WO2009046661A1

WO2009046661A1 - A system,device and method for acquiring home address

Info

Publication number: WO2009046661A1
Application number: PCT/CN2008/072475
Authority: WO
Inventors: Sheng Jiang; Zhongqi Xia; Yangsong Xia
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2007-09-30
Filing date: 2008-09-23
Publication date: 2009-04-16
Also published as: CN101399855B; CN101399855A

Abstract

The embodiment of the present invention discloses a system, device and method for acquiring home address. Said system comprises: mobile node for sending access request to network access server when starting up in the foreign network, and sending application request for home address to DHCP server after receiving verification passing information; Network access server for sending verification information to the home network of mobile node according to the access request, and returning verification passing information to mobile node after the home network passes the verification, then receiving the home address provided by home network, transmitting the home address application request with home address to DHCP server; DHCP server for parsing home address from the home address application request, and providing home address to mobile node. With applying this invention, mobile IPv6 service can be available for the mobile node when it starts up and accesses in the foreign network.

Description

System, device and method for obtaining home address

The present invention relates to the field of Internet Protocol version 6 (IPv6) technology, and in particular, to a system, apparatus, and method for obtaining a home address. 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 (PDAs), mobile phones, in-vehicle devices, etc., the wave of mobile computing has become more and more popular. Users can connect to the Internet (Internet) through a public mobile wireless network at any location through a variety of mobile terminals. To address the needs of mobile services, mobile IP (Mobile IP) technology has been introduced at the network level. Mobile IP technology The basic principle is that the mobile node can always use the initial IP address for IP communication during the mobile process, so as to ensure that the upper layer application carried by the IP network layer maintains uninterrupted and continuable mobility.

The existing Internet Protocol version 4 (IPv4) has been exposed to gaps in address space, end-to-end IP connectivity, quality of service, network security, and mobility. The huge address space that IPv6 can provide and its many potential advantages and functions make it an important foundation for building next-generation networks. An important manifestation of the IPv6 advantage over IPv4 is the achievement of tangible mobility. IPv6-based mobile IPv6 (Mobile Internet Protocol version 6, ΜΙΡνό) offers greater flexibility in new features and new moon benefits. Mobile IPv6 can easily meet the needs of large-scale mobile users and provide a globally unique IP address for every mobile terminal running on the Internet. In this way, it can solve mobility problems between the network and access technologies on a global scale.

When a mobile node connects to its home network, the mobile node will work in the same way as other fixed nodes. If the mobile node finds that it has moved to the foreign network, it will obtain 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 simultaneously Have a home address and a care-of address. The mobile node registers its care-of address with the "Binding Update" message to the home agent. The mobile node can also notify the communication partner of this care-of address by its "binding update" message registration.

If the mobile node's communication partner does not know its care-of address, it will send the data packet to the mobile node's home network according to the mobile node's home address, and then its home agent intercepts the data packet, and then according to the mobile node's current care-of address. The tunnel mechanism is used to forward the data packets to the mobile node, and the packets sent by the mobile node to the communication partner are first sent to the home agent through the reverse tunnel, and then forwarded to the communication partner by the home agent. Because in this way, the data packets between the communication partner and the mobile node are transited through the home agent, so it is also called the "triangular routing" mode.

If the communication partner knows the mobile node's care-of address, it will use the IPv6 routing header to directly transmit the packet to the mobile node. The first destination address of the data packet is the handover address, and the second destination address is the home address, so the data packet is directly sent to the mobile node in the foreign network, without the need to transit through the home agent. In the opposite direction, the source address of the packet sent by the mobile node to the communication partner is the care-of address, and the home address is stored in the destination extension header of the packet. In this way, the data packet can also be sent to the home agent without going through the reverse tunnel, but sent directly to the communication partner. This method is called the "route optimization" approach.

In the basic IPv6 mobile protocol, only the mobile node is roamed to the foreign network in the state of being powered on, and the related communication process is defined. The process is based on the premise that the mobile node always has a home address and that the address is already registered with a home agent.

In carrying out the process of the present invention, the inventors have found that the prior art has at least the following problems:

In real-world applications, the mobile node's boot access in the foreign network is also quite common. However, the current mobile IPv6 basic protocol does not define how the mobile node obtains the home address when the foreign network is powered on. Therefore, the mobile node that is connected to the foreign network in the prior art cannot enjoy the corresponding mobile IPv6 service. Summary of the invention

The embodiment of the invention provides a system, a method, a network access server and a mobile node for obtaining a home address, so that a mobile node that is connected to the foreign network can also enjoy the mobile IPv6 service.

The system for obtaining a home address provided by the embodiment of the present invention includes a mobile node, a network access server, and a dynamic host configuration protocol (DHCP) server, where the network access server and the DHCP server are located in a foreign network to which the mobile node moves, where a mobile node, configured to send an access request to the network access server when the foreign network is powered on, and send a home address request to the DHCP server through the network access server after receiving the verification pass information returned by the network access server Request

a network access server, configured to send verification information to the mobile node's home network according to the access request, and return the verification pass information to the mobile node after receiving the home network verification, and receive the home address provided by the home network, The home address is carried in the home address request and forwarded to the DHCP server;

And a DHCP server, configured to parse the home address from the home address request request, and provide the home address to the mobile node through the network access server.

The method for obtaining a home address provided by the embodiment of the present invention includes:

The network access server located in the foreign network receives an access request sent by the mobile node when the foreign network is started;

And the network access server sends the verification information to the home network of the mobile node according to the access request, and the home network verification returns the verification pass information and the home address through the network access server;

The DHCP server located in the foreign network receives a home address request request sent by the mobile node through the network access server, where the network access server carries the home address in the home address request request and forwards the request to the DHCP server; The DHCP server located in the foreign network resolves the home address from the home address request request, and provides the home address to the mobile node through the network access server.

The network access server provided by the embodiment of the present invention includes an information processing unit and a hometown Address processing unit;

The information processing unit is configured to send verification information to the home network of the mobile node according to the access request sent by the mobile node when the foreign network where the network access server is powered on, and return the verification pass information to the mobile node after the home network verification succeeds And receiving the home address provided by the home network, and receiving the home address request request sent by the mobile node after receiving the verification pass information, forwarding the home network of the mobile node to the mobile node

The home address provided by the DHCP server according to the home address request request;

The home address processing unit is configured to carry the home address to the DHCP server of the foreign network where the mobile node is located after the home address request request.

The mobile node provided by the embodiment of the present invention includes an access request processing unit and a home address application unit, where:

An access request sending unit, configured to send an access request to a network access server located in the foreign network when the foreign network is powered on;

The home address application unit is configured to send a home address request request to the DHCP server through the network access server after receiving the verification pass information returned by the network access server, and receive the home address provided by the DHCP server;

The network access server is configured to send verification information to the mobile node's home network according to the access request, and after the home network verification passes, return the verification pass information to the mobile node and receive the home address provided by the home network, and Carrying the home address in the home address request request and forwarding it to a DHCP server located in the foreign network; the DHCP server located in the foreign network is configured to parse the home address from the home address request request, and pass the The network access server provides the home address to the home address application unit.

The mobile node that is connected to the foreign network accesses the network service using the network access server; while completing the authentication, the network access server dynamically obtains the home address assigned to the mobile node; the mobile node can then access the server through the network The DHCP server requests to obtain a home address.

Compared with the prior art, the embodiment of the invention has the following advantages:

After applying the embodiment of the present invention, the mobile node that is connected to the foreign network can also access the mobile node. The application and allocation of the home address is completed, so that the mobile node that is connected to the foreign network can also enjoy the mobile IPv6 service. DRAWINGS

1 is a schematic structural diagram of a system for obtaining a home address according to an embodiment of the present invention; FIG. 2 is a schematic flowchart of a method for obtaining a home address according to an embodiment of the present invention; FIG. 3 is a schematic structural diagram of a network access server according to an embodiment of the present invention; FIG. 4 is a schematic structural diagram of a mobile node according to an embodiment of the present invention. detailed description

The present invention will be further described in detail with reference to the accompanying drawings and specific embodiments.

In the embodiment of the present invention, the mobile node that is powered on in the foreign network accesses the network service through the network access server of the foreign network; while completing the authentication, the network access server dynamically obtains from the home network of the mobile node. The home address assigned to the mobile node; the mobile node can then apply to the DHCP server of the foreign network to obtain the home address through the network access server.

The various embodiments of the present invention are explained in more detail below.

FIG. 1 is a schematic structural diagram of a system for acquiring a home address according to an embodiment of the present invention. As shown in Fig. 1, the system includes a home network of a foreign network and a mobile node, and the mobile node 101 moves to a foreign network. Both the network access server 102 and the DHCP server 103 are located in a foreign network to which the mobile node moves, where:

The mobile node 101 generally refers to a node that can move from one link to another on the Internet and can still maintain ongoing communication, and can communicate with the mobile node 101 as long as it knows the home address of the mobile node 101. For example, the mobile node 101 may specifically be a mobile phone or a PDA or the like.

The mobile node 101 is configured to send an access request including the mobile node identifier to the network access server 102 when the foreign network is powered on, and access the server through the network after receiving the verification pass information returned by the network access server 102. 102 to the DHCP server 103 sends a home address request request. Preferably, the mobile node 101 can use the Remote Authentication Dial In User Service (RADIUS) protocol to send authentication information to the network access server 102 (specifically, the NAS Server) to request access to the network service. The RADIUS protocol is an AAA protocol that is typically used for network access, or mobile IP services. In addition, the RADIUS protocol may also be responsible for transmitting billing information between the network access server 102 and the shared billing server (not shown in Figure 1).

The network access server 102 is configured to send verification information to the home network of the mobile node 101 according to the access request, to verify the identity of the mobile node 101, and return the verification pass information and receive to the mobile node 101 after the home network verification passes. The home address of the mobile node is provided by the home network of the mobile node 101, and the home address is forwarded to the DHCP server 103 after carrying the home address request request.

The DHCP server 103 is configured to parse the home address from the home address request request, and provide the home address to the mobile node 101 through the network access server 102. The DHCP server 103 specifically uses the DHCP protocol to dynamically provide or allocate host-related configuration information. The main functions include assigning dynamic IP addresses.

The network access server 102 may directly send the verification information to the home network of the mobile node 101 for authentication, or may send the verification information to the home network of the mobile node 101 for authentication by a third-party relay. For example, the network access server 102 can relay the authentication information via a verification authorization and accounting AAA server located in the foreign network.

When the network access server 102 passes the third party relay authentication information, preferably the system further includes an AAA server 104 located in the foreign network. At this time, the network access server 102 is configured to send the verification information to the AAA server 104. The AAA server 104 is configured to send the verification information to the mobile node's home network for authentication.

Further, the AAA server 104 can also send the home address and authentication pass information to the network access server 102 by receiving the verification pass information and the home address returned by the home network after the home network verification passes.

The security of the system can be improved by relaying the verification information through the AAA server 104. The AAA transit mechanism is a management framework that provides a consistent framework for configuring the three security functions of authentication, authorization, and accounting. It is actually a management of network security.

On the home network side, as shown in FIG. 1, the home network AAA server 105 and the home network DHCP server 106 may be specifically included.

The home network AAA server 105 is configured to receive authentication information of the AAA server 104 (or the network access server 102) located in the foreign network and perform verification, and after applying the verification, apply for the home address to the home network DHCP server 106, and apply for the application. The home address to be sent is sent to the AAA server 104 (or network access server 102) located in the foreign network; the home network DHCP server 106 is configured to provide the home address to the home network AAA server 105 according to the application of the home network AAA server 105.

The preferred information interaction process of the system shown in FIG. 1 is described in detail below.

First, the mobile node 101 transmits its own access request including the mobile node identity to the network access server 102 of the foreign network using the remote user dialing authentication protocol; the network access server 102 determines the mobile according to the node identifier in the access request. The node needs to obtain the home address, and sends the verification information to the local AAA server 104, where the verification message includes the home address request field; the local AAA server 104 forwards the verification message to the home AAA server 105, and the verification message includes the home address request field; The home AAA server 105 verifies the user authentication information and, after passing the user authentication information, requests the home DHCP server 106 for an available home address.

Then, the home DHCP server 106 returns a home address to the home AAA server 105; the home AAA server 105 returns a verification pass message to the local AAA server 104, the verification pass message containing a field carrying the home address; the local AAA server 104 to the network access server 102 returns a verification pass message, the verification pass message includes a field carrying a home address; the network access server returns a verification pass message to the mobile node, permitting the mobile node to access by itself, and simultaneously cache the home address corresponding to the mobile node.

The mobile node 101 applies to the local DHCP server 103 for obtaining the home address through the network access server 102; the network access server 102 forwards the DHCP request. When the information is added, a field carrying the home address corresponding to the mobile node is added, and the DHCP server 103 responds to the mobile node 101 with the home address through the network access server 102, so that the mobile node 101 can obtain the home address and enjoy the mobile IPv6 correspondingly. service.

The embodiment of the invention further discloses a method for obtaining a home address, which specifically includes: a network access server located in a foreign network receiving an access request sent by a mobile node when the foreign network is powered on; the network access server according to the The access request sends verification information to the mobile node's home network, and the home network verification returns the verification pass information and the home address through the network access server; the DHCP server located in the foreign network receives the mobile node to send through the network access server. a home address request request, wherein the network access server forwards the home address to the DHCP server in the home address request request; the DHCP server parses the home address from the home address request request, and passes the The network access server provides the home address to the mobile node.

Based on the above method, the embodiment of the present invention may have various specific implementation manners. 2 is a schematic flow chart of a method for obtaining a home address according to an embodiment of the present invention.

As shown in FIG. 2, the method includes two parts, an access authentication part and a DHCP address discovery part.

For the access verification part, the specific includes:

Step S101 to step S102: the mobile node (MN) connects to the network access server (NAS) through a Layer 2 link protocol (such as the Radius protocol), and sends an access request including the identity of the mobile node to the NAS; The incoming request sends authentication information to the AAA server of the local network, and the mobile node identity is included in the verification information.

Step S103 ~ Step S104: The AAA server communicates with the AAA server of the mobile node's home network, and the AAA server of the home network determines whether the mobile node is legal according to the mobile node identity to verify the mobile node; AAA server authentication of the home network When passing, the AAA server of the home network requests the home address (HoA request;) from the DHCP server of the home network.

Step S105 ~ Step S106: The DHCP server of the home network sends a home address response (HoA response) to the AAA server of the home network; AAA service of the home network The device returns a verification response to the AAA server of the foreign network where the mobile node is located, and returns the home address in the verification response.

Step S107 to step S108: After receiving the verification response, the NAS of the foreign network caches the home address of the mobile node, sends a verification response to the mobile node, and informs the mobile node to pass the verification.

At this point, the access verification section is completed, and then the DHCP address discovery section is sequentially executed.

The DHCP address discovery process specifically includes:

Step S201 ~ Step S202: The mobile node sends a DHCP request message to the foreign NAS, requesting to obtain a home address, and the NAS inserts a home address option into the DHCP request to form a DHCP relay request relay message (DHCP request in relay), and the DHCP The request message is forwarded to the local DHCP server.

For example: You can add the HoA information sub-option to the MIP6 Relay Agent option to use the HoA information sub-option to insert the home address option.

The format of the existing OPTION-MIP6-RELAY is as follows:

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

- + - - + - -+-+-+-+- -+-+-+-+-+-+-+-+-+-+- + - - + - - + - - + - - + - - +■ -+-+-+-+-+-+- - + - - + - - + - OPTION_ _MIP6- RELAY option-len

- + - - + - -+-+-+-+- -+-+-+-+-+-+-+-+-+-+- + - - + - - + - - + - - + - - +■ -+-+-+-+-+-+- - + - - + - - + - sub-options

The HoA sub-option can be added to the sub-options of the above format. The new HoA sub-option format can be as follows:

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 sub -hoa- code | sub-opt-len | reserved |

You can insert your hometown in the Home Address Information of the new HoA sub-option. Obviously, it is also possible to develop a related protocol or change the format of other fields to insert a home address option, which is not limited by the embodiment of the present invention.

Steps S203 to S204: After receiving the DHCP relay request message, the DHCP server of the foreign network returns the home address assigned to the mobile node to the mobile node through the NAS.

You can add the HoA suboption in the existing Home Network Information Option to insert the home address option assigned to the mobile node.

Ratio ^: The existing Home Network Information Option format:

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

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

1 OPTION— _MIP6-HNINF option- len 1

1 id- type reserved 1

+ - - + - - + -+-+-+-+- -+-+-+-+-+-+-+-+-+-+ + sub-options

+ - - + - - + -+-+-+-+- -+-+-+-+-+-+-+-+-+-+- + - - + - - + - - + - -+ -+-+-+ - + - + - - + - - + - - + - - + - - + - - + You can add HoA sub-options in the sub-options of the above format, the new HoA sub-option format as follows:

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 sub -hoa- code | sub-hoa-len | V | reserved | .

Home Address Information

The Home Address Information can carry a specific home address.

It is obvious that the home address option can be inserted by the related protocol or the format of the other fields. The embodiment of the present invention does not limit this.

The embodiment of the invention also proposes a network access server.

FIG. 3 is a schematic structural diagram of a network access server according to an embodiment of the present invention. As shown in FIG. 3, the network access server includes an information processing unit 301 and a home address processing unit 302:

The information processing unit 301 is configured to send, according to an access request sent by the mobile node when the foreign network where the network access server is powered on, to the mobile node's home network. Verifying information; receiving verification pass information and home address from the home network, storing the home address, and transmitting the verification pass information to the mobile node;

The home address processing unit 302 is configured to receive a home address request request from the mobile node, and send the home address to the DHCP server of the foreign network where the mobile node is located in the home address request request, so that the The DHCP server parses the home address from the home address request request; and forwards the home address from the DHCP server to the mobile node.

It can be seen that the access server of the above structure can be specifically applied to the network to which the mobile node moves to help the mobile node apply for the home address.

The embodiment of the invention also proposes a mobile node.

FIG. 4 is a schematic structural diagram of a mobile node according to an embodiment of the present invention.

As shown in FIG. 4, the mobile node includes an access request sending unit 401 and a home address requesting unit 402, where:

The access request sending unit 401 is configured to send an access request to the network access server located in the foreign network when the mobile node is powered on, where the access request includes a mobile node identifier;

The home address application unit 402 is configured to send, by the network access server, a home address request request to the foreign network DHCP server where the mobile node is located after receiving the verification pass information returned by the network access server, and receive the home address request request by the mobile node. The home network address provided by the foreign network DHCP server through the network access server;

The network access server is configured to send verification information to the home network of the mobile node according to the access request, and after receiving the home network verification, the verification pass information returned by the home network and the home address of the mobile node are sent to the The mobile node returns the verification pass information; and after receiving the home address request request sent by the mobile node, the home address is carried to the DHCP server of the foreign network after the home address request request; the DHCP server of the foreign network uses The home address is parsed from the home address application request, and the home address is provided to the home address application unit through the network access server.

In summary, in the embodiment of the present invention, the mobile node that is connected to the network in the foreign network is connected. The remote user dial-up authentication system is used to access the network service; while the authentication is completed, the network access server dynamically obtains the home address assigned to the mobile node; the mobile node can then apply to the DHCP server of the foreign network through the network access server. Home address. Therefore, after applying the embodiment of the present invention, the mobile node that is connected to the foreign network can also complete the application and allocation of the home address, so that the mobile node that is connected to the foreign network can also enjoy the mobile IPv6 service.

In addition, the embodiment of the present invention also utilizes the existing widely deployed mature technology to solve the allocation process of the home address, and thus is also relatively simple to implement.

Through the description of the above embodiments, those skilled in the art can clearly understand that the present invention can be implemented by hardware or by software plus necessary general hardware platform. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which may be stored in a non-volatile storage medium (which may be a CD-ROM, a USB flash drive, a mobile hard disk, etc.), including several The instructions are for causing a computer device (which may be a personal computer, server, or network device, etc.) to perform the methods described in various embodiments of the present invention.

In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

Rights request

A system for obtaining a home address, the system comprising: a mobile node, a network access server, and a dynamic host configuration protocol DHCP server, wherein the network access server and the DHCP server are both located at the mobile node to move to Field network, where:

a mobile node, configured to send an access request to the network access server when the network is powered on, and send a home address to the network access server after receiving the verification pass information returned by the network access server Application request;

a network access server, configured to send verification information to the mobile node's home network according to the access request, and return the verification pass information to the mobile node after verifying the home network; receive the home address provided by the home network; When the home address request request sent by the mobile node is sent, the home address is carried in the home address request request, and the home address request request is forwarded to the DHCP server;

And a DHCP server, configured to parse the home address from the home address request request, and provide the home address to the mobile node by using the network access server.

2. The system for obtaining a home address according to claim 1, wherein said system further comprises a verification authorization and accounting AAA server located in said foreign network;

The network access server is configured to send the verification information to the AAA server;

The AAA server is configured to send the verification information to a home network of the mobile node for authentication.

The system for obtaining a home address according to claim 2, wherein the AAA server is further configured to receive the insurance pass information and the home address returned by the home network after the home network verification is passed. The home address and the risk certificate are sent to the network access server by information.

4. The system for obtaining a home address according to claim 3, wherein the home network comprises a home network AAA server and a home network DHCP server, Medium,

The home network AAA server is configured to receive the verification information sent by the AAA server located in the foreign network and perform verification, and after verifying, apply for the home address to the home network DHCP server, and send the applied home address to the home address. Said AAA server located in the foreign network;

The home network DHCP server is configured to provide the home address of the mobile node to the home network AAA server according to the application of the home network AAA server.

A method for obtaining a home address, the method comprising: the mobile node transmitting an access request including a mobile node identifier to a network access server of the foreign network when the foreign network is powered on;

The mobile node receives authentication pass information from the network access server; the mobile node sends a home address request request to the network access server; the mobile node receives a foreign network through the network access server

The home address of the DHCP server.

The method for obtaining a home address according to claim 5, wherein before the mobile node receives the verification pass information from the network access server, the method further includes:

Sending, by the network access server, verification information to a home network of the mobile node, causing the home network to verify the mobile node; receiving a horse pass information from the home network and a hometown of the mobile node address.

The method for obtaining a home address according to claim 6, wherein the network access server sends verification information to a home network of the mobile node, so that the home network performs verification on the mobile node; Receiving the verification pass information from the home network and the home address of the mobile node includes:

The network access server sends the verification information to an AAA server located in the foreign network;

The AAA server of the foreign network sends the verification information to the home network AAA server of the mobile node for authentication;

The mobile node's home network AAA server is verified to pass through the home network The DHCP server of the network applies for the home address, and sends the applied home address and the verification pass information to the AAA server located in the foreign network;

The AAA server located in the foreign network transmits the verification through the information and the home address to the network access server.

The method for obtaining a home address according to claim 6, wherein the receiving, by the mobile node, the home address of the DHCP server from the foreign network through the network access server comprises:

Receiving, by the network access server, a home address request request sent by the mobile node; carrying the home address of the mobile node in the home address request request, and sending the request to the DHCP server, so that the foreign network DHCP server is from the Resolving the home address in the home address request request, and forwarding the home address from the foreign network DHCP server to the mobile node;

The mobile node receives the home address.

A network access server, wherein the network access server comprises an information processing unit and a home address processing unit,

An information processing unit, configured to send, according to an access request sent by the mobile node when the foreign network of the network access server is powered on, send verification information to the mobile node's home network; receive the verification pass information and the hometown from the home network An address, the verification pass information is sent to the mobile node;

a home address processing unit, configured to receive a home address request request from the mobile node, and send the home address to the DHCP server of the foreign network where the mobile node is located in the home address request request, so that the DHCP The server parses the home address from the home address request request, and forwards the home address from the DHCP server to the mobile node.

A mobile node, comprising: an access request sending unit and a home address requesting unit, wherein:

An access request sending unit, configured to send an access request to a network access server located in the foreign network when the foreign network is powered on, where the access request includes a mobile node identifier; and a home address application unit is used to receive the Said verification returned by the network access server Sending a home address request request to the DHCP server located in the foreign network through the network access server through the information, and receiving, by the network access server, by the network access server

The home address provided by the DHCP server.