KR20060035301A - System and method for mobile vpn service over nai in the heterogeneous network - Google Patents

Abstract

The present invention allows a mobile node to access a mobile node connected through various access networks in a heterogeneous network as well as an internal service network to which the mobile node is subscribed, as well as an external service network through roaming to use the service. The present invention relates to a system and method for mobile virtual private network (VPN) based mobile network access identifier (NAI) in a heterogeneous network.

The present invention provides a mobile VPN service in a heterogeneous network by using NAI service profile information for a mobile node using a mobile VPN service, so that the mobile node user of the internal service network to which the mobile node user subscribes together with the Internet service. In addition to the service, various services provided by the service provider of the external service network to which the user subscribes can be used.

Mobile node, mobile VPN service, access network, roaming client, roaming server, authentication, IP address assignment, service provider

Description

System and Method for Mobile VPN Service Over NAI In the Heterogeneous Network}

1 is a view schematically showing a conventional mobile VPN service network.

2 is a diagram illustrating a mobile VPN service network according to the present invention.

3 is a diagram illustrating an NAI service profile managed by a roaming server in the present invention.

4A, 4B, and 4C are diagrams for explaining an NAI-based mobile VPN service operation in a heterogeneous network according to the present invention.

5 is a diagram illustrating a NAI extended field analysis and processing procedure by a roaming server in the present invention.

Explanation of symbols on the main parts of the drawings

10: roaming client 15: access network

20: Roaming Server 21: AAA Server

22: DHCP server 25: Internal service network (service provider)

30: external service network (service provider)

The present invention relates to a virtual private network (VPN) service for a mobile node, and more particularly to roaming (not only an internal service network to which a mobile node user subscribes to a mobile node connected through various access networks in a heterogeneous network). The present invention relates to a mobile VPN service system and method based on NAI (Network Access Identifier) in a heterogeneous network that enables access to an external service network through roaming).

The conventional mobile VPN service is limited to a service using resources and contents of a VPN access network. However, when the NAI-based VPN service device is used, the mobile VPN service serves as a branch point for accessing not only the internal service but also other services. That is, it serves as an access network for accessing another service network.

Recently, with the rapid development of the information and communication field, the Internet and mobile communication are interlocked. As a result, the mobile node can be connected to the Internet as a mobile node as well as an environment where the Internet can be used anytime and anywhere. Provides an environment that can support mobility while connected to the Internet.

However, as a result of the interworking of the Internet and the mobile communication, many problems have been raised due to the Internet protocol that does not support the mobility of the mobile node, and the concept of the mobile IP has been proposed to solve this problem.

In order to provide such mobile IP service, the mobile node has two IP addresses in order to maintain connection of the transport layer and correct routing of the IP layer. One address is a home address and a general IP address. Similarly, it is fixed and used for the purpose of distinguishing TCP connections, and the other address is changed to a new connection point by a care-of address (COA), and the actual location of a mobile node such as a PDA or a notebook computer. This is an address that reflects.

In addition, there is a growing demand for equipment that provides a unified path to access various services networks as well as Internet services to mobile nodes connected through various access networks in heterogeneous networks based on mobile IP. Mobile VPN (Virtual Private Network) service network structure is as shown in Figure 1, the mobile node uses the mobile IP protocol for roaming (heterogeneous network) roaming between heterogeneous networks, the information set in the mobile node Therefore, it is possible to access the home server of the home network through the access network in which it is located, that is, WLAN network, WiBro network, CDMA network, WCDMA network, and so on. Various services provided by the internal service provider may be used.

In other words, if a mobile node attempts to access a packet to an access network such as WLAN network, WiBro network, CDMA network, WCDMA network, WLAN network AP, WiBro network ACR, CDMA network PDSN, WCDMA network GGSN IP address By assigning to, the mobile node sets the IP address assigned from its access network to the COA.

In addition, the mobile node that has set up the COA transmits a Registration Request message through the access network to access the home server to which the COA is subscribed. Accordingly, the home server interworks with the AAA (Authentication, Authorization and Accounting) server. The mobile station performs an authentication procedure for the mobile node and allocates a predetermined IP address in association with an IP pool or a DHCP (Dynamic Host Configuration Protocol) server.

Thereafter, the home server transmits a registration response message including the IP address previously allocated to the mobile node through the access network, and the mobile node sets the IP address included in the registration response message as the home address to perform a series of location registration. In this way, the mobile node connected to the home server can use the Internet connection provided by the home network, that is, the service network, or various services provided by the internal service provider.

However, the above-described conventional VPN service based on mobile IP has a disadvantage in that it is able to access its own home network according to the information set in the mobile node, but not to an external service town. Notwithstanding the various needs of the service subscriber, only the simple Internet access provided by the service subscriber's home network or the service provided by the internal service provider can be used, and the access to the external service network and various services provided by the external service network are available. There was a problem that can not use.

An object of the present invention is to provide a mobile VPN service in a heterogeneous network through roaming using NAI service profile information for a mobile node using a mobile VPN service.

Another object of the present invention is to provide a mobile VPN service in a heterogeneous network to a mobile node, whereby the mobile node user joins the Internet service and the external service to which the mobile node user subscribes as well as the service of the internal service network to which the mobile node user subscribes. It is to make various services provided by the service provider of the network available.

A feature of the present invention for solving the above object is a mobile node that accesses a service network through a connection network based on mobile IP to use a series of services, and sets an IP address allocated from the access network to a COA. And inserts additional information for accessing a predetermined service network into the NAI extension field in the registration request message and transmits it through the access network. When a registration response message is received, an IP address included in the home address field of the registration response message. A roaming client that extracts information and sets it as its home address; Authentication information used to set the address of the AAA server for authentication and billing processing, IP allocation type information used to set the IP address allocation method, and gateway used to set the IP address of the service provider serving as a service portal. A NAI service profile having IP address information; A server serving as a branch point for accessing an external service network as well as an internal service network in which it is located, and searching for the NAI service profile by parsing service access request information included in an NAI extension field of a registration request message received from the roaming client. A roaming server that performs authentication and IP address assignment procedures according to the NAI service profile information obtained as a result of the search, and inserts the allocated IP address information into the home address field of the registration response message and transmits the roaming client to the roaming client. It is to provide a N-based mobile VNP service system in heterogeneous networks, including.

Here, the additional information inserted into the NAI extension field is service access request information for a service network to be accessed through a roaming server, and the user name, service network identification information and subscribed service network information in a REALM format. It is characterized by the created information.

The NAI service profile is an information table managed by a roaming server, and includes a NAI service profile name for identifying a service provider of each service network connected through the roaming server, a description of the NAI service profile, Gateway IP address, which is a service provider IP address used to access an external service network from the roaming server, a maximum number of sessions that can access a service network, a maximum number of dynamically allocated IP addresses, and AAA for authentication and billing. Server IP address, AAA server key value for authentication between service network where roaming server is located and equipment of external service network, IP address of DHCP server, IP address assignment method, and dynamically assigned starting IP address And an information field on a mask length of a dynamically allocated start IP address.

In addition, the roaming server analyzes the service access request information parsed from the NAI extension field, extracts service network identification information to be accessed, and searches for and authenticates NAI service profile information having the NAI service profile name corresponding to the service network. And performing an IP address assignment procedure, checking the AAA server IP address information set in the NAI service profile, performing an authentication procedure by interworking with an AAA server of an internal or external service network having the AAA server IP address, and assigning an IP address. The method information may be checked to allocate an IP address in association with an IP pool or DHCP.

In another aspect of the present invention, a roaming client having an IP address assigned from its access network located as a COA inserts additional information for accessing a predetermined service network into a NAI extension field in a registration request message and transmits the additional information to a roaming server. Process; Parsing, by the roaming server, service access request information, which is additional information included in an NAI extension field of a registration request message, and searching for corresponding NAI service profile information; Checking the AAA server IP address information set in the retrieved NAI service profile and performing an authentication procedure in association with an AAA server having the IP address; Checking an IP address allocation method set in the NAI service profile after performing the authentication procedure and allocating an IP address in association with an IP pool or DHCP; By inserting the above-mentioned IP address into the home address field of the registration response message and transmitting it to the roaming client, the roaming client sets the IP address information included in the home address field of the registration response message as its home address. The present invention provides a method of NB-based mobile VPI service in a heterogeneous network including accessing a service provider and using the service.

The roaming client transmits a registration request message to a roaming server. The home address field in the registration request message is set to an initial value of '0', and a roaming server is connected to a NAI extension field to provide a service. And inserting the service connection request information, which is additional information that can be connected to the service provider, in a REALM format.

In the heterogeneous network described above, the NAI-based mobile VPI service method includes, when a registration request message transmitted from a roaming client is received to the roaming server, NAI extension in which predetermined service access request information is recorded in the registration request message. Checking whether the field exists; And parsing the NAI value, which is the service access request information recorded in the registration request message, to determine whether the NAI service profile corresponding to the NAI value exists.

In addition, in the aforementioned heterogeneous network, the NAI-based mobile VN service method checks the AAA server IP address information set in the NAI service profile, and when the AAA server IP address is set to an initial value '0'. The method may further include performing an IP allocation procedure without performing an authentication procedure.

If the AAA server IP address set in the NAI service profile is the AAA server IP address of the internal service network to which the roaming client is subscribed, the authentication procedure may be performed using the AAA server and the RADIUS transport protocol of the internal service network having the IP address. Characterized in that to perform a series of authentication procedures by interworking, and in performing the authentication procedure, when a roaming client user wants to use a service of an external service network, an internal service network that performs an authentication procedure by interworking with the roaming server. The AAA server of the AAI server using the AAA server key value set in the service profile, characterized in that the authentication process with the AAA server of the external service network, the AAA server IP address set in the NAI service profile is AAA server of the external service network In case of IP address, roaming server uses infrastructure of internal service network. Rather directly with AAA server in the service network to the external it is characterized in that for performing the authentication process.

The process of allocating the IP address may include allocating one IP address from an IP address band owned by the roaming server when the IP address allocation method set in the NAI service profile is an IP pool. If the set IP address allocation method is DHCP interworking, it checks the DHCP server IP address information of the NAI service profile, accesses the DHCP address having the IP address, and allocates a series of IP addresses in cooperation with the DHCP server. It is done.

In addition, in allocating an IP address in conjunction with the DHCP server, the IP address allocation method set in the NAI service profile is DHCP interworking, and if the DHCP server IP address is a DHCP server IP address of an internal service network, the IP address has the IP address. It is characterized by assigning an IP address by interworking with a DHCP server of an internal service network, and roaming when the IP address assignment method set in the NAI service profile is DHCP interworking and the DHCP server IP address is a DHCP server IP address of an external service network. It is characterized in that the server performs the authentication procedure by interworking with the DHCP server of the external service network directly without using the infrastructure of the internal service network.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the present invention, in providing a mobile VPN service in a heterogeneous network, additional information for accessing an external service network through roaming between heterogeneous networks in a NAI (Network Access Identifier) extension field in a registration request message, which is a mobile IP message, is provided in a REALM format. By setting the mobile node, the mobile node can access the external service network through the roaming server of the service network to which the mobile node is subscribed, and use various services provided by the external service provider. The structure of the mobile VPN service network is shown in the accompanying drawings. Same as 2.

That is, in the heterogeneous network according to the present invention, as shown in FIG. 2, the NAI-based mobile VPN service network includes a mobile node, that is, a roaming client, connected to a network (WLAN network, WiBro network, CDMA network, WCDMA network, etc.). Roaming Server (Roaming Server) and through the roaming server to the service provider of the external service network has a structure.

A mobile node is a terminal that uses a series of services by accessing a service network through an access network based on a mobile IP service, and sets an IP address allocated from the access network as a COA, and accesses the service network to be accessed through a roaming server. The additional information that can be accessed is included in the NAI extension field of the registration request message and transmitted, and the IP address information included in the home address field of the registration response message received from the roaming server is extracted and set as its own home address.

Here, the NAI extension field of the registration request message includes a series of service access request information, which is additional information for accessing the service network to which the mobile node user wants to access, in REALM format (username @ realm = username @). Address information of subscribed service network). For example, if a user called 'jane' wants to access the Internet, additional information in the form of 'jane@internet.hanro.com' (where 'hanro' refers to the service network to which the mobile node user is subscribed) in the NAI extension field. If a user named 'jane' wants to connect to the Magicn service through a roaming server of the service network to which she is subscribed, the virtual private network (VPN), that is, virtual private network, is entered in the NAI extension field. magicn.hanro.com '(where' jane 'is the user name,' Magicn 'is the external service network (i.e., external service provider) identification information you want to connect to, and' hanro.com 'is the service network you are subscribed to ( That is, the additional information is created and inserted into the address information of the virtual private network (VPN). Likewise, if a user named 'park' wants to connect to a NATE service via a roaming server of the service network he subscribes to, the additional information should be written and inserted in the format of 'park@nate.hanro.com' in the NAI extension field. do.

The roaming server plays a role of a branch point for connecting not only an internal service network but also an external service network according to a NAI service profile, that is, an access network for accessing another service network. When receiving the registration request message from the internal mobile IP module, the NAI service profile is parsed by parsing a series of service connection request information included in the NAI extension field of the registration request message, and the authentication and authentication is performed according to the NAI service profile information obtained from the search result. IP address allocation procedure is performed, and the assigned IP address information is inserted into the registration response message and transmitted to the roaming client.

Here, the NAI service profile is an information table managed by a roaming server. The NAI service profile is basically an address of an AAA server for authentication and accounting for service providers of an external service network connected by a roaming server. The authentication information used to configure the information, the IP Allocation Type information used to set the IP address allocation method (IP pool or DHCP interworking), and the IP address of the service provider serving as a service portal. Contains gateway IP address information used to configure.

The NAI service profile will be described in more detail with reference to FIG. 3. The NAI service profile name for identifying a service provider of each service network connected through a roaming server, and the NAI service profile Description, the gateway IP address, which is the service provider IP address used by the roaming server to connect to the external service network, the maximum number of sessions that can be connected to the service network, and dynamically The maximum number of assignable IP addresses (max dynamic IP address), the AAA server IP address for authentication and charging, and the AAA server for authentication between the service network where the roaming server is located and the equipment of the external service network. AAA server key, DHCP server IP address, IP address allocation type, and dynamically assigned time. IP address can contain information about the field or the like (dynamic IP address) and a beginning that is dynamically allocated IP address for the mask length (mask dynamic IP address length).

In addition, the roaming server searches for the corresponding NAI service profile information using a series of service access request information included in the NAI extension field of the registration request message, performs authentication and IP allocation procedure, and analyzes the service access request information. After extracting the service network identification information to be retrieved, the NAI service profile information having the NAI service profile name corresponding to the service network to be accessed is searched. In this case, the AAA server IP is checked by checking the AAA server IP address information of the NAI service profile. Perform authentication procedure by interworking with AAA server of internal or external service network with address, check IP address allocation method information, allocate IP address in conjunction with IP pool or DHCP, and register the assigned IP address information Insert into message's home address field to roam client over access network Song Hae gives.

Meanwhile, the NAI-based mobile VPN service processing operation in heterogeneous networks based on the above-described configuration will be described in detail with reference to FIGS. 4A, 4B, and 4C.

First, the roaming client 10, which is a mobile node, accesses a roaming server 20 through an access network based on a mobile IP service and uses a series of services, such as a WLAN network, a WiBro network, a CDMA network, and a WCDMA network. By attempting to connect a packet to (15), a predetermined IP address is assigned from the access network 15, and the IP address assigned through the packet call setup procedure with the access network 15 is set to COA (step S1). ).

After the roaming client 10 is assigned an IP address from the access network 15 and sets the COA, the roaming client 10 sends a registration request message through the access network 15 to access the roaming server 20 of the service network to which the roaming client 10 is subscribed. The home address field in the registration request message is set to '0' because its home address is not currently set, and the NAI extension field is set to set its own home address. In the REALM format, a series of service connection request information, which is an additional information that can be connected to the service network to be accessed through the roaming server 20, that is, can be connected to the service provider providing the service to be used, is transmitted. (Step S2).

Then, after receiving the registration request message transmitted from the roaming client 10, the roaming server 20 analyzes the NAI extension field of the registration request message (step S3) and manages the NAI service profile information managed by itself. Search and perform an authentication and IP address assignment procedure according to the NAI service profile information search result, wherein the roaming server 20 first receives the roaming client 10 as shown in FIG. It is checked whether the NAI extension field exists in the registration request message (step S51). If the NAI extension field exists, it is checked whether predetermined service connection request information is recorded in the NAI extension field, that is, the NAI value is recorded. If the predetermined service connection request information is recorded in the NAI extension field (step S52), the service connection request information, that is, the NAI value is parsed. By searching the service profile list NAI using the NAI value (step S53), and make sure that the service profile NAI exists corresponding to the NAI value (step S54). At this time, if there is a NAI service profile corresponding to the NAI value, the authentication and IP address allocation procedure is performed using the information set in the NAI service profile (step S56). However, the NAI extension field does not exist in the registration request message received from the roaming client 10, the service access request information is not recorded in the NAI extension field, or the NAI service profile corresponding to the NAI value parsed by the NAI extension field is present. If it does not exist, exception processing is performed (step S55). In this case, a value of "Missing NAI" is set in the code field of the registration response message and transmitted to the roaming client 10.

In addition, the roaming server 20 analyzes the NAI extension field of the registration request message, retrieves the information set in the NAI service profile, and performs an authentication and IP address assignment procedure, and the service connection recorded in the NAI extension field of the registration request message is performed. NAI service profile information corresponding to the NAI value, which is the request information, is retrieved. For example, as the roaming client user does not set the NAI extension field as shown in FIG. 4A, a default NAI value is set and transmitted in the NAI extension field. In this case, the NAI service profile information corresponding to the default NAI value (username@default.com) is retrieved, and the roaming client user uses the service provided by the service provider 30 of the external service network as shown in FIG. 4B or 4C. NAI that includes identification information for identifying the external service network (ie, external service provider) 30 in the NAI extension field. When the value (user1@svc1.vpn.com or user2@svc2.vpn.com) is set and transmitted, NAI service profile information corresponding to the NAI value of the external service network 30 is searched.

At this time, the roaming server 20 checks whether the authentication is performed by checking the AAA server IP address information for authentication and billing set in the NAI service profile (step S4), and if the AAA server IP address is '0'. If it is set, the authentication procedure is not performed (step S5). Also, as a result of checking the AAA server IP address information set in the NAI service profile, the AAA server IP address set in the NAI service profile is internal as shown in FIG. 4A. In case of AAA server IP address (192.168.1.xx) of service network, serial authentication is performed by interworking with AAA server 21 of internal service network having the IP address through RADIUS (Remote Authentication Dial-In User Service) transmission protocol. The procedure is performed (step S6). As shown in FIG. 4B, the AAA server IP address set in the NAI service profile is the AAA server IP address (192.168.1.xx) of the internal service network, and the service provided by the service provider 30 of the external service network by the roaming client user. The roaming server 20 performs an authentication procedure in association with the AAA server 21 of the internal service network having the AAA server IP address (192.168.1.xx) (step S6b). The AAA server 21 of the service network (that is, the visited network) receives the AAA server key value set in the NAI service profile as a roaming server and performs authentication with the AAA server of the external service network (ie, the home network) 30. (Step S6b-1). In addition, when the AAA server IP address set in the NAI service profile is the AAA server IP address (210.10.10.xx) of the external service network (ie, the home network) 30 as illustrated in FIG. 4C, the roaming server 20 performs the internal service. The authentication procedure is performed by interworking with the AAA server of the external service network 30 directly without using the infrastructure of the network (ie, the visited network) (step S6c).

In this way, after performing a series of authentication procedures, the IP address allocation method information set in the NAI service profile is checked (step S7), and a series of IP address allocation procedures are performed. In this case, the roaming server 20 allocates one IP address among the IP address bands owned by the server 20 (step S8), and checks the DHCP server IP address information of the NAI service profile when the IP address allocation method is DHCP interworking. After connecting to the DHCP address having the IP address, a series of IP addresses are assigned in association with the DHCP server.

That is, when the IP address allocation method set in the NAI service profile is DHCP interworking and the DHCP server IP address is the DHCP server IP address (192.168.1.yy) of the internal service network as shown in FIG. The IP address is assigned in association with the DHCP server 22 of the service network (step S9a). However, as shown in FIG. 4B or FIG. 4C, the IP address allocation method set in the NAI service profile is DHCP interworking, and the DHCP server IP address is a DHCP server IP address (ie, a home network) 30 of an external service network (210.10.0). .xx or 210.10.10.xx), the roaming server 20 performs the authentication procedure by interworking with the DHCP server of the external service network 30 directly without using the infrastructure of the internal service network (that is, the visited network). (Steps S9b, S9c).

Thereafter, when the roaming server 20 completes the above-described authentication and IP address assignment procedure, the roaming server 20 registers to the roaming client 10 through the access network 15 where the roaming client 10 that has transmitted the registration request message is located. The message is transmitted. At this time, IP address information allocated through IP pool or DHCP interworking is inserted into the home address field of the registration response message and transmitted to the roaming client 10 (step S10). The roaming client 10 ) Extracts the IP address information included in the home address field of the registration response message received from the roaming server 20, sets it as its own home address, and then connects to the service providers 25 and 30 that it wants to use. The service is used (step S11).

In addition, the embodiments according to the present invention are not limited to the above-described embodiments, and various alternatives, modifications, and changes can be made within the scope apparent to those skilled in the art.

As described above, the present invention provides a mobile VPN service in a heterogeneous network by using NAI service profile information for a mobile node using a mobile VPN service, so that the mobile node user is subscribed with the Internet service. In addition to the services of the internal service network, various services provided by the service providers of the external service network to which the user subscribes can be used.

Claims (15)

A mobile node that accesses a service network through an access network based on mobile IP to use a series of services, and sets an IP address allocated from the access network to a COA, and a predetermined service network is indicated in a NAI extension field in a registration request message. A roaming client that inserts additional information to be accessed and transmits it through the access network, and extracts IP address information included in a home address field of the registration response message and sets it as its own home address when a registration response message is received; Authentication information used to set the address of the AAA server for authentication and billing processing, IP allocation type information used to set the IP address allocation method, and gateway used to set the IP address of the service provider serving as a service portal. A NAI service profile having IP address information; A server serving as a branch point for accessing an external service network as well as an internal service network in which it is located, and searching for the NAI service profile by parsing service access request information included in an NAI extension field of a registration request message received from the roaming client. A roaming server that performs authentication and IP address assignment procedures according to the NAI service profile information obtained as a result of the search, and inserts the allocated IP address information into the home address field of the registration response message and transmits the roaming client to the roaming client. NH eye-based mobile VPI service system in a heterogeneous network comprising a. The method of claim 1, The additional information inserted into the NAI extension field is service access request information for a service network to be accessed through a roaming server, and includes information on a user name, service network identification information to be accessed, and subscribed service network information in a REALM format. NH eye-based mobile VPI service system in heterogeneous networks, characterized in that the. The method of claim 1, The NAI service profile is an information table managed by a roaming server, and includes a NAI service profile name for identifying a service provider of each service network connected through the roaming server, a description of the NAI service profile, and The gateway IP address, which is the service provider IP address used to access the external service network from the roaming server, the maximum number of sessions that can connect to the service network, the maximum number of dynamically allocated IP addresses, and the AAA server for authentication and billing. AAA server key value for authentication between the IP address, the service network where the roaming server is located, and the equipment of the external service network, the IP address of the DHCP server, the IP address allocation method, the dynamically allocated start IP address, and the dynamic In heterogeneous networks, it includes an information field on the mask length of the starting IP address assigned to NH eye-based mobile VPI service system. The method of claim 1, The roaming server analyzes the service access request information parsed from the NAI extension field, extracts the service network identification information to be accessed, searches for NAI service profile information having the NAI service profile name corresponding to the service network, and then authenticates and authenticates the IP. Performs an address assignment procedure, checks the AAA server IP address information set in the NAI service profile, performs an authentication procedure by interworking with an AAA server of an internal or external service network having the AAA server IP address, and performs an IP address allocation method information. NH eye based mobile VN service system in heterogeneous network, characterized in that to allocate an IP address in conjunction with the IP pool or DHCP. Transmitting, by a roaming client having an IP address assigned from its access network to a roaming server, inserting additional information for accessing a predetermined service network into a NAI extension field in a registration request message; Parsing, by the roaming server, service access request information, which is additional information included in an NAI extension field of a registration request message, to retrieve corresponding NAI service profile information; Checking the AAA server IP address information set in the retrieved NAI service profile and performing an authentication procedure in association with an AAA server having the IP address; Checking an IP address allocation method set in the NAI service profile after performing the authentication procedure and allocating an IP address in association with an IP pool or DHCP; By inserting the above-mentioned IP address into the home address field of the registration response message and transmitting it to the roaming client, the roaming client sets the IP address information included in the home address field of the registration response message as its home address. An AI-based mobile VP service method in a heterogeneous network comprising the step of connecting to a service provider and using the service. The method of claim 5, The roaming client may transmit a registration request message to a roaming server. The home address field of the registration request message may be set to an initial value of '0', and the roaming server may be connected to the NAI extension field to provide a service. An AI-based mobile VN service method in a heterogeneous network comprising inserting and transmitting service access request information, which is additional information that can be connected with a provider, in a REALM format. The method of claim 5, When the roaming server receives a registration request message transmitted from a roaming client, checking whether a NAI extension field including predetermined service access request information is recorded in the registration request message; Parsing the NAI value, which is the service access request information recorded in the registration request message, and checking whether the NAI service profile corresponding to the NAI value exists. Service method. The method of claim 5, And checking the AAA server IP address information set in the NAI service profile, when the AAA server IP address is set to an initial value of '0', further comprising performing an IP allocation procedure without performing an authentication procedure. NH eye-based mobile VPI service method in heterogeneous networks characterized by. The method of claim 5, If the AAA server IP address set in the NAI service profile is the AAA server IP address of the internal service network to which the roaming client is subscribed, the authentication procedure may be performed using the AAA server and the RADIUS transport protocol of the internal service network having the IP address. NH eye-based mobile VPI service method in a heterogeneous network, characterized in that to perform a series of authentication procedures in association. The method of claim 9, In performing the authentication procedure, when a roaming client user wants to use a service of an external service network, the AAA server key value set in the NAI service profile is set by the AAA server of the internal service network that performs the authentication process in association with the roaming server. An AI based mobile VP service method in a heterogeneous network, wherein the authentication procedure is performed with an AAA server of an external service network. The method of claim 5, In the process of performing the authentication, when the AAA server IP address set in the NAI service profile is the AAA server IP address of the external service network, the roaming server directly interworks with the AAA server of the external service network without using the infrastructure of the internal service network. NA based mobile VPI service method in a heterogeneous network, characterized in that to perform an authentication procedure. The method of claim 5, In the process of allocating the IP address, when the IP address allocation method set in the NAI service profile is an IP pool, the NAI in the heterogeneous network is configured to allocate one IP address among the IP address bands owned by the roaming server itself. Based mobile VPI service method. The method of claim 5, The process of allocating the IP address may include checking a DHCP server IP address information of the NAI service profile and accessing a DHCP address having the IP address when the IP address allocation method set in the NAI service profile is DHCP interworking. NH eye-based mobile VPI service method in heterogeneous networks characterized by allocating a series of IP addresses in association with a server. The method according to claim 5 or 13, In allocating an IP address by interworking with the DHCP server, if the IP address assignment method set in the NAI service profile is DHCP interworking and the DHCP server IP address is a DHCP server IP address of an internal service network, An AI-based mobile VPI service method in heterogeneous networks, wherein the IP address is allocated in association with a DHCP server of the service network. The method according to claim 5 or 13, In allocating an IP address by interworking with the DHCP server, when the IP address allocation method set in the NAI service profile is DHCP interworking, and the DHCP server IP address is a DHCP server IP address of an external service network, the roaming server of the internal service network NH eye-based mobile VPI service method in heterogeneous networks, characterized in that the authentication process is performed by interworking with a DHCP server of an external service network directly without using an infrastructure.

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