JP2006114946A - Mobile network system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile network system for optimizing load distribution of a home agent and routing with a communication opposite party. <P>SOLUTION: A plurality of home agent (HA) proxy units 104 each having a home agent function are arranged in a mobile IP network. A mobile router 102 searches and registers an optimum HA proxy unit 104 for each communication opposite party 106 and utilizes the HA proxy unit 104 as an end of a tunnel. In this case, the mobile router 102 searches an address of the HA proxy unit 104 near the communication opposite party 106. The mobile router 102 utilizes (a) a method of extending a home agent address discovery being an HA address searching mechanism, (b) a method wherein the home agent, the communication opposite party, or an HA proxy unit address management server manages addresses of the HA proxy units and resolves the address in response to an inquiry from the mobile router 102, or (c) a method of using a hop by hop option being an extended option of the IPv6 or the like for the searching and the mobile router 102 acquires the address of the HA proxy unit 104. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a mobile network system, and more particularly to a mobile network system for distributing load of a home agent in a communication system using mobile IP and optimizing a route of a mobile terminal and a mobile router.

In the Network Mobility (NEMO) Basic Support Protocol being studied by the IETF, as shown in Non-Patent Document 1, when a terminal connected to a mobile network transmits an IP packet to a communication partner connected to the Internet, the mobile The router encapsulates and transmits to the home agent arranged in the home network of the mobile router. The home agent performs decapsulation and transmits it to the communication partner. As a result, IP packets can be transmitted and received between a terminal connected to the mobile network and an arbitrary communication partner.
Further, as a route optimization method for mobile IP, Non-Patent Document 2 discloses a method for arranging MBG (Mobile IP Border Gateway) at the boundary between a mobile IP network and another IP network. In this method, when the MBG receives a packet from another IP network, the location information of the mobile terminal is acquired in cooperation with the home agent, encapsulated by the MBG, and route optimization to the mobile terminal is performed.
Mobile IP is a technique for transferring a communication packet to a destination when a terminal moves between networks on an IP network, for example, and is described in Non-Patent Document 3, for example.
Network Mobility (NEMO) Basic Support Protocol, Vijay Devapalli, draft-ietf-nemo-basic-support-03. txt, June / 2004 "Route optimization method in Mobile IPv6 network", Hiroyuki Onishi, IEICE Technical Report, December 2000 RFC3775, Mobility Support in IPv6, June, 2004

In NEMO, communication from a terminal connected to a mobile network to a communication partner generally passes through a home agent arranged on the home link of the mobile router. Therefore, the communication path between the terminal connected to the mobile network and the communication partner is a triangular path. For example, even when a terminal and a communication partner communicate with each other at a short distance, the route on the network may become unnecessarily long, such as communication via a remote home agent. In addition, load concentration on the home agent is an issue.
In the method of arranging the MBG, the MBG is arranged at the boundary of the mobile IP network, and the route of the packet received from the other IP network is optimized. Therefore, route optimization from the mobile IP network to the other IP network cannot be performed, and the MBG is arranged at the boundary between the mobile IP network and the other IP network, so that load concentration on the MBG becomes a problem.
In view of the above points, an object of the present invention is to distribute the load of a home agent.
Another object of the present invention is to optimize the route of a communication route between a terminal connected to a mobile network and a communication partner. Furthermore, another object of the present invention is to arrange a home agent agent device having a home agent function (hereinafter referred to as an HA agent device) near the network of the communication partner, and for the mobile router, an optimum HA agent device for each communication partner. Search and register, and use the HA proxy device as the end of the tunnel. At this time, the object is to search for the address of the HA proxy device near the communication partner.
Another object of the present invention is to reduce a communication delay by optimizing a communication path between a terminal connected to a mobile network and a communication partner. Furthermore, it is an object of the mobile router to be able to use a plurality of interfaces simultaneously by selecting a care-of address to be registered for each HA proxy device.

In order to achieve the above-described object, HA substitution devices are arranged in a plurality of networks, and means for acquiring the address of the HA substitution device near the communication partner is provided. The means for the mobile router to acquire the address of the HA proxy device is a method of extending home agent address discovery, which is an HA address search mechanism, or the HA proxy device address is set by the home agent, the communication partner or the HA proxy device address management server. It is configured by a method of managing and solving by inquiry from the mobile router, or a method of acquiring the address of the HA proxy device using a hop-by-hop option header which is an IPv6 extension option.
According to the solution of the present invention,
A movable first node;
A home agent that is arranged in a home network that is a network to which the first node belongs, and that performs communication processing including encapsulation and decapsulation for communication packets of the first node;
A second node in communication with the first node;
A home agent agent device that is arranged for the second node and performs communication processing including encapsulation and decapsulation for communication packets of the second node;
When the first node moves to another network connected to the home network, during the communication with the second node via the home agent arranged in the home network, in the moved network,
The first node creates and transmits a signal for searching for the home agent agent device, receives a response corresponding to the signal including an address of the home agent agent device, and receives the response according to the signal. Execute the search process to get the address of
The first node communicates with the second node without passing through the home agent via the home agent proxy device according to the second node according to the acquired address. Is provided.

According to the present invention, the load of the home agent can be distributed. Further, according to the present invention, the route of the communication route between the terminal connected to the mobile network and the communication partner can be optimized. Further, according to the present invention, the HA proxy device having the home agent function is arranged near the communication partner network, and the mobile router searches and registers the optimum HA proxy device for each communication partner, and the HA proxy device is used as a tunnel termination. Can be used. At that time, the address of the HA proxy device near the communication partner can be searched.
Further, according to the present invention, it is possible to reduce the communication delay by optimizing the communication path between the terminal connected to the mobile network and the communication partner. Further, the load distribution of home agents can be achieved by using a plurality of HA proxy devices by the mobile router. Furthermore, since the care-of address registered for each HA proxy device can be selected, the mobile router can use a plurality of interfaces simultaneously.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a configuration example of a mobile IP communication system in which the present invention is implemented. The system shown in FIG. 1 includes a home agent (HA) 101 arranged in a home network 111, a mobile router (MR) 102 moving from the home network 111 to the visited network 112, and a mobile network 114. A fixed terminal (LFN, Local Fixed Node) 103 connected to the communication terminal, nodes (CN, Correspondent Node) 105 and 106 of a communication partner of the fixed terminal 103, and an HA proxy device 104 arranged in the network of the communication partner 106. The home network 111, the visited network 112, and the Internet 113 are connected to each other using, for example, the Internet protocol. In the present embodiment, for example, routers and terminals defined in Non-Patent Documents 1 and 3 can be used as mobile routers, fixed terminals, mobile terminals, and the like.
The mobile router 102 moves from the home network 111 to another network 112 and can communicate with other nodes via the home agent 101 even in the moved network. Further, the hardware configuration of the HA proxy device 104 can be the same as that of the home agent 101. In the present embodiment, the mobile router 102 may be a mobile terminal, which may be referred to as a first node. The communication partners 105 and 106 may be mobile terminals or fixed terminals, and these may be referred to as second nodes.
FIG. 30 shows an arrangement example of the HA substitution device 104.
For example, one or more HA proxy devices 104 are arranged in the same network as the communication partner 106, and can communicate with the mobile router 102 or the like via the router 150 (FIG. 30-a). Further, the HA proxy device 104 is disposed between the communication partner 106 and the mobile router 102, and can also include a router function (FIG. 30-b).
FIG. 2A is a configuration example of the mobile router device 102. A CPU (Central Processing Unit) 201 actually executes various application programs and an OS (Operating System). The memory 202 stores programs used in the execution of the CPU 201 and various application programs. The CPU 201 and the memory 202 are connected via a bus 203. The interface units 204, 205, and 206 accommodate the lines 207, 208, and 209 and communicate with other devices. The interface units 204, 205, and 206 output data supplied from the CPU 201 and the memory 202 to an external device, and supply data supplied from an external device to the CPU 201 and the memory 202.
FIG. 2B shows functional blocks of the mobile router 102. The memory 202 has a mobile IP process 211 in addition to the basic OS process 212. In addition, the memory 202 includes an HA proxy device address table 213 and a binding list 214. Furthermore, the memory 202 has an appropriate routing table. For example, the routing table includes a destination address, a transmission source address, a transmission interface, a next hop, and the like.
The basic OS process 212 includes a packet transmission / reception process 220 that performs an IP packet transmission / reception process, and a tunnel / routing header process 219 that performs an IP packet encapsulation or decapsulation process.
The mobile IP processing 211 includes a mobile IP message processing 218 for processing a mobile IP message such as a binding update, a movement detection processing 217 for detecting movement of the mobile network 114, and an HA proxy device corresponding to each of the communication partners 105 and 106. HA proxy device address search processing 216 for searching for an address, and registered CoA selection processing 215 for selecting a CoA (care of address, care-of address) to be registered when performing a binding update to the HA and the HA proxy device. Here, the CoA is, for example, an address for identifying the destination network of the mobile router 102.
The mobile IP message processing 218 processes mobile IP messages such as a binding update message, a binding acknowledgment (hereinafter referred to as a binding acknowledgment), a binding error, and the like.

The movement detection process 217 analyzes router advertisements (Router Advertisements) advertised in the network to which the mobile terminal or router currently belongs. For each IF, it is compared whether the network prefix of the currently received router advertisement matches the network prefix of the previously received router advertisement, and determines whether the mobile terminal has moved through the network. For example, it can be determined that there is no movement when the network prefixes match, and it can be determined that the network prefixes move when they do not match. If a router advertisement is not received from the IF for a certain period of time, it is determined that the IF is disconnected.
The search result of the HA proxy device address search process 216 is managed by the HA proxy device address table 213. FIG. 3A shows an example of the HA proxy device address table. The HA proxy device address table 213 represents the correspondence relationship between the address of the communication partner or the prefix 301 and the HA proxy device address 304. In addition, when the counter 302 stores the number of packets transmitted from the fixed terminal 103 to the communication partner, the HA proxy device address search state 303 exists, and a plurality of HA proxy devices 104 exist for one communication partner. It has a priority 305 indicating which HA proxy device 104 has priority. The state 303 includes, for example, a searched flag and an authentication failure flag.
The binding update destination is managed by the binding list 214. An example of the binding list is shown in FIG. The binding list 214 includes a binding update transmission destination address (HA proxy device 104 address) 306, a care-of address 308 registered by the mobile router, and a tunnel interface 307. The tunnel interface 307 is an appropriate identifier for identifying the entrance of the tunnel with the HA proxy device 104.

FIG. 4 shows a processing flow of HA proxy device address search processing. When the mobile router 102 receives a packet addressed to the communication partner from the fixed terminal 103 (step 401), it searches the HA proxy device address table 213 (step 402). The mobile router 102 determines whether an entry of the communication partner exists in the HA proxy device address table 213 (step 403), and if not, newly adds an entry (step 404). For example, the mobile router 102 stores the destination address of the received packet in the CN address column 301 of the HA proxy device address table 213 as a new entry. The mobile router 102 increments the counter 302 of the entry (for example, increments by 1) (step 405), and determines whether the number of counters exceeds the threshold and has been searched (step 406). The threshold value is predetermined and can be stored in the memory 202 or the like. Whether the search has been completed can be determined by referring to the searched flag in the state 303. If the number of counters exceeds the threshold value and the search has not been performed, the mobile router 102 performs HA proxy device search processing (step 407) and HA proxy device registration processing (step 408). On the other hand, in other cases, the mobile router 102 ends the HA proxy device address search process.
FIG. 5 shows a processing flow of HA proxy device search processing (step 407). The mobile router 102 takes the upper 64 bits from the destination address of the packet received from the fixed terminal 103, and creates an address by assigning the anycast address reserved for the home agent to the lower 64 bits (step 501). The mobile router 102 creates a home agent address discovery request using the address created in step 501 as a destination address. At this time, the C bit representing the request for the HA proxy device address is set and the request is transmitted (step 502). The request destination address uses the upper bits (for example, CN prefix) of the packet destination address as shown in step 501, and is delivered to the HA proxy device 104 in the network of the communication partner 106.

When the HA agent device 104 receives the home agent address discovery request, it confirms that the C bit is set and creates a home agent address discovery reply. In addition, the C bit is set in the reply.
Note that the HA proxy devices belonging to the same link hold the address list including the addresses of the HA proxy devices belonging to the link by receiving mutual router advertisements. The search request message transmitted from the mobile node 102 and destined for the address created by the prefix 64 bits of the communication partner 106 and the anycast address 64 bits allocated for the home agent is sent to any of the plurality of HA proxy devices 104. The home agent address discovery reply including the address list received and held by the HA proxy device 104 is returned to the mobile router 102. As a result, the mobile router 102 is notified of the address of the HA proxy device 104 on the link of the communication partner 106.
When receiving the home agent address discovery reply (step 503), the mobile router 102 checks the presence or absence of the C bit representing the address of the HA proxy device 104 (step 504). If the C bit is set, the HA proxy that can be registered is confirmed. The device 104 is determined (step 505). In addition, the mobile router 102 stores the address of the HA proxy device included in the home agent address discovery reply at an appropriate timing in the HA proxy device address table 213 in association with the corresponding CN address.
On the other hand, if the home agent address discovery reply is not received within a predetermined time, or if the C bit of the received home agent address discovery reply is not set, it is determined that there is no HA proxy device that optimizes the route to the communication partner ( Step 506). Note that the mobile router 102 can appropriately store the determination results of steps 505 and 506.

FIG. 6 shows a process flow of the HA substitution apparatus registration process (step 408). The mobile router 102 determines whether there is a HA proxy device that can be registered (step 601). If it is determined that there is no HA proxy device, the mobile router 102 sets a searched flag in the state 303 and ends the processing (step 609). The mobile router 102 can determine whether there is a HA proxy device 104 that can be registered by referring to the determination results stored in the above-described steps 505 and 506.
When the mobile router 102 determines that there is a HA proxy device that can be registered (step 601), the HA proxy device 104 and the mobile router 102 authenticate each other (step 602). Here, when the mobile router 102 acquires the addresses of a plurality of HA proxy devices 104, one HA proxy device is provided according to a predetermined rule (for example, one with a high priority, one close to a communication partner, etc.). An address can be selected, and authentication can be performed with the HA proxy device 104 corresponding to the selected address. If the authentication fails (step 602), the mobile router 102 sets an authentication failure flag (step 608) in the state 303, sets a searched flag (step 609), and ends the process. On the other hand, if the authentication is successful (step 603), a care-of address registered in the HA proxy device 104 is selected (step 604), and binding update processing is performed on the HA proxy device (step 605).
In selecting the care-of address, for example, when the mobile router 102 is connected to a plurality of networks, there is a CoA for each network, and the mobile router 102 can select an appropriate one from the plurality of CoAs. Note that any CoA can be selected by using an appropriate method such as selecting one predetermined or selecting according to traffic. Further, CoA changes when the network connected by the movement of the mobile router 102 changes, but CoA (CoA ₁ ) corresponding to the previously connected network and CoA (CoA corresponding to the currently connected network). _{For example} , when both of ₂ ) are stored in the mobile router 102, CoA ₂ can be selected.

In the binding update process (step 605), a tunnel interface is created with the selected care-of address as the start point and the HA proxy device address as the end point. By the binding update process, the selected CoA is notified to the HA proxy device. When the binding update process is completed, the mobile router 102 has a new address in the routing table of the mobile router 102, the destination address is the address (or prefix) of the communication partner, the source address is the prefix of the mobile network 114, and the transmission interface is An entry to be a tunnel interface created between the HA proxy device 104 and the mobile router 102 is added (step 606).
Next, the mobile router 102 registers the HA proxy device address 306, the registered care-of address 308, and the tunnel interface name 307 in the binding list 214 (step 607), and sets the searched flag in the state 303 of the HA proxy device address table 213. The standing is finished (step 609).

FIG. 7 shows a communication sequence when the route from the fixed terminal 103 to the communication partners 105 and 106 is optimized by the route optimization method of the mobile router according to the present embodiment. Here, the communication sequence will be described with reference to FIG. 1 and FIG.
The mobile router 102 detects that it has moved to the visited network 112 and transmits a binding update to the home agent 101. The home agent 101 registers in the binding cache and transmits a binding ack to the mobile router 102. A bidirectional tunnel is established between the mobile router 102 and the home agent 101, and communication between the fixed terminal 103 and the communication partner 106 passes through this bidirectional tunnel (for example, the route of the packets 121, 122, and 123 in FIG. 1). .
When the number of packets transmitted to the communication partner 106 exceeds the threshold value, the HA proxy device address search process shown in step 407 of FIG. 4 is performed. In the address search process, the number of packets from the fixed terminal 106 exceeds the threshold when the number of packets processed by the home agent 101 exceeds the threshold, except when the number of packets transmitted to the communication partner exceeds the threshold. It may be executed in some cases, and is not limited thereto, and may be an appropriate condition. Alternatively, the HA proxy device 104 may be searched from the beginning without performing communication via the home agent 101, and communication via the HA proxy device 104 may be performed.
An example of the format of the home agent address discovery request transmitted from the mobile router 102 at this time is shown in FIG. An R bit indicating that the router is a mobile router and a C bit indicating a request of the HA proxy device are set in the flag. Note that the address created in Step 501 is used as the destination address (Destination Address).

In response to the home agent address discovery request, the HA proxy device returns a home agent address discovery reply shown in FIG. 9 to the mobile router. In the present embodiment, the address of the HA substitution device 104 is included in the fields Home Agent Address 1, 2,...
Returning to FIG. 7, when the mobile router 102 acquires the address of the HA proxy device 104 (when receiving the home agent address discovery reply), authentication processing is performed between the mobile router 102 and the HA proxy device 104 corresponding to the acquired address. . Conventional authentication techniques can be applied for authentication. If the authentication is successful, the mobile router 102 selects a registered CoA, performs a binding update to the HA proxy device 104, and creates a tunnel between the mobile router 102 and the HA proxy device 104. When the mobile router receives the packet to the communication partner 106, it encapsulates it in the HA proxy device and optimizes the route.
In the subsequent communication, when the mobile router 102 receives a packet addressed to the communication partner 106 from the fixed terminal 103, the mobile router 102 obtains the next hop and the transmission interface by subtracting the routing table from the destination address and the source address of the received packet. If the packet is addressed to the communication partner 106, the mobile router 102 transmits the packet to the tunnel interface created between the mobile router 102 and the HA proxy device 104 according to the transmission interface obtained from the routing table.

In the tunnel interface, encapsulation is performed with an IP packet whose destination address is the address of the HA proxy device 104 and whose transmission source address is the registered CoA of the mobile router 102. Here, the address of the HA proxy device 104 is determined by referring to the HA proxy device address table 213 based on the destination address (address or prefix of the communication partner 106) of the packet transmitted by the mobile router 102, for example. The address corresponding to can be obtained. As for the registered CoA, for example, the mobile router 102 can obtain the registered CoA corresponding to the tunnel interface or the HA proxy device address by referring to the binding list 214. In addition, the address of the HA substitution device 104 and the registered CoA can be obtained from an appropriate table or the like stored in the memory.
The newly created IP packet is transmitted to the visited network 112 according to the routing table. When the HA proxy device 104 receives the encapsulated packet, it performs decapsulation and transfers the packet to the communication partner 106 according to the destination address (routes of packets 124, 125, and 126 in FIG. 1).
Here, a case where there is no HA proxy device in the vicinity of the communication partner 105 will be described. Even when the mobile terminal 102 transmits a home agent address discovery request during data communication between the fixed terminal 103 and the communication partner 105 via the HA, the mobile router 102 receives a home agent address discovery reply message from the HA proxy device 104. Not reach. In this case, the search fails, and the fixed terminal 103 and the communication partner 105 continue data communication via the HA 101 as before.
Here, a case where the mobile router 102 moves will be described.
FIG. 29 shows a processing flow when the mobile router 102 moves. The mobile router 102 receives the router advertisement (step 311) and detects network movement (step 312). For example, the mobile router 102 can detect the movement of the network by detecting prefix information different from that of the network before the movement. Next, the mobile router 102 refers to the binding list (step 313). The mobile router 102 specifies from the binding list 214 the HA proxy device that needs to be registered and updated due to the change of the care-of address (step 314). For example, the mobile router 102 refers to the registered CoA 305 in the binding list 214 based on the care-of address generated by the router advertisement, and acquires the HA proxy device address of the entry whose care-of address does not match the registered CoA. The mobile router 102 transmits a binding update to the HA proxy device 104 according to the selected HA proxy device address (step 315). Further, the mobile router 102 stores the care-of address in, for example, the registered CoA corresponding to the HA proxy device address that transmitted the binding update.

In the first embodiment described above, a method for performing the HA proxy device address search by the home agent 101 shown in FIG. 1 will be described. The overall configuration of the mobile IP communication system and the configuration of the mobile router 102 are the same as those in the first embodiment.
10A and 10B are configuration examples of the home agent 101 used in this embodiment. The home agent 101 includes a CPU 1001, a memory 1002, and interfaces 1004 and 1005. These are connected by a bus 1003. The functions added to the conventional home agent are, for example, holding of the HA proxy device management table 1013 and HA proxy device address management processing 1015. The HA proxy device address management process will be described in detail later.
The binding cache table 1014 holds a correspondence relationship between at least the home address of the mobile router 102, the prefix of the mobile network 114, and the care-of address. The binding management processing 1016 manages the binding cache table 1014 that holds the correspondence relationship between the care-of address of the mobile router 102, the home address, and the prefix of the mobile network. The mobile IP message processing 1018 processes a mobile IP message such as a binding update message, a binding acknowledgment, or a binding error. The tunnel processing 1019 performs IP packet encapsulation and decapsulation processing. The packet transmission / reception processing 1020 performs IP packet transmission / reception processing.
FIG. 11 shows an example of the HA substitution device management table 1013. The HA substitution device management table 1013 holds the correspondence between the CN address or prefix 1101 and the HA substitution device address 1102. Further, when there are a plurality of HA proxy device addresses for CN, it has a priority 1103 for determining the HA proxy device to be registered.
The mobile router 102 executes HA proxy device address search processing. For example, each process shown in FIG. 4 is executed. Note that the details of steps 401 to 406 and 408 are the same as described above, and will be omitted. In the present embodiment, the HA proxy device search process in step 407 executes the following process.

FIG. 12A shows a processing flow of the HA proxy device search processing (step 407) of the mobile router 102. An HA proxy device address inquiry message is transmitted from the mobile router 102 to the home agent 101 (step 1201). The message includes, for example, the address or prefix of the communication partner. When the mobile router 102 receives a response message including the HA proxy device address from the home agent 101 (step 1202), the mobile router 102 determines that there is a registerable HA proxy device (step 1203), and ends the HA proxy device search process. . In addition, when the HA proxy device address response message cannot be received within a predetermined time, or the valid HA proxy device address is not included in the response message, the mobile router 102 performs HA proxy to optimize the route to the corresponding communication partner. It is determined that there is no device (step 1204), and the process ends.
FIG. 12B shows HA proxy device address management processing 1015 in the home agent 101. The home agent 101 receives the HA proxy device address inquiry message from the mobile router 102 (step 1205). The home agent 101 searches the HA proxy device management table based on the address of the communication partner 106 included in the received inquiry message (step 1206). If there is an entry including the address of the corresponding communication partner (step 1207), the home agent 101 acquires the HA proxy device address 1102 corresponding to the address 1101 of the corresponding communication partner, and uses the acquired address as the HA proxy. Included in the device address response message. On the other hand, when there is no entry including the address of the corresponding communication partner (step 1207), the home agent 101 transmits a message indicating that there is no HA proxy device 104 for the corresponding communication partner. Further, for example, a response message including the address of the own HA, a response message not including the address, or the like may be returned.

FIG. 13 shows a processing sequence.
The HA proxy device 104 registers the HA proxy device address with the home agent 101 in advance. For example, the HA agent device 104 transmits the address of the own HA agent device and the address or prefix of the CN (for example, the communication partner 106) managed by the HA agent device to the home agent 101. The home agent 101 receives the HA proxy device address and CN address or prefix, and registers them in the HA proxy device management table 1013.
The mobile router 102 and the home agent 101 perform the transmission / reception of the binding update, the registration to the binding cache, and the transmission / reception of the binding ack as in the first embodiment, and the fixed terminal 103 and the communication partner 106 communicate with each other via the bidirectional tunnel. Communicate.
When a predetermined condition such as the number of transmission packets to the communication partner 106 exceeds a threshold value (or even if the condition is not satisfied), HA proxy device address search processing shown in FIG. 12 is performed. The conditions for starting the address search process may be appropriate conditions as described above. The mobile router 102 transmits and receives the HA proxy device address inquiry message and the response message, and acquires the address of the HA proxy device 104 corresponding to the communication partner 106.
Thereafter, processing such as authentication, binding update, and tunnel creation between the mobile router 102 and the HA proxy device 104 is executed in the same manner as the sequence in FIG. 7 described above, and communication is performed with the communication partner 106 via the created tunnel. .
Here, communication to a communication partner that does not have the corresponding HA proxy device 104 will be described. Even if the mobile terminal 102 transmits the HA proxy device address inquiry message while the fixed terminal 103 and the communication partner 105 are performing data communication via the HA 101, the corresponding HA proxy device address is not registered in the home agent 101. Therefore, for example, a response message including the address of the HA or a response message not including the address is returned. In this case, the fixed terminal 103 and the communication partner 105 continue data communication via the HA 101.
FIG. 14 shows an example of an inquiry message from the mobile router 102 to the home agent 101. The inquiry message includes the address (CN address) of the communication partner. FIG. 15 shows an example of a response message from the home agent 101 to the mobile router 102. The response message includes one or more HA proxy device addresses.
Other processes are the same as those in the first embodiment.

In the first embodiment described above, a method for performing the HA proxy device address search at the communication partner 106 shown in FIG. 1 will be described. This is an embodiment in which the search method performed in the second embodiment is changed from the home agent 101 to the communication partner 106, and will be described below. The overall configuration of the mobile IP communication system and the configuration of the mobile router 102 are the same as those in the first embodiment.
FIG. 16A is a configuration example of the communication partner (node) 106 used in this embodiment. The communication partner node includes, for example, a CPU 1601, a memory 1602, and an interface 1604. These are connected by a bus 1603. The functions added to the communication partner 106 in the first embodiment are holding the HA proxy device management table 1613 and HA proxy device address management processing 1614. The HA substitution device management table 1613 can be the same as that shown in FIG. The CN address or prefix may be omitted. The packet transmission / reception processing 1616 is the same as the processing 1020 in the home agent 101 of the second embodiment described above.
The mobile router 102 executes HA proxy device address search processing. For example, each process shown in FIG. 4 is executed. Note that the details of steps 401 to 406 and 408 are the same as described above, and will be omitted. In the present embodiment, the HA proxy device search process in step 407 executes the following process.
FIG. 17 shows a processing flow of the HA proxy device search processing (step 407) of the mobile router 102. The mobile router 102 transmits an HA proxy device address inquiry message to the communication partner 106 (step 1701). The message is delivered to the communication partner 106 via the home agent 101, for example. When the mobile router 102 receives a response message including the HA proxy device address from the communication partner 106 (step 1702), the mobile router 102 determines that there is a registerable HA proxy device (step 1703), and ends the HA proxy device search process. . Further, when the HA proxy device address response message cannot be received within a predetermined time, or the valid HA proxy device address is not included in the response message, the mobile router 102 optimizes the route to the corresponding communication partner. It is determined that there is no substitute device (step 1704), and the process ends.

Note that the HA proxy device address management processing 1614 in the communication partner 106 is the same processing as the steps in FIG.
FIG. 18 shows a processing sequence.
The HA proxy device 104 registers the HA proxy device address with the communication partner 106 in advance. For example, the HA proxy device 104 transmits the address of its own HA proxy device to the communication partner 106 managed by the HA proxy device 104. The communication partner 106 receives the address of the HA proxy device, and registers the received address of the HA proxy device and its own address or prefix in the HA proxy device management table 1613.
The mobile router 102 and the home agent 101 create a tunnel in the same manner as described above, and the fixed terminal 103 and the communication partner 106 communicate with each other via the created bidirectional tunnel.
When a predetermined condition such as the number of transmitted packets to the communication partner 106 exceeds (or does not satisfy) a threshold value, the HA proxy device address search process shown in FIG. 17 is performed. The mobile router 102 transmits and receives the HA proxy device address inquiry message and the response message, and acquires the address of the HA proxy device 104 corresponding to the communication partner 106.
Thereafter, similarly to the sequence in FIG. 7 described above, processing such as tunnel creation between the mobile router 102 and the HA proxy device 104 is executed, and the mobile router 102 communicates with the communication partner 106 via the created tunnel. .
Here, communication to a communication partner having no corresponding HA substitution device will be described. Even when the mobile terminal 102 transmits an HA proxy device address inquiry message to the communication partner 105 during data communication between the fixed terminal 103 and the communication partner 105 via the home agent 101, the address of the HA proxy device is sent to the communication partner 105. Is not registered, the HA proxy device address response message is not returned. Alternatively, a response message not including the address of the HA proxy device is returned. In this case, the fixed terminal 103 and the communication partner 105 continue data communication via the home agent 101.
The inquiry message from the mobile router 102 to the communication partner 106 can be the same as that shown in FIG. The response message from the communication partner 106 to the mobile router 102 can be the same as that shown in FIG. The inquiry message may not include the communication partner address (CN address).
Other processes are the same as those in the first embodiment.

In the first embodiment described above, a method of performing the HA proxy device address search by the HA proxy device address management server 107 shown in FIG. 19 will be described. In this embodiment, the search method performed in the second embodiment is changed from the home agent 101 to the HA proxy device address management server 107, which will be described below.
The mobile IP communication system further includes an HA proxy device address management server 107. This server is connected to the Internet, for example.
FIG. 20A is a configuration example of the HA proxy device address management server 107 used in this embodiment. The HA proxy device address management server 107 includes a CPU 2001, a memory 2002, and an interface 2004. These are connected by a bus 2003. The functions that are characteristic of the HA proxy device address management server 107 are, for example, retention of the HA proxy device management table 2013 and HA proxy device address management processing 2014. The HA substitution device management table 2013 can be the same as in FIG.
FIG. 20B shows functional blocks of the HA proxy device address management server 107. The memory 2002 includes an HA proxy device management table 2013, an HA proxy device address management process 2014, a tunnel process 2015, and a packet transmission / reception process 2016. The tunnel process 2015 and the packet transmission / reception process 2016 can be the same as the processes 1019 and 1020 of the home agent 101 shown in FIG.
The mobile router 102 executes HA proxy device address search processing. For example, each process shown in FIG. 4 is executed. Note that the details of steps 401 to 406 and 408 are the same as described above, and will be omitted. In the present embodiment, the HA proxy device search process in step 407 executes the following process.

FIG. 21 shows a processing flow of the HA proxy device search processing (step 407) of the mobile router 102. The mobile router 102 transmits an HA proxy device address inquiry message to the HA proxy device address management server 107 (step 2101). The message includes, for example, the address or prefix of the communication partner. When the mobile router 102 receives a response message including the HA proxy device address from the HA proxy device address management server 107 (step 2102), the mobile router 102 determines that there is a registerable HA proxy device (step 2103), and searches for the HA proxy device. End the process. Further, if the HA proxy device address response message cannot be received within a predetermined time, or if a valid HA proxy device address is not included in the response message, there is no HA proxy device that optimizes the route to the corresponding communication partner. Judgment is made (step 2104) and the process is terminated.
The HA proxy device address management process 2014 in the HA proxy device address management server 107 can be the same as the above-described processes in FIG.
FIG. 22 shows a processing sequence.
The HA proxy device registers the HA proxy device address in advance with the HA proxy device management server. The details of the HA proxy device address registration can be the same as in the second embodiment.
The mobile router 102 and the home agent 101 create a tunnel in the same manner as described above, and the fixed terminal 103 and the communication partner 106 communicate with each other via the created bidirectional tunnel.
When a predetermined condition such as the number of transmitted packets to the communication partner 106 exceeds a threshold value (or does not satisfy the predetermined condition), HA proxy device address search processing shown in FIG. 21 is performed. The mobile router 102 transmits / receives the HA proxy device address inquiry message and the response message, and acquires the address of the HA proxy device 104 corresponding to the communication partner 106 from the HA proxy device address management server 107.

Thereafter, similarly to the sequence in FIG. 7 described above, processing such as tunnel creation between the mobile router 102 and the HA proxy device 104 is executed, and the mobile router 102 communicates with the communication partner 106 via the created tunnel. .
The communication with the communication partner 105 that does not have the corresponding HA proxy device 104 is the same as that in the second embodiment.
The inquiry message from the mobile router 102 to the HA proxy device address management server 107 can be the same as that shown in FIG. The response message from the HA proxy device address management server 107 to the mobile router 102 can be the same as in FIG.
Other processes are the same as those in the first embodiment.

In the first embodiment described above, a method for performing the HA proxy device address search using the hop-by-hop option header will be described. The overall configuration of the mobile IP communication system and the configuration of the mobile router 102 are the same as those in the first embodiment.
FIG. 23A is a configuration example of the HA substitution device 104 used in this embodiment. The HA proxy device 104 includes a CPU 2301, a memory 2302, and interfaces 2304 and 2305. These are connected by a bus 2303. A function that is a feature of the HA proxy device 104 is, for example, an HA proxy device address notification process 2315. Further, the binding cache table 2314, the binding management process 2316, the mobile IP message process 2318, the tunnel process 2319, and the packet reception process 2320 are the same as the corresponding table and process shown in FIG.
FIG. 24-A is a configuration example of the communication partner 106 used in this embodiment. The communication partner 106 has an HA proxy device address notification process 2414. In addition, the same code | symbol is attached | subjected about the thing similar to the structure shown in FIG. 16, and the description is abbreviate | omitted.
The mobile router 102 executes HA proxy device address search processing. For example, each process shown in FIG. 4 is executed. Note that the details of steps 401 to 406 and 408 are the same as described above, and will be omitted. In the present embodiment, the HA proxy device search process in step 407 executes the following process.
FIG. 25 is a processing flow of HA proxy device search processing (step 407).
FIG. 25A shows a processing flow of HA proxy device search processing (step 407) of the mobile router 102. The mobile router 102 transmits an HA proxy device address search message with a hop-by-hop option header added to the communication partner 106 (step 2501).
The mobile router 102 receives the response message from the communication partner 106 (step 2502), and if the HA proxy device address is included in the response message (step 2503), the mobile router 102 determines that there is a registerable HA proxy device. (Step 2504), the HA substitution device search process is terminated. Also, if the HA proxy device address response message cannot be received within a predetermined time, or if a valid HA proxy device address is not included in the response message, there is no HA proxy device that optimizes the route to the corresponding communication partner. Judgment is made (step 2505) and the process is terminated.

FIG. 25B shows HA proxy device address notification processing 2401 in the communication partner 106. Upon receiving the HA proxy device address search message from the mobile router 102, the communication partner 106 transmits a response message with the hop-by-hop option added to the mobile router 102.
FIG. 25C shows the HA proxy device address notification process 2315 in the HA proxy device 104. The HA proxy device 104 receives the packet with the hop-by-hop option header added (step 2521), and if the option type (Option Type) is the HA proxy device address search option (step 2522), The address of the own node is attached to the data part, and the message is transferred (step 2523). On the other hand, if it is not the HA proxy device address search option, the processing corresponding to the other option is executed and the process is terminated.
Note that the HA substitution device 104 itself also handles packets from the mobile router 102 to which the hop-by-hop option header is added to the communication partner 106 and packets from the communication partner 106 to the mobile router 102. It can be transferred with the node address. Accordingly, the search packet with the hop-by-hop option header added is transmitted from the communication partner 106 to the mobile router 102, and the mobile router 102 receives the forwarded search packet including the address of the home agent proxy device, and receives the home agent proxy. The address of the device can be obtained. Alternatively, a search packet with a hop-by-hop option header added is transmitted from the mobile router 102 to the communication partner 106, and the mobile router 102 receives the forwarded search packet from the communication partner 106 and receives the home agent proxy device in the search packet. It is also possible to receive the signal including the address of the home agent and obtain the address of the home agent agent device.

FIG. 26 shows a processing sequence.
The mobile router 102 and the home agent 101 create a tunnel in the same manner as described above, and the fixed terminal 103 and the communication partner 106 communicate with each other via the created bidirectional tunnel.
When a predetermined condition such as the number of transmitted packets to the communication partner 106 exceeds a threshold value (or does not satisfy the predetermined condition), HA proxy device address search processing shown in FIG. 25 is performed. The mobile router 102 transmits and receives the HA proxy device address inquiry message and the response message to which the hop-by-hop option is added, and acquires the address of the HA proxy device 104 corresponding to the communication partner 106.
Thereafter, similarly to the sequence in FIG. 7 described above, processing such as tunnel creation between the mobile router 102 and the HA proxy device 104 is executed, and the mobile router 102 communicates with the communication partner 106 via the created tunnel. .
Note that the communication to the communication partner 105 that does not have the corresponding HA proxy device 104 is not received by the HA proxy device 104 even if the mobile router 102 transmits an inquiry message. Therefore, the address of the HA proxy device 104 is included in the response message. Not included. In this case, the fixed terminal 103 and the communication partner 106 continue to communicate via the home agent 101.
When a plurality of HA proxy devices 104 exist on the path between the fixed terminal 103 and the communication partner 106, each HA proxy device 104 can sequentially store its own address in the data section. For example, when receiving the HA proxy device address response message, the mobile router 102 is the HA proxy device 104 having the oldest stored address closest to the communication partner 106 among the addresses of the HA proxy devices included in the response message. This address can be registered in the HA proxy device address table 213 and the binding list 214.

FIG. 27 shows an example of an inquiry message from the mobile router 102 to the communication partner 106. FIG. 28 shows an example of a response message from the communication partner 106 to the mobile router 102.
In the figure, the HA proxy device address search option 2701 corresponds to the hop-by-hop option added in steps S2501 and S2512 described above. In the Option type of the HA proxy device address search option 2701, the HA proxy device address search option is set. Further, the address of the HA proxy device is written in the data part of the HA proxy device address search option 2701.
Other processes are the same as those in the first embodiment.

  The present invention can be used to construct a service that provides a communication environment to a mobile terminal. This is particularly effective in a system having a large number of mobile terminals, such as a communication network service for automobiles.

1 is a conceptual diagram of a network to which the present invention is applied. The block diagram which shows the internal structure of the mobile router used by this invention. The conceptual diagram explaining the structure of a HA substitution apparatus address table. The flowchart explaining the route optimization procedure using HA substitution apparatus. 6 is a flowchart for explaining HA proxy device search processing. 6 is a flowchart for explaining HA proxy device registration processing. The sequence diagram explaining a mode that this invention was implemented using home agent address discovery. The format figure of a home agent address discovery request message. The format figure of a home agent address discovery reply message. The block diagram which shows the internal structure of the home agent used by this invention. The conceptual diagram explaining the structure of a HA substitution apparatus management table. The flowchart explaining the HA substitute apparatus search process of a mobile router by the HA substitute apparatus address inquiry to a home agent, and the flowchart explaining an HA substitute apparatus address management process. The sequence diagram explaining a route optimization procedure in the case of managing an HA substitution device address in a home agent. FIG. 6 is a format diagram of an HA proxy device address inquiry message. FIG. 6 is a format diagram of an HA proxy device address response message. The block diagram which shows the internal structure of the communicating party used by this invention. The flowchart explaining the HA substitute apparatus search process of a mobile router by the HA substitute apparatus address inquiry with respect to a communicating party. The sequence diagram explaining the route optimization procedure in the case of managing the HA proxy device address in the communication partner. 1 is a conceptual diagram of a network to which the present invention is applied, in which an HA proxy device address management server is arranged. The block diagram which shows the internal structure of the HA substitution apparatus address management server used by this invention. 6 is a flowchart for explaining an HA proxy device search process of a mobile router by an HA proxy device address inquiry to the HA proxy device address management server. The sequence diagram explaining a route optimization procedure in the case of managing a HA substitution device address in a HA substitution device address management server. The block diagram which shows the internal structure of the HA substitution apparatus used by this invention. The block diagram which shows the internal structure of the communicating party used by this invention. When using the hop-by-hop option, a flowchart explaining the HA proxy device search processing of the mobile router, a flowchart explaining the HA proxy device address notification processing of the communication partner, and the HA proxy device address notification processing of the HA proxy device Flowchart. The sequence diagram explaining the route optimization procedure using the HA proxy device address search option. Inquiry message using the HA proxy device address search option. Reply message using the HA alternate device address search option. A processing flow when the mobile router 102 moves. An example of arrangement of the HA substitution device 104.

Explanation of symbols

101 ... Home agent 102 ... Mobile router 103 ... Fixed terminal 104 ... Home agent agent device 105, 106 ... Communication partner 12
107 ... HA proxy device address management server 111 ... Home network 112 ... Visited network 113 ... Internet 114 ... Mobile network 121 ... Packet sent from fixed terminal to communication partner 1 122 ... Packet from fixed terminal to communication partner 1 encapsulated Packet 123 sent to home agent ... packet decapsulated by home agent and sent to communication partner 1 ... packet 125 sent from communication terminal to communication partner 2 ... packet from fixed terminal to communication partner 2 Packet 126 sent to the HA substitution device ... packet 201 decapsulated by the HA substitution device and sent to the communication partner 2 ... CPU
202 ... Memory 203 ... Buses 204, 205, 206 ... Interfaces 207, 208, 209 ... Line 211 ... Mobile IP processing 212 ... Basic OS processing 213 ... HA proxy device address table 214 ... Binding list 215 ... Registration CoA selection processing 216 ... HA Proxy device address search processing 217 ... Movement detection processing 218 ... Mobile IP message processing 219 ... Tunnel routing header processing 220 ... Packet transmission / reception processing 301 ... Communication partner address 302 ... Counter 303 ... State 304 ... HA proxy device address 305 ... Priority 306 ... HA proxy device address 307 ... Tunnel interface 308 ... Registered CoA
801 ... IPv6 header 802 ... Home agent address discovery request 901 ... Home agent address discovery reply 1101 ... Communication partner address 1102 ... HA agent device address 1103 ... Priority 1401 ... HA agent device address inquiry message 1501 ... HA agent device address response message 1001 1601, 2001, 2301 ... CPU
1002, 1602, 2002, 2302 ... memories 1003, 1603, 2003, 2303 ... buses 1004, 1005, 1604, 2004, 2304, 2305 ... interfaces 1006, 1007, 1605, 2005, 2306, 2307 ... lines 1011, 1611, 2011, 2311 ... Mobile IP processing 1012, 1612, 2012, 2312 ... Basic OS processing 1013, 1613, 2013 ... HA substitution device management tables 1015, 1614, 2014 ... HA substitution device address management processing 1019, 1615, 2015, 2319 ... Tunnel processing 1020 1616, 2016 ... Packet transmission / reception processing 1014, 2314 ... Binding cache 1016, 2316 ... Binding management processing 1017, 2317 ... Address selection Physical 1018,2318 ... Mobile IP message processing 2315 ... HA proxy device address notification process 2320 ... packet reception processing 2401 ... HA proxy device address notification process 2701 ... HA proxy device address search option 2702 ... ICMP Echo request
2802 ... ICMP Echo reply

Claims (13)

A movable first node;
A home agent that is arranged in a home network that is a network to which the first node belongs, and that performs communication processing including encapsulation and decapsulation for communication packets of the first node;
A second node in communication with the first node;
A home agent agent device that is arranged for the second node and performs communication processing including encapsulation and decapsulation for communication packets of the second node;
When the first node moves to another network connected to the home network, during the communication with the second node via the home agent arranged in the home network, in the moved network,
The first node creates and transmits a signal for searching for the home agent agent device, receives a response corresponding to the signal including an address of the home agent agent device, and receives the response according to the signal. Execute the search process to get the address of
The first node communicates with the second node without passing through the home agent via the home agent proxy device according to the second node according to the acquired address. . The mobile network system according to claim 1,
The mobile network system, wherein the first node is a mobile terminal, or includes a mobile router and a terminal that communicates with the mobile router. The mobile network system according to claim 1,
The mobile network system, wherein the second node is a mobile terminal or a fixed terminal. The mobile network system according to claim 1,
The search process includes
The first node uses the upper bit corresponding to the upper bit from the transmission destination address of the packet to the second node, and uses the anycast address predetermined for the home agent as the lower bit. Creating an address and sending a home agent search request addressed to the address;
When the home agent proxy device receives a home agent search request, it returns a home agent search reply including at least the address of the home agent proxy device to the first node;
The mobile network system, wherein the first node receives a reply for searching for a home agent and acquires an address of the home agent agent device in the reply. The mobile network system according to claim 1,
The home agent is
A proxy device management table for storing the address or prefix of the second node and the address of the home agent proxy device in association with each other;
The search process includes
The first node sends an inquiry signal including an address or prefix of the second node to the home agent;
In response to the inquiry signal, the home agent refers to the proxy device management table to acquire the address or prefix of the home agent proxy device corresponding to the address or prefix of the second node included in the signal, Returning a response signal including the acquired address to the first node;
The mobile network system, wherein the first node receives a response signal and acquires an address of a home agent agent device included in the response signal. The mobile network system according to claim 5, wherein
The mobile network system, wherein the address or prefix of the second node and the address of the home agent agent device stored in the agent device management table are transmitted from the home agent agent device to the home agent. The mobile network system according to claim 1,
The second node is
A proxy device management table for storing the address of the home agent proxy device corresponding to the own node;
The search process includes
The first node transmits an inquiry signal for searching for the home agent agent device to the second node;
The second node returns, in response to the inquiry signal, a response signal including an address of the home agent agent device stored in the agent device management table to the first node;
The mobile network system, wherein the first node receives a response signal and acquires an address of a home agent agent device included in the response signal. The mobile network system according to claim 1,
An address management server for storing the address or prefix of the second node and the address of the home agent agent device in association with each other;
The search process includes
The first node sends an inquiry signal including an address or prefix of the second node to the address management server;
In response to the inquiry signal, the address management server returns a response signal including the address of the second agent included in the signal or the address of the home agent proxy device corresponding to the prefix to the first node. To do
The mobile network system, wherein the first node receives a response signal and acquires an address of the home agent agent device included in the response signal. The mobile network system according to claim 1,
The search process includes
An option header is added to at least the home agent proxy device with its own address and transferred from the second node to the first node, or from the first node to the second node. Sending a search packet for searching for a home agent agent device,
The home agent agent device adds a self-address to the search packet to which the option header is added, and transfers the search packet;
The first node receives a search packet from the second node to which an address of the home agent proxy device is added, or receives a search packet from the second node in the search packet. Receiving the address of the home agent agent device and obtaining the address of the home agent agent device. The mobile network system according to claim 1,
A plurality of the home agent agent devices are arranged for a plurality of nodes,
The mobile network system, wherein a response including an address of the home agent agent device is transmitted to the first node for the home agent agent device with respect to the second node of the plurality of home agent agent devices. The mobile network system according to claim 4, wherein
A plurality of the home agent agent devices are arranged in the network of the second node,
Each of the home agent agent devices has an address list including the addresses of other home agent agent devices belonging to the same network and the own address, and
When any of the plurality of home agent proxy devices receives a home agent search request, it returns a reply for home agent search including the address list,
The mobile node network system in which the first node communicates with the second node according to one of the addresses of the plurality of home agent agent devices included in a reply for searching for a home agent. The mobile network system according to claim 1,
The first node is:
The home agent agent device which is created between the address of the home agent agent device, the care-of address of the moved network registered in the home agent agent device, and the first node and the home agent agent device. A binding list in which identifiers of tunnel interfaces for communicating with
The first node further includes:
Select a care-of address to register with the home agent agent device,
Based on the selected care-of address, perform a binding update process for registering the care-of address in the home agent agent device and / or for creating a tunnel interface,
The mobile network system that stores an address of the home agent agent device, a selected care-of address, and a tunnel interface identifier of the created tunnel interface in the binding list. The mobile network system according to claim 1,
While the first node and the second node are communicating via the home agent,
When the load on the home agent exceeds a predetermined amount, the first node executes the search process to acquire the address of the home agent agent device, and communicates via the home agent. The mobile network system which switches communication to the communication via the home agent agent device according to the acquired address.

Images