JP3936366B2 - Communication apparatus and communication method - Google Patents

Description

  The present invention relates to a communication device and a communication method for performing communication with a mobile terminal device.

The Mobile Internet Protocol (hereinafter referred to as “MIP” as appropriate) delivers an IP packet to a mobile terminal device (hereinafter referred to as “MN” as appropriate) connected to an arbitrary network while using a permanent IP address. It provides a mechanism. A feature of this communication method using MIP is that a home agent existing on the home link receives a packet addressed to the MN on its behalf and delivers it to the moving MN (for example, see Non-Patent Document 1). ).
For example, in the co-located mode as shown in FIG. 16, that is, when there is no foreign agent on the communication network 101, it is addressed to the MN 103 transmitted from a fixed communication terminal apparatus (hereinafter referred to as “CN” as appropriate) 102 When the home agent 105 receives the packet by proxy, the following processing is performed.

  First, when the MN 103 moves from the same segment as the home agent 105 (hereinafter referred to as a home link 107) to the external link 108, Registration Request and Registration Reply are transmitted and received.

  When the registration of the MN 103 is successful, the home agent 105 issues a gratuitous ARP by broadcasting.

  Further, when the CN 102 having no ARP entry addressed to the MN 103 performs IP communication with the MN 103, the CN 102 issues an ARP Request addressed to the IP of the MN and attempts to resolve the MAC address.

  In response to this ARP Request, the home agent 105 sends back a Proxy ARP of the moving MN 103 as a proxy. The CN 102 that has received the Proxy ARP packet changes the MAC address of the MN 103 in its own ARP table to the MAC address of the home agent 105 as shown in FIG. As a result, the home agent 105 can receive the packet.

  Further, as shown in FIG. 17, when the foreign agent 106 exists in the FA mode, that is, on the communication network 101, the only difference from the above-mentioned Co-located mode is that the operation on the external link 108 side is different. The process of proxy reception of packets on the home link 107 side is the same as that described above.

  In the external link 108, Router Soliciaton and Router Advertisement for searching the foreign agent 106 are transmitted and received, and Registration Request and Registration Reply pass through the foreign agent 106, but the operation seen from the home link 107 side is the above. It is the same as the case of.

Note that when the moving MN 103 returns to the home link 107, the packet addressed to the MN 103 continues to be transmitted to the home agent 105 as it is, so that the MN 103 is connected to the home link 107 as shown in FIG. Issue Gratuitous ARP again when reconnected to.
The CN 102 that has received the ARP packet changes the destination of the packet from the home agent 105 to the original MN 103, and thus can directly communicate with the MN 103.

  Also, if a Registration Request cancellation request is issued and the cancellation is successful, the home agent 105 does not execute an ARP proxy response.

Therefore, the MN 103 that has returned to the home link 107 operates as a normal terminal.
Nokia Research Center, “IP Mobility Support for IPv4”, RFC3344, August 2002.

  However, in the communication network 101 as described above, the ARP table of the CN 102 is rewritten by transmitting Gratuitous ARP and Proxy ARP as described above. That is, since the proxy reception is performed by camouflaging the address of the data link layer, the following problems exist (see FIG. 20).

  First, when the quantity of the MN 103 increases, the number of broadcast packets (ARP packets) transmitted and received increases accordingly, and the bandwidth usage rate in the home network 107 increases.

  Secondly, if the MN 103 moves, that is, leaves the home network 107 and returns to it frequently, it is necessary to rewrite the ARP table each time, and this requires a certain amount of time. Therefore, a time lag occurs before the packet can be transmitted to an appropriate transmission destination. Therefore, reliable and immediate communication cannot be performed.

  Third, when the CN 102 cannot receive the ARP for some reason, the home agent 105 cannot receive the packet by proxy because the packet is transmitted to the MAC address of the MN 103 in the ARP table. For this reason, until the entry addressed to the MN 103 disappears from the ARP table of the CN 102 (the entry, that is, the IP address is deleted from the ARP table if communication addressed thereto is not performed for a predetermined time), communication with the MN 103 is not performed. I can't do it.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a communication device and a communication method capable of performing proxy reception of a packet without performing data link layer camouflaging. .

  The present invention according to claim 1 is a registration request receiving step of receiving a registration request from a mobile terminal device existing in the same segment as the home agent, and an IP address and a MAC address of the mobile terminal device based on the registration request And a communication process for directly communicating with a mobile terminal device using a MAC address.

  According to the present invention, it is possible to perform proxy reception of packets without performing data link layer camouflaging.

  Hereinafter, a communication apparatus and a communication method of the present invention will be described with reference to the drawings.

  The following examples are only for the purpose of explaining the present invention and do not limit the scope of the present invention. Accordingly, those skilled in the art can employ various embodiments including each or all of these elements, and these embodiments are also included in the scope of the present invention.

  In all the drawings for explaining the following embodiments, the same reference numerals are given to the same elements, and the repeated explanation thereof is omitted.

  First, the concept of the communication network 1 according to an embodiment of the present invention will be described with reference to FIG.

  As shown in the figure, the communication network 1 of the present invention comprises a CN 2, a router 3, MNs 4 a to 4 d (hereinafter collectively referred to as “MN 4” as appropriate), and a home agent (communication device) 5.

  The home agent 5 constructs a virtual network segment 6 inside the communication network 1, that is, functions as a virtual router.

  Therefore, it appears that an external network device or PC terminal has a network of 192.168.30.0/24.

  By consolidating the MN 4 in this virtual network, all packets addressed to the MN 4 pass through the home agent 5. Accordingly, the home agent 5 can receive the packet by proxy.

  As described above, since the virtual network segment 6 is a virtual existence that does not exist, the actual connection relationship of the communication network 1 is as shown in FIG.

  Next, a process for connecting the MN 4 to the external link 8 (192.168.20.0/24) will be described with reference to FIG.

  Note that the packet flow on the external link side is only the transmission / reception of Registration Request / Reply and IPinIP packets, which is the same as the conventional technique shown in FIG.

  On the other hand, the operation on the home side is different from the conventional technique. First, the state of the routing table in the home link 7 is set to a state in which communication with the virtual network link 9 (virtual network segment 6 in FIG. 1) is possible.

  If the network routing format is static routing, an entry addressed to the virtual network link 9 is created in the routing table of the network device.

  On the other hand, when the routing format is dynamic routing, the home agent 5 is accommodated by incorporating a routing protocol function such as RIP (Routing Information Protocol) or OSPF (Open Shortest Path First).

  By constructing the routing as described above, all the packets addressed to the MN 4 having the IP address of the virtual network segment 6 reach the home agent 5.

  The operation after the home agent 5 receives the packet is the same as that of the prior art in FIG. 16, and communication is possible by transferring the packet to the MN 4 of the external link 8 by IPinIP.

  Next, processing when connecting the MN 4 to the home link 7 (192.168.10.0/24) will be described with reference to FIG.

  First, the routing state in the home link 7 is set to a state where communication with the virtual network link 9 is possible.

  If a static route is used in this network, each routing is set manually.

  On the other hand, when dynamic routing is used, the home agent 5 is made to operate as a virtual router by incorporating a function of a routing protocol such as RIP or OSPF.

  Therefore, all packets addressed to the MN 4 having the IP of the virtual network segment 6 are delivered via the home agent 5.

  However, since the IP address of MN4 is different from the home link, communication cannot be performed directly with other terminals, and communication is performed in the same manner as in the FA mode. The procedure at this time is as follows.

  First, Agent Solicitation and Agent Advertisement are sent and received. At this time, the MN 4 holds the MAC address of the home agent 5.

  Next, the home notification is completed by sending and receiving Registration Request and Registration Reply. That is, even when the MN 4 is in the home link 7, the movement registration is performed by the same procedure as in the movement state. At this time, the home agent 5 holds the MAC address of the MN 4.

  When the movement registration of the MN 4 is completed, the communication from the CN 2 to the MN 4 is performed via the virtual router (home agent 5). Therefore, the home agent 5 intercepts the communication packet and transfers it to the MN 4.

  However, since the network address is different between the MN 4 and the home link 7 and the MAC address cannot be resolved by the ARP, the MAC address is directly designated by using the above-mentioned holding information, and communication is performed thereby. Further, when the MN 4 moves in the FA mode, the packet is encapsulated. However, when the MN 4 and the home agent 5 exist in the same segment as illustrated, the encapsulation is not performed.

  Next, the configuration of the home agent 5 will be described with reference to FIG.

  This home agent 5 includes an IP output unit 53 and an IP input unit 54 that control the functions of the transport layer 51 and the IP layer 52 in an OSI (Open Systems Interconnection) reference model, and authentication terminal information that controls the functions of the Mobile IP layer 55. Storage unit 56, routing protocol processing unit 57, home terminal (CN) registration information storage unit 58, mobile terminal registration information table 59, MIP output determination unit 60, MIP processing unit 61 and MIP input determination unit 62, and network IF (Interface) ) It comprises an IF output unit 64 and an IF input unit 65 that control the function of the layer 63.

  The authentication terminal information storage unit 56 stores Mobile IP SPI, an authentication key, and the like, and authenticates the terminal when a Registration Request is transmitted from the MN 4.

  The home terminal registration table storage unit 58 stores a home terminal registration table that is dynamically generated. In this table, the home terminal, that is, CN2 or MN4 that has been successfully registered for movement (has moved to the home link 7). The IP address and MAC address of MN4) are stored in pairs. In addition, when the movement registration performed regularly is not performed even if predetermined time (LiefTime) passes, it is deleted from an entry.

  The mobile terminal registration table storage unit 59 stores a mobile terminal registration table that is dynamically generated. In this table, the IP address and Care- of the MN4 (MN4 that has moved to the external link) that has succeeded in the mobile registration are stored. of-Addres is stored in pairs. In addition, when the movement registration performed regularly is not performed even if predetermined time (LiefTime) passes, it is deleted from an entry.

  The IF output unit 64 transmits the input data to the network.

  The IF input unit 65 transmits the input data to the MIP input determination unit 62.

  The IP output unit 53 performs IP protocol processing on the input data and transmits the data to the MIP output determination unit 60.

  The IP input unit 54 performs IP protocol processing on the input data and transmits it to the transport layer.

  The routing protocol processing unit 57 transmits a packet of a routing protocol such as RIP or OSPF to the IF output unit 64 when the dynamic routing is an effective environment.

  The above packet is for notifying the IF output unit 64 of the network information of its own virtual network link 9, whereby the home agent 5 appears to be a virtual router from the external network. . Note that this process is independent of the MIP process and only performs each routing protocol. The details will be described below with reference to FIG.

  First, it is confirmed whether the routing format is dynamic routing (S61). If this is not dynamic routing (S61: NO), the subsequent processing is not performed (S67).

  On the other hand, if the routing format is dynamic routing (S61: YES), it is confirmed whether OSPF is used (S62), and if OSPF is used (S62: YES), OSPF processing is performed (S62: YES). S64).

  If OSPF is not used (S62: NO), it is confirmed whether RIP is used (S63). If RIP is used (S63: YES), RIP processing is performed.

  Further, when the RIP is not used (S63: NO), the subsequent processing is not performed.

  The MIP input determination unit 62 determines whether the received packet is an Agent Solicitation, Registration Request, ARP Request packet, a packet addressed to the moving MN 4, or a packet addressed to the MN 4 of the home link 7. Note that Agent Solicitation and packets addressed to the moving MN 4 are determined by the same method as in the prior art. If the received packet does not correspond to any of the above packets, the packet is transmitted to the IP input unit 54. Hereinafter, the details will be described with reference to FIG.

  First, it is confirmed whether the packet is Agent Solicitation (S71). If it is Agent Solicitation (S71: YES), the packet is transmitted to the MIP processing unit 61 (S76).

  When the packet is not Agent Solicitation (S71: NO) and is a Registration Request (S72: YES), the packet is transmitted to the MIP processing unit 61 (S76).

  If the packet is not a Registration Request (S72: NO) and the ARP Request is addressed to MN4 (S73: YES), the packet is transmitted to the MIP processing unit 61 (S76).

  If the ARP Request is not addressed to MN4 (S73: NO) and the packet is addressed to the moving MN4 (S74: YES), the packet is transmitted to the MIP processing unit 61 (S76).

  If the packet is not addressed to the moving MN 4 (S74: NO) but is addressed to the MN 4 in the home link 7 (S75: YES), the packet is transmitted to the MIP processing unit 61 (S76).

When the packet is not addressed to the MN 4 on the home link 7 (S75: NO), the packet is transmitted to the IP input unit 54.

  The MIP output determination unit 60 determines whether the received packet is a packet addressed to the moving MN 4 or a packet addressed to the MN 4 of the home link 7. Note that the packet addressed to the moving MN 4 is determined by the same method as in the prior art. If the received packet does not correspond to any of the above packets, the packet is transmitted to the IF output unit 64. Hereinafter, the details will be described with reference to FIG.

  First, it is confirmed whether there is a packet addressed to the moving MN 4 (S81). If the IP packet is addressed to the moving MN 4 (S81: YES), the packet is transmitted to the MIP processing unit 61 (S83).

  On the other hand, if the destination is not the moving MN 4 (S81: NO), it is confirmed whether the destination is the MN 4 on the home link 7 (S82), and if the destination is the MN 4 on the home link 7 (S82: YES) ) Is transmitted to the MIP processing unit 61 (S83).

  If the destination is not the MN 4 in the home link 7 (S82: NO), the packet is transmitted to the IF output unit 64 (S84).

  The MIP processing unit 61 performs processing on the corresponding packet in the processing of the MIP input determination unit 62 and the MIP output determination unit 60.

  In the prior art, when performing the movement registration, the movement registration information from the movement destination is stored in the mobile terminal registration table. In the present invention, as described above, the movement of the MN 4 newly in the home link 7 is stored. A registration table (home terminal) is provided for registration.

  In this case, when the movement registration from the home link 7 is successful, an entry in which the MAC address and the IP address of the MN 4 to be the movement registration are paired is stored in the registration table. In addition, it is assumed that the mobile link is also periodically registered at the half of LifeTime at the home link 7. The details will be described below with reference to FIG.

  First, it is confirmed whether or not the movement registration has failed (S91). If it has failed (S81: YES), the packet is transmitted to the IP input unit 54 (S94).

  On the other hand, if the authentication is successful (not failed) (S91: NO), it is confirmed whether the Registration Request is from the MN4 on the home link 7 (S92), and from the MN4 on the home link 7 (S92: YES), it is registered in the home terminal registration table (S95).

  Further, if the Registration Request is not from the MN 4 on the home link 7 (S92: NO), it is confirmed whether it is from the moving MN 4 (S93), and is from the moving MN 4 (S93: YES) is registered in the mobile terminal registration table (S96).

  On the other hand, when the Registration Request is not from the moving MN 4 (S93: NO), the packet is transmitted to the IP input unit 54 (S97).

  In the prior art, the home agent 105 proxy-receives the ARP Request addressed to the mobile terminal (MN) 103 and issues the ARP Reply as a proxy to proxy-receive the packet addressed to the mobile terminal 103. In the present invention, as described above, a packet addressed to a terminal in the home link 7 can be obtained by issuing an ARP Peply (proxy ARP) on behalf of the home agent in response to an ARP Request addressed to a terminal in the home link 7. Is received by proxy. The details will be described below with reference to FIG.

  First, it is confirmed whether the destination of the ARP Request is a terminal registered in the home terminal registration table (S101), and if it is a registered terminal (S101: YES), a proxy ARP is issued (S103). .

  On the other hand, if the terminal is not registered in the home terminal registration table (S101: NO), it is confirmed whether it is registered in the mobile terminal registration table (S102). If it is registered (S102: YES), the proxy ARP is It is issued (S104).

  When the terminal is not registered (S102: NO), the packet is transmitted to the IP input unit 54.

  In the conventional technique, the packet addressed to the MN 103 on the home link 107 is directly transmitted / received to / from the CN 102 or the home agent 105 (the MN 103 normally operates as a terminal). However, in the present invention, As described above, a packet addressed to the MN 4 on the home link 7 is transmitted / received via the home agent 5.

  When the home agent 5 receives the packet from the CN 2 by proxy, the destination MAC address is rewritten to the MAC address held in the home terminal registration table and transferred to the MN 4.

  Also, the home agent 5 relays the packet transmitted from the MN 4 to the CN 2 and transfers it to the CN 2. The details will be described below with reference to FIG.

  First, an entry corresponding to the IP address is searched from the home terminal registration table (S111), a MAC address is acquired from the searched entry (S112), and rewriting to this address is performed (S113). When the rewriting is completed, the packet is transmitted to the IF output unit 64.

  Next, details of processing in the home agent 5 will be described with reference to FIGS. In the following description, the process shown in FIG. 4 is performed as an example, but the process related to the routing protocol is an independent process, and only the process specified in this is performed. The description is omitted.

  FIG. 12 is a diagram illustrating processing from Agent Solicitation to Registration Reply.

  First, when Agent Solication is received (A in the figure), the MIP processing unit 61 generates an Agent Advertisement, and the IF output unit 64 transmits the generated Agent Advertisement to the network (B).

  Next, when a Registration Request is received from the MN (C). The MIP processing unit 61 performs authentication using the information stored in the authentication terminal information storage unit 56 (D).

  When the authentication is normally performed, an entry is generated in the table stored in the home terminal registration table storage unit 58 (E).

  Thereafter, a Registration Reply is generated, and the IF output unit 64 transmits the generated Registration Reply to the network (F).

  FIG. 13 is a diagram illustrating processing related to the ARP packet.

  First, when an ARP Request packet is received (G), the MIP processing unit refers to the information stored in the home terminal registration table storage unit 58 and the information stored in the mobile terminal registration table storage unit 59 (H and I).

Note that since the registration information of the MN 4 is stored in the above registration table, the information of the home agent 5 is not stored, so the packet is passed to the IP input unit 54. Thereafter, the ARP Reply issued from the IP output unit 53 is transmitted to the IF output unit 64 via the MIP output determination unit 60 (J).
FIG. 14 is a diagram illustrating a process when a PING from CN2 to MN4 is received by proxy.

  First, when the ICMP packet is received by proxy (K), the MIP processing unit receives information stored in the home terminal registration table storage unit 58, information stored in the mobile terminal registration table storage unit 59, and the Destination Address of the IP header. Refer to

  In this example, since the MN 4 is in the home link 7, the corresponding MAC address is acquired from the home terminal registration table storage unit 58 (L). Thereafter, the Destination Address of the header is rewritten and transmitted to the network via the IF output unit 64 (M).

  FIG. 15 is a diagram illustrating processing when a PING response from the MN 4 to the CN 2 is received by proxy.

  First, the ICMP packet is received by proxy (K). As described above, since this packet is not addressed to MN 4, the type cannot be specified by the processing of the MIP input determination unit 62. Therefore, this packet is transmitted to the IP input unit 54.

  A packet received by the IP input unit is transmitted to the actual CN 2 with the destination MAC address changed based on the routing table and ARP of the IP layer 52 and transmitted by the IF output unit 64 (M).

  Note that a communication method using the home agent (communication device) as described above is also included in the scope of the present invention.

  As described above, in the present invention, a home agent as a virtual router is newly added and the mobile terminal device is arranged on the virtual network, so that the home agent is addressed to the mobile terminal device without the need for data link camouflage. Can be received by proxy.

  In addition, the above-described time lag and bandwidth waste due to gratuitous ARP can be suppressed.

  Further, by directly designating the MAC address, communication is possible between networks having different network addresses.

  Further, since packets always pass through the home agent, a VPN (Virtual Private Network) can always be established between the mobile terminal device and the home agent by using IPsec. This is also useful for encryption in a wireless local area network (LAN).

It is a conceptual diagram of the communication network which concerns on one Example of this invention. It is a block diagram of a communication network. It is a figure which shows the process at the time of connecting a mobile terminal device to an external link. It is a figure which shows the process at the time of connecting a mobile terminal device to a home link. It is a block diagram of a home agent. It is a flowchart of a routing protocol process part. It is a flowchart of a MIP input determination part. It is a flowchart of a MIP output determination part. It is a flowchart of a MIP processing part. It is a flowchart of a MIP processing part. It is a flowchart of a MIP processing part. It is a figure which shows the process in a home agent. It is a figure which shows the process in a home agent. It is a figure which shows the process in a home agent. It is a figure which shows the process in a home agent. It is a figure which shows the process in the conventional communication network. It is a figure which shows the process in the conventional communication network. It is a figure which shows the structure of an ARP table. It is a figure which shows the process in the conventional communication network. It is a figure which shows the problem in the conventional communication network.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Communication network, 2 ... Communication terminal device, 3 ... Router, 4 ... Mobile terminal device, 5 ... Home agent, 6 ... Virtual network segment, 7 ... Home link, 8 ... External link,
DESCRIPTION OF SYMBOLS 9 ... Virtual network link, 51 ... Transport layer, 52 ... IP layer, 53 ... IP output part, 54 ... IP input part, 55 ... Mobile IP layer, 56 ... Terminal information storage part for authentication, 57 ... Routing protocol process part 58 ... Home terminal registration table storage unit, 59 ... Mobile terminal registration table storage unit, 60 ... MIP output determination unit, 61 ... MIP processing unit, 62 ... MIP input determination unit, 63 ... Network IF layer, 64 ... IF output unit , 65 ... IF input unit, 101 ... conventional communication network, 102 ... communication terminal apparatus in the conventional example, 103 ... mobile terminal apparatus in the conventional example, 104 ... router in the conventional example, 105 ... home agent in the conventional example, 106 ... conventional Foreign agent in example 107: Home link in conventional example 108: In conventional example External link

Claims (1)

A registration request receiving step of receiving a registration request from a mobile terminal device existing in the same segment as the home agent;
A correspondence construction step of associating the IP address and MAC address of the mobile terminal device based on the registration request;
And a communication step of directly communicating with the mobile terminal device using the MAC address.

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