WO2005062631A1

WO2005062631A1 - Method of redirecting packet data gateway in wireless local area network

Info

Publication number: WO2005062631A1
Application number: PCT/CN2004/001214
Authority: WO
Inventors: Wenlin Zhang; Yingxin Huang
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2003-12-24
Filing date: 2004-10-26
Publication date: 2005-07-07
Also published as: CN100337444C; CN1633090A

Abstract

The present invention provides a method of redirecting packet data gateway (PDG) in wireless local area network. Using the present invention, when user terminal fails to access the PDG, the PDG which has received the application of user terminal return failure message including IP address of PDG which can provide service for application user to user terminal. After receiving the message , the user terminal performs redirection using the IP address which the message provided, requests establishing tunnel link to new PDG Thus , user terminal can directly redirect to PDG which can provide service, avoiding the process that user terminal accesses DNS and redirects to home network to select PDG At the same time , user terminal can definitely know which PDG can provide service with present invention, therefore reducing the number of connecting failure , and optimizing the utilization of network source.

Description

Method for redirecting packet data gateway in wireless local area network

Technical field

The present invention relates to the field of wireless access technology, and particularly to a method for redirecting a packet data gateway (PDG) in a wireless local area network. Background of the invention

With the development of society, users have higher and higher requirements for wireless access rates. Since wireless local area networks (WLAN, Wireless Local Area Network) can provide high-speed wireless data access in a small range, it is widely used. Wireless local area network includes a variety of different technologies. One of the more widely used technical standards is IEEE 802.11b. It uses the 2.4GHz frequency band and the highest data transmission rate is 11Mbps. IEEE 802.11g and Bluetooth are also used in this frequency band. Technology, among them, the highest data transmission rate of 802.11g can reach 54Mbps. Other wireless LAN technologies, such as IEEE 802.11a and ETSI BRAN Hiperlan2, use the 5GHz band, and the highest transmission rate can reach 54Mbps.

Although there are many different WLAN wireless access technologies, most WLANs use Internet Protocol (IP) packet data packets for data transmission. For a wireless IP network, the specific WLAN access technology it uses is generally transparent to the upper-layer IP. Its basic structure is to use an access point (AP) to complete the wireless access of the user terminal. An IP transmission network composed of connected devices is used for data transmission.

With the rise and development of WLAN technology, WLAN and various wireless mobile communication networks, such as: Global System for Mobile Communications (GSM), Code Division Multiple Access (CDMA) system, Wideband Code Division Multiple Access (WCDMA) system, Time Division Duplex -Interworking of synchronous code division multiple access (TD-SCDMA) system and CDMA2000 system is becoming the focus of current research. In the 3rd Generation Partnership Project (3GPP) standardization organization, user terminals can both access the network through WLAN It is connected to the Internet (Internet) and the corporate intranet (Intranet), and can also be connected to the home network of the 3GPP system or the access network of the 3GPP system via a WLAN access network.

Figure 1 shows the schematic diagram of the networking structure between the WLAN system and the 3GPP system in the case of roaming. During roaming access, WLAN user terminals are connected to the 3GPP access network via the WLAN access network. As some entities in the 3GPP access network are connected to corresponding entities in the 3GPP home network, for example: 3 GPP access network 3 GPP Authentication, Authorization and Accounting (AAA) proxy and 3GPP Authentication, Authorization and Accounting (AAA) server in the 3GPP home network; Wireless Local Area Network Access Gateway (WAG) in the 3GPP access network and the packet gateway in the 3GPP home network (PDG, Packet Data Gateway) and so on, so that the WLAN user terminal accesses the 3GPP home network. The shaded part in the figure is the 3GPP packet switching (PS) domain service, that is, the Scenario3 service in the 3GPP network.

Figure 2 shows a schematic diagram of the networking structure of the WLAN system and the 3GPP system in the non-roaming situation. When a WLAN user terminal accesses locally, it is directly connected to the 3GPP home network via the WLAN access network. The shaded part in the figure is the 3GPP packet switching (PS) domain service, that is, the Scenario3 service in the 3GPP home network.

As shown in Figures 1 and 2, in the 3GPP system, it mainly includes a Home Subscriber Subscriber Server (HSS) / Home Location Register (HLR), a 3GPP AAA server, a 3GPP AAA proxy, a WAG, a packet data gateway, and a charging gateway (CGw ) / Charging Information Collection System (CCF) and Online Charging System (OCS). The user terminal, the WLAN access network, and all entities of the 3GPP system together constitute a 3GPP-WLAN interactive network. The 3GPP-WLAN interactive network can be used as a wireless local area network service system. Among them, the 3GPP AAA server is responsible for user authentication, authorization, and charging, and collects and transmits the charging information sent by the WLAN access network to the charging system. The packet data gateway (PDG) is responsible for accessing user data from the WLAN. The network transmits to the 3GPP network or other packet networks; the charging system mainly receives and records user charging information from the network, and OCS indicates the network periodicity according to the online charging user's fee situation To transmit online expense information, and perform statistics and control.

In a non-roaming situation, when a WLAN user terminal wants to directly access the Internet / Intranet, after the user terminal completes access authentication and authorization through the WLAN access network and the AAA server (AS), the user terminal directly accesses the Internet / Intranet. If the WLAN user terminal also wants to access the 3GPP packet switching (PS) domain service, it can further apply for a Scenario3 service from the 3GPP home network. To apply for the Scenario3 business:

The WLAN user terminal first provides a public domain name resolution server (DNS) with a service access point name (W-APN) identifier of the service that it needs. The DNS may be a third-party public device or a public network dedicated to wireless networks. The domain name resolution device, the DNS that accepts the application resolves the corresponding IP address of one or more PDGs according to the W-APN identifier provided by the user and returns it to the WLAN terminal user. The WLAN terminal user uses one of the IP addresses obtained from the DNS to send a request to establish a tunnel connection to the PDG corresponding to the IP address. The PDG that receives the user terminal connection request contacts the AS, and the AS is responsible for performing the service identity of the user terminal. Inspection, authorization, etc. If the access authentication is successful, the PDG that received the user terminal connection request establishes a tunnel connection with the WLAN terminal user that sent the request, thereby implementing the Scenario3 service. If the access authentication is unsuccessful, the PDG that accepts the user terminal connection request will notify the WLAN user terminal.

In the case of roaming, when a WLAN user terminal wants to access the Internet / Intranet, the user terminal requests the 3GPP home network to access the Internet / Intranet through the 3GPP access network. If the user terminal wishes to apply for the Scenario3 service, the application method is:

The WLAN user terminal first provides a public DNS with the W-APN identification of the service that it needs. The DNS that accepts the application resolves the corresponding IP address of one or more PDGs according to the W-APN identification provided by the user and returns it to the WLAN terminal user. WLAN end The end user uses one of the IP addresses obtained from the DNS to send a tunnel connection request to the PDG corresponding to the IP address. The PDG receiving the user terminal connection request contacts the AS of this network, and the AS of this network and the WLAN user terminal The AS of the home network where the WLAN user terminal is located is responsible for checking and authorizing the service identity of the user terminal. If the access authentication is successful, the PDG that accepts the user terminal connection request and the WLAN that sends the request The end user establishes a tunnel connection to implement the Scenario3 service. If the access authentication is unsuccessful, the PDG that accepts the connection request from the user terminal will notify the WLAN user terminal.

After receiving the unsuccessful notification from the PDG, the WLAN user terminal will contact the DNS again to request that the DNS resolve the PDG IP address in the home network for the service to be applied for. The DNS retrieves the W-APN identifier provided by the user from the user terminal. The IP address of one or more PDGs resolved in the home network of the UE is returned to the user terminal. The WLAN terminal user again uses one of the IP addresses obtained from the DNS to send a request to establish a tunnel connection to the PDG corresponding to the IP address. The PDG that receives the user terminal connection request contacts the AS of this network, and the AS of this network contacts the AS of the home network where the WLAN user terminal is located. After authorization and other work, the PDG that accepts the user terminal connection request establishes a tunnel connection with the WLAN terminal user that sent the request, thereby implementing the Scenario3 service.

The disadvantage of the above method is that when the WLAN terminal user wishes to use a PDG that accesses the network while roaming, if the PDG notifies the WLAN user terminal that the WLAN user terminal is unsuccessful, the WLAN user terminal will contact the DNS again to resolve the PDG of the service to be accessed on the home network. IP address. In this case, the WLAN user terminal needs to contact the DNS again, which causes waste of unnecessary signaling resources, and the use of resources is not optimized. Summary of the invention

In view of this, an object of the present invention is to provide a method for redirecting a packet data gateway in a wireless local area network. When a user terminal fails to access the PDG, it can be directly redirected to a PDG that can provide services, thereby avoiding the process of contacting the DNS again. .

To achieve the above object, the technical solution of the present invention is implemented as follows:

A method for redirecting a packet data gateway in a wireless local area network. When a user terminal fails to access the packet data gateway (PDG), the method includes the following steps:

a. The PDG receiving the application from the user terminal obtains information about the IP address of the PDG that can provide services to the application user.

b. The PDG in step a returns a failure message including the obtained information to the user service application terminal;

c. After receiving the message in step b, the user terminal redirects using the IP address provided by the message, and requests a new PDG to establish a tunnel connection.

Preferably, if the user terminal access fails because the PDG received by the user terminal application cannot provide services, the method for obtaining IP address information in step a is:

The PDG obtains the IP address information of the PDG that can provide services to the user terminal from the replacement information saved by itself.

Preferably, if the user terminal access fails because the PDG received from the user terminal application cannot provide services, the method for obtaining IP address information described in step a is:

The PDG directly inquires the AAA server in the home network where the user terminal is located, or the proxy AAA server, or queries the AAA server in the home network where the user terminal is located through the proxy AAA server, to find the IP address information of the PDG where the user terminal can be served. .

Preferably, if the access of the user terminal fails because the PDG received by the user terminal cannot provide services, the method for obtaining IP address information described in step a is: The PDG queries the IP address information of the PDG that can provide services to the user terminal by executing the WLAN user terminal authentication and authorization process.

Preferably, if the user terminal fails to access the user because the AAA server in the home network where the user terminal is located does not agree with the user's use of the PDG applied for, the method for obtaining IP address information described in step a is:

The AAA server in the home network where the user terminal is located re-designates a PDG that can provide services, and provides the PDG's IP address information to the PDG that receives the user terminal application.

Preferably, if the access of the user terminal fails because the proxy AAA server does not agree with the user's use of the PDG applied for, the method for obtaining IP address information described in step a is: the proxy AAA server re-designates a capable service The PDG, and provide the PDG's IP address information to the PDG receiving the user terminal application.

Preferably, the step b fails with a layer 2 tunnel establishment protocol L2TP, or an Internet key exchange protocol IKE, or an Internet key exchange protocol version 2 IKEv2, or a GRE protocol, or a GRE protocol and an Internet key exchange protocol IKE Or IKEv2 bearer.

Applying the present invention, when the user terminal fails to access the PDG, the PDG received by the user terminal returns to the user terminal a failure message including the IP address of the PDG that can provide services to the application user. After receiving the message, the user terminal applies the message The IP address provided by the message is redirected, and a new PDG is requested to establish a tunnel connection. Therefore, the user terminal can be directly redirected to a PDG that can provide services, and the process of user terminal to DNS redirection to the home network to select a PDG is avoided. At the same time, applying the present invention enables the user terminal to clearly know which PDG can provide the service, thereby reducing the number of connection failures and optimizing the application of network resources. Brief description of the drawings

Figure 1 shows the schematic diagram of the networking structure of interworking between the WLAN system and the 3GPP system in the case of roaming;

Figure 2 shows a schematic diagram of the networking structure of the interworking between the WLAN system and the 3GPP system in a non-roaming situation;

FIG. 3 is a flowchart of a user terminal redirecting PDG to which the present invention is applied. Mode of Carrying Out the Invention

In order to make the technical solution of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The idea of the present invention is: when the user terminal fails to access the PDG, the PDG received by the user terminal obtains information about the IP address where the PDG is able to provide services to the application user, and returns to the application service user terminal including the acquired information. Failure message; the user terminal applies the IP address provided by the message to redirect, and requests a new PDG to establish a tunnel connection.

FIG. 3 is a flowchart of a user terminal redirecting PDG to which the present invention is applied.

Step 1. When a WLAN user terminal accesses the network, it must first go through a basic access authentication and authorization process. After this process, the WLAN terminal user can directly access the Internet / Intranet through the access network;

Step 2: When the WLAN user terminal wants an application to access a certain service in the 3GPP PS domain in the network, the WLAN user terminal first provides a public DNS with the W-APN identity of the service it needs. After the DNS that has accepted the application is resolved, To return the IP address of one or more PDGs to the WLAN terminal user;

Step 3a: The WLAN user terminal uses one of the IP addresses obtained from the DNS to send a request to establish a tunnel connection to the PDG corresponding to the IP address;

If the WLAN user terminal does not receive the In any response message, if it may be a PDG crash, perform step 3b, otherwise perform the corresponding operation according to the received message;

Step 3b: The WLAN user terminal selects an IP address of another PDG resolved by the DNS, and sends a request for establishing a tunnel connection to the selected IP address;

Step 4, receiving the WLAN user terminal connection request PDG to determine whether it can provide services, if it can not provide the services required by the user terminal, it may be because of suspension of service or flow control reasons, then go to step 5, otherwise go to step 7;

Step 5. The PDG that receives the WLAN user terminal connection request determines whether it has an IP address capable of providing a PDG that provides services instead of itself. If so, it directly returns to the user terminal the IP address that contains the PDG that can provide services for the application user. After the failure message, go to step 9, otherwise go to step 6;

Step 6. The PDG that receives the WLAN user terminal connection request queries the local proxy AAA server, or queries the AAA server in the home network of the WLAN user terminal through the local proxy AAA server, or directly queries the home network of the WLAN user terminal. The AAA server performs a query to obtain information of the IP address where the PDG is able to provide services to the applying user, and performs step 8;

In addition, the PDG that receives the WLAN user terminal connection request can also obtain the information of the IP address where the PDG is able to provide services to the application user by performing the WLAN user terminal authentication and authorization process, and perform step 8;

Step 7, the PDG request that received the WLAN user terminal connection request is connected to the AAA server in the home network where the WLAN user terminal is located to authenticate and authorize the WLAN user terminal, and if the authentication is passed, step 10 is performed;

If the AAA server of the home network does not allow the WLAN user terminal to use the PDG, the AAA server of the home network provides an IP address information of the PDG that can provide the service, and after transmitting the information to the PDG, perform step 8. Generally, the home network's AAA The IP address information provided by the server is usually also in the home network;

If the proxy AAA server accessing the network does not allow the WLAN user to use the PDG, the proxy AAA server accessing the network provides an IP address information of the PDG that can provide the service, and after transmitting the information to the PDG, perform step 8;

Step 8, the received WLAN user terminal connection request PDG returns to the user terminal a failure message containing the IP address of the PDG capable of providing services to the user;

Step 9. After receiving the failure message, the WLAN user terminal applies the IP address provided in the message and sends a request to establish a tunnel connection to the PDG corresponding to the IP address, and then executes step 3b;

Step 10. The PDG receives a WLAN user terminal connection request to establish a service communication tunnel with the WLAN user terminal, and provides the requested service to the user.

The above message process can be completed using the existing Internet protocol-Layer 2 Tunneling Protocol (L2TP). In the return failure message format of L2TP, there is a message field, and the message field can be added with various information as required. In the present invention, IP address information that can provide a service PDG is put into this field.

When the L2TP protocol is used as a protocol for a WLAN user terminal to access the PDG, after receiving the failure message, the WLAN user terminal must determine the result code and error code fields in the message, and it must also Further judge the information of the message field.

When the L2TP protocol is applied on the Internet, there may not be an "error code" or "message" field behind some specific "result code", but after it is applied to the WLAN wireless access network, it is required to be in the "result code" and Be sure to carry a "message" behind the "error code" to suit the special application of the wireless network.

In addition, the Internet protocol IP Security security protocol family can also be used as a tunneling protocol. The Internet key exchange protocol (IKE, Internet Key Exchange) or IKEv2 (version 2 of IKE) can also be used as the bearer protocol of the present invention, and it can be used directly. Reserved fields or Proper extensions can complete the functionality of this solution.

The Internet's GRE (Generic Routing Encapsulation) is an encapsulation protocol that supports tunneling. The IP address information of the present invention can be placed in an IP packet and then directly encapsulated in the GRE protocol to implement tunnel communication between a WLAN user terminal and a PDG. In order to provide a comparison Good security GRE protocol is best used in conjunction with IP Security protocol.

The above description is only the preferred embodiments of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention shall be included in the present invention. Within the scope of protection.

Claims

Claim

1. A method for redirecting a packet data gateway in a wireless local area network. When a user terminal fails to access the packet data gateway PDG, the method is characterized in that the method includes the following steps: a. The PDG acquisition received by the user terminal can be an application. Information of the IP address where the PDG provided by the user is located;

2. The method according to claim 1, characterized in that if the access of the user terminal fails because the PDG received from the user terminal application cannot provide services, the method for obtaining IP address information in step a is:

3. The method according to claim 1, characterized in that if the user terminal access fails because the PDG received from the user terminal application cannot provide services, the method for obtaining IP address information in step a is:

The PDG directly inquires the AAA server in the home network where the user terminal is located, or the proxy AAA server, or the AAA server in the home network where the user terminal is located through the proxy AAA server, and queries the IP address information of the PDG where the user terminal can provide services. .

4. The method according to claim 1, characterized in that, if the user terminal fails to access because the PDG received from the user terminal application cannot provide services, the method for obtaining IP address information in step a is: The PDG queries the IP address information of the PDG that can provide services to the user terminal by executing the WLAN user terminal authentication and authorization process.

5. The method according to claim 1, wherein if the user terminal access fails because the AAA server in the home network where the user terminal is located does not agree with the user's use of the PDG applied for by the user terminal, obtaining in step a The method of IP address information is:

6. The method according to claim 1, characterized in that if the user terminal access fails because the proxy AAA server does not agree that the user uses the PDG applied by him, the method for obtaining IP address information in step a is: :

The proxy AAA server re-designates a PDG capable of providing services, and provides the PDG's IP address information to the PDG that receives the user terminal application.

7. The method according to claim 1, wherein the failure message in step b is a Layer 2 Tunnel Establishment Protocol (L2TP), or an Internet Key Exchange Protocol (IKE), or a version 2 IKEv2 of the Internet Key Exchange Protocol, or GRE protocol, or GRE protocol and Internet key exchange protocol IKE or IKEv2 bearer.