JP2007036304A - Mobile communications system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To establish connection via a mobile communication terminal, even if the mobile communication terminal functions as a mobile router of other communication terminals and does not have a direct access means to a router for wireless connection. <P>SOLUTION: The portion from the most significant bit to an IP address prefix out of a first IP address of a destination mobile communication terminal included, as a destination IP address, in an IP packet received from a source mobile communication terminal served by wireless connection is converted into the portion from the most significant bit to an IP address prefix out of a second IP address associated with the first IP address of the destination mobile communication terminal. Based on the destination IP address converted into the second IP address, the received IP packet is routed with respect to to a destination router serving the destination mobile communication terminal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a mobile communication system configured by connecting an access router and a server via a communication network and wirelessly connecting the access router and a mobile communication terminal.

  Conventionally, Mobile IP has been proposed as a method for realizing continuous communication while a mobile terminal (MN: Mobile Node) moves in a network having a different network address in an IP (Internet Protocol) network (non-patent document). Reference 1 and Non-Patent Document 2).

  In Mobile IP, first, when the MN moves from the home network to the external network, the home agent (HA: Home Agent) is notified of the IP address (CoA: Care Of Address) assigned by the connection destination router. Then, the HA holds the correspondence relationship between the IP address (HoA: Home Address) and CoA in the home network of the MN as binding cache information.

  A CN (Correspondent Node) that is a communication partner of the MN uses an HoA that is fixedly assigned to the MN and transmits an IP packet to the MN. The IP packet addressed to the MN is routed to the home network of the MN, received by the HA located on the home network, and encapsulated from the CN toward the current CoA based on the binding cache information. Forward.

  In Mobile IP, a method is also proposed in which the MN directly communicates with the CN without passing through the HA by notifying the CoA to the CN and transmitting the packet to the CoA.

  While Mobile IP is a technology that hides the movement of a mobile terminal from a higher-level application, even when the environment itself moves, such as in a train or in a car, it can move to a communication terminal located inside the mobile terminal. There is network mobility as a technology that conceals communication and realizes continuous communication. For example, when a communication terminal equipped with only a wireless LAN function in a moving train connects to an external network, a wireless access point connected to the external network by a cellular device is installed in the train, and If network mobility technology is installed in the wireless access point, communication terminals in the vehicle can connect to an external network via the wireless access point, and also detect movement in a moving train. Communication is continued without any problem.

  In this way, even within a moving network, there is no need for the communication terminal itself to detect movement, and even if the communication terminal has only a short-range wireless function, By going through the gateway device, it is possible to ensure connectivity to an external network.

  As one method for realizing this network mobility, NEMO Basic Support (hereinafter referred to as NEMO) that extends Mobile IP has been proposed (see Non-Patent Document 3). In NEMO, a mobile router (MR: Mobile Router) that expands an MN includes a network interface to a downstream network in addition to a network interface to an upstream network, and the MR is a communication terminal (LFN :) connected to the downstream network. An IP address that can be aggregated to the HoA of the MR is assigned to (Local Fixed Node).

  Next, the MR transfers all the IP packets sent by the LFN to the HA with IP encapsulation. The HA unpacks the IP capsule and routes it to the destination of the IP packet. Conversely, the HA encapsulates all IP packets addressed to the LFN and forwards them to the MR, and the MR releases the IP capsule and routes it to an appropriate LFN. When the MR moves, it notifies the HA of the CoA acquired at the moving destination in the same way as the normal MN operation, but does nothing for the LFN. Since the IP address assigned to the LFN is an address that can be aggregated into the HoA of the MR, the IP packet transmitted to the LFN inevitably arrives at the HA.

  Thus, even if the connection point of the upstream network of the MR changes, the change due to the movement is concealed in the terminal connected to the downstream network, and the continuation of communication is realized.

  On the other hand, as a mobile communication control system and a mobile communication control method for realizing continuous communication while a mobile communication terminal moves in a method different from Mobile IP in an IP network, there is JP-A-2004-112727 (Patent Document 1). . In Japanese Patent Laid-Open No. 2004-112727, two addresses, a first address that is an identifier of a mobile communication terminal and a second address that is used for intra-network routing, are prepared, and the first address is assigned to the terminal as an invariable address. The second address is generated for each terminal according to the connected router device, and the server device manages the association between the first address and the second address.

  FIG. 9 is a diagram illustrating a configuration example of a mobile communication control system disclosed in Japanese Patent Application Laid-Open No. 2004-112727. First, the mobile communication terminal 900 generates a packet using the first address for both the transmission source and the destination, and transfers the packet to the first access router 901. The first access router 901 refers to the address portion of the received packet and converts it to a second address corresponding to the first address. If the association is not known, the location information management server 902 is inquired. The packet converted to the second address is routed to the third access router 905 to which the destination mobile communication terminal (second mobile communication terminal 906) is connected, and the third access router 905 receives the received packet. The second address portion is converted into a first address and transmitted to the destination mobile communication terminal (second mobile communication terminal) 906.

By doing so, the mobile communication terminal communicates using only the first address, regardless of which router device is connected, and therefore knows the second address indicating the position on the network. There is no. Therefore, unlike Mobile IP, the location information is not leaked to the communication partner, and the communication path is routed at the second address, so that efficient communication is realized.
JP 2004-112727 A "RFC3775 Mobility Support in IPv6" "RFC3344 Mobility Support for IPv4" "RFC3963 Network Mobility (NEMO) Basic Support Protocol"

  However, in the mobile communication control system described in Japanese Patent Application Laid-Open No. 2004-112727, as shown in the above-described example of network mobility, in order for a mobile communication terminal to behave as a mobile router of a peripheral terminal, the following problems are raised: Occurs.

  First, in the mobile communication control system described in Japanese Patent Application Laid-Open No. 2004-112727, it is assumed that a first address is assigned in advance to all mobile communication terminals connected to the network. However, for example, a commercially available PC or PDA equipped with a wireless LAN function does not have an IP address in advance, but uses DHCP (Dynamic Host Configuration Protocol) or router advertisement from the connected IP network after connecting to the wireless LAN network. Then, an IP address is dynamically acquired. In other words, the mobile communication terminal in Japanese Patent Application Laid-Open No. 2004-112727 is managed and operated by a special network that can operate even if a fixed IP address is assigned to the terminal, for example, a specific mobile communication carrier. Limited to terminals directly connected to an IP network.

  In addition, by utilizing an IP address assignment mechanism such as DHCP or router advertisement, it is possible to assign an IP address to a PC or PDA and use it as the first address, but the location information management server manages it. In the IP routing address conversion table, the first address and second address columns of all mobile communication terminals including PCs and PDAs must be managed. There is no problem as long as the number of mobile communication terminals assigned with the first address is within the service provider's expected range. For example, several hundreds of passengers are individually connected to a plurality of wireless LANs in one train. When a function-equipped terminal is to be used, the number of IP routing address conversion table lists becomes enormous and difficult to predict.

  Furthermore, since it is not assumed that the mobile communication terminal itself functions as a mobile router for other terminals, the mobile communication terminal needs to bridge IP packets transmitted and received between the access router and peripheral terminals as a new function. However, it is desirable that communication between peripheral terminals is not performed by bridging to an access router, but is returned by a mobile communication terminal operating as a mobile router. If this is not the case, what is originally required for local communication becomes communication via the access router, and wireless resources between the mobile communication terminal and the access router are wasted.

  Further, when the mobile communication terminal assigned with the first address moves, every time the access router to be connected changes, not only the address conversion table managed by the server is updated, but also the mobile communication of the communication partner The update notification of the second address is also transmitted from the location update server to the access router to which the terminal is connected. Therefore, if there are mobile routers and many wireless LAN function-equipped terminals connected to the same train, and the train moves between access routers one after another, a large number of location update procedures occur. In addition to an increase in server load due to an increase in location update work, address update traffic between the access router and the location update server also increases.

  Even if only one terminal has a globally unique IP address and the terminal under it has only a private IP address, it can communicate with a terminal on an external network via a terminal having a globally unique IP address. NAT (Network Address Translation).

  In NAT, a plurality of terminals are connected under the control of a terminal having a global IP address, a private IP address is assigned to the terminal under the terminal, and a terminal having a global IP address is determined based on an installed conversion table. The destination address and port number of the IP packet sent from the upstream network to the subordinate terminal are rewritten, transferred to the appropriate terminal, and conversely, the IP packet sent from the subordinate terminal to the upstream network is the source address And port number are rewritten and transferred to the upstream network. As a result, a terminal having a global IP address can appear to be transmitting and receiving all IP packets, so that a plurality of terminals can communicate simultaneously with only one global IP address.

  By installing this function in a mobile communication terminal having a first address and assigning a private IP address to a terminal connected to the mobile communication terminal, the number of mobile communication terminals having the first address can be determined. A method of reducing the load related to the update process by concentrating the address update process only on the mobile communication terminal having the first address even during movement is possible.

  However, if a private IP address is assigned to a subordinate terminal, the mobile communication terminal serving as a gateway must monitor the packet header for all IP packets, rewrite the IP address and port number, and conversion processing is concentrated. To do. In addition, since NAT performs conversion by referring only to the IP address portion and the port number portion of the normal IP packet header, nothing is changed with respect to the payload portion of the IP packet. Therefore, an application that uses a protocol that embeds the IP address of the terminal itself in the payload portion does not operate, or conversion processing for each protocol needs to be implemented in the mobile communication terminal.

  On the other hand, unlike Japanese Patent Application Laid-Open No. 2004-112727, NEMO Basic Support only needs to notify the HA of the CoA generated by the MR after movement to the HA, so that the load for updating the position information can be reduced. However, since all communication goes between HA and MR, the communication path is redundant, and since IP packets are encapsulated and transmitted / received, the IP packet length increases, the processing load due to encapsulation processing increases, This causes a problem of an increase in transfer speed.

  The present invention has been made in view of such circumstances, and a mobile communication terminal functions as a mobile router of another communication terminal, and has direct access means to a router device to which the mobile communication terminal is wirelessly connected. Even if there is no communication terminal, it is possible to connect via the mobile communication terminal, and as long as the communication terminal moves together with the mobile communication terminal, communication can be continued, while avoiding redundant communication paths and efficiency of the address conversion table. It is an object of the present invention to provide a mobile communication system capable of preventing general management and further leakage of current location information of a mobile communication terminal.

  (1) In order to achieve the above object, the present invention takes the following measures. In other words, the source router device according to the present invention uses the first IP address for identifying the mobile communication terminal and the second IP address for routing the IP packet, so that the source mobile device that is the source A source router apparatus applied to a mobile communication system that realizes mobile communication between a communication terminal and a destination mobile communication terminal that is a destination, wherein the first IP address and the second IP of the destination mobile communication terminal An IP address storage unit for storing an address and an IP address prefix length in association with each other, and the destination mobile communication terminal included as a destination IP address in an IP packet received from a wirelessly connected source mobile communication terminal Part of the first IP address of the first IP address from the most significant bit to the IP address prefix length Of the second IP address associated with the first IP address of the communication terminal, an address conversion unit that converts the most significant bit to the IP address prefix length, and the second IP address A routing unit that routes the received IP packet to a destination router device under the control of the destination mobile communication terminal based on the destination IP address.

  In this way, from the first IP address of the destination mobile communication terminal included as the destination IP address in the IP packet received from the subordinate source mobile communication terminal, the IP from the most significant bit The part up to the address prefix length is converted into the part from the most significant bit to the IP address prefix length of the second IP address associated with the first IP address of the destination mobile communication terminal, Since the received IP packet is routed to the destination router device based on the IP address, the mobile communication terminal can function as a mobile router of another communication terminal, and direct access means to the source router device is provided. Even a communication terminal that does not have a connection to a source router device via a mobile communication terminal is possible. In addition, communication can be continued as long as the communication terminal moves together with the mobile communication terminal. Furthermore, redundant communication paths can be avoided, and even when a large number of communication terminals are connected to the mobile communication terminal, the address conversion table by the server device can be managed efficiently. It is also possible to prevent leakage of the current location information of the mobile communication terminal.

  (2) In addition, the source router device according to the present invention provides the destination mobile communication terminal of the destination mobile communication terminal included as a destination IP address in an IP packet received from the wirelessly connected subordinate source mobile communication terminal. When the second IP address of the destination mobile communication terminal associated with the first IP address is not stored in the IP address storage unit, the second IP of the destination mobile communication terminal is sent to the server device. An inquiry unit that inquires about the address and the IP address prefix length is further provided.

  As described above, when the second IP address associated with the first IP address of the destination mobile communication terminal included in the received IP packet is not stored in the IP address storage unit, The mobile communication terminal can function as a mobile router for other communication terminals, and even a communication terminal that does not have a direct access means to the call source router can be transmitted via the mobile communication terminal. Connection to the original router device becomes possible. In addition, communication can be continued as long as the communication terminal moves together with the mobile communication terminal.

  (3) Further, the destination router apparatus according to the present invention uses the first IP address for identifying the mobile communication terminal and the second IP address for routing the IP packet, so that the source router A destination router apparatus applied to a mobile communication system that realizes mobile communication between an original mobile communication terminal and a destination mobile communication terminal that is a destination, wherein the first IP address and the second IP address of the destination mobile communication terminal An IP address storage unit that associates and stores an IP address and an IP address prefix length, and the destination movement included as a destination address in an IP packet received from a source router device under the control of the source mobile communication terminal Of the second IP address of the communication terminal, the portion from the most significant bit to the IP address prefix length is the destination Of the first IP address associated with the second IP address of the mobile communication terminal, an address conversion unit that converts the most significant bit to the IP address prefix length, and the first IP address A packet transfer unit configured to transfer the received IP packet to a subordinate destination mobile communication terminal that is wirelessly connected based on the converted destination address.

  In this way, from the second IP address of the destination mobile communication terminal included as the destination address in the IP packet received from the source router apparatus under the control of the source mobile communication terminal, the IP from the most significant bit The portion up to the address prefix length is converted into the portion from the most significant bit to the IP address prefix length of the first IP address associated with the second IP address of the destination mobile communication terminal, Since the IP packet received based on the IP address is transferred to the destination mobile communication terminal, a redundant communication path can be avoided, and the server device can be used even when a large number of communication terminals are connected to the mobile communication terminal. Can efficiently manage the address conversion table. It is also possible to prevent leakage of the current location information of the mobile communication terminal.

  (4) Further, the destination router device according to the present invention, when wirelessly connected to the destination mobile communication terminal, the second address of the destination mobile communication terminal to be associated with the first IP address of the destination mobile communication terminal An address notification unit that selects an IP address and notifies the server device of the selected second IP address is further provided.

  As described above, when wirelessly connected to the destination mobile communication terminal, the second IP address of the destination mobile communication terminal to be associated with the first IP address of the destination mobile communication terminal is selected, and the selected second IP address is selected. Since the server apparatus is notified, redundant communication paths can be avoided, and even when a large number of communication terminals are connected to the mobile communication terminal, the address conversion table by the server apparatus can be efficiently managed. .

  (5) Further, an access router apparatus according to the present invention includes the source router apparatus according to claim 1 or claim 2 and the destination router apparatus according to claim 3 or claim 4.

  With this configuration, the mobile communication terminal can function as a mobile router for other communication terminals, and even a communication terminal that does not have a direct access means to the source router device can be connected via the mobile communication terminal. Connection to the device is possible. In addition, communication can be continued as long as the communication terminal moves together with the mobile communication terminal. Furthermore, redundant communication paths can be avoided, and even when a large number of communication terminals are connected to the mobile communication terminal, the address conversion table by the server device can be managed efficiently. It is also possible to prevent leakage of the current location information of the mobile communication terminal.

  (6) A mobile communication terminal according to the present invention is a mobile communication terminal that is wirelessly connected to an access router device, has a gateway function, and routes IP packets to the subordinate communication terminal and the router device. A terminal-side address storage unit that stores the first IP address and the IP address prefix length as an identifier of the local station in association with each other, and the IP address prefix length from the most significant bit of the first IP address. An address assignment unit that assigns to the subordinate communication terminal an IP address that differs only in lower bits than the part up to and including the IP packet received from the subordinate communication terminal based on the assigned IP address Routed to the device and received from the access router device The IP packet is characterized by and a terminal side routing unit for routing to the appropriate communication terminals under the.

  With this configuration, the mobile communication terminal can function as a mobile router for other communication terminals, and even a communication terminal that does not have a direct access means to the source router device can be connected via the mobile communication terminal. Connection to the device is possible. In addition, communication can be continued as long as the communication terminal moves together with the mobile communication terminal.

  (7) Further, the server device according to the present invention uses a first IP address for identifying a mobile communication terminal and a second IP address for routing an IP packet, and is a source that is a source. A server apparatus applied to a mobile communication system that realizes mobile communication between a mobile communication terminal and a destination mobile communication terminal as a destination, wherein the first IP address and the second IP address of the destination mobile communication terminal And the address management unit that manages the IP address prefix length in association with each other, and the source router device under the control of the source mobile communication terminal, the first IP address and the second of the destination mobile communication terminal And an instruction unit for instructing to store the IP address and the IP address prefix length in association with each other.

  In this way, for the source router device under the control of the source mobile communication terminal, the first IP address, the second IP address, and the IP address prefix length of the destination mobile communication terminal are stored in association with each other. Therefore, redundant communication paths can be avoided, and the address conversion table can be efficiently managed even when a large number of communication terminals are connected to the mobile communication terminal.

  (8) The mobile communication system according to the present invention connects the access router device according to claim 5 and the server device according to claim 7 via a communication network, and the access router device and claim 6. This is a feature that is configured by wirelessly connecting the described mobile communication terminal.

  With this configuration, the IP from the most significant bit of the first IP address of the destination mobile communication terminal included as the destination IP address in the IP packet received from the source mobile communication terminal under wireless connection The part up to the address prefix length is converted into the part from the most significant bit to the IP address prefix length of the second IP address associated with the first IP address of the destination mobile communication terminal, Since the received IP packet is routed to the destination router device based on the IP address, the mobile communication terminal can function as a mobile router of another communication terminal, and direct access means to the source router device is provided. Even a communication terminal that does not have a connection to a source router device via a mobile communication terminal is possible. In addition, communication can be continued as long as the communication terminal moves together with the mobile communication terminal. Furthermore, redundant communication paths can be avoided, and even when a large number of communication terminals are connected to the mobile communication terminal, the address conversion table by the server device can be managed efficiently. It is also possible to prevent leakage of the current location information of the mobile communication terminal.

  According to the present invention, even if the mobile communication terminal functions as a mobile router of another communication terminal and the mobile communication terminal does not have a direct access means to the router device to which the mobile communication terminal is wirelessly connected, the mobile communication terminal Connection via is possible. Further, communication can be continued as long as the communication terminal moves together with the mobile communication terminal, and a redundant communication path can be avoided. And even when a large number of communication terminals are connected, it is possible to efficiently manage the address translation table by the server device, and further prevent leakage of the current location information of the mobile communication terminal. Become.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a mobile communication system according to an embodiment of the present invention. The mobile communication system includes, for example, a location information management server 100, a first mobile communication terminal 101, a second mobile communication terminal 108, a first communication terminal 102, a second communication terminal 103, and a first access router 104. , Second access router 105, third access router 107, router 106, and network 109. In this specification, a router and a router device are synonymous, and an access router and an access router device are synonymous.

  In the mobile communication system according to the present embodiment, two types of IP addresses are used, one is an IP host address (first IP address) as an identifier of the mobile communication terminal, and the other is It is an IP routing address (second IP address) for use in routing IP packets. There is a one-to-one correspondence between an IP host address and an IP routing address. The IP host address is an IP address fixedly assigned to the mobile communication terminal, and the IP routing address is an access to which the mobile communication terminal is connected. IP address assigned by the router. Either IP address may be an IPv6 address or an IPv4 address, but in this embodiment, the use of an IPv6 address will be described as an example.

  The location information management server 100 is a server that is connected to the network 109 and manages the IP host address, IP routing address, and IP address prefix length of the mobile communication terminal connected to the network 109 in association with each other. As shown in FIG. 2, the location information management server 100 includes an IP address update unit 701, a router connection communication interface 702, an IP address conversion table 703, and an IP address management unit 704.

  In FIG. 2, an IP address management unit 704 is a management unit that manages the association between the IP routing address and the IP host address described above, and is connected to an IP address conversion table 703 that is a database that stores the association. In response to an instruction from the IP address management unit 704, the IP address update unit 701 instructs the access router to update the association between the IP host address and the IP routing address. The router connection communication interface 702 is a communication interface for performing a wired connection with an access router connected to the network 109, such as an Ethernet adapter, but is not limited thereto, and addresses are associated with the access router. It is a communication interface for receiving an update instruction and an inquiry from the access router.

  The network 109 is a network constructed by the Internet protocol.

  The router 106 has a function of transferring the received packet to another appropriate router or access router according to the destination address of the IP packet. FIG. 3 is a configuration diagram of the router 106, and the router 106 includes a routing unit 501 and network communication interfaces 502 and 503. The network communication interfaces 502 and 503 receive a packet from each connected network, transfer the packet to the routing unit 501, and transfer the packet to an appropriate network communication interface according to the destination IP address of the packet. For example, although it is an Ethernet adapter etc., it does not specifically limit to this.

  The first access router 104, the second access router 105, and the third access router 107 have a function of forwarding the received packet to other appropriate routers and access routers according to the destination address in the same manner as the router 106. Have. In addition, an address conversion function for converting an IP host address portion included in a destination address and a source address of an IP packet received from a mobile communication terminal into an IP routing address, and a mobile communication terminal received from the network 109 An address conversion function is provided for converting an IP routing address portion included in the destination address and the source address of the destination IP packet into an IP host address.

  FIG. 4 is a configuration diagram of the first access router 104. The first access router 104 includes an IP address storage unit 601, an IP address conversion table 602, a routing unit 603, a network communication interface 604, a location information management server connection communication interface 605, a mobile communication terminal communication interface 606, an IP address conversion. 607, a packet transfer unit 608, and an IP address notification / inquiry unit 609.

  The IP address storage unit 601 is a storage unit that temporarily stores an IP host address of a mobile communication terminal in association with an IP routing address corresponding to the IP host address. The IP address conversion table 602 is a database used for the storage. The routing unit 603 performs IP packet routing. The network communication interface 604 is a communication interface used by the access router to connect to the network 109, and is, for example, an Ethernet adapter. The location information management server connection communication interface 605 is a communication interface for the access router to update the IP address of the mobile communication terminal and to make an inquiry to the location information management server. For example, it is an Ethernet adapter, but is not limited to this. .

  The mobile communication terminal communication interface 606 is a communication interface for performing wireless communication with the mobile communication terminal, and is a communication interface such as W-CDMA, for example, but is not a direct W-CDMA communication interface, for example, It may be an interface for connecting to a W-CDMA base station apparatus. The IP address conversion unit 607 converts the IP host address portion of the packet received from the mobile communication terminal into an IP routing address, and conversely converts the IP routing address portion of the packet received from the network communication interface into an IP host address. . The packet transfer unit 608 transfers the packet received from the mobile communication terminal communication interface to the IP address conversion unit, or conversely transfers the packet whose address has been converted by the IP address conversion unit to the mobile communication terminal communication interface. Is. The IP address notification / inquiry unit 609 makes an inquiry to the location information management server when the IP address conversion unit does not have the IP address table information to be converted, and assigns an IP routing address to the connected mobile communication terminal. At this time, the assigned address is notified to the position information management server.

  Note that the second access router 105 and the third access router 107 have the same configuration as the first access router.

  The first mobile communication terminal 101 is a mobile terminal such as a mobile phone, and is configured as shown in FIG. A mobile communication terminal communication interface 204 for connecting to the network 109 via an access router, and a wireless LAN interface 203 for providing a function as a gateway of other peripheral communication terminals. I have. For example, the mobile communication terminal communication interface 204 is a cellular communication interface such as W-CDMA, but is not particularly limited as long as it is an interface capable of communicating with an access router. The wireless LAN interface 203 is a wireless LAN interface such as IEEE802.11b. However, the wireless LAN interface 203 is not particularly limited thereto, and may be a different type of communication interface from the mobile communication terminal communication interface 204.

  The IP address storage unit 201 is a storage unit for holding the IP host address and the IP address prefix length assigned to the mobile communication terminal. The IP address assignment unit 202 assigns an IP address to another communication terminal via the wireless LAN interface based on the IP host address and the IP address prefix length held in the IP address storage unit 201. The routing unit 205 routes a packet that is not addressed to itself among the packets received from the communication interface for mobile communication terminals to the destination mobile terminal using the wireless LAN interface, or conversely among packets received from the mobile terminal. A packet that is not addressed to itself is routed to an access router by using a communication interface for mobile communication terminals.

  FIG. 6 is a block diagram showing a schematic configuration of the second mobile communication terminal. Unlike the first mobile communication terminal 101, the second mobile communication terminal 108 does not have a wireless LAN interface. The IP address storage unit 301 is the same as the IP address storage unit 201 of the first mobile communication terminal 101. The mobile communication terminal communication interface 302 is the same as the mobile communication terminal communication interface 204 of the first mobile communication terminal 101.

  The first communication terminal 102 is a communication terminal such as a PC or a PDA, but is not limited thereto, and is a terminal that has a wireless LAN interface function and can communicate with the Internet protocol. The first communication terminal 102 includes an IP address storage unit 401 and a wireless LAN interface 402 as shown in FIG. The IP address storage unit 401 is a device that stores the IP address assigned by the IP address assignment unit 202 of the first mobile communication terminal 101, and the first communication terminal 102 uses the IP address stored here as its own. Communication is performed with the IP address of The wireless LAN interface 402 is a wireless LAN interface such as IEEE802.11b. However, the wireless LAN interface 402 is not particularly limited, and may be a communication interface of the same type as the wireless LAN interface of the first mobile communication terminal 101. Note that the second communication terminal 103 is configured similarly to the first communication terminal 102.

Next, the operation of the mobile communication system according to the present embodiment configured as described above will be described. In FIG. 1, for the first mobile communication terminal 101 functioning as a gateway for other communication terminals, as an IP host address, as an IPv6 address,
“2020: 2020: 1FFF: 1”
And 48 bits are assigned in advance as the IP address prefix length. In addition, for the second mobile communication terminal 108 that communicates alone, as an IP host address,
“2020: 2020: 1000: 1000: # 2”
And 128 bits are assigned in advance as the IP address prefix length. # 2 is a character used for convenience of explanation, and is actually a 64-bit numeric string serving as a terminal identifier. In the present embodiment, the IP host address and the IP address prefix length are handled as information fixedly incorporated in the terminal in advance. However, for example, the service provider of the mobile communication system can rewrite the IP address storage unit of the mobile communication terminal according to the request of the owner or the subscription of a new service.

When the first mobile communication terminal 101 connects to the first access router 104,
“2020: 2020: 0001: 1”
And the second mobile communication terminal 108 connects to the third access router 107, as an IP routing address,
“2020: 2020: 0FFF: 1010: # 2” is assigned. Here, # 2 is a numerical value having the same 64-bit length as # 2 included in the IP host address of the second mobile communication terminal 108.

  These IP host address, IP routing address, and IP address prefix length are stored in the IP address storage unit 601 in the first access router 104, and further via the location information management server connection communication interface 605. The information management server 100 is notified. The IP address management unit 704 in the location information management server 100 records information associated with the IP host address, IP routing address, and IP address prefix length notified to the IP address conversion table 703. The address conversion table in FIG. 8 shows recorded information.

  Note that the IP routing address assigned to the first mobile communication terminal 101 and the second mobile communication terminal 108 by the first access router 104 is an address at which packets are routed to the assigned access routers in the network 109. is there.

Next, the first mobile communication terminal 101 assigns IP addresses necessary for communication to the first communication terminal 102 and the second communication terminal 103 existing in the vicinity. Since the IP host address and IP address prefix length of the first mobile communication terminal 101 are stored in the IP address storage unit 201, the IP address assignment unit 202 of the first mobile communication terminal 101 is based on the information. The IPv6 network prefix is
“2020: 2020: 1FFF: 0001”,
The router advertisement having an IP address prefix length of 64 bits is transmitted to the first communication terminal 102 and the second communication terminal 103 using the wireless LAN interface 203. This router advertisement is one of IPv6 address automatic assignment mechanisms. When a router periodically transmits a packet for the purpose of assigning an IPv6 address to a subordinate terminal, the IPv6 terminal that has received the packet transmits the received IPv6 network. An IPv6 address is generated based on the prefix, the address prefix length, and its own MAC address. At this time, the IPv6 network prefix received by the router advertisement is used for the network address portion of the generated IPv6 address.

The first communication terminal 102 and the second communication terminal 103 receive the router advertisement via the wireless LAN interface 402 and generate an IPv6 address. Here, the first communication terminal 102 is “2020: 2020: 1FFF: 0001: # 3”,
The second communication terminal 103 is “2020: 2020: 1FFF: 0001: # 4”,
Is generated. Then, the generated IP address is stored in the IP address storage unit 401.

Next, it is assumed that the first communication terminal 102 that has acquired the IP address communicates with the second mobile communication terminal 108. First, in the first communication terminal 102, the destination address is the IP host address of the second mobile communication terminal 108.
“2020: 2020: 1000: 1000: # 2”,
The source address is the IPv6 address of the first communication terminal 102.
“2020: 2020: 1FFF: 0001: # 3”,
Is transmitted to the first mobile communication terminal 101 via the wireless LAN interface 402.

  The first mobile communication terminal 101 receives the IP packet via the wireless LAN interface 203 and transfers it to the routing unit 205. The routing unit 205 recognizes that the destination of the packet is not addressed to itself, and transmits the packet from the mobile communication terminal communication interface 204 toward the first access router 104. If this packet is destined for itself, the packet is not transferred but processed in the terminal.

  If the network prefix portion of the destination address (the portion of the IP address up to the IP address prefix length counted from the top) is the same as its own network prefix, the packet is connected to the first mobile communication terminal 101. Since it can be determined that the packet is addressed to the communication terminal, the packet is transmitted to the appropriate communication terminal via the wireless LAN interface 203.

  The first access router 104 receives the packet at the mobile communication terminal communication interface 606 and transfers the packet to the IP address conversion unit 607 via the packet transfer unit 608. The IP address conversion unit 607 accesses the IP address conversion table via the IP address storage unit 601, and refers to how to convert the IP host address of the received packet into an IP routing address.

  If the information can be referred to here, the information is adopted. If the information cannot be referred to, the location information management server 100 is inquired from the IP address notification / inquiry unit 609 using the location information management server connection communication interface. The IP address management unit 704 of the location information management server 100 accepts the inquiry and refers to the IP address conversion table 703 to set the combination of the IP host address, the IP routing address, and the IP address prefix length to the first access router 104. Notify

  The IP address conversion unit 607 of the first access router 104 converts the IP host address portion of the received packet into an IP routing address based on the updated IP address conversion table 602.

First, the destination address is the IP host address of the second mobile communication terminal 108.
“2020: 2020: 100: 1000: # 2”,
Based on the IP address conversion table 602,
Conversion to “2020: 2020: 0FFF: 1010: # 2”.

For the source address,
“2020: 2020: 1FFF: 0001: # 3”,
The IP host address of the first mobile communication terminal 101 matches the IP address prefix length (48 bits) of the IP host address of the first mobile communication terminal 101, so that the IP address is counted from the most significant IP host address of the source address. Rewrite only the prefix length part to the IP routing address of the first mobile communication terminal 101,
It is assumed that “2020: 2020: 0001: 0001: # 3”.
The rewritten IP packet is transferred to the routing unit 603 and transferred to the network 109 via the network communication interface 604.

  In the network 109, the IP packet is transferred based on the IP routing address written in the destination address, passes through the router 106, and arrives at the third access router 107, which is an appropriate access router.

In the third access router 107, the IP packet is first transferred to the routing unit 603 via the network communication interface 604, and the IP address conversion unit converts the IP routing address into the IP host address. In this case as well, the IP address storage unit 601 is queried in the same manner as described above, and if it is possible to refer to how to convert in the IP address conversion table, that information is used. The location information management server is inquired via the management server connection communication interface 605 to acquire information. Then, the IP address conversion unit 607 converts the IP routing address of the received IP packet into an IP host address based on the acquired conversion table. Refer to the conversion table for the destination address.
“2020: 2020: 0FFF: 1010: # 2”,
Is found to be the IP routing address of the second mobile communication terminal 108,
“2020: 2020: 1000: 1000: # 2”,
To the IP host address of the second mobile communication terminal 108.

On the other hand, for the source address,
“2020: 2020: 0001: 0001: # 3”,
The IP routing address is equal to the IP address prefix length (48 bits) of the IP routing address of the first mobile communication terminal 101. Therefore, the IP address is counted from the highest IP routing address of the source address. Only the prefix length part is rewritten to the IP host address of the first mobile communication terminal 101,
“2020: 2020: 1FFF: 0001: # 3”.

  The IP packet with the rewritten address is transferred to the packet transfer unit 608 and transmitted from the mobile communication terminal communication interface to the second mobile communication terminal 108. As a result, the second mobile communication terminal 108 can communicate with the first communication terminal 102.

  On the other hand, communication from the second mobile communication terminal 108 to the first communication terminal 102 is performed according to a procedure completely opposite to the above description.

Next, it is assumed that the first mobile communication terminal 101 moves together with the first communication terminal 102 and the second communication terminal 103 and moves under the control of the second access router 105. The first mobile communication terminal 101 acquires a new IP routing address from the second access router 105 that is the movement destination. Here, for example,
“2020: 2020: 0002: 1”,
Is obtained. Then, the second access router 105 notifies the updated IP address conversion table to the location information management server 100 and the third access router 107 connected to the second mobile communication terminal 108 of the communication partner. The subsequent communication is performed by the same method as described above.

  As described above, first, the mobile communication terminal can function as a mobile router of another communication terminal, and even if the mobile communication terminal moves together with another communication terminal, the movement is hidden in the communication terminal. Therefore, there is no need to change the destination address or source address of the packet to be transmitted / received.

  In addition, by incorporating the IP address prefix length into the IP address conversion table, the number of IP address conversion tables that must be managed even if a large number of communication terminals are connected to the mobile communication terminal It is enough for the terminal. Furthermore, since the IP addresses used by the mobile communication terminal and the communication terminal connected thereto are all IP host addresses or addresses automatically generated therefrom, the IP routing address indicating the position information is not leaked.

  In this embodiment, when the first mobile communication terminal 101 assigns IP addresses to the first communication terminal 102 and the second communication terminal 103, the assignment by the router advertisement is used. The IP address may be based on DHCP (Dynamic Host Configuration Protocol), but not limited to this, and any IP address that can be aggregated to the first mobile communication terminal 101 is not limited thereto. An address assignment method may be used.

  As described above, according to the mobile communication system according to the present embodiment, the mobile communication terminal functions as a mobile router of another communication terminal, and the mobile communication terminal does not have a direct access means to the router to which wireless connection is established. Even a communication terminal can be connected via a mobile communication terminal, can continue communication as long as the communication terminal moves together with the mobile communication terminal, can avoid redundant communication paths, and has a large number of communication terminals. Even when connected, it is possible to efficiently manage the address conversion table by the server and to prevent leakage of the current location information of the mobile communication terminal.

It is the figure which showed schematic structure of the mobile communication system. It is the block diagram which showed schematic structure of the positional infomation management server. It is the block diagram which showed schematic structure of the router. It is the block diagram which showed schematic structure of the 1st-3rd access router. It is the block diagram which showed schematic structure of the 1st mobile communication terminal. It is the block diagram which showed schematic structure of the 2nd mobile communication terminal. It is the block diagram which showed schematic structure of the 1st and 2nd communication terminal. It is a figure which shows an address conversion table. It is the block diagram which showed schematic structure of the mobile communication system currently disclosed by Unexamined-Japanese-Patent No. 2004-112727.

Explanation of symbols

100 location information management server 101 first mobile communication terminal 102 first communication terminal 103 second communication terminal 104 first access router 105 second access router 106 router 107 third access router 108 second mobile communication Terminal 109 Network 201 IP address storage unit 202 IP address assignment unit 203 Wireless LAN interface 204 Mobile communication terminal communication interface 205 Routing unit 301 IP address storage unit 302 Mobile communication terminal communication interface 401 IP address storage unit 402 Wireless LAN interface 501 Routing Units 502 and 503 Network communication interface 601 IP address storage unit 602 IP address conversion table 603 Routing unit 604 Network communication interface 605 Location information management server connection communication interface 606 Mobile communication terminal communication interface 607 IP address conversion unit 608 Packet transfer unit 609 IP address notification / inquiry unit 701 IP address update unit 702 Router connection communication interface 703 IP address conversion table 704 IP address management Part

Claims (8)

Using the first IP address for identifying the mobile communication terminal and the second IP address for routing the IP packet, the source mobile communication terminal as the source and the destination mobile communication terminal as the destination A source router device applied to a mobile communication system for realizing mobile communication,
An IP address storage unit that associates and stores the first IP address, the second IP address, and the IP address prefix length of the destination mobile communication terminal;
The IP address from the most significant bit of the first IP address of the destination mobile communication terminal included as the destination IP address in the IP packet received from the source mobile communication terminal under wireless connection An address conversion unit that converts a part up to the prefix length into a part from the most significant bit to the IP address prefix length of the second IP address associated with the first IP address of the destination mobile communication terminal When,
A routing unit configured to route the received IP packet to a destination router device under control of the destination mobile communication terminal based on the destination IP address converted to the second IP address. The source router device.   The destination mobile communication terminal associated with the first IP address of the destination mobile communication terminal included as a destination IP address in an IP packet received from a source mobile communication terminal under the wireless connection When the second IP address is not stored in the IP address storage unit, the server further includes an inquiry unit that inquires the server device about the second IP address and IP address prefix length of the destination mobile communication terminal. The source router device according to claim 1, wherein: Using the first IP address for identifying the mobile communication terminal and the second IP address for routing the IP packet, the source mobile communication terminal as the source and the destination mobile communication terminal as the destination A destination router device applied to a mobile communication system for realizing mobile communication,
An IP address storage unit that associates and stores the first IP address, the second IP address, and the IP address prefix length of the destination mobile communication terminal;
Of the second IP address of the destination mobile communication terminal included in the IP packet received from the source router apparatus under the source mobile communication terminal as the destination address, the IP from the most significant bit Address conversion for converting a part up to the address prefix length into a part from the most significant bit to the IP address prefix length in the first IP address associated with the second IP address of the destination mobile communication terminal And
A packet transfer unit that transfers the received IP packet to a wirelessly connected destination mobile communication terminal based on the destination address converted to the first IP address. Router device.   When wirelessly connected to the destination mobile communication terminal, the second IP address of the destination mobile communication terminal to be associated with the first IP address of the destination mobile communication terminal is selected, and the selected second IP address is 4. The destination router device according to claim 3, further comprising an address notification unit that notifies the server device.   An access router device comprising: the source router device according to claim 1 or 2; and the destination router device according to claim 3 or 4. A mobile communication terminal that wirelessly connects to an access router device, has a gateway function, and performs routing of IP packets to the router device,
A terminal-side address storage unit for storing the first IP address as an identifier of the own station and the IP address prefix length in association with each other;
An address allocating unit that allocates, to the subordinate communication terminal, an IP address that is different only in bits lower than the portion from the most significant bit to the IP address prefix length of the first IP address;
A terminal for routing an IP packet received from the subordinate communication terminal to the access router device based on the assigned IP address and routing an IP packet received from the access router device to the subordinate communication terminal A mobile communication terminal comprising: a side routing unit. Using the first IP address for identifying the mobile communication terminal and the second IP address for routing the IP packet, the source mobile communication terminal as the source and the destination mobile communication terminal as the destination A server device applied to a mobile communication system for realizing mobile communication,
An address management unit that manages the first IP address, the second IP address, and the IP address prefix length of the destination mobile communication terminal in association with each other;
Storing the first IP address, the second IP address, and the IP address prefix length of the destination mobile communication terminal in association with each other in a source router device under the control of the source mobile communication terminal An instruction unit for instructing the server device.   The access router device according to claim 5 and the server device according to claim 7 are connected via a communication network, and the access router device and the mobile communication terminal according to claim 6 are wirelessly connected. A mobile communication system.

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