition, when the IPsec communication processing unit 102 cannot receive a response to the dummy data, the IPsec communication processing unit 102 transmits the dummy data a predetermined number of times.

  The communication application 103 is a browser for browsing the Web, an e-mail application, or a file sharing application. Data generated by the communication application 103 is processed in the IPsec communication processing unit 102.

  The area / out-of-range determination unit 104 determines whether the wireless LAN control unit 101 is within the range of the access point 200 based on the reception status of the radio wave from the access point 200, that is, the electric field strength measured by the wireless LAN control unit 101. If the electric field strength is greater than or equal to a predetermined value, it is determined that the user is within the access point 200. If the electric field strength is less than the predetermined value, it is determined that the user is out of the service area. The in-range / out-of-range determination unit 104 outputs information indicating whether the mobile device 100 is within the range of the access point 200 or out of the range to the holding timer control unit 106.

  The communication information holding unit 105 is a part that stores communication information necessary for performing communication processing by IPsec in the IPsec communication processing unit 102. Further, the communication information holding unit 105 performs processing for releasing (erasing) the communication information stored in accordance with an instruction from the continuity determination processing unit 107.

  The holding timer control unit 106 includes a timer, and is a part that starts measuring a predetermined time based on information indicating whether the user is out of service area or in service area, which is input from the service area / out of service area determination unit 104. The holding timer control unit 106 instructs to release the communication information stored in the communication information holding unit 105 when a predetermined time is counted and timed out. In response to this instruction, the communication information holding unit 105 releases or deletes the communication information.

  The continuity determination processing unit 107 includes communication information (for example, an IP address) and communication information allocated by an access point in the area when the timer is reset due to the mobile device 100 entering the area in the holding timer control unit 106. By comparing the communication information (for example, IP address) stored in the holding unit 105 and determining whether or not they match, it is determined whether conduction is possible, that is, whether reconnection can be performed. It is a part to do.

  In addition, the continuity determination processing unit 107 receives a response to the dummy data transmitted by the IPsec communication processing unit 102 by the IPsec communication processing unit 102, and receives the fact from the IPsec communication processing unit 102, whereby the PDG 300 performs IPsec communication. It can be determined whether or not it is possible to continue. If the IPsec communication processing unit 102 cannot receive the response to the dummy data and determines that the IPsec communication cannot be continued, the continuity determination processing unit 107 stores the communication information stored in the communication information holding unit 105. Is released, the IPsec communication processing unit 102 is requested to establish a communication sequence for IPsec communication, and the communication process is performed again.

  Next, the operation of the mobile device 100 configured as described above will be described. FIG. 3 is a flowchart showing the operation of the mobile device 100 of the present embodiment.

  In accordance with a communication request from the communication application 103, a sequence for IPsec communication connection is executed by the IPsec communication processing unit 102 and the wireless LAN control unit 101 (S101), and communication information for executing communication by IPsec is communication information. It is stored in the holding unit 105 (S102). In parallel with this storage process, communication by IPsec is executed (S103).

  In the IP communication processing unit 102, it is determined whether the communication is in IPsec or the line is disconnected (S104). If it is determined that communication is in progress, the in-range / out-of-range determination unit 104 determines whether the wireless LAN is in or out of range based on the electric field strength (S105). Here, when it is determined that the user is out of service area by the service area / out of service determining unit 104, the timer of the holding timer control unit 106 is started (S106). Thereafter, until the timer of the holding timer control unit 106 times out (S108), the in-range / out-of-range determination unit 104 determines whether the mobile device 100 has entered or remains out of the range of the wireless LAN (S107). . Here, when the mobile device 100 does not enter the wireless LAN and times out in the holding timer control unit 106 (S108), the communication information stored in the communication information holding unit 105 according to an instruction from the holding timer control unit 106 Is released (erased) (S112).

  In S107, if the mobile device 100 enters the wireless LAN area (that is, the electric field strength is greater than or equal to a predetermined value) and is determined by the in-area / out-of-range determination unit 104, a timer is provided to the holding timer control unit 106. Is stopped, and the timer is reset (S109).

  When the wireless LAN is reconnected, the communication information (for example, IP address) allocated by the access point in the area and the communication information (for example, IP address) stored in the communication information holding unit 105 are transmitted by the continuity determination processing unit 107. By comparing and determining whether or not they match, it is determined whether conduction is possible, that is, whether or not reconnection can be performed (S110). Here, when the continuity determination processing unit 107 determines that the communication information does not match, it is determined that the communication information is in the range of another wireless LAN, and the communication stored in the communication information holding unit 105 by the continuity determination processing unit 107. Information is released (S108). Then, reconnection processing is performed.

  If it is determined that the communication information matches, dummy data (for example, UDP capsule) generated using the communication information stored in the communication information holding unit 105 is transmitted by the IPsec communication processing unit 102. It is transmitted to the PDG 300 via the access point 200. Then, by receiving the response of the transmitted dummy data, the continuity determination processing unit 107 determines whether or not the communication state using IPsec is continued (S111).

  If the continuity determination processing unit 107 determines that a dummy data response has been received, it is determined that reconnection has been normally completed, and IPsec communication is resumed (S103). If the continuity determination processing unit 107 determines that the dummy data response has not been received, it is determined that the reconnection is not completed, and the communication information holding unit 105 does not restart the communication using IPsec. Information is released (S108). In S111, the dummy data is transmitted a predetermined number of times until a response of the transmitted dummy data is received.

  Next, the operation of the PDG 300 that performs IPsec communication with the mobile device 100 will be described. FIG. 4 is a flowchart showing the operation of the PDG 300.

  In the PDG 300, an IPsec connection sequence is executed in response to an IPsec communication request from the mobile device 100 (S201). Then, the IPsec information is stored in the storage unit provided in the PDG 300 (S202). IPsec communication is performed between the PDG 300 and the mobile device 100 (S203), and when no data is received for a predetermined time (S204), the IPsec information held in the PDG 300 is released (S205). In addition, when data is received for a predetermined time in S204 and dummy data is received (S206), a response signal indicating that the dummy data has been received is transmitted (S207).

  In S206, IPsec dummy data is received using communication information stored in communication information holding unit 105 of mobile device 100, and the received dummy data is stored in PDG 300 for IPsec communication. If the communication information cannot be received, that is, if there is a difference in the contents of the communication information for IPsec between the mobile device 100 and the PDG 300, a dummy signal is transmitted without transmitting a response signal. Processed as if no data was received.

  A sequence process indicating a normal process or an error process in the mobile device 100 and the PDG 300 operating as described above will be described. FIG. 5 is a sequence diagram showing a sequence process until IPsec is established in the mobile device 100 and the PDG 300.

  Between the mobile device 100 and the access point 200, a belonging process in the wireless LAN is performed (S301), and a DHCP process is performed (S302). Then, an IP address acquisition process of the PDG 300 is performed with the DNS (Domain Name System) (S303).

  After performing such a pre-procedure, a processing procedure for performing IPsec communication with the PDG 300 in the mobile device 100 is executed (S304). Then, IPsec communication is established using the communication information for IPsec acquired in this processing procedure, and data communication by IPsec communication is performed (S305).

  FIG. 6 is a sequence diagram when IPsec communication can be normally resumed when the mobile device 100 moves out of the wireless LAN range and returns to the within range.

  During establishment of IPsec communication (S401), in the mobile device 100, the in-range / out-of-range determination unit 104 determines that the mobile device 100 has moved out of the range of the wireless LAN based on the electric field strength (S402). Then, according to this determination, the timer of the holding timer control unit 106 starts (S403). Thereafter, before the timer counts the predetermined time, if the field strength / out-of-range determination unit 104 determines that the electric field strength is equal to or greater than the predetermined value and the mobile device 100 has moved into the wireless LAN range (S404), IPsec The communication processing unit 102 performs wireless LAN attribution processing (S405) and DHCP processing (S406).

  Whether the communication information stored in the communication information holding unit 105 (for example, a locally allocated IP address) matches the reacquired communication information (for example, a locally allocated IP address). The continuity determination processing unit 107 determines that they match (S407). Thereafter, in the mobile device 100, a UDP capsule that is dummy data is generated, the generated UDP capsule is transmitted to the PDG 300, and a response is received (S408). Here, since the communication information matches and the UDP capsule which is dummy data can be received, the PDG 300 determines that the IPsec communication is continued, and the IPsec communication is continued as it is (S409).

  FIG. 7 is a sequence diagram when the IPsec communication cannot be normally resumed when the mobile device 100 moves out of the range of the wireless LAN and returns to the range.

  During establishment of IPsec communication (S501), in the mobile device 100, the in-range / out-of-range determination unit 104 determines that the mobile device 100 has moved out of the range of the wireless LAN based on the electric field strength (S502). Then, according to this determination, the timer of the holding timer control unit 106 starts (S503). Thereafter, before the timer counts the predetermined time, if the field strength / out-of-range determination unit 104 determines that the electric field strength is equal to or greater than the predetermined value and the mobile device 100 has moved into the wireless LAN range (S504), IPsec The communication processing unit 102 performs wireless LAN attribution processing (S505) and DHCP processing (S506).

  Then, it is determined whether or not the communication information (locally allocated IP address) stored in the communication information holding unit 105 matches the reacquired communication information (locally allocated IP address), Here, the continuity determination processing unit 107 determines that they match (S507). Thereafter, the mobile device 100 generates a UDP capsule which is dummy data, and transmits the generated UDP capsule to the PDG 300 (S508). Here, since the mobile device 100 does not receive a response of dummy data from the PDG 300, the UDP capsule is transmitted to the PDG 300 a predetermined number of times (S508). If there is a difference in other communication information other than the IP address in the PDG 300 and the PDG 300 cannot be normally received, the response is not transmitted.

  That is, when the mobile device 100 cannot receive a response to the dummy data from the PDG 300, the communication line disconnection process is performed in the IPsec communication processing unit 102, and the communication information release process is performed (S509). . In the IPsec communication processing unit 102, the IP address acquisition process of the PDG 300 is performed again on the DNS (S510). Then, the IPsec communication processing unit 102 performs a sequence process for IPsec communication with the PDG 300 (S511).

  FIG. 8 is a sequence diagram when the mobile device 100 moves out of the wireless LAN and moves into another access point.

  During establishment of IPsec communication (S601), in the mobile device 100, the in-range / out-of-range determination unit 104 determines that the mobile device 100 has moved out of the range of the wireless LAN based on the electric field strength (S602). Then, according to this determination, the timer of the holding timer control unit 106 starts (S603). Thereafter, before the timer counts the predetermined time, if the field strength / out-of-range determination unit 104 determines that the electric field strength is equal to or greater than the predetermined value and the mobile device 100 has moved into the wireless LAN range (S604), IPsec The communication processing unit 102 performs wireless LAN attribution processing (S605) and DHCP processing (S606).

  Then, it is determined whether or not the communication information stored in the communication information holding unit 105 (for example, a locally allocated IP address) matches the reacquired communication information (for example, a locally allocated IP address). In this case, the continuity determination processing unit 107 determines that they do not match (S607). Then, the communication line disconnection process is performed in the IPsec communication processing unit 102, and the communication information release process is performed (S608). Then, in the IPsec communication processing unit 102, the IP address acquisition process of the PDG 300 is performed again on the DNS (S609). Then, the IPsec communication processing unit 102 performs a sequence process for IPsec communication with the PDG 300 (S610).

  FIG. 9 is a sequence diagram when the mobile device 100 moves out of the wireless LAN area and times out without entering the wireless LAN area.

  During establishment of IPsec communication (S701), in the mobile device 100, the in-range / out-of-range determination unit 104 determines that the mobile device 100 has moved out of the range of the wireless LAN based on the electric field strength (S702). Then, the timer of the holding timer control unit 106 starts according to this determination (S703). Then, when the timer counts the predetermined time without entering the wireless LAN range (S704), the mobile station 100 performs the communication line disconnection process in the IPsec communication processing unit 102, and the communication information release process is performed. (S705). In this case, when the wireless LAN is again entered, it is necessary to start again from the communication information acquisition process, for example, from the sequence process shown in FIG.

  Next, operational effects of the mobile device 100 of the present embodiment will be described. In the mobile device 100 of the present embodiment, the IPsec communication processing unit 102 acquires communication information for performing communication processing by IPsec from the communication partner using the wireless LAN via the wireless LAN control unit 101, and performs communication processing with the communication partner. Communication information for performing communication is stored in the communication information holding unit 105, and communication processing is performed using the communication information. Then, the in-range / out-of-range determination unit 104 determines whether it is out of the range of the wireless LAN or within the range based on the electric field strength received by the wireless LAN control unit 101. When it is determined by the in-range / out-of-range determination unit 104 that the user is out of the range of the wireless LAN, the holding timer control unit 106 measures a predetermined time. Then, when it is determined by the in-range / out-of-range determination unit 104 that the holding timer control unit 106 has returned to the wireless LAN range before the predetermined time is measured, the communication information stored in the communication information holding unit 105 is used for IPsec. The communication processing unit 102 can perform communication processing. Thereby, IPsec communication can be easily continued without performing reconnection processing of IPsec communication in the wireless LAN.

  In this embodiment, communication information for performing IPsec communication is stored. However, the present invention is not limited to this, and when executing a communication method that uses some communication information when reconnecting, a predetermined information is used. The communication information may be stored for the time, and the stored communication information may be used when the communication process is performed again.

  Further, in this mobile device 100, the continuity determination processing unit 107 includes an IP address that is one of the communication information stored in the communication information holding unit 105, and the IP assigned when returning to the range of the wireless LAN. It is determined whether or not the address matches. If the continuity determination processing unit 107 determines that the IP addresses do not match, the IPsec communication processing unit 102 deletes the communication information stored in the communication information holding unit 105 and connects the IPsec communication. The state can be disconnected. As a result, it is possible to easily determine whether or not the wireless LAN has entered the range of another wireless LAN. When the wireless LAN has entered the range of another wireless LAN, the connection state of the IPsec communication can be disconnected. it can.

  Also, in this mobile device 100, when the IPsec communication processing unit 102 transmits dummy data using the communication information stored in the communication information holding unit 105 to the communication partner and cannot receive a response, the IPsec communication processing unit 102 holds the communication information. The communication information stored in the unit 105 is deleted, and the connection state is disconnected. Further, when the IPsec communication processing unit 102 receives the response, the communication processing can be performed using the communication information stored in the communication information holding unit 105. As a result, the mobile device 100 can easily know the maintenance state in the communication connection in the communication control device such as the PDG 300 that is the reconnection destination, and can establish communication connection by IPsec communication such as storing communication information in the PDG 300. When it is not in a state where it can be maintained, the communication connection can be disconnected, and communication processing according to the state of maintaining the IPsec communication of the PDG 300 can be performed.

  Also, in the mobile device 100, when the timer of the holding timer control unit 106 counts for a predetermined time, the holding timer control unit 106 deletes the communication information stored in the communication information holding unit 105 so that the communication information is kept forever. The memory such as the communication information holding unit 105 can be used efficiently without storing it.

1 is a system configuration diagram of a communication system in which a mobile device 100 of the present embodiment can communicate via a wireless LAN. 1 is a block diagram of a mobile device 100. FIG. It is a flowchart which shows operation | movement of the mobile device 100 of this embodiment. 5 is a flowchart showing the operation of the PDG 300. FIG. 10 is a sequence diagram showing a sequence process until IPsec is established in the mobile device 100 and the PDG 300. FIG. 10 is a sequence diagram when IPsec communication can be resumed normally when the mobile device 100 moves out of the range of the wireless LAN and returns to the range. FIG. 10 is a sequence diagram when IPsec communication cannot be resumed normally when the mobile device 100 moves out of the range of the wireless LAN and returns to the range. FIG. 10 is a sequence diagram when the mobile device 100 moves out of the wireless LAN and moves into another access point. FIG. 10 is a sequence diagram when the mobile device 100 moves out of the wireless LAN area and times out without entering the wireless LAN area.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Mobile device, 101 ... Wireless LAN control part, 102 ... IPsec communication processing part, 103 ... Communication application, 104 ... In-range / out-of-range determination part, 105 ... Communication information holding part, 106 ... Holding timer control part, 107 ... Continuity determination Processing unit 200 ... access point, 300 ... PDG, 400 ... SIP server, 500 ... Internet.

Claims (5)

Communication processing means for acquiring communication information for performing communication processing from a communication partner using a wireless LAN and performing communication processing using the communication information;
Storage means for storing communication information obtained by the communication processing means for performing communication processing with the communication partner;
Out-of-range / out-of-range determining means for determining whether the wireless LAN is out of range or within range;
When it is determined that the wireless LAN is out of the service area by the service area / out-of-service determining means, a time measuring means for measuring a predetermined time;
Communication is performed so that communication processing is performed using communication information stored in the storage means when the area / out-of-area determination means determines that the wireless LAN has returned to the area within the wireless LAN before the predetermined time is measured by the time measuring means. Control means for controlling the processing means;
A communication device comprising: Communication continuation judging means for judging whether or not the address information which is one of the communication information stored in the storage means and the address information assigned when returning to the area of the wireless LAN match. In addition,
The communication processing unit deletes the communication information stored in the storage unit and disconnects the connection state when the address information is determined not to match by the communication continuation determination unit. The communication device according to claim 1.   The communication processing means transmits dummy data using the communication information stored in the storage means to the communication partner, and when the response cannot be received, erases the communication information stored in the storage means. The communication processing means is controlled to disconnect the connection state of the communication processing means, and when a response is received, the communication processing is performed using the communication information stored in the storage means. The communication device according to claim 1 or 2.   4. The communication according to claim 1, further comprising: an erasing unit that erases the communication information stored in the communication information holding unit when the time counting unit measures a predetermined time. 5. apparatus. A communication processing step of acquiring communication information for performing communication processing from a communication partner using a wireless LAN and performing communication processing using the communication information;
A storage step for storing communication information obtained by the communication processing step for performing communication processing with the communication partner;
Within-range / out-of-range determination step for determining whether the wireless LAN is out of range or within range;
When it is determined that the wireless LAN is out of the service area by the service area / out of service area determination step, a time measuring step for measuring a predetermined time;
A re-communication processing step for performing communication processing using the communication information stored in the storing step when it is determined that the wireless LAN has returned to the area within the wireless LAN before measuring the predetermined time by the time measuring step;
A communication method comprising:

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