JP4380443B2 - COMMUNICATION DEVICE AND ITS CONTROL METHOD - Google Patents

Description

  The present invention relates to a communication apparatus that can move between networks and a control method thereof.

IPv6 address automatic configuration is standardized in Non-Patent Document 1 (RFC2462 IPv6 Stateless Address Autoconfiguration), and a communication terminal supporting IPv6 cooperates with a router in the same network, and its own IPv6 address and default router (default route). Can be set automatically. In addition, IPv6-compatible OSs such as Windows (registered trademark) XP, Free BSD, and Linux are also provided. However, when verifying the implementation on the actual OS, in Free BSD and Linux, there is no problem if the OS is started on the communication terminal while plugged in to the network in advance. If the network interface is plugged in after moving out and moving to another network, the network interface retains the network information (address, default router) before moving. For this reason, a situation occurs in which the address does not match that of the moved network, and communication is not possible on the moved network.
RFC 2462 IPv6 Stateless Address Autoconfiguration

  In the mobile environment, which is expected to be increasingly used in the future, it is expected that it will become common to work by moving between networks with the OS of the communication terminal activated. Under such circumstances, although IPv6 address automatic setting is standardized, it is not defined until actual implementation. Therefore, with implementation methods such as Free BSD and Linux, until the network setting is automatically updated, Internet applications will be left in error.

The present invention has been made in view of the above problems, a feature of the present invention, the network interface Link Stay up-, after having detected the Link down, setting and erasing the default router to OS (default route), It is an object of the present invention to provide a communication apparatus capable of explicitly controlling resetting and a control method therefor.

A communication apparatus according to one aspect of the present invention has the following configuration. That is,
A communication device having an application capable of communicating with a network,
In response to the address assignment in accordance with the connection with the network, and registration means for registering a default router to the destination of the packet in the network,
And deleting means for deleting a default router in response to disconnect from the network, the destination of the packet in the network that is registered by the registration means,
In response to the registration of the default router by the registration unit, the application is notified of the connection with the network, and the default router registered by the registration unit is deleted by the deletion unit. Notification means for notifying the application of disconnection from the network;
The application is characterized in that the communication with the network started based on reception of a notification of connection with the network is stopped in response to reception of a disconnection notification from the network .

A communication device control method according to an aspect of the present invention includes the following steps. That is,
A method for controlling a communication device having an application capable of communicating with a network,
A registration step of in response to the address assignment in accordance with the connection with the network, registering a default router to the destination of the packet in the network in a memory,
Depending on disconnected from the network, the deletion step for deleting a default router to the destination of the packet in the network registered in the memory,
In response to the registration of the default router in the registration step, the application is notified of connection with the network, and the default router registered in the registration step is deleted in the deletion step. A notification step of notifying the application of disconnection from the network,
The application is characterized in that the communication with the network started based on reception of a notification of connection with the network is stopped in response to reception of a disconnection notification from the network .

  According to the present invention, even if the connected network is switched to another network while the application is running, the network can be reset according to the new network, so that the user is conscious of movement between networks. For example, it is possible to perform communication by plug and play using an Internet application, for example.

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

  FIG. 1 is a diagram for explaining a network configuration according to an embodiment of the present invention.

  In the figure, reference numeral 100 denotes the Internet, which enables communication using a hierarchical mobile (IPv6) communication protocol. The terminal 101 is a portable terminal equipped with the plug and play function according to the present embodiment. The terminal 101 can communicate with other terminals connected to the Internet 100 using the IPv6 communication protocol. The routers 102 and 103 each perform packet transfer processing of the IPv6 communication protocol. Reference numerals 104 and 105 denote one LAN segment. When the router 102 transmits RA (Router Advertise) to the LAN segment 104, the terminal 101 connected to the LAN segment 104 can use the IPv6 automatic address setting function. The router 102 also functions as a gateway when the terminal of the LAN segment 104 communicates with the Internet 100. Similarly, the router 103 transmits an RA to the LAN segment 105, so that the terminal 101 connected to the LAN segment 105 can use the IPv6 automatic address setting function. The router 103 also functions as a gateway when the terminal of the LAN segment 105 communicates with the Internet 100.

  In this embodiment, the terminal 101 can be freely carried, and when the terminal 101 moves, the terminal 101 may be connected to the LAN segment 104 or may be connected to the LAN segment 105. In particular, a situation is assumed in which various applications running on the terminal 101 are moved between the LAN segments 104 and 105 in a few seconds without ending them. Such a situation can be considered, for example, when the user carries the terminal 101 and moves between two wireless LAN areas.

  FIG. 2 is a diagram for explaining network information of the routers 102 and 103, the LAN segments 104 and 105, and the terminal 101 according to the present embodiment. This information is stored in the RAM 903 shown in FIG.

  201 indicates the IPv6 global address of the terminal 101. Reference numeral 202 denotes an IPv6 network address of each of the LAN segments 104 and 105. Reference numeral 203 denotes a link local address of the network interface on the LAN segment side of the routers 102 and 103. Reference numeral 204 denotes a global address of the network interface on the LAN segment side of the routers 102 and 103.

  211 corresponds to a state in which the terminal 101 is connected to the LAN segment 104 and the global address of the terminal 101 is set by the automatic address setting function. In this case, the IPv6 global address of the terminal 101 is “2001: 340 :: 101”, the IPv6 network address of the LAN segment 104 is “2001: 340 :: / 64”, and the link local of the network interface on the LAN segment 104 side of the router 102 The address is “fe80 :: 102”, and the global address of the network interface on the LAN segment 104 side of the router 102 is “2001: 340 :: 102”.

  Reference numeral 212 denotes a state in which the terminal 101 is connected to the LAN segment 105 and the global address of the terminal 101 is set by the automatic address setting function. In this case, the IPv6 global address of the terminal 101 is “2002: 200 :: 101”, the IPv6 network address of the LAN segment 105 is “2002: 200 :: / 64”, and the link local of the network interface on the LAN segment 105 side of the router 103 The address is “fe80 :: 103”, and the global address of the network interface on the LAN segment 105 side of the router 103 is “2002: 200 :: 103”.

  FIG. 3 is a block diagram illustrating an example of a hardware configuration when the terminal 101 according to the present embodiment is connected to the LAN segment 104.

The terminal 101 includes a CPU 901, a ROM 902, a RAM 903, a hard disk (HD) 907, a disk controller (DC) 905 of a floppy (registered trademark) disk (FD) 908, and a network interface card (NIC) 906. The buses 904 are communicably connected to each other. A system bus 904 is connected to the LAN segment 104 via a network interface card (NIC) 906. CPU901 is software stored in the ROM902 or HD 907, or by executing the software supplied from FD908, it is to integrally control the components connected to the system bus 904. That is, the CPU 901 loads the processing program according to the processing sequence of FIGS. 7 to 9 described in this embodiment from the ROM 902, the HD 907, or the FD 908 to the RAM 903, and executes it. Control for realizing the operation according to the embodiment is performed. A RAM 903 functions as a main memory or a work area for the CPU 901. The DC 905 controls access to the HD 907 and the FD 908 that store a boot program, various applications, an edit file, a user file, a network management program, the processing program in the present embodiment, and the like. The NIC 906 performs mutual communication using the IPv6 communication protocol through the LAN segment 104 (or 105).

  FIG. 4 is a functional block diagram illustrating functional modules of terminal 101 according to the present embodiment.

  The NIC (network interface card) management 301 is a module that manages a network interface between the terminal 101 and the LAN segment. Specifically, the network address is set or deleted, and a communication packet addressed to the set address (self addressed) is transmitted or received. The ND management processing 302 is a module that performs processing related to IPv6 ND (Neighbor Discovery). This ND includes the issuance processing of RA and RS (Router Solicitation: message requesting RA) described above. The routing table 303 is a routing table in the terminal 101, which will be described later with reference to FIG. The default router list 304 is a database for registering RA transmission sources as candidates for default gateways (default routers), as will be described later with reference to FIG. As described above, the modules (305) indicated by 301 to 304 are often provided as functions in the kernel of a general OS.

  The NIC monitoring module 306 monitors each module of the NIC management 301, the ND management processing 302, the routing table 303, and the default router list 304, or requests a processing to the above-mentioned module, and connects to the network interface (plug-in). Event) and a network interface notifies a higher-level application of a disconnection event (plug-out event) from the network. The application 307 is an application that receives an event notification from the NIC monitoring module 306 and performs communication via the Internet 100.

  FIG. 5 is a diagram for explaining an example of the routing table 303 according to the present embodiment.

  In 401, a network address serving as a destination of the packet is described. For example, the route to the LAN segment 104 is described as “2001: 340 :: / 64” (202 in the case of 211 in FIG. 2). When the destination is a default router (default route), “:: / 0” is described as shown in FIG. In 402, a transmission destination gateway (router) of the packet corresponding to 401 is described. For example, in the case of the LAN segment 104, the address “fe80 :: 102” of the router 102 is stored. In 403, a network interface that transmits the corresponding packet is described. Reference numeral 411 represents an example of an entry in the routing table of the terminal 101 connected to the LAN segment 104, and particularly represents an entry of a default router (“:: / 0”). From this entry 411, a packet addressed to the external network transmitted from the terminal 101 is addressed to the address “fe80 :: 102” (link local address of the router 102 (203 in the case of 211 in FIG. 2)) from the network interface “fxp0”. It can be seen that the packet is forwarded.

  FIG. 6 is a diagram showing an example of the default router list 304 according to the present embodiment.

  The default router list 304 is a list that holds router information that is candidates for default routers registered in the routing table 303. These pieces of information hold the router information regarding the router information of the RA transmission source used for the IPv6 address automatic setting function and permitted to be used as the default router. The router information in this list is generally registered and deleted by processing in the kernel.

  In FIG. 6, the address of the router that has transmitted the RA (in FIG. 6, the address “fe80 :: 102” of the router 102 in FIG. 6) is set. Reference numeral 502 denotes a network interface of the terminal 101 (own device) that has received the RA. Here, the network interface 403 (“fxp0”) of FIG. 5 is set. 503 describes the lifetime of this entry (22 minutes 31 seconds in the example of FIG. 6). Reference numeral 511 denotes an entry in the default router list 304 when the terminal 101 is connected to the LAN segment 104.

  When the terminal 101 is connected to the LAN segment 104, by receiving the RA transmitted from the router 102, the address of the router 102 and which network interface of the terminal 101 the router 102 is connected to can be determined. It can be detected. Based on this information, an entry that is a candidate for the default router is created. The survival time 503 is set to an appropriate time (for example, 30 minutes) each time an RA is transmitted almost regularly. As a result, if the next RA is not received within the set time, it is determined that the corresponding router (102 in this case) is not functioning, and the corresponding entry is deleted from the default router list. .

  FIG. 7 is a flowchart for explaining processing by the NIC monitoring module 306 according to the present embodiment.

  First, in step S1, the state of the NIC management 301 is monitored and a change in the NIC state is detected. The flow is divided into the following processes according to the change in the NIC state.

  First, in step S1, when the NIC state changes to “LinkUp” (network connection event), the process proceeds to step S2. As a case of changing to this state, a case where an Ethernet (registered trademark) cable is connected to the network interface of the terminal 101 can be considered. In step S2, the “LinkUp” state is detected, and in step S3, an RS transmission process is performed for the corresponding network interface, and the process ends. That is, when the terminal 101 is connected to the network, a message requesting RS (Router Solicitation): RA (Router Advertise) is transmitted to perform automatic address setting which is an IPv6 function.

  Next, in step S1, when the NIC state changes to “AddressAssign” (automatic address setting), the process proceeds to step S4. As a case of changing to this state, a case where a new IPv6 address is set in the network interface of the terminal 101 can be considered. In step S4, “AddressAssign” is detected, and in step S5, the routing table 303 is monitored, and registration of the default router entry is monitored. If it is confirmed that the default router entry is registered in the routing table 303, the process proceeds to step S6, the plug-in event is notified to the application 307, and the process is terminated. The application 307 that has received this plug-in notification can immediately start communication.

  Finally, in step S1, when the NIC state changes to “LinkDown” (disconnection event with the network), the process proceeds to step S7. As a case of changing to this state, a case where an Ethernet (registered trademark) cable is disconnected from the network interface of the terminal 101 can be considered. If it is detected in step S7 that the link has changed to “LinkDown”, then in step S8, the entry in the default router list 304 is deleted, and synchronization with the routing table 303 is performed. In step S9, a plug-out event is notified to the application 307, and the process ends. The application 307 that has received the plug-out notification can stop the subsequent communication with the Internet 100 and perform processing in the offline state.

  FIG. 8 is a diagram for explaining a plug-in related sequence performed in the NIC monitoring module 306. In particular, FIG. 7 shows a case of processing at the time of detecting the “LinkUp” state (S2) and the time of detecting the “AddressAssign” state (S4).

  The NIC management 301 in the kernel detects that an Ethernet (registered trademark) cable is connected to the network interface of the terminal 101 (701). Since this is an operation in the kernel independent of the processing unit of the present embodiment, the arrow 701 is indicated by a broken line. Hereinafter, the broken-line arrows indicate general processing (performed by the kernel) independent of the processing according to the present embodiment. The monitoring of the NIC management 301 performed by the NIC monitoring module 306 detects that the state of the target network interface has been changed to the “LinkUp” state (702). Then, the process (S2) shown in FIG. 7 is started, and the flow in the case of changing to the “LinkUp” state is executed (703: S2, S3). Then, the RS is transmitted from the target network interface (704). As described above, reference numerals 701 to 704 indicate a sequence at the time of detecting the “LinkUp” state in the flowchart of FIG.

  By transmitting this RS, the router 102 (103) of the LAN segment 104 (105) to which the terminal 101 is connected immediately transmits the RA. Reception of this RA is indicated at 705. The ND management processing 302 in the kernel analyzes the received RA and performs automatic address setting processing (706). In this automatic address setting process, a global address is generated and an address is set for the network interface (707).

  When the address setting for the network interface is performed in this way (707), the NIC monitoring module 306 detects the "AddressAssign" state (708), and enters the "AddressAssign" state based on the processing shown in steps S4 to S6 in FIG. Processing in the case of change is executed (709).

  On the other hand, when the address automatic setting process is performed (706), in addition to the address setting process (707) for the network interface, the RA received in 705 is analyzed and the source of the RA is used as a default router. Check if you can. If it is determined that the router can be used as a default router, each source information of the RA is registered in the default router list 304 (710). Note that the information registered here is the information described with reference to FIG. When the default router list 304 is registered in this way, processing for reflecting the information of the default router list 304 in the routing table 303 is performed (712). By registering the default router in the routing table 303, an entry for the default router is added to the routing table 303 (713). The processing at the time of detecting the “AddressAssign” state (709) detects the registration of the default router in 713 (714). When registration of the default router (default route) in the routing table 303 is detected in this way (714), a plug-in event notification is sent to the upper application 307 (715). Accordingly, the application 307 that has received the event notification starts communication unique to the application (716).

  FIG. 9 is a diagram for explaining a plug-out related sequence performed by the NIC monitoring module 306 according to the present embodiment. In particular, the present invention relates to processing (S7 to S9) at the time of detecting the “LinkDown” state in FIG.

  Reference numeral 801 denotes information on a default router candidate existing in the connected LAN segment. Reference numeral 802 denotes information on a default router existing in the connected LAN segment. That is, reference numerals 801 and 802 indicate a state in which the terminal 101 is connected to a certain LAN segment, address automatic setting is completed, and default router information is correctly set.

  The NIC management 301 in the kernel detects that the LAN segment is disconnected from the network interface of the terminal 101 (803). Then, the monitoring of the NIC management 301 performed by the NIC monitoring module 306 detects that the state of the target network interface has been changed to the “LinkDown” state (804). As a result, the processing shown in FIG. 7 operates and the flow in the case of changing to the “LinkDown” state is executed (805). Through this processing 805, router information that is a candidate for a default router entered in the default router list 304 is deleted (806). With this deletion process, the kernel deletes the default router information in the routing table 303 (807). When the default router list 304 is normally deleted in this way, the NIC monitoring module 306 detects the “LinkDown” state (805), notifies the upper application 307 of the plug-out event (808), The application 307 is notified that the offline state has been entered.

[Other Embodiments]
Although the embodiments of the present invention have been described in detail above, the present invention may be applied to a system composed of a plurality of devices or an apparatus composed of a single device.

  In the present invention, a software program that realizes the functions of the above-described embodiments is supplied directly or remotely to a system or apparatus, and the computer of the system or apparatus reads and executes the supplied program code. In some cases, it can be achieved by In that case, as long as it has the function of a program, the form does not need to be a program. Accordingly, since the functions of the present invention are implemented by computer, the program code installed in the computer also implements the present invention. That is, the present invention includes a computer program itself for realizing the functional processing of the present invention. In this case, the program may be in any form as long as it has a program function, such as an object code, a program executed by an interpreter, or script data supplied to the OS.

  As a storage medium for supplying the program, for example, floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, MO, CD-ROM, CD-R, CD-RW, magnetic tape, nonvolatile memory card ROM, DVD (DVD-ROM, DVD-R) and the like. As another program supply method, a client computer browser is used to connect to an Internet homepage, and the computer program itself of the present invention or a compressed file including an automatic installation function is downloaded from the homepage to a storage medium such as a hard disk. Can also be supplied. It can also be realized by dividing the program code constituting the program of the present invention into a plurality of files and downloading each file from a different homepage. That is, a WWW server that allows a plurality of users to download a program file for realizing the functional processing of the present invention on a computer is also included in the claims of the present invention.

  In addition, the program of the present invention is encrypted, stored in a storage medium such as a CD-ROM, distributed to users, and key information for decryption is downloaded from a homepage via the Internet to users who satisfy predetermined conditions. It is also possible to execute the encrypted program by using the key information and install the program on a computer.

  In addition to the functions of the above-described embodiments being realized by the computer executing the read program, the OS running on the computer based on the instruction of the program may be part of the actual processing or The functions of the above-described embodiment can also be realized by performing all the processing and performing the processing.

  Furthermore, after the program read from the recording medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion board or The CPU or the like provided in the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

  As described above, according to this embodiment, in an Internet mobile terminal device that supports IPv6, even if the network to be connected is switched to another network while the OS of the device is activated, it is connected to the other network. The necessary network can be reconfigured immediately. For this reason, the user can communicate with the network by plug-and-play using an application without being aware of the switching of the network.

It is a figure explaining the network configuration concerning an embodiment of the invention. It is a figure explaining the network information of the router which concerns on embodiment of this invention, a LAN segment, and a terminal. It is a block diagram which shows an example of the hardware constitutions of the terminal which concerns on this Embodiment. It is a figure explaining the module structure of the terminal which concerns on this Embodiment. It is a figure explaining an example of the routing table which concerns on this Embodiment. It is a figure which shows an example of the default router list | wrist which concerns on this Embodiment. It is a flowchart explaining the process inside the NIC monitoring module which concerns on this Embodiment. It is a figure explaining the plug-in related sequence performed in the NIC monitoring module which concerns on this Embodiment. It is a figure explaining the plug-out related sequence performed in the NIC monitoring module which concerns on this Embodiment.

Claims (4)

A communication device having an application capable of communicating with a network,
In response to the address assignment in accordance with the connection with the network, and registration means for registering a default router to the destination of the packet in the network,
And deleting means for deleting a default router in response to disconnect from the network, the destination of the packet in the network that is registered by the registration means,
In response to the registration of the default router by the registration unit, the application is notified of the connection with the network, and the default router registered by the registration unit is deleted by the deletion unit. Notification means for notifying the application of disconnection from the network;
The communication apparatus is characterized in that communication with the network started based on reception of a notification of connection with the network is stopped in response to reception of a disconnection notification from the network . The communication device according to claim 1, wherein the deletion unit deletes the default router registered by the registration unit when the message from the default router is not received within a set time. . A method for controlling a communication device having an application capable of communicating with a network,
A registration step of in response to the address assignment in accordance with the connection with the network, registering a default router to the destination of the packet in the network in a memory,
Depending on disconnected from the network, the deletion step for deleting a default router to the destination of the packet in the network registered in the memory,
In response to the registration of the default router in the registration step, the application is notified of connection with the network, and the default router registered in the registration step is deleted in the deletion step. A notification step of notifying the application of disconnection from the network,
The method for controlling a communication apparatus, wherein the application stops communication with the network that is started based on reception of a notification of connection with the network in response to reception of a disconnection notification from the network . 4. The communication device according to claim 3, wherein the deletion step deletes the default router registered in the memory when a message from the default router is not received within a set time. 5. Control method.

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