WO2007036146A1 - A METHOD, SYSTEM AND DEVICE FOR COMMUNICATING BETWEEN IPv6 MOBILE NODE AND IPv4 COMMUNICATION PARTNER - Google Patents

Abstract

A method, a system and a device are used to communicate between IPv6 mobile node and IPv4 communication partner. The method includes: IPv6 home agent acquiring information of IPv4 home address and IPv4 home agent address, and information of IPv6 home address and IPv6 care-of address; then the communication between IPv6 mobile node and IPv4 communication partner being achieved on the basis of the address information acquired cooperating with IPv4 home agent. The method enables the mobile node only to use Mobile IPv6 technique, in virtue of IPv6 home agent and IPv4 home agent allocated in network, to resolve the mobility of IPv6 and IPv4 simultaneously. The method simplifies the complexity of mobile node realization, and does not depend on special gateway device, mobile access network may not be dual stack or IPv6 and IPv4 network overlaps, these enable the application of simultaneously providing IPv6 and IPv4 mobility to be carried on and deployed more easily.

Description

 TECHNICAL FIELD The present invention relates to the field of communications, and in particular, to a method, system, and apparatus for communicating between an IPv6 mobile node and an IPv4 communication partner.

Background technique

 With the development of network technology and the emergence of a large number of mobile terminals, such as notebook computers, personal digital assistants, mobile phones, and in-vehicle devices, etc., the mobile computing boom has arisen, and more and more users hope to pass various terminals. Mobile services are connected to the Internet (Internet) through a public mobile wireless network at any location.

 In order to solve the demand of mobile services, Mobile IP (Mobile IP) technology is introduced at the network level, so that mobile nodes can always use the initial IP address (called home address) for IP communication during the mobile process, thus making the IP network layer The upper application of the bearer remains uninterrupted and contiguous in motion.

 For IPv4 and IPv6 networks, Mobile IP technology can be implemented by Mobile IPv4 and Mobile IPv6 respectively, called Mobile IPv4 technology and Mobile IPv6 technology.

 The structure of an IPv4 network using Mobile IPv4 technology is shown in Figure 1. The communication process between the mobile node 110 and the communication partner 120 includes:

 Step 1. The mobile agent (including the home agent 130 and the foreign agent 140) advertises its own existence through the proxy announcement message; the mobile node 110 may also send a proxy request message requesting the mobile agent to send the proxy announcement message;

 Step 2: When the mobile node 110 receives the proxy advertisement message, it may determine, according to the proxy advertisement message, whether the network is the foreign network 190 or the home network 180;

 Step 3. When the mobile node 110 confirms that it is located in the home network 180, it does not need to use the mobile IP address, and uses its home address for external communication. When the mobile node 110 confirms that it is in the foreign network, it first needs to obtain a care-of address. This care-of address can be obtained through a foreign agent announcement message (foreign agent care-of address) or via a DHCP server (not shown) (called a co-located care-of address).

Step 4: The mobile node 110 sends information such as a home address and a care-of address through a registration request message. Register with the home agent 130. There are two methods: 1) If the care-of address is obtained through the foreign agent 140, the mobile node 110 must relay the registration message to the home agent 130 via the foreign agent 140; 2) if the care-of address is a co-located care-of address, and the foreign agent 140 Not required, the mobile node 110 can register directly with the home agent 130.

 After receiving the registration request message, the home agent 130 records information such as the home address and the care-of address, and responds to the mobile node 110 with a registration response message.

 The registration process ends when the mobile node 110 receives the registration response message.

 Step 5. The mobile node 110 directly transmits the data packet to the communication partner 120, or transmits it to the home agent 130 through the reverse tunnel, and then forwards it to the communication partner 120 by the home agent 130.

 Step 6. The data packet (the destination is the home address) sent by the communication partner 120 to the mobile node 110 is intercepted by the home agent 130 and transmitted to the care-of address of the mobile node 110 through the tunnel encapsulation.

 Step 7. The mobile node 110 decapsulates the tunnel message; or the foreign agent 140 decapsulates the tunnel message and delivers the data packet to the mobile node 110.

 The structure of the IPv6 network using Mobile IPv6 is shown in Figure 2. The communication process between the mobile node 210 and the communication partner 220 includes:

 Step 11. When the mobile node 210 is connected to its home network 280, it operates in the same manner as other fixed nodes.

 Step 12: The mobile node 210 detects whether it has roamed to the foreign network 290 through the IPv6 neighbor discovery mechanism. The IPv6 foreign gateway 240 periodically sends a router advertisement message, which includes the prefix of the foreign network. After receiving the router advertisement message of the foreign gateway, the mobile node 210 checks that the prefix of the foreign network is different from the prefix of the home network, and then considers Roamed to the foreign network to 290.

 Step 13. When the mobile node 210 finds that it has moved to the foreign network 290, it obtains the care-of address on the foreign network through the stateful or stateless address auto-configuration process based on the received router advertisement information. At this time, the mobile node 210 has both the home address and the care-of address.

Step 14. The mobile node 210 registers its care-of address with the "Binding Update" message to the home agent 230. The home agent 230 maintains information such as the home address and the care-of address according to the content of the message, so as to proxy the mobile node to send and receive messages. Step 15. The mobile node 210 notifies the communication partner 220 of the care-of address through the "Binding Update" message to implement the "route optimization" mode of communication.

 Step 16. If the communication partner 220 of the mobile node 210 does not know its care-of address, the data packet will be sent to the mobile node's home network 280 according to the mobile node's home address, and then the home agent 230 will intercept the data packet. The data packets are forwarded to the mobile node 210 using a tunneling mechanism based on the current care-of address of the mobile node. In the opposite direction, the mobile node 210 sends the message to the communication partner 220, which is first sent to the home agent 230 through the reverse tunnel, and then forwarded to the communication partner 220 by the home agent 230.

 If the communication partner 220 knows the care-of address of the mobile node through the "binding update", the data packet is directly sent to the mobile node 210 in the foreign network without being transited by the home agent. In the opposite direction, the mobile node 210 also directly transmits data packets to the communication partner, that is, the communication in the "route optimization" mode.

 In order to realize the smooth transition from the IPv4 network to the IPv6 network, it is necessary to solve the problem of communication between the IPv6 mobile node and the IPv4 communication partner. In a prior art technical solution, the mobile node is required to support both the Mobile IPv6 technology and the Mobile IPv4 technology. Two sets of mobile agents (including home agents or foreign agents) are set up for Mobile IPv6 technology and Mobile IPv4 technology respectively. Mobile IPv6 technology is used when mobile nodes access IPv6 communication partners, and Mobile IPv4 technology is used when accessing IPv4 communication partners.

 Although the prior art completely solves the problem that the mobile node accesses the IPv6 and IPv4 communication partners at the same time, it requires the mobile node to support both Mobile IPv6 and Mobile IPv4, which increases the implementation complexity of the mobile node and is not conducive to lightweight mobile. Terminal implementation also causes duplication and redundancy of mobile IP processing. In addition, the prior art requires that the mobile access network must be dual-stacked or overlapped between the IPv6 network and the IPv4 network to simultaneously support Mobile IPv6 and Mobile IPv4 processing of the mobile node, which increases the difficulty of deployment.

 In another prior art, IPv6 mobile node and IPv4 communication partner communication are implemented by using Mobile IPv6 in conjunction with NAT-PT (Network Address Translation-Protocol Translation), and the network architecture is as shown in FIG. The process includes:

Step 21: When the IPv6 mobile node 310 moves to the foreign network 390, after obtaining the IPv6 care-of address, it first registers with the home agent 330 through a "binding update" message. Step 22: Before sending the data packet to the IPv4 communication partner 320, the IPv6 mobile node 310 obtains the corresponding IPv6 address of the IPv4 communication partner (the specific method is the same as the normal NAT-PT application) as the destination address of the data packet, and the source address is the IPv6 mobile node. The home address is then sent to the home agent 330 through the reverse tunnel, and the data packet is sent to the IPv4 communication partner 320 by the home agent.

 Step 23: Since the destination address of the data packet is an IPv6 address corresponding to the IPv4 communication partner, the data packet is sent to the NAT-PT gateway 360, and at the NAT-PT gateway 360, the IPv6 data packet is converted according to the NAT-PT protocol requirement. For an IPv4 packet, where the destination address of the packet is translated to the IPv4 address of the IPv4 communication partner, the IPv6 source address (ie, the home address) is converted to an IPv4 address (set to tranSourceIPv4) assigned from the NAT-PT gateway IPv4 address pool. .

 Step 24. The converted IPv4 data packet is sent from the NAT-PT gateway 360 to the IPv4 communication partner 320. The packet returned from the IPv4 communication partner 320 to the IPv6 mobile node 310 has a destination address of tranSourceIPv4.

 Step 25. The data packet returned by the IPv4 communication partner 320 arrives at the NAT-PT gateway 360, and the NAT-PT gateway 360 converts the data packet into an IPv6 data packet. The translated destination address is the home address of the IPv6 mobile node.

 Step 26: The converted data packet is first intercepted by the home agent 330, and then the data packet is sent to the IPv6 mobile node 310 through the tunnel according to the handover address of the mobile node.

 Step 27: The IPv6 mobile node 310 receives the IPv6 data packet returned by the IPv4 communication partner from the tunnel, and completes the processing.

 The prior art solves the problem of IPv6 mobile node and IPv4 communication by using the "triangular routing" mode of Mobile IPv6 in conjunction with NAT-PT. Since all communication data packets are converted by the NAT-PT gateway, the NAT-PT gateway is easy to become Bottlenecks, reducing network efficiency. In addition, the NAT-PT gateway has a problem of conversion to some application layers, and there is a lack of scalability.

Summary of the invention

 The invention provides a method, a system and a device for communicating between an IPv6 mobile node and an IPv4 communication partner, which can improve the efficiency of the network without depending on a special gateway device.

 According to one aspect of the present invention, a method for an IPv6 mobile node to communicate with an IPv4 communication partner includes:

An IPv6 home agent obtains address information of the IPv6 mobile node, where the address information includes An IPv4 home address and an IPv4 home agent address, and an IPv6 home address and an IPv6 care-of address; the IPv6 home agent performs an IPv4 home agent corresponding to the IPv4 home agent address

Registration of IPv6 mobile nodes;

 After registration, the IPv6 home agent cooperates with the IPv4 home agent to forward data between the IPv6 mobile node and the IPv4 communication partner.

 Optionally, the obtaining, by the IPv6 home agent, the address information of the IPv6 mobile node, includes: when the IPv6 mobile node moves to a foreign network, obtains an IPv6 care-of address, constructs a binding update message, and registers with an IPv6 home agent. Specifying an IPv4 home address and an IPv4 home agent address in the binding update message;

 After receiving the binding update message, the IPv6 home agent obtains an IPv6 home address and

IPv6 care-of address, and IPv4 home address and IPv4 home agent address.

 Optionally, the constructing the binding update message includes:

 The IPv6 mobile node adds an IPv4 registration mobility option to the binding update message; the IPv4 home address and the IPv4 home agent address are indicated in the IPv4 registration mobility option. Optionally, before the IPv6 home agent performs registration of the IPv6 mobile node with the IPv4 home agent corresponding to the IPv4 home agent address, the method further includes:

 The IPv6 home agent responds to the IPv6 mobile node with an IPv6 binding acknowledgement message according to the IPv6 home address and the IPv6 care-of address information;

 According to the IPv4 home address and the IPv4 home agent address information, it is checked whether the IPv6 mobile node corresponding to the IPv4 home address has been proxyed, and the registration is performed when it is confirmed that the agent has passed the IPv6.

 Optionally, the IPv6 home agent performs registration of the IPv6 mobile node to the IPv4 home agent corresponding to the IPv4 home agent address, including:

 The IPv6 home agent constructs an IPv4 registration request message, the IPv4 home agent address is used as the destination address of the registration request message, and the IPv4 home agent's IPv4 address is used as the source address of the registration request message;

 Transmitting the constructed IPv4 registration request message to the IPv4 home agent instead of the IPv6 mobile node, and recording the address information;

The IPv4 home agent obtains an IPv4 home address from the received registration request message And record and record the IPv4 address of the IPv6 home agent, and respond to the registration response message to the IPv6 home agent. Optionally, the method further includes: after confirming that the registration response message is valid, the IPv6 home agent validates an agent function corresponding to the IPv4 home address of the IPv6 mobile node, and validates the recorded address information.

 Optionally, the replacing the IPv6 mobile node sends the configured IPv4 registration request message to the IPv4 home agent, specifically:

 When the IPv6 home agent supports the Han stack and has at least one IPv4 address and has an IPv4 network connection, directly transmitting the constructed IPv4 registration request message to the IPv4 home agent instead of the IPv6 mobile node; or

 When the IPv6 home agent supports the dual stack and has at least one IPv4 address and does not have an IPv4 network connection, the IPv4 over IPv6 tunnel or the universal route encapsulation tunnel is used to replace the IPv6 mobile node to send the constructed IPv4 registration request message to the IPv4 home agent. ; or,

 When the IPv6 home agent confirms that no IPv4 address is used, the network address translation method is used instead of the IPv6 mobile node to send the constructed IPv4 registration request message to the IPv4 home agent.

 Optionally, the IPv6 home agent cooperates with the IPv4 home agent to forward data between the IPv6 mobile node and the IPv4 communication partner, including:

 The IPv6 home agent searches for the corresponding IPv4 home agent address according to the IPv4 home address carried by the IPv4 mobile node and the IPv4 home address carried by the IPv4 mobile partner, and sends the IPv4 data packet to the IPv4 home agent according to the IPv4 home agent address. Sent to the IPv4 communication partner through the IPv4 home agent; and/or,

 The IPv4 home agent intercepts the IPv4 data packet sent by the IPv4 communication partner to the IPv6 mobile node, and sends the IPv4 home agent address to the corresponding IPv6 home agent according to the IPv4 home address carried in the data packet, and confirms the IPv4 home address carried by the IPv6 home agent in the IPv4 data packet. When the IPv6 mobile node corresponding to the IPv4 home address is dequeued, the IPv4 data packet is sent to the IPv6 mobile node.

 Optionally, the IPv6 mobile node sets an IPv4 home agent as an IPv4 gateway, and sets an outgoing interface of the IPv4 gateway as an IP v6 reverse tunnel on the mobile node;

 The IPv6 home agent cooperates with the IPv4 home agent to forward data between the IPv6 mobile node and the IPv4 communication partner, including:

The IPv6 mobile node passes the IPv4 data packet sent to the IPv4 communication partner through the IPv6 The reverse tunnel is encapsulated into an IPv6 data packet and transmitted to the IPv6 home agent; wherein, the destination address of the IPv4 data packet is an IPv4 communication partner, and the source address is an IPv4 home address of the IPv6 mobile node; the destination address of the IPv6 data packet is IPv6 home agent, the source address is the IPv6 care-of address of the IPv6 mobile node;

 Decapsulating the IPv6 data packet by the IPv6 home agent, and restoring the IPv4 data packet sent to the IPv4 communication partner;

 The IPv6 home agent sends the IPv4 data packet to the IPv4 communication partner when it confirms that the IPv4 home address has been proxied.

 Optionally, the sending, by the IPv6 home agent, the source address information of the IPv4 home address carried by the IPv4 data packet, instead of the IPv6 mobile node, is sent to the IPv4 communication partner. Find and obtain the IPv4 home agent address corresponding to the IPv4 home address in the information recorded by the process of registering the IPv4 home agent;

 The IPv4 data packet is encapsulated and sent to the corresponding IPv4 home agent through an IPv4 reverse tunnel whose destination address is an IPv4 home agent and whose source address is an IPv6 home agent.

 After receiving the encapsulated IPv4 data packet, the corresponding IPv4 home agent decapsulates the data packet, restores the IPv4 data packet, and carries the IPv4 home address according to the restored IPv4 data packet. When the source address information confirms that the IPv4 home address has been proxied, the IPv4 data packet is sent to the corresponding IPv4 communication partner.

 Optionally, the IPv4 data packet is encapsulated and sent to a corresponding IPv4 home agent, and specifically includes:

 When the IPv6 home agent supports the dual stack and has at least one IPv4 address and has an IPv4 network connection, the IPv4 data packet is encapsulated by the IPv4 reverse tunnel and sent to the corresponding IPv4 home agent; or

 When the IPv6 home agent supports the dual stack and has at least one IPv4 address and does not have an IPv4 network connection, the IPv4 data packet is encapsulated by the IPv4 reverse tunnel, and then encapsulated by an IPv4 Over IPv6 tunnel or a general routing. The tunnel is sent to the corresponding IPv4 home agent.

Optionally, the IPv6 home agent cooperates with the IPv4 home agent to forward data between the IPv6 mobile node and the IPv4 communication partner, including: The IPv4 home agent intercepts an IPv4 data packet sent from the IPv4 communication partner to the IPv6 mobile node, and encapsulates the IPv4 data packet into a corresponding IPv4 data packet, and then sends the IPv4 data packet to the IPv4 home address corresponding to the IPv6 mobile node. IPv6 home agent;

 After the IPv6 home agent de-encapsulates the received IPv4 data packet, the IPv4 data packet sent to the IPv6 mobile node is restored, and the IPv4 data packet of the restored IPv4 data packet is the destination address of the IPv4 home address. The IPv4 data packet is sent to the IPv6 mobile node.

 Optionally, the sending, by the IPv4 data packet, the IPv4 mobile node to the IPv4 mobile node, according to the destination address of the IPv4 home address carried by the restored IPv4 data packet, replacing the IPv6 mobile node with the IPv4 mobile home Find and obtain the IPv6 care-of address corresponding to the IPv4 home address in the information recorded by the agent registration process;

 Sending the IPv4 data packet to the IPv6 mobile node according to the obtained IPv6 care-of address

 Optionally, the sending the IPv4 data packet to the IPv6 mobile node includes: checking whether an IPv6 tunnel to the IPv6 care-of address is existing, and if yes, using the IPv6 tunnel to send the IPv4 data packet. Encapsulate into an IPv6 data packet and send it to the IPv6 mobile node; otherwise, establish an IPv6 tunnel to the IPv6 care-of address, then encapsulate the IPv4 data packet into an IPv6 data packet through the IPv6 tunnel, and send it to the IPv6 Mobile node.

 Optionally, the method further includes: after the decapsulating the received IPv6 data packet, the IPv6 mobile node restores the IPv4 data packet, and uploads the IPv4 data packet to the application layer for receiving processing.

 According to another aspect of the present invention, a mobile IP communication system, including an IPv4 home agent, an IPv4 communication partner, further includes:

 An IPv6 mobile node, configured to provide address information to an IPv6 home agent, where the address information includes an IPv4 home address and an IPv4 home agent address, and an IPv6 home address and an IPv6 care-of address;

An IPv6 home agent, configured to obtain address information of the IPv6 mobile node; perform IPv6 mobile node registration with an IPv4 home agent corresponding to the IPv4 home agent address; and forward an IPv6 mobile node to an IPv4 communication partner with an IPv4 home agent data.

 According to still another aspect of the present invention, an IPv6 home agent includes:

Address information obtaining unit, for obtaining an IPv4 IPv6 mobile node home address and home agent address IPv ^4, IPv6 and IPv6 home address and care-of address; An IPv4 registration unit, configured to register an IPv6 mobile node with an IPv4 home agent corresponding to the IPv4 home agent address;

 The data forwarding unit is configured to cooperate with the IPv4 home agent to forward data between the IPv6 mobile node and the IPv4 communication partner.

 Optionally, the address information obtaining unit is a binding update message parsing unit, configured to obtain an IPv6 home address and an IPv6 care-of address, and an IPv4 home address and an IPv4 home agent address from a binding update message of the IPv6 mobile node.

 Optionally, the IPv4 registration unit includes:

 An IPv4 registration request message constructing unit is configured to use an IPv4 home agent address as a destination address of the registration request message, and construct an IPv4 registration request message by using an IPv4 home agent IPv4 address as a source address of the registration request message;

 The IPv4 registration request message sending unit is configured to send the constructed IPv4 registration request message to the IPv4 home agent instead of the IPv6 mobile node.

 Optionally, the data forwarding unit includes:

 An IPv6 packet decapsulation unit, configured to decapsulate an IPv6 data packet from an IPv6 mobile node, and restore an IPv4 data packet sent to the IPv4 communication partner;

 An IPv4 data packet encapsulating unit, configured to encapsulate the IPv4 data packet by using an IPv4 reverse tunnel whose destination address is an IPv4 home agent and an IPv6 home agent address;

 An IPv4 data packet sending unit is configured to send the encapsulated IPv4 data packet to a corresponding IPv4 home agent.

 Optionally, the data forwarding unit includes:

 The IPv4 data packet decapsulation unit is configured to: after decapsulating the IPv4 data packet from the IPv4 home agent, to restore the IPv4 data packet sent to the IPv6 mobile node;

 An IPv6 data packet encapsulating unit, configured to encapsulate the IPv4 data packet into an IPv6 data packet by using an IPv6 tunnel to an IPv6 care-of address;

 An IPv6 packet sending unit is configured to send the encapsulated IPv6 data packet to the IPv6 mobile node.

The IPv6 home agent of the present invention obtains an IPv4 home address and an IPv4 home agent address information of an IPv6 mobile node, and an IPv6 home address and an IPv6 care-of address information; The address information is replaced by the IPv6 mobile node to register with the IPv4 home agent, and the IPv4 home agent is used to communicate with the IPv4 mobile node. By not relying on special gateway devices, the efficiency and reliability of the network can be improved. In addition, the mobile node can only use Mobile IPv6 technology, and solve the mobility of IPv6 and IPv4 by using the deployed IPv6 home agent and IPv4 home agent in the network, thereby simplifying the complexity of mobile node implementation.

 In addition, the mobile access network may not need to be dual-stack or overlap between IPv6 and IPv4 networks, which makes applications that support both IPv6 and IPv4 mobility easier to deploy and deploy.

DRAWINGS

 1 is a schematic diagram of an IPv4 network using the Mobile IPv4 technology in the prior art; FIG. 2 is a schematic diagram of an IPv6 network using the Mobile IPv6 technology in the prior art; FIG. 4 is a schematic structural diagram of an embodiment of a mobile IP communication system according to the present invention; Figure 5 is a flowchart of an embodiment of a communication method of the present invention;

 6 is a flowchart of performing IPv4 registration in an embodiment of a communication method according to the present invention; FIG. 7 is a flowchart of performing data forwarding in an embodiment of a communication method according to the present invention; FIG. 8 is an embodiment of an IPv6 home agent according to the present invention; Block diagram.

DETAILED DESCRIPTION OF THE INVENTION In the present invention, an IPv6 home agent obtains an IPv4 home address and an IPv4 home agent address information of an IPv6 mobile node, and an IPv6 home address and an IPv6 care-of address information; and replaces an IPv6 mobile node with an IPv4 home agent based on the acquired address information. Registration, on the basis of this, cooperate with the IPv4 home agent to realize the communication between the IPv6 mobile node and the IPv4 communication partner.

 The embodiment provided by the present invention implements IPv4 mobility of the mobile node by improving the Mobile IPv6 technology, and mainly includes using the IPv6 home agent as a secondary agent to cooperate with the IPv4 home agent to implement the mobile node's IPv4 mobility capability.

 Please refer to FIG. 4, which is a schematic structural diagram of a mobile IP communication system according to the present invention.

The system includes an IPv6 network 400 and an IPv4 network 900. The IPv6 mobile node 410 supporting the dual stack has both an IPv6 home address and an IPv4 home address, and learns the IPv6 home agent address and the IPv4 home agent address. The home address of IPv4 and the recipient of the IPv4 home agent address , can be static configuration or other dynamic methods.

 In the IPv6 network 400, when the IPv6 mobile node 410 is in the foreign network 490, it can communicate externally through the IPv6 home agent 420 in its home network 480. The IPv4 network 900 includes an IPv4 home agent 910 corresponding to the IPv6 mobile node 410 and an IPv4 communication partner 920 that needs to communicate with the IPv6 mobile node 410. The IPv6 home agent 420 cooperates with the IPv6 home agent 420 to implement communication between the IPv6 mobile node 410 and the communication partner 920.

 In the present invention, the IPv6 mobile node 410 does not need to obtain an IPv4 care-of address after moving to the foreign network 490, and always uses an IPv4 home address and external communication.

 Referring to FIG. 5, a flow of an implementation manner of a communication method of the present invention includes:

 Step S510: The IPv6 home agent obtains address information of the IPv6 mobile node, where the address information includes an IPv4 home address and an IPv4 home agent address, and an IPv6 home address and an IPv6 care-of address;

 Step S520, the IPv6 home agent performs registration of the IPv6 mobile node to the IPv4 home agent corresponding to the IPv4 home agent address;

 Step S530: The IPv6 home agent cooperates with the IPv4 home agent to forward data between the IPv6 mobile node and the IPv4 communication partner.

 In an embodiment of the present invention, when the mobile node moves to the foreign network, after obtaining the IPv6 care-of address, the address information is transmitted to the IPv6 home agent through the extension of the binding update message. That is, the IPv6 mobile node constructs a binding update message, and specifies an IPv4 home address and IPv4 home agent address information in the binding update message. Specifically include:

 First, the IPv6 mobile node adds an IPv4 registration mobility option after binding the update message, and then indicates the IPv4 home address and the IPv4 home agent address information in the IPv4 registration mobility option.

 The format of the binding update message constructed in the present invention can be as follows:

 0 1 2 3

 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

 +_+.-)-_+-+-+-+-+-+-+-+-+-+-+-+-+

 I Type = 10 | Length = 8 |

 +_+-+.+.+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+

 ] IPv4 Home Address I

 +—+_+— +—+_+—+_+-+_+-+_+_+—+_+-+—+_+-+-+_+—+—+_+_+_ +-+-+-+- +-+-+-+

 I IPv4 Home Agent |

+-+-+_+_+—+—+_+—+—+_+—+_+—+-+_+_+-+_+—+—+-+-+_+_+- +-+-+-+-+-+-+-+ The Type value can be determined according to the value of the actual standard organization application. The IPv4 Home Address is the IPv4 home address, and the IPv4 Home Agent is the IPv4 home agent address.

 Referring to FIG. 6, after the IPv6 home agent receives the "binding update" message, the IPv6 home agent replaces the mobile node to send an IPv4 registration request to the IPv4 home agent according to the information such as the IPv4 home address and the IPv4 home agent address carried in the message content. Message. Specifically include:

 Step S610: After receiving the binding update message, the IPv6 home agent obtains an IPv6 home address and an IPv6 care-of address information, and an IPv4 home address and an IPv4 home agent address information according to the binding update message content.

 Step S620: The IPv6 home address and the IPv6 care-of address information are obtained, and the IPv6 "binding confirmation" message is sent to the IPv6 mobile node; and according to the obtained IPv4 home address and the IPv4 home agent address information, it is checked whether the user has already The agent obtains the obtained IPv4 home address, and if it is confirmed that the agent has been authenticated, step S630 is executed to end the process of registering with the IPv4 home agent; if it is confirmed that the agent has not been agentd, step S640 is performed.

 Step S640: The IPv6 home agent uses the IPv4 home agent address as the destination address of the registration request message, and uses the IPv4 home agent's IPv4 address as the source address of the registration request message to construct an IPv4 registration request message. The specific process is:

 First, the IPv4 home agent address is used as the destination address of the registration request message; the IPv4 address of the IPv6 home agent is used as the source address of the registration request message. It is equivalent to the IPv4 address of the IPv6 home agent as the IPv4 Co-Located care-of address of the mobile node.

 Next, the IPv4 registration request message can be constructed in the following format: (can be sent over the socket) IPv4 domain:

 Source address = IPv6 address of the IPv6 home agent

 Destination address = IPv4 home agent address

 TTL = 64

 UDP domain:

 Source Port = <any > (system customization)

 Destination Port = 434

Registration request domain: One possible specific format is:

 0 1 2 3

 01234567890123456789012345678901

 1 Type |S]B|D|M|G|r|T|x] Lifetime |

 +-+-+-+-+-+-+-+-+-+_+-+_+_+_+_+-+-+_+-+-+-+_+-+_+- +_+_+-+-+-+_+-+

 I Home Address

 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+

 I Home Agent

 i - +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-·?-+-+-+-+-+-+ -+-+-+-+-+-+-+-+

 I Care-of Address I

 -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ -+-+-+-+-+-+-+

 + Identification + ii— -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-+- +

 I Extensions...

 Lf—+-+— +_+—+-+_+ one where Type = 1;

 S=0, B=0, D=1, M=1 or 0 (optional), G=l or 0 (optional);

 Lifetime - 1800 (seconds) (customizable);

 Home Address = IPv4 home address of the mobile node;

 Home Agent = IPv4 home agent address;

 Care-of Address = IPv4 address of the IPv6 home agent;

 Identification = (according to the standard of Mobile IPv4 mobile node);

 Extensions: (optional).

 Step S640: Send the constructed IPv4 registration request message to the IPv4 home agent instead of the IPv6 mobile node, and temporarily record the IPv4 home address and the IPv4 home agent address, and the corresponding IPv6 home address and IPv6 care-of address information in the cache;

 When the above message is sent to the IPv4 home agent, if the IPv6 home agent has an IPv4 network connection, the message can be directly routed to the IPv4 home agent. Otherwise, the IPv4 registration request message can be sent to the IPv4 home agent through the tunnel, for example, through IPv4. Over ΙΡνόί3⁄4, or GRE (Generic Routing Encapsulation) tunnel. Specifically, when the IPv6 home agent supports the dual stack and has at least one IPv4 address and has an IPv4 network connection, the IPv6 mobile node is directly sent to the IPv4 home agent to send the constructed IPv4 registration request message;

When the IPv6 home agent supports dual stack and has at least one IPv4 address and does not have an IPv4 network connection, the IPv6 mobile node is replaced by an IPv4 Over IPv6 tunnel or a GRE tunnel. The IPv4 home agent sends the constructed IPv4 registration request message;

 When the IPv6 home agent confirms that no IPv4 address is used, the NAT-PT method is used to replace the IPv6 mobile node to send the constructed IPv4 registration request message to the IPv4 home agent.

 Step S650, the IPv4 home agent receives the registration request message, obtains an IPv4 home address and an IPv4 care-of address (an IPv4 address of an IPv6 home agent), records it in a cache of the IPv4 home agent, and then responds to the registration response message to IPv6 home agent;

 Step S660: The IPv6 home agent receives the registration response message from the IPv4 home agent, and after confirming that the registration response message is valid, the proxy function of the IPv4 home address of the relevant mobile node is validated, and the cache is temporarily suspended. The recorded information takes effect and then ends the IPv4 mobile registration process for the proxy IPv6 mobile node.

 Please refer to FIG. 7. After the above steps, the IPv6 mobile node can exchange information with the IPv4 communication partner, and the specific implementation process includes:

 Step S710: The IPv6 mobile node sets an IPv4 home agent address as an IPv4 gateway, and sets an outgoing interface of the IPv4 gateway as an IPv6 reverse tunnel on the mobile node.

 Before communicating with the IPv4 communication partner, the mobile node can set the IPv4 home agent address as the IPv4 default gateway and set the Mobile IPv6 reverse tunnel on the mobile node (the IPv6 mobile node performs Mobile IPv6 packet processing during the mobile node and The IPv6 home agent is established as the default gateway outbound interface of IPv4, that is, all IPv4 packets sent to the outside are sent through the Mobile IPv6 reverse tunnel.

 Step S720: The IPv6 mobile node sends the IPv4 data packet to the IPv4 communication partner, and the IPv6 data packet is encapsulated into an IPv6 data packet by the IPv6 reverse tunnel, and then transmitted to the IPv6 home agent; the destination address of the IPv4 data packet is an IPv4 communication partner, and the source address is It is the IPv4 home address of the IPv6 mobile node; the destination address of the IPv6 packet encapsulated by the reverse tunnel is the IPv6 home agent, and the source address is the IPv6 care-of address of the IPv6 mobile node.

Step S730: After decapsulating the IPv6 data packet, the IPv6 home agent restores an IPv4 data packet that is sent to the IPv4 communication partner, and searches for information recorded in the process of replacing the IPv6 mobile node with the IPv4 home agent. The source address carried by the IPv4 data packet is information of an IPv4 home address, and when it is confirmed, the mobile node corresponding to the IPv4 home address is considered to be proxy, and the IPv6 mobile node is sent to the IPv6 mobile node to send the IPv4 data packet to the IPv4 communication partner Accompanying.

 The specific process of transmitting the IPv4 data packet to the IPv4 communication partner instead of the IPv6 mobile node is:

 Step 1: The IPv6 home agent searches for and obtains the IPv4 address corresponding to the IPv4 home address in the information recorded by the process of registering the IPv4 home node to the IPv4 home agent according to the source address information of the IPv4 home address carried by the IPv4 data packet. Home agent address.

 Step 2: Check whether there is an IPv4 reverse tunnel of the IPv4 home agent corresponding to the IPv4 home agent address. If yes, perform step 3 directly; if not, set the destination address to be an IPv4 home agent, and the source address is IPv6 hometown. The IPv4 address of the proxy is reverse tunneled, and then step three is performed.

 Step 3: The IPv4 data packet is encapsulated by the IPv4 reverse tunnel, and then sent to the corresponding IPv4 home agent. The destination address of the encapsulated data packet is an IPv4 home agent, and the source address is an IPv4 home agent IPv4. address. The following includes the following situations: When the IPv6 home agent supports the dual stack and has at least one IPv4 address and has an IPv4 network connection, the IPv4 data packet is encapsulated by the IPv4 reverse tunnel, and then sent to the corresponding IPv4 home agent; or,

 When the IPv6 home agent supports the dual stack and has at least one IPv4 address and does not have an IPv4 network connection, the IPv4 data packet is encapsulated by the IPv4 reverse tunnel, and then sent to the corresponding IPv4 through the tunnel. Home agent, such as IPv4 Over IPv6 tunnel or GRE tunnel; or

 When the IPv6 home agent confirms that no IPv4 address is used, the IPv4 data packet is encapsulated by the IPv4 reverse tunnel, and then sent to the corresponding IPv4 home agent through the NAT-PT.

 Step S740: After receiving the encapsulated IPv4 data packet, the corresponding IPv4 home agent performs decapsulation processing on the data packet, restores the IPv4 data packet, and carries according to the restored IPv4 data packet. The source address information of the IPv4 home address is searched for the corresponding Mobile IPv4 registration information. When it is confirmed that the corresponding information exists, the IPv4 data packet is sent to the corresponding IPv4 communication partner.

Step S750: The IPv4 communication partner sends according to the address information carried in the received data packet. IPv4 packets are sent to IPv6 mobile nodes. Specifically include:

 Step 1: After receiving the IPv4 data packet, the IPv4 communication partner obtains that the source address of the data packet is an IPv4 home address of the IPv6 mobile node.

 Step 2: Send an IPv4 data packet to the IPv6 mobile node according to the IPv4 home address of the IPv6 mobile node; the destination address of the data packet is an IPv4 home address.

 Step S760: The IPv4 home agent intercepts the data packet, and checks that the destination address of the data packet is an IPv4 home address, and the IPv4 data packet is sent to the IPv6 home agent corresponding to the IPv4 care-of address corresponding to the IPv4 home address through the tunnel.

 Since the destination address of the IPv4 data packet sent from the IPv4 communication partner to the IPv6 mobile node is the IPv4 home address, it is first intercepted by the IPv4 home agent, and the IPv4 home agent checks that the destination address of the data packet is the IPv4 home address. The IPv4 data packet is then sent through the tunnel to the IPv4 care-of address corresponding to the IPv4 home address. As mentioned earlier, the IPv4 care-of address is the IPv4 address of the IPv6 home agent, so the IPv4 packet is actually sent to the IPv6 home agent via the tunnel.

 Step S770: After the IPv6 home agent de-encapsulates the received IPv4 data packet, the IPv4 data packet that is sent to the IPv6 mobile node is restored, and according to the destination address of the IPv4 home address, the restored IPv4 data packet is used. The IPv4 data packet is sent to the IPv6 mobile node. Specifically include:

 Step 1: After the IPv6 home agent de-encapsulates the received IPv4 data packet, it restores the IPv4 data packet that is sent to the IPv6 mobile node.

 Step 2: According to the destination address of the IPv4 home address carried by the restored IPv4 data packet, searching for and obtaining the IPv6 care-of address corresponding to the IPv4 home address in the information recorded by the process of registering the IPv4 mobile node to the IPv4 home agent. .

 Step 3: Send the IPv4 data packet to the IPv6 mobile node according to the obtained IPv6 care-of address.

The IPv6 home agent can obtain the IPv6 care-of address corresponding to the IPv4 home address, and check whether there is a Mobile IPv6 tunnel to the IPv6 care-of address. If yes, the IPv4 data packet is directly encapsulated into IPv6 through the IPv6 tunnel. After the data packet is sent to the IPv6 mobile node; otherwise, the IPv6 tunnel to the IPv6 care-of address is established, and then the IPv4 data packet is encapsulated into an IPv6 data packet through the IPv6 tunnel, and then sent to the IPv6 mobile node. Step S780: The mobile node receives the IPv6 data packet, decapsulates the IPv6 data packet, and then restores the IPv4 data packet, and uploads the IPv4 data packet to the application layer for receiving processing.

 Please refer to FIG. 8, which is a block diagram of an embodiment of an IPv6 home agent according to the present invention.

 The IPv6 home agent includes: an address information obtaining unit 810, configured to obtain an IPv4 home address and an IPv4 home agent address of the IPv6 mobile node, and an IPv6 home address and an IPv6 care-of address; and an IPv4 registration unit 820, configured to send the address to the IPv4 home agent The corresponding IPv4 home agent performs registration of the IPv6 mobile node; the data forwarding unit 830 is configured to forward data between the IPv6 mobile node and the IPv4 communication partner in cooperation with the IPv4 home agent.

 The address information obtaining unit 810 may be a binding update message parsing unit, configured to obtain an IPv6 home address and an IPv6 care-of address, and an IPv4 home address and an IPv4 home agent address from the binding update message from the IPv6 mobile node.

 The IPv4 registration unit 820 includes: an IPv4 registration request message constructing unit 821, configured to use an IPv4 home agent address as a destination address of a registration request message, and construct an IPv4 registration request by using an IPv4 home agent IPv4 address as a source address of the registration request message. The IPv4 registration request message sending unit 822 is configured to send the constructed IPv4 registration request message to the IPv4 home agent instead of the IPv6 mobile node.

 The data forwarding unit 830 includes:

 An IPv6 packet decapsulation unit 831, configured to decapsulate an IPv6 data packet from an IPv6 mobile node, and restore an IPv4 data packet sent to the IPv4 communication partner;

 The IPv4 data packet encapsulating unit 832 is configured to encapsulate the IPv4 data packet by using an IPv4 reverse tunnel whose destination address is an IPv4 home agent and whose source address is an IPv6 home agent.

 The IPv4 data packet sending unit 833 is configured to send the encapsulated IPv4 data packet to the corresponding IPv4 home agent.

 The IPv4 packet decapsulation unit 834 is configured to: after decapsulating the IPv4 data packet from the IPv4 home agent, to restore the IPv4 data packet sent to the IPv6 mobile node;

 An IPv6 data packet encapsulating unit 835, configured to encapsulate the IPv4 data packet into an IPv6 data packet by using an IPv6 tunnel to an IPv6 care-of address;

The IPv6 data packet sending unit 836 is configured to send the encapsulated IPv6 data packet to the IPv6 mobile node. In the present invention, for the IPv6 mobile node requirement, only the dual stack and the Mobile IPv6 protocol are supported, and a small number of Mobile IPv6 protocol extensions (carrying the IPv4 registration mobility option in the Mobile IPv6 "Binding Message") do not need to support the Mobile IPv4 protocol. Thereby simplifying the implementation complexity of the mobile node; in addition, there is no requirement for the IPv4 home agent, no extension is needed, a standard IPv4 home agent can be applied, and the special access device is not required, and the mobile access network does not have to be a dual stack or IPv6. Overlapping with IPv4 networks makes applications that support both IPv6 and IPv4 mobility easier to deploy and deploy.

 The above description is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think of changes or within the technical scope disclosed by the present invention. Alternatively, if the IPv6 mobility of the mobile node is supported by the IPv4 mobile node in accordance with the idea of the present invention, or the IPv6 mobile node in the "route optimization" mode, the process of registering with the communication partner in accordance with the idea of the present invention should be covered. It is within the scope of the invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

Rights request

 A method for an IPv6 mobile node to communicate with an IPv4 communication partner, comprising: an IPv6 home agent obtaining address information of the IPv6 mobile node, where the address information includes

An IPv4 home address and an IPv4 home agent address, and an IPv6 home address and an IPv6 care-of address; the IPv6 home agent performs an IPv4 home agent corresponding to the IPv4 home agent address

Registration of IPv6 mobile nodes;

 After registration, the IPv6 home agent cooperates with the IPv4 home agent to forward data between the IPv6 mobile node and the IPv4 communication partner.

 The method according to claim 1, wherein the obtaining, by the IPv6 home agent, the address information of the IPv6 mobile node includes:

 After the IPv6 mobile node moves to the foreign network, after obtaining the IPv6 care-of address, constructing a binding update message, registering with the IPv6 home agent, and indicating the IPv4 home address and the IPv4 home agent address in the binding update message;

 After receiving the binding update message, the IPv6 home agent obtains an IPv6 home address and an IPv6 care-of address, and an IPv4 home address and an IPv4 home agent address.

 The method according to claim 2, wherein the constructing the binding update message comprises:

 The IPv6 mobile node adds an IPv4 registration mobility option to the binding update message; the IPv4 home address and the IPv4 home agent address are indicated in the IPv4 registration mobility option.

 The method according to claim 2, wherein before the IPv6 home agent registers the IPv6 mobile node with the IPv4 home agent corresponding to the IPv4 home agent address, the method further includes:

 The v6 home agent responds to the IPv6 mobile node with an IPv6 binding acknowledgement message according to the IPv6 home address and the IPv6 care-of address information;

 According to the IPv4 home address and the IPv4 home agent address information, it is checked whether the IPv6 mobile node corresponding to the IPv4 home address has been proxyed, and the registration is performed when it is confirmed that the IPv6 has not been represented.

The method according to claim 2, wherein the IPv6 home agent performs registration of the IPv6 mobile node to the IPv4 home agent corresponding to the IPv4 home agent address, including: The IPv6 home agent constructs an IPv4 registration request message, the IPv4 home agent address is used as the destination address of the registration request message, and the IPv4 home agent's IPv4 address is used as the source address of the registration request message;

 Transmitting the constructed IPv4 registration request message to the IPv4 home agent instead of the IPv6 mobile node, and recording the address information;

 The IPv4 home agent obtains and records the IPv4 home address and the IPv6 home agent's IPv4 address from the received registration request message, and responds to the IPv6 home agent with a registration response message.

 The method according to claim 5, further comprising: after confirming that the registration response message is valid, the IPv6 home agent validates an agent function corresponding to an IPv4 home address of the IPv6 mobile node, and Make the recorded address information take effect.

 The method according to claim 5, wherein the replacing the IPv6 mobile node sends the constructed IPv4 registration request message to the IPv4 home agent, specifically:

 When the IPv6 home agent supports the Han stack and has at least one IPv4 address and has an IPv4 network connection, directly transmitting the constructed IPv4 registration request message to the IPv4 home agent instead of the IPv6 mobile node; or

 When the IPv6 home agent supports the dual stack and has at least one IPv4 address and does not have an IPv4 network connection, the IPv4 over IPv6 tunnel or the universal route encapsulation tunnel is used to replace the IPv6 mobile node to send the constructed IPv4 registration request message to the IPv4 home agent. ; or,

 When the IPv6 home agent confirms that no IPv4 address is used, the network address translation method is used instead of the IPv6 mobile node to send the constructed IPv4 registration request message to the IPv4 home agent.

 The method according to any one of claims 1 to 7, wherein the IPv6 home agent cooperates with the IPv4 home agent to forward data between the IPv6 mobile node and the IPv4 communication partner, including:

 The IPv6 home agent searches for the corresponding IPv4 home agent address according to the IPv4 home address carried by the IPv4 mobile node and the IPv4 home address carried by the IPv4 mobile partner, and sends the IPv4 data packet to the IPv4 home agent according to the IPv4 home agent address. Sent to the IPv4 communication partner through the IPv4 home agent; and/or,

The IPv4 home agent intercepts the IPv4 data packet sent by the IPv4 communication partner to the IPv6 mobile node, and sends the IPv4 data packet to the corresponding IPv6 home agent according to the IPv4 home address carried in the data packet, when IPv6 The home agent confirms that the IPv6 mobile node corresponding to the IPv4 home address is obsolete according to the IPv4 home address carried in the IPv4 data packet, and then sends the IPv4 data packet to the IPv6 mobile node.

 The method according to any one of claims 1 to 7, wherein the IPv6 mobile node sets an IPv4 home agent as an IPv4 gateway, and sets an outbound interface of the IPv4 gateway to be an IPv6 reverse on the mobile node. Tunnel

 The IPv6 home agent cooperates with the IPv4 home agent to forward data between the IPv6 mobile node and the IPv4 communication partner, including:

 The IPv6 mobile node encapsulates the IPv4 data packet sent to the IPv4 communication partner into an IPv6 data packet by using the IPv6 reverse tunnel, and transmits the IPv4 data packet to the IPv6 home agent; wherein, the destination address of the IPv4 data packet is an IPv4 communication partner, and the source The address is an IPv4 home address of the IPv6 mobile node; the destination address of the IPv6 data packet is an IPv6 home agent, and the source address is an IPv6 care-of address of the IPv6 mobile node;

 Decapsulating the IPv6 data packet by the IPv6 home agent, and restoring the IPv4 data packet sent to the IPv4 communication partner;

 The IPv6 home agent sends the IPv4 data packet to the IPv4 communication partner when it confirms that the IPv4 home address has been proxied.

 The method according to claim 9, wherein the sending the IPv4 data packet to the IPv4 communication partner comprises:

 The IPv6 home agent searches for and obtains the IPv4 hometown corresponding to the IPv4 home address in the information recorded by the process of registering the IPv4 home node to the IPv4 home agent according to the source address information of the IPv4 home address carried by the IPv4 data packet. Proxy address

 The IPv4 data packet is encapsulated and sent to the corresponding IPv4 home agent through an IPv4 reverse tunnel whose destination address is an IPv4 home agent and whose source address is an IPv6 home agent.

 After receiving the encapsulated IPv4 data packet, the corresponding IPv4 home agent decapsulates the data packet, restores the IPv4 data packet, and carries the IPv4 home address according to the restored IPv4 data packet. When the source address information confirms that the IP v4 home address has been proxied, the IPv4 data packet is sent to the corresponding IPv4 communication partner.

The method according to claim 10, wherein the encapsulating the IPv4 data packet and sending it to a corresponding IPv4 home agent comprises: When the IPv6 home agent supports the dual stack and has at least one IPv4 address and has an IPv4 network connection, the IPv4 data packet is encapsulated by the IPv4 reverse tunnel and sent to the corresponding IPv4 home agent; or

 When the IPv6 home agent supports the dual stack and has at least one IPv4 address and does not have an IPv4 network connection, the IPv4 data packet is encapsulated by the IPv4 reverse tunnel, and then encapsulated by an IPv4 Over IPv6 tunnel or a general routing. The tunnel is sent to the corresponding IPv4 home agent.

 12. The method according to any one of claims 1 to 7, wherein the IPv6 home agent cooperates with the IPv4 home agent to forward data between the IPv6 mobile node and the IPv4 communication partner, including:

 The IPv4 home agent intercepts an IPv4 data packet sent from the IPv4 communication partner to the IPv6 mobile node, and encapsulates the IPv4 data packet into a corresponding IPv4 data packet, and then sends the IPv4 data packet to the IPv4 home address corresponding to the IPv6 mobile node. IPv6 home agent;

 After the IPv6 home agent de-encapsulates the received IPv4 data packet, the IPv4 data packet sent to the IPv6 mobile node is restored, and the IPv4 data packet of the restored IPv4 data packet is the destination address of the IPv4 home address, and the IPv4 data packet is used. The packet is sent to the IPv6 mobile node.

 The method according to claim 12, wherein the sending the IPv4 data packet to the IPv6 mobile node comprises:

 Searching for and obtaining an IPv6 care-of address corresponding to the IPv4 home address in the information recorded by the process of registering the IPv4 mobile node to the IPv4 home agent, according to the destination address of the IPv4 home address carried by the restored IPv4 data packet;

 And transmitting the IPv4 data packet to the IPv6 mobile node according to the obtained IPv6 care-of address.

 The method according to claim 13, wherein the sending the IPv4 data packet to the IPv6 mobile node comprises:

 Checking whether there is an IPv6 tunnel to the IPv6 care-of address. If yes, the IPv4 data packet is encapsulated into an IPv6 data packet through the IPv6 tunnel and sent to the IPv6 mobile node; otherwise, the IPv6 handover is established. The IPv6 tunnel of the address is then encapsulated into IPv6 data packets through the IPv6 tunnel and sent to the IPv6 mobile node.

The method according to claim 12, further comprising: After the IPv6 mobile node decapsulates the received IPv6 data packet, the IPv4 data packet is restored, and is uploaded to the application layer for receiving processing.

 16. A mobile IP communication system, comprising an IPv4 home agent and an IPv4 communication partner, wherein the method further comprises:

 An IPv6 mobile node, configured to provide address information to an IPv6 home agent, where the address information includes an IPv4 home address and an IPv4 home agent address, and an IPv6 home address and an IPv6 care-of address;

An IPv6 home agent, configured to obtain address information of the IPv6 mobile node; perform IPv6 mobile node registration with an IPv4 home agent corresponding to the IPv4 home agent address; and forward an IPv6 mobile node to an IPv4 communication partner with an IPv4 home agent data.

 17. An IPv6 home agent, characterized by comprising:

 The address information obtaining unit is configured to obtain an IPv4 home address and an IPv4 home agent address of the IPv6 mobile node, and an IPv6 home address and an IPv6 care-of address;

 An IPv4 registration unit, configured to register an IPv6 mobile node with an IPv4 home agent corresponding to the IPv4 home agent address;

 The data forwarding unit is configured to cooperate with the IPv4 home agent to forward data between the IPv6 mobile node and the IPv4 communication partner.

 The IPv6 home agent according to claim 17, wherein the address information obtaining unit is a binding update message parsing unit, configured to obtain an IPv6 home address and an IPv6 handoff from a binding update message from an IPv6 mobile node. Address, as well as IPv4 home address and IPv4 home agent address.

 The IPv6 home agent according to claim 17, wherein the IPv4 registration unit comprises:

 An IPv4 registration request message constructing unit is configured to use an IPv4 home agent address as a destination address of the registration request message, and construct an IPv4 registration request message by using an IPv4 home agent IPv4 address as a source address of the registration request message;

 The IPv4 registration request message sending unit is configured to send the constructed IPv4 registration request message to the IPv4 home agent instead of the IPv6 mobile node.

The IPv6 home agent according to claim 17, wherein the data forwarding unit comprises: An IPv6 packet decapsulation unit, configured to decapsulate an IPv6 data packet from an IPv6 mobile node, and restore an IPv4 data packet sent to the IPv4 communication partner;

 An IPv4 data packet encapsulating unit, configured to encapsulate the IPv4 data packet by using an IPv4 reverse tunnel whose destination address is an IPv4 home agent and an IPv6 home agent address;

 An IPv4 data packet sending unit is configured to send the encapsulated IPv4 data packet to a corresponding IPv4 home agent.

 The IPv6 home agent according to claim 17, wherein the data forwarding unit comprises:

 The IPv4 data packet decapsulation unit is configured to: after decapsulating the IPv4 data packet from the IPv4 home agent, to restore the IPv4 data packet sent to the IPv6 mobile node;

 An IPv6 data packet encapsulating unit, configured to encapsulate the IPv4 data packet into an IPv6 data packet by using an IPv6 tunnel to an IPv6 care-of address;

 An IPv6 packet sending unit is configured to send the encapsulated IPv6 data packet to the IPv6 mobile node.