WO2014032542A9

WO2014032542A9 - Method and system for setting up multiple connections

Info

Publication number: WO2014032542A9
Application number: PCT/CN2013/082101
Authority: WO
Inventors: 范亮; 尤建洁; 王怀滨; 袁博
Original assignee: 中兴通讯股份有限公司
Priority date: 2012-08-30
Filing date: 2013-08-22
Publication date: 2014-04-10
Also published as: WO2014032542A1; CN103687049A; CN103687049B

Abstract

Disclosed is a method for setting up multiple connections, including: after a BNG has received a PPP or PPPoE access request message initiated by a UE, forwarding same to a TWAG via an L2TP tunnel; and when the TWAG determines that the setup of a PDN connection for the UE is allowed according to the acquired information about an APN which the UE wants to access and the access list information about the APN, setting up the PDN connection with a PDN gateway for the UE according to the information about the APN which the UE wants to access, and sending to the UE the IP address information allocated to the UE by the PDN gateway via the BNG. Between the BNG and the TWAG, different sessions are set up on one and the same L2TP parameter connection for different UEs carrying information about the same APN; or between the BNG and the TWAG, different sessions are set up on one and the same L2TP tunnel for different UEs carrying information about different APNs. Disclosed at the same time is a system for setting up multiple connections. The present invention realizes the setup of multiple connections based on the information about an APN, and expands the application of the FMC architecture.

Description

Method and system for establishing multiple connections

The present invention relates to a multi-connection establishment technique, and more particularly to a multi-connection establishment method and system. Background technique

With the development of network technology and the increasing demand of users for business, terminals are gradually developing into multi-modality. Multimode terminals can choose to access different types of access networks to carry diverse services. Because different network connections have different characteristics and transmission capabilities, they can better meet the needs of users with multiple services. Multimode terminals enable seamless connectivity between different types of wireless access networks, such as Universal Mobile Telecommunication System (UMTS) / EDGE (Enhanced Data Rate for GSM Evolution, Enhanced Data Rate for GSM (Global System) For Mobile communication, Global Technology (LTE) / General Packet Radio Service (GPRS, General Packet Radio Service) and IEEE, Institute of Electrical and Electronics Engineer 802.11 Wireless LAN (WLAN, Wireless) Local Area Network ) connection. WLANs provide high data rates in a small range of homes and hotspots, while cellular networks offer greater flexibility and ubiquitous coverage, but at lower data rates, if combined with the advantages of both, users will Benefited from. Within the coverage of WLAN access points, multimode terminals use WLAN for data access and Voice over Internet Protocol (VoIP) applications, while also using overlapping cellular networks for voice calls or media access.

Currently, the International Standards Organization Broadband Forum (BBF, Broadband Forum) and the 3rd Generation Partnership Project (3GPP, 3rd Generation Partnership Project) are standardizing work on Fixed Network and Mobile Network Convergence (FMC). And the scenario includes the authentication, address allocation, and policy control of the 3GPP user equipment (UE, User Equipment) accessing from the BBF network through the residential gateway (RG, Residential Gateway). During the authentication process, the 3GPP UE initiates access authentication to the RG as the 802. lx client. At this time, the RG acts as the 802. lx authenticator and the remote authentication dial in user service (RADIUS, Remote Authentication Dial In User Service) to the BBF AAA. The server (Authentication Authorization Accounting, Authentication, Authorization, Accounting) initiates an authentication request. In the address request process, the address request message initiated by the 3GPP UE is via the broadband network.

Packet Data Network Gateway) requests an IP address. The S2a session is established between the BNG and the PDN-GW, and the GTP (GPRS Tunneling Protocol, GPRS (General Packet Radio Service) tunneling protocol) or the proxy mobile Internet protocol is used.

(PMIP, Proxy Mobile IP) tunnel implementation.

In the prior art, each user BNG needs to establish an S2a session with the PDN-GW. In order to support the scenario on the live network, all BNG devices need to be upgraded and have a large impact on the live network. To solve this problem, a fixed network access gateway is referenced (for example, a trusted WLAN access gateway).

(TWAG, Trusted WLAN Access Gateway)), the network structure after the introduction of TWAG is shown in Figure 1. After the introduction of the fixed network access gateway, large-scale upgrades of BNG equipment are not required, and the impact on the existing network can be minimized.

After the mobile user accesses through the fixed network, it may access different mobile service packet networks at the same time. At this time, multiple packet data network (PDN, Packet Data Network) connections are established. Under the existing architecture, the problem of how to distinguish between different PDN connections has not been resolved. Summary of the invention

In view of this, the main purpose of the present invention is to provide a method and system for establishing a multi-connection, which can establish different sessions for different UEs in the same L2TP tunnel according to the APN information that the UE wants to access. In order to achieve the above object, the technical solution of the present invention is achieved as follows:

A method for establishing multiple connections, the method comprising:

The broadband network gateway BNG receives the peer-to-peer protocol PPP or the Ethernet peer-to-peer protocol PPPoE access request message initiated by the UE, and then forwards to the trusted wireless office or the network access gateway TWAG through the L2TP tunnel;

When the TWAG determines that the packet data network PDN connection of the UE is allowed to be established, the PDN connection of the UE is established with the PDN gateway according to the access point name APN information that the UE wants to access, and the PDN gateway is The IP address information allocated by the UE is sent to the UE.

Preferably, the method further includes:

After the BNG receives the PPP or PPPoE access request message initiated by the UE, and determines that the second layer tunneling protocol L2TP tunnel is not established between the BNG and the TWAG, the BNG needs to access according to the acquired UE. The APN information or the L2TP parameter information establishes an L2TP tunnel of the UE with the TWAG.

Preferably, the method further includes:

Establishing, by the BNG and the BWAG, an L2TP session for the PPP or PPPoE request of the UE in the L2TP tunnel;

The TWAG sends the IP address information allocated by the PDN gateway to the UE through the L2TP session and sends the information to the UE via the BNG.

Preferably, the method further includes:

The TWAG initiates an authentication request based on the UE to the 3GPP-certified authorized charging AAA server, and the 3GPP AAA server sends the TWAG to the TWAG through the broadband forum BBF AAA server after the authentication of the UE passes And sending the UE authentication success message or the authorization message, where the UE authentication success message or the authorization message carries the APN access list information.

Preferably, the method further includes: The PPP or PPPoE access request message carries the APN information that the UE wants to access. The TWAG obtains the APN information that the UE wants to access from the PPP or PPPoE access request message initiated by the UE.

Preferably, the method further includes:

The BNG initiates an authentication request based on the UE to a BBF AAA server, and the BBF AAA server sends an authentication request based on the UE to a 3GPP AAA server of the 3rd Generation Partnership Project Organization;

After the authentication by the UE is passed, the 3GPP AAA server sends the UE authentication success message or the authorization message to the BNG through the BBF AAA server; the UE authentication success message or the authorization message carries the L2TP parameter. information.

Preferably, the method further includes:

The TWAG determines, according to the acquired APN information that the UE wants to access and the APN access list information, that the PDN connection of the UE is allowed to be established.

Preferably, the method further includes:

The TWAG sends the IP address information allocated by the PDN gateway to the UE to the UE in an IPCP negotiation process with the UE.

Preferably, the method further includes:

Establishing different sessions between the BNG and the TWAG in different L2TP tunnels for different UEs carrying the same APN information;

Or, the different UEs carrying different APN information between the BNG and the TWAG establish different sessions in the same L2TP tunnel;

Or, the BNG and the TWAG establish different L2TP tunnels for different UEs carrying the same APN information.

Preferably, the method further includes:

The TWAG maintains the L2TP tunnel of the UE and the binding of the session to the GTP/PMIP connection The GTP/PMIP connection is a connection between the BNG and the PDN gateway. A multi-connection established system, the system comprising a BNG, a TWAG and a PDN gateway, wherein:

The BNG is configured to receive the PPP or PPPoE access request message initiated by the UE, and then forward the message to the TWAG through the L2TP tunnel;

The TWAG, configured to determine that a PDN connection of the UE is allowed to be established, establish a PDN connection of the UE with a PDN gateway according to the APN information that the UE wants to access, and allocate the PDN gateway to the UE. The IP address information is sent to the UE.

Preferably, after receiving the PPP or PPPoE access request message initiated by the UE, the BNG is further configured to: when it is determined that the L2TP tunnel is not established between the BNG and the TWAG, according to the acquired UE to be accessed The APN information or the L2TP parameter information establishes an L2TP tunnel of the UE with the TWAG.

Preferably, the BNG sends an L2TP session establishment request to the BWAG for the PPP or PPPoE request of the UE in the L2TP tunnel;

The TWAG is further configured to: send, by the BNG, the IP address information allocated by the PDN to the UE to the UE by using the L2TP tunnel.

Preferably, the system further comprises a 3GPP AAA server and a BBF AAA server, wherein:

The TWAG is further configured to initiate a UE-based authentication request to the BBF AAA server;

The BBF AAA server is further configured to: send the UE-based authentication request sent by the TWAG to the 3GPP AAA server, and receive a UE authentication success message or an authorization message sent by the 3GPP AAA and send the message to the TWAG ;

The 3GPP AAA server is further configured to: after the authentication of the UE passes, send a UE authentication success message or an authorization message to the TWAG by using the BBF AAA server, where The UE authentication success message or the authorization message carries the APN access list information.

Preferably, the BNG is further configured to: initiate an authentication request based on the UE to the BBF AAA server, where the BBF AAA server forwards an authentication request based on the UE to the 3GPP AAA server;

The 3GPP AAA server is further configured to: after the authentication based on the UE passes, send the UE authentication success message or an authorization message to the BNG by using the BBF AAA server; in the UE authentication success message or the authorization message Carry L2TP parameter information.

Preferably, the TWAG is further configured to determine, according to the acquired APN information that the UE wants to access and the APN access list information, that the PDN connection of the UE is allowed to be established.

Preferably, the TWAG is further configured to send the IP address information allocated by the PDN gateway to the UE to the UE in an IPCP negotiation process with the UE.

Preferably, the different UEs carrying the same APN information between the BNG and the TWAG establish different sessions in the same L2TP tunnel;

In the present invention, the BNG receives the Point-to-Point Protocol (PPP) or the Point-to-Point Protocol over Ethernet (PPPoE) access request message initiated by the UE. The L2TP tunnel is forwarded to the TWAG; the TWAG determines, according to the acquired access point name (APN, Access Point Name) information and the APN access list information that the UE wants to access, the APN to be established according to the UE. And the PDN gateway establishes a PDN connection of the UE, and sends the IP address information allocated by the PDN gateway to the UE to the UE by using the BNG, where the BNG and the TWAG are in the same second for different UEs carrying the same APN information. Layer 2 Tunneling Protocol (L2TP, Layer 2 Tunneling Protocol) A different session is established in the tunnel. The BNG and TWAG establish different sessions in the same L2TP tunnel for different UEs carrying different APN information. Alternatively, BNG and TWAG establish different interfaces for different UEs carrying the same APN information. L2TP tunnel. The TWAG maintains the binding relationship between the L2TP tunnel and the session of the UE and the GTP/PMIP connection. The invention realizes the multi-connection establishment based on the APN information, expands the application of the FMC architecture, and can identify the corresponding session through the APN information. DRAWINGS

Figure 1 is a schematic diagram of the FMC architecture;

2 is a flowchart of a method for establishing multiple connections according to Embodiment 1 of the present invention;

3 is a flowchart of a method for establishing multiple connections according to Embodiment 2 of the present invention;

4 is a schematic diagram of encapsulation and decapsulation of data packets of a method for establishing multiple connections according to an embodiment of the present invention. detailed description

The embodiment of the present invention relates to: after receiving the PPP or PPPoE access request message initiated by the UE, the BNG forwards the message to the TWAG; when the TWAG determines that the PDN connection of the UE is allowed to be established, the BNG establishes the UE according to the APN information that the UE wants to access and the PDN gateway. The PDN connection is sent to the UE by the IP address information allocated by the PDN gateway for the UE. The BNG and the TWAG establish different sessions in the same L2TP tunnel for different UEs carrying the same APN information. Alternatively, different UEs carrying different APN information between the BNG and the TWAG establish different sessions in the same L2TP tunnel. Alternatively, a different L2TP tunnel is established between the BNG and the TWAG for different UEs carrying the same APN information. The TWAG maintains the binding relationship between the L2TP tunnel of the UE and the session and the GTP/PMIP connection. The TWAG sends an IP address assigned by the PDN gateway to the UE to the UE during the IPCP (IP (Internet Protocol) Control Protocol) negotiation process with the UE. Specifically, the mobile network user equipment (UE) initiates a PPP or PPPoE access request, and carries the APN information that needs to be accessed.

The BNG according to the APN information carried in the UE request packet or the authentication packet and/or the L2TP parameter information carried in the UE authentication success message or the authorization message sent by the AAA server (3GPP AAA server) server to the BNG to the TWAG Request to establish an L2TP tunnel of the UE. That is, if there is no corresponding L2TP tunnel between the BNG and the TWAG, the L2TP tunnel is established first.

The TWAG is based on the UE identity information carried in the UE request packet or the authentication packet, the APN information, and/or the APN access carried in the UE authentication success message or the authorization message sent by the AAA server (3GPP AAA server) server to the TWAG. The list information determines whether the user establishes a PDN connection with the 3GPP network gateway. If the TWAG determines that the PDN connection of the UE is allowed to be established, the TWAG requests the mobile network gateway (including the PDN GW) to establish a PDN connection of the UE according to the UE information and the APN information carried in the UE request message or the authentication message. And sending the obtained user IP address to the UE via the BNG through the L2TP protocol. The TWAG maintains the binding relationship between the UE's L2TP tunnel and the session and the GTP/PMIP connection.

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

Embodiment 1

2 is a flowchart of a method for establishing multiple connections according to Embodiment 1 of the present invention. As shown in FIG. 2, the method for establishing multiple connections in this example includes the following steps:

Step 201: The UE initiates a PPPoE session ID. The PPPoE session ID is obtained between the UE and the BNG.

Step 202: The PPP Link Control Protocol (LCP) negotiation is completed between the UE and the BNG.

Step 203: The UE carries the APN information and cooperates with the BNG, the BBF AAA server, and the 3GPPAAA. The server interacts to complete the UE identity local authentication, and the 3GPP AAA server sends the Layer 2 Tunneling Protocol (L2TP) parameter information to the BNG.

Step 204: Perform an L2TP tunnel establishment between the BNG and the TWAG.

If an L2TP tunnel or a tunnel with the same APN information already exists between the BNG and the TWAG, this step is omitted. Of course, if there is already an L2TP tunnel or a tunnel with the same APN information between the BNG and the TWAG, the L2TP parameter information is not sent in step 203.

Step 205: The UE carries the APN information and interacts with the TWAG, the BBF AAA server, and the 3GPP AAA server to complete the UE identity local authentication, and establishes an L2TP session between the BNG and the TWAG. The 3GPP AAA server confirms whether the UE user is allowed to access the APN while authenticating the user identity. If the authentication is successful, the 3GPP AAA server returns an authentication success response message to the TWAG through the BBF AAA server.

Step 206: The TWAG compares the APN information carried in the UE authentication request with the APN access list sent by the 3GPP AAA server through the BBF AAA server. If the comparison succeeds, the TWAG and the PDN GW interact to complete the GTP session establishment. In this step, it is determined whether the UE is allowed to access according to the APN information and the APN access list.

Step 207: The UE interacts with the TWAG to complete the IP address allocation, that is, the TWAG sends the IP address to the UE during the IPCP negotiation process with the UE.

Implementation two

The embodiment provides the user authentication of the 3GPP UE accessed from the fixed network (method 2, APN connection pre-establishment authentication) and an APN connection establishment method, where the 3GPP UE is an 802. IX client, and the RG is an 802.1X authenticator. . FIG. 3 is a flowchart of a method for establishing multiple connections according to Embodiment 2 of the present invention. As shown in FIG. 3, the method for establishing multiple connections in this example includes the following steps: Step 301: A 3GPP UE sends an authentication protocol to an RG (EAPoL- Start) The message is authenticated by the 802.1X protocol. The UE is an 802.1X client and the RG is an 802.1X authenticator.

Step 302: After receiving the EAPoL Start message sent by the UE, the RG sends the authentication to the UE. The EAP Identity Request message is used to notify the UE to report the username. After receiving the EAP Identity Request message sent by the RG, the UE sends an EAP Identity Response message to the RG, where the message carries the user name.

Then, the RG encapsulates the received EAP Identity Response message into the RADIUS Access Request message, and the RG also encapsulates the MAC address of the UE into the RADIUS Access Request message, and then sends the message to the RADIUS Access Request message. BNG.

Step 303: The BNG acts as a RADIUS proxy (Proxy), and sends a RADIUS Access Request message (NAI, Network Address Identifier) received from the RG to the corresponding TWAG.

Step 314: The TWAG sends the RADIUS Access Request message received from the BNG to the BBF AAA server according to the NAI of the UE, or the TWAG sends the message according to the NAI of the UE in a scenario where the TWAG has an interface with the 3GPP AAA server. To the 3GPP AAA server;

Step 305: The BBF AAA server forwards the RADIUS Access Request message received by the BNG to the 3GPP AAA server according to the NAI of the UE. If the BBF network uses the RADIUS protocol and the 3GPP network uses the DIAMETER protocol, there is a translation agent (TA) between the BBF AAA server and the 3GPP AAA server for protocol conversion.

If the 3GPP AAA server successfully authenticates the 3GPP AAA server, the 3GPP AAA server returns an authentication success response message to the BBF AAA server and carries the APN access list, and the BBF AAA server returns the authentication success effect message to the TWAG and carries the APN access list. Further, The TWAG replies to the BNG authentication successfully, the BNG returns the authentication to the RG, and the RG replies to the UE successfully. At the same time, under the condition that the UE is authenticated, RG, BNG, and TWAG record the UE's International Mobile Equipment Identity (IMSE).

Step 306: The UE initiates a PPPoE session request, and the PPPoE session is completed between the UE and the BNG to obtain a PPPoE Session ID. Step 307: The PPP LCP negotiation is completed between the UE and the BNG.

Step 308: The UE carries the APN information and interacts with the BNG and BBFAAA servers to complete the UE identity local authentication, and the BNG receives the L2TP parameters sent by the 3GPP AAA server through the BBF AAA server.

Step 309: An L2TP tunnel is established between the BNG and the TWAG.

If an L2TP tunnel or a tunnel having the same APN information already exists between the BNG and the TWAG, the step may be skipped, and the L2TP parameter information may not be sent in the foregoing step 308.

Step 310: The UE, the TWAG, and the BBF AAA server interact to complete the UE identity local authentication. An L2TP session is established between the BNG and the TWAG.

In this step, TWAG may choose not to directly return the authentication success message to the user without interacting with the BBF AAA server.

Step 311: The TWAG compares the APN information carried in the UE authentication request with the APN access list sent by the BBF AAA server. If the comparison succeeds, the TWAG and the PDN GW interact to complete the GTP session establishment.

Step 312: The UE interacts with the TWAG to complete the IP address allocation, that is, the TWAG sends the IP address to the UE during the IPCP negotiation process with the UE.

In the present invention, the foregoing authentication success message may also be an authorization message.

Implementation three

This embodiment provides a process of encapsulating, decapsulating, and transmitting a UE data packet after a 3GPP UE connection established by a fixed network is established. 4 is a schematic diagram of encapsulation and decapsulation of a data packet according to a method for establishing a multi-connection according to an embodiment of the present invention. As shown in FIG. 4, the application steps of the multi-connection establishment method in the embodiment of the present invention include:

Step 401: After the 3GPP UE successfully establishes a connection according to the first embodiment or the second embodiment, the data packet is sent. Specifically, the 3GPP UE puts the corresponding PPPoE encapsulation according to the service type and sends it to the BNG. The format of the data packet is shown in Figure 4, and the structural details thereof will not be described here. Step 402: After receiving the data packet of the UE, the RG directly forwards the data packet.

Step 403: After receiving the data packet of the UE, the BNG performs L2TP encapsulation according to the PPPoE encapsulation information of the packet, and sends the packet to the corresponding TWAG (which is consistent with the TWAG participating in the authentication and connection establishment process). The format of the data packet is shown in Figure 4, and the structural details thereof will not be described here.

Step 404: After receiving the data packet of the UE, the TWAG decapsulates the data packet, obtains the tunnel ID and the session ID in the L2TP header of the packet, and re-encapsulates the IP packet in the packet, and passes between the TWAG and the PND GW. Tunnels (such as GTP tunnels, PMIP tunnels) are sent to the PND GW.

Step 405: The PDN GW receives the data packet of the 3GPP UE.

The invention also describes a system for establishing multiple connections, the system comprising BNG, TWAG and PDN gateways, wherein:

After receiving the PPP or PPPoE access request message initiated by the UE, the BNG is configured to determine that the acquired APN is to be accessed by the UE when the L2TP tunnel is not established between the BNG and the TWAG. The information or the L2TP parameter information is used to establish an L2TP tunnel of the UE with the TWAG.

The system also includes a 3GPP AAA server and a BBF AAA server, wherein: the TWAG is further configured to initiate UE-based authentication to the BBF AAA server Request

The 3GPP AAA server is further configured to: after the authentication of the UE is passed, send a UE authentication success message or an authorization message to the TWAG by using the BBF AAA server, where the UE authentication success message or the authorization message carries an APN connection. Enter the list information.

The TWAG obtains the APN information that the UE wants to access from the PPP or PPPoE access request message initiated by the UE.

The BNG is further configured to initiate an authentication request based on the UE to the BBF AAA server, where the BBF AAA server forwards an authentication request based on the UE to the 3GPP AAA server;

The TWAG is further configured to determine, according to the acquired APN information that the UE wants to access and the APN access list information, that the PDN connection of the UE is allowed to be established.

The TWAG is further configured to: send the IP address information allocated by the PDN gateway to the UE to the UE in an IPCP negotiation process with the UE.

The different UEs carrying the same APN information between the BNG and the TWAG establish different sessions in the same L2TP tunnel;

Or, the BNG and the TWAG establish different L2TP tunnels for different UEs carrying the same APN information. It should be understood by those skilled in the art that the multi-connection established system of the present invention is implemented on the basis of an existing mobile communication network, and the structure of the system is the same as that of the existing FMC architecture, and the multi-connection established system of the present invention is present. Some related network elements in the mobile communication network are implemented by corresponding function expansion. In the present invention, only the network elements whose functions are extended are mainly described. The multi-connection establishment system of the present invention can be understood by referring to the foregoing description of the multi-connection establishment method of the present invention, and its network architecture can be understood with reference to the existing mobile communication network structure such as the structure shown based on FIG.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

Industrial applicability

In the embodiment of the present invention, the BNG receives the peer-to-peer protocol or the Ethernet point-to-point protocol access request message initiated by the UE, and then forwards the message to the TWAG through the L2TP tunnel; the TWAG receives the access point name information and the APN according to the obtained UE to access. When the in-list information determines that the PDN connection of the UE is allowed to be established, the PDN connection of the UE is established with the PDN gateway according to the APN information that the UE wants to access, and the IP address information allocated by the PDN gateway for the UE is sent to the UE through the BNG. The different UEs carrying the same APN information between the BNG and the TWAG establish different sessions in the same Layer 2 tunneling protocol tunnel. Alternatively, the BNG and the TWAG are established in the same L2TP tunnel for different UEs carrying different APN information. Different sessions; or, BNG and TWAG establish different L2TP tunnels for different UEs carrying the same APN information.

The TWAG maintains the binding relationship between the L2TP tunnel and the session of the UE and the GTP/PMIP connection.

Claims

Claim

1. A method for establishing multiple connections, comprising:

2. The method according to claim 1, wherein the method further comprises:

3. The method according to claim 1, wherein the method further comprises:

The method according to any one of claims 1 to 3, wherein the method further comprises: the TWAG initiating an authentication request based on the UE to a 3GPP partner organization organization 3GPP authentication and authorization charging AAA server After the authentication of the UE is passed, the 3GPP AAA server sends the UE authentication success message or the authorization message to the TWAG through the broadband forum BBF AAA server, where the UE authentication success message or the authorization message carries the APN access. List information.

5. The method according to claim 4, wherein the method further comprises: The PPP or PPPoE access request message carries the APN information that the UE wants to access. The TWAG obtains the APN information that the UE wants to access from the PPP or PPPoE access request message initiated by the UE.

The method according to claim 4, wherein the method further comprises:

7. The method according to claim 1, wherein the method further comprises:

8. The method according to claim 1, wherein the method further comprises:

The method according to claim 5, wherein the method further comprises:

The method according to claim 6 or 7, wherein the method further comprises: the TWAG maintaining the L2TP tunnel of the UE and the binding of the session to the GTP/PMIP connection The GTP/PMIP connection is a connection between the BNG and the PDN gateway.

A system for establishing a multi-connection, including a BNG, a TWAG, and a PDN gateway, where: the BNG is configured to receive a PPP or PPPoE access request message initiated by the UE,

The L2TP tunnel is forwarded to the TWAG;

12. The system of claim 11 wherein:

After receiving the PPP or PPPoE access request message initiated by the UE, the BNG is further configured to: when determining that the L2TP tunnel is not established between the BNG and the TWAG, according to the acquired APN information that the UE wants to access or The L2TP parameter information is used to establish an L2TP tunnel of the UE with the TWAG.

13. The system of claim 11 wherein:

The BWAG sends an L2TP session establishment request.

14. The system according to any one of claims 11 to 13, the system further comprising a 3GPP AAA server and a BBF AAA server, wherein:

The 3GPP AAA server is further configured to: after the authentication of the UE passes, pass the The BBF AAA server sends a UE authentication success message or an authorization message to the TWAG, where the UE authentication success message or the authorization message carries the APN access list information.

The system according to claim 14, wherein the BNG is further configured to initiate an authentication request based on the UE to the BBF AAA server, and the BBF AAA server forwards the originating basis to the 3GPP AAA server. Said UE authentication request;

The system according to claim 15, wherein the TWAG is further configured to determine, according to the acquired APN information that the UE wants to access and the APN access list information, that the PDN connection of the UE is allowed to be established.

The system according to claim 15, wherein the TWAG is further configured to: send, in the IPCP negotiation process with the UE, IP address information allocated by the PDN gateway to the UE to the UE.

18. The system of claim 15 wherein: