WO2014121760A1

WO2014121760A1 - Method and device for selecting network apparatus during switching

Info

Publication number: WO2014121760A1
Application number: PCT/CN2014/071906
Authority: WO
Inventors: 段小嫣; 高晨亮; 金辉; 衣强
Original assignee: 华为终端有限公司
Priority date: 2013-02-08
Filing date: 2014-02-08
Publication date: 2014-08-14
Also published as: CN103987092B; CN103987092A

Abstract

The embodiments of the present invention provide a method and apparatus for selecting a network device during switching. The method comprises: receiving a switching request message which is sent by a user equipment and used for indicating to switch an access network used by a session of the user equipment to a first access network from a second access network; acquiring a first access point name used when the user equipment accesses a core network through the second access network and an identification of a first packet data network gateway corresponding to the first access point name; and selecting the first access point name as an access point name used after the session of the user equipment is switched to the first access network, and selecting a packet data network gateway indicated by the identification of the first packet data network gateway as a packet data network gateway used after the session of the user equipment is switched to the first access network. By adopting the present invention, when a UE is switched between access networks, the IP address will not change, thereby effectively avoiding the problem of transmission interruption of IP data streams of the UE.

Description

The present application claims priority to Chinese Patent Application No. 201310050277.0, filed on Feb TECHNICAL FIELD The present invention relates to the field of communications, and more particularly to a method and apparatus for selecting a network device during handover. BACKGROUND A third-generation mobile communication network is implemented according to a standard organization of the 3GPP (3rd Generation Partnership Project), which can be called a mobile communication network or a 3GPP network, and is currently the most widely used application. Wide area mobile communication network. The WLAN (Wireless Local Access Network) is widely deployed and used as a local communication network with convenient access, high speed and relatively low price. Users can use the UE (User Equipment) to access the 3GPP network or WLAN network for data services, such as accessing the Internet, downloading text/audio/video data, and so on.

The UE can also access the 3GPP core network through the WLAN to facilitate access to the Internet through the 3GPP core network, thereby implementing interworking between the 3GPP network and the WLAN, facilitating the 3GPP network to offload data payloads to the WLAN, and perform unified charging and QoS (Quality of Service). , quality of service) control, etc.

Currently, the 3GPP standard specifies that the UE passes TWAN (Trusted Wireless Access).

Network, trusted wireless access network) access to the 3GPP evolved packet core network EPC (Evolved Packet Core, Evolved Packet Core) attachment (ie, registration) process, where TWAN is based on 3GPP HSS (Home Subscriber Server) , the home subscription server) /AAA Server (Authentication, Authorization and Accounting Server) obtained the subscription data for the UE to select the default APN (Access Point Name). Here, the default APN is marked as "default" in the subscription data corresponding to the UE. (default) APN; when the UE registers with the network or requests to establish a packet data connection, if the UE does not provide the APN, the network side uses the default APN. For one UE, 1) the UE uses when accessing through the TWAN The default APN may be different from the default APN used by the UE when accessing the 3GPP, so that the PDN GW (Packet Data Network Gateway) used by the UE during TWAN access may be the PDN used by the UE when the 3GPP is accessed. GW is different; 2) When the default APN used by the UE through the TWAN access is the same as the default APN used by the UE through the 3GPP access, the PDN GW used by the UE during the TWAN access may also be the PDN used by the UE when the 3GPP accesses GW is different.

Therefore, it is promoted to the non-3GPP access network by the trusted WLAN access network, and is used by the PDN GW and the 3GPP access network used by the non-3GPP access network after the UE switches to the 3GPP EPC through the non-3GPP access network. The PDN GW is different. Then, the IP address used by the UE will be inconsistent before and after the handover, thereby causing the IP data stream transmission of the UE to be interrupted. Summary of the invention

An object of the present invention is to provide a method and apparatus for selecting a network device in a handover process, which aims to solve the problem that the IP data stream transmission is interrupted when the UE switches from the non-3GPP access network to the 3GPP access network.

In one aspect, an embodiment of the present invention provides a method for selecting a network device in a handover process, where the method includes:

Receiving, by the user equipment, an indication that the access network used by the session of the user equipment is switched from the second access network to a handover request message of the first access network;

Acquiring the first access point name used by the user equipment when accessing the core network by using the second access network, and acquiring, by the first network device, the user equipment accessing the core network through the second access network The identifier of the first packet data network gateway that is used by the first access point name, where the first network device is a network device that manages the user equipment by the network side, and the management is: subscription management, One or more of authentication management and location management; Selecting the first access point name as the access point name used by the session of the user equipment after switching to the first access network, and selecting the group indicated by the identifier of the first packet data network gateway The data network gateway switches to the packet data network gateway used after the first access network as the session of the user equipment.

With reference to the first aspect, in a first possible implementation manner, the acquiring, by the first network device, the first access point that is used when the user equipment accesses a core network by using the second access network The step of identifying the identifier of the first packet data network gateway corresponding to the name includes:

Sending a first request message to the first network device, where the first request message is used to request to obtain an identifier of a first packet data network gateway used by the user equipment to access the core network through the second access network. ;

Receiving a first response message sent by the first network device, where the first response message carries at least the identifier of the first packet data network gateway, and the identifier of the first packet data network gateway is connected to the first interface The entry name corresponds.

With reference to the first possible implementation manner of the first aspect, in a second possible implementation manner, the first request message is a location update request or an authentication request or a gateway update request, where the first response message is a location Updating the response or the authentication response or the gateway update response, the first network device being a home subscription server or an authentication server.

With reference to the first possible implementation of the first aspect, or the second possible implementation of the first aspect, in a third possible implementation, the method further includes:

The first request message carries the first indication information, so that the first network device determines, according to the first indication information, that the access network used by the user equipment is changed by the second access network. After the first access network, the step of sending the first response message is performed, where the first indication information indicates that the access network used by the session before the handover is the second access network or the indication The access network used by the session is switched by the second access network to the first access network; and/or the first network device determines the type of radio access technology of the user equipment by using the The second access network is changed to the first access network, and the access network used by the user equipment is determined to be The step of transmitting the first response message after the second access network becomes the first access network.

With reference to the first aspect, or the first possible implementation of the first aspect, or the first possible implementation of the first aspect, or the second possible implementation of the first aspect, or the first aspect In a fourth possible implementation manner, the identifier of the first packet data network gateway is specifically acquired by the first network device from a second network device, where the second network device is An authentication server used by the user equipment to access the core network through the second access network.

With reference to the first aspect, or the first possible implementation of the first aspect, or the first possible implementation of the first aspect, or the second possible implementation of the first aspect, or the first aspect The third possible implementation manner, or the fourth possible implementation manner of the first aspect, in the fifth possible implementation manner, the selecting the first access point name as the session of the user equipment Switching to the access point name used after the first access network, selecting the packet data network gateway indicated by the identifier of the first packet data network gateway as the session of the user equipment, switching to the first The packet data network gateway used after accessing the network is specifically:

And selecting, according to the second indication information, the first access point name as the access point name used by the session of the user equipment after switching to the first access network, and selecting the first packet data network gateway The packet data network gateway indicated by the identifier is used as a packet data network gateway used after the session of the user equipment is switched to the first access network, and the second indication information indicates that the session is used before the handover. The access network is the second access network or the access network indicating the use of the session is switched by the second access network to the first access network, the handover request message and/or the A response message carries the second indication information.

With reference to the first aspect, or the first possible implementation of the first aspect, or the first possible implementation of the first aspect, or the second possible implementation of the first aspect, or the first aspect Three possible implementations, or the fourth possible implementation of the first aspect The fifth possible implementation manner of the first aspect, in a sixth possible implementation manner, the acquiring, by using the first access network, the user equipment accessing the core network by using the second access network The entry name is specifically:

Obtaining, by the handover request message, the first access point name, where the handover request message carries a first access point name used by the user equipment to access the core network by using the second access network; or ,

Obtaining, by the first network device, a first access point name used by the user equipment to access the core network through the second access network.

The first possible implementation of the first aspect, or the first possible implementation of the first aspect, or the second possible implementation of the first aspect, or the third possible implementation of the first aspect The fourth possible implementation manner of the first aspect, or the fifth possible implementation manner of the first aspect, in combination with the sixth possible implementation manner of the first aspect, in the seventh possible implementation manner The switching request message carries the first access point name, so that the first request message carries the first access point name, so that the first network device is configured according to the first The request message acquires an identifier of the first packet data network gateway corresponding to the first access point name.

With reference to the first aspect, or the first possible implementation of the first aspect, or the first possible implementation of the first aspect, or the second possible implementation of the first aspect, or the first aspect The three possible implementation manners, or the fourth possible implementation manner of the first aspect, or the fifth possible implementation manner of the first aspect, or the sixth possible implementation manner of the first aspect, or the first aspect A seventh possible implementation manner, in an eighth possible implementation, the access network sent by the receiving user equipment is used to switch the access network used by the session from the second access network to the first access network. The method further includes: before the step of acquiring the identifier of the first packet data network gateway corresponding to the first access point name, after the step of the handover request message, the method further includes:

Determining, according to the name of the second access point that the user equipment signs in the first access network, Determining, by the identifier of the second packet data network gateway corresponding to the second access point name in the first access network, a second packet data network gateway, and sending a setup session request message to the second packet data network gateway;

After receiving the message that the second packet data network gateway sends a session failure or a handover failure, performing the obtaining, by the first network device, the first packet data corresponding to the first access point name. The step of identifying the network gateway.

With reference to the first aspect, or the first possible implementation of the first aspect, or the first possible implementation of the first aspect, or the second possible implementation of the first aspect, or the first aspect The three possible implementation manners, or the fourth possible implementation manner of the first aspect, or the fifth possible implementation manner of the first aspect, or the sixth possible implementation manner of the first aspect, or the first aspect The seventh possible implementation manner, or the eighth possible implementation manner of the first aspect, in the ninth possible implementation manner, the first response message is specifically configured by the first network device Send:

Determining, by the user equipment, the first access point name used when the user equipment accesses the core network by using the second access network, and the second used by the user equipment when accessing the core network by using the first access network Access point name is different; or,

Determining, by the user equipment, the first access point name used when accessing the core network by using the second access network, and the second access used by the user equipment when accessing the core network by using the first access network The point name is the same, but the identifier of the first packet data network gateway is different from the identifier of the second packet data network gateway used by the user equipment when accessing the core network by using the first access network, and the second group is different. The identity of the data network gateway corresponds to the second access point name.

In a second aspect, the embodiment of the present invention further provides a method for selecting a network device in a handover process, where the method includes:

Receiving a first request message sent by the third network device, where the first request message is that the third network device receives the indication sent by the user equipment to switch the access network used by the session from the second access network to the first After the handover request message of the access network is sent, the first request message is used for And obtaining, by the user equipment, an identifier of a first packet data network gateway used by the user equipment to access the core network by using the second access network, where the third network device is a network device that selects a packet data network gateway;

Sending a first response message to the third network device, where the first response message carries at least the identifier of the first packet data network gateway, so that the third network device selects the first access point name as the The session of the user equipment is switched to the access point name used after the first access network, and the packet data network gateway indicated by the identifier of the first packet data network gateway is selected as the user equipment The packet data network gateway used after the session is switched to the first access network, where the first access point name is used by the user equipment when accessing the core network through the second access network. The first access point name is obtained by the third network device from the handover request message or the first response message, and the identifier of the first packet data network gateway is the first The access point name corresponds.

With reference to the second aspect, in a first possible implementation manner, the first request message is a location update request or an authentication request or a gateway update request, where the first response message is a location update response or an authentication response or a gateway. Updating the response, the third network device is a network device that selects a packet data network gateway.

With reference to the second aspect, or the first possible implementation manner of the second aspect, in a second possible implementation, before the step of sending the first response message to the third network device, the method further includes: determining The access network used by the user equipment is changed from the second access network to the first access network, specifically:

Determining, according to the first indication information, that the access network used by the user equipment is changed from the second access network to the first access network, where the first indication information indicates that the session is used before the handover. The access network is the second access network or the access network indicating that the session is used is switched from the second access network to the first access network, and the first request message carries the first An indication message; or,

Determining, by the second access network, that the type of radio access technology of the user equipment is changed to The first access network determines that the access network used by the user equipment is changed from the second access network to the first access network.

With reference to the second aspect, or the first possible implementation manner of the second aspect, or the second possible implementation manner of the second aspect, in a third possible implementation manner, The identifier of the first packet data network gateway is specifically obtained from the second network device, where the second network device is an authentication server used by the user equipment to access the core network through the second access network.

With reference to the second aspect, or the first possible implementation of the second aspect, or the second possible implementation of the second aspect, or the third possible implementation of the second aspect, in the fourth possible In an implementation manner, the identifier of the first packet data network gateway that is included in the first response message includes: the first response message carrying the first access point name and the first packet data network gateway Logo.

With reference to the second aspect, or the first possible implementation manner of the second aspect, or the second possible implementation manner of the second aspect, or the third possible implementation manner of the second aspect, or the second aspect In a fifth possible implementation manner, the method further includes: carrying the first access point name in the handover request message, to carry the first request message The first access point name, according to the first access point name carried in the first request message, carrying at least the identifier of the first packet data network gateway in the first response message, where The identifier of the first packet data network gateway corresponds to the first access point name.

With reference to the second aspect, or the first possible implementation manner of the second aspect, or the second possible implementation manner of the second aspect, or the third possible implementation manner of the second aspect, or the second aspect The fourth possible implementation manner, or the fifth possible implementation manner of the second aspect, in a sixth possible implementation manner, before the step of sending the first response message to the third network device, The method also includes:

Determining the first used by the user equipment when accessing the core network by using the second access network The access point name is different from the second access point name used by the user equipment when accessing the core network by using the first access network; or

In a third aspect, the embodiment of the present invention further provides a device for selecting a network device in a handover process, where the device includes:

a handover request message receiving unit, configured to receive a handover request message sent by the user equipment, indicating that the access network used by the session of the user equipment is switched from the second access network to the first access network; Obtaining a first access point name used when the user equipment accesses the core network by using the second access network;

a second acquiring unit, configured to acquire, by the first network device, a first packet data network gateway corresponding to the first access point name used by the user equipment when accessing the core network by using the second access network And the first network device is a network device that manages the user equipment by the network side, where the management is: one or more of subscription management, authentication management, and location management; and a selecting unit, configured to select The first access point name obtained by the acquiring unit is used as the access point name used after the session of the user equipment is switched to the first access network, and the first packet data network acquired by the acquiring unit is selected. And the packet data network gateway indicated by the identifier of the gateway is switched to the packet data network gateway used after the first access network as the session of the user equipment.

With reference to the third aspect, in a first possible implementation, the second acquiring unit includes:

a first request message sending subunit, configured to send a first request message to the first network device, where the first request message is used to request that the user equipment be connected by using the second access network The identifier of the first packet data network gateway used when entering the core network;

a first response message receiving subunit, configured to receive, after the first request message sending subunit sends the first request message, a first response message sent by the first network device, where the first response message carries at least The identifier of the first packet data network gateway, where the identifier of the first packet data network gateway corresponds to the first access point name.

With reference to the first possible implementation manner of the third aspect, in a second possible implementation manner, the first request message is a location update request or an authentication request or a gateway update request, where the first response message is a location Updating the response or the authentication response or the gateway update response, the first network device being a home subscription server or an authentication server.

With the first possible implementation of the third aspect, or the second possible implementation of the third aspect, in a third possible implementation, the first request message carries the first indication information, And causing the first network device to determine, according to the first indication information, that the access network used by the user equipment is changed from the second access network to the first access network, and then performing the sending the first response. a step of the message, the first indication information indicating that the access network used by the session before the handover is the second access network or the access network indicating that the session is used is switched from the second access network to The first access network.

With reference to the third aspect, or the first possible implementation manner of the third aspect, or the second possible implementation manner of the third aspect, or the third possible implementation manner of the third aspect, in the fourth possible In an implementation manner, the identifier of the first packet data network gateway acquired by the second acquiring unit is specifically acquired by the first network device from the second network device, where the second network device is the user equipment The authentication server used when the access network accesses the core network.

With reference to the third aspect, or the first possible implementation manner of the third aspect, or the second possible implementation manner of the third aspect, or the third possible implementation manner of the third aspect, or the third aspect In a fifth possible implementation manner, the selecting unit is specifically configured to:

Determining, according to the second indication information, the first access point name as a location of the user equipment Determining, by the session, the access point name used after the first access network is switched, selecting the packet data network gateway indicated by the identifier of the first packet data network gateway as the session of the user equipment, switching to the a packet data network gateway used after the first access network, where the second indication information indicates that the access network used by the session before the handover is the second access network or indicates that the session is used for access The network is switched by the second access network to the first access network, and the handover request message and/or the first response message carries the second indication information.

With reference to the third aspect, or the first possible implementation manner of the third aspect, or the second possible implementation manner of the third aspect, or the third possible implementation manner of the third aspect, or the third aspect The fourth possible implementation manner, or the fifth possible implementation manner of the third aspect, in the sixth possible implementation manner, the first acquiring unit is specifically configured to obtain the foregoing information from the handover request message An access point name, where the handover request message carries a first access point name used by the user equipment to access the core network through the second access network; or, specifically, from the first network device Obtaining a first access point name used by the user equipment when accessing the core network by using the second access network.

With reference to the third aspect, or the first possible implementation manner of the third aspect, or the second possible implementation manner of the third aspect, or the third possible implementation manner of the third aspect, or the third aspect The four possible implementation manners, or the fifth possible implementation manner of the third aspect, or the sixth possible implementation manner of the third aspect, where the handover request message is carried in the seventh possible implementation manner The first access point name, so that the first request message carries the first access point name, so that the first network device acquires the first request message according to the first request message. The identifier of the first packet data network gateway corresponding to the access point name.

With reference to the third aspect, or the first possible implementation manner of the third aspect, or the second possible implementation manner of the third aspect, or the third possible implementation manner of the third aspect, or the third aspect Four possible implementations, or a fifth possible implementation of the third aspect, or a sixth possible implementation of the third aspect, or a seventh of the third aspect In an implementation manner, in an eighth possible implementation, before the receiving unit receives, the device further includes:

a session request message sending unit, configured to: after the switching request message receiving unit receives the switching request message, before the second obtaining unit acquires the identifier of the first packet data network gateway, according to the user Selecting, by the device, the second access point name signed in the first access network and the identifier of the second packet data network gateway corresponding to the second access point name in the first access network to select the second group a data network gateway, sending a setup session request message to the second packet data network gateway;

An execution unit, configured to receive, by the second packet data network gateway, a message indicating that a session failure or a handover failure is established, notify the second obtaining unit to acquire, by the first network device, the user equipment by using the second connection The identifier of the first packet data network gateway corresponding to the first access point name used when accessing the core network.

In a fourth aspect, the embodiment of the present invention further provides a device for selecting a network device in a handover process, where the device includes:

a first request message receiving unit, configured to receive a first request message sent by the third network device, where the first request message is an access network that is sent by the third network device to receive the indication sent by the user equipment After the second access network is switched to the handover request message of the first access network, the first request message is used to request to acquire the first used by the user equipment to access the core network through the second access network. An identifier of a packet data network gateway, where the third network device is a network device that selects a packet data network gateway;

a first response message sending unit, configured to send a first response message to the third network device, where the first response message carries at least the identifier of the first packet data network gateway, so that the third network device Selecting a first access point name as the access point name used by the session of the user equipment after switching to the first access network, and selecting packet data indicated by the identifier of the first packet data network gateway The network gateway is used as the packet data network gateway used by the user equipment to switch to the first access network, where the first access point name is An access point name used by the user equipment when accessing the core network by using the second access network, where the first access point name is used by the third network device from the handover request message or the first Obtained in the response message, the identifier of the first packet data network gateway corresponds to the first access point name.

With reference to the fourth aspect, in a first possible implementation manner, the first request message is a location update request or an authentication request or a gateway update request, where the first response message is a location update response or an authentication response or a gateway. Updating the response, the third network device is a network device that selects a packet data network gateway.

With reference to the fourth aspect, or the first possible implementation manner of the fourth aspect, in a second possible implementation, the apparatus further includes:

a determining unit, configured to determine, before the first response message sending unit sends the first response message, that an access network used by the user equipment is changed from the second access network to the first access network .

With reference to the second possible implementation of the fourth aspect, in a third possible implementation, the determining unit is specifically configured to:

Before the first response message sending unit sends the first response message, determining, according to the first indication information, that the access network used by the user equipment is changed from the second access network to the first access a network, where the first indication information indicates that an access network used by the session before handover is the second access network or an access network indicating that the session is used is switched from the second access network to The first access message, the first request message carries the first indication information; or

Before the first response message sending unit sends the first response message, determining that the type of the radio access technology of the user equipment is changed from the second access network to the first access network, The access network used by the user equipment is changed from the second access network to the first access network.

With reference to the fourth aspect, or the first possible implementation manner of the fourth aspect, or the second possible implementation manner of the fourth aspect, or the third possible implementation manner of the fourth aspect, In the four possible implementation manners, the identifier of the first packet data network gateway that is carried in the first response message is specifically acquired by the second network device, where the second network device is the user equipment An authentication server used when the second access network accesses the core network.

With reference to the fourth aspect, or the first possible implementation manner of the fourth aspect, or the second possible implementation manner of the fourth aspect, or the third possible implementation manner of the fourth aspect, or the fourth aspect In a fifth possible implementation manner, the identifier that the at least the first packet data network gateway carries in the first response message includes: the first response message carrying the first An access point name and an identification of the first packet data network gateway.

With reference to the fourth aspect, or the first possible implementation manner of the fourth aspect, or the second possible implementation manner of the fourth aspect, or the third possible implementation manner of the fourth aspect, or the fourth aspect The fourth possible implementation manner, or the fifth possible implementation manner of the fourth aspect, in the sixth possible implementation manner, the switching request message carries the first access point name, so that the The first request message carries the first access point name, and carries at least the first packet data in the first response message according to the first access point name carried in the first request message. An identifier of the network gateway, where the identifier of the first packet data network gateway corresponds to the first access point name.

With reference to the fourth aspect, or the first possible implementation manner of the fourth aspect, or the second possible implementation manner of the fourth aspect, or the third possible implementation manner of the fourth aspect, or the fourth aspect The fourth possible implementation manner, or the fifth possible implementation manner of the fourth aspect, or the sixth possible implementation manner of the fourth aspect, in a seventh possible implementation manner, the device further includes a determining unit , specifically for:

Before the first response message sending unit sends the first response message, determining, by the user equipment, the first access point name used by the user equipment to access the core network by using the second access network, and the user The second access point name used by the device when accessing the core network by using the first access network is different; or Before the first response message sending unit sends the first response message, determining, by using the first access point name used by the user equipment to access the core network by using the second access network, and the user equipment The second access point name used by the first access network to access the core network is the same, but the identifier of the first packet data network gateway and the user equipment access the core network through the first access network. The identifier of the second packet data network gateway used at the time is different, and the identifier of the second packet data network gateway corresponds to the second access point name.

In the embodiment of the present invention, when the UE switches between the access networks, the UE does not establish a connection between the UE and the new access network by assigning a new APN and a PDN GW, but obtains access through a new acquisition process. The network device, such as the PDN GW, used in the original access network, so that the IP address does not change after the UE switches to another access network, and the problem of interruption of the IP data stream transmission of the UE is avoided. DRAWINGS

1 is a schematic flow chart of a method for selecting a network device in a handover process according to an embodiment of the present invention;

2 is a schematic flowchart of a specific method for obtaining an identifier of a packet data network gateway according to an embodiment of the present invention;

3 is a schematic flowchart of a method for selecting a network device in another handover process according to an embodiment of the present invention;

4 is a schematic flowchart of a method for selecting a network device in another handover process according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a specific process of a method for selecting a network device in a handover process according to an embodiment of the present invention; FIG.

6 is a schematic diagram of another specific process of a method for selecting a network device in a handover process according to an embodiment of the present invention;

FIG. 7 is still another example of a method for selecting a network device in a handover process according to an embodiment of the present invention; Specific process diagram;

FIG. 8 is a schematic diagram of still another specific process of a method for selecting a network device in a handover process according to an embodiment of the present invention; FIG.

FIG. 9 is a schematic structural diagram of a device for selecting a network device in a handover process according to an embodiment of the present invention; FIG.

10 is a schematic diagram of a specific structure of the second acquiring unit in FIG. 9; FIG. 11 is a schematic structural diagram of an apparatus for selecting a network device in another switching process according to an embodiment of the present invention;

FIG. 12 is a schematic structural diagram of a device for selecting a network device in another handover process according to an embodiment of the present invention; FIG.

FIG. 13 is a schematic structural diagram of a network device according to an embodiment of the present invention; FIG. 14 is a schematic structural diagram of another network device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION In order to make the objects, technical solutions and advantages of the present invention more comprehensible, the present invention will be further described in detail below with reference to the accompanying drawings. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

FIG. 1 is a schematic flowchart of a method for selecting a network device in a handover process according to an embodiment of the present invention. The method in the embodiment of the present invention may be applied to user equipment UE performing access switching between different access networks. The selection of the network device, including the packet data network gateway PDN GW, may be performed by a device having a network device selection function, such as an MME (Mobility Management Entity), which is specifically described in the embodiment of the present invention. Methods include:

S101: Receive a handover request message that is sent by the user equipment to switch the access network used by the session of the user equipment from the second access network to the first access network.

The user equipment UE may be when receiving the network switching instruction of the user, or when detecting the overlay Generating and transmitting the indication when the cover signal is better than the second access network of the first access network

The access network used by the session of the UE is switched by the second access network to the handover request message of the first access network, where the handover request message is specifically a message for requesting network handover, for example, if the UE needs to connect from the non-3GPP When the network is switched to the 3GPP access network, the handover request message may be an attach request message (attach request) sent by the UE to the corresponding MME.

S102: Obtain a first access point name used by the user equipment to access the core network by using the second access network, and obtain, by the first network device, the user equipment to access by using the second access network. The identifier of the first packet data network gateway corresponding to the first access point name used by the core network.

The first network device is a network device that manages the user equipment on the network side, such as a home subscription server HSS or an authentication server, and the management is: one of subscription management, authentication management, and location management. A variety. When the UE accesses the core network through the second access network, the first network device acquires and stores the APN used by the UE and the corresponding PDN GW.

Optionally, the first access point name, that is, the first APN, may be directly obtained from the handover request message, that is, the UE may carry the user equipment through the second access network in the handover request message. The first APN used when accessing the core network; that is, the first access point name may be directly reported by the user equipment. Or: obtaining, by the first network device, the first APN that is used by the user equipment to access the core network by using the second access network, that is, according to information such as the identifier of the user equipment, such as the HSS. Waiting for the first network device to obtain the request after the lookup.

The first packet data network gateway, that is, the identifier of the first PDN GW, may obtain the corresponding first PDN according to the first APN to the first network device after determining the first APN of the UE. GW's logo. Of course, in other embodiments, the first network device, such as an HSS, may also be obtained according to the identifier of the user equipment UE. The identifier of the first PDN GW may be a first PDN GW address, or a PDN GW FQDN (Fully Qualified Domain Name). S103: The first access point name is selected as the access point name used by the user equipment after the session is switched to the first access network, and the identifier of the first packet data network gateway is selected. The packet data network gateway switches to the packet data network gateway used after the first access network as the session of the user equipment.

The UE continues to access the first access network through the APN and the PDN GW used in the second access network, thereby implementing access to the core network for various types of data access, interaction, and the like.

Specifically, the S103 may include: selecting, according to the second indication information, the first access point name as an access point name used by the session of the user equipment after the session is switched to the first access network. And selecting, by the packet data network gateway indicated by the identifier of the first packet data network gateway, the packet data network gateway used after the session of the user equipment is switched to the first access network, the second indication The information indicates that the access network used by the session before the handover is the second access network or the access network indicating that the session is used is switched from the second access network to the first access network, The handover request message and/or the first response message carries the second indication information.

After obtaining the identifiers of the first APN and the first PDN GW that are used when the UE accesses the first access network to access the core network, according to the second indication information in the handover request message or the first network device according to the first The second indication information carried in the first response message returned by the request message initiates a session establishment process.

In the embodiment of the present invention, when the UE switches between the access networks, the network device used when accessing the core network through the original access network before the handover is selected in the handover process is implemented by the process of the embodiment of the present invention. Specifically, During the handover process, the packet data network gateway used when accessing the core network through the original access network is selected, so that the IP address does not change after the UE switches to another access network, and the IP data flow of the UE is avoided. The problem of transmission interruption.

2 is a schematic flowchart of a method for obtaining an identifier of a packet data network gateway according to an embodiment of the present invention. The method for obtaining an identifier of a packet data network gateway according to an embodiment of the present invention includes: S1001: Send a first request message to the first network device, where the first request message is used to request to acquire a first packet data network gateway used by the user equipment to access the core network by using the second access network. Identification

S1002: Receive a first response message sent by the first network device, where the first response message carries at least the identifier of the first packet data network gateway, and the identifier of the first packet data network gateway and the first An access point name corresponds.

The first request message may include the identifier and/or user information of the UE and/or the first APN (directly reported by the UE) used by the UE to access the second access network, etc., to facilitate the first network such as the HSS. The device can search for the identifier of the PDN GW used by the UE when accessing the second access network, and return the identifier of the first PDN GW that is the discovered PDN GW identifier. The UE may carry the first access point name in the handover request message, so that the first request message carries the first access point name, so that the first network device, such as the HSS, is configured according to the The first request message acquires an identifier of the first packet data network gateway corresponding to the first access point name.

The identifier of the first packet data network gateway may be specifically acquired by the first network device from the second network device, where the second network device is accessed by the user equipment by using the second access network. The authentication server used by the core network. That is, the first network device, such as the HSS, may also obtain the second network device, such as an AAA Server for authentication, authorization, and accounting, according to the identifier of the corresponding UE when receiving the first request message. The UE accesses the PDN GW identifier used by the second access network, so that the first network device can return the identifier of the corresponding first PDN GW according to the first request message.

Specifically, the first request message may be a location update request or an authentication request or a gateway update request, where the first response message may be a location update response or an authentication response or a gateway update response corresponding to the first request message. The first network device may be a home subscription server or an authentication server.

Further, before the first network device returns the first response message according to the first request message, First, the first request message may be used to determine whether the access network used by the UE is switched. If yes, the identifier of the first PDN GW is obtained, and the first response message that carries the identifier of the first PDN GW is returned. This is achieved by the following steps:

The first request message carries the first indication information, so that the first network device determines, according to the first indication information, that the access network used by the user equipment is changed by the second access network. After the first access network, the step of sending the first response message is performed, where the first indication information indicates that the access network used by the session before the handover is the second access network or the indication The access network used by the session is switched by the second access network to the first access network; and/or the first network device determines the type of radio access technology of the user equipment by using the The second access network is changed to the first access network, and determining that the access network used by the user equipment is changed from the second access network to the first access network, and the sending the first response is performed. The steps of the message.

Specifically, the first request message may be a location update request or an authentication request or a gateway update request, where the first request message may carry the first indication information, indicating that the access network used by the session before the handover is the second connection Entering the network or indicating that the access network used by the session is switched by the second access network to the first access network; after receiving the first request message, the first network device is configured according to the first request The first indication information carried in the message, and/or determining the type of the radio access technology of the user equipment by the second access network according to the type of the radio access technology of the user equipment stored by the first network device For the first access network.

Further optionally, the first response message is specifically sent by the first device in the following situation:

It is to be understood that the method for obtaining the identifier of the packet data network gateway in the embodiment of the present invention may be corresponding to the acquiring, by the second network access, the user equipment from the first network device in S102 in FIG. The step of identifying the first packet data network gateway corresponding to the first access point name used by the network to access the core network.

As can be seen from the description of the above embodiments, the present invention has the following advantages:

The handover procedure disclosed in the embodiment of the present invention can ensure that the UE continues to use the PDN GW used by the original access network to access the core network before switching, so that the IP address does not change after switching to the new access network. The problem of interruption of the IP data stream transmission of the UE is avoided.

Referring to FIG. 3, it is a schematic flowchart of a method for selecting a network device in another handover process according to an embodiment of the present invention. The method in this embodiment specifically includes:

S201: Receive a handover request message that is sent by the user equipment to switch the access network used by the session of the user equipment from the second access network to the first access network.

S202: According to the second access point name that is subscribed by the user equipment in the first access network, and the second packet data network gateway corresponding to the second access point name in the first access network. The identifier selects the second packet data network gateway, and sends a setup session request message to the second packet data network gateway.

That is, when receiving the handover request message, first try to obtain the second access point name of the user equipment directly from the subscription data, and directly obtain the second packet data network gateway corresponding to the second access point name. At this time, if the obtained second access point name is the same as the first access point name when the user equipment accesses the core network through the second access network, the identifier of the corresponding second PDN GW that may be obtained is also The first PDN GW corresponding to an APN is the same, and a session establishment request may also be initiated to establish a session and ensure that the IP transmission is not interrupted.

If the first PDN and the second PDN are different because the first APN is different from the second APN When the GWs are not the same; or although the first APN and the second ANP are the same, but the first PDN GW and the second PDN GW are still different, after the session establishment request is initiated, the corresponding second PDN GW cannot identify the handover request message. The switching instruction causes the session establishment to fail, and then S203 described below is executed.

S203: Receive a message sent by the second packet data network gateway indicating that the establishment session fails or the handover fails. When receiving the message indicating that the establishment of the session fails or the handover fails, the following S204 needs to be performed to initiate the acquisition of the first APN and the first PDN GW used by the UE to access the second access network.

S204: Acquire a first access point name used by the user equipment to access the core network by using the second access network, and obtain, by the first network device, the user equipment accessing the core by using the second access network. The identifier of the first packet data network gateway corresponding to the first access point name used by the network, the first network device is a network device that manages the user equipment by the network side, and the management is: signing One or more of management, authentication management, and location management.

S205: The first access point name is selected as the access point name used by the session of the user equipment after the session is switched to the first access network, and the identifier of the first packet data network gateway is selected. The packet data network gateway switches to the packet data network gateway used after the first access network as the session of the user equipment.

It should be noted that, in comparison with the foregoing embodiment corresponding to FIG. 1, the embodiment of the present invention is that the access network sent by the receiving user equipment indicates that the access network used by the session is switched from the second access network to the first interface. After the step of the network switching request message, the step of acquiring the identifiers of the first packet data network gateway corresponding to the first access point name from the first network device is newly added, and the steps of S202 and S203 are newly added. The S201 and the S101 are performed in the same manner, and the S204 and S205 are corresponding to the foregoing S102 and S103, and the specific implementation process is not described herein.

The handover procedure disclosed in the embodiment of the present invention can ensure that the UE is handed over to the new access network. After that, the PDN GW used when accessing the core network through the original access network before the handover is continued, so that the IP address does not change, and the problem that the IP data stream transmission of the UE is interrupted is avoided.

Referring to FIG. 4, it is a schematic flowchart of a method for selecting a network device in a handover process according to an embodiment of the present invention. The method in the embodiment of the present invention is applied to user equipment UE accessing between different access networks. When switching, the selection of the network device including the packet data network gateway PDN GW may specifically be performed by, for example, an HSS, such as a device that performs one or more management including subscription management, authentication management, and location management on the user equipment. The method of the embodiment of the present invention includes:

S301: The first request message sent by the third network device is received, where the first request message is that the third network device receives the indication sent by the user equipment to switch the access network used by the session from the second access network to And sending, by the first access network, a handover request message, where the first request message is used to request to obtain an identifier of the first packet data network gateway used by the user equipment to access the core network by using the second access network. The third network device is a network device that selects a packet data network gateway.

Specifically, the third network device may be a network device such as an MME. The user equipment UE may generate and send a corresponding indication to the user equipment when receiving the network switching instruction of the user, or when detecting that the coverage signal is better than the second access network of the first access network. The access network used by the session is switched by the second access network to the handover request message of the first access network, where the handover request message is specifically used to request a message for performing network handover, for example, if the UE needs to switch from the non-3GPP access network. When the network accesses the 3GPP, the UE sends an attach request message (attach request) to the corresponding MME.

The first request message is a location update request or an authentication request or a gateway update request, and the first response message may be a location update response or an authentication response or a gateway update response, where the first response message is A network device is a home subscription server or an authentication server.

S302: Send a first response message to the third network device, where the first response message carries at least the identifier of the first packet data network gateway, so that the third network device selects The first access point name is used as the access point name used by the session of the user equipment after switching to the first access network, and the packet data network indicated by the identifier of the first packet data network gateway is selected. The gateway is used as the packet data network gateway used by the user equipment after the session is switched to the first access network, where the first access point name is the user equipment through the second access network. An access point name used when accessing the core network, where the first access point name is obtained by the third network device from the handover request message or the first response message, the first packet data network The identifier of the gateway corresponds to the first access point name.

The identifier of the first packet data network gateway in the first response message may be information according to the identifier of the UE, the user information, or the first APN (directly reported by the UE) used by the UE to access the second access network. In the PDN GW identifier that is stored in the local area, the identifier of the PDN GW used by the UE to access the second access network is searched and carried in the first response message and returned to the third network device.

The identifier of the first packet data network gateway that is carried in the first response message may be specifically obtained from the second network device, where the second network device is the second device The authentication server used when accessing the core network. That is, the first network device, such as the HSS, may also obtain the first request message, according to the identifier of the corresponding UE, to the second network device, such as the AAA Server, for performing authentication, authorization, and accounting. The UE accesses the PDN GW identifier used by the first access network, so that the first network device can return the identifier of the corresponding PDN GW according to the first request message.

Before the first network device returns the first response message according to the first request message, the method further includes: determining that the access network used by the user equipment is changed from the second access network to the first access network, specifically :

Determining, according to the first indication information, that the access network used by the user equipment is changed from the second access network to the first access network, where the first indication information indicates that the session is used before the handover. The access network is the second access network or the access network indicating that the session is used is switched from the second access network to the first access network, and the first request message carries the first An indication letter Interest; or,

Determining that the type of radio access technology of the user equipment is changed by the second access network to the first access network, determining that an access network used by the user equipment is changed by the second access network The first access network.

After determining that the access network used by the user equipment is changed from the second access network to the first access network, the corresponding first packet data network gateway is obtained, or information such as the first APN is further acquired. And transmitting, in the first response message, the first PND GW and the first APN to the third network device.

Further, the method for obtaining the first PND GW and the first APN may be: carrying the first access point name in the handover request message, so that the first request message carries the first The access point name, according to the first access point name carried in the first request message, carrying at least the identifier of the first packet data network gateway in the first response message, the first packet The identity of the data network gateway corresponds to the first access point name.

The handover procedure disclosed in the embodiment of the present invention can ensure that the UE continues to use the PDN GW used when accessing the core network through the original access network before switching, after the handover to the new access network, thereby The IP address does not change, and the problem of interruption of the IP data stream transmission of the UE is avoided.

The method for selecting a network device in the handover process of the embodiment of the present invention is described in the following four specific examples.

FIG. 5 is a schematic diagram of a specific process of a method for selecting a network device in a handover process according to an embodiment of the present invention. The method of the embodiment of the present invention is applied to handover of a UE from a non-3GPP TWAN to a 3GPP access network, where the MME is a third network device, and the HSS is a first network device, and the TWAN is a second access network, 3GPP. The E-UTRAN of the access network is the first access network. The method specifically includes:

SI: The UE is connected to the trusted wireless access network TWAN. The UE may establish a PMIPv6 (Proxy Mobile IPv6) or a GTP (GPRS Tunnel Protocol) tunnel through the S2a interface between the PDN GW and the TWAN serving the UE to implement the UE and the TWAN. Connect and establish a session through the corresponding IP address to access data in the core network or through the core network.

S2: The UE detects an E-UTRAN (Evolved Universal Terrestrial Radio Access Network) and decides to switch the current session from the TWAN to the E-UTRAN. Specifically, the user may set the UE to access the core network preferentially through the E-UTRAN in advance. Therefore, when the UE detects the coverage signal corresponding to the E-UTRAN, the process of switching the current session TWAN to the E-UTRAN is initiated. Of course, the UE may initiate a process of switching the current session TWAN to the E-UTRAN when the UE detects that the current E-UTRAN signal coverage is good.

S3: The UE initiates an attach request Attach Request to the MME, where the handover indication Handover indication may be carried to indicate that the access network used by the session of the user equipment is switched from the second access network TWAN to the first access network E-UTRAN .

The receiving the request message sent by the user equipment may be an attach request sent by the UE to the MME in the embodiment of the present invention, and may also be another access network used to indicate the session of the user equipment. Switching from the second access network, such as TWAN, to the first access network, such as E-UTRAN request.

S4: The MME sends a signaling to the HSS to authenticate the UE, that is, the authentication operation includes determining whether the UE is a subscription user, and performing the following S5 after the authentication is passed.

S5: The MME sends an update location request Update Location Request to the HSS. The request message includes a RAT (Radio Access Technology) type, an MME identity, and the like that the UE currently accesses the network, to update the location information of the UE. At this time, the radio access technology type RAT of the current access network is E-UTRAN. The update location request is further used to request the subscription data corresponding to the UE, and specifically includes information such as the subscribed APN and the PDN GW identifier corresponding to the APN.

The first request message sent to the first network device may be the update location request sent by the MME to the HSS in the embodiment of the present invention, and may be used to request the HSS to acquire the UE. A message of the identity of the first PDN GW used by the second access network to access the core network, such as an authentication request or an update gateway request.

The first indication information that is carried in the first request message may be specifically the RAT type of the UE currently accessing the network carried in the update location request message.

S6: The HSS determines that the access network of the UE is changed from the TWAN to the E-UTRAN according to the pre-handover access network information of the locally stored UE, and the RAT in the update location request is E-UTRAN, and may further determine that the UE passes The APN used by the TWAN access is different from the APN accessed by the E-UTRAN. Specifically, the APN used by the UE through the WLAN access may be a default APN or other APN (ie, a non-default APN). Specifically, the pre-handover access network information of the UE stored by the HSS includes at least a RAT type when the UE accesses the TWAN, that is, RAT=WLAN or RAT=TWAN; and the APN used by the UE through the TWAN access may be a default APN.

S7: The HSS replies to the MME with an update location acknowledgment message Update Location ACK, where the message may include the access point name APN used by the UE when accessing the core network through the TWAN, and the PDN GW used by the UE corresponding to the APN when accessing the core network through the TWAN. Identification, access network information and other information before switching. Specifically, the UE included in the message is used by the TWAN access network. The access point name APN may be one or more, including at least a default APN used by the UE to access the network through the TWAN; thus, the message includes an identifier of the PDN GW corresponding to each APN. The PDN GW identifier may be a PDN GW address, or a PDN GW FQDN. In this embodiment, the identifier of the PDN GW is used as a PDN GW address. Specifically, the PDN GW address may be an IP address of the PDN GW. The information of the access network before the handover may include information such as the type of the previous radio access technology. Here, the type of the previous radio access technology is WLAN or TWAN, and may be represented by Previous RAT=WLAN or Previous RAT=TWAN.

The received first response message sent by the first network device may be an update location confirmation message sent by the HSS in the embodiment of the present invention, and may also be other response messages for responding to the request of S5. The information such as the access point name APN used by the UE to access the core network through the TWAN, and the identifier of the PDN GW used by the UE corresponding to the APN to access the core network through the TWAN may be carried.

The second indication information carried in the first response message may be the pre-switching access network information carried in the first response message.

S8: The MME does not provide the APN in the attach request, and the MME selects the information of the access network in the update location confirmation message, for example, the information of the previous radio access technology type is TWAN, and selects the UE in the TWAN access in the update location confirmation message. The PDN GW indicated by the identifier of the PDN GW used by the default APN used by the network and its corresponding UE when accessing the core network through the TWAN is used as the APN and PDN GW used after the current session of the UE is switched to the E-UTRAN.

The following S9 to S21 are the session establishment procedures initiated after the MME obtains the first APN and its corresponding first PDN GW identifier.

S9: The MME sends a setup session request to the S-GW (Serving Gateway). The request message includes the APN selected in step S8 and the address, handover indication, and other information of the corresponding PDN GW.

S10: The S-GW sends a setup session request to the PDN GW according to the PDN GW address in the step S9, where the message includes a handover indication and other information. Sl l : If PCC (Policy and Charging Control) is used in the network, the PDN GW initiates IP to the PCRF (Policy and Charging Rules Function) based on the handover indication. The CAN (Internet Protocol-Connectivity Access Network) session 4 tampering process is performed to obtain the QoS policy and charging rules of the session after the UE switches to the new access network E-UTRAN.

S12: The PDN GW sends a setup session response to the S-GW. According to the handover indication in the setup session request, the PDN GW allocates the same IP address (that is, used by the TWAN access network) to the UE before the handover (including IPv4). The address, or IPv6 prefix), and is carried in the setup session response message.

S13: The S-GW sends a setup session response to the MME, where the IP address of the UE is carried.

S 14: The UE establishes a radio access bearer through the E-UTRAN.

S15: The MME sends a modify bearer request Modify Bearer Request to the S-GW, where the handover indication is carried.

S16: According to the handover indication, the S-GW sends a modify bearer request to the PDN GW, so that the PDN GW transfers the packet data from the TWAN access system to the E-UTRAN, and immediately starts sending packet data to the S-GW.

S17: The PDN GW sends a modify bearer response Modify Bearer Response to the S-GW.

S18: The S-GW sends a modify bearer response to the MME.

S19: The UE starts transmitting and receiving data through the E-UTRAN.

S20: If the UE has multiple PDN connections, the UE then switches the other PDN connections one by one to the E-UTRAN by the TWAN access.

S21: The PDN GW initiates a resource release process to the TWAN access network to release the corresponding bearer resource of the TWAN access.

The embodiment of the invention discloses a process for a complete UE to switch from the second access network to the first access network, and implements the same PDN GW for the UE before and after the access network handover, thereby ensuring The UE can use the same IP address for the session to avoid the interruption of data transmission. Referring to FIG. 6, FIG. 6 is another schematic flowchart of another method for selecting a network device in a handover process according to an embodiment of the present invention. The method of the embodiment of the present invention is applied to handover of a UE from a non-3GPP TWAN to a 3GPP access network, where the MME is a third network device, and the HSS is a first network device, and the TWAN is a second access network, 3GPP. The E-UTRAN of the access network is the first access network. The method specifically includes:

S2: The UE detects the E-UTRAN and decides to switch the current session from the TWAN to the E-UTRAN. Specifically, the user may set the UE to access the core network preferentially through the E-UTRAN in advance. Therefore, when the UE detects the coverage signal corresponding to the E-UTRAN, the process of switching the current session TWAN to the E-UTRAN is initiated. Of course, when the UE detects that the current E-UTRAN signal coverage is good, the UE initiates a process of switching the current session TWAN to the E-UTRAN.

S3: The UE initiates an attach request to the MME, and the message may carry a handover indication Handover indication, an access network information before handover, and other information. Specifically, the information about the access network before the handover may include information such as the type of the previous radio access technology, where the previous radio access technology type is WLAN or TWAN, and may be represented by Previous RAT=WLAN or Previous RAT=TWAN.

The receiving the request message sent by the user equipment may be an attach request sent by the UE to the MME in the embodiment of the present invention, and may also be another access network used to indicate the session of the user equipment. A request by a second access network, such as a TWAN, to a first access network, such as E-UTRAN.

The second indication information carried by the handover request message may be in the attach request message. The handover indication and/or the information about the access network before the handover may be used as the other access network for indicating the use of the session before the handover, or the connection to the session. The access network is switched by the second access network to the information of the first access network.

S5: The MME sends an update location request Update Location Request to the HSS, where the message includes the RAT type of the current access network, the MME identity, and the like, to update the location information of the UE. Here, the RAT type of the current access network is E-UTRAN. The update location request is further used to request subscription data corresponding to the UE, and specifically includes information such as the signed APN and the PDN GW identifier corresponding to the APN.

The MME does not provide the APN in the attach request. Optionally, the MME carries an indication, such as a handover indication or an indication of handover from the WLAN, in the update location request according to the handover indication and the previous radio access technology type information in the attach request. In order for the HSS to return the APN used by the UE to access the network through the WLAN according to this indication.

The first request message sent to the first network device may be the update location request sent by the MME to the HSS in the embodiment of the present invention, and may be used to request the HSS to acquire the UE. A message of the identity of the first PDN GW used by the second access network to access the core network, such as an authentication request or an update gateway request. The first indication information that is carried in the first request message may be a handover indication carried in the update location request message or an indication of handover from the WLAN, so that the HSS returns the UE to access the network through the WLAN according to the indication. The APN used.

S6: The HSS determines that the access network of the UE is changed from the WLAN to the E-UTRAN, and the APN used by the UE through the WLAN access is different from the APN accessed by the 3GPP. Specifically, the UE passes the specific: the HSS may determine, according to the pre-handover access network information of the locally stored UE, the RAT in the update location request is E-UTRAN, and determine that the access network of the UE is changed from WLAN to E-UTRAN; and/or, according to the indication carried in the update location request, such as the handover indication or the indication of handover from the WLAN, according to S5, determining that the access network of the UE is changed from WLAN to E-UTRAN. The pre-handover access network information of the UE stored by the HSS includes at least the RAT type when the UE accesses the TWAN, that is, RAT=WLAN or RAT=TWAN.

S7: The HSS replies to the MME with an update location confirmation message Update Location ACK. The update location confirmation message carries the APN used by the UE to access the core network through the TWAN, and the PDN GW identifier used by the UE corresponding to the APN to access the core network through the TWAN.

Specifically, the access point name APN used by the UE in the update location confirmation message to access the network through the TWAN may be one or more, where at least the default APN used by the UE to access the network through the TWAN is included; The identifier of the PDN GW corresponding to the APN. The PDN GW identifier may be a PDN GW address or a PDN GW FQDN. In this embodiment, the identifier of the PDN GW is a PDN GW address.

S8: The MME selects the default APN used by the UE in the update location confirmation message to access the network through the trusted WLAN, according to the handover indication in the attach request and/or the access network information before the handover. The PDN GW indicated by the identifier of the PDN GW used by the UE and the corresponding UE to access the core network through the TWAN is used as the APN and the PDN GW used after the current session of the UE is switched to the E-UTRAN.

S9: The MME sends a setup session request Create Session Request to the S-GW, where the message includes the APN determined in S8 and the address of the corresponding PDN GW, the handover indication, and other information. Interest.

S10: The S-GW sends a setup session request to the PDN GW according to the PDN GW address in S9, where the message includes a handover indication and other information.

S11. If PCC (Policy and Charging Control) is adopted in the network, the PDN GW initiates IP-CAN to the PCRF (Policy and Charging Rules Function) according to the handover indication. (Internet Protocol-Connectivity Access Network) The session 4 tampering process to obtain the policy and charging rules of the session quality of service QoS after the UE switches to the new access network E-UTRAN.

S13: The S-GW sends a setup session response to the MME, where the IP address of the UE is carried. S14: The UE establishes a radio access bearer through the E-UTRAN.

S18: The S-GW sends a modify bearer response to the MME.

S19: The UE starts transmitting and receiving data through the E-UTRAN.

S21: The PDN GW initiates a resource release process to the TWAN access network to release the TWAN connection. Enter the corresponding bearer resource.

The embodiment of the present invention discloses a process for a complete UE to switch from the second access network to the first access network, and implements the same PDN GW for the UE before and after the access network handover, thereby ensuring that the UE can use the same IP address. Conduct a session to avoid data transfer interruptions.

Referring to FIG. 7, FIG. 7 is another schematic flowchart of a method for selecting a network device in a handover process according to an embodiment of the present invention. Similarly, the method in this embodiment includes the UE switching from the TWAN of the non-3GPP network to the E-UPRAN of the 3GPP network, where the MME is the third network device, and the HSS is the first network device, and wherein the 3GPP AAA is The server is the second network device, the TWAN is the second access network, and the E-UTRAN of the 3GPP access network is the first access network. The method specifically includes:

S3: The UE initiates an attach (ie, registration) request to the MME, and the message may carry the handover indication, and may also carry the APN, and is used to indicate that the UE requests to establish (or switch) a PDN connection corresponding to the APN, and the APN may be the default. APN or other APN (ie non-default APN).

The receiving the request message sent by the user equipment may be the attach request sent by the UE to the MME according to the embodiment of the present invention, and may be used for indicating the use. The access network used by the session of the user equipment is switched by the second access network, such as the TWAN, to the request message of the first access network, such as E-UTRAN.

The second indication information carried in the handover request message may specifically be the handover indication carried in the attach request, and may be another access network used to indicate the use of the session before the handover as the second An access network or information indicating that an access network used by the session is switched from the second access network to the first access network.

S5: The MME sends an update location request Update Location Request to the HSS, where the message includes the RAT of the current access network, the MME identity, and the like, to update the location information of the UE. At this time, the RAT of the current access network is E-UTRAN, that is, RAT=E-UTRAN. The update location request message may also carry a handover indication and an APN provided by the UE in the attach request message. The update location request is further used to request the subscription data corresponding to the UE, and specifically includes information such as the subscribed APN and the PDN GW identifier corresponding to the APN.

The first indication message that is carried in the first request message may be the handover indication carried in the first request message and/or the RAT type of the UE currently accessing the network.

S6: The HSS determines that the access network of the UE is changed from the WLAN to the E-UTRAN, and further, it may be determined that the APN used by the UE through the WLAN access is different from the APN accessed by the 3GPP, or the UE accesses the core network through the WLAN and passes the 3GPP. The APN used by the access network to access the core network is the same but the PDN GW corresponding to the APN may be different. Specifically, the UE connects to the default APN or other APN through the WLAN (ie, non-default)

Specific: The HSS can be based on the locally stored UE's pre-switching access network information, and updated. The RAT in the location request is the E-UTRAN, and the access network of the UE is determined to be changed from the WLAN to the E-UTRAN. The access network carried in the update location request may further be determined to change the access network of the UE from the WLAN to the E-UTRAN. . The pre-handover access network information of the UE stored by the HSS includes at least the RAT type when the UE accesses the TWAN, that is, RAT=WLAN or RAT=TWAN.

S7: The HSS sends an update packet data network gateway identifier trigger message to the 3GPP AAA Server. The Update PDN GW Identity Trigger is used to trigger the 3GPP AAA Server to update the identifier of the packet data network gateway used by the UE to access the core network through the TWAN. The packet data network gateway identifier trigger message carries the user identifier; the APN that is used by the locally stored UE to access the network through the WLAN, or the APN provided by the MME in the update location request message. Specifically, the user identifier in the update packet data network gateway identifier trigger message is an IMSI (International Mobile Subscriber Identification Number).

S8: The 3GPP AAA Server sends an Update Packet Data Network Gateway Identity Request message Update PDN GW Identity Request to the HSS, where the APN carrying the UE when the TWAN access network accesses the core network and its corresponding PDN GW identifier are carried; or according to the update packet The data network gateway identifies the APN in the trigger message, and carries the PDN GW identifier corresponding to the APN when the UE accesses the core network through the TWAN.

S9: The HSS sends an update packet data network gateway identity confirmation message Update PDN GW Identity ACK to the 3GPP AAA Server.

S10: The HSS replies to the MME with an update location confirmation message Update Location ACK. The update location confirmation message includes the PDN GW identifier received by the HSS in step 8, and may also include an APN used by the UE to access the core network through the TWAN, where at least one APN corresponds to the PDN GW identifier received by the HSS in step S8. . Specifically, the APN corresponding to the PDN GW identifier received by the HSS in step S8 may be the default APN used when the UE accesses the core network through the TWAN access network, or the same APN as the APN provided by the UE in the attach request. (If the UE provides an APN in the attach request).

S1: The MME selects, according to the APN and the handover indication provided by the UE in the attach request, the PDN GW indicated by the identifier of the PDN GW used by the UE corresponding to the APN in the update location confirmation message to access the core network through the TWAN. The PDN GW used by the UE after the current session is handed over to the E-UTRAN. If the UE does not provide the APN in the attach request, the MME selects the default APN used by the UE in the update location confirmation message to access the core network through the TWAN, and the PDN GW identifier corresponding to the default APN received by the HSS in step S8. The APN and PDN GW used by the UE after the current session is switched to the E-UTRAN.

It should be noted that, if the UE has established a PDN connection of the same APN in the E-UTRAN access network before the handover, and uses a different PDN GW, the MME may select the APN in the E-UTRAN access network according to the operator policy. Corresponding PDN GW. In this way, the PDN connection of the APN switched to the 3GPP by the WLAN will use different PDN GWs, the IP address will change, and the IP service cannot be seamlessly switched; but other benefits can be brought about, for example, avoiding the same APN using two Or additional bandwidth usage caused by multiple PDN GWs.

The following S12 to S24 are the session establishment procedures initiated after the MME obtains the first APN and its corresponding first PDN GW identifier.

S12: The MME sends a setup session request Create Session Request to the S-GW, where the message includes the APN and PDN GW addresses determined in the Sl, the handover indication, and other information.

S13: The S-GW sends a setup session request to the PDN GW according to the PDN GW address in the establishment session request, where the message includes a handover indication and other information.

S 14: If PCC (Policy and Charging Control) is adopted in the network And the charging control;), according to the handover indication, the PDN GW initiates an IP-CAN (Internet Protocol-Connectivity Access Network) session to the PCRF (Policy and Charging Rules Function) The tampering process is to obtain the QoS policy and charging rules of the session after the UE switches to the new access network E-UTRAN.

S15: The PDN GW sends a session establishment response Create Session Response to the S-GW. According to the handover indication in the establishment of the session request, the PDN GW allocates the same IP address (including the IPv4 address or the IPv6 prefix) that the UE uses before the handover (that is, the T4), and carries the session response message.

S16: The S-GW sends a setup session response to the MME, where the IP address of the UE is carried. S17: The UE establishes a radio access bearer through the E-UTRAN.

S18: The MME sends a modify bearer request Modify Bearer Request to the S-GW, where the handover indication is carried.

S19: According to the handover indication, the S-GW sends a modify bearer request to the PDN GW, so that the PDN GW transfers the packet data from the TWAN access system to the E-UTRAN, and immediately starts sending packet data to the S-GW.

S20: The PDN GW sends a modify bearer response Modify Bearer Response to the S-GW.

S21: The S-GW sends a ^ί'爹 to the MME to change the response.

S22: The UE starts to send and receive data through the E-UTRAN.

S23: If the UE has multiple PDN connections, the UE then switches the other PDN connections one by one to the E-UTRAN by the TWAN access.

S24: The PDN GW initiates a resource release process to the TWAN access network to release the corresponding bearer resource of the TWAN access.

It should be noted that, if the MME selects a PDN GW different from the PDN GW that the WLAN accesses before the handover, for example, S11, the UE has established the PDN connection of the same APN in the 3GPP access network before the handover, and uses different When the PDN GW is established, the handover request indication will not be carried in the establishment session request message. Subsequent session establishment steps with existing EPS (Evolved Packet) System, Evolved Packet (Communication) System) The subsequent steps in the attach procedure for the MME to send a setup session request to the S-GW and not including the handover indication.

The embodiment of the present invention discloses a process for a complete UE to switch from the second access network to the first access network, and selects the same PDN GW for the UE before and after the access network handover, thereby ensuring that the UE can use the same IP. The address is in session to avoid a data transmission interruption.

Referring to FIG. 8, FIG. 8 is a schematic diagram of still another specific process of the method for selecting a network device in a handover process according to an embodiment of the present invention. The method of this embodiment includes the UE switching from the TWAN of the non-3GPP network to the E-UPRAN of the 3GPP network, where the MME is the third network device, and the HSS is the first network device, and the 3GPP AAA Server is The second network device, the TWAN is the second access network, and the E-UTRAN of the 3GPP access network is the first access network. The method specifically includes:

S3: The UE sends an attach request to the MME, and the message may carry the handover indication, and the message may also carry the APN, and the message may be used to indicate that the UE requests to establish (or switch) the handover request message sent by the receiving user equipment. The embodiment of the invention An attach request sent by the UE to the MME. Of course, other access networks for indicating the use of the session of the user equipment may be switched from a second access network, such as a TWAN, to a first access network, such as an E-UTRAN. Request message.

The second indication information may be the handover indication carried in the attach request, and may be another access network for indicating the use of the session before the handover as the second access network or indication. The access network used by the session is switched by the second access network into information of the first access network.

S5: The MME sends an update location request Update Location Request to the HSS, where the message includes the RAT, the MME identity, and the like of the current access network, to update the location information of the UE. At this time, the RAT of the current access network is E-UTRAN, that is, RAT=E-UTRAN. The HSS returns information such as subscription data to the MME. It should be noted that this step is the same as the process in which the existing MME updates the UE location and acquires the subscription data to the HSS.

S6: The MME selects the PDN GW-2 according to the subscription data and the attach request of the UE, and sends a setup session request to the S-GW, where the handover indication and the address of the PDN GW-2 are carried.

S7: The S-GW sends a setup session request to the PDN GW-2, where the handover indication is carried. That is, the MME selects the second packet data according to the second access point name subscribed by the user equipment in the E-UTRAN and the identifier of the second packet data network gateway corresponding to the second access point name in the E-UTRAN. And the network gateway sends a setup session request message to the second packet data network gateway.

S8: The PDN GW-2 cannot identify the handover indication in the establishment session request, and therefore sends a setup session reply message to the S-GW, which carries the reason for the rejection or failure, indicating that the handover cannot be performed, for example: 3⁄4 port Cause=invalid handover indication (reason) = invalid switching indication).

The message sent by the second packet data network gateway indicating that the session establishment failure or the handover failure is performed may be specifically that the PDN GW-2 in the embodiment of the present invention sends a session establishment session to the S-GW. The complex message can of course also be a message carrying the reason for the rejection or failure, indicating that the handover cannot be performed or the session is failed.

S9: The S-GW forwards the session reply to the MME.

S10: The MME sends a gateway update request to the HSS to request a new PDN GW. The gateway update request may carry an indication, such as "handover cannot be performed" or "request new PDN GW" indication, and may also carry other information, such as: user identity (ie, IMSI), APN, PDN GW-2 identity, and the like. Specifically, the gateway update request may be a notification request Notify Request, or another message for requesting to update the packet data network gateway to implement handover.

The first request message sent to the first network device may be the gateway update request sent by the MME to the HSS in the embodiment of the present invention, and may be used to request the HSS to acquire the UE. A message of the identity of the first PDN GW used when the second access network accesses the core network.

The first indication information carried in the first request message may be an indication of "switching cannot be performed" or "requesting a new PDN GW" in the first request message.

Sl l: The HSS may determine that the access network of the UE is changed from the WLAN to the E-UTRAN according to the pre-handover access network information of the locally stored UE, and/or the gateway update request, and may further determine that the UE accesses through the WLAN. The used APN is different from the APN accessed by the 3GPP, or the UE accessing the core network through the WLAN is the same as the APN used by the 3GPP access network to access the core network, but the PDN GW corresponding to the APN may be different. Specifically, the APN used by the UE through the WLAN access may be a default APN or other APN (ie, a non-default APN). The pre-handover access network information of the UE stored by the HSS includes at least the RAT type when the UE accesses the TWAN, that is, RAT=WLAN or RAT=TWAN.

The PDN GW Identity Trigger, which carries the user identifier (ie, IMSI), may also carry the locally stored APN used by the UE to access the network through the WLAN, or the APN provided by the MME in the notification request message in step S8. S13: The 3GPP AAA Server sends an Update PDN GW Identity Request message Update PDN GW Identity Request to the HSS, where the APN and the corresponding PDN GW identifier of the UE when the UE accesses the core network by the TWAN access network are carried, or the PDN GW identifier is updated according to the update The APN in the trigger message carries the PDN GW identifier corresponding to the APN when the UE accesses the core network through the TWAN. That is, the identifier of the first APN and the corresponding first PDN GW.

Interest Update

PDN GW Identity ACK:.

S15: The HSS replies to the MME with a gateway update response, where the message carries the PDN GW identifier received by the HSS at S13, and may also carry the APN used by the UE to access the core network through the TWAN, where at least one APN and the HSS are received in step S13. The PDN GW logo corresponds. Specifically, the APN corresponding to the PDN GW identifier received by the HSS in step S13 may be a default APN used when the UE accesses the core network through the TWAN access network, or an APN that is the same as the APN provided by the UE in the attach request. (If the UE provides an APN in the attach request). Specifically, the gateway update response may be a notification response Notify Answer, or other message for providing a new packet data network gateway identifier to implement the handover.

The received first response message sent by the first network device may be a notification response of the HSS reply in the embodiment of the present invention, and may also be another response message for responding to the request of S10, where The information such as the access point name APN used by the UE to access the core network through the TWAN, and the identifier of the PDN GW used by the UE corresponding to the APN to access the core network through the TWAN may be carried.

The following S16 to S28 are the session establishment procedures initiated after the MME obtains the first APN and its corresponding first PDN GW identifier.

S16: The MME selects the PDN GW-1 according to the PDN GW identifier in the notification response, and sends a setup session request to the S-GW, where the APN, the handover indication, and the address of the PDN GW-1 are carried.

S17: The S-GW sends a setup session request to the PDN GW-1, where the handover indication is carried.

S18: If PCC (Policy and Charging Control) is adopted in the network And the charging control), according to the handover indication, the PDN GW-1 initiates an IP-CAN (Internet Protocol-Connectivity Access Network) session to the PCRF (Policy and Charging Rules Function) 4 tampering process to obtain the QoS policy and charging rules of the session after the UE switches to the new access network E-UTRAN.

S19: The PDN GW-1 sends a session establishment response to the S-GW, Create Session Response. According to the handover indication in establishing the session request, the PDN GW-1 allocates the same IP address (including the IPv4 address or the IPv6 prefix) that the UE is used before the handover (that is, used in the TWAN access network), and carries the session response message. in.

S20: The S-GW sends a setup session response to the MME, where the IP address of the UE is carried. S21: The UE establishes a radio access bearer through the E-UTRAN.

S22: The MME sends a modify bearer request Modify Bearer Request to the S-GW, where the handover indication is carried.

S23: According to the handover indication, the S-GW sends a modify bearer request to the PDN GW, so that the PDN GW-1 transfers the packet data from the TWAN access system to the E-UTRAN, and immediately starts sending packet data to the S-GW.

S24: The PDN GW sends a modify bearer response Modify Bearer Response to the S-GW.

S25: The S-GW sends a modify bearer response to the MME.

S26: The UE starts transmitting and receiving data through the E-UTRAN.

S27: If the UE has multiple PDN connections, the UE then switches the other PDN connections one by one to the E-UTRAN by the TWAN access.

S28: The PDN GW initiates a resource release process to the TWAN access network to release the corresponding bearer resource of the TWAN access.

The device for selecting a network device in the handover process of the embodiment of the present invention is described in detail below. Said.

Referring to FIG. 9, FIG. 9 is a schematic structural diagram of an apparatus for selecting a network device in a handover process according to an embodiment of the present invention. The device of the embodiment of the present invention may be disposed in a device having a network device selection function, such as an MME, where the device includes:

The handover request message receiving unit 11 is configured to receive, by the user equipment, a handover request message indicating that the access network used by the session of the user equipment is switched from the second access network to the first access network;

The first obtaining unit 12 is configured to acquire a first access point name used by the user equipment to access the core network through the second access network;

The second obtaining unit 13 is configured to acquire, from the first network device, a first packet data network gateway corresponding to the first access point name used by the user equipment to access the core network by using the second access network. And the first network device is a network device that manages the user equipment by the network side, where the management is: one or more of subscription management, authentication management, and location management; Selecting the first access point name acquired by the acquiring unit as the access point name used after the session of the user equipment is switched to the first access network, and selecting the first group acquired by the acquiring unit The packet data network gateway indicated by the identifier of the data network gateway is used as a packet data network gateway used after the session of the user equipment is switched to the first access network.

The user equipment UE may generate and send a corresponding indication to the user equipment when receiving the network switching instruction of the user, or when detecting that the coverage signal is better than the second access network of the first access network. The access network used by the session is switched by the second access network to a handover request message of the first access network, where the handover request message is specifically used to request a message for performing network handover, and the handover request message receiving unit 11 receives the message. When the request message is switched, the device selection operation is performed.

The first network device is a network device that manages the user equipment on the network side, such as a home subscription server HSS or an authentication server, and the management is: one of subscription management, authentication management, and location management. A variety. When the UE accesses the core network through the second access network, A network device allocates and manages an APN allocated to the UE and a used PDN GW.

The first access point name obtained by the first acquiring unit 12 may be directly obtained from the handover request message, that is, the UE may carry the user equipment through the second in the handover request message. The name of the first access point used by the access network to access the core network; that is, the name of the first access point may be directly reported by the user equipment. Or the first access point name may be obtained from the first network device, and the first access point name used by the user equipment when accessing the core network by using the second access network may be The information such as the identifier of the device UE is obtained after requesting the search in the first network device such as the HSS.

The second obtaining unit 13 obtains the identifier of the first packet data network gateway, that is, the first PDN GW, and after obtaining the first APN of the UE, the second acquiring unit 13 obtains the corresponding number according to the APN to the first network device. The identity of a PDN GW. Certainly, in other embodiments, the identifier of the user equipment UE may also be obtained from a first network device, such as an HSS, where the identifier of the first PDN GW may be a first PDN GW address, or a PDN GW FQDN (Fully Qualified) Domain Name, full name domain name, etc.

The UE accesses the first access network through the APN and the PDN GW used in the second access network, thereby implementing access to the core network for various types of data access, interaction, and the like.

Further, the selecting unit 14 may be configured to: select, according to the second indication information, the first access point name as the connection used by the user equipment after the session is switched to the first access network. a point data name, the packet data network gateway indicated by the identifier of the first packet data network gateway is selected as a packet data network gateway used by the user equipment to switch to the first access network, where The second indication information indicates that an access network used by the session before handover is the second access network or an access network indicating that the session is used is switched from the second access network to the first The access network, the handover request message and/or the first response message carries the second indication information.

Further, as shown in FIG. 10, the second acquiring unit 13 in FIG. 9 may specifically include: a first request message sending sub-unit 131, configured to send a first request message to the first network device, where the first request message is used to request that the user equipment access the core network through the second access network The identifier of the first packet data network gateway used at the time;

The first response message receiving sub-unit 132 is configured to receive, after the first request message sending sub-unit sends the first request message, the first response message sent by the first network device, where the first response message is at least And carrying the identifier of the first packet data network gateway, where the identifier of the first packet data network gateway corresponds to the first access point name.

The first request message is a location update request or an authentication request or a gateway update request, and the first response message is a location update response or an authentication response or a gateway update response, and the first network device is a home subscription server. Or authentication server.

The first request message sent by the first request message sending sub-unit 131 may include the identifier or user information of the UE or the first APN (directly reported by the UE) used by the UE to access the second access network, etc., so that The first network device, such as the HSS, can search for the PDN GW identifier used by the UE when accessing the second access network, and return the found PDN GW identifier in the locally stored PDN GW identifier.

Further, the first request message sent by the first request message sending sub-unit 131 carries the first indication information, so that the first network device determines, according to the first indication information, the connection used by the user equipment. Step of performing the sending of the first response message after the second access network is changed to the first access network, where the first indication information indicates that the access network used by the session before the handover is Said second access network or an access network indicating the use of said session is switched from said second access network to said first access network.

Further, the identifier of the first packet data network gateway acquired by the second acquiring unit 13 is specifically acquired by the first network device from the second network device, where the second network device is the user equipment The authentication server used when the access network accesses the core network.

The identifier of the first packet data network gateway is specifically obtained by the first network device from a second network device, where the second network device is accessed by the user equipment by using the second access network The authentication server used by the core network. That is, the first network device, such as the HSS, may also obtain the first network request from the second network device, such as the AAA Server, for authentication, authorization, and accounting, according to the identifier of the corresponding UE when receiving the first request message. The UE accesses the PDN GW identifier used by the first access network, so that the first network device can return the identifier of the corresponding PDN GW according to the first request message.

In addition, the first acquiring unit 12 is specifically configured to acquire the first access point name from the handover request message, where the handover request message carries the user equipment to access the core through the second access network. The first access point name used by the network when the network device accesses the core network through the second access network is obtained from the first network device.

Further, the handover request message may further carry the first access point name, so that the first request message carries the first access point name, so that the first network device is configured according to the first The first request message acquires an identifier of the first packet data network gateway corresponding to the first access point name.

The embodiment of the present invention discloses a process for a complete UE to switch from the second access network to the first access network. In the process of the embodiment, the UE selects the same before and after the access network handover through a new interaction mode. A PDN GW, so that the UE can use the same IP address for the session to avoid the occurrence of data transmission interruption.

Referring to FIG. 11, FIG. 11 is a schematic structural diagram of a device for selecting a network device in another handover process according to an embodiment of the present invention. The device in the embodiment of the present invention may be disposed in a device having a network device selection function, such as an MME, including the foregoing handover request message receiving unit 11, the first obtaining unit 12, the second obtaining unit 13, and the selecting unit 14, and further The device further includes:

a session establishment message sending unit 15 , configured to: after the switching request message receiving unit receives the switching request message, before the second obtaining unit acquires the identifier of the first packet data network gateway, according to the User equipment signing the second in the first access network The access point name and the identifier of the second packet data network gateway corresponding to the second access point name in the first access network select a second packet data network gateway, and send the second packet data network gateway to the second packet data network gateway Establish a session request message;

The executing unit 16 is configured to: after receiving the message that the second packet data network gateway sends a session failure or a handover failure, notify the second acquiring unit 13 to acquire the user equipment from the first network device by using the The identifier of the first packet data network gateway corresponding to the first access point name used by the access network to access the core network.

In the embodiment of the present invention, after the handover request message receiving unit 11 receives the handover request message sent by the UE indicating that the access network used by the session is switched from the second access network to the first access network, the second Before the obtaining unit 13 acquires the identifier of the first packet data network gateway corresponding to the first access point name from the first network device, the execution unit 16 first directly obtains the PDN GW by using the setup session request message sending unit 15 described above. In the case that the session connection is unsuccessful according to the identifier of the PDN GW, the first obtaining unit 12 and the second obtaining unit 13 perform corresponding operations.

That is, the UE initiates the connection establishment process of the UE to the access network by assigning a new APN and a PDN GW. After the connection establishment is unsuccessful, the UE is disclosed by the embodiment of the present invention. The process of obtaining the network device such as the PDN GW used in the original access network ensures that the IP address does not change after the UE switches to another access network, thereby avoiding the problem that the IP data stream transmission of the UE is interrupted.

Referring to FIG. 12, it is a schematic structural diagram of a device for selecting a network device in another handover process according to an embodiment of the present invention. The device in the embodiment of the present invention may be configured in a network device that manages the user equipment, such as a home subscription server, an HSS, or an authentication server. Specifically, the device includes:

The first request message receiving unit 21 is configured to receive a first request message sent by the third network device, where the first request message is an access network that is sent by the third network device to receive the indication sent by the user equipment. Switching from the second access network to the handover request message of the first access network The first request message is used to request the identifier of the first packet data network gateway used by the user equipment to access the core network through the second access network, where the third network device is a selected group Network device of the data network gateway;

The first response message sending unit 22 is configured to send a first response message to the third network device, where the first response message carries at least the identifier of the first packet data network gateway, so that the third network The device selects the first access point name as the access point name used by the session of the user equipment after switching to the first access network, and selects the group indicated by the identifier of the first packet data network gateway. The data network gateway is used as the packet data network gateway used by the user equipment to switch to the first access network, where the first access point name is the user equipment through the second connection The name of the access point used when the network accesses the core network, where the first access point name is obtained by the third network device from the handover request message or the first response message, the first packet The identity of the data network gateway corresponds to the first access point name.

The first request message in the first request message receiving unit 21 is a location update request or an authentication request or a gateway update request, and the first response message may be a location update response or an authentication corresponding to the first request message. In response to the gateway or the gateway update response, the first network device is a home subscription server or an authentication server.

The identifier of the first packet data network gateway in the first response message may be based on the identifier of the UE, the user information, or the first APN used by the UE to access the second access network. In the locally stored PDN GW identifier, the identifier of the PDN GW used by the UE to access the second access network is searched and carried in the first response message and returned to the third network device. .

Further, the device further includes:

a determining unit 23, configured to determine, before the first response message sending unit 22 sends the first response message, that an access network used by the user equipment is changed from the second access network to the first interface Network access. The determining unit 23 is specifically configured to: before the first response message sending unit 22 sends the first response message, determine, according to the first indication information, at least the access network used by the user equipment by the second connection The access network becomes the first access network, where the first indication information indicates that the access network used by the session before the handover is the second access network or an access network indicating that the session is used. Switching to the first access network by the second access network, the first request message carries the first indication information; or, the first response message sending unit 22 sends the first response Before the message, determining that the type of the radio access technology of the user equipment is changed by the second access network to the first access network, determining that the access network used by the user equipment is used by the second access The network becomes the first access network.

Further, the identifier of the first packet data network gateway that is carried in the first response message may be obtained by the second network device, where the second network device is the second The authentication server used by the access network to access the core network. The identifier of the first packet data network gateway that is included in the first response message includes: the first ringtone The first access point name and the identifier of the first packet data network gateway are carried in the message. Further, the handover request message may further carry the first access point name, so that the first request message carries the first access point name, and is carried according to the first request message. The first access point name carries at least the identifier of the first packet data network gateway in the first response message, and the identifier of the first packet data network gateway is related to the name of the first access point correspond.

Further, the determining unit 23 of the device is further configured to:

Before the first response message sending unit 22 sends the first response message, determining, by using the first access point name used by the user equipment to access the core network by using the second access network, The second access point name used by the user equipment when accessing the core network through the first access network is different; or

Before the first response message sending unit 22 sends the first response message, determine the first access point name used by the user equipment to access the core network through the second access network, and the user equipment The second access point name used by the first access network to access the core network is the same, but the identifier of the first packet data network gateway and the user equipment access the core through the first access network The identifier of the second packet data network gateway used by the network is different, and the identifier of the second packet data network gateway corresponds to the second access point name.

When the UE switches between the access networks, the network device such as the PDN GW used in the original access network can be obtained through the process disclosed in the embodiment of the present invention, and the IP address does not change after the UE switches to another access network. The problem of interruption of the IP data stream transmission of the UE is avoided.

In other embodiments of the present invention, there is also provided a computer storage medium, the computer storage medium storing a program, the program being executed comprising an embodiment of the method corresponding to any of the above Figures 1 to 8.

In other embodiments of the invention, a network device is also provided. FIG. 13 is a schematic structural diagram of a network device according to an embodiment of the present invention. The network device in the embodiment of the present invention may be a device having a network device selection function, such as an MME. Specifically, the network The device includes: a transmitter 100, a receiver 200, and a processor 300, wherein the processor 300 performs the following steps:

Controlling, by the receiver 200, a handover request message sent by the user equipment to change the access network used by the session of the user equipment from the second access network to the first access network;

Acquiring the first access point name used by the user equipment when accessing the core network by using the second access network, and acquiring, by the first network device, the user equipment accessing the core network through the second access network The identifier of the first packet data network gateway that is used by the first access point name, where the first network device is a network device that manages the user equipment by the network side, and the management is: subscription management, One or more of authentication management and location management;

Selecting the first access point name as the access point name used by the session of the user equipment after switching to the first access network, and selecting the group indicated by the identifier of the first packet data network gateway The data network gateway switches to the packet data network gateway used after the first access network as the session of the user equipment.

Further, the processor 300 performs, by acquiring, by the first network device, a first packet data network corresponding to the first access point name used by the user equipment to access the core network through the second access network. The steps of identifying the gateway include:

Controlling the transmitter 100 to send a first request message to the first network device, where the first request message is used to request to acquire the first used by the user equipment to access the core network through the second access network. The identity of the packet data network gateway;

The receiver 200 is configured to receive the first response message sent by the first network device, where the first response message carries at least the identifier of the first packet data network gateway, and the identifier of the first packet data network gateway Corresponding to the first access point name.

The processor 300 controls the transmitter 100 to send a first request message to the first network device as a location update request or an authentication request or a gateway update request, where the first response message is a location update response or a reference. The right response or the gateway update response, the first network device is a home subscription server or an authentication server. Further, the processor 300 further performs the following steps:

The identifier of the first packet data network gateway acquired by the processor 300 is specifically acquired by the first network device from the second network device, and the second network device is the second The authentication server used by the access network to access the core network.

Further, the processor 300 performs the selecting the first access point name as the access point name used by the session of the user equipment after switching to the first access network, and selecting the first The step of the packet data network gateway indicated by the identifier of the packet data network gateway as the packet data network gateway used after the session of the user equipment is switched to the first access network is specifically:

Further, the processor 300 performs the acquiring the user equipment by using the second The name of the first access point used when the access network accesses the core network is specifically:

The processor 300 controls the switch request message received by the receiver 200 to carry the first access point name, so that the first request message carries the first access point name, and further So that the first network device acquires an identifier of the first packet data network gateway corresponding to the first access point name according to the first request message.

The processor 300 performs the step of transmitting, by the receiving user equipment, a handover request message indicating that the access network used by the session is switched from the second access network to the first access network, from the first Before the step of acquiring, by the network device, the identifier of the first packet data network gateway corresponding to the first access point name, performing the following steps:

And the identifier of the second packet data network gateway corresponding to the second access point name in the first access network according to the second access point name that is subscribed by the user equipment in the first access network Selecting a second packet data network gateway, and sending a setup session request message to the second packet data network gateway;

The processor 300 controls the first response message received by the receiver 200 to be specifically sent by the first network device in the following situation:

Determining, by the user equipment, the first access point name used when the user equipment accesses the core network by using the second access network, and the second used by the user equipment when accessing the core network by using the first access network Access point name is different; or, Determining, by the user equipment, the first access point name used when accessing the core network by using the second access network, and the second access used by the user equipment when accessing the core network by using the first access network The point name is the same, but the identifier of the first packet data network gateway is different from the identifier of the second packet data network gateway used by the user equipment when accessing the core network by using the first access network, and the second group is different. The identity of the data network gateway corresponds to the second access point name.

In the embodiment of the present invention, the device having the network device selection function on the network side, such as the MME, selects the same gateway device as the PDN GW before the handover, so as to ensure that the UE is switched from the old access network to the new access network. Ability to continue to use the same IP address for sessions to avoid data transfer interruptions.

In other embodiments of the invention, another network device is also provided. FIG. 14 is a schematic structural diagram of another network device according to an embodiment of the present invention. The network device in the embodiment of the present invention may be a device that manages the user equipment on the network side, such as an HSS. The network device of the embodiment of the present invention includes: a transmitter 400, a receiver 500, and a processor 600, where the processor 600 performs the following Steps:

Controlling the receiver 500 to receive the first request message sent by the third network device, where the first request message is that the third network device receives the indication sent by the user equipment to use the access network used by the session by the second connection. After the network access is switched to the handover request message of the first access network, the first request message is used to request to acquire the first packet data used by the user equipment to access the core network through the second access network. An identifier of the network gateway, where the third network device is a network device that selects a packet data network gateway;

Controlling the transmitter 400 to send a first response message to the third network device, where the first response message carries at least the identifier of the first packet data network gateway, so that the third network device selects the first The access point name is used as the access point name used by the user equipment after the session is switched to the first access network, and the packet data network gateway indicated by the identifier of the first packet data network gateway is selected as The session of the user equipment is switched to the first a packet data network gateway used after accessing the network, where the first access point name is an access point name used by the user equipment to access the core network through the second access network, the first The access point name is obtained by the third network device from the handover request message or the first response message, and the identifier of the first packet data network gateway corresponds to the first access point name.

The processor 600 controls the first request message received by the receiver 500 to be a location update request or an authentication request or a gateway update request, where the first response message is a location update response or an authentication response or a gateway. Updating the response, the third network device is a network device that selects a packet data network gateway.

Further, before the step of controlling the transmitter 400 to send the first response message to the third network device, the processor 600 further includes the following steps:

Determining that the access network used by the user equipment is changed from the second access network to the first access network, specifically: determining, according to at least the first indication information, that the access network used by the user equipment is The second access network becomes the first access network, where the first indication information indicates that the access network used by the session before the handover is the second access network or indicates that the session is used. The access network is switched by the second access network to the first access network, and the first request message carries the first indication information; or, by determining the type of the radio access technology of the user equipment, The second access network is changed to the first access network, and the access network used by the user equipment is determined to be changed from the second access network to the first access network.

Further, the processor 600 controls that the identifier of the first packet data network gateway carried in the first response message sent by the transmitter 400 is specifically acquired from a second network device, where the second network The device is an authentication server used when the user equipment accesses the core network through the second access network.

Further, the processor 600 is configured to control the identifier of the first packet data network gateway in the first response message sent by the transmitter 400, where: the first response message carries the first interface The entry name and the identity of the first packet data network gateway.

Further, the processor 600 further performs the following steps: Carrying the first access point name in the handover request message, so that the first request message carries the first access point name, according to the first carried in the first request message. And an identifier of the first packet data network gateway, where the identifier of the first packet data network gateway corresponds to the first access point name.

Further, the processor 600 controls the transmitter 400 to perform the following steps before the step of sending the first response message to the third network device:

In the embodiment of the present invention, the device that performs the subscription management and/or the authentication management and/or the location management on the network device, such as the HSS, provides the device with the network device selection function on the network side, such as the MME, to provide the UE before the handover. The APN and the identifier of the gateway device, such as the PDN GW, so that the device with the network device selection function on the network side, such as the MME, selects the same gateway device as the PDN GW for the UE before the handover, and ensures that the UE switches from the old access network to the new one. After accessing the network, the session can continue to be used with the same IP address to avoid data transmission interruption.

A person skilled in the art can understand that all or part of the process of implementing the above embodiment method can be completed by a computer program to instruct related hardware, and the program can be stored in a computer readable storage medium. In execution, the flow of an embodiment of the methods as described above may be included. The storage medium may be a magnetic disk, an optical disk, or a read-only storage memory. RAM) and so on.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be carried in the protection of the present invention. Within the scope.

Claims

Rights request

1. A method for selecting network equipment during a handover process, characterized in that the method includes: receiving an instruction sent by a user equipment to switch the access network used by the session of the user equipment from the second access network to the first access network. Access network handover request message;

Obtain the first access point name used when the user equipment accesses the core network through the second access network, and obtain from the first network device when the user equipment accesses the core network through the second access network. The identifier of the first packet data network gateway used corresponding to the name of the first access point, the first network device is a network device that manages the user equipment on the network side, and the management is: subscription management, One or more of authentication management and location management;

Select the first access point name as the access point name used after the session of the user equipment is switched to the first access network, and select the packet indicated by the identification of the first packet data network gateway The data network gateway serves as the packet data network gateway used after the session of the user equipment is switched to the first access network.

2. The method according to claim 1, characterized in that: obtaining from the first network device the user equipment used when accessing the core network through the second access network and the first access point. The steps of identifying the first packet data network gateway corresponding to the name include:

Send a first request message to the first network device, where the first request message is used to request to obtain the identity of the first packet data network gateway used when the user equipment accesses the core network through the second access network. ;

Receive a first response message sent by the first network device, the first response message carries at least an identifier of the first packet data network gateway, and the identifier of the first packet data network gateway is the same as the first interface Corresponds to the entry point name.

3. The method of claim 2, wherein the first request message is a location update request or an authentication request or a gateway update request, and the first response message is a location update response. The network device is the home subscription server or authentication

4. The method according to claim 2 or 3, characterized in that, the method further includes: carrying first indication information in the first request message, so that the first network device performs the processing according to at least the After the first indication information determines that the access network used by the user equipment is changed from the second access network to the first access network, the step of sending the first response message is performed, and the first indication information Instructing that the access network used by the session before switching is the second access network or instructing that the access network used by the session is switched from the second access network to the first access network; and/ Or, the first network device changes the wireless access technology type of the user equipment from the second access network to the first access network, and determines that the access network used by the user equipment is changed from the second access network to the first access network. The step of sending the first response message is performed after the second access network becomes the first access network.

5. The method according to any one of claims 1 to 4, wherein the identity of the first packet data network gateway is specifically obtained by the first network device from a second network device, and the second network device It is an authentication server used when the user equipment accesses the core network through the second access network.

6. The method according to any one of claims 1 to 5, wherein the selecting the first access point name is used after the session of the user equipment is switched to the first access network. The name of the access point, select the packet data network gateway indicated by the identifier of the first packet data network gateway as the packet data network gateway used after the session of the user equipment is switched to the first access network. for:

According to the second instruction information, select the first access point name as the access point name used after the session of the user equipment is switched to the first access network, select the first group number The packet data network gateway indicated by the identity of the network gateway is used as the packet data network gateway used after the session of the user equipment is switched to the first access network, and the second indication information indicates the session before switching. The access network used is the second access network or the access network used for the session is instructed to be switched from the second access network to the first access network, the switching request message and/or The first response message carries the second indication information.

7. The method according to any one of claims 1 to 6, wherein the obtaining the first access point name used when the user equipment accesses the core network through the second access network is specifically: Obtain the first access point name from the handover request message, which carries the first access point name used when the user equipment accesses the core network through the second access network; or ,

Obtain the first access point name used by the user equipment when accessing the core network through the second access network from the first network device.

8. The method according to any one of claims 2 to 7, wherein the handover request message carries the first access point name, so that the first request message carries the first access point name. access point name, thereby causing the first network device to obtain the identity of the first packet data network gateway corresponding to the first access point name according to the first request message.

9. The method according to any one of claims 1 to 8, characterized in that, upon receiving the instruction sent by the user equipment, the access network used for the session is switched from the second access network to the first access network. After the step of sending the handover request message and before the step of obtaining from the first network device the identity of the first packet data network gateway corresponding to the first access point name, the method further includes:

According to the second access point name subscribed by the user equipment in the first access network and the identification of the second packet data network gateway corresponding to the second access point name in the first access network Select a second packet data network gateway, and send an establishment session message to the second packet data network gateway. request message;

After receiving a message sent by the second packet data network gateway indicating a failure to establish a session or a failure to switch, perform the step of obtaining the first packet data corresponding to the name of the first access point from the first network device. Steps for identifying network gateways.

10. The method according to any one of claims 1 to 9, characterized in that the first response message is specifically sent by the first network device under the following circumstances:

Determine the first access point name used when the user equipment accesses the core network through the second access network and the second access point name used when the user equipment accesses the core network through the first access network. The access point names are different; or,

Determine the first access point name used when the user equipment accesses the core network through the second access network and the second access point used when the user equipment accesses the core network through the first access network. The point names are the same, but the identifier of the first packet data network gateway is different from the identifier of the second packet data network gateway used when the user equipment accesses the core network through the first access network. The identifier of the data network gateway corresponds to the name of the second access point.

11. A method for selecting network equipment during handover, characterized in that the method includes:

Receive a first request message sent by a third network device, where the first request message is for the third network device to switch the access network used for the session from the second access network to the first after receiving an instruction sent by the user equipment. The first request message is sent after a handover request message of the access network, and the first request message is used to request to obtain the identity of the first packet data network gateway used when the user equipment accesses the core network through the second access network, so The third network device is a network device that selects a packet data network gateway;

Send a first response message to the third network device, where the first response message at least carries an identifier of the first packet data network gateway, so that the third network device selects the first connection. The access point name is used as the access point name used after the session of the user equipment is switched to the first access network, and the packet data network gateway indicated by the identifier of the first packet data network gateway is selected as the access point name. The packet data network gateway used after the session of the user equipment is switched to the first access network, wherein the name of the first access point is the access core of the user equipment through the second access network. The name of the access point used in the network, the first access point name is obtained by the third network device from the handover request message or the first response message, the identity of the first packet data network gateway Corresponds to the name of the first access point.

12. The method of claim 11, wherein the first request message is a location update request or an authentication request or a gateway update request, and the first response message is a location update response or an authentication response or a gateway Update response, the third network device is a network device that selects a packet data network gateway.

13. The method according to claim 11 or 12, characterized in that, before the step of sending the first response message to the third network device, it further includes: determining that the access network used by the user equipment is provided by the user equipment. The second access network becomes the first access network, specifically:

It is determined at least according to the first indication information that the access network used by the user equipment is changed from the second access network to the first access network, wherein the first indication information indicates the session used by the session before switching. The access network is the second access network or the access network used by the session is instructed to be switched from the second access network to the first access network, and the first request message carries the third access network. an instruction message; or,

By determining that the wireless access technology type of the user equipment is changed from the second access network to the first access network, it is determined that the access network used by the user equipment is changed from the second access network to The first access network.

14. The method according to any one of claims 11 to 13, characterized in that, the first response The identity of the first packet data network gateway carried in the message is specifically obtained from a second network device, where the second network device is used when the user equipment accesses the core network through the second access network. Authentication server.

15. The method according to any one of claims 11 to 14, wherein the first response message carrying at least the identification of the first packet data network gateway includes: the first response message carrying the The name of the first access point and the identification of the first packet data network gateway.

16. The method according to any one of claims 11 to 15, wherein the method further includes: carrying the first access point name in the handover request message, so that the first request message carries the first access point name, and according to the first access point name carried in the first request message, the first response message at least carries the identity of the first packet data network gateway , the identifier of the first packet data network gateway corresponds to the name of the first access point.

17. The method according to any one of claims 11 to 16, wherein before the step of sending the first response message to the third network device, the method further includes:

18. A device for selecting network equipment during handover, characterized in that the device includes:

A handover request message receiving unit, configured to receive a handover request message sent by the user equipment instructing to switch the access network used for the session of the user equipment from the second access network to the first access network; the first acquisition unit, Obtaining the first access point name used when the user equipment accesses the core network through the second access network;

A second acquisition unit configured to acquire, from the first network device, the name of the first packet data network gateway corresponding to the first access point name used when the user equipment accesses the core network through the second access network. Identification, the first network device is a network device that manages the user equipment on the network side, and the management is: one or more of subscription management, authentication management, and location management; a selection unit, used to select The first access point name obtained by the obtaining unit is used as the access point name used after the session of the user equipment is switched to the first access network, and the first packet data network obtained by the obtaining unit is selected. The packet data network gateway indicated by the identifier of the gateway is used as the packet data network gateway used after the session of the user equipment is switched to the first access network.

19. The device according to claim 18, characterized in that the second acquisition unit includes:

A first request message sending subunit, configured to send a first request message to the first network device, where the first request message is used to request to obtain when the user equipment accesses the core network through the second access network. an identification of the first packet data network gateway used;

The first response message receiving subunit is configured to receive the first response message sent by the first network device after the first request message sending subunit sends the first request message, and the first response message at least carries The identifier of the first packet data network gateway corresponds to the name of the first access point.

20. The device according to claim 19, wherein the first request message is a location update request or an authentication request or a gateway update request, and the first response message is a location update response or an authentication response or a gateway Update response, the first network device is a home subscription server or authentication server.

21. The apparatus according to claim 19 or 20, wherein the first request message carries first indication information, so that the first network device determines the user based on at least the first indication information. The step of sending a first response message is performed after the access network used by the device is changed from the second access network to the first access network, and the first indication information indicates the access network used by the session before switching. The access network is the second access network or the access network used for the session is instructed to be switched from the second access network to the first access network.

22. The device according to any one of claims 18 to 21, wherein the identification of the first packet data network gateway obtained by the second obtaining unit is specifically obtained by the first network device from the second network device, The second network device is an authentication server used when the user equipment accesses the core network through the second access network.

23. The device according to any one of claims 18 to 22, characterized in that the selection unit is specifically used to,

According to the second instruction information, select the first access point name as the access point name used after the session of the user equipment is switched to the first access network, select the first packet data network gateway The packet data network gateway indicated by the identifier is used as the packet data network gateway used after the session of the user equipment is switched to the first access network, wherein the second indication information indicates that the session is used before switching The access network is the second access network or the access network used for the session is instructed to be switched from the second access network to the first access network, the handover request message and/or the The first response message carries the second indication information.

24. The device according to any one of claims 18 to 23, wherein the first obtaining unit is specifically configured to obtain the first access point name from the switching request message, and the switching request message Carrying the first access point name used when the user equipment accesses the core network through the second access network; or,

Specifically, it is used to obtain the first access point name used by the user equipment when accessing the core network through the second access network from the first network device.

25. The device according to any one of claims 19 to 24, wherein the handover request message carries the first access point name, so that the first request message carries the first access point name. access point name, thereby causing the first network device to obtain the identity of the first packet data network gateway corresponding to the first access point name according to the first request message.

26. The device according to any one of claims 18 to 25, characterized in that the device further includes:

A session establishment request message sending unit configured to, after the switching request message receiving unit receives the switching request message, and before the second obtaining unit obtains the identity of the first packet data network gateway, according to the user The second access point name signed by the device in the first access network and the identifier of the second packet data network gateway corresponding to the second access point name in the first access network select the second group. The data network gateway sends a session establishment request message to the second packet data network gateway;

The execution unit is configured to, after receiving a message indicating a session establishment failure or a handover failure sent by the second packet data network gateway, notify the second acquisition unit to acquire the user equipment through the second interface from the first network device. The identifier of the first packet data network gateway corresponding to the name of the first access point used when accessing the core network.

27. A device for selecting network equipment during handover, characterized in that the device includes:

The first request message receiving unit is configured to receive the first request message sent by the third network device. The first request message is the access network used by the session when the third network device receives an instruction sent by the user device. The handover request message is sent after the second access network is switched to the first access network. The first request message is used to request to obtain the third user equipment used when accessing the core network through the second access network. An identification of a packet data network gateway, the third network device is the network device that selects the packet data network gateway;

A first response message sending unit, configured to send a first response message to the third network device, where the first response message at least carries an identifier of the first packet data network gateway, so that the third network device Selecting a first access point name as the access point name used after the session of the user equipment is switched to the first access network, and selecting the packet data indicated by the identification of the first packet data network gateway The network gateway serves as the packet data network gateway used after the session of the user equipment is switched to the first access network, wherein the name of the first access point is the user equipment through the second access network. The access point name used when the network accesses the core network, the first access point name is obtained by the third network device from the handover request message or the first response message, the first packet data The identifier of the network gateway corresponds to the name of the first access point.

28. The device according to claim 27, wherein the first request message is a location update request or an authentication request or a gateway update request, and the first response message is a location update response or an authentication response or a gateway Update response, the third network device is a network device that selects a packet data network gateway.

29. The device according to claim 27 or 28, characterized in that, the device further includes: a determining unit, configured to send the first response message in the first response message sending unit Before, it is determined that the access network used by the user equipment is changed from the second access network to the first access network.

30. The device of claim 29, wherein the determining unit is specifically configured to: before the first response message sending unit sends the first response message, determine the first response message based on at least the first indication information. The access network used by the user equipment is changed from the second access network to the first access network, wherein the first indication information indicates that the access network used by the session before switching is the second access network. To access the network or instruct the access network used for the session to be switched from the second access network to the first access network, the first request message carries the first indication information; or,

Before the first response message sending unit sends the first response message, by determining that the radio access technology type of the user equipment is changed from the second access network to the first access network, the The access network used by the user equipment is changed from the second access network to the first access network.

31. The apparatus according to any one of claims 27 to 30, wherein the identity of the first packet data network gateway carried in the first response message is specifically obtained from the second network device, wherein, The second network device is an authentication server used when the user equipment accesses the core network through the second access network.

32. The device according to any one of claims 27 to 31, wherein the first response message carrying at least the identification of the first packet data network gateway includes: the first response message carrying the The name of the first access point and the identification of the first packet data network gateway.

33. The device according to any one of claims 27 to 32, wherein the handover request message carries the first access point name, so that the first request message carries the first access point name. Access point name, according to the first access point name carried in the first request message, where The first response message carries at least an identifier of the first packet data network gateway, and the identifier of the first packet data network gateway corresponds to the name of the first access point.

34. The device according to any one of claims 27 to 33, characterized in that the device further includes a determining unit, specifically used for:

Before the first response message sending unit sends the first response message, determine the first access point name used by the user equipment when accessing the core network through the second access network and the user The name of the second access point used when the device accesses the core network through the first access network is different; or,

Before the first response message sending unit sends the first response message, it is determined that the first access point name used when the user equipment accesses the core network through the second access network is the same as the first access point name used by the user equipment through the second access network. The second access point used by the first access network to access the core network has the same name, but the identity of the first packet data network gateway is the same as the user equipment's access to the core network through the first access network. The identifier of the second packet data network gateway used is different, and the identifier of the second packet data network gateway corresponds to the name of the second access point.