WO2018058699A1 - 一种切换方法及设备 - Google Patents

一种切换方法及设备 Download PDF

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Publication number
WO2018058699A1
WO2018058699A1 PCT/CN2016/101826 CN2016101826W WO2018058699A1 WO 2018058699 A1 WO2018058699 A1 WO 2018058699A1 CN 2016101826 W CN2016101826 W CN 2016101826W WO 2018058699 A1 WO2018058699 A1 WO 2018058699A1
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WIPO (PCT)
Prior art keywords
address
network device
message
terminal
core network
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PCT/CN2016/101826
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English (en)
French (fr)
Inventor
吴晓波
辛阳
李岩
靳维生
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华为技术有限公司
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Publication of WO2018058699A1 publication Critical patent/WO2018058699A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/14—Reselecting a network or an air interface
    • H04W36/144—Reselecting a network or an air interface over a different radio air interface technology
    • H04W36/1443—Reselecting a network or an air interface over a different radio air interface technology between licensed networks

Definitions

  • the present invention relates to the field of communications technologies, and in particular, to a handover method and device.
  • 4th Generation (4G) mobile communication networks such as Long Term Evolution (LTE) networks
  • 4G network has won the praise of users and operators because of its fast communication speed, wide network spectrum and flexible communication.
  • 5G mobile communication network for example, requiring continuous wide-area coverage of 100 megabytes.
  • Mbps User experience rate per second
  • Gbps gigabyte per second
  • ms air interface delay within 1 millisecond
  • end-to-end delay within 100ms, reliability Guarantee and so on.
  • Interoperability between 4G networks and 2nd Generation (2G) mobile communication networks or 3rd Generation (3G) mobile communication networks involves many complex processes, such as mapping of bearer/tunnel models, mapping of quality of service (QoS) parameters, mapping of security parameters, default bearers, and allowable There is no default bearer handover, and so on.
  • QoS quality of service
  • Embodiments of the present invention provide a handover method and device, in order to simplify an interoperation process between different standard networks.
  • a first aspect of the embodiments of the present invention provides a handover method, including: a first core network device receives a first handover request from a second core network device, where the first handover request carries a first Internet Protocol IP address, The first IP address is used to establish a first access point name APN, where the first core network device is applied to a first standard network, and the second core network device is applied to a second standard network, where the An IP address is an IP address assigned by the second standard network to the terminal; the first core network device is a process for the terminal to initiate the establishment of the first APN in the first standard network; The first core network device is configured to initiate the establishment of the first APN by the terminal in the first standard network, where: the first core network device sends a first creation to the first gateway based on the first IP address.
  • the first core network device receives a first create session response from the first gateway, and the first create session response carries a third address assigned by the first system network to the terminal, where a create session response is used to indicate that the terminal uses the third IP address;
  • the first core network device sends a second handover request to the access network device, where the access network device is applied to the first a first network device that receives the response message of the second handover request from the access network device;
  • the first core network device sends the first handover request to the second core network device
  • the response message, the response message of the first handover request carries the third IP address.
  • the first APN is initiated by the terminal according to the first IP address, and Sending a second handover request to the access network device, and receiving a response message of the second handover request sent by the access network device, after which the response message of the first handover request is sent to the second core network device.
  • the terminal can switch from the second network system to the first network standard.
  • the solution provided by the embodiment of the present invention does not require complicated mapping processes such as QoS mapping, Bearer ID mapping, and location identification, which simplifies the interoperation process between different standard networks, and is beneficial to the process of switching the terminal to a different standard network. Reduce the signaling interaction process of the network side device and improve the switching efficiency.
  • the first handover request further carries indication information, where the indication information is used to indicate that the first core network device is to perform after the establishing process of the first APN is completed.
  • the second core network device sends the first notification message, the method further includes: the first core network device sending the first notification message to the second core network device, where the first notification message is used to notify the
  • the second core network device the first core network device establishes the first APN for the terminal based on the first IP address, and the first notification message carries the first IP address and the Third IP address.
  • the method before the first core network device sends the second handover request to the access network device, the method further includes: the first core network device receiving the bearer creation from the first gateway a request message; the first core network device sends a bearer creation response message to the first gateway.
  • the method further includes: the first core network device Initiating a process of establishing a second APN in the first standard network for the terminal.
  • the first handover request further carries a second IP address, where the second IP address is an IP address allocated by the second standard network to the terminal, the first core network
  • the device is configured to initiate a second APN establishment process in the first standard network, where the first core network device sends a second create session request to the first gateway;
  • the first gateway receives a second create session response, the second create session response carries a fourth IP address assigned by the first system network to the terminal, and the second create session response is used to indicate that the terminal uses The fourth IP address.
  • the response message of the first handover request carries at least one of the following: an attach accept message, where the attach accept message carries the information of the first APN, the first IP address, the first a third IP address and first usage information, the first usage information is used to indicate that the terminal uses the third IP address in the first standard network to replace the first IP address; and the packet data network PDN connection is established.
  • the PDN connection establishment accept message carries the information of the second APN; the session management SM request message, where the SM request message carries bearer information of the terminal in the first standard network.
  • the method further includes: the first core network The device sends a location update request message to the home subscriber server for the terminal; the first core network device receives a location update confirmation message from the home subscriber server.
  • the method further includes: the first core The network device sends a second notification message to the second core network device, where the second notification message is used to notify the second core network device that the first core network device is based on the second IP address.
  • the second APN is established by the terminal, and the second notification message carries the second IP address and the fourth IP address.
  • the PDN connection establishment accept message further carries the second IP address, the fourth IP address, and second usage information, where the second usage information is used to indicate that the terminal is in the first
  • the standard network uses the fourth IP address instead of the second IP address.
  • the first handover request further carries at least one of: an international mobile subscriber identity IMSI of the terminal, a security context of the terminal, a mobility management context of the terminal, the terminal a session management class context and terminal network capability information of the terminal in the first system network.
  • the method further includes: the first core network device from the first The gateway receives a bearer creation request message; the first core network device receives a completion message of switching to the first standard network from the access network device; the first core network device sends a bearer setup request to the access network device The first core network device receives a bearer setup response message from the access network device; the first core network device sends a bearer setup response message to the first gateway.
  • the method further includes: the first core network device to the first The second core network device sends a handover complete notification message; the first core network device receives a handover complete confirmation message from the second core network device.
  • a second aspect of the embodiments of the present invention further provides a handover method, including: a second core network device receiving a handover request message from an access network device, where the second core network device and the access network device application
  • the second core network device sends the first cut to the first core network device Transmitting the request, the first handover request carries a first Internet Protocol IP address, and the first IP address is used in a process of establishing a first access point name APN of the terminal in the first standard network, where the first core
  • the network device is applied to the first standard network, the first IP address is an IP address allocated by the second standard network to the terminal; and the second core network device receives the location from the first core network device a response message of the first handover request, where the response message of the first handover request carries a third IP address, where the third IP address is the first standard network in the process of establishing the first APN.
  • the IP address assigned by the terminal; the second core network device sends a handover request response message to the access network device.
  • the second core network device of the second standard network receives the handover request message sent by the access network device of the second standard network, and the second core network device sends the first handover to the first core network device of the first standard network.
  • the first switching request carries the first Internet Protocol IP address, and the first IP address is used to establish the first APN of the terminal in the first standard network.
  • the second core network device receives the first And sending, by the core network device, a response message of the first handover request, and sending a handover request response message to the access network device.
  • the solution of the embodiment of the present invention does not require complex QoS mapping, Bearer ID mapping, location identification and other mapping processes, which simplifies the interoperation process between different standard networks, and is beneficial to reduce the terminal switching to different standard networks.
  • the signaling interaction process of the network side device improves the switching efficiency.
  • the first handover request further carries indication information, where the indication information is used to indicate that the first core network device sends the second core network to the second core network after completing the setup process of the first APN.
  • the device sends a first notification message
  • the method further includes: the second core network device receiving the first notification message from the first core network device, where the first notification message is used to notify the second core a network device: the first core network device establishes the first APN for the terminal based on the first IP address, where the first notification message carries the first IP address and the first standard network a third IP address assigned to the terminal during the establishment of the first APN.
  • the method further includes: sending, by the second core network device, to the second policy device a third notification message, the third notification message is used to notify the second policy device: the first core network device establishes the first APN for the terminal based on the first IP address, where The second policy device is applied to the second standard network, and the third notification message carries the third IP address.
  • the first handover request further carries a second IP address, where the second IP address is used for establishing a second APN of the terminal in the first standard network, where The second IP address is an IP address assigned by the second standard network to the terminal.
  • the response message of the first handover request carries at least one of the following: an attach accept message, where the attach accept message carries the information of the first APN, the first IP address, the first a third IP address and first usage information, the first usage information is used to indicate that the terminal uses the third IP address in the first standard network to replace the first IP address; and the packet data network PDN connection is established.
  • the PDN connection establishment accept message carries the information of the second APN; the session management SM request message, where the SM request message carries bearer information of the terminal in the first standard network.
  • the PDN connection establishment accept message further carries the second IP address, the fourth IP address, and second usage information, where the second usage information is used to indicate that the terminal is in the first
  • the standard network uses the fourth IP address instead of the second IP address.
  • the handover request response message carries at least one of the following: the attach accept message, the PDN connection setup accept message, or the SM request message.
  • the method further includes: the second core network device receiving the first core network device a second notification message, the second notification message is used to notify the second core network device: the first core network device establishes the second APN for the terminal based on the second IP address, where The second notification message carries the second IP address and the fourth IP address allocated to the terminal during the establishment of the second APN.
  • the method further includes: the second core network device sending the third message to the second policy device a notification message, the third notification message is used to notify the second policy device: the first core network device establishes the first APN for the terminal based on the first IP address, where the The second policy device is applied to the second standard network, and the third notification message carries the third Or the second core network device sends a fourth notification message to the second policy device, where the fourth notification message is used to notify the second policy device: the first core network device is based on the The second IP address is used to establish the second APN for the terminal, the second policy device is applied to the second standard network, and the fourth notification message carries the fourth IP address.
  • the method before the second core network device sends the first handover request to the first core network device, the method further includes: the second core network device receiving an attach request message from the terminal, where The attach request message carries terminal network capability information of the terminal in the first standard network.
  • the method before the sending, by the second core network device, the first handover request to the first core network device, the method further includes: the second core network device sending a query request message to the terminal; The second core network device receives a query request response message from the terminal, and the query request response message carries terminal network capability information of the terminal in the first standard network.
  • the first handover request further carries at least one of: an international mobile subscriber identity IMSI of the terminal, a security context of the terminal, a mobility management context of the terminal, the terminal The session management class context and the terminal network capability information of the terminal in the first standard network.
  • the method further includes: the second core network device to the second The policy device sends a seventh notification message, where the seventh notification message is used to notify the second policy device that the terminal switches from the second standard network to the first standard network.
  • the seventh notification message carries the first IP address, the third IP address, and third usage information, where the third usage information is used to indicate that the application function device is in the first
  • the third IP address is used in the standard network to replace the first IP address, wherein the application function device is applied to the first system network and the second system network.
  • the seventh notification message further carries a second IP address, a fourth IP address, and fourth usage information, where the fourth usage information is used to indicate that the application function device is in the first standard network.
  • the fourth IP address is replaced with the fourth IP address.
  • the second core network device receives from the first core network device After the response message of the first handover request, the method further includes: the second core network device sending a handover complete confirmation message to the first core network device; and the second core network device to the second policy device And sending a ninth notification message, where the ninth notification message is used to notify the second policy device that the terminal switches from the second standard network to the first standard network.
  • the ninth notification message carries the first IP address, the third IP address, and third usage information, where the third usage information is used to indicate that the application function device is in the first
  • the third IP address is used in the standard network to replace the first IP address, wherein the application function device is applied to the first system network and the second system network.
  • the ninth notification message further carries a second IP address, a fourth IP address, and fourth usage information, where the fourth usage information is used to indicate that the application function device is in the first standard network.
  • the fourth IP address is replaced with the fourth IP address.
  • a third aspect of the embodiments of the present invention further provides a handover method, including: a second access network device sends a handover request message to a second core network device, where the handover request message is used to request to connect the terminal from the second standard network. Switching to the first standard network, wherein the second access network device and the second core network device are applied to the second standard network; the second access network device is from the second core network device Receiving a handover request response message, where the handover request response message carries at least one of: an attach accept message, a packet data network PDN connection setup accept message, or a session management SM request message, where the attach accept message carries the first core network device Information about a first access point name APN established by the terminal in the first standard network, a first Internet Protocol IP address allocated by the second standard network to the terminal, and the first standard network in the a third IP address and first usage information allocated to the terminal during the establishment of the first APN, where the first usage information is used to indicate that the terminal is in the The third IP address is used
  • the SM request message carries bearer information of the terminal in the first standard network; the second access network device sends a handover command message to the terminal, where the handover command message carries at least one of the following: The attach accept message, the PDN connection setup accept message, or the SM request message.
  • the second access network device of the second standard network is to the second core of the second standard network.
  • the network device sends a handover request message, where the handover request message is used to request to switch the terminal from the second standard network to the first standard network, and then the second access network device receives the handover request response message from the second core network device, and the second connection
  • the network access device sends a handover command message to the terminal, instructing the terminal to replace the first IP address with the third IP address in the first standard network.
  • the solution of the embodiment of the present invention does not require complex QoS mapping, Bearer ID mapping, location identification and other mapping processes, which simplifies the interoperation process between different standard networks, and is beneficial to reduce the terminal switching to different standard networks.
  • the signaling interaction process of the network side device improves the switching efficiency.
  • the PDN connection establishment accept message further carries a second IP address allocated by the second standard network to the terminal, and the first standard network in the process of establishing the second APN a fourth IP address and second usage information allocated to the terminal, the second usage information being used to indicate that the terminal replaces the second IP address by using the fourth IP address in a first-standard network.
  • a fourth aspect of the embodiments of the present invention further provides a handover method, including: receiving, by a terminal, a handover command message from a second access network device, where the handover command message carries at least one of the following: an attach accept message, a packet data network PDN a connection establishment accept message or a session management SM request message, where the attach accept message carries information that the first core network device is the first access point name APN established by the terminal in the first standard network, the first a first Internet Protocol IP address assigned by the two-standard network to the terminal, and a third IP address and first usage information allocated by the first-standard network to the terminal during the establishment of the first APN, The first usage information is used to indicate that the terminal replaces the first IP address by using the third IP address in the first standard network, where the PDN connection establishment accept message carries the first core network device as a The information about the second APN established by the terminal in the first-standard network, where the SM request message carries bearer information of the terminal in the first-standard network; Applying
  • the terminal receives the handover command message from the second access network device of the second-standard network, where the handover command message carries at least one of the following: an attach accept message, a packet data network PDN connection. Establishing an accept message or a session management SM request message. Second, the terminal accesses the first standard network according to at least one of an attach accept message, a PDN connection establishment accept message, or an SM request message, and finally connects to the first interface in the first standard network. The network access device sends a handover complete message, thereby implementing handover from the second-standard network to the first-standard network.
  • the solution of the embodiment of the present invention does not require complex QoS mapping, Bearer ID mapping, location identification and other mapping processes, which simplifies the interoperation process between different standard networks, and is beneficial to reduce the terminal switching to different standard networks.
  • the signaling interaction process of the network side device improves the switching efficiency.
  • the PDN connection establishment accept message further carries a second IP address allocated by the second standard network to the terminal, and the first standard network is established in the process of establishing the second APN.
  • the method further includes: the terminal does not use a fifth IP address, and the fifth IP address is the second standard network.
  • the terminal receives an IP address assigned to the terminal before the handover command message from the first access network device.
  • the method before the terminal receives the handover command message from the second access network device, the method further includes: the terminal sending an attach request message to the second core network device, where the attach request message is used The request is attached to the first-standard network, wherein the attach request message carries terminal network capability information of the terminal in the first-standard network, and the second core network device is applied to the second-standard network.
  • the method before the terminal receives the handover command message from the second access network device, the method further includes: the terminal receiving a query request message from the second core network device, where the second core The network device is applied to the second system network; the terminal sends a query request response message to the second core network device, where the query request response message carries terminal network capability information of the terminal in the first standard network. .
  • the method further includes:
  • the terminal establishes a second bearer for the terminal in the first standard network.
  • the method further includes:
  • the terminal Transmitting, by the terminal, an eleventh notification message to the application function device, where the eleventh notification message is used to notify the application function device: the terminal switches from the second standard network to the first standard network, where The application function device is applied to the first system network and the second system network.
  • the eleventh notification message carries the first IP address, the third IP address, and third usage information, where the third usage information is used to indicate that the application function device is in the The first IP address is replaced with the third IP address in a one-standard network, wherein the application function device is applied to the first system network and the second system network.
  • the eleven notification message further carries the second IP address, the fourth IP address, and fourth usage information, where the fourth usage information is used to indicate that the application function device is in the The fourth IP address is used in place of the second IP address in the first-standard network.
  • a fifth aspect of the embodiments of the present invention further provides a bearer establishment method, including: the application function device sends a service establishment request message to the second policy device for the terminal, where the service establishment request message carries the service request information, so that The second policy device establishes a first bearer for the service of the terminal in the second-standard network, where the application function device is applied to the first-standard network and the second-standard network, and the second policy device is applied to The second system network, the application function device receives a fifth notification message from the second policy device, where the fifth notification message is used to notify the application function device: the first core network device is based on the first The Internet Protocol IP address is that the terminal establishes a first access point name APN in the first standard network, and the fifth notification message carries a third IP that is allocated to the terminal in the process of establishing the first APN.
  • An address, and/or the application function device receives a sixth notification message from the second policy device, the sixth notification message being used to notify the application function
  • the first core network device establishes a second APN in the first standard network for the terminal based on the second IP address, and the sixth notification message is carried in the process of establishing the second APN.
  • the fourth IP address assigned by the terminal, the first IP address and the second IP address are IP addresses allocated by the second standard network to the terminal; the application function device is a location of the terminal
  • the service initiates a process of establishing a second bearer in the first-standard network.
  • the application function device is the service of the terminal in the Before the first mode network initiates the process of creating the second bearer, the method further includes: sending, by the application function device, an update user plane request message to the access forwarding gateway, to request the access forwarding gateway to be the first Updating the IP address to the third IP address, or for requesting the access forwarding gateway to update the second IP address to the fourth IP address; the application function device from the access forwarding gateway Receive an update user plane request response message.
  • the application function device is before the terminal creates a second bearer creation process in the first standard network, the method further includes: the application function device uses the third IP address Or the fourth IP address performs signaling plane communication with the terminal.
  • the application function device is a process for the terminal to initiate a second bearer in the first-standard network, including: the application function device according to the first IP address or the second The IP address is used to search for the service request information.
  • the application function device initiates the process of establishing the second bearer in the first standard network according to the service requirement information.
  • the method further includes: the application function device sending an authentication authorization request message to the first policy device, where the first policy device is applied to the first system network; The device receives an authentication authorization response message from the first policy device.
  • the method before the application function device sends the authentication authorization request message to the first policy device, the method further includes: the application function device searching according to the first IP address or the second IP address Address to the first policy device.
  • a sixth aspect of the embodiments of the present invention further provides a bearer establishment method, including: a second policy device receiving a service establishment request message from an application function device, where the service establishment request message carries service requirement information, where the second The policy device is applied to the second system network, where the application function device is applied to the first system network and the second system network; and the second policy device is terminated in the second system network according to the service requirement information.
  • the service establishes the first bearer.
  • the method further includes: the second policy device receiving a third notification message from the second core network device, where the third notification message is used to notify the second policy device: the first core
  • the network device establishes, by using the first Internet Protocol IP address, the first access point name APN in the first standard network, and the third notification message is carried in the process of establishing the first APN.
  • the heartbeat device receives a fourth notification message, where the fourth notification message is used to notify the second policy device: the first core network device establishes the terminal in the second standard network based on the second IP address a second APN, where the fourth notification message carries a fourth IP address allocated to the terminal in the process of establishing the second APN, where the first core network device is applied to the first standard network.
  • the second core network device is applied to the second standard network, and the first IP address and the second IP address are IP addresses allocated by the second standard network to the terminal; the second policy The device establishes a second bearer for the service of the terminal in the first standard network.
  • the method further includes: sending, by the second policy device, the application function device a fifth notification message, the fifth notification message is used to notify the application function device that the first core network device establishes the first terminal in the first standard network based on the first IP address An APN, the fifth notification message carries the third IP address, and/or the second policy device sends a sixth notification message to the application function device, where the sixth notification message is used to notify the first The core network device establishes the second APN in the first standard network, and the fifth notification message carries the fourth IP address, based on the second IP address.
  • the second policy device establishes a second bearer for the service of the terminal in the first standard network, including: the second policy device according to the first IP address or The second IP address is used to search for the service request information, and the second policy device establishes the second bearer in the first standard network for the terminal according to the service requirement information.
  • the method further includes: the second policy device transmitting a credit re-authorization request message to the second gateway; the second policy device receiving a credit re-authorization response message from the second gateway.
  • the method before the second policy device sends a credit re-authorization request message to the second gateway, the method further includes: the second policy device according to the first IP address or the second IP The address is addressed to the second gateway.
  • the method further includes: the second policy device receiving a seventh notification message or a ninth notification message from the second core network device, where the seventh notification message or the ninth notification message is used for notification
  • the second policy device the terminal switches from the second standard network to the first system The network, wherein the second core network device is applied to the second standard network.
  • the seventh notification message or the ninth notification message carries the first IP address, the third IP address, and third usage information, where the third usage information is used to indicate an application function device.
  • the first IP address is replaced with the third IP address in the first system network, wherein the application function device is applied to the first system network and the second system network.
  • the seventh notification message or the ninth notification message further carries the second IP address, the fourth IP address, and fourth usage information, where the fourth usage information is used to indicate the The application function device replaces the second IP address with the fourth IP address in the first system network.
  • the method further includes: the second policy device is configured according to the service requirement information The terminal establishes the second bearer in the first standard network.
  • the method further includes: sending, by the second policy device, the application function device And an eighth notification message, where the eighth notification message is used to notify the application function device that the terminal switches from the second standard network to the first standard network.
  • the eighth notification message carries the first IP address, the third IP address, and third usage information, where the third usage information is used to indicate that the application function device is in the first
  • the third IP address is used in the standard network to replace the first IP address, wherein the application function device is applied to the first system network and the second system network.
  • the eighth notification message further carries the second IP address, the fourth IP address, and fourth usage information, where the fourth usage information is used to indicate that the application function device is in the The fourth IP address is used in place of the second IP address in the first-standard network.
  • a seventh aspect of the embodiments of the present invention provides a first core network device, where the first core network device has a function of implementing behavior of a first core network device in the foregoing method design.
  • the functions may be implemented by hardware or by corresponding software implemented by hardware.
  • the hardware or software includes one or more modules corresponding to the functions described above.
  • the first core network device includes a processor that is configured The corresponding functions in the above methods are performed to support the first core network device. Further, the first core network device may further include a communication interface, where the communication interface is used to support communication between the first core network device and other network elements. Further, the first core network device may further include a memory for coupling with the processor, which stores necessary program instructions and data of the first core network device.
  • An eighth aspect of the embodiments of the present invention provides a second core network device, where the second core network device has a function of implementing behavior of a second core network device in the foregoing method design.
  • the functions may be implemented by hardware or by corresponding software implemented by hardware.
  • the hardware or software includes one or more modules corresponding to the functions described above.
  • the second core network device includes a processor configured to support the second core network device to perform corresponding functions in the above methods. Further, the second core network device may further include a communication interface, where the communication interface is used to support communication between the second core network device and other network elements. Further, the second core network device may further include a memory for coupling with the processor, which stores necessary program instructions and data of the second core network device.
  • a terminal having a function of implementing a behavior of a terminal in the design of the foregoing method.
  • the functions may be implemented by hardware or by corresponding software implemented by hardware.
  • the hardware or software includes one or more modules corresponding to the functions described above.
  • the terminal includes a processor configured to support the terminal in performing the corresponding functions of the above methods. Further, the terminal may further include a transceiver, where the transceiver is used to support communication between the terminal and the network element. Further, the terminal may further include a memory for coupling with the processor, which stores program instructions and data necessary for the terminal.
  • a tenth aspect of the embodiments of the present invention provides a first policy device, where the first policy device has a function of implementing behavior of a first policy device in the foregoing method design.
  • the functions may be implemented by hardware or by corresponding software implemented by hardware.
  • the hardware or software includes one or more modules corresponding to the functions described above.
  • an application function device which has a function of implementing an action of an application function device in the above method design.
  • the functions may be implemented by hardware or by corresponding software implemented by hardware.
  • the hardware or software includes one or more modules corresponding to the functions described above.
  • a second policy device is provided, where the second policy device has a function of implementing behavior of a second policy device in the foregoing method design.
  • the functions may be implemented by hardware or by corresponding software implemented by hardware.
  • the hardware or software includes one or more modules corresponding to the functions described above.
  • a thirteenth aspect of the embodiments of the present invention provides a method for establishing a bearer, including:
  • the application function device sends a service establishment request message to the second policy device, where the service establishment request message carries the service requirement information, so that the second policy device establishes a first bearer for the terminal in the second standard network, where the application The functional device is applied to the first standard network and the second standard network, and the second policy device is applied to the second standard network; the application function device receives an eighth notification message from the second policy device, where The eighth notification message is used to notify the application function device: the terminal switches from the second standard network to the first standard network; the application function device is initiated by the terminal in the first standard network The establishment process of the second bearer.
  • the eighth notification message carries the first IP address, the third IP address, and third usage information, where the third usage information is used to indicate that the application function device is in the first
  • the third IP address is used in the standard network to replace the first IP address, wherein the application function device is applied to the first system network and the second system network.
  • the eight notification message may further carry the second IP address, the fourth IP address, and fourth usage information, where the fourth usage information is used to indicate that the application function device is in the The fourth IP address is used in place of the second IP address in the first-standard network.
  • a fourteenth aspect of the embodiments of the present invention further provides a bearer establishing method, including:
  • the application function device sends a service establishment request message to the second policy device, where the service establishment request message carries the service requirement information, so that the second policy device establishes a first bearer for the terminal in the second standard network, where the application The functional device is applied to the first standard network and the second standard network, and the second policy device is applied to the second standard network; the application function device receives an eleventh notification message from the second policy device, The eleventh notification message is used to notify the application function device: the terminal switches from the second standard network to the first standard network; the application function device is the terminal in the first format The network initiates the establishment process of the second bearer.
  • the eleventh notification message carries the first IP address, the a third IP address and a third usage information, the third usage information being used to indicate that the application function device replaces the first IP address by using the third IP address in the first standard network, wherein the application function The device is applied to the first system network and the second system network.
  • the eleven notification message may further carry the second IP address, the fourth IP address, and fourth usage information, where the fourth usage information is used to indicate that the application function device is The fourth IP address is used in the first mode network to replace the second IP address.
  • a fifteenth aspect of the embodiments of the present invention further provides a handover method, including:
  • the second core network device receives the handover request message from the access network device, where the second core network device and the access network device are applied to the second standard network; and the second core network device is applied to the first core network
  • the device sends a first handover request, where the first handover request carries an address of the second core network device, and the second core network device receives a response message of the first handover request from the first core network device;
  • the core network device sends a seventh notification message to the second policy device, where the seventh notification message is used to notify the second policy device: the terminal switches from the second standard network to the first standard network
  • the second policy device is applied to the second standard network.
  • the seventh notification message carries the first IP address, the third IP address, and third usage information, where the third usage information is used to indicate that the application function device is in the first
  • the third IP address is used in the system to replace the first IP address, wherein the application function device is applied to the first system network and the second system network;
  • the seventh notification message further carries a second IP address, a fourth IP address, and fourth usage information, where the fourth usage information is used to indicate that the application function device is in the first format
  • the fourth IP address is used in the network instead of the second IP address.
  • a sixteenth aspect of the embodiments of the present invention provides a handover method, including:
  • the second core network device receives the handover request message from the access network device, where the second core network device and the access network device are applied to the second standard network; and the second core network device is applied to the first core network
  • the device sends a first handover request, where the first handover request carries an address of the second core network device, and the second core network device receives a response message of the first handover request from the first core network device; Receiving, by the core network device, a response message of the first handover request from the first core network device; the second core network device receiving a handover completion notification message from the first core network device; the second core
  • the heart network device sends a handover complete confirmation message to the first core network device; the second core network device sends a ninth notification message to the second policy device, where the ninth notification message is used to notify the second Policy device:
  • the terminal switches from the second standard network to the first standard network.
  • the ninth notification message carries the first IP address, the third IP address, and third usage information, where the third usage information is used to indicate that the application function device is in the first
  • the third IP address is used in the system to replace the first IP address, wherein the application function device is applied to the first system network and the second system network;
  • the ninth notification message further carries a second IP address, a fourth IP address, and fourth usage information, where the fourth usage information is used to indicate that the application function device is in the first format
  • the fourth IP address is used in the network instead of the second IP address.
  • a seventeenth aspect of the embodiments of the present invention provides a handover method, including:
  • the first core network device receives a first handover request from the second core network device, where the first handover request carries an address of the second core network device, the first core network device is applied to the first standard network, and the second The core network device is applied to the second system network; the first core network device sends a response message of the first handover request to the second core network device; the first core network device sends the response message to the second core network device Switching completion notification message; the first core network device receiving a handover complete confirmation message from the first core network device.
  • the method further includes: the first core network device is the terminal initiating the first in the first standard network The process of establishing an APN.
  • the second core network device is deployed in combination with the second gateway, and the address of the second core network device carried by the first handover request is used to find the first APN in the process of establishing the first APN. Addressing the second core network device.
  • the response message of the first handover request sent by the first core network device to the second core network device carries an attach accept message, where the attach accept message carries the first core network device.
  • the first core network device of the first standard network receives the second standard network.
  • the first APN is initiated by the terminal according to the first IP address and the address of the third core network device, and the second handover request is sent to the access network device, and Receiving a response message of the second handover request sent by the access network device, and then sending a response message of the first handover request to the second core network device.
  • the terminal can switch from the second network system to the first network standard.
  • the solution provided by the embodiment of the present invention does not require complicated mapping processes such as QoS mapping, Bearer ID mapping, and location identification, which simplifies the interoperation process between different standard networks, and is beneficial to the process of switching the terminal to a different standard network. Reduce the signaling interaction process of the network side device and improve the switching efficiency.
  • FIG. 1 is a schematic diagram of a possible network architecture according to an embodiment of the present invention
  • FIG. 2 is a schematic diagram of communication of a handover method according to an embodiment of the present invention.
  • FIG. 3 is a schematic diagram of communication of another handover method according to an embodiment of the present invention.
  • FIG. 3 is a schematic diagram of communication of another handover method according to an embodiment of the present invention.
  • 3b is a schematic diagram of communication of another handover method according to an embodiment of the present invention.
  • FIG. 3c is a schematic diagram of communication of another handover method according to an embodiment of the present invention.
  • FIG. 3 is a schematic diagram of communication of another handover method according to an embodiment of the present invention.
  • FIG. 4 is a schematic diagram of communication of a bearer establishment method according to an embodiment of the present invention.
  • 4a is a schematic diagram of communication of another bearer establishment method according to an embodiment of the present invention.
  • FIG. 5 is a schematic diagram of communication of another handover method according to an embodiment of the present invention.
  • FIG. 5 is a schematic diagram of communication of another handover method according to an embodiment of the present invention.
  • FIG. 5b is a schematic diagram of communication of another handover method according to an embodiment of the present invention.
  • FIG. 6 is a schematic diagram of communication of another bearer establishing method according to an embodiment of the present invention.
  • FIG. 6 is a schematic diagram of communication of another bearer establishing method according to an embodiment of the present invention.
  • FIG. 6b is a schematic diagram of communication of another bearer establishing method according to an embodiment of the present invention.
  • FIG. 7 is a schematic diagram of communication of an access point name establishment process according to an embodiment of the present invention.
  • FIG. 8 is a schematic diagram of communication of another method for establishing an access point name according to an embodiment of the present invention.
  • FIG. 9A is a schematic structural diagram of a first core network device according to an embodiment of the present disclosure.
  • FIG. 9B is a schematic structural diagram of another first core network device according to an embodiment of the present disclosure.
  • FIG. 10 is a schematic structural diagram of a second core network device according to an embodiment of the present disclosure.
  • FIG. 10B is a schematic structural diagram of another second core network device according to an embodiment of the present disclosure.
  • FIG. 11 is a schematic structural diagram of a second access network device according to an embodiment of the present disclosure.
  • FIG. 11B is a schematic structural diagram of another second access network device according to an embodiment of the present disclosure.
  • FIG. 12 is a schematic structural diagram of a terminal according to an embodiment of the present disclosure.
  • FIG. 12B is a schematic structural diagram of another terminal according to an embodiment of the present invention.
  • the network architecture and the service scenario described in the embodiments of the present invention are used to more clearly illustrate the technical solutions of the embodiments of the present invention, and do not constitute a limitation of the technical solutions provided by the embodiments of the present invention.
  • the technical solutions provided by the embodiments of the present invention are equally applicable to similar technical problems.
  • FIG. 1 shows a possible network architecture provided by an embodiment of the present invention.
  • the network architecture includes a 4G network, a 5G network, and an IP Multimedia Subsystem (IMS) network.
  • IMS IP Multimedia Subsystem
  • the terminal and the evolved base station (eNB, Evolved NodeB) in the 4G network may be connected by using a wireless link.
  • the network side device of the 4G network mainly includes a Mobility Management Entity (MME), a Serving Gateway (SGW), a Policy and Charging Rules Function (PCRF) entity, and a packet data network.
  • MME Mobility Management Entity
  • SGW Serving Gateway
  • PCRF Policy and Charging Rules Function
  • PDN Gateway PGW
  • HSS home subscriber server
  • HSS Home Subscriber Server
  • the network side device of the 5G network mainly includes a Control Plane Function (CP Function) entity and a User Plane Function (UP Function) entity.
  • CP Function Control Plane Function
  • UP Function User Plane Function
  • the IMS network includes a Proxy-Call Session Control Function (P-CSCF) entity, an Access Transfer Control Function (ATCF) entity, and an Access Transfer GateWay (ATGW) entity.
  • P-CSCF Proxy-Call Session Control Function
  • ATCF Access Transfer Control Function
  • ATGW Access Transfer GateWay
  • AF Application Function
  • an application layer entity that provides policy and charging control for a transport plane resource, and corresponds to a P-CSCF entity and an ATCF entity in the IMS network.
  • the terminal involved in the embodiments of the present invention may include various handheld devices, in-vehicle devices, wearable devices, computing devices, or other processing devices connected to the wireless modem, and various forms of user equipment (User Equipment). , UE), mobile station (MS), terminal device, and the like. For convenience of description, the devices mentioned above are collectively referred to as terminals.
  • the embodiment of the present invention provides a handover method, and a first core network device, a second core network device, a terminal, and a second access network device, and the like, based on the method.
  • the method includes: the second core network device receives a handover request message from the second access network device, where the second core network device and the second access network device are applied to the second standard network; the second core network device is first The core network device sends a first handover request, where the first handover request carries a first IP address, and the first IP address is used to establish a first APN of the terminal in the first standard network, where the first core network device is applied to the first In the standard network, the first IP address is the IP address assigned by the second standard network to the terminal; the first core network device is the terminal Initiating a process of establishing a first APN in a first-standard network, where the first core network device initiates a process of establishing a first APN in a first-standard network, where: the first core network device
  • the first core network device receives the first creation session response from the first gateway, and the first creation session response carries the third IP address assigned by the first system network to the terminal, and the first creation session response is used by the first core network device. Instructing the terminal to use the third IP address; the first core network device sends a second handover request to the first access network device, where the first access network device is applied to the first standard network; the first core network device is from the first The access network device receives the response message of the second handover request; the first core network device sends a response message of the first handover request to the second core network device, where the response message of the first handover request carries the third IP address; The network device sends a handover request response message to the second access network device; the second access network device sends a handover command message to the terminal; and the terminal accesses the first standard network; Terminal sends a handover complete message to the first access network device. It can be seen from the above that in the embodiment of the present invention, the interoperation process between the first standard network
  • the handover request response message may carry at least one of an attach accept message, a PDN connection setup accept message, or an SM request message; the handover command message may also carry the attach accept message, the PDN connection setup accept message, or the SM request. At least one of the messages; the terminal may access the first-standard network according to at least one of the attach accept message, the PDN connection setup accept message, or the SM request message.
  • the first standard network may be a 4G network, a 3G network, or a 2G network
  • the second standard network may be a 5G network
  • the first standard network may be a 5G network
  • the second standard network may be 4G network, 3G network or 2G network.
  • the solution of the embodiment of the present invention may be applied to other scenarios, which are not limited in the embodiment of the present invention.
  • FIG. 2 shows a handover method provided by an embodiment of the present invention.
  • the method includes: sections 201-212, as follows:
  • the second access network device sends a handover request message to the second core network device.
  • the second core network device receives the handover request message from the second access network device.
  • the handover request message is used to request to switch the terminal from the second-standard network to the first-standard network, where the second access network device and the second core network device are applied to the second-standard network.
  • the second core network device sends a first handover request to the first core network device.
  • the first core network device receives the first handover request from the second core network device.
  • the first handover request carries a first IP address, and the first IP address is used to establish a first access point name (APN) of the terminal in the first-standard network.
  • the first core network device is applied to the first-standard network, and the first IP address is an IP address assigned by the second-standard network to the terminal, for example, an IP address allocated by the second core network device to the terminal.
  • the first handover request further carries indication information, where the indication information is used to indicate that the first core network device first sends a first notification message to the second core network device after completing the setup process of the first APN.
  • the first handover request further carries a second IP address, where the second IP address is used for establishing a second APN of the terminal in the first-standard network, where the second IP address is allocated to the terminal by the second-standard network. IP address.
  • the second core network device may further receive an attach request message from the terminal, where the attach request message carrying terminal is in the first standard network. Terminal network capability information.
  • the second core network device may further send a query request message to the terminal; and receive a query request response message from the terminal, and query the request response message.
  • the terminal network capability information of the terminal in the first standard network may be further sent before the second core network device sends the first handover request to the first core network device.
  • the first handover request further carries at least one of: an international mobile subscriber identity IMSI of the terminal, a security context of the terminal, a mobility management context of the terminal, a session management class context of the terminal, and the terminal in the first-standard network.
  • Terminal network capability information is included in the first handover request.
  • the method of the embodiment of the present invention may further include: the second core network device sends the seventh notification to the second policy device.
  • the message, the seventh notification message is used to notify the second policy device that the terminal switches from the second standard network to the first standard network.
  • the seventh notification message carries the first IP address, the third IP address, and the third usage information, and the third usage information is used to indicate that the application function device uses the third IP address in the first-standard network.
  • the address replaces the first IP address, wherein the application function device is applied to the first system network and the second system network;
  • the seventh notification message further carries a second IP address, a fourth IP address, and fourth usage information, where the fourth usage information is used to indicate that the application function device uses the fourth IP address in the first standard network to replace the second IP address.
  • the method of the embodiment of the present invention may further include: the second core network device sends the handover completion to the first core network device. And confirming the message; the second core network device sends a ninth notification message to the second policy device, where the ninth notification message is used to notify the second policy device that the terminal switches from the second standard network to the first standard network.
  • the ninth notification message carries the first IP address, the third IP address, and the third usage information, and the third usage information is used to indicate that the application function device replaces the first IP with the third IP address in the first-standard network.
  • the ninth notification message may further carry the second IP address, the fourth IP address, and the fourth usage information, where the fourth usage information is used to indicate that the application function device replaces the fourth IP address in the first-standard network. Two IP addresses.
  • the first core network device initiates a process of establishing a first APN in the first standard network.
  • the process of the first core network device initiating the first APN may include: the first core network device sends a first create session request to the first gateway based on the first IP address; the first core network device receives from the first gateway The first create session response, the first create session response carries a third address assigned by the first-standard network to the terminal, and the first create session response is used to indicate that the terminal uses the third IP address.
  • the third IP address used by the terminal in the first-standard network corresponds to the first IP address used in the second-standard network, that is, the terminal switches from the second-standard network to the first After the standard network, the IP address used changes.
  • the first core network device may further send a location update request message to the home user server for the terminal; and from the home user.
  • the server receives a location update confirmation message.
  • the first core network device sends the terminal in the first standard network. After the first APN is established, the first core network device may further send a first notification message to the second core network device, where the first notification message is used to notify the second core network device that the first core network device is based on the first IP address.
  • the address establishes a first APN for the terminal, and the first notification message carries the first IP address and the third IP address.
  • the second core network device may further send a third notification message to the second policy device, where the third notification message is used to notify the second policy device.
  • the first core network device establishes a first APN for the terminal based on the first IP address, where the second policy device is applied to the second standard network, and the third notification message carries the third IP address.
  • the first core network device may further initiate the process of establishing the second APN in the first-standard network.
  • the process of establishing the second APN by the first core network device may include: the first core network device sends a second create session request to the first gateway; and the first core network device receives the second create session from the first gateway.
  • the second create session response carries a fourth IP address assigned by the first standard network to the terminal during the second APN establishment process, and the second create session response is used to indicate that the terminal uses the fourth IP address.
  • the first core network device may further send the first core network device to the second core network device.
  • a second notification message is used to notify the second core network device: the first core network device establishes a second APN for the terminal based on the second IP address, and the second notification message carries the second IP address and the Four IP addresses.
  • the second core network device may further send a third notification message to the second policy device, where the third notification message is used to notify the second policy device.
  • the first core network device establishes a first APN for the terminal based on the first IP address, where the second policy device is applied to the second standard network, and the third notification message carries the third IP address; or the second core network device
  • the second core network device may further send a fourth notification message to the second policy device, where the fourth notification message is used to notify the second policy device that the first core network device is based on the first
  • the second IP address establishes a second APN for the terminal, where The second policy device is applied to the second standard network, and the fourth notification message carries the fourth IP address.
  • the method of the embodiment of the present invention may further include: the first core network device receives the bearer creation request message from the first gateway.
  • the first core network device receives a completion message for switching to the first standard network from the access network device; the first core network device sends a bearer setup request message to the access network device; the first core network device receives the bearer from the access network device. Establishing a response message; the first core network device sends a bearer creation response message to the first gateway.
  • the method of the embodiment of the present invention may further include: the first core network device sends the handover to the second core network device.
  • the notification message is completed; the first core network device receives a handover complete confirmation message from the second core network device.
  • the first core network device sends a second handover request to the first access network device.
  • the first access network device is applied to the first standard network.
  • the first core network device may further receive a bearer creation request message from the first gateway; and send a bearer creation response to the first gateway. Message.
  • the first core network device receives a response message of the second handover request from the first access network device.
  • the first core network device sends a response message of the first handover request to the second core network device.
  • the second core network device receives the response message of the first handover request from the first core network device.
  • the response message of the first handover request carries a third IP address.
  • the response message of the first handover request may further carry a fourth IP address.
  • the response message of the first handover request may carry at least one of the following: an attach accept message, where the attach accept message carries the information of the first APN, the first IP address, the third IP address, and the first use information, The first usage information is used to indicate that the terminal uses the third IP address in place of the first IP address in the first standard network; the packet data network PDN connection establishment accept message, the PDN connection The establishment accept message carries the information of the second APN; or the session management SM request message, the SM request message carries the bearer information of the terminal in the first standard network.
  • the PDN connection establishment accept message may further carry a second IP address and a fourth IP address and second usage information, where the second usage information is used to indicate that the terminal uses the fourth IP address in the first standard network. Replace the second IP address.
  • the second core network device sends a handover request response message to the second access network device.
  • the second access network device receives the handover request response message from the second core network device.
  • the handover request response message carries at least one of the following: an attach accept message, the PDN connection setup accept message, or an SM request message.
  • the content of the attach accept message, the PDN connection setup accept message, or the SM request message may be referred to the detailed description in the foregoing section 206, and details are not described herein.
  • the second access network device sends a handover command message to the terminal.
  • the terminal receives the handover command message from the second access network device.
  • the handover command message carries at least one of the following: the attach accept message, the PDN connection setup accept message, or the SM request message.
  • the content of the attach accept message, the PDN connection setup accept message, or the SM request message may be referred to the detailed description in the foregoing section 206, and details are not described herein.
  • the PDN connection establishment accept message further carries a second IP address, a fourth IP address, and second usage information, where the second usage information is used to indicate that the terminal uses the fourth IP address instead of the first standard network.
  • Two IP addresses are used to indicate that the terminal uses the fourth IP address instead of the first standard network.
  • the terminal may not use the fifth IP address, where the fifth IP address is the second standard network before the terminal receives the handover command message from the first access network device.
  • the assigned IP address is the second standard network before the terminal receives the handover command message from the first access network device.
  • the terminal may further send an attach request message to the second core network device, where the attach request message is used to request to attach to the first standard network, where the attach request The message carries the terminal network capability information of the terminal in the first standard network.
  • the terminal before receiving the handover command message from the second access network device, the terminal may further receive the query request message from the second core network device; and send a query request to the second core network device.
  • the query request response message carries terminal network capability information of the terminal in the first standard network.
  • the terminal accesses the first standard network.
  • the terminal may access the first-standard network according to at least one of the attach accept message, the PDN connection establishment accept message, or the SM request message.
  • the terminal sends a handover complete message to the first access network device.
  • the first-standard network is a 4G network
  • the second-standard network is a 5G network
  • the first core network device is a mobility management entity MME of the 4G network
  • the second core network device is a control plane function of the 5G network.
  • the first access network device is an evolved base station eNB of the 4G network
  • the second access network device is a next-generation radio access network NG RAN entity of the 5G network
  • the first gateway is a serving gateway SGW of the 4G network
  • the second gateway is a PDN gateway PGW of the 4G network
  • the first policy device is a policy and charging rule function PCRF entity of the 4G network
  • the second policy device is a policy function Policy Function entity of the 5G network
  • the PCRF entity in the 4G network is The policy function of the 5G network is deployed independently.
  • the switching method disclosed in the embodiment of the present invention includes:
  • the terminal reports the neighbor cell signal measurement result to the NG RAN entity, and the NG RAN entity decides to switch the terminal from the 5G network to the 4G network.
  • the NG RAN entity sends a handover request message (for example, Handover Required) to the CP Function entity.
  • a handover request message for example, Handover Required
  • the CP Function entity After receiving the handover request message, the CP Function entity sends a first handover request (for example, Forward Relocation Request) to the MME.
  • a first handover request for example, Forward Relocation Request
  • a handover request carries: a first Internet Protocol IP address, and the first IP address is used for the establishment process of the first APN.
  • the terminal when the terminal further includes services such as VoLTE (LTE network voice service) and ViLTE (LTE network video service), in order to maintain the continuity of the service, a second APN needs to be established for the service.
  • a Dedicated APN such as an IMS APN
  • the first handover request may further carry: a second IP address of the terminal, where the second IP address is used for A process of establishing an access point name APN, wherein the first IP address and the second IP address are IP addresses allocated by the 5G network to the terminal.
  • the first handover request may further carry at least one of the following:
  • An International Mobile Subscriber Identification Number (IMSI) of the terminal, a security context of the terminal, a mobility management context of the terminal, a session management class context of the terminal, and the terminal is at the first Terminal network capability information for a standard network.
  • IMSI International Mobile Subscriber Identification Number
  • the terminal network capability information can be obtained by the following two methods:
  • the terminal carries the terminal network capability information in an attach request message (for example, an Attach Request) sent to the CP Function entity.
  • an attach request message for example, an Attach Request
  • the CP Function entity sends a query request message Query Request to the terminal, and the terminal carries the terminal network capability information in a query request response message sent to the CP Function entity.
  • the first handover request may further carry preset first indication information, where the preset first indication information is used to indicate to the MME that after completing the establishment process of the first APN, to the CP Function entity Send the first notification message.
  • the first handover request may further carry preset second indication information, where the preset second indication information is used to indicate to the MME that after completing the establishment process of the second APN, to the CP Function entity Send a second notification message.
  • the MME After receiving the first handover request, the MME initiates, according to the first IP address, a process for establishing, by the terminal, the first APN in the 4G network.
  • the process of establishing the first APN is also referred to as the attach process of the first APN.
  • the MME After completing the process of establishing the first APN, the MME sends the first notification message (for example, Notify1) to the CP Function entity.
  • the first notification message for example, Notify1
  • the first notification message carries the first IP address and a third IP address allocated to the terminal during the establishment of the first APN; the first notification message is used to notify the CP
  • the Function entity has the following information: the MME establishes the first APN for the terminal based on the first IP address.
  • the MME performs the step S304 only when it is detected that the first indication request carries the preset first indication information.
  • the CP Function entity After receiving the first notification message, the CP Function entity sends a third notification message (for example, Notify3) to the policy function Policy Function entity.
  • a third notification message for example, Notify3
  • the third notification message carries the first IP address and the third IP address, and the third notification message is used to notify the Policy Function entity that the MME is based on the first
  • the IP address establishes the first APN for the terminal.
  • the Policy Function entity After receiving the third notification message, the Policy Function entity sends a fifth notification message (for example, Notify5) to the application function AF device.
  • a fifth notification message for example, Notify5
  • the fifth notification message carries the first IP address and the third IP address, and the fifth notification message is used to notify the Policy Function entity that the MME is based on the first IP address.
  • the address establishes the first APN for the terminal.
  • the MME initiates, according to the second IP address, a process for establishing, by the terminal, the second APN in the 4G network.
  • the MME After completing the process of establishing the second APN, the MME sends the second notification message (for example, Notify2) to the CP Function entity.
  • the second notification message for example, Notify2
  • the second notification message carries the second IP address and a fourth IP address allocated to the terminal during the establishment of the second APN; the second notification message is used to notify the CP
  • the Function entity has the following information: the MME establishes the second APN for the terminal based on the second IP address.
  • the MME performs the step S308 only after detecting that the first handover request carries the preset second indication information.
  • the CP Function entity receives the second notification message, and sends a fourth notification message (for example, Notify4) to the policy function Policy Function entity.
  • a fourth notification message for example, Notify4
  • the fourth notification message carries the fourth IP address, and the fourth notification message is used to notify the Policy Function entity that the MME establishes the terminal for the terminal based on the second IP address.
  • the second APN The third APN.
  • the Policy Function entity After receiving the fourth notification message, the Policy Function entity sets the AF to the AF.
  • the sixth notification message Notify6 is sent.
  • the sixth notification message carries the fourth IP address, and the sixth notification message is used to notify the AF device that the MME establishes a location for the terminal based on the second IP address. Said second APN.
  • the AF device After receiving the fifth notification message or the sixth notification message, the AF device uses the third IP address (corresponding to a fifth notification message) or the fourth IP address (corresponding to a sixth notification message)
  • the terminal performs signaling plane communication, and simultaneously sends an update user plane request message (for example, Update User Plane Request) to the access forwarding gateway ATGW.
  • an update user plane request message for example, Update User Plane Request
  • the update user plane request message is used to request the ATGW to update the first IP address of the user plane to the third IP address, or to request the ATGW to use the second side of the user plane.
  • the IP address is updated to the fourth IP address.
  • the AF device receives an update user plane request response message (for example, an Update User Plane Response) from the ATGW.
  • an update user plane request response message for example, an Update User Plane Response
  • the AF device After receiving the fifth notification message or the sixth notification message, the AF device initiates a process of establishing a second bearer.
  • the MME After detecting, by the MME, that the first APN establishment is complete, the second APN establishment is complete (if any), and the second bearer setup is complete (if any), the MME sends a second handover request to the eNB. For example: Handover Request).
  • the eNB After receiving the second handover request, the eNB sends a response message (eg, Handover Request Acknowledge) of the second handover request to the MME.
  • a response message eg, Handover Request Acknowledge
  • the MME after receiving the response message of the second handover request, the MME sends a response message (for example, Forward Relocation Response) of the first handover request to the CP Function entity, where the response message of the first handover request carries Said third IP address.
  • a response message for example, Forward Relocation Response
  • the response message of the first handover request carries at least one of the following:
  • An attach accept message carrying information of the first APN, the first IP address, the third IP address, and first usage information, where the first usage information is used to indicate that the terminal is Replacing the first IP address with the third IP address in the first standard network;
  • a packet data network PDN connection establishment accept message, the PDN connection establishment accepting message carrying Information with the second APN;
  • the session management SM request message carries the bearer information of the terminal in the first standard network.
  • the CP Function entity After receiving the response message of the first handover request, the CP Function entity sends a handover request response message (for example, Handover Required Response) to the NG RAN entity.
  • a handover request response message for example, Handover Required Response
  • the handover request response message carries at least one of the following:
  • An attach accept message carrying information of the first APN, the first IP address, the third IP address, and first usage information, where the first usage information is used to indicate that the terminal is Replacing the first IP address with the third IP address in the first standard network;
  • the session management SM request message carries the bearer information of the terminal in the first standard network.
  • the PDN connection establishment accept message further carries the second IP address, the fourth IP address, and second usage information, where the second usage information is used to indicate that the terminal is used in a first-standard network.
  • the fourth IP address replaces the second IP address.
  • the NG RAN entity After receiving the handover request response message, the NG RAN entity sends a handover command message (for example, a Handover Command) to the terminal.
  • a handover command message for example, a Handover Command
  • the handover command message carries at least one of the following: an attach accept message, a packet data network PDN connection setup accept message, or a session management SM request message.
  • the attach accept message carries the information of the first APN, the first IP address, the third IP address, and the first use information, where the first use information is used to indicate that the terminal uses the in the 4G network.
  • the third IP address is used to replace the first IP address
  • the PDN connection establishment accept message carries information that the MME is the second APN established by the terminal on the 4G network, where the SM request message carries the terminal Bearer information of the 4G network.
  • the PDN connection establishment accept message further carries the second IP address, the fourth IP address, and second usage information, where the second usage information is used to indicate that the terminal uses the 4G network.
  • the fourth IP address replaces the second IP address.
  • the terminal sends a handover complete message (for example, Handover Complete) to the eNB entity.
  • a handover complete message for example, Handover Complete
  • FIG. 4 is a possible implementation manner of the process of creating a second bearer by the AF device in step S313 described in FIG.
  • the process of establishing the second bearer of the first IP address is the same.
  • the following takes the process of establishing the second bearer of the first IP address as an example to describe the specific process of establishing the second bearer, which specifically includes the following steps.
  • the AF device sends a service establishment request message to the Policy Function entity, that is, a setup request of the first bearer, and the service establishment request message carries a service request, before the terminal initiates the process of establishing the second bearer. information;
  • the first bearer is a bearer established by the service of the terminal in the 5G network, and when the terminal switches from the 5G network to the 4G network, in order to maintain service continuity, the 4G network is
  • the second bearer is established in the service of the terminal, and the step 1a is mainly to ensure that the AF device transmits the service requirement information to the Policy Function entity during the first bearer establishment process to ensure the 4G network.
  • the Policy Function entity directly initiates the establishment process of the second bearer for the service of the terminal by using the service requirement information.
  • the AF device searches for the service requirement information by using the first IP address of the 5G network, and after the third IP address of the 4G network is addressed to the PCRF entity, sends an authentication authorization request to the PCRF entity. Request, AAR) message.
  • the authentication authorization request message carries the third IP address.
  • the PCRF entity After receiving the authentication authorization request message, the PCRF entity addresses the PGW by using the third IP address, and sends a Re-authentication Request (RAR) message to the PGW.
  • RAR Re-authentication Request
  • the PGW After receiving the re-authentication request message, the PGW sends a Re-authentication Answer (RAA) message to the PCRF entity.
  • RAA Re-authentication Answer
  • the PCRF entity After receiving the RAA, the PCRF entity sends an Authentication Authorization Answer (AAA) message to the AF device.
  • AAA Authentication Authorization Answer
  • the PGW sends a bearer creation request message (for example, a Create Bearer Request) to the MME by using the SGW.
  • a bearer creation request message for example, a Create Bearer Request
  • the SGW forwards the bearer creation request message to the MME.
  • the MME After receiving the bearer creation request message, the MME sends a bearer creation response message (for example, a Create Bearer Response) to the SGW.
  • a bearer creation response message for example, a Create Bearer Response
  • the SGW forwards the bearer creation response message to the PGW.
  • the first-standard network is a 4G network
  • the second-standard network is a 5G network
  • the first core network device is a mobility management entity MME of the 4G network
  • the second core network device is a control plane function of the 5G network.
  • the first access network device is an evolved base station eNB of the 4G network
  • the second access network device is a next-generation radio access network NG RAN entity of the 5G network
  • the first gateway is a serving gateway SGW of the 4G network
  • the second gateway is a PDN gateway PGW of the 4G network
  • the first policy device is a policy and charging rule function PCRF entity of the 4G network
  • the second policy device is a policy function Policy Function entity of the 5G network
  • the PCRF entity in the 4G network is When the policy function of the 5G network is deployed in a unified manner, the handover method disclosed in the embodiment of the present invention specifically includes the following steps.
  • the terminal reports the neighbor cell signal measurement result to the NG RAN, and the NG RAN decides to switch the terminal from the 5G network to the 4G network.
  • the NG RAN entity sends a handover request message (for example, Handover Required) to the CP Function entity.
  • a handover request message for example, Handover Required
  • the CP Function entity After receiving the handover request message, the CP Function entity sends a first handover request (for example, a Forward Relocation Request) to the MME.
  • a first handover request for example, a Forward Relocation Request
  • a handover request carries a first Internet Protocol IP address, and the first IP address is used for the establishment process of the first APN.
  • a second APN needs to be established for the service, which is usually a Dedicated APN, such as an IMS APN.
  • the first handover request may also carry: the terminal of the terminal a second IP address, where the second IP address is used to establish a second access point name APN, wherein the first IP address and the second IP address are IP addresses allocated by the 5G network to the terminal .
  • the first handover request may further carry at least one of the following:
  • the international mobile subscriber identity IMSI of the terminal The international mobile subscriber identity IMSI of the terminal, the security context of the UE, the mobility management context of the terminal, the session management class context of the terminal, and the terminal network capability information of the terminal in the 4G network.
  • the terminal network capability information can be obtained by the following two methods:
  • the terminal 1 carries the terminal network capability information in an attach request message sent to the CP Function entity.
  • the method 2 the CP Function entity sends a query request message Query Request to the terminal, and the terminal carries the terminal network capability information in a query request response message sent to the CP Function entity.
  • the first handover request may further carry preset first indication information, where the preset first indication information is used to indicate that the MME sends the CP to the CP after completing the establishment process of the first access point name APN.
  • the Function entity sends a first notification message.
  • the first handover request may further carry preset second indication information, where the preset second indication information is used to indicate that the MME sends the CP to the CP after completing the establishment process of the second access point name APN.
  • the Function entity sends a second notification message.
  • the MME After receiving the first handover request, the MME is configured to initiate, by the terminal, the first access point name APN in the 4G network according to the first IP address.
  • the establishing process of the first APN may be referred to as an attaching process of the first APN.
  • the MME After completing the process of establishing the first APN, the MME sends the first notification message (for example, Notify1) to the CP Function entity.
  • the first notification message for example, Notify1
  • the first notification message carries the first IP address and a third IP address allocated to the terminal during the establishment of the first APN; the first notification message is used to notify the CP
  • the Function entity has the following information: the MME establishes the first APN for the terminal based on the first IP address.
  • the MME carries the pre-received only when detecting the foregoing first handover request. In the case where the first indication information is set, this step S504 is performed.
  • the CP Function entity After receiving the first notification message, the CP Function entity sends a third notification message (for example, Notify3) to the Policy Function entity.
  • a third notification message for example, Notify3
  • the third notification message carries the first IP address and the third IP address, and the third notification message is used to notify the Policy Function entity that the MME is based on the first
  • the IP address establishes the first APN for the terminal.
  • the Policy Function entity After receiving the third notification message, the Policy Function entity sends a fifth notification message to the application function AF device.
  • the fifth notification message carries the first IP address and the third IP address, and the fifth notification message is used to notify the AF device that the MME is based on the first IP address.
  • the address establishes the first APN for the terminal.
  • the MME initiates a process of establishing a second APN in the 4G network according to the second IP address.
  • the MME After completing the establishment process of the second APN, the MME sends the second notification message (for example, Notify2) to the CP Function entity.
  • the second notification message for example, Notify2
  • the second notification message carries the second IP address and a fourth IP address allocated to the terminal during the establishment of the second APN; the second notification message is used to notify the CP
  • the Function entity has the following information: the MME establishes the second APN for the terminal based on the second IP address.
  • the MME performs the step S508 only after detecting that the first handover request carries the preset second indication information.
  • the CP Function entity receives the second notification message, and sends a fourth notification message (for example, Notify4) to the policy function Policy Function entity.
  • a fourth notification message for example, Notify4
  • the fourth notification message carries the second IP address and a fourth IP address allocated to the terminal during the establishment of the second APN; the fourth notification message is used to notify the policy.
  • the Function entity has the following information: the MME establishes the second APN for the terminal based on the second IP address.
  • the Policy Function entity After receiving the fourth notification message, the Policy Function entity sets the AF to the AF.
  • a sixth notification message (for example, Notify6) is sent.
  • the sixth notification message carries the second IP address and a fourth IP address allocated to the terminal during the establishment of the second APN; the sixth notification message is used to notify the AF
  • the device has the following information: the MME establishes the second APN for the terminal based on the second IP address.
  • the AF device After receiving the fifth notification message or the sixth notification message, the AF device uses the third IP address (corresponding to a fifth notification message) or the fourth IP address (corresponding to a sixth notification message)
  • the terminal performs signaling plane communication, and simultaneously sends an update user plane request message (for example, Update User Plane Request) to the access forwarding gateway ATGW.
  • an update user plane request message for example, Update User Plane Request
  • the update user plane request message is used to request the ATGW to update the first IP address of the user plane to the third IP address, or to request the ATGW to use the second side of the user plane.
  • the IP address is updated to the fourth IP address.
  • the AF device receives an update user plane request response message (for example, an Update User Plane Response) from the ATGW.
  • an update user plane request response message for example, an Update User Plane Response
  • the Policy Function entity After receiving the fifth notification message or the sixth notification message, the Policy Function entity initiates a process of establishing a second bearer.
  • the MME sends a second handover request to the eNB ( For example: Handover Request).
  • the eNB After receiving the second handover request, the eNB sends a response message (eg, Handover Request Acknowledge) of the second handover request to the MME.
  • a response message eg, Handover Request Acknowledge
  • the MME After receiving the response message of the second handover request, the MME sends a response message (for example, Forward Relocation Response) of the first handover request to the CP Function entity.
  • a response message for example, Forward Relocation Response
  • the response message of the first handover request carries at least one of the following: an attach accept message, where the attach accept message carries the information of the first APN, the first IP address, the third IP address, and First usage information, the first usage information is used to indicate that the terminal replaces the first IP address by using the third IP address in the first standard network; a packet data network PDN
  • the connection establishment accept message the PDN connection establishment accept message carries information of the second APN;
  • the session management SM request message the SM request message carries bearer information of the terminal in the first standard network.
  • the PDN connection establishment accept message carries the second IP address, the fourth IP address, and second usage information, where the second usage information is used to indicate that the terminal uses the 4G network.
  • the fourth IP address replaces the second IP address.
  • the CP Function entity After receiving the response message of the first handover request, the CP Function entity sends a handover request response message (for example, Handover Required Response) to the NG RAN entity.
  • a handover request response message for example, Handover Required Response
  • the handover request response message carries at least one of the following:
  • An attach accept message carrying information of the first APN, the first IP address, the third IP address, and first usage information, where the first usage information is used to indicate that the terminal is Replacing the first IP address with the third IP address in the first standard network;
  • the session management SM request message carries the bearer information of the terminal in the first standard network.
  • the PDN connection establishment accept message further carries the second IP address and the fourth IP address and second usage information, where the second usage information is used to indicate that the terminal uses the 4G network.
  • the fourth IP address replaces the second IP address.
  • the NG RAN entity After receiving the handover request response message, the NG RAN entity sends a handover command message (for example, a Handover Command) to the terminal.
  • a handover command message for example, a Handover Command
  • the handover command message carries at least one of the following: an attach accept message, a packet data network PDN connection setup accept message, or a session management SM request message; wherein the attach accept message carries the first core network device as the terminal Information of a first access point name APN established in the first-standard network, a first Internet Protocol IP address allocated by the second-standard network to the terminal, and the first-standard network in the first APN a third IP address and first usage information allocated to the terminal during the establishing process, the first usage information being used to indicate that the terminal uses the third IP address in the first standard network to replace the First IP address, the PDN connection is established
  • the receiving message carries the information that the first core network device is the second APN established by the terminal in the first standard network
  • the SM request message carries the bearer information of the terminal in the first standard network.
  • the PDN connection establishment accept message further carries the second IP address, the fourth IP address, and second usage information, where the second usage information is used to indicate that the terminal uses the 4G network.
  • the fourth IP address replaces the second IP address.
  • the terminal sends a handover complete message (for example, Handover Complete) to the eNB entity.
  • a handover complete message for example, Handover Complete
  • FIG. 6 is a possible implementation manner of a process for creating a second dedicated bearer in step S513 described in FIG.
  • the process of establishing the second bearer of an IP address is the same.
  • the following takes the process of establishing the second bearer of the first IP address as an example to describe the specific process of establishing the second bearer, and specifically includes the following steps.
  • the Policy Function entity receives a service establishment request message from the AF device, that is, a setup request of the first bearer, where the service establishment request message carries the service request information;
  • the first bearer is a bearer established by the service of the terminal in the 5G network, and when the terminal switches from the 5G network to the 4G network, in order to maintain the continuity of the service,
  • the step 1a is mainly to ensure that the policy function entity receives the service request information from the AF entity during the first bearer setup process, and ensures that the service request information is ensured.
  • the Policy Function entity may directly initiate the second bearer for the service of the terminal by using the service requirement information. The establishment process.
  • the Policy Function entity searches for service requirement information through a first IP address of the 5G network, and addresses the PGW through a third IP address of the 4G network, and sends a re-authentication request message to the PGW.
  • the PGW After receiving the re-authentication request message, the PGW sends a re-authentication response message to the PCRF entity.
  • the PGW sends a bearer creation request message to the SGW (for example: Create Bearer Request).
  • the SGW forwards the bearer creation request message to the MME.
  • the MME After receiving the bearer creation request message, the MME sends a bearer creation response message (for example, a Create Bearer Response) to the SGW.
  • a bearer creation response message for example, a Create Bearer Response
  • the SGW forwards the bearer creation response message to the PGW.
  • the first-standard network is a 4G network
  • the second-standard network is a 5G network
  • the first core network device is a mobility management entity MME of the 4G network
  • the second core network device is a control plane function of the 5G network.
  • the first access network device is an evolved base station eNB of the 4G network
  • the second access network device is a next-generation radio access network NG RAN entity of the 5G network
  • the first gateway is a serving gateway SGW of the 4G network
  • the second gateway is a PDN gateway PGW of the 4G network
  • the first policy device is a policy and charging rule function PCRF entity of the 4G network
  • the second policy device is a policy function Policy Function entity of the 5G network
  • the PCRF entity in the 4G network is The policy function of the 5G network is deployed independently.
  • the switching method disclosed in the embodiment of the present invention includes:
  • the terminal reports the neighbor cell signal measurement result to the NG RAN entity, and the NG RAN entity decides to switch the terminal from the 5G network to the 4G network.
  • the NG RAN entity sends a handover request message (for example, Handover Required) to the CP Function entity.
  • a handover request message for example, Handover Required
  • the CP Function entity After receiving the handover request message, the CP Function entity sends a first handover request (for example, Forward Relocation Request) to the MME.
  • a first handover request for example, Forward Relocation Request
  • a handover request carries: a first Internet Protocol IP address, and the first IP address is used for the establishment process of the first APN.
  • the terminal when the terminal further includes services such as VoLTE (LTE network voice service) and ViLTE (LTE network video service), in order to maintain the continuity of the service, a second APN needs to be established for the service.
  • a Dedicated APN such as an IMS APN
  • the first handover request may further carry: a second IP address of the terminal, where the second IP address is used to establish a second access point name APN. a process, wherein the first IP address and the second IP address It is an IP address assigned by the 5G network to the terminal.
  • the first handover request may further carry at least one of the following:
  • An International Mobile Subscriber Identification Number (IMSI) of the terminal, a security context of the terminal, a mobility management context of the terminal, a session management class context of the terminal, and the terminal is at the first Terminal network capability information for a standard network.
  • IMSI International Mobile Subscriber Identification Number
  • the terminal network capability information can be obtained by the following two methods:
  • the terminal carries the terminal network capability information in an attach request message (for example, an Attach Request) sent to the CP Function entity.
  • an attach request message for example, an Attach Request
  • the CP Function entity sends a query request message Query Request to the terminal, and the terminal carries the terminal network capability information in a query request response message sent to the CP Function entity.
  • the MME after receiving the first handover request, the MME initiates a process of establishing a first access point name APN in the 4G network.
  • the MME is a process for the terminal to initiate a second access point APN in the 4G network.
  • the MME sends a second handover request (for example, a Handover Request) to the eNB.
  • a second handover request for example, a Handover Request
  • the eNB After receiving the second handover request, the eNB sends a response message (eg, Handover Request Acknowledge) of the second handover request to the MME.
  • a response message eg, Handover Request Acknowledge
  • the MME after receiving the response message of the second handover request, the MME sends a response message (for example, Forward Relocation Response) of the first handover request to the CP Function entity, where the response message of the first handover request carries Said third IP address.
  • a response message for example, Forward Relocation Response
  • the response message of the first handover request carries at least one of the following:
  • An attach accept message carrying information of the first APN, the first IP address, the third IP address, and first usage information, where the first usage information is used to indicate that the terminal is Replacing the first IP address with the third IP address in the first standard network;
  • a packet data network PDN connection establishment accept message, the PDN connection establishment accepting message carrying Information with the second APN.
  • the CP Function entity after receiving the first handover request response, the CP Function entity sends a seventh notification message (for example, Notify7) to the Policy Function entity.
  • a seventh notification message for example, Notify7
  • the seventh notification message is used to notify the Policy Function entity that the terminal switches from the 5G network to the 4G network, and the seventh notification message carries the first IP address, the a third IP address and a third usage information, the third usage information being used to indicate that the application function device replaces the first IP address by using the third IP address in the first standard network, wherein the application function The device is applied to the first system network and the second system network.
  • the seven notification message may further carry the second IP address, the fourth IP address, and fourth usage information, where the fourth usage information is used to indicate that the application function device is in the first
  • the fourth IP address is used in place of the second IP address in the standard network.
  • the first handover request in the step S3a02 may not carry the The address of the CP Function is directly carried by the first IP address or the second IP address, where the address of the CP Function is used in the process of establishing the first APN in step S3a03, and the step S3a04 Addressing the CP Function entity in the process of establishing the second APN, in which case the CP Function entity sends the seventh notification message to the Policy Function entity after receiving the first handover request response. Notify7.
  • the Policy Function entity after receiving the seventh notification message, the Policy Function entity sends an eighth notification message (for example, Notify8) to the AF device.
  • an eighth notification message for example, Notify8
  • the eighth notification message is used to notify the AF device that the terminal switches from the 5G network to the 4G network, and the eighth notification message carries the first IP address, the first a third IP address and a third usage information, the third usage information being used to indicate that the application function device replaces the first IP address with the third IP address in the first standard network, wherein the application function device Applied to the first system network and the second system network.
  • the eight notification message may further carry the second IP address, the fourth IP address, and fourth usage information, where the fourth usage information is used to indicate that the application function device is in the first
  • the fourth IP address is used in place of the second IP address in the standard network.
  • the AF device after receiving the eighth notification message, performs signaling plane communication with the terminal by using the third IP address or the fourth IP address (if any), and simultaneously accesses the forwarding and forwarding gateway ATGW.
  • Send an update user plane request message (for example: Update User Plane Request).
  • the update user plane request message is used to request the ATGW to update the first IP address of the user plane to the third IP address, or to request the ATGW to use the second side of the user plane.
  • the IP address is updated to the fourth IP address.
  • the AF device receives an update user plane request response message (for example, an Update User Plane Response) from the ATGW.
  • an update user plane request response message for example, an Update User Plane Response
  • the first standard network is a 4G network
  • the second system is a 5G network
  • the first core network device is a 4G network mobility management entity MME
  • the second core network device is a 5G network control plane function.
  • the first access network device is an evolved base station eNB of the 4G network
  • the second access network device is a next-generation radio access network NG RAN entity of the 5G network
  • the first gateway is a serving gateway SGW of the 4G network
  • the second gateway is a PDN gateway PGW of the 4G network
  • the first policy device is a policy and charging rule function PCRF entity of the 4G network
  • the second policy device is a policy function Policy Function entity of the 5G network
  • the PCRF entity in the 4G network is The policy function of the 5G network is deployed independently.
  • the switching method disclosed in the embodiment of the present invention includes:
  • the terminal reports the neighbor cell signal measurement result to the NG RAN entity, and the NG RAN entity decides to switch the terminal from the 5G network to the 4G network.
  • the NG RAN entity sends a handover request message (for example, Handover Required) to the CP Function entity.
  • a handover request message for example, Handover Required
  • the CP Function entity after receiving the handover request message, the CP Function entity sends a first handover request (for example, Forward Relocation Request) to the MME.
  • a first handover request for example, Forward Relocation Request
  • a handover request carries: a first Internet Protocol IP address, and the first IP address is used for the establishment process of the first APN.
  • the terminal when the terminal further includes services such as VoLTE (LTE network voice service) and ViLTE (LTE network video service), in order to maintain the continuity of the service, a second APN needs to be established for the service.
  • a Dedicated APN such as an IMS APN
  • the first handover request may further carry: a second IP address of the terminal, where the second IP address is used to establish a second access point name APN.
  • the process, wherein the first IP address and the second IP address are IP addresses assigned by the 5G network to the terminal.
  • the first handover request may further carry at least one of the following:
  • An International Mobile Subscriber Identification Number (IMSI) of the terminal, a security context of the terminal, a mobility management context of the terminal, a session management class context of the terminal, and the terminal is at the first Terminal network capability information for a standard network.
  • IMSI International Mobile Subscriber Identification Number
  • the terminal network capability information can be obtained by the following two methods:
  • the terminal carries the terminal network capability information in an attach request message (for example, an Attach Request) sent to the CP Function entity.
  • an attach request message for example, an Attach Request
  • the CP Function entity sends a query request message Query Request to the terminal, and the terminal carries the terminal network capability information in a query request response message sent to the CP Function entity.
  • the MME after receiving the first handover request, the MME initiates a process of establishing a first access point name APN in the 4G network.
  • the MME is a process for the terminal to initiate a second access point APN in the 4G network.
  • the MME sends a second handover request (for example, a Handover Request) to the eNB.
  • a second handover request for example, a Handover Request
  • the eNB After receiving the second handover request, the eNB sends a response message (eg, Handover Request Acknowledge) of the second handover request to the MME.
  • a response message eg, Handover Request Acknowledge
  • the MME after receiving the response message of the second handover request, the MME sends a response message (for example, Forward Relocation Response) of the first handover request to the CP Function entity, where the response message of the first handover request carries Said third IP address.
  • a response message for example, Forward Relocation Response
  • the response message of the first handover request carries at least one of the following:
  • An attach accept message carrying information of the first APN, the first IP address, the third IP address, and first usage information, where the first usage information is used to indicate that the terminal is Replacing the first IP address with the third IP address in the first standard network;
  • the packet data network PDN connection establishment accept message, the PDN connection establishment accept message carrying information of the second APN.
  • the CP Function entity after receiving the response message of the first handover request, the CP Function entity sends a handover request response message (for example, Handover Required Response) to the NG RAN entity.
  • a handover request response message for example, Handover Required Response
  • the handover request response message carries at least one of the following:
  • An attach accept message carrying information of the first APN, the first IP address, the third IP address, and first usage information, where the first usage information is used to indicate that the terminal is Replacing the first IP address with the third IP address in the first standard network;
  • the packet data network PDN connection establishment accept message, the PDN connection establishment accept message carrying information of the second APN.
  • the PDN connection establishment accept message further carries the second IP address, the fourth IP address, and second usage information, where the second usage information is used to indicate that the terminal is used in a first-standard network.
  • the fourth IP address replaces the second IP address.
  • the NG RAN entity after receiving the handover request response message, the NG RAN entity sends a handover command message (for example, a Handover Command) to the terminal.
  • a handover command message for example, a Handover Command
  • the handover command message carries at least one of the following: an attach accept message, a packet data network PDN connection setup accept message.
  • the attach accept message carries the information of the first APN, the first IP address, the third IP address, and the first use information, where the first use information is used to indicate that the terminal uses the in the 4G network.
  • the third IP address is used to replace the first IP address, and the PDN connection establishment accept message carries information that the MME is the second APN established by the terminal on the 4G network.
  • the PDN connection establishment accept message further carries the second IP address, the fourth IP address, and second usage information, where the second usage information is used to indicate that the terminal is in a 4G network.
  • the fourth IP address is replaced with the fourth IP address.
  • S3b10 The terminal sends a handover complete message (for example, Handover Complete) to the eNB entity.
  • a handover complete message for example, Handover Complete
  • the eNB entity after receiving the handover complete message, the eNB entity sends a completion message (for example, Handover to E-UTRAN Complete) to the MME entity to switch to the 4G network;
  • a completion message for example, Handover to E-UTRAN Complete
  • the MME entity After receiving the completion message of the handover to the 4G network, the MME entity sends a handover completion notification message (for example, Forward Relocation Complete Notification) to the CP Function entity.
  • a handover completion notification message for example, Forward Relocation Complete Notification
  • the CP Function entity After receiving the handover completion notification message, the CP Function entity sends a handover complete acknowledgement message (for example, Forward Relocation Complete Acknowledge) to the MME entity.
  • a handover complete acknowledgement message for example, Forward Relocation Complete Acknowledge
  • S3b14 After sending the handover completion acknowledgement message, the CP Function entity sends a ninth notification message (for example, Notify9) to the Policy Function entity.
  • a ninth notification message for example, Notify9
  • the ninth notification message is used to notify the Policy Function entity that the terminal switches from the 5G network to the 4G network, and the ninth notification message carries the first IP address, the a third IP address and a third usage information, the third usage information being used to indicate that the application function device replaces the first IP address by using the third IP address in the first standard network, wherein the application function The device is applied to the first system network and the second system network.
  • the nine notification message may further carry the second IP address, the fourth IP address, and fourth usage information, where the fourth usage information is used to indicate that the application function device is in the first
  • the fourth IP address is used in place of the second IP address in the standard network.
  • the first handover request in the step S3b02 may not carry the a first IP address or the second IP address, but directly carrying the address of the CP Function, where the address of the CP Function is used in the process of establishing the first APN in step S3b03, in step S3b04 Addressing the CP Function entity in the process of establishing the second APN, in which case the CP Function entity sends the ninth notification message Notify9 to the Policy Function entity after sending the handover completion acknowledgement message. .
  • the Policy Function entity After receiving the ninth notification message, the Policy Function entity sends a tenth notification message (for example, Notify10) to the AF device.
  • a tenth notification message for example, Notify10
  • the tenth notification message is used to notify the AF device that the terminal switches from the 5G network to the 4G network, and the tenth notification message carries the first IP address, the first a third IP address and a third usage information, the third usage information being used to indicate that the application function device replaces the first IP address with the third IP address in the first standard network, wherein the application function device Applied to the first system network and the second system network.
  • the ten notification message may further carry the second IP address, the fourth IP address, and fourth usage information, where the fourth usage information is used to indicate that the application function device is in the first
  • the fourth IP address is used in place of the second IP address in the standard network.
  • the AF device after receiving the tenth notification message, the AF device performs signaling plane communication with the terminal by using the third IP address or the fourth IP address (if any), and simultaneously accesses the forwarding and forwarding gateway ATGW.
  • Send an update user plane request message (for example: Update User Plane Request).
  • the update user plane request message is used to request the ATGW to update the first IP address of the user plane to the third IP address, or to request the ATGW to use the second side of the user plane.
  • the IP address is updated to the fourth IP address.
  • the AF device receives an update user plane request response message (for example, an Update User Plane Response) from the ATGW.
  • an update user plane request response message for example, an Update User Plane Response
  • the process of creating the second bearer is a live network process, and details are not described herein.
  • the first-standard network is a 4G network
  • the second-standard network is a 5G network
  • the first core network device is a mobility management entity MME of the 4G network
  • the second core network device is a control plane function of the 5G network.
  • the first access network device is an evolved base station eNB of the 4G network
  • the second access network device is a next-generation radio access network NG RAN entity of the 5G network
  • the first gateway is a serving gateway SGW of the 4G network
  • the second gateway is a PDN gateway PGW of the 4G network
  • the first policy device is a policy and charging rule function PCRF entity of the 4G network
  • the second policy device is a policy function Policy Function entity of the 5G network
  • the PCRF entity in the 4G network is The policy function of the 5G network is deployed independently.
  • the switching method disclosed in the embodiment of the present invention includes:
  • the terminal reports the neighbor cell signal measurement result to the NG RAN entity, and the NG RAN entity decides to switch the terminal from the 5G network to the 4G network.
  • the NG RAN entity sends a handover request message (for example, Handover Required) to the CP Function entity.
  • a handover request message for example, Handover Required
  • the CP Function entity After receiving the handover request message, the CP Function entity sends a first handover request (for example, Forward Relocation Request) to the MME.
  • a first handover request for example, Forward Relocation Request
  • a handover request carries: a first Internet Protocol IP address, and the first IP address is used for the establishment process of the first APN.
  • the terminal when the terminal further includes services such as VoLTE (LTE network voice service) and ViLTE (LTE network video service), in order to maintain the continuity of the service, a second APN needs to be established for the service.
  • a Dedicated APN such as an IMS APN
  • the first handover request may further carry: a second IP address of the terminal, where the second IP address is used to establish a second access point name APN.
  • the process, wherein the first IP address and the second IP address are IP addresses assigned by the 5G network to the terminal.
  • the first handover request may further carry at least one of the following:
  • An International Mobile Subscriber Identification Number (IMSI) of the terminal, a security context of the terminal, a mobility management context of the terminal, a session management class context of the terminal, and the terminal is at the first Terminal network capability information for a standard network.
  • IMSI International Mobile Subscriber Identification Number
  • the terminal network capability information can be obtained by the following two methods:
  • the terminal carries the terminal network capability information in an attach request message (for example, an Attach Request) sent to the CP Function entity.
  • an attach request message for example, an Attach Request
  • the CP Function entity sends a query request message Query Request to the terminal, and the terminal carries the terminal network capability information in a query request response message sent to the CP Function entity.
  • the MME after receiving the first handover request, the MME is the terminal in the 4G network.
  • the establishment process of the first access point name APN is initiated in the network.
  • the MME is a process for the terminal to initiate a second access point APN in the 4G network.
  • the MME sends a second handover request (for example, a Handover Request) to the eNB.
  • a second handover request for example, a Handover Request
  • the eNB After receiving the second handover request, the eNB sends a response message (eg, Handover Request Acknowledge) of the second handover request to the MME.
  • a response message eg, Handover Request Acknowledge
  • the MME after receiving the response message of the second handover request, the MME sends a response message (for example, Forward Relocation Response) of the first handover request to the CP Function entity, where the response message of the first handover request carries Said third IP address.
  • a response message for example, Forward Relocation Response
  • the response message of the first handover request carries at least one of the following:
  • An attach accept message carrying information of the first APN, the first IP address, the third IP address, and first usage information, where the first usage information is used to indicate that the terminal is Replacing the first IP address with the third IP address in the first standard network;
  • the packet data network PDN connection establishment accept message, the PDN connection establishment accept message carrying information of the second APN.
  • the CP Function entity after receiving the response message of the first handover request, the CP Function entity sends a handover request response message (for example, Handover Required Response) to the NG RAN entity.
  • a handover request response message for example, Handover Required Response
  • the handover request response message carries at least one of the following:
  • An attach accept message carrying information of the first APN, the first IP address, the third IP address, and first usage information, where the first usage information is used to indicate that the terminal is Replacing the first IP address with the third IP address in the first standard network;
  • the packet data network PDN connection establishment accept message, the PDN connection establishment accept message carrying information of the second APN.
  • the PDN connection establishment accept message further carries the second IP address, the fourth IP address, and second usage information, where the second usage information is used to indicate that the terminal is used in a first-standard network.
  • the fourth IP address replaces the second IP address.
  • the NG RAN entity after receiving the handover request response message, the NG RAN entity sends a handover command message (for example, a Handover Command) to the terminal.
  • a handover command message for example, a Handover Command
  • the handover command message carries at least one of the following: an attach accept message, a packet data network PDN connection setup accept message.
  • the attach accept message carries the information of the first APN, the first IP address, the third IP address, and the first use information, where the first use information is used to indicate that the terminal uses the in the 4G network.
  • the third IP address is used to replace the first IP address, and the PDN connection establishment accept message carries information that the MME is the second APN established by the terminal on the 4G network.
  • the PDN connection establishment accept message further carries the second IP address, the fourth IP address, and second usage information, where the second usage information is used to indicate that the terminal uses the 4G network.
  • the fourth IP address replaces the second IP address.
  • S3c10 The terminal sends a handover complete message (for example, Handover Complete) to the eNB entity.
  • a handover complete message for example, Handover Complete
  • the terminal after receiving the handover complete message, the terminal sends an eleventh notification message (for example, Notify11) to the AF device, where the terminal may send the to the AF device by using session initiation protocol SIP signaling.
  • the eleventh notification message for example, Notify11
  • the eleventh notification message is used to notify the AF device that the terminal switches from the 5G network to the 4G network, and the eleventh notification message carries the first IP address and the Determining a third IP address and third usage information, the third usage information being used to indicate that the application function device replaces the first IP address by using the third IP address in the first standard network, wherein the application A functional device is applied to the first system network and the second system network.
  • the eleventh notification message may further carry the second IP address, the fourth IP address, and fourth usage information, where the fourth usage information is used to indicate that the application function device is in the The fourth IP address is replaced with the second IP address in a standard network.
  • the AF device after receiving the eleventh notification message, the AF device performs signaling plane communication with the terminal by using the third IP address or the fourth IP address (if any), and simultaneously accesses the forwarding gateway.
  • the ATGW sends an update user plane request message (for example: Update User Plane Request).
  • the update user plane request message is used to request the ATGW to perform the first part of the user plane.
  • An IP address is updated to the third IP address, or is used to request the ATGW to update the second IP address of the user plane to the fourth IP address.
  • the AF device receives an update user plane request response message (for example, an Update User Plane Response) from the ATGW.
  • an update user plane request response message for example, an Update User Plane Response
  • the process of creating the second bearer is a live network process, and details are not described herein.
  • the first-standard network is a 4G network
  • the second-standard network is a 5G network
  • the first core network device is a mobility management entity MME of the 4G network
  • the second core network device is a control plane function of the 5G network.
  • the first access network device is an evolved base station eNB of the 4G network
  • the second access network device is a next-generation radio access network NG RAN entity of the 5G network
  • the first gateway is a serving gateway SGW of the 4G network
  • the second gateway is a PDN gateway PGW of the 4G network
  • the first policy device is a policy and charging rule function PCRF entity of the 4G network
  • the second policy device is a policy function Policy Function entity of the 5G network
  • the PCRF entity in the 4G network is The policy function of the 5G network is deployed independently.
  • the switching method disclosed in the embodiment of the present invention includes:
  • the terminal reports the neighbor cell signal measurement result to the NG RAN entity, and the NG RAN entity decides to switch the terminal from the 5G network to the 4G network.
  • the NG RAN entity sends a handover request message (for example, Handover Required) to the CP Function entity.
  • a handover request message for example, Handover Required
  • the CP Function entity After receiving the handover request message, the CP Function entity sends a first handover request (for example, Forward Relocation Request) to the MME.
  • a first handover request for example, Forward Relocation Request
  • a handover request carries: a first Internet Protocol IP address, and the first IP address is used for the establishment process of the first APN.
  • the terminal when the terminal further includes services such as VoLTE (LTE network voice service) and ViLTE (LTE network video service), in order to maintain the continuity of the service, a second APN needs to be established for the service.
  • a Dedicated APN such as an IMS APN
  • the first handover request may further carry: a second IP address of the terminal, where the second IP address is used for A process of establishing an access point name APN, wherein the first IP address and the second IP address are IP addresses allocated by the 5G network to the terminal.
  • the first handover request may further carry at least one of the following:
  • An International Mobile Subscriber Identification Number (IMSI) of the terminal, a security context of the terminal, a mobility management context of the terminal, a session management class context of the terminal, and the terminal is at the first Terminal network capability information for a standard network.
  • IMSI International Mobile Subscriber Identification Number
  • the terminal network capability information can be obtained by the following two methods:
  • the terminal carries the terminal network capability information in an attach request message (for example, an Attach Request) sent to the CP Function entity.
  • an attach request message for example, an Attach Request
  • the CP Function entity sends a query request message Query Request to the terminal, and the terminal carries the terminal network capability information in a query request response message sent to the CP Function entity.
  • the MME after receiving the first handover request, the MME initiates a process of establishing a first access point name APN in the 4G network.
  • the MME is a process for the terminal to initiate a second access point APN in the 4G network.
  • the MME sends a second handover request (for example, Handover Request) to the eNB.
  • a second handover request for example, Handover Request
  • S3d06 After receiving the second handover request, the eNB sends a response message (for example, Handover Request Acknowledge) of the second handover request to the MME.
  • a response message for example, Handover Request Acknowledge
  • the MME after receiving the response message of the second handover request, the MME sends a response message (for example, Forward Relocation Response) of the first handover request to the CP Function entity, where the response message of the first handover request carries Said third IP address.
  • a response message for example, Forward Relocation Response
  • the response message of the first handover request carries at least one of the following:
  • An attach accept message carrying information of the first APN, the first IP address, the third IP address, and first usage information, where the first usage information is used to indicate that the terminal is Replacing the first IP address with the third IP address in the first standard network;
  • the packet data network PDN connection establishment accept message, the PDN connection establishment accept message carrying information of the second APN.
  • the CP Function entity after receiving the response message of the first handover request, the CP Function entity sends a handover request response message (for example, Handover Required Response) to the NG RAN entity.
  • a handover request response message for example, Handover Required Response
  • the handover request response message carries at least one of the following:
  • An attach accept message carrying information of the first APN, the first IP address, the third IP address, and first usage information, where the first usage information is used to indicate that the terminal is Replacing the first IP address with the third IP address in the first standard network;
  • the packet data network PDN connection establishment accept message, the PDN connection establishment accept message carrying information of the second APN.
  • the PDN connection establishment accept message further carries the second IP address, the fourth IP address, and second usage information, where the second usage information is used to indicate that the terminal is used in a first-standard network.
  • the fourth IP address replaces the second IP address.
  • the NG RAN entity After receiving the handover request response message, the NG RAN entity sends a handover command message (for example, a Handover Command) to the terminal.
  • a handover command message for example, a Handover Command
  • the handover command message carries at least one of the following: an attach accept message, a packet data network PDN connection setup accept message.
  • the attach accept message carries the information of the first APN, the first IP address, the third IP address, and the first use information, where the first use information is used to indicate that the terminal uses the in the 4G network.
  • the third IP address is used to replace the first IP address, and the PDN connection establishment accept message carries information that the MME is the second APN established by the terminal on the 4G network.
  • the PDN connection establishment accept message further carries the second IP address, the fourth IP address, and second usage information, where the second usage information is used to indicate that the terminal uses the 4G network.
  • the fourth IP address replaces the second IP address.
  • S3d10 The terminal sends a handover complete message (for example, Handover Complete) to the eNB entity.
  • a handover complete message for example, Handover Complete
  • the terminal after receiving the handover complete message, the terminal initiates a second bearer creation process
  • the process of creating the second bearer is a live network process, and details are not described herein.
  • FIG. 4a is a possible implementation manner of the process of creating a second bearer by the AF device in the step 3a15 described in FIG. 3a, the second bearer setup process for the second IP address
  • the process of establishing the first bearer is the same as the process of establishing the first bearer of the first IP address.
  • the following takes the second IP address as an example to describe the specific process of establishing the second bearer, which specifically includes the following steps:
  • the AF device sends a service establishment request message to the Policy Function entity, that is, a setup request of the first bearer, and the service establishment request message carries a service request, before the terminal initiates the process of establishing the second bearer. information;
  • the first bearer is a bearer established by the service of the terminal in the 5G network, and when the terminal switches from the 5G network to the 4G network, in order to maintain service continuity, the 4G network is
  • the second bearer is established in the service of the terminal, and the step 1a is mainly to ensure that the AF device transmits the service requirement information to the Policy Function entity during the first bearer establishment process to ensure the 4G network.
  • the Policy Function entity directly initiates the establishment process of the second bearer for the service of the terminal by using the service requirement information.
  • the AF device searches for the service requirement information by using the first IP address of the 5G network, and after the third IP address of the 4G network is addressed to the PCRF entity, sends an authentication authorization request to the PCRF entity (Authentication Authorization) Request, AAR) message.
  • PCRF entity Authentication Authorization
  • the authentication authorization request message carries the third IP address.
  • the PCRF entity after receiving the authentication authorization request message, the PCRF entity addresses the PGW by using the third IP address, and sends a Re-authentication Request (RAR) message to the PGW.
  • RAR Re-authentication Request
  • the PGW after receiving the re-authentication request message, the PGW sends a Re-authentication Answer (RAA) message to the PCRF entity.
  • RAA Re-authentication Answer
  • the PCRF entity After receiving the RAA, the PCRF entity sends an Authentication Authorization Answer (AAA) message to the AF device.
  • AAA Authentication Authorization Answer
  • the PGW sends a bearer creation request message (for example, Create Bearer Request) to the MME by using the SGW.
  • a bearer creation request message for example, Create Bearer Request
  • S4a06 The SGW forwards the bearer creation request message to the MME.
  • S4a07-S4a09 corresponds to the steps S317-S319 in FIG. 3, and details are not described herein again.
  • the eNB entity After receiving the handover complete message, the eNB entity sends a completion message (for example, Handover to E-UTRAN Complete) to the MME entity to switch to the 4G network.
  • a completion message for example, Handover to E-UTRAN Complete
  • the MME entity After receiving the completion message Handover to E-UTRAN Complete from the eNB entity to the 4G network, the MME entity sends a bearer setup request message (for example, Bearer Setup Request) to the eNB entity.
  • a bearer setup request message for example, Bearer Setup Request
  • the eNB entity After receiving the bearer setup message, the eNB entity sends a radio resource control connection reset message (for example, RRC Connection Reconfiguration) to the terminal.
  • a radio resource control connection reset message for example, RRC Connection Reconfiguration
  • the terminal After receiving the radio resource control connection reset message, the terminal sends a radio resource control connection reset complete message (for example, RRC Connection Reconfiguration Complete) to the eNB entity.
  • a radio resource control connection reset complete message for example, RRC Connection Reconfiguration Complete
  • the eNB After receiving the radio resource control connection reset complete message, the eNB sends a bearer setup response message (for example, a Bearer Setup Response message) to the MME entity.
  • a bearer setup response message for example, a Bearer Setup Response message
  • the MME After receiving the bearer setup response message, the MME sends a bearer creation response message (for example, Create Bearer Response) to the SGW.
  • a bearer creation response message for example, Create Bearer Response
  • S4a16 The SGW sends a bearer creation response message to the PGW-C.
  • the first-standard network is a 4G network
  • the second-standard network is a 5G network
  • the first core network device is a mobility management entity MME of the 4G network
  • the second core network device is a control plane function of the 5G network.
  • the first access network device is an evolved base station eNB of the 4G network
  • the second access network device is a next-generation radio access network NG RAN entity of the 5G network
  • the first gateway is a serving gateway SGW of the 4G network
  • the second gateway is a PDN gateway PGW of the 4G network
  • the first policy device is a policy and charging rule function PCRF entity of the 4G network
  • the second policy device is a policy function Policy Function entity of the 5G network
  • the PCRF entity in the 4G network is When the policy function of the 5G network is deployed in a unified manner, the switching method disclosed in the embodiment of the present invention specifically includes the following steps:
  • the terminal reports the neighbor cell signal measurement result to the NG RAN entity, and the NG RAN entity decides to switch the terminal from the 5G network to the 4G network.
  • the NG RAN entity sends a handover request message (for example, Handover Required) to the CP Function entity.
  • a handover request message for example, Handover Required
  • the CP Function entity After receiving the handover request message, the CP Function entity sends a first handover request (for example, Forward Relocation Request) to the MME.
  • a first handover request for example, Forward Relocation Request
  • a handover request carries: a first Internet Protocol IP address, and the first IP address is used for the establishment process of the first APN.
  • the terminal when the terminal further includes services such as VoLTE (LTE network voice service) and ViLTE (LTE network video service), in order to maintain the continuity of the service, a second APN needs to be established for the service.
  • a Dedicated APN such as an IMS APN
  • the first handover request may further carry: a second IP address of the terminal, where the second IP address is used to establish a second access point name APN.
  • the process, wherein the first IP address and the second IP address are IP addresses assigned by the 5G network to the terminal.
  • the first handover request may further carry at least one of the following:
  • An International Mobile Subscriber Identification Number (IMSI) of the terminal, a security context of the terminal, a mobility management context of the terminal, a session management class context of the terminal, and the terminal is at the first Terminal network capability information for a standard network.
  • IMSI International Mobile Subscriber Identification Number
  • the terminal network capability information can be obtained by the following two methods:
  • the terminal carries the terminal network capability information in an attach request message (for example, an Attach Request) sent to the CP Function entity.
  • an attach request message for example, an Attach Request
  • the CP Function entity sends a query request message Query Request to the terminal, and the terminal carries the terminal network capability information in a query request response message sent to the CP Function entity.
  • the MME after receiving the first handover request, the MME initiates a process of establishing a first access point name APN in the 4G network.
  • the MME is that the terminal initiates a second access point APN in the 4G network.
  • the establishment process is that the terminal initiates a second access point APN in the 4G network.
  • the MME sends a second handover request (for example, a Handover Request) to the eNB.
  • a second handover request for example, a Handover Request
  • the eNB After receiving the second handover request, the eNB sends a response message (for example, Handover Request Acknowledge) of the second handover request to the MME.
  • a response message for example, Handover Request Acknowledge
  • the MME after receiving the response message of the second handover request, the MME sends a response message (for example, Forward Relocation Response) of the first handover request to the CP Function entity, where the response message of the first handover request carries Said third IP address.
  • a response message for example, Forward Relocation Response
  • the response message of the first handover request carries at least one of the following:
  • An attach accept message carrying information of the first APN, the first IP address, the third IP address, and first usage information, where the first usage information is used to indicate that the terminal is Replacing the first IP address with the third IP address in the first standard network;
  • the packet data network PDN connection establishment accept message, the PDN connection establishment accept message carrying information of the second APN.
  • the CP Function entity after receiving the first handover request response, the CP Function entity sends a seventh notification message (for example, Notify7) to the Policy Function entity.
  • a seventh notification message for example, Notify7
  • the seventh notification message is used to notify the Policy Function entity that the terminal switches from the 5G network to the 4G network, and the seventh notification message carries the first IP address, the a third IP address and a third usage information, the third usage information being used to indicate that the application function device replaces the first IP address by using the third IP address in the first standard network, wherein the application function The device is applied to the first system network and the second system network.
  • the seven notification message may further carry the second IP address, the fourth IP address, and fourth usage information, where the fourth usage information is used to indicate that the application function device is in the first
  • the fourth IP address is used in place of the second IP address in the standard network.
  • the first handover request in the step S5a02 may not carry the a first IP address or the second IP address, but directly carrying an address of the CP Function, where the address of the CP Function is used for the first step in step S5a03 Addressing the CP Function entity during the establishment of the second APN in step S5a04 during the establishment of the APN, in which case the CP Function entity receives the first handover request response,
  • the Policy Function entity sends the seventh notification message Notify7.
  • the Policy Function entity after receiving the seventh notification message, the Policy Function entity sends an eighth notification message (for example, Notify8) to the AF device.
  • an eighth notification message for example, Notify8
  • the eighth notification message is used to notify the AF device that the terminal switches from the 5G network to the 4G network, and the eighth notification message carries the first IP address, the first a third IP address and a third usage information, the third usage information being used to indicate that the application function device replaces the first IP address with the third IP address in the first standard network, wherein the application function device Applied to the first system network and the second system network.
  • the eight notification message may further carry the second IP address, the fourth IP address, and fourth usage information, where the fourth usage information is used to indicate that the application function device is in the first
  • the fourth IP address is used in place of the second IP address in the standard network.
  • the AF device after receiving the eighth notification message, performs signaling plane communication with the terminal by using the third IP address or the fourth IP address (if any), and simultaneously accesses the forwarding and forwarding gateway ATGW.
  • Send an update user plane request message (for example: Update User Plane Request).
  • the update user plane request message is used to request the ATGW to update the first IP address of the user plane to the third IP address, or to request the ATGW to use the second side of the user plane.
  • the IP address is updated to the fourth IP address.
  • the AF device receives an update user plane request response message (for example, an Update User Plane Response) from the ATGW.
  • an update user plane request response message for example, an Update User Plane Response
  • the first-standard network is a 4G network
  • the second-standard network is a 5G network
  • the first core network device is a mobility management entity MME of the 4G network
  • the second core network device is a control plane function of the 5G network.
  • a CP function entity the first access network device is an evolved base station eNB of the 4G network
  • the second access network device is a next-generation radio access network NG RAN entity of the 5G network
  • the gateway is the serving gateway SGW of the 4G network
  • the second gateway is the PDN gateway PGW of the 4G network
  • the first policy device is the policy and charging rule function PCRF entity of the 4G network
  • the second policy device is the policy function of the 5G network.
  • the terminal reports the neighbor cell signal measurement result to the NG RAN entity, and the NG RAN entity decides to switch the terminal from the 5G network to the 4G network.
  • the NG RAN entity sends a handover request message (for example, Handover Required) to the CP Function entity.
  • a handover request message for example, Handover Required
  • the CP Function entity after receiving the handover request message, the CP Function entity sends a first handover request (for example, Forward Relocation Request) to the MME.
  • a first handover request for example, Forward Relocation Request
  • a handover request carries: a first Internet Protocol IP address, and the first IP address is used for the establishment process of the first APN.
  • the terminal when the terminal further includes services such as VoLTE (LTE network voice service) and ViLTE (LTE network video service), in order to maintain the continuity of the service, a second APN needs to be established for the service.
  • a Dedicated APN such as an IMS APN
  • the first handover request may further carry: a second IP address of the terminal, where the second IP address is used to establish a second access point name APN.
  • the process, wherein the first IP address and the second IP address are IP addresses assigned by the 5G network to the terminal.
  • the first handover request may further carry at least one of the following:
  • An International Mobile Subscriber Identification Number (IMSI) of the terminal, a security context of the terminal, a mobility management context of the terminal, a session management class context of the terminal, and the terminal is at the first Terminal network capability information for a standard network.
  • IMSI International Mobile Subscriber Identification Number
  • the terminal network capability information can be obtained by the following two methods:
  • Path 1 the connection request message sent by the terminal to the CP Function entity (for example: The terminal network capability information is carried in the Attach Request.
  • the CP Function entity sends a query request message Query Request to the terminal, and the terminal carries the terminal network capability information in a query request response message sent to the CP Function entity.
  • the MME after receiving the first handover request, the MME initiates a process of establishing a first access point name APN in the 4G network.
  • the MME is a process for the terminal to initiate a second access point APN in the 4G network.
  • the MME sends a second handover request (for example, Handover Request) to the eNB.
  • a second handover request for example, Handover Request
  • the eNB after receiving the second handover request, the eNB sends a response message (for example, Handover Request Acknowledge) of the second handover request to the MME.
  • a response message for example, Handover Request Acknowledge
  • the MME after receiving the response message of the second handover request, the MME sends a response message (for example, Forward Relocation Response) of the first handover request to the CP Function entity, where the response message of the first handover request carries Said third IP address.
  • a response message for example, Forward Relocation Response
  • the response message of the first handover request carries at least one of the following:
  • An attach accept message carrying information of the first APN, the first IP address, the third IP address, and first usage information, where the first usage information is used to indicate that the terminal is Replacing the first IP address with the third IP address in the first standard network;
  • the packet data network PDN connection establishment accept message, the PDN connection establishment accept message carrying information of the second APN.
  • the CP Function entity after receiving the response message of the first handover request, the CP Function entity sends a handover request response message (for example, Handover Required Response) to the NG RAN entity.
  • a handover request response message for example, Handover Required Response
  • the handover request response message carries at least one of the following:
  • An attach accept message carrying information of the first APN, the first IP address, the third IP address, and first usage information, where the first usage information is used to indicate that the terminal is Replacing the first IP address with the third IP address in the first standard network;
  • the packet data network PDN connection establishment accept message, the PDN connection establishment accept message carrying information of the second APN.
  • the PDN connection establishment accept message further carries the second IP address, the fourth IP address, and second usage information, where the second usage information is used to indicate that the terminal is used in a first-standard network.
  • the fourth IP address replaces the second IP address.
  • the NG RAN entity after receiving the handover request response message, the NG RAN entity sends a handover command message (for example, a Handover Command) to the terminal.
  • a handover command message for example, a Handover Command
  • the handover command message carries at least one of the following: an attach accept message, a packet data network PDN connection setup accept message.
  • the attach accept message carries the information of the first APN, the first IP address, the third IP address, and the first use information, where the first use information is used to indicate that the terminal uses the in the 4G network.
  • the third IP address is used to replace the first IP address, and the PDN connection establishment accept message carries information that the MME is the second APN established by the terminal on the 4G network.
  • the PDN connection establishment accept message further carries the second IP address, the fourth IP address, and second usage information, where the second usage information is used to indicate that the terminal uses the 4G network.
  • the fourth IP address replaces the second IP address.
  • S5b10 The terminal sends a handover complete message (for example, Handover Complete) to the eNB entity.
  • a handover complete message for example, Handover Complete
  • the eNB entity after receiving the handover complete message, the eNB entity sends a completion message (for example, Handover to E-UTRAN Complete) to the MME entity to switch to the 4G network;
  • a completion message for example, Handover to E-UTRAN Complete
  • the MME entity after receiving the completion message of the handover to the 4G network, the MME entity sends a handover completion notification message (for example, Forward Relocation Complete Notification) to the CP Function entity.
  • a handover completion notification message for example, Forward Relocation Complete Notification
  • the CP Function entity After receiving the handover completion notification message, the CP Function entity sends a handover complete acknowledgement message (for example, Forward Relocation Complete Acknowledge) to the MME entity.
  • a handover complete acknowledgement message for example, Forward Relocation Complete Acknowledge
  • S5b14 After sending the handover complete confirmation message, the CP Function entity sends a ninth notification message (for example, Notify9) to the Policy Function entity.
  • a ninth notification message for example, Notify9
  • the ninth notification message is used to notify the Policy Function entity that the terminal switches from the 5G network to the 4G network, and the ninth notification message carries the first IP address, the a third IP address and a third usage information, the third usage information being used to indicate that the application function device replaces the first IP address by using the third IP address in the first standard network, wherein the application function The device is applied to the first system network and the second system network.
  • the nine notification message may further carry the second IP address, the fourth IP address, and fourth usage information, where the fourth usage information is used to indicate that the application function device is in the first
  • the fourth IP address is used in place of the second IP address in the standard network.
  • the first handover request in the step S5b02 may not carry the a first IP address or the second IP address, but directly carrying the address of the CP Function, where the address of the CP Function is used in the process of establishing the first APN in step S5a03, in step S5a04 Addressing the CP Function entity in the process of establishing the second APN, in which case the CP Function entity sends the ninth notification message Notify9 to the Policy Function entity after sending the handover completion acknowledgement message. .
  • the Policy Function entity After receiving the ninth notification message, the Policy Function entity sends a tenth notification message (for example, Notify10) to the AF device.
  • a tenth notification message for example, Notify10
  • the tenth notification message is used to notify the AF device that the terminal switches from the 5G network to the 4G network, and the tenth notification message carries the first IP address, the first a third IP address and a third usage information, the third usage information being used to indicate that the application function device replaces the first IP address with the third IP address in the first standard network, wherein the application function device Applied to the first system network and the second system network.
  • the ten notification message may further carry the second IP address, the fourth IP address, and fourth usage information, where the fourth usage information is used to indicate that the application function device is in the first
  • the fourth IP address is used in place of the second IP address in the standard network.
  • the AF device after receiving the tenth notification message, the AF device performs signaling plane communication with the terminal by using the third IP address or the fourth IP address (if any), and simultaneously accesses the forwarding and forwarding gateway ATGW.
  • Send an update user plane request message (for example: Update User Plane Request).
  • the update user plane request message is used to request the ATGW to update the first IP address of the user plane to the third IP address, or to request the ATGW to use the second side of the user plane.
  • the IP address is updated to the fourth IP address.
  • the AF device receives an update user plane request response message (for example, an Update User Plane Response) from the ATGW.
  • an update user plane request response message for example, an Update User Plane Response
  • FIG. 6a is a possible implementation manner of the process of creating a second dedicated bearer in the step 5a12 described in FIG. 5a, the second bearer setup process for the second IP address, and The process of establishing the first bearer of the first IP address is the same.
  • the following takes the second IP address as an example to describe the specific process of establishing the second bearer.
  • the specific steps include the following steps:
  • the Policy Function entity receives a service establishment request message from the AF device, that is, a setup request of the first bearer, where the service establishment request message carries the service request information;
  • the first bearer is a bearer established by the service of the terminal in the 5G network, and when the terminal switches from the 5G network to the 4G network, in order to maintain the continuity of the service,
  • the step 1a is mainly to ensure that the policy function entity receives the service request information from the AF entity during the first bearer setup process, and ensures that the service request information is ensured.
  • the Policy Function entity may directly initiate the second bearer for the service of the terminal by using the service requirement information. The establishment process.
  • the Policy Function entity searches for the service requirement information through the first IP address of the 5G network, and addresses the PGW through the third IP address of the 4G network, and sends a re-authentication request message to the PGW.
  • the PGW sends a bearer creation request message to the SGW (for example: Create Bearer Request).
  • S6a04 The SGW forwards the bearer creation request message to the MME.
  • the eNB entity after receiving the handover complete message, the eNB entity sends a completion message (for example, Handover to E-UTRAN Complete) to the MME entity to switch to the 4G network.
  • a completion message for example, Handover to E-UTRAN Complete
  • the MME entity after receiving the completion message Handover to E-UTRAN Complete from the eNB entity to the 4G network, the MME entity sends a bearer setup request message (for example, Bearer Setup Request) to the eNB entity.
  • a bearer setup request message for example, Bearer Setup Request
  • the eNB entity After receiving the bearer setup message, the eNB entity sends a radio resource control connection reset message (for example, RRC Connection Reconfiguration) to the terminal.
  • a radio resource control connection reset message for example, RRC Connection Reconfiguration
  • the terminal After receiving the radio resource control connection reset message, the terminal sends a radio resource control connection reset complete message (for example, RRC Connection Reconfiguration Complete) to the eNB entity.
  • a radio resource control connection reset complete message for example, RRC Connection Reconfiguration Complete
  • Bearer Setup Response After receiving the RRC connection reset complete message, the eNB sends a bearer setup response message message (for example, Bearer Setup Response) to the MME entity.
  • a bearer setup response message message for example, Bearer Setup Response
  • the MME After receiving the bearer setup response message, the MME sends a bearer creation response message (for example, Create Bearer Response) to the SGW.
  • a bearer creation response message for example, Create Bearer Response
  • S6a14 The SGW sends a bearer creation response message to the PGW-C.
  • FIG. 6b is a possible implementation manner of the process of creating a second dedicated bearer of the step 5b18 described in FIG. 5b, the second bearer establishment process for the second IP address, and the The process of establishing the first bearer of an IP address is the same.
  • the following takes the second IP address as an example to describe the specific process of establishing the second bearer.
  • the specific steps include the following steps:
  • the Policy Function entity receives a service establishment request message from the AF device, that is, a setup request of the first bearer, where the service establishment request message carries the service request information;
  • the first bearer is a bearer established by the service of the terminal in the 5G network, and when the terminal switches from the 5G network to the 4G network, in order to maintain the continuity of the service,
  • the 4G network establishes a second bearer for the service of the terminal, and the 1a step is mainly for guaranteeing
  • the Policy Function entity receives the service request information from the AF entity, and ensures that when the PCRF entity in the 4G network and the Policy Function entity in the 5G network are deployed together,
  • the policy function entity may directly initiate the establishment process of the second bearer for the service of the terminal by using the service requirement information.
  • the Policy Function entity searches for the service requirement information through the first IP address of the 5G network, and addresses the PGW through the third IP address of the 4G network, and sends a re-authentication request message to the PGW.
  • the PGW sends a bearer creation request message (for example, Create Bearer Request) to the SGW.
  • a bearer creation request message for example, Create Bearer Request
  • the SGW forwards the bearer creation request message to the MME.
  • the MME entity sends a bearer setup request message (for example, Bearer Setup Request) to the eNB entity.
  • a bearer setup request message for example, Bearer Setup Request
  • the eNB entity after receiving the bearer setup message, the eNB entity sends a radio resource control connection reset message (for example, RRC Connection Reconfiguration) to the terminal.
  • a radio resource control connection reset message for example, RRC Connection Reconfiguration
  • the terminal after receiving the radio resource control connection reset message, the terminal sends a radio resource control connection reset complete message (for example, RRC Connection Reconfiguration Complete) to the eNB entity.
  • a radio resource control connection reset complete message for example, RRC Connection Reconfiguration Complete
  • the eNB after receiving the RRC connection reset complete message, the eNB sends a bearer setup response message message (for example, Bearer Setup Response) to the MME entity.
  • a bearer setup response message message for example, Bearer Setup Response
  • the MME After receiving the bearer setup response message, the MME sends a bearer creation response message (for example, Create Bearer Response) to the SGW.
  • a bearer creation response message for example, Create Bearer Response
  • S6b10 The SGW sends a bearer creation response message to the PGW-C.
  • FIG. 7 is a possible implementation manner of the process of establishing the first APN according to the embodiment of the present invention.
  • the establishment process of the APN specifically includes the following steps.
  • the MME sends a location update request message to the home subscriber server HSS (for example: Update Location Request).
  • HSS home subscriber server
  • the HSS After receiving the location update request message, the HSS sends a location update confirmation message (for example, an Update Location Response) to the MME.
  • a location update confirmation message for example, an Update Location Response
  • steps S701 and S702 are optional steps.
  • the first Internet Protocol IP address of the 5G network is used to initiate the establishment process of the first access point name APN, and the first create session request is sent to the SGW. (Example: Create Session Request1).
  • the SGW After receiving the first create session request, the SGW sends a third create session request (for example, Create Session Request3) to the PGW.
  • a third create session request for example, Create Session Request3
  • the PGW After receiving the third create session request, the PGW allocates a third IP address to the terminal in the 4G network, and then sends a first credit control request message CCR1 to the PCRF entity, where the request is the third The IP address establishes an IP connectivity access network session.
  • the PCRF entity After receiving the CCR1, the PCRF entity sends a first credit control response message (for example, CCA1) to the PGW.
  • a first credit control response message for example, CCA1
  • the PGW After receiving the first credit control response message, the PGW sends a third create session response (for example, Create Session Response3) to the SGW.
  • a third create session response for example, Create Session Response3
  • the third creation session response includes the third IP address, and the third creation session response carries information indicating that the terminal uses the third IP address.
  • the SGW After receiving the third create session response, the SGW sends a first create session response (eg, Create Session Response1) to the MME.
  • a first create session response eg, Create Session Response1
  • the first creation session response includes the third IP address, and the first creation session response carries information indicating that the terminal uses the third IP address.
  • FIG. 8 is a possible implementation manner of the process of establishing the second APN according to the embodiment of the present invention.
  • the establishment process of the APN specifically includes the following steps.
  • the MME sends a second creation session request (for example, Create Session Request2) to the SGW according to the second IP address to initiate a second APN establishment process.
  • a second creation session request for example, Create Session Request2
  • the SGW After receiving the second create session request, the SGW sends a fourth to the PGW. Create a session request (for example: Create Session Request4).
  • the PGW After receiving the fourth create session request, the PGW allocates a fourth IP address to the terminal in the 4G network, and then sends a second credit control request message (for example, CCR2) to the PCRF, where the request is The fourth IP address establishes an IP connectivity access network session.
  • a second credit control request message for example, CCR2
  • the PCRF entity After receiving the second credit control request message, the PCRF entity sends a second credit control response message (for example, CCA2) to the PGW.
  • a second credit control response message for example, CCA2
  • the PGW After receiving the second credit control response message, the PGW sends a fourth create session response (eg, Create Session Response 4) to the SGW.
  • a fourth create session response eg, Create Session Response 4
  • the fourth creation session response includes the fourth IP address, and the fourth creation session response carries information indicating that the terminal uses the fourth IP address.
  • the SGW After receiving the fourth create session response, the SGW sends a second create session response (for example, Create Session Response2) to the MME.
  • a second create session response for example, Create Session Response2
  • the second creation session response includes the fourth IP address, and the second creation session response carries the information indicating that the terminal uses the fourth IP address.
  • each network element such as the first core network device, the second core network device, the second access network device, the terminal, etc.
  • each network element such as the first core network device, the second core network device, the second access network device, the terminal, etc.
  • each network element includes corresponding hardware structures and/or software for executing each function.
  • Module includes corresponding hardware structures and/or software for executing each function.
  • the present invention can be implemented in a combination of hardware or hardware and computer software in combination with the elements and algorithm steps of the various examples described in the embodiments disclosed herein. Whether a function is implemented in hardware or computer software to drive hardware depends on the specific application and design constraints of the solution. A person skilled in the art can use different methods for implementing the described functions for each particular application, but such implementation should not be considered to be beyond the scope of the present invention.
  • the embodiments of the present invention may perform functional unit division on the first core network device, the first core network device, the second access network device, the terminal, and the like according to the foregoing method.
  • each functional unit may be divided according to each function, or Integrate two or more functions into one processing unit.
  • the above integrated unit can be implemented in the form of hardware or in the form of a software functional unit. It should be noted that the division of the unit in the embodiment of the present invention is schematic, only one type The logical function is divided, and there may be another way of dividing the actual implementation.
  • FIG. 9A shows a possible structural diagram of the first core network device involved in the above embodiment.
  • the first core network device 900 includes a processing unit 902 and a communication unit 903.
  • the processing unit 902 is configured to perform control management on the action of the first core network device.
  • the processing unit 902 is configured to support the first core network device to perform 203, 204, 205, and 206 in FIG. 2, step S303 in FIG. S304, S307, S308, S314, S316, step S407 in Fig. 4, steps S503, S504, S507, S508, S514, S516 in Fig. 5, S605 in Fig. 6, steps S701, S703 in Fig.
  • the communication unit 903 is configured to support communication between the first core network device and other network entities, such as communication with the eNB, SGW, etc. shown in FIG.
  • the first core network device may further include a storage unit 901 for storing program codes and data of the MME.
  • the processing unit 902 can be a processor or a controller, and can be, for example, a central processing unit (CPU), a general-purpose processor, a digital signal processor (DSP), and an application-specific integrated circuit (Application-Specific). Integrated Circuit (ASIC), Field Programmable Gate Array (FPGA) or other programmable logic device, transistor logic device, hardware component, or any combination thereof. It is possible to implement or carry out the various illustrative logical blocks, modules and circuits described in connection with the present disclosure.
  • the processor may also be a combination of computing functions, for example, including one or more microprocessor combinations, a combination of a DSP and a microprocessor, and the like.
  • the communication unit 903 may be a communication interface, a transceiver, a transceiver circuit, or the like.
  • the communication interface is a generic name and may include one or more interfaces.
  • the communication interface may include an interface between the MME and the SGW, and an interface between the MME and the eNB. / or other interface.
  • the storage unit 901 can be a memory.
  • the processing unit 902 is a processor
  • the communication unit 903 is a communication interface
  • the storage unit 901 is The MME according to the embodiment of the present invention may be the MME shown in FIG. 9B.
  • the first core network device 910 includes a processor 912, a communication interface 913, and a memory 911.
  • the first core network device 910 may further include a bus 914.
  • the communication interface 913, the processor 912, and the memory 911 may be connected to each other through a bus 914.
  • the bus 914 may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (abbreviated). EISA) bus and so on.
  • PCI Peripheral Component Interconnect
  • EISA Extended Industry Standard Architecture
  • the bus 914 can be divided into an address bus, a data bus, a control bus, and the like. For ease of representation, only one thick line is shown in Figure 9B, but it does not mean that there is only one bus or one type of bus.
  • the first core network device shown in FIG. 9A or FIG. 9B can also be understood as a device for the first core network device, which is not limited in the embodiment of the present invention.
  • FIG. 10A shows a possible structural diagram of the second core network device involved in the above embodiment.
  • the second core network device 1000 includes a processing unit 1002 and a communication unit 1003.
  • the processing unit 1002 is configured to control and control the action of the second core network device.
  • the processing unit 1002 is configured to support the second core network device to perform 202, 207 in FIG. 2, and steps S302, S305, and S309 in FIG. S317, steps S502, S505, S509, S517 in Fig. 5, steps S3a02, S3a08 in Fig. 3a, steps S3b02, S3b08, S3b13, S3b14 in Fig.
  • the communication unit 1003 is configured to support communication between the second core network device and other network entities, such as communication with the NG RAN entity, the UP Function entity, and the like shown in FIG.
  • the second core network device may further include a storage unit 1001 for storing program codes and data of the second core network device.
  • the processing unit 1002 may be a processor or a controller, such as a central processing unit (CPU), a general-purpose processor, a digital signal processor (DSP), and an application-specific integrated circuit (Application-Specific). Integrated Circuit (ASIC), Field Programmable Gate Array (FPGA) or other programmable logic device, transistor logic device, hardware component, or any combination thereof. It is possible to implement or carry out the various illustrative logical blocks, modules and circuits described in connection with the present disclosure.
  • the processor It can also be a combination of computing functions, such as one or more microprocessor combinations, a combination of a DSP and a microprocessor, and the like.
  • the communication unit 1003 may be a communication interface, a transceiver, a transceiver circuit, etc., wherein the communication interface is a generic name, and may include one or more interfaces, for example, may include: an interface between a CP Function entity and an NG RAN entity, and a CP Function entity and Interfaces and/or other interfaces between UP Function entities.
  • the storage unit 1001 may be a memory.
  • the second core network device may be the second core network device shown in FIG. 10B.
  • the second core network device 1010 includes a processor 1010, a communication interface 1013, and a memory 1011.
  • the second core network device 1010 may further include a bus 1014.
  • the communication interface 1013, the processor 1010, and the memory 1011 may be connected to each other through a bus 1014.
  • the bus 1014 may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (abbreviated). EISA) bus and so on.
  • PCI Peripheral Component Interconnect
  • EISA Extended Industry Standard Architecture
  • the bus 1014 can be divided into an address bus, a data bus, a control bus, and the like. For ease of representation, only one thick line is shown in FIG. 10B, but it does not mean that there is only one bus or one type of bus.
  • the second core network device shown in FIG. 10A or FIG. 10B can also be understood as a device for the CP Function entity, which is not limited in the embodiment of the present invention.
  • FIG. 11A shows a possible structural diagram of the second access network device involved in the above embodiment.
  • the second access network device 1100 includes a processing unit 1102, a first communication unit 1103, and a second communication unit 1104.
  • the processing unit 1102 is configured to perform control management on the action of the second access network device.
  • the processing unit 1102 is configured to support the second access network device to perform steps 201, 207, and 208 in FIG. 2 and/or Other processes of the described technology.
  • the first communication unit 1103 is configured to support communication between the second access network device 1100 and other access network devices or core network devices.
  • the second communication unit 1104 is configured to support communication between the second access network device and the terminal.
  • the second access network device may further include a storage unit 1101 for storing program codes and data of the second access network device.
  • the processing unit 1102 can be a processor or a controller, for example, can be a central processing unit. (Central Processing Unit, CPU), general purpose processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), Field Programmable Gate Array (FPGA) Or other programmable logic device, transistor logic device, hardware component, or any combination thereof. It is possible to implement or carry out the various illustrative logical blocks, modules and circuits described in connection with the present disclosure.
  • the processor may also be a combination of computing functions, for example, including one or more microprocessor combinations, a combination of a DSP and a microprocessor, and the like.
  • the first communication unit 1103 may be a communication interface, where the communication interface is a collective name.
  • the communication interface may include multiple interfaces, for example, may include: an interface between the access network device and the access network device, An interface and/or other interface between the access network device and the core network device.
  • the second communication unit 1104 may be a transceiver or a transceiver circuit or the like.
  • the storage unit 1101 may be a memory.
  • the second access network device When the processing unit 1102 is a processor, the first communication unit 1103 is a communication interface, the second communication unit 1104 is a transceiver, and the storage unit 1101 is a memory, the second access network device according to the embodiment of the present invention may be FIG. 11B. The second access network device shown.
  • the second access network device 1110 includes a processor 1112, a communication interface 1113, a transceiver 1114, and a memory 1111.
  • the second access network device 1110 may further include a bus 1115.
  • the communication interface 1113, the transceiver 1114, the processor 1112, and the memory 1111 may be connected to each other through a bus 1115;
  • the bus 1115 may be a Peripheral Component Interconnect (PCI) bus or an extended industry standard structure (Extended Industry) Standard Architecture (EISA) bus, etc.
  • PCI Peripheral Component Interconnect
  • EISA Extended Industry Standard Architecture
  • the bus 1115 can be divided into an address bus, a data bus, a control bus, and the like. For ease of representation, only one thick line is shown in FIG. 11B, but it does not mean that there is only one bus or one type of bus.
  • the second access network device shown in FIG. 11A or FIG. 11B can also be understood as a device for the NG RAN entity, which is not limited in the embodiment of the present invention.
  • FIG. 12A shows a possible structural diagram of the terminal involved in the above embodiment.
  • the terminal 1200 includes a processing unit 1202 and a communication unit 1203.
  • the processing unit 1202 is configured to control and manage the actions of the terminal.
  • the processing unit 1202 is configured to support the terminal to perform steps 209 and 210 in FIG. 2 and/or other processes for the techniques described herein.
  • Communication unit 1203 is used to support communication between the terminal and other network entities, such as with the NG RAN entity shown in FIG.
  • the terminal may further include a storage unit 1201 for storing program codes and data of the terminal.
  • the processing unit 1202 may be a processor or a controller, such as a central processing unit (CPU), a general-purpose processor, a digital signal processor (DSP), and an application-specific integrated circuit (Application-Specific). Integrated Circuit (ASIC), Field Programmable Gate Array (FPGA) or other programmable logic device, transistor logic device, hardware component, or any combination thereof. It is possible to implement or carry out the various illustrative logical blocks, modules and circuits described in connection with the present disclosure.
  • the processor may also be a combination of computing functions, for example, including one or more microprocessor combinations, a combination of a DSP and a microprocessor, and the like.
  • the communication unit 1203 may be a transceiver, a transceiver circuit, or a communication, etc., wherein the communication interface is a collective name and may include one or more interfaces.
  • the storage unit 1201 may be a memory.
  • the terminal involved in the embodiment of the present invention may be the terminal shown in FIG. 12B.
  • the terminal 1210 includes a processor 1212, a transceiver 1213, and a memory 1211.
  • the terminal 1210 may further include a bus 1214.
  • the transceiver 1213, the processor 1212, and the memory 1211 may be connected to each other through a bus 1214.
  • the bus 1214 may be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (abbreviated). EISA) bus and so on.
  • PCI Peripheral Component Interconnect
  • EISA Extended Industry Standard Architecture
  • the bus 1214 can be divided into an address bus, a data bus, a control bus, and the like. For ease of representation, only one thick line is shown in Figure 12B, but it does not mean that there is only one bus or one type of bus.
  • the terminal shown in FIG. 12A or FIG. 12B can also be understood as a device for a terminal, which is not limited in the embodiment of the present invention.
  • the embodiment of the present invention also provides the following device: a first gateway, a second gateway, a first access network device, a first policy device, a second policy device, an application function device, etc.
  • a schematic structural diagram of the first core network device or the foregoing second core network device or the second access network device is not described in detail in the embodiment of the present invention.
  • the steps of the method or algorithm described in the embodiments of the present invention may be implemented in a hardware manner, or may be implemented by a processor executing software instructions.
  • the software instructions may be composed of corresponding software modules, which may be stored in a random access memory (RAM), a flash memory, a read only memory (ROM), an erasable programmable read only memory ( Erasable Programmable ROM (EPROM), electrically erasable programmable read only memory (EEPROM), registers, hard disk, removable hard disk, compact disk read only (CD-ROM) or any other form of storage medium known in the art.
  • An exemplary storage medium is coupled to the processor to enable the processor to read information from, and write information to, the storage medium.
  • the storage medium can also be an integral part of the processor.
  • the processor and the storage medium can be located in an ASIC. Additionally, the ASIC can be located in a gateway device or mobility management network element. Of course, the processor and the storage medium may also exist as discrete components in the gateway device or the mobility management network
  • the functions described in the embodiments of the present invention may be implemented in hardware, software, firmware, or any combination thereof.
  • the functions may be stored in a computer readable medium or transmitted as one or more instructions or code on a computer readable medium.
  • Computer readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one location to another.
  • a storage medium may be any available media that can be accessed by a general purpose or special purpose computer.

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Abstract

本发明实施例提供一种切换方法及设备，包括：第一核心网设备从第二核心网设备接收第一切换请求，第一切换请求携带第一IP地址，第一IP地址为第二制式网络为终端分配的IP地址；第一核心网设备为终端在第一制式网络中根据第一IP地址发起第一APN的建立过程，第一核心网设备在第一APN的建立过程中获取第一制式网络为终端分配的第三IP地址；第一核心网设备向接入网设备发送第二切换请求；第一核心网设备从接入网设备接收第二切换请求的响应消息；第一核心网设备向第二核心网设备发送第一切换请求的响应消息，第一切换请求的响应消息携带第三IP地址。本发明实施例有利于减少网络侧设备在终端切换过程中的信令交互，提升切换效率。

Description

一种切换方法及设备
本发明要求2016年9月30日递交的发明名称为“一种切换方法及设备”的申请号PCT/CN2016/101148的在先申请优先权，上述在先申请的内容以引入的方式并入本文本中。
技术领域
本发明涉及通信技术领域，尤其涉及一种切换方法及设备。
背景技术
第4代(4th Generation，4G)移动通信网络，例如长期演进(Long Term Evolution，LTE)网络，目前已经实现了广覆盖。4G网络因其通信速度快、网络频谱宽、通信灵活等特点，赢得了用户和运营商的一致好评。但物联网、车联网等网络需求的出现，用户对于下一代移动通信网络，即第5代(5th Generation，5G)移动通信网络的诉求越来越多，例如要求连续广域覆盖100兆字节/每秒(Mbps)的用户体验速率、热点1千兆字节/每秒(Gbps)的用户体验速率、1毫秒(ms)以内的空口时延、100ms以内的端到端时延、可靠性保障等等。
4G网络商用初期，实践中需要保障4G网络与第二代(2nd Generation，2G)移动通信网络或第三代(3rd Generation，3G)移动通信网络之间的互操作，以保证业务的连续性。而4G网络与2G网络或3G网络之间的互操作涉及诸多复杂流程，例如承载/隧道模型的映射、服务质量(Quality of Service，QoS)参数的映射、安全参数的映射、缺省承载、允许无缺省承载的交接等等。
类似的，在5G网络部署初期，也需要保障5G网络与4G网络或其他网络之间的互操作，然而现有技术中不同制式网络(例如4G网络与2G网络或3G网络)之间的互操作流程过于复杂，不利于保障5G网络的部署进程。
发明内容
本发明的实施例提供一种切换方法及设备，以期简化不同制式网络之间的互操作流程。
本发明实施例的第一方面，提供一种切换方法，包括：第一核心网设备从第二核心网设备接收第一切换请求，所述第一切换请求携带第一互联网协议IP地址，所述第一IP地址用于第一接入点名称APN的建立过程，其中，所述第一核心网设备应用于第一制式网络，所述第二核心网设备应用于第二制式网络，所述第一IP地址为所述第二制式网络为终端分配的IP地址；所述第一核心网设备为所述终端在所述第一制式网络中发起所述第一APN的建立过程；其中，所述第一核心网设备为所述终端在所述第一制式网络发起所述第一APN的建立过程，包括：所述第一核心网设备基于所述第一IP地址向第一网关发送第一创建会话请求；所述第一核心网设备从所述第一网关接收第一创建会话响应，所述第一创建会话响应携带所述第一制式网络为所述终端分配的第三地址，所述第一创建会话响应用于指示所述终端使用所述第三IP地址；所述第一核心网设备向接入网设备发送第二切换请求，其中，所述接入网设备应用于所述第一制式网络；所述第一核心网设备从所述接入网设备接收所述第二切换请求的响应消息；所述第一核心网设备向所述第二核心网设备发送所述第一切换请求的响应消息，所述第一切换请求的响应消息携带所述第三IP地址。
由上可见，第一制式网络的第一核心网设备接收到第二制式网络的第二核心网设备发送的第一切换请求后，根据第一IP地址为终端发起第一APN的建立过程，并向接入网设备发送第二切换请求，以及接收接入网设备发送的第二切换请求的响应消息，这之后，向第二核心网设备发送第一切换请求的响应消息。从而，终端可以从第二网络制式切换至第一网络制式。可见，本发明实施例提供的方案无需复杂的QoS映射、Bearer ID映射、位置标识等映射的流程，简化了不同制式网络之间的互操作流程，有利于在终端切换至不同制式网络过程中，减少网络侧设备的信令交互过程，提升切换效率。
在一个可能的设计中，所述第一切换请求还携带指示信息，所述指示信息用于指示所述第一核心网设备在完成所述第一APN的建立过程之后向所述 第二核心网设备发送第一通知消息，所述方法还包括：所述第一核心网设备向所述第二核心网设备发送所述第一通知消息，所述第一通知消息用于通知所述第二核心网设备：所述第一核心网设备基于所述第一IP地址为所述终端建立了所述第一APN，所述第一通知消息中携带所述第一IP地址和所述第三IP地址。
在一个可能的设计中，所述第一核心网设备向所述接入网设备发送第二切换请求之前，所述方法还包括：所述第一核心网设备从所述第一网关接收承载创建请求消息；所述第一核心网设备向所述第一网关发送承载创建响应消息。
在一个可能的设计中，所述第一核心网设备为所述终端在所述第一制式网络中发起所述第一APN的建立过程之后，所述方法还包括：所述第一核心网设备为所述终端在所述第一制式网络中发起第二APN的建立过程。
在一个可能的设计中，所述第一切换请求还携带第二IP地址，其中，所述第二IP地址为所述第二制式网络为所述终端分配的IP地址，所述第一核心网设备为所述终端在所述第一制式网络中发起第二APN的建立过程，包括：所述第一核心网设备向第一网关发送第二创建会话请求；所述第一核心网设备从所述第一网关接收第二创建会话响应，所述第二创建会话响应携带所述第一制式网络为所述终端分配的第四IP地址，所述第二创建会话响应用于指示所述终端使用所述第四IP地址。
在一个可能的设计中，所述第一切换请求的响应消息携带以下至少一项：附着接受消息，所述附着接受消息携带所述第一APN的信息、所述第一IP地址、所述第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址；分组数据网络PDN连接建立接受消息，所述PDN连接建立接受消息携带所述第二APN的信息；会话管理SM请求消息，所述SM请求消息携带所述终端在所述第一制式网络的承载信息。
在一个可能的设计中，所述第一核心网设备为所述终端的所述第一IP地址向第一网关发送第一创建会话请求之前，所述方法还包括：所述第一核心网 设备为所述终端向归属用户服务器发送位置更新请求消息；所述第一核心网设备从所述归属用户服务器接收位置更新确认消息。
在一个可能的设计中，所述第一核心网设备为所述终端在所述第一制式网络中发起第二接入点名称APN的建立过程之后，所述方法还包括：所述第一核心网设备向所述第二核心网设备发送第二通知消息，所述第二通知消息用于通知所述第二核心网设备：所述第一核心网设备为基于所述第二IP地址为所述终端建立了所述第二APN，所述第二通知消息中携带所述第二IP地址和所述第四IP地址。
在一个可能的设计中，所述PDN连接建立接受消息还携带所述第二IP地址、所述第四IP地址和第二使用信息，所述第二使用信息用于指示所述终端在第一制式网络使用所述第四IP地址代替所述第二IP地址。
在一个可能的设计中，所述第一切换请求还携带以下至少一项：所述终端的国际移动用户识别码IMSI、所述终端的安全上下文、所述终端的移动性管理上下文、所述终端的会话管理类上下文以及所述终端在所述第一制式网络的终端网络能力信息。
在一个可能的设计中，所述第一核心网设备向所述第二核心网设备发送第一切换请求的响应消息之后，所述方法还包括：所述第一核心网设备从所述第一网关接收承载创建请求消息；所述第一核心网设备从所述接入网设备接收切换到第一制式网络的完成消息；所述第一核心网设备向所述接入网设备发送承载建立请求消息；所述第一核心网设备从所述接入网设备接收承载建立响应消息；所述第一核心网设备向所述第一网关发送承载创建响应消息。
在一个可能的设计中，所述第一核心网设备从所述接入网设备接收切换到第一制式网络的完成消息之后，所述方法还包括：所述第一核心网设备向所述第二核心网设备发送切换完成通知消息；所述第一核心网设备从所述第二核心网设备接收切换完成确认消息。
本发明实施例的第二方面，还提供一种切换方法，包括：第二核心网设备从接入网设备接收切换要求消息，其中，所述第二核心网设备和所述接入网设备应用于第二制式网络；所述第二核心网设备向第一核心网设备发送第一切 换请求，所述第一切换请求携带第一互联网协议IP地址，所述第一IP地址用于终端在第一制式网络的第一接入点名称APN的建立过程，其中，所述第一核心网设备应用于所述第一制式网络，所述第一IP地址为所述第二制式网络为所述终端分配的IP地址；所述第二核心网设备从所述第一核心网设备接收所述第一切换请求的响应消息，所述第一切换请求的响应消息携带第三IP地址，所述第三IP地址为所述第一制式网络在所述第一APN的建立过程中为所述终端分配的IP地址；所述第二核心网设备向所述接入网设备发送切换要求响应消息。
由上可见，第二制式网络的第二核心网设备接收第二制式网络的接入网设备发送的切换要求消息，第二核心网设备向第一制式网络的第一核心网设备发送第一切换请求，第一切换请求携带第一互联网协议IP地址，第一IP地址用于终端在第一制式网络的第一APN的建立过程，第一APN建立过程完成后，第二核心网设备接收第一核心网设备发送的第一切换请求的响应消息，并向接入网设备发送切换要求响应消息。可见，本发明实施例的方案无需复杂的QoS映射、Bearer ID映射、位置标识等映射的流程，简化了不同制式网络之间的互操作流程，有利于在终端切换至不同制式网络过程中，减少网络侧设备的信令交互过程，提升切换效率。
在一个可能的设计中，所述第一切换请求还携带指示信息，所述指示信息用于指示所述第一核心网设备在完成所述第一APN的建立过程之后向所述第二核心网设备发送第一通知消息，所述方法还包括：所述第二核心网设备从所述第一核心网设备接收所述第一通知消息，所述第一通知消息用于通知所述第二核心网设备：所述第一核心网设备基于所述第一IP地址为所述终端建立了所述第一APN，所述第一通知消息中携带所述第一IP地址和所述第一制式网络在所述第一APN的建立过程中为所述终端分配的第三IP地址。
在一个可能的设计中，所述第二核心网设备从所述第一核心网设备接收所述第一通知消息之后，所述方法还包括：所述第二核心网设备向第二策略设备发送第三通知消息，所述第三通知消息用于通知所述第二策略设备：所述第一核心网设备基于所述第一IP地址为所述终端建立了所述第一APN，其中， 所述第二策略设备应用于所述第二制式网络，所述第三通知消息中携带所述第三IP地址。
在一个可能的设计中，所述第一切换请求还携带第二IP地址，所述第二IP地址用于所述终端在所述第一制式网络的第二APN的建立过程，其中，所述第二IP地址为所述第二制式网络为所述终端分配的IP地址。
在一个可能的设计中，所述第一切换请求的响应消息携带以下至少一项：附着接受消息，所述附着接受消息携带所述第一APN的信息、所述第一IP地址、所述第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址；分组数据网络PDN连接建立接受消息，所述PDN连接建立接受消息携带所述第二APN的信息；会话管理SM请求消息，所述SM请求消息携带所述终端在所述第一制式网络的承载信息。
在一个可能的设计中，所述PDN连接建立接受消息还携带所述第二IP地址、所述第四IP地址和第二使用信息，所述第二使用信息用于指示所述终端在第一制式网络使用所述第四IP地址代替所述第二IP地址。
在一个可能的设计中，所述切换要求响应消息携带以下至少一项：所述附着接受消息，所述PDN连接建立接受消息，或者，所述SM请求消息。
在一个可能的设计中，所述第二核心网设备向第一核心网设备发送第一切换请求之后，所述方法还包括：所述第二核心网设备从所述第一核心网设备接收第二通知消息，所述第二通知消息用于通知所述第二核心网设备：所述第一核心网设备基于所述第二IP地址为所述终端建立了所述第二APN，所述第二通知消息中携带所述第二IP地址和在所述第二APN的建立过程中为所述终端分配的所述第四IP地址。
在一个可能的设计中，所述第二核心网设备从所述第一核心网设备接收第二通知消息之后，所述方法还包括：所述第二核心网设备向第二策略设备发送第三通知消息，所述第三通知消息用于通知所述第二策略设备：所述第一核心网设备基于所述第一IP地址为所述终端建立了所述第一APN，其中，所述第二策略设备应用于所述第二制式网络，所述第三通知消息中携带所述第三 IP地址；或者，所述第二核心网设备向第二策略设备发送第四通知消息，所述第四通知消息用于通知所述第二策略设备：所述第一核心网设备基于所述第二IP地址为所述终端建立了所述第二APN，所述第二策略设备应用于所述第二制式网络，所述第四通知消息中携带所述第四IP地址。
在一个可能的设计中，所述第二核心网设备向第一核心网设备发送第一切换请求之前，所述方法还包括：所述第二核心网设备从所述终端接收附着请求消息，所述附着请求消息携带所述终端在所述第一制式网络中的终端网络能力信息。
在一个可能的设计中，所述第二核心网设备向第一核心网设备发送第一切换请求之前，所述方法还包括：所述第二核心网设备向所述终端发送查询请求消息；所述第二核心网设备从所述终端接收查询请求响应消息，所述查询请求响应消息携带所述终端在所述第一制式网络中的终端网络能力信息。
在一个可能的设计中，所述第一切换请求还携带以下至少一项：所述终端的国际移动用户识别码IMSI、所述终端的安全上下文、所述终端的移动性管理上下文、所述终端的会话管理类上下文以及所述终端在第一制式网络的终端网络能力信息。
在一个可能的设计中，所述第二核心网设备从所述第一核心网设备接收第一切换请求的响应消息之后，所述方法还包括：所述第二核心网设备向所述第二策略设备发送第七通知消息，所述第七通知消息用于通知所述第二策略设备：所述终端从所述第二制式网络切换到所述第一制式网络。
在一个可能的设计中，所述第七通知消息携带所述第一IP地址、所述第三IP地址和第三使用信息，所述第三使用信息用于指示应用功能设备在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，其中所述应用功能设备应用于所述第一制式网络和所述第二制式网络。
在一个可能的设计中，所述第七通知消息还携带第二IP地址、第四IP地址和第四使用信息，所述第四使用信息用于指示应用功能设备在所述第一制式网络中使用所述第四IP地址替代所述第二IP地址。
在一个可能的设计中，所述第二核心网设备从所述第一核心网设备接收 第一切换请求的响应消息之后，所述方法还包括：所述第二核心网设备向所述第一核心网设备发送切换完成确认消息；所述第二核心网设备向所述第二策略设备发送第九通知消息，所述第九通知消息用于通知所述第二策略设备：所述终端从所述第二制式网络切换到所述第一制式网络。
在一个可能的设计中，所述第九通知消息携带所述第一IP地址、所述第三IP地址和第三使用信息，所述第三使用信息用于指示应用功能设备在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，其中所述应用功能设备应用于所述第一制式网络和所述第二制式网络。
在一个可能的设计中，所述第九通知消息还携带第二IP地址、第四IP地址和第四使用信息，所述第四使用信息用于指示应用功能设备在所述第一制式网络中使用所述第四IP地址替代所述第二IP地址。
本发明实施例的第三方面，还提供一种切换方法，包括：第二接入网设备向第二核心网设备发送切换要求消息，所述切换要求消息用于请求将终端从第二制式网络切换到第一制式网络，其中，所述第二接入网设备和所述第二核心网设备应用于所述第二制式网络；所述第二接入网设备从所述第二核心网设备接收切换要求响应消息，所述切换要求响应消息携带以下至少一项：附着接受消息、分组数据网络PDN连接建立接受消息或会话管理SM请求消息，其中，所述附着接受消息携带第一核心网设备为所述终端在所述第一制式网络建立的第一接入点名称APN的信息、所述第二制式网络为所述终端分配的第一互联网协议IP地址、所述第一制式网络在所述第一APN的建立过程中为所述终端分配的第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，所述PDN连接建立接受消息携带所述第一核心网设备为所述终端在所述第一制式网络建立的第二APN的信息，所述SM请求消息携带所述终端在所述第一制式网络的承载信息；所述第二接入网设备向所述终端发送切换命令消息，所述切换命令消息携带以下至少一项：所述附着接受消息、所述PDN连接建立接受消息或所述SM请求消息。
由上可见，第二制式网络的第二接入网设备向第二制式网络的第二核心 网设备发送切换要求消息，切换要求消息用于请求将终端从第二制式网络切换到第一制式网络，接着，第二接入网设备从第二核心网设备接收切换要求响应消息，第二接入网设备向终端发送切换命令消息，指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址。可见，本发明实施例的方案无需复杂的QoS映射、Bearer ID映射、位置标识等映射的流程，简化了不同制式网络之间的互操作流程，有利于在终端切换至不同制式网络过程中，减少网络侧设备的信令交互过程，提升切换效率。
在一个可能的设计中，所述PDN连接建立接受消息还携带所述第二制式网络为所述终端分配的第二IP地址、所述所述第二APN的建立过程中所述第一制式网络为所述终端分配的第四IP地址和第二使用信息，所述第二使用信息用于指示所述终端在第一制式网络使用所述第四IP地址替代所述第二IP地址。
本发明实施例的第四方面，还提供一种切换方法，包括：终端从第二接入网设备接收切换命令消息，所述切换命令消息携带以下至少一项：附着接受消息、分组数据网络PDN连接建立接受消息或会话管理SM请求消息，其中，所述附着接受消息携带第一核心网设备为所述终端在所述第一制式网络建立的第一接入点名称APN的信息、所述第二制式网络为所述终端分配的第一互联网协议IP地址、所述第一制式网络在所述第一APN的建立过程中为所述终端分配的第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，所述PDN连接建立接受消息携带所述第一核心网设备为所述终端在所述第一制式网络建立的第二APN的信息，所述SM请求消息携带所述终端在所述第一制式网络的承载信息；其中，所述第二接入网设备应用于所述第二制式网络；所述终端根据所述附着接受消息、所述PDN连接建立接受消息或所述SM请求消息中的至少一项接入所述第一制式网络；所述终端向第一接入网设备发送切换完成消息，所述第一接入网设备应用于所述第一制式网络。
由上可见，终端从第二制式网络的第二接入网设备接收切换命令消息，该切换命令消息携带以下至少一项：附着接受消息、分组数据网络PDN连接 建立接受消息或会话管理SM请求消息，其次，终端根据附着接受消息、PDN连接建立接受消息或SM请求消息中的至少一项接入第一制式网络，最后向第一制式网络中的第一接入网设备发送切换完成消息，从而实现从第二制式网络切换至第一制式网络。可见，本发明实施例的方案无需复杂的QoS映射、Bearer ID映射、位置标识等映射的流程，简化了不同制式网络之间的互操作流程，有利于在终端切换至不同制式网络过程中，减少网络侧设备的信令交互过程，提升切换效率。
在一个可能的设计中，所述PDN连接建立接受消息还携带所述第二制式网络为所述终端分配的第二IP地址、所述第二APN的建立过程中所述第一制式网络为所述终端分配的第四IP地址和第二使用信息，所述第二使用信息用于指示所述终端在第一制式网络使用所述第四IP地址替代所述第二IP地址。
在一个可能的设计中，所述终端在接收到所述切换命令消息之后，所述方法还包括：所述终端不使用第五IP地址，所述第五IP地址是所述第二制式网络在所述终端接收来自所述第一接入网设备的切换命令消息之前为所述终端分配的IP地址。
在一个可能的设计中，所述终端从第二接入网设备接收切换命令消息之前，所述方法还包括：所述终端向第二核心网设备发送附着请求消息，所述附着请求消息用于请求附着到第一制式网络，其中，所述附着请求消息携带所述终端在所述第一制式网络的终端网络能力信息，所述第二核心网设备应用于所述第二制式网络。
在一个可能的设计中，所述终端从第二接入网设备接收切换命令消息之前，所述方法还包括：所述终端从第二核心网设备接收查询请求消息，其中，所述第二核心网设备应用于所述第二制式网络；所述终端向所述第二核心网设备发送查询请求响应消息，所述查询请求响应消息携带所述终端在所述第一制式网络的终端网络能力信息。
在一个可能的设计中，所述终端向所述第一接入网设备发送切换完成消息之后，所述方法还包括：
所述终端在所述第一制式网络为所述终端建立第二承载。
在一个可能的设计中，所述终端向所述第一接入网设备发送切换完成消息之后，所述方法还包括：
所述终端向应用功能设备发送第十一通知消息，所述第十一通知消息用于通知所述应用功能设备：所述终端从所述第二制式网络切换到所述第一制式网络，其中，所述应用功能设备应用于所述第一制式网络和第二制式网络。
在一个可能的设计中，所述第十一通知消息携带所述第一IP地址、所述第三IP地址和第三使用信息，所述第三使用信息用于指示应用功能设备在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，其中所述应用功能设备应用于所述第一制式网络和所述第二制式网络。
在一个可能的设计中，所述十一通知消息还携带所述第二IP地址、所述第四IP地址和第四使用信息，所述第四使用信息用于指示所述应用功能设备在所述第一制式网络中使用所述第四IP地址替代所述第二IP地址。
本发明实施例的第五方面，还提供一种承载建立方法，包括：应用功能设备向为终端向第二策略设备发送业务建立请求消息，所述业务建立请求消息携带业务要求信息，以使得所述第二策略设备在第二制式网络为所述终端的业务建立第一承载，其中，所述应用功能设备应用于第一制式网络和所述第二制式网络，所述第二策略设备应用于所述第二制式网络；所述应用功能设备从所述第二策略设备接收第五通知消息，所述第五通知消息用于通知所述应用功能设备：所述第一核心网设备基于第一互联网协议IP地址为所述终端在所述第一制式网络中建立了第一接入点名称APN，第五通知消息携带在所述第一APN的建立过程中为所述终端分配的第三IP地址，和/或，所述应用功能设备从所述第二策略设备接收第六通知消息，所述第六通知消息用于通知所述应用功能设备：所述第一核心网设备基于第二IP地址为所述终端在所述第一制式网络中建立了第二APN，所述第六通知消息携带在所述第二APN的建立过程中为所述终端分配的第四IP地址，所述第一IP地址和所述第二IP地址为所述第二制式网络为所述终端分配的IP地址；所述应用功能设备为所述终端的所述业务在所述第一制式网络发起第二承载的建立过程。
在一个可能的设计中，所述应用功能设备为所述终端的所述业务在所述 第一制式网络发起第二承载的创建过程之前，所述方法还包括，所述应用功能设备向接入转发网关发送更新用户面请求消息，用于请求所述接入转发网关将所述第一IP地址更新为所述第三IP地址，或者，用于请求所述接入转发网关将所述第二IP地址更新为所述第四IP地址；所述应用功能设备从所述接入转发网关接收更新用户面请求响应消息。
在一个可能的设计中，所述应用功能设备为所述终端在所述第一制式网络发起第二承载的创建过程之前，所述方法还包括，所述应用功能设备使用所述第三IP地址或所述第四IP地址与所述终端进行信令面通信。
在一个可能的设计中，所述应用功能设备为所述终端在所述第一制式网络发起第二承载的创建过程，包括：所述应用功能设备根据所述第一IP地址或所述第二IP地址查找所述业务要求信息；所述应用功能设备根据所述业务要求信息为所述终端在所述第一制式网络发起所述第二承载的建立过程。
在一个可能的设计中，所述方法还包括：所述应用功能设备向第一策略设备发送认证授权请求消息，其中，所述第一策略设备应用于所述第一制式网络；所述应用功能设备从所述第一策略设备接收认证授权应答消息。
在一个可能的设计中，所述应用功能设备向第一策略设备发送认证授权请求消息之前，所述方法还包括，所述应用功能设备根据所述第一IP地址或所述第二IP地址寻址到所述第一策略设备。
本发明实施例的第六方面，还提供一种承载建立方法，包括：第二策略设备从应用功能设备接收业务建立请求消息，所述业务建立请求消息携带业务要求信息，其中，所述第二策略设备应用于第二制式网络，所述应用功能设备应用于第一制式网络和所述第二制式网络；所述第二策略设备根据所述业务要求信息在所述第二制式网络为终端的业务建立第一承载。
在一个可能的设计中，所述方法还包括：所述第二策略设备从第二核心网设备接收第三通知消息，所述第三通知消息用于通知所述第二策略设备：第一核心网设备基于第一互联网协议IP地址为所述终端在所述第一制式网络中建立了第一接入点名称APN，所述第三通知消息中携带在所述第一APN的建立过程中为所述终端分配的第三IP地址，和/或，所述第二策略设备从第二核 心网设备接收第四通知消息，所述第四通知消息用于通知所述第二策略设备：所述第一核心网设备基于第二IP地址为所述终端在所述第二制式网络中建立了第二APN，所述第四通知消息中携带在所述第二APN的建立过程中为所述终端分配的第四IP地址，所述第一核心网设备应用于所述第一制式网络，所述第二核心网设备应用于所述第二制式网络，所述第一IP地址和所述第二IP地址为所述第二制式网络为所述终端分配的IP地址；所述第二策略设备在所述第一制式网络为所述终端的所述业务建立第二承载。
在一个可能的设计中，第二策略设备从第二核心网设备接收第三通知消息和/或第四通知消息之后，所述方法还包括：所述第二策略设备向所述应用功能设备发送第五通知消息，所述第五通知消息用于通知所述应用功能设备所述第一核心网设备基于所述第一IP地址为所述终端在所述第一制式网络中建立了所述第一APN，第五通知消息携带所述第三IP地址，和/或，所述第二策略设备向所述应用功能设备发送第六通知消息，所述第六通知消息用于通知所述第一核心网设备基于所述第二IP地址为所述终端在所述第一制式网络中建立了所述第二APN，第五通知消息携带所述第四IP地址。
在一个可能的设计中，所述第二策略设备在所述第一制式网络为所述终端的所述业务建立第二承载，包括：所述第二策略设备根据所述第一IP地址或所述第二IP地址查找所述业务要求信息；所述第二策略设备根据所述业务要求信息为所述终端在所述第一制式网络建立所述第二承载。
在一个可能的设计中，所述方法还包括：所述第二策略设备向第二网关发送信用重授权请求消息；所述第二策略设备从所述第二网关接收信用重授权应答消息。
在一个可能的设计中，所述第二策略设备向第二网关发送信用重授权请求消息之前，所述方法还包括：所述第二策略设备根据所述第一IP地址或所述第二IP地址寻址到所述第二网关。
在一个可能的设计中，所述方法还包括：所述第二策略设备从第二核心网设备接收第七通知消息或第九通知消息，所述第七通知消息或第九通知消息用于通知所述第二策略设备：所述终端从所述第二制式网络切换到所述第一制 式网络，其中，所述第二核心网设备应用于所述第二制式网络。
在一个可能的设计中，所述第七通知消息或第九通知消息携带所述第一IP地址、所述第三IP地址和第三使用信息，所述第三使用信息用于指示应用功能设备在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，其中所述应用功能设备应用于所述第一制式网络和所述第二制式网络。
在一个可能的设计中，所述第七通知消息或第九通知消息还携带所述第二IP地址、所述第四IP地址和第四使用信息，所述第四使用信息用于指示所述应用功能设备在所述第一制式网络中使用所述第四IP地址替代所述第二IP地址。
在一个可能的设计中，所述第二策略设备从第二核心网设备接收第七通知消息或第九通知消息之后，所述方法还包括：所述第二策略设备根据所述业务要求信息为所述终端在所述第一制式网络建立所述第二承载。
在一个可能的设计中，所述第二策略设备从第二核心网设备接收第七通知消息或第九通知消息之后，所述方法还包括：所述第二策略设备向所述应用功能设备发送第八通知消息，所述第八通知消息用于通知所述应用功能设备：所述终端从所述第二制式网络切换到所述第一制式网络。
在一个可能的设计中，所述第八通知消息携带所述第一IP地址、所述第三IP地址和第三使用信息，所述第三使用信息用于指示应用功能设备在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，其中所述应用功能设备应用于所述第一制式网络和所述第二制式网络。
在一个可能的设计中，所述第八通知消息还携带所述第二IP地址、所述第四IP地址和第四使用信息，所述第四使用信息用于指示所述应用功能设备在所述第一制式网络中使用所述第四IP地址替代所述第二IP地址。
本发明实施例的第七方面，提供一种第一核心网设备，该第一核心网设备具有实现上述方法设计中第一核心网设备的行为的功能。所述功能可以通过硬件实现，也可以通过硬件执行相应的软件实现。所述硬件或软件包括一个或多个与上述功能相对应的模块。
在一个可能的设计中，第一核心网设备包括处理器，所述处理器被配置 为支持第一核心网设备执行上述方法中相应的功能。进一步的，第一核心网设备还可以包括通信接口，所述通信接口用于支持第一核心网设备与其他网元之间的通信。进一步的，第一核心网设备还可以包括存储器，所述存储器用于与处理器耦合，其保存第一核心网设备必要的程序指令和数据。
本发明实施例的第八方面，提供一种第二核心网设备，该第二核心网设备具有实现上述方法设计中第二核心网设备的行为的功能。所述功能可以通过硬件实现，也可以通过硬件执行相应的软件实现。所述硬件或软件包括一个或多个与上述功能相对应的模块。
在一个可能的设计中，第二核心网设备包括处理器，所述处理器被配置为支持第二核心网设备执行上述方法中相应的功能。进一步的，第二核心网设备还可以包括通信接口，所述通信接口用于支持第二核心网设备与其他网元之间的通信。进一步的，第二核心网设备还可以包括存储器，所述存储器用于与处理器耦合，其保存第二核心网设备必要的程序指令和数据。
本发明实施例的第九方面，提供一种终端，该终端具有实现上述方法设计中终端的行为的功能。所述功能可以通过硬件实现，也可以通过硬件执行相应的软件实现。所述硬件或软件包括一个或多个与上述功能相对应的模块。
在一个可能的设计中，终端包括处理器，所述处理器被配置为支持终端执行上述方法中相应的功能。进一步的，终端还可以包括收发器，所述收发器用于支持终端与网元之间的通信。进一步的，终端还可以包括存储器，所述存储器用于与处理器耦合，其保存终端必要的程序指令和数据。
本发明实施例的第十方面，提供一种第一策略设备，该第一策略设备具有实现上述方法设计中第一策略设备的行为的功能。所述功能可以通过硬件实现，也可以通过硬件执行相应的软件实现。所述硬件或软件包括一个或多个与上述功能相对应的模块。
本发明实施例的第十一方面，提供一种应用功能设备，该应用功能设备具有实现上述方法设计中应用功能设备的行为的功能。所述功能可以通过硬件实现，也可以通过硬件执行相应的软件实现。所述硬件或软件包括一个或多个与上述功能相对应的模块。
本发明实施例的第十二方面，提供一种第二策略设备，该第二策略设备具有实现上述方法设计中第二策略设备的行为的功能。所述功能可以通过硬件实现，也可以通过硬件执行相应的软件实现。所述硬件或软件包括一个或多个与上述功能相对应的模块。
本发明实施例的第十三方面，还提供一种承载建立方法，包括：
应用功能设备向第二策略设备发送业务建立请求消息，所述业务建立请求消息携带业务要求信息，以使得所述第二策略设备在第二制式网络为终端建立第一承载，其中，所述应用功能设备应用于第一制式网络和所述第二制式网络，所述第二策略设备应用于所述第二制式网络；所述应用功能设备从所述第二策略设备接收第八通知消息，所述第八通知消息用于通知所述应用功能设备：所述终端从所述第二制式网络切换到所述第一制式网络；所述应用功能设备为所述终端在所述第一制式网络发起第二承载的建立过程。
在一个可能的设计中，所述第八通知消息携带所述第一IP地址、所述第三IP地址和第三使用信息，所述第三使用信息用于指示应用功能设备在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，其中所述应用功能设备应用于所述第一制式网络和所述第二制式网络。
在一个可能的设计中，所述八通知消息还可以携带所述第二IP地址、所述第四IP地址和第四使用信息，所述第四使用信息用于指示所述应用功能设备在所述第一制式网络中使用所述第四IP地址替代所述第二IP地址。
本发明实施例的第十四方面，还提供一种承载建立方法，包括：
应用功能设备向第二策略设备发送业务建立请求消息，所述业务建立请求消息携带业务要求信息，以使得所述第二策略设备在第二制式网络为终端建立第一承载，其中，所述应用功能设备应用于第一制式网络和所述第二制式网络，所述第二策略设备应用于所述第二制式网络；所述应用功能设备从所述第二策略设备接收第十一通知消息，所述第十一通知消息用于通知所述应用功能设备：所述终端从所述第二制式网络切换到所述第一制式网络；所述应用功能设备为所述终端在所述第一制式网络发起第二承载的建立过程。
在一个可能的设计中，所述第十一通知消息携带所述第一IP地址、所述 第三IP地址和第三使用信息，所述第三使用信息用于指示应用功能设备在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，其中所述应用功能设备应用于所述第一制式网络和所述第二制式网络。
在一个可能的设计中，所述十一通知消息还可以携带所述第二IP地址、所述第四IP地址和第四使用信息，所述第四使用信息用于指示所述应用功能设备在所述第一制式网络中使用所述第四IP地址替代所述第二IP地址。
本发明实施例的第十五方面，还提供一种切换方法，包括：
第二核心网设备从接入网设备接收切换要求消息，其中，所述第二核心网设备和所述接入网设备应用于第二制式网络；所述第二核心网设备向第一核心网设备发送第一切换请求，所述第一切换请求携带第二核心网设备的地址；所述第二核心网设备从所述第一核心网设备接收第一切换请求的响应消息；所述第二核心网设备向所述第二策略设备发送第七通知消息，所述第七通知消息用于通知所述第二策略设备：所述终端从所述第二制式网络切换到所述第一制式网络，所述第二策略设备应用于第二制式网络。
在一个可能的设计中，所述第七通知消息携带所述第一IP地址、所述第三IP地址和第三使用信息，所述第三使用信息用于指示应用功能设备在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，其中所述应用功能设备应用于所述第一制式网络和所述第二制式网络；
在一个可能的设计中，所述第七通知消息还携带第二IP地址、第四IP地址和第四使用信息，所述第四使用信息用于指示所述应用功能设备在所述第一制式网络中使用所述第四IP地址替代所述第二IP地址。
本发明实施例的第十六方面，还提供一种切换方法，包括：
第二核心网设备从接入网设备接收切换要求消息，其中，所述第二核心网设备和所述接入网设备应用于第二制式网络；所述第二核心网设备向第一核心网设备发送第一切换请求，所述第一切换请求携带第二核心网设备的地址；所述第二核心网设备从所述第一核心网设备接收第一切换请求的响应消息；所述第二核心网设备从所述第一核心网设备接收第一切换请求的响应消息；所述第二核心网设备从所述第一核心网络设备接收切换完成通知消息；所述第二核 心网设备向所述第一核心网设备发送切换完成确认消息；所述第二核心网设备向所述第二策略设备发送第九通知消息，所述第九通知消息用于通知所述第二策略设备：所述终端从所述第二制式网络切换到所述第一制式网络。
在一个可能的设计中，所述第九通知消息携带所述第一IP地址、所述第三IP地址和第三使用信息，所述第三使用信息用于指示应用功能设备在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，其中所述应用功能设备应用于所述第一制式网络和所述第二制式网络；
在一个可能的设计中，所述第九通知消息还携带第二IP地址、第四IP地址和第四使用信息，所述第四使用信息用于指示所述应用功能设备在所述第一制式网络中使用所述第四IP地址替代所述第二IP地址。
本发明实施例的第十七方面，还提供一种切换方法，包括：
第一核心网设备从第二核心网设备接收第一切换请求，所述第一切换请求携带第二核心网设备的地址，所述第一核心网设备应用于第一制式网络，所述第二核心网设备应用于第二制式网络；所述第一核心网设备向所述第二核心网设备发送第一切换请求的响应消息；所述第一核心网络设备向所述第二核心网络设备发送切换完成通知消息；所述第一核心网设备从所述第一核心网设备接收切换完成确认消息。
在一个可能的设计中，第一核心网设备从第二核心网设备接收第一切换请求之后，所述方法还包括：第一核心网设备为终端在所述第一制式网络中发起所述第一APN的建立过程。
在一个可能的设计中，所述第二核心网设备与第二网关合一部署，所述第一切换请求携带的第二核心网设备的地址用于在所述第一APN的建立过程中寻址所述第二核心网设备。
在一个可能的设计中，所述第一核心网设备向所述第二核心网设备发送的第一切换请求的响应消息中携带附着接受消息，其中，所述附着接受消息携带第一核心网设备为终端在第一制式网络建立的第一接入点名称APN的信息。
相较于现有技术，第一制式网络的第一核心网设备接收到第二制式网络的 第二核心网设备发送的第一切换请求后，根据第一IP地址和第三核心网设备的地址，为终端发起第一APN的建立过程，并向接入网设备发送第二切换请求，以及接收接入网设备发送的第二切换请求的响应消息，这之后，向第二核心网设备发送第一切换请求的响应消息。从而，终端可以从第二网络制式切换至第一网络制式。可见，本发明实施例提供的方案无需复杂的QoS映射、Bearer ID映射、位置标识等映射的流程，简化了不同制式网络之间的互操作流程，有利于在终端切换至不同制式网络过程中，减少网络侧设备的信令交互过程，提升切换效率。
附图说明
为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例或现有技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动性的前提下，还可以根据这些附图获得其他的附图。
图1为本发明实施例提供的一种可能的网络架构的示意图；
图2为本发明实施例提供的一种切换方法的通信示意图；
图3为本发明实施例提供的另一种切换方法的通信示意图；
图3a为本发明实施例提供的另一种切换方法的通信示意图；
图3b为本发明实施例提供的另一种切换方法的通信示意图；
图3c为本发明实施例提供的另一种切换方法的通信示意图；
图3d为本发明实施例提供的另一种切换方法的通信示意图；
图4为本发明实施例提供的一种承载建立方法的通信示意图；
图4a为本发明实施例提供的另一种承载建立方法的通信示意图；
图5为本发明实施例提供的又一种切换方法的通信示意图；
图5a为本发明实施例提供的又一种切换方法的通信示意图；
图5b为本发明实施例提供的又一种切换方法的通信示意图；
图6为本发明实施例提供的另一种承载建立方法的通信示意图；
图6a为本发明实施例提供的另一种承载建立方法的通信示意图；
图6b为本发明实施例提供的另一种承载建立方法的通信示意图；
图7为本发明实施例提供的一种接入点名称的建立过程的通信示意图；
图8为本发明实施例提供的另一种接入点名称的建立过程的通信示意图；
图9A为本发明实施例提供的一种第一核心网设备的结构示意图；
图9B为本发明实施例提供的另一种第一核心网设备的结构示意图；
图10A为本发明实施例提供的一种第二核心网设备的结构示意图；
图10B为本发明实施例提供的另一种第二核心网设备的结构示意图；
图11A为本发明实施例提供的一种第二接入网设备的结构示意图；
图11B为本发明实施例提供的另一种第二接入网设备的结构示意图；
图12A为本发明实施例提供的一种终端的结构示意图；
图12B为本发明实施例提供的另一种终端的结构示意图。
具体实施方式
为使本发明实施例的目的、技术方案和优点更加清楚，下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行描述。
本发明实施例描述的网络架构以及业务场景是为了更加清楚的说明本发明实施例的技术方案，并不构成对于本发明实施例提供的技术方案的限定，本领域普通技术人员可知，随着网络架构的演变和新业务场景的出现，本发明实施例提供的技术方案对于类似的技术问题，同样适用。
下面首先结合图1对本发明实施例适用的一些可能的应用场景及网络架构进行介绍。
图1示出了本发明实施例提供的一种可能的网络架构。该网络架构包括4G网络、5G网络和IP多媒体子系统(IP Multimedia Subsystem，IMS)网络。
其中，终端与4G网络中的演进型基站(eNB，Evolved NodeB)之间可以通过无线链路通信连接。该4G网络的网络侧设备主要包括移动性管理实体(MME，Mobility Management Entity)、服务网关(SGW，Serving Gateway)、策略和计费规则功能(PCRF，Policy and Charging Rules Function)实体和分组数据网络网关(PDN Gateway，PGW)、归属用户服务器(Home Subscriber  Server，HSS)等。
当终端接入5G网络时，终端与下一代无线接入网(Next Generation Radio Access Network，NG RAN)设备之间可以通过无线链路通信连接。该5G网络的网络侧设备主要包括控制面功能(Control Plane Function，CP Function)实体以及用户面控制功能(User Plane Function，UP Function)实体。
IMS网络包括代理呼叫会话控制功能(Proxy-Call Session Control Function，P-CSCF)实体、接入转发控制功能(Access Transfer Control Function，ATCF)实体以及接入转发网关(Access Transfer GateWay，ATGW)实体，另外，应用功能(Application Function，AF)设备是提供需要对传输平面资源进行策略、计费控制的应用层实体，对应于IMS网络中的P-CSCF实体和ATCF实体。
本发明实施例中，名词“网络”和“系统”经常交替使用，但本领域技术人员可以理解其含义。本发明实施例所涉及到的终端可以包括各种具有无限通信功能的手持设备、车载设备、可穿戴设备、计算设备或连接到无线调制解调器的其他处理设备，以及各种形式的用户设备(User Equipment，UE)，移动台(Mobile Station，MS)，终端设备(terminal device)等等。为方便描述，上面提到的设备统称为终端。
下面将基于上面所述的本发明实施例涉及的共性方面，对本发明实施例进一步详细说明。
现有方案中，不同制式网络之间的互操作流程过于复杂，不利于保障5G网络的部署进程。
有鉴于此，本发明实施例提供一种切换方法，和基于这个方法的第一核心网设备、第二核心网设备、终端和第二接入网设备等。该方法包括：第二核心网设备从第二接入网设备接收切换要求消息，其中，第二核心网设备和第二接入网设备应用于第二制式网络；第二核心网设备向第一核心网设备发送第一切换请求，第一切换请求携带第一IP地址，第一IP地址用于终端在第一制式网络的第一APN的建立过程，其中，第一核心网设备应用于第一制式网络，第一IP地址为第二制式网络为终端分配的IP地址；第一核心网设备为终端在 第一制式网络中发起第一APN的建立过程，其中，第一核心网设备为终端在第一制式网络中发起第一APN的建立过程，包括：第一核心网设备基于第一IP地址向第一网关发送第一创建会话请求，第一核心网设备从第一网关接收第一创建会话响应，第一创建会话响应携带第一制式网络为终端分配的第三IP地址，第一创建会话响应用于指示终端使用第三IP地址；第一核心网设备向第一接入网设备发送第二切换请求，其中，第一接入网设备应用于第一制式网络；第一核心网设备从第一接入网设备接收第二切换请求的响应消息；第一核心网设备向第二核心网设备发送第一切换请求的响应消息，该第一切换请求的响应消息携带第三IP地址；第二核心网设备向第二接入网设备发送切换要求响应消息；第二接入网设备向终端发送切换命令消息；终端接入第一制式网络；终端向第一接入网设备发送切换完成消息。由上可见，本发明实施例中，第一制式网络与第二制式网络之间的互操作流程简单，不需要进行包括各种参数映射在内的复杂流程。
上述方法中，切换要求响应消息可以携带附着接受消息、PDN连接建立接受消息或SM请求消息中的至少一项；切换命令消息也可以携带该附着接受消息、该PDN连接建立接受消息或该SM请求消息中的至少一项；终端可以根据该附着接受消息、该PDN连接建立接受消息或该SM请求消息中的至少一项接入第一制式网络。
本发明实施例提供的方案中，第一制式网络可以是4G网络、3G网络或2G网络，第二制式网络可以是5G网络；或者，第一制式网络可以是5G网络，第二制式网络可以是4G网络、3G网络或2G网络。当然，本发明实施例的方案还可以应用于其它场景，本发明实施例并不限定。
下面结合附图2，对本发明实施例提供的切换方法进行说明。图2示出了本发明实施例提供的一种切换方法。该方法包括：201～212部分，具体如下：
在201部分，第二接入网设备向第二核心网设备发送切换要求消息。
对应的，第二核心网设备从第二接入网设备接收切换要求消息。
其中，切换要求消息用于请求将终端从第二制式网络切换到第一制式网络，其中，第二接入网设备和第二核心网设备应用于第二制式网络。
在202部分，第二核心网设备向第一核心网设备发送第一切换请求。
对应的，第一核心网设备从第二核心网设备接收第一切换请求。
其中，第一切换请求携带第一IP地址，第一IP地址用于终端在第一制式网络的第一接入点名称(Access Point Name，APN)的建立过程。第一核心网设备应用于第一制式网络，第一IP地址为第二制式网络为终端分配的IP地址，例如可以是第二核心网设备为终端分配的IP地址。
在一个示例中，第一切换请求还携带指示信息，指示信息用于指示第一核心网设备在完成第一APN的建立过程之后向第二核心网设备第一通知消息。
在一个示例中，第一切换请求还携带第二IP地址，第二IP地址用于终端在第一制式网络的第二APN的建立过程，其中，第二IP地址为第二制式网络为终端分配的IP地址。
在一个示例中，第二核心网设备向第一核心网设备发送第一切换请求之前，第二核心网设备还可以从终端接收附着请求消息，附着请求消息携带终端在所述第一制式网络中的终端网络能力信息。
在一个示例中，第二核心网设备向第一核心网设备发送第一切换请求之前，第二核心网设备还可以向终端发送查询请求消息；并从终端接收查询请求响应消息，查询请求响应消息携带终端在第一制式网络中的终端网络能力信息。
在一个示例中，第一切换请求还携带以下至少一项：终端的国际移动用户识别码IMSI、终端的安全上下文、终端的移动性管理上下文、终端的会话管理类上下文以及终端在第一制式网络的终端网络能力信息。
在一个示例中，第二核心网设备从第一核心网设备接收第一切换请求的响应消息之后，本发明实施例的方法还可以包括：第二核心网设备向第二策略设备发送第七通知消息，第七通知消息用于通知第二策略设备：终端从第二制式网络切换到第一制式网络。
在这个示例中，第七通知消息携带第一IP地址、第三IP地址和第三使用信息，第三使用信息用于指示应用功能设备在第一制式网络中使用第三IP地 址替代第一IP地址，其中应用功能设备应用于第一制式网络和第二制式网络；
在这个示例中，第七通知消息还携带第二IP地址、第四IP地址和第四使用信息，第四使用信息用于指示应用功能设备在第一制式网络中使用第四IP地址替代第二IP地址。
在一个示例中，第二核心网设备从第一核心网设备接收第一切换请求的响应消息之后，本发明实施例的方法还可以包括：第二核心网设备向第一核心网设备发送切换完成确认消息；第二核心网设备向第二策略设备发送第九通知消息，第九通知消息用于通知第二策略设备：终端从第二制式网络切换到第一制式网络。
在这个示例中，第九通知消息携带第一IP地址、第三IP地址和第三使用信息，第三使用信息用于指示应用功能设备在第一制式网络中使用第三IP地址替代第一IP地址，其中应用功能设备应用于第一制式网络和第二制式网络。
在这个示例中，第九通知消息还可以携带第二IP地址、第四IP地址和第四使用信息，第四使用信息用于指示应用功能设备在第一制式网络中使用第四IP地址替代第二IP地址。
在203部分，第一核心网设备为终端在第一制式网络中发起第一APN的建立过程。
在一个示例中，第一核心网设备发起第一APN的过程可以包括：第一核心网设备基于第一IP地址向第一网关发送第一创建会话请求；第一核心网设备从第一网关接收第一创建会话响应，第一创建会话响应携带第一制式网络为终端分配的第三地址，第一创建会话响应用于指示所述终端使用所述第三IP地址。可见，本发明实施例中，终端在第一制式网络中所使用的第三IP地址与其在第二制式网络中所使用的第一IP地址相对应，即终端从第二制式网络切换到第一制式网络后，所使用的IP地址发生改变。
在这个示例中，第一核心网设备基于第一IP地址向第一网关发送第一创建会话请求之前，第一核心网设备还可以为终端向归属用户服务器发送位置更新请求消息；并从归属用户服务器接收位置更新确认消息。
在一种可能的实施方式中，第一核心网设备为终端在第一制式网络中发 起第一APN的建立过程之后，第一核心网设备还可以向第二核心网设备发送第一通知消息，第一通知消息用于通知第二核心网设备：第一核心网设备基于第一IP地址为终端建立了第一APN，第一通知消息携带第一IP地址和第三IP地址。
进一步的，第二核心网设备从第一核心网设备接收第一通知消息之后，第二核心网设备还可以向第二策略设备发送第三通知消息，第三通知消息用于通知第二策略设备：第一核心网设备基于第一IP地址为终端建立了第一APN，其中，第二策略设备应用于第二制式网络，第三通知消息中携带第三IP地址。
在一个示例中，第一核心网设备为终端在第一制式网络中发起第一APN的建立过程之后，第一核心网设备还可以为终端在第一制式网络中发起第二APN的建立过程。
在这个示例中，第一核心网设备发起第二APN的建立过程可以包括：第一核心网设备向第一网关发送第二创建会话请求；第一核心网设备从第一网关接收第二创建会话响应，第二创建会话响应携带第二APN建立过程中第一制式网络为终端分配的第四IP地址，第二创建会话响应用于指示终端使用第四IP地址。
在一种可能的实施方式中，第一核心网设备为终端在第一制式网络中发起第二接入点名称APN的建立过程之后，第一核心网设备还可以向第二核心网设备发送第二通知消息，第二通知消息用于通知第二核心网设备：第一核心网设备基于第二IP地址为终端建立了第二APN，第二通知消息携带所述第二IP地址和所述第四IP地址。
进一步的，第二核心网设备从第一核心网设备接收第二通知消息之后，第二核心网设备还可以向第二策略设备发送第三通知消息，第三通知消息用于通知第二策略设备：第一核心网设备基于第一IP地址为终端建立了第一APN，其中，第二策略设备应用于第二制式网络，第三通知消息中携带第三IP地址；或者，第二核心网设备从第一核心网设备接收第二通知消息之后，第二核心网设备还可以向第二策略设备发送第四通知消息，第四通知消息用于通知第二策略设备：第一核心网设备基于第二IP地址为终端建立了第二APN，其中，第 二策略设备应用于第二制式网络，所述第四通知消息中携带第四IP地址。
在一个示例中，第一核心网设备向第二核心网设备发送第一切换请求的响应消息之后，本发明实施例的方法还可以包括：第一核心网设备从第一网关接收承载创建请求消息；第一核心网设备从接入网设备接收切换到第一制式网络的完成消息；第一核心网设备向接入网设备发送承载建立请求消息；第一核心网设备从接入网设备接收承载建立响应消息；第一核心网设备向第一网关发送承载创建响应消息。
在这个示例中，第一核心网设备从接入网设备接收切换到第一制式网络的完成消息之后，本发明实施例的方法还可以包括：第一核心网设备向第二核心网设备发送切换完成通知消息；第一核心网设备从第二核心网设备接收切换完成确认消息。
在204部分，第一核心网设备向第一接入网设备发送第二切换请求。
其中，第一接入网设备应用于第一制式网络。
在一个示例中，第一核心网设备向所述接入网设备发送第二切换请求之前，第一核心网设备还可以从第一网关接收承载创建请求消息；并向第一网关发送承载创建响应消息。
在205部分，第一核心网设备从第一接入网设备接收第二切换请求的响应消息。
在206部分，第一核心网设备向第二核心网设备发送第一切换请求的响应消息。
对应的，第二核心网设备从第一核心网设备接收第一切换请求的响应消息。
其中，第一切换请求的响应消息携带第三IP地址。可选的，第一切换请求的响应消息还可以携带第四IP地址。
在一个示例中，所述第一切换请求的响应消息可以携带以下至少一项：附着接受消息，附着接受消息携带第一APN的信息、第一IP地址、第三IP地址和第一使用信息，第一使用信息用于指示终端在第一制式网络中使用第三IP地址替代第一IP地址；分组数据网络PDN连接建立接受消息，PDN连接 建立接受消息携带第二APN的信息；或者，会话管理SM请求消息，SM请求消息携带终端在第一制式网络的承载信息。
在一种可能的实施方式中，PDN连接建立接受消息还可以携带第二IP地址和第四IP地址和第二使用信息，第二使用信息用于指示终端在第一制式网络使用第四IP地址替代第二IP地址。
在207部分，第二核心网设备向第二接入网设备发送切换要求响应消息。
对应的，第二接入网设备从第二核心网设备接收切换要求响应消息。
在一个示例中，切换要求响应消息携带以下至少一项：上述附着接受消息、上述PDN连接建立接受消息或SM请求消息。其中，该附着接受消息、PDN连接建立接受消息或SM请求消息的内容可以参考上述206部分的详细描述，此处不作赘述。
在208部分，第二接入网设备向终端发送切换命令消息。
对应的，终端从第二接入网设备接收切换命令消息。
其中，所述切换命令消息携带以下至少一项：所述附着接受消息、所述PDN连接建立接受消息或所述SM请求消息。其中，该附着接受消息、PDN连接建立接受消息或SM请求消息的内容可以参考上述206部分的详细描述，此处不作赘述。
在一个示例中，PDN连接建立接受消息还携带第二IP地址、所第四IP地址和第二使用信息，所述第二使用信息用于指示终端在第一制式网络使用第四IP地址替代第二IP地址。
在一个示例中，终端在接收到切换命令消息之后，终端还可以不使用第五IP地址，第五IP地址是第二制式网络在终端接收来自第一接入网设备的切换命令消息之前为终端分配的IP地址。
在一个示例中，终端从第二接入网设备接收切换命令消息之前，终端还可以向第二核心网设备发送附着请求消息，附着请求消息用于请求附着到第一制式网络，其中，附着请求消息携带终端在第一制式网络的终端网络能力信息。
在一个示例中，终端从第二接入网设备接收切换命令消息之前，终端还可以从第二核心网设备接收查询请求消息；并向第二核心网设备发送查询请求 响应消息，查询请求响应消息携带终端在第一制式网络的终端网络能力信息。
在209部分，终端接入第一制式网络。
在一个示例中，终端可以根据所述附着接受消息、所述PDN连接建立接受消息或所述SM请求消息中的至少一项接入所述第一制式网络。
在210部分，终端向第一接入网设备发送切换完成消息。
下面结合更多的附图对本发明实施例的方案做进一步说明。
如图3所示，假设第一制式网络为4G网络、第二制式网络为5G网络，第一核心网设备为4G网络的移动性管理实体MME，第二核心网设备为5G网络的控制面功能CP Function实体，第一接入网设备为4G网络的演进型基站eNB，第二接入网设备为5G网络的下一代无线接入网NG RAN实体，第一网关为4G网络的服务网关SGW，第二网关为4G网络的PDN网关PGW，第一策略设备为4G网络的策略与计费规则功能PCRF实体，第二策略设备为5G网络的策略功能Policy Function实体；且4G网络中的PCRF实体和5G网络中的Policy Function实体独立部署，本发明实施例所公开的切换方法包括：
1a，终端将邻居小区信号测量结果上报给NG RAN实体，NG RAN实体决定将所述终端从5G网络切换到4G网络。
S301，所述NG RAN实体向所述CP Function实体发送切换要求消息(例如：Handover Required)。
S302，所述CP Function实体接收所述切换要求消息之后，向所述MME发送第一切换请求(例如：Forward Relocation Request)。
其中，由于所述终端包括诸如数据业务等默认业务，为保持该类业务的连续性，需要为该类业务建立第一接入点名称APN，通常情况下为Default APN，对应的，所述第一切换请求中携带有：第一互联网协议IP地址，所述第一IP地址用于第一APN的建立过程。
此外，当所述终端还包括诸如VoLTE(LTE网络语音业务)、ViLTE(LTE网络视频业务)等业务时，为保持该类业务的连续性，需要为该类业务建立第二APN，通常情况下为Dedicated APN，比如IMS APN，此种情况下，所述第一切换请求还可以携带有：所述终端的第二IP地址，所述第二IP地址用于第 二接入点名称APN的建立过程，其中所述第一IP地址以及所述第二IP地址是所述5G网络为所述终端分配的IP地址。
进一步地，所述第一切换请求还可能携带有以下至少一种：
所述终端的国际移动用户识别码(International Mobile Subscriber Identification Number，IMSI)、所述终端的安全上下文、所述终端的移动性管理上下文、所述终端的会话管理类上下文、所述终端在第一制式网络的终端网络能力信息。
其中，所述终端网络能力信息可通过如下两种途径获取：
途径1，所述终端在向所述CP Function实体发送的附着请求消息(例如：Attach Request)中携带所述终端网络能力信息。
途径2，所述CP Function实体向所述终端发送查询请求消息Query Request，所述终端在向所述CP Function实体发送的查询请求响应消息中携带所述终端网络能力信息。
更进一步地，所述第一切换请求还可以携带有预设的第一指示信息；该预设的第一指示信息用于指示MME在完成所述第一APN的建立过程之后，向CP Function实体发送第一通知消息。
更进一步地，所述第一切换请求还可以携带有预设的第二指示信息；该预设的第二指示信息用于指示MME在完成所述第二APN的建立过程之后，向CP Function实体发送第二通知消息。
S303，所述MME接收所述第一切换请求后，根据所述第一IP地址为所述终端在所述4G网络中发起所述第一APN的建立过程。
其中，第一APN的建立过程也称为第一APN的附着过程。
S304，所述MME完成所述第一APN的建立过程后，向所述CP Function实体发送所述第一通知消息(例如：Notify1)。
其中，所述第一通知消息中携带所述第一IP地址以及在所述第一APN的建立过程中为所述终端分配的第三IP地址；所述第一通知消息用于通知所述CP Function实体如下信息：所述MME基于所述第一IP地址为所述终端建立了所述第一APN。
需要注意的是，所述MME只有在检测到上述第一切换请求中携带有预设的所述第一指示信息的情况下，才会执行本步骤S304。
S305，所述CP Function实体接收所述第一通知消息后，向策略功能Policy Function实体发送第三通知消息(例如：Notify3)。
其中，所述第三通知消息中携带所述第一IP地址以及在所述第三IP地址；所述第三通知消息用于通知所述Policy Function实体如下信息：所述MME基于所述第一IP地址为所述终端建立了所述第一APN。
S306，所述Policy Function实体接收所述第三通知消息后，向应用功能AF设备发送第五通知消息(例如：Notify5)。
其中，所述第五通知消息中携带所述第一IP地址以及所述第三IP地址；所述第五通知消息用于通知所述Policy Function实体如下信息：所述MME基于所述第一IP地址为所述终端建立了所述第一APN。
S307，所述MME根据所述第二IP地址为所述终端在所述4G网络中发起所述第二APN的建立过程。
S308，所述MME完成所述第二APN的建立过程后，向所述CP Function实体发送所述第二通知消息(例如：Notify2)。
其中，所述第二通知消息中携带所述第二IP地址以及在所述第二APN的建立过程中为所述终端分配的第四IP地址；所述第二通知消息用于通知所述CP Function实体如下信息：所述MME基于所述第二IP地址为所述终端建立了所述第二APN。
需要注意的是，所述MME只有在检测到上述第一切换请求在携带有预设的所述第二指示信息的情况下，才会执行本步骤S308。
S309，所述CP Function实体接收所述第二通知消息，向所述策略功能Policy Function实体发送第四通知消息(例如：Notify4)。
其中，所述第四通知消息中携带所述第四IP地址；所述第四通知消息用于通知所述Policy Function实体如下信息：所述MME基于所述第二IP地址为所述终端建立了所述第二APN。
S310，所述Policy Function实体接收所述第四通知消息后，向所述AF设 备发送第六通知消息Notify6。
其中，所述第六通知消息中携带所述第四IP地址；所述第六通知消息用于通知所述AF设备如下信息：所述MME基于所述第二IP地址为所述终端建立了所述第二APN。
S311，所述AF设备接收所述第五通知消息或第六通知消息之后，使用所述第三IP地址(对应第五通知消息)或所述第四IP地址(对应第六通知消息)与所述终端进行信令面通信，同时向接入转发网关ATGW发送更新用户面请求消息(例如：Update User Plane Request)。
其中，所述更新用户面请求消息用于请求所述ATGW将用户面的所述第一IP地址更新为所述第三IP地址，或者，用于请求所述ATGW将用户面的所述第二IP地址更新为所述第四IP地址。
S312，所述AF设备从所述ATGW接收更新用户面请求响应消息(例如：Update User Plane Response)。
S313，所述AF设备接收所述第五通知消息或所述第六通知消息之后，发起第二承载的建立过程。
S314，所述MME检测到所述第一APN建立完成、所述第二APN建立完成(若存在)、所述第二承载建立完成(若存在)之后，向所述eNB发送第二切换请求(例如：Handover Request)。
S315，所述eNB接收所述第二切换请求后，向所述MME发送第二切换请求的响应消息(例如：Handover Request Acknowledge)。
S316，所述MME接收所述第二切换请求的响应消息后，向所述CP Function实体发送第一切换请求的响应消息(例如：Forward Relocation Response)，所述第一切换请求的响应消息携带所述第三IP地址。
其中，所述第一切换请求的响应消息携带有以下至少一种：
附着接受消息，所述附着接受消息携带所述第一APN的信息、所述第一IP地址、所述第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址；
分组数据网络PDN连接建立接受消息，所述PDN连接建立接受消息携 带所述第二APN的信息；
会话管理SM请求消息，所述SM请求消息携带所述终端在所述第一制式网络的承载信息。
S317，所述CP Function实体接收所述第一切换请求的响应消息后，向所述NG RAN实体发送切换要求响应消息(例如：Handover Required Response)。
其中，所述切换要求响应消息携带有以下至少一种：
附着接受消息，所述附着接受消息携带所述第一APN的信息、所述第一IP地址、所述第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址；
分组数据网络PDN连接建立接受消息，所述PDN连接建立接受消息携带所述第二APN的信息；
会话管理SM请求消息，所述SM请求消息携带所述终端在所述第一制式网络的承载信息。
可选地，所述PDN连接建立接受消息还携带所述第二IP地址、所述第四IP地址和第二使用信息，所述第二使用信息用于指示所述终端在第一制式网络使用所述第四IP地址替代所述第二IP地址。
S318，所述NG RAN实体接收所述切换要求响应消息后，向所述终端发送切换命令消息(例如：Handover Command)。
其中，所述切换命令消息携带以下至少一项：附着接受消息、分组数据网络PDN连接建立接受消息或会话管理SM请求消息。
其中，所述附着接受消息携带第一APN的信息、第一IP地址、第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述4G网络中使用所述第三IP地址替代所述第一IP地址，所述PDN连接建立接受消息携带所述MME为所述终端在所述4G网络建立的第二APN的信息，所述SM请求消息携带所述终端在所述4G网络的承载信息。
可选地，所述PDN连接建立接受消息还携带所述第二IP地址、所述第四IP地址和第二使用信息，所述第二使用信息用于指示所述终端在4G网络使用所述第四IP地址替代所述第二IP地址。
S319，所述终端向所述eNB实体发送切换完成消息(例如：Handover Complete)。
进一步地，请参阅图4，图4是图3中所描述的步骤S313中AF设备发起第二承载的创建过程的一种可能的实现方式，针对第二IP地址的第二承载建立过程与针对第一IP地址的第二承载的建立过程相同，以下以针对第一IP地址的第二承载的建立过程为例，说明第二承载的建立具体过程，具体包括以下步骤。
1a，所述AF设备为所述终端发起第二承载的建立过程之前，向所述Policy Function实体发送业务建立请求消息，也就是第一承载的建立请求，所述业务建立请求消息中携带业务要求信息；
其中，所述第一承载为所述终端的业务在所述5G网络中建立的承载，当所述终端从所述5G网络切换到所述4G网络，为保持业务连续性，所述4G网络为所述终端的业务时建立了第二承载，1a步骤主要是为了保证在第一承载建立过程中，所述AF设备将所述业务要求信息传递给所述Policy Function实体，保证所述4G网络中的所述PCRF实体和所述5G网络中的所述Policy Function实体合一部署时，所述Policy Function实体使用所述业务要求信息为所述终端的业务直接发起所述第二承载的建立过程。
S401，所述AF设备通过5G网络的第一IP地址查找到所述业务要求信息，并通过4G网络的第三IP地址寻址到所述PCRF实体之后，向PCRF实体发送认证授权请求(Authentication Authorization Request，AAR)消息。
其中，所述认证授权请求消息携带有所述第三IP地址；
S402，所述PCRF实体接收所述认证授权请求消息之后，通过所述第三IP地址寻址到PGW，向所述PGW发送重认证请求(Re-authentication Request，RAR)消息。
S403，所述PGW接收所述重新认证请求消息后，向所述PCRF实体发送重认证应答(Re-authentication Answer，RAA)消息。
S404，所述PCRF实体接收所述RAA后，向所述AF设备发送认证授权应答(Authentication Authorization Answer，AAA)消息。
S405，所述PGW通过所述SGW向MME发送承载创建请求消息(例如：Create Bearer Request)。
S406，所述SGW向所述MME转发所述承载创建请求消息。
S407，所述MME接收所述承载创建请求消息后，向所述SGW发送承载创建响应消息(例如：Create Bearer Response)。
S408，所述SGW向所述PGW转发所述承载创建响应消息。
如图5所示，假设第一制式网络为4G网络、第二制式网络为5G网络，第一核心网设备为4G网络的移动性管理实体MME，第二核心网设备为5G网络的控制面功能CP Function实体，第一接入网设备为4G网络的演进型基站eNB，第二接入网设备为5G网络的下一代无线接入网NG RAN实体，第一网关为4G网络的服务网关SGW，第二网关为4G网络的PDN网关PGW，第一策略设备为4G网络的策略与计费规则功能PCRF实体，第二策略设备为5G网络的策略功能Policy Function实体；且4G网络中的PCRF实体和5G网络中的Policy Function实体合一部署时，本发明实施例所公开的切换方法具体包括以下步骤。
1a，终端将邻居小区信号测量结果上报给所述NG RAN，所述NG RAN决定将所述终端从5G网络切换到4G网络。
S501，所述NG RAN实体向所述CP Function实体发送切换要求消息(例如：Handover Required)。
S502，所述CP Function实体接收所述切换要求消息之后，向所述MME发送第一切换请求(例如：Forward Relocation Request)。
其中，由于所述终端包括诸如数据业务等默认业务，为保持该类业务的连续性，需要为该类业务建立第一接入点名称APN，通常情况下为Default APN，对应的，所述第一切换请求中携带有第一互联网协议IP地址，所述第一IP地址用于第一APN的建立过程。
此外，当所述终端还包括诸如VoLTE、ViLTE等业务时，为保持该类业务的连续性，需要为该类业务建立第二APN，通常情况下为Dedicated APN，比如IMS APN，此种情况下，所述第一切换请求还可能携带：所述终端的第 二IP地址，所述第二IP地址用于第二接入点名称APN的建立过程，其中所述第一IP地址以及所述第二IP地址是所述5G网络为所述终端分配的IP地址。
进一步地，所述第一切换请求还可能携带有以下至少一种：
所述终端的国际移动用户识别码IMSI、UE的安全上下文、所述终端的移动性管理上下文、所述终端的会话管理类上下文、所述终端在4G网络的终端网络能力信息。
其中，所述终端网络能力信息可通过如下两种途径获取：
途径1、所述终端在向所述CP Function实体发送的附着请求(Attach Request)消息中携带所述终端网络能力信息。
途径2、所述CP Function实体向所述终端发送查询请求消息Query Request，所述终端在向所述CP Function实体发送的查询请求响应消息中携带所述终端网络能力信息。
更进一步地，所述第一切换请求还可以携带有预设的第一指示信息；该预设的第一指示信息用于指示MME在完成第一接入点名称APN的建立过程之后，向CP Function实体发送第一通知消息。
更进一步地，所述第一切换请求还可以携带有预设的第二指示信息；该预设的第二指示信息用于指示MME在完成第二接入点名称APN的建立过程之后，向CP Function实体发送第二通知消息。
S503，所述MME接收所述第一切换请求后根据所述第一IP地址为所述终端在所述4G网络中发起第一接入点名称APN的建立过程。
其中，所述第一APN的建立过程又可以称为第一APN的附着过程。
S504，所述MME完成所述第一APN的建立过程后，向所述CP Function实体发送所述第一通知消息(例如：Notify1)。
其中，所述第一通知消息中携带所述第一IP地址以及在所述第一APN的建立过程中为所述终端分配的第三IP地址；所述第一通知消息用于通知所述CP Function实体如下信息：所述MME基于所述第一IP地址为所述终端建立了所述第一APN。
需要注意的是，所述MME只有在检测到上述第一切换请求中携带有预 设的所述第一指示信息的情况下，才会执行本步骤S504。
S505，所述CP Function实体接收所述第一通知消息后，向Policy Function实体发送第三通知消息(例如：Notify3)。
其中，所述第三通知消息中携带所述第一IP地址以及在所述第三IP地址；所述第三通知消息用于通知所述Policy Function实体如下信息：所述MME基于所述第一IP地址为所述终端建立了所述第一APN。
S506，所述Policy Function实体接收所述第三通知消息后，向应用功能AF设备发送第五通知消息。
其中，所述第五通知消息中携带所述第一IP地址以及在所述第三IP地址；所述第五通知消息用于通知所述AF设备如下信息：所述MME基于所述第一IP地址为所述终端建立了所述第一APN。
S507，所述MME根据所述第二IP地址，为所述终端在所述4G网络中发起第二APN的建立过程。
S508，所述MME完成所述第二APN的建立过程后，向所述CP Function实体发送所述第二通知消息(例如：Notify2)。
其中，所述第二通知消息中携带所述第二IP地址以及在所述第二APN的建立过程中为所述终端分配的第四IP地址；所述第二通知消息用于通知所述CP Function实体如下信息：所述MME基于所述第二IP地址为所述终端建立了所述第二APN。
需要注意的是，所述MME只有在检测到上述第一切换请求在携带有预设的所述第二指示信息的情况下，才会执行本步骤S508。
S509，所述CP Function实体接收所述第二通知消息，向所述策略功能Policy Function实体发送第四通知消息(例如：Notify4)。
其中，所述第四通知消息中携带所述第二IP地址以及在所述第二APN的建立过程中为所述终端分配的第四IP地址；所述第四通知消息用于通知所述Policy Function实体如下信息：所述MME基于所述第二IP地址为所述终端建立了所述第二APN。
S510，所述Policy Function实体接收所述第四通知消息后，向所述AF设 备发送第六通知消息(例如：Notify6)。
其中，所述第六通知消息中携带所述第二IP地址以及在所述第二APN的建立过程中为所述终端分配的第四IP地址；所述第六通知消息用于通知所述AF设备如下信息：所述MME基于所述第二IP地址为所述终端建立了所述第二APN。
S511，所述AF设备接收所述第五通知消息或第六通知消息之后，使用所述第三IP地址(对应第五通知消息)或所述第四IP地址(对应第六通知消息)与所述终端进行信令面通信，同时向接入转发网关ATGW发送更新用户面请求消息(例如：Update User Plane Request)。
其中，所述更新用户面请求消息用于请求所述ATGW将用户面的所述第一IP地址更新为所述第三IP地址，或者，用于请求所述ATGW将用户面的所述第二IP地址更新为所述第四IP地址。
S512，所述AF设备从所述ATGW接收更新用户面请求响应消息(例如：Update User Plane Response)。
S513，所述Policy Function实体接收所述第五通知消息或第六通知消息之后，发起第二承载的建立过程。
S514，所述MME检测到所述第一APN建立完成、所述第二APN建立完成(若存在)、所述第二承载建立完成(若存在)之后，向所述eNB发送第二切换请求(例如：Handover Request)。
S515，所述eNB接收所述第二切换请求后，向所述MME发送第二切换请求的响应消息(例如：Handover Request Acknowledge)。
S516，所述MME接收所述第二切换请求的响应消息后，向所述CP Function实体发送第一切换请求的响应消息(例如：Forward Relocation Response)。
其中，所述第一切换请求的响应消息携带有以下至少一种：附着接受消息，所述附着接受消息携带所述第一APN的信息、所述第一IP地址、所述第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址；分组数据网络PDN 连接建立接受消息，所述PDN连接建立接受消息携带所述第二APN的信息；会话管理SM请求消息，所述SM请求消息携带所述终端在所述第一制式网络的承载信息。
可选地，所述PDN连接建立接受消息携带有所述第二IP地址、所述第四IP地址和第二使用信息，所述第二使用信息用于指示所述终端在4G网络使用所述第四IP地址替代所述第二IP地址。
S517，所述CP Function实体接收所述第一切换请求的响应消息后，向所述NG RAN实体发送切换要求响应消息(例如：Handover Required Response)。
其中，所述切换要求响应消息携带有以下至少一种：
附着接受消息，所述附着接受消息携带所述第一APN的信息、所述第一IP地址、所述第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址；
分组数据网络PDN连接建立接受消息，所述PDN连接建立接受消息携带所述第二APN的信息；
会话管理SM请求消息，所述SM请求消息携带所述终端在所述第一制式网络的承载信息。
可选地，所述PDN连接建立接受消息还携带所述第二IP地址和所述第四IP地址和第二使用信息，所述第二使用信息用于指示所述终端在4G网络使用所述第四IP地址替代所述第二IP地址。
S518，所述NG RAN实体接收所述切换要求响应消息后，向所述终端发送切换命令消息(例如：Handover Command)。
其中，所述切换命令消息携带有以下至少一种：附着接受消息、分组数据网络PDN连接建立接受消息或会话管理SM请求消息；其中，所述附着接受消息携带第一核心网设备为所述终端在所述第一制式网络建立的第一接入点名称APN的信息、所述第二制式网络为所述终端分配的第一互联网协议IP地址、所述第一制式网络在所述第一APN的建立过程中为所述终端分配的第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，所述PDN连接建立 接受消息携带所述第一核心网设备为所述终端在所述第一制式网络建立的第二APN的信息，所述SM请求消息携带所述终端在所述第一制式网络的承载信息。
可选地，所述PDN连接建立接受消息还携带所述第二IP地址、所述第四IP地址和第二使用信息，所述第二使用信息用于指示所述终端在4G网络使用所述第四IP地址替代所述第二IP地址。
S519，所述终端向所述eNB实体发送切换完成消息(例如：Handover Complete)。
进一步地，请参阅图6，图6是图5中所描述的步骤S513中专有第二承载的创建过程的一种可能的实现方式，针对第二IP地址的第二承载建立过程与针对第一IP地址的第二承载的建立过程相同，以下以针对第一IP地址的第二承载的建立过程为例，说明第二承载的建立具体过程，具体包括以下步骤。
1a，所述Policy Function实体为终端发起第二承载的建立过程之前，从AF设备接收业务建立请求消息，也就是第一承载的建立请求，所述业务建立请求消息中携带业务要求信息；
其中，所述第一承载为所述终端的所述业务在所述5G网络中建立的承载，当所述终端从所述5G网络切换到所述4G网络，为保持所述业务连续性，所述4G网络为所述终端的所述业务时建立了第二承载，1a步骤主要是为了保证在第一承载建立过程中，所述Policy Function实体从所述AF实体接收所述业务要求信息，保证所述4G网络中的PCRF实体和所述5G网络中的Policy Function实体合一部署时，所述Policy Function实体可以使用所述业务要求信息为所述终端的所述业务直接发起所述第二承载的建立过程。
S601，所述Policy Function实体通过5G网络的第一IP地址查找到业务要求信息，并通过4G网络的第三IP地址寻址到所述PGW，并向所述PGW发送重新认证请求消息。
S602，所述PGW接收所述重新认证请求消息后，向所述PCRF实体发送重新认证应答消息。
S603，所述PGW向所述SGW发送承载创建请求消息(例如：Create Bearer  Request)。
S604，所述SGW向所述MME转发所述承载创建请求消息。
S605，所述MME接收所述承载创建请求消息后，向SGW发送承载创建响应消息(例如：Create Bearer Response)。
S606，所述SGW向所述PGW转发所述承载创建响应消息。
如图3a所示，假设第一制式网络为4G网络、第二制式网络为5G网络，第一核心网设备为4G网络的移动性管理实体MME，第二核心网设备为5G网络的控制面功能CP Function实体，第一接入网设备为4G网络的演进型基站eNB，第二接入网设备为5G网络的下一代无线接入网NG RAN实体，第一网关为4G网络的服务网关SGW，第二网关为4G网络的PDN网关PGW，第一策略设备为4G网络的策略与计费规则功能PCRF实体，第二策略设备为5G网络的策略功能Policy Function实体；且4G网络中的PCRF实体和5G网络中的Policy Function实体独立部署，本发明实施例所公开的切换方法包括：
1a、终端将邻居小区信号测量结果上报给NG RAN实体，NG RAN实体决定将所述终端从5G网络切换到4G网络。
S3a01，所述NG RAN实体向所述CP Function实体发送切换要求消息(例如：Handover Required)。
S3a02，所述CP Function实体接收所述切换要求消息之后，向所述MME发送第一切换请求(例如：Forward Relocation Request)。
其中，由于所述终端包括诸如数据业务等默认业务，为保持该类业务的连续性，需要为该类业务建立第一接入点名称APN，通常情况下为Default APN，对应的，所述第一切换请求中携带有：第一互联网协议IP地址，所述第一IP地址用于第一APN的建立过程。
此外，当所述终端还包括诸如VoLTE(LTE网络语音业务)、ViLTE(LTE网络视频业务)等业务时，为保持该类业务的连续性，需要为该类业务建立第二APN，通常情况下为Dedicated APN，比如IMS APN，此种情况下，所述第一切换请求还可以携带有：所述终端的第二IP地址，所述第二IP地址用于第二接入点名称APN的建立过程，其中所述第一IP地址以及所述第二IP地址 是所述5G网络为所述终端分配的IP地址。
进一步地，所述第一切换请求还可能携带有以下至少一种：
所述终端的国际移动用户识别码(International Mobile Subscriber Identification Number，IMSI)、所述终端的安全上下文、所述终端的移动性管理上下文、所述终端的会话管理类上下文、所述终端在第一制式网络的终端网络能力信息。
其中，所述终端网络能力信息可通过如下两种途径获取：
途径1，所述终端在向所述CP Function实体发送的附着请求消息(例如：Attach Request)中携带所述终端网络能力信息。
途径2，所述CP Function实体向所述终端发送查询请求消息Query Request，所述终端在向所述CP Function实体发送的查询请求响应消息中携带所述终端网络能力信息。
S3a03，所述MME接收所述第一切换请求后，为所述终端在所述4G网络中发起第一接入点名称APN的建立过程。
S3a04，所述MME为所述终端在所述4G网络中发起第二接入点APN的建立过程。
S3a05，所述MME检测到所述第一APN建立完成、所述第二APN建立完成(若存在)之后，向所述eNB发送第二切换请求(例如：Handover Request)。
S3a06，所述eNB接收所述第二切换请求后，向所述MME发送第二切换请求的响应消息(例如：Handover Request Acknowledge)。
S3a07，所述MME接收所述第二切换请求的响应消息后，向所述CP Function实体发送第一切换请求的响应消息(例如：Forward Relocation Response)，所述第一切换请求的响应消息携带所述第三IP地址。
其中，所述第一切换请求的响应消息携带有以下至少一种：
附着接受消息，所述附着接受消息携带所述第一APN的信息、所述第一IP地址、所述第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址；
分组数据网络PDN连接建立接受消息，所述PDN连接建立接受消息携 带所述第二APN的信息。
S3a08，所述CP Function实体接收所述第一切换请求响应后，向所述Policy Function实体发送第七通知消息(例如：Notify7)。
其中，所述第七通知消息用于通知所述Policy Function实体如下信息：所述终端从所述5G网络切换到所述4G网络，所述第七通知消息携带所述第一IP地址、所述第三IP地址和第三使用信息，所述第三使用信息用于指示应用功能设备在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，其中所述应用功能设备应用于所述第一制式网络和所述第二制式网络。可选的，所述七通知消息还可以携带所述第二IP地址、所述第四IP地址和第四使用信息，所述第四使用信息用于指示所述应用功能设备在所述第一制式网络中使用所述第四IP地址替代所述第二IP地址。
可选地，所述CP Function实体如果与所述PGW-C实体合一部署，也就是说，所述CP Function拥有PGW-C的功能，S3a02步骤中所述第一切换请求可以不携带所述第一IP地址或者所述第二IP地址，而是直接携带所述CP Function的地址，其中所述CP Function的地址用于在步骤S3a03的所述第一APN的建立过程中、步骤S3a04的所述第二APN的建立过程中寻址所述CP Function实体，在这种情况下，所述CP Function实体接收所述第一切换请求响应后，向所述Policy Function实体发送所述第七通知消息Notify7。
S3a09，所述Policy Function实体接收所述第七通知消息后，向所述AF设备发送第八通知消息(例如：Notify8)。
其中，所述第八通知消息用于通知所述AF设备如下信息：所述终端从所述5G网络切换到所述4G网络，所述第八通知消息携带所述第一IP地址、所述第三IP地址和第三使用信息，所述第三使用信息用于指示应用功能设备在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，其中所述应用功能设备应用于第一制式网络和第二制式网络。可选的，所述八通知消息还可以携带所述第二IP地址、所述第四IP地址和第四使用信息，所述第四使用信息用于指示所述应用功能设备在所述第一制式网络中使用所述第四IP地址替代所述第二IP地址。
S3a10，所述AF设备接收所述第八通知消息之后，使用所述第三IP地址或所述第四IP地址(若存在)与所述终端进行信令面通信，同时向接入转发网关ATGW发送更新用户面请求消息(例如：Update User Plane Request)。
其中，所述更新用户面请求消息用于请求所述ATGW将用户面的所述第一IP地址更新为所述第三IP地址，或者，用于请求所述ATGW将用户面的所述第二IP地址更新为所述第四IP地址。
S3a11，所述AF设备从所述ATGW接收更新用户面请求响应消息(例如：Update User Plane Response)。
S3a12，AF设备接收所述第八通知消息后，发起第二承载的创建过程。
其中，S3a15的具体流程请参见图4a。
如图3b所示，假设第一制式网络为4G网络、第二制式网络为5G网络，第一核心网设备为4G网络的移动性管理实体MME，第二核心网设备为5G网络的控制面功能CP Function实体，第一接入网设备为4G网络的演进型基站eNB，第二接入网设备为5G网络的下一代无线接入网NG RAN实体，第一网关为4G网络的服务网关SGW，第二网关为4G网络的PDN网关PGW，第一策略设备为4G网络的策略与计费规则功能PCRF实体，第二策略设备为5G网络的策略功能Policy Function实体；且4G网络中的PCRF实体和5G网络中的Policy Function实体独立部署，本发明实施例所公开的切换方法包括：
1a、终端将邻居小区信号测量结果上报给NG RAN实体，NG RAN实体决定将所述终端从5G网络切换到4G网络。
S3b01，所述NG RAN实体向所述CP Function实体发送切换要求消息(例如：Handover Required)。
S3b02，所述CP Function实体接收所述切换要求消息之后，向所述MME发送第一切换请求(例如：Forward Relocation Request)。
其中，由于所述终端包括诸如数据业务等默认业务，为保持该类业务的连续性，需要为该类业务建立第一接入点名称APN，通常情况下为Default APN，对应的，所述第一切换请求中携带有：第一互联网协议IP地址，所述第一IP地址用于第一APN的建立过程。
此外，当所述终端还包括诸如VoLTE(LTE网络语音业务)、ViLTE(LTE网络视频业务)等业务时，为保持该类业务的连续性，需要为该类业务建立第二APN，通常情况下为Dedicated APN，比如IMS APN，此种情况下，所述第一切换请求还可以携带有：所述终端的第二IP地址，所述第二IP地址用于第二接入点名称APN的建立过程，其中所述第一IP地址以及所述第二IP地址是所述5G网络为所述终端分配的IP地址。
进一步地，所述第一切换请求还可能携带有以下至少一种：
所述终端的国际移动用户识别码(International Mobile Subscriber Identification Number，IMSI)、所述终端的安全上下文、所述终端的移动性管理上下文、所述终端的会话管理类上下文、所述终端在第一制式网络的终端网络能力信息。
其中，所述终端网络能力信息可通过如下两种途径获取：
途径1，所述终端在向所述CP Function实体发送的附着请求消息(例如：Attach Request)中携带所述终端网络能力信息。
途径2，所述CP Function实体向所述终端发送查询请求消息Query Request，所述终端在向所述CP Function实体发送的查询请求响应消息中携带所述终端网络能力信息。
S3b03，所述MME接收所述第一切换请求后，为所述终端在所述4G网络中发起第一接入点名称APN的建立过程。
S3b04，所述MME为所述终端在所述4G网络中发起第二接入点APN的建立过程。
S3b05，所述MME检测到所述第一APN建立完成、所述第二APN建立完成(若存在)之后，向所述eNB发送第二切换请求(例如：Handover Request)。
S3b06，所述eNB接收所述第二切换请求后，向所述MME发送第二切换请求的响应消息(例如：Handover Request Acknowledge)。
S3b07，所述MME接收所述第二切换请求的响应消息后，向所述CP Function实体发送第一切换请求的响应消息(例如：Forward Relocation Response)，所述第一切换请求的响应消息携带所述第三IP地址。
其中，所述第一切换请求的响应消息携带有以下至少一种：
附着接受消息，所述附着接受消息携带所述第一APN的信息、所述第一IP地址、所述第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址；
分组数据网络PDN连接建立接受消息，所述PDN连接建立接受消息携带所述第二APN的信息。
S3b08，所述CP Function实体接收所述第一切换请求的响应消息后，向所述NG RAN实体发送切换要求响应消息(例如：Handover Required Response)。
其中，所述切换要求响应消息携带有以下至少一种：
附着接受消息，所述附着接受消息携带所述第一APN的信息、所述第一IP地址、所述第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址；
分组数据网络PDN连接建立接受消息，所述PDN连接建立接受消息携带所述第二APN的信息。
可选地，所述PDN连接建立接受消息还携带所述第二IP地址、所述第四IP地址和第二使用信息，所述第二使用信息用于指示所述终端在第一制式网络使用所述第四IP地址替代所述第二IP地址。
S3b09，所述NG RAN实体接收所述切换要求响应消息后，向所述终端发送切换命令消息(例如：Handover Command)。
其中，所述切换命令消息携带以下至少一项：附着接受消息、分组数据网络PDN连接建立接受消息。
其中，所述附着接受消息携带第一APN的信息、第一IP地址、第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述4G网络中使用所述第三IP地址替代所述第一IP地址，所述PDN连接建立接受消息携带所述MME为所述终端在所述4G网络建立的第二APN的信息。
可选地，所述PDN连接建立接受消息还携带所述第二IP地址、所述第四IP地址和第二使用信息，所述第二使用信息用于指示所述终端在4G网络 使用所述第四IP地址替代所述第二IP地址。
S3b10，所述终端向所述eNB实体发送切换完成消息(例如：Handover Complete)。
S3b11，所述eNB实体接收到所述切换完成消息后，向所述MME实体发送切换到4G网络的完成消息(例如：Handover to E-UTRAN Complete)；
S3b12，所述MME实体收到所述切换到4G网络的完成消息后，向所述CP Function实体发送切换完成通知消息(例如：Forward Relocation Complete Notification)。
S3b13，所述CP Function实体接收到所述切换完成通知消息后，向所述MME实体发送切换完成确认消息(例如：Forward Relocation Complete Acknowledge)。
S3b14，所述CP Function实体发送所述切换完成确认消息后，向所述Policy Function实体发送第九通知消息(例如：Notify9)。
其中，所述第九通知消息用于通知所述Policy Function实体如下信息：所述终端从所述5G网络切换到所述4G网络，所述第九通知消息携带所述第一IP地址、所述第三IP地址和第三使用信息，所述第三使用信息用于指示应用功能设备在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，其中所述应用功能设备应用于所述第一制式网络和所述第二制式网络。可选的，所述九通知消息还可以携带所述第二IP地址、所述第四IP地址和第四使用信息，所述第四使用信息用于指示所述应用功能设备在所述第一制式网络中使用所述第四IP地址替代所述第二IP地址。
可选地，所述CP Function实体如果与所述PGW-C实体合一部署，也就是说，所述CP Function拥有PGW-C的功能，S3b02步骤中所述第一切换请求可以不携带所述第一IP地址或者所述第二IP地址，而是直接携带所述CP Function的地址，其中所述CP Function的地址用于在步骤S3b03的所述第一APN的建立过程中、步骤S3b04的所述第二APN的建立过程中寻址所述CP Function实体，在这种情况下，所述CP Function实体发送所述切换完成确认消息后，向所述Policy Function实体发送所述第九通知消息Notify9。
S3b15，所述Policy Function实体接收所述第九通知消息后，向所述AF设备发送第十通知消息(例如：Notify10)。
其中，所述第十通知消息用于通知所述AF设备如下信息：所述终端从所述5G网络切换到所述4G网络，所述第十通知消息携带所述第一IP地址、所述第三IP地址和第三使用信息，所述第三使用信息用于指示应用功能设备在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，其中所述应用功能设备应用于所述第一制式网络和所述第二制式网络。可选的，所述十通知消息还可以携带所述第二IP地址、所述第四IP地址和第四使用信息，所述第四使用信息用于指示所述应用功能设备在所述第一制式网络中使用所述第四IP地址替代所述第二IP地址。
S3b16，所述AF设备接收所述第十通知消息之后，使用所述第三IP地址或所述第四IP地址(若存在)与所述终端进行信令面通信，同时向接入转发网关ATGW发送更新用户面请求消息(例如：Update User Plane Request)。
其中，所述更新用户面请求消息用于请求所述ATGW将用户面的所述第一IP地址更新为所述第三IP地址，或者，用于请求所述ATGW将用户面的所述第二IP地址更新为所述第四IP地址。
S3b17，所述AF设备从所述ATGW接收更新用户面请求响应消息(例如：Update User Plane Response)。
S3b18，AF设备接收所述第十通知消息后，发起第二承载的创建过程。
所述第二承载的创建过程为现网流程，不再赘述。
如图3c所示，假设第一制式网络为4G网络、第二制式网络为5G网络，第一核心网设备为4G网络的移动性管理实体MME，第二核心网设备为5G网络的控制面功能CP Function实体，第一接入网设备为4G网络的演进型基站eNB，第二接入网设备为5G网络的下一代无线接入网NG RAN实体，第一网关为4G网络的服务网关SGW，第二网关为4G网络的PDN网关PGW，第一策略设备为4G网络的策略与计费规则功能PCRF实体，第二策略设备为5G网络的策略功能Policy Function实体；且4G网络中的PCRF实体和5G网络中的Policy Function实体独立部署，本发明实施例所公开的切换方法包括：
1a、终端将邻居小区信号测量结果上报给NG RAN实体，NG RAN实体决定将所述终端从5G网络切换到4G网络。
S3c01，所述NG RAN实体向所述CP Function实体发送切换要求消息(例如：Handover Required)。
S3c02，所述CP Function实体接收所述切换要求消息之后，向所述MME发送第一切换请求(例如：Forward Relocation Request)。
其中，由于所述终端包括诸如数据业务等默认业务，为保持该类业务的连续性，需要为该类业务建立第一接入点名称APN，通常情况下为Default APN，对应的，所述第一切换请求中携带有：第一互联网协议IP地址，所述第一IP地址用于第一APN的建立过程。
此外，当所述终端还包括诸如VoLTE(LTE网络语音业务)、ViLTE(LTE网络视频业务)等业务时，为保持该类业务的连续性，需要为该类业务建立第二APN，通常情况下为Dedicated APN，比如IMS APN，此种情况下，所述第一切换请求还可以携带有：所述终端的第二IP地址，所述第二IP地址用于第二接入点名称APN的建立过程，其中所述第一IP地址以及所述第二IP地址是所述5G网络为所述终端分配的IP地址。
进一步地，所述第一切换请求还可能携带有以下至少一种：
所述终端的国际移动用户识别码(International Mobile Subscriber Identification Number，IMSI)、所述终端的安全上下文、所述终端的移动性管理上下文、所述终端的会话管理类上下文、所述终端在第一制式网络的终端网络能力信息。
其中，所述终端网络能力信息可通过如下两种途径获取：
途径1，所述终端在向所述CP Function实体发送的附着请求消息(例如：Attach Request)中携带所述终端网络能力信息。
途径2，所述CP Function实体向所述终端发送查询请求消息Query Request，所述终端在向所述CP Function实体发送的查询请求响应消息中携带所述终端网络能力信息。
S3c03，所述MME接收所述第一切换请求后，为所述终端在所述4G网 络中发起第一接入点名称APN的建立过程。
S3c04，所述MME为所述终端在所述4G网络中发起第二接入点APN的建立过程。
S3c05，所述MME检测到所述第一APN建立完成、所述第二APN建立完成(若存在)之后，向所述eNB发送第二切换请求(例如：Handover Request)。
S3c06，所述eNB接收所述第二切换请求后，向所述MME发送第二切换请求的响应消息(例如：Handover Request Acknowledge)。
S3c07，所述MME接收所述第二切换请求的响应消息后，向所述CP Function实体发送第一切换请求的响应消息(例如：Forward Relocation Response)，所述第一切换请求的响应消息携带所述第三IP地址。
其中，所述第一切换请求的响应消息携带有以下至少一种：
附着接受消息，所述附着接受消息携带所述第一APN的信息、所述第一IP地址、所述第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址；
分组数据网络PDN连接建立接受消息，所述PDN连接建立接受消息携带所述第二APN的信息。
S3c08，所述CP Function实体接收所述第一切换请求的响应消息后，向所述NG RAN实体发送切换要求响应消息(例如：Handover Required Response)。
其中，所述切换要求响应消息携带有以下至少一种：
附着接受消息，所述附着接受消息携带所述第一APN的信息、所述第一IP地址、所述第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址；
分组数据网络PDN连接建立接受消息，所述PDN连接建立接受消息携带所述第二APN的信息。
可选地，所述PDN连接建立接受消息还携带所述第二IP地址、所述第四IP地址和第二使用信息，所述第二使用信息用于指示所述终端在第一制式网络使用所述第四IP地址替代所述第二IP地址。
S3c09，所述NG RAN实体接收所述切换要求响应消息后，向所述终端发送切换命令消息(例如：Handover Command)。
其中，所述切换命令消息携带以下至少一项：附着接受消息、分组数据网络PDN连接建立接受消息。
其中，所述附着接受消息携带第一APN的信息、第一IP地址、第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述4G网络中使用所述第三IP地址替代所述第一IP地址，所述PDN连接建立接受消息携带所述MME为所述终端在所述4G网络建立的第二APN的信息。
可选地，所述PDN连接建立接受消息还携带所述第二IP地址、所述第四IP地址和第二使用信息，所述第二使用信息用于指示所述终端在4G网络使用所述第四IP地址替代所述第二IP地址。
S3c10，所述终端向所述eNB实体发送切换完成消息(例如：Handover Complete)。
S3c11，所述终端接收所述切换完成消息后，向所述AF设备发送第十一通知消息(例如：Notify11)，这里所述终端可以通过会话发起协议SIP信令向所述AF设备发送所述第十一通知消息。
其中，所述第十一通知消息用于通知所述AF设备如下信息：所述终端从所述5G网络切换到所述4G网络，所述第十一通知消息携带所述第一IP地址、所述第三IP地址和第三使用信息，所述第三使用信息用于指示应用功能设备在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，其中所述应用功能设备应用于所述第一制式网络和所述第二制式网络。可选的，所述十一通知消息还可以携带所述第二IP地址、所述第四IP地址和第四使用信息，所述第四使用信息用于指示所述应用功能设备在所述第一制式网络中使用所述第四IP地址替代所述第二IP地址。
S3c12，所述AF设备接收所述第十一通知消息之后，使用所述第三IP地址或所述第四IP地址(若存在)与所述终端进行信令面通信，同时向接入转发网关ATGW发送更新用户面请求消息(例如：Update User Plane Request)。
其中，所述更新用户面请求消息用于请求所述ATGW将用户面的所述第 一IP地址更新为所述第三IP地址，或者，用于请求所述ATGW将用户面的所述第二IP地址更新为所述第四IP地址。
S3a13，所述AF设备从所述ATGW接收更新用户面请求响应消息(例如：Update User Plane Response)。
S3c14，AF设备接收所述第十一通知消息后，发起第二承载的创建过程；
所述第二承载的创建过程为现网流程，不再赘述。
如图3d所示，假设第一制式网络为4G网络、第二制式网络为5G网络，第一核心网设备为4G网络的移动性管理实体MME，第二核心网设备为5G网络的控制面功能CP Function实体，第一接入网设备为4G网络的演进型基站eNB，第二接入网设备为5G网络的下一代无线接入网NG RAN实体，第一网关为4G网络的服务网关SGW，第二网关为4G网络的PDN网关PGW，第一策略设备为4G网络的策略与计费规则功能PCRF实体，第二策略设备为5G网络的策略功能Policy Function实体；且4G网络中的PCRF实体和5G网络中的Policy Function实体独立部署，本发明实施例所公开的切换方法包括：
1a、终端将邻居小区信号测量结果上报给NG RAN实体，NG RAN实体决定将所述终端从5G网络切换到4G网络。
S3d01，所述NG RAN实体向所述CP Function实体发送切换要求消息(例如：Handover Required)。
S3d02，所述CP Function实体接收所述切换要求消息之后，向所述MME发送第一切换请求(例如：Forward Relocation Request)。
其中，由于所述终端包括诸如数据业务等默认业务，为保持该类业务的连续性，需要为该类业务建立第一接入点名称APN，通常情况下为Default APN，对应的，所述第一切换请求中携带有：第一互联网协议IP地址，所述第一IP地址用于第一APN的建立过程。
此外，当所述终端还包括诸如VoLTE(LTE网络语音业务)、ViLTE(LTE网络视频业务)等业务时，为保持该类业务的连续性，需要为该类业务建立第二APN，通常情况下为Dedicated APN，比如IMS APN，此种情况下，所述第一切换请求还可以携带有：所述终端的第二IP地址，所述第二IP地址用于第 二接入点名称APN的建立过程，其中所述第一IP地址以及所述第二IP地址是所述5G网络为所述终端分配的IP地址。
进一步地，所述第一切换请求还可能携带有以下至少一种：
所述终端的国际移动用户识别码(International Mobile Subscriber Identification Number，IMSI)、所述终端的安全上下文、所述终端的移动性管理上下文、所述终端的会话管理类上下文、所述终端在第一制式网络的终端网络能力信息。
其中，所述终端网络能力信息可通过如下两种途径获取：
途径1，所述终端在向所述CP Function实体发送的附着请求消息(例如：Attach Request)中携带所述终端网络能力信息。
途径2，所述CP Function实体向所述终端发送查询请求消息Query Request，所述终端在向所述CP Function实体发送的查询请求响应消息中携带所述终端网络能力信息。
S3d03，所述MME接收所述第一切换请求后，为所述终端在所述4G网络中发起第一接入点名称APN的建立过程。
S3d04，所述MME为所述终端在所述4G网络中发起第二接入点APN的建立过程。
S3d05，所述MME检测到所述第一APN建立完成、所述第二APN建立完成(若存在)之后，向所述eNB发送第二切换请求(例如：Handover Request)。
S3d06，所述eNB接收所述第二切换请求后，向所述MME发送第二切换请求的响应消息(例如：Handover Request Acknowledge)。
S3d07，所述MME接收所述第二切换请求的响应消息后，向所述CP Function实体发送第一切换请求的响应消息(例如：Forward Relocation Response)，所述第一切换请求的响应消息携带所述第三IP地址。
其中，所述第一切换请求的响应消息携带有以下至少一种：
附着接受消息，所述附着接受消息携带所述第一APN的信息、所述第一IP地址、所述第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址；
分组数据网络PDN连接建立接受消息，所述PDN连接建立接受消息携带所述第二APN的信息。
S3d08，所述CP Function实体接收所述第一切换请求的响应消息后，向所述NG RAN实体发送切换要求响应消息(例如：Handover Required Response)。
其中，所述切换要求响应消息携带有以下至少一种：
附着接受消息，所述附着接受消息携带所述第一APN的信息、所述第一IP地址、所述第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址；
分组数据网络PDN连接建立接受消息，所述PDN连接建立接受消息携带所述第二APN的信息。
可选地，所述PDN连接建立接受消息还携带所述第二IP地址、所述第四IP地址和第二使用信息，所述第二使用信息用于指示所述终端在第一制式网络使用所述第四IP地址替代所述第二IP地址。
S3d09，所述NG RAN实体接收所述切换要求响应消息后，向所述终端发送切换命令消息(例如：Handover Command)。
其中，所述切换命令消息携带以下至少一项：附着接受消息、分组数据网络PDN连接建立接受消息。
其中，所述附着接受消息携带第一APN的信息、第一IP地址、第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述4G网络中使用所述第三IP地址替代所述第一IP地址，所述PDN连接建立接受消息携带所述MME为所述终端在所述4G网络建立的第二APN的信息。
可选地，所述PDN连接建立接受消息还携带所述第二IP地址、所述第四IP地址和第二使用信息，所述第二使用信息用于指示所述终端在4G网络使用所述第四IP地址替代所述第二IP地址。
S3d10，所述终端向所述eNB实体发送切换完成消息(例如：Handover Complete)。
S3d11，所述终端接收所述切换完成消息后，发起第二承载的创建过程；
所述第二承载的创建过程为现网流程，不再赘述。
进一步地，请参阅图4a，图4a是图3a中所描述的步骤3a15中AF设备发起第二承载的创建过程的一种可能的实现方式，该针对第二IP地址的第二承载建立过程，与第一IP地址的第一承载的建立过程相同，以下以第二IP地址为例，说明第二承载的建立具体过程，具体包括以下步骤：
1a，所述AF设备为所述终端发起第二承载的建立过程之前，向所述Policy Function实体发送业务建立请求消息，也就是第一承载的建立请求，所述业务建立请求消息中携带业务要求信息；
其中，所述第一承载为所述终端的业务在所述5G网络中建立的承载，当所述终端从所述5G网络切换到所述4G网络，为保持业务连续性，所述4G网络为所述终端的业务时建立了第二承载，1a步骤主要是为了保证在第一承载建立过程中，所述AF设备将所述业务要求信息传递给所述Policy Function实体，保证所述4G网络中的所述PCRF实体和所述5G网络中的所述Policy Function实体合一部署时，所述Policy Function实体使用所述业务要求信息为所述终端的业务直接发起所述第二承载的建立过程。
S4a01，所述AF设备通过5G网络的第一IP地址查找到所述业务要求信息，并通过4G网络的第三IP地址寻址到所述PCRF实体之后，向PCRF实体发送认证授权请求(Authentication Authorization Request，AAR)消息。
其中，所述认证授权请求消息携带有所述第三IP地址；
S4a02，所述PCRF实体接收所述认证授权请求消息之后，通过所述第三IP地址寻址到PGW，向所述PGW发送重认证请求(Re-authentication Request，RAR)消息。
S4a03，所述PGW接收所述重新认证请求消息后，向所述PCRF实体发送重认证应答(Re-authentication Answer，RAA)消息。
S4a04，所述PCRF实体接收所述RAA后，向所述AF设备发送认证授权应答(Authentication Authorization Answer，AAA)消息。
Sa405，所述PGW通过所述SGW向MME发送承载创建请求消息(例如：Create Bearer Request)。
S4a06，所述SGW向所述MME转发所述承载创建请求消息。
S4a07-S4a09，对应图3中S317-S319步骤，这里不再赘述。
S4a10，所述eNB实体接收到所述切换完成消息后，向所述MME实体发送切换到4G网络的完成消息(例如：Handover to E-UTRAN Complete)。
S4a11，所述MME实体收到来自所述eNB实体的切换到4G网络的完成消息Handover to E-UTRAN Complete后，向所述eNB实体发送承载建立请求消息(例如：Bearer Setup Request)。
S4a12，所述eNB实体接收到所述承载建立消息后，向所述终端发送无线资源控制连接重置消息(例如：RRC Connection Reconfiguration)。
S4a13，所述终端接收到所述无线资源控制连接重置消息后，向所述eNB实体发送无线资源控制连接重置完成消息(例如：RRC Connection Reconfiguration Complete)。
S4a14，所述eNB接收到所述无线资源控制连接重置完成消息后，向所述MME实体发送承载建立响应消息(例如：Bearer Setup Response消息)。
S4a15，所述MME接收所述承载建立响应消息后，向所述SGW发送承载创建响应消息(例如：Create Bearer Response)。
S4a16，所述SGW向所述PGW-C发送承载创建响应消息。
如图5a所示，假设第一制式网络为4G网络、第二制式网络为5G网络，第一核心网设备为4G网络的移动性管理实体MME，第二核心网设备为5G网络的控制面功能CP Function实体，第一接入网设备为4G网络的演进型基站eNB，第二接入网设备为5G网络的下一代无线接入网NG RAN实体，第一网关为4G网络的服务网关SGW，第二网关为4G网络的PDN网关PGW，第一策略设备为4G网络的策略与计费规则功能PCRF实体，第二策略设备为5G网络的策略功能Policy Function实体；且4G网络中的PCRF实体和5G网络中的Policy Function实体合一部署时，本发明实施例所公开的切换方法具体包括以下步骤：
1a、终端将邻居小区信号测量结果上报给NG RAN实体，NG RAN实体决定将所述终端从5G网络切换到4G网络。
S5a01，所述NG RAN实体向所述CP Function实体发送切换要求消息(例如：Handover Required)。
S5a02，所述CP Function实体接收所述切换要求消息之后，向所述MME发送第一切换请求(例如：Forward Relocation Request)。
其中，由于所述终端包括诸如数据业务等默认业务，为保持该类业务的连续性，需要为该类业务建立第一接入点名称APN，通常情况下为Default APN，对应的，所述第一切换请求中携带有：第一互联网协议IP地址，所述第一IP地址用于第一APN的建立过程。
此外，当所述终端还包括诸如VoLTE(LTE网络语音业务)、ViLTE(LTE网络视频业务)等业务时，为保持该类业务的连续性，需要为该类业务建立第二APN，通常情况下为Dedicated APN，比如IMS APN，此种情况下，所述第一切换请求还可以携带有：所述终端的第二IP地址，所述第二IP地址用于第二接入点名称APN的建立过程，其中所述第一IP地址以及所述第二IP地址是所述5G网络为所述终端分配的IP地址。
进一步地，所述第一切换请求还可能携带有以下至少一种：
所述终端的国际移动用户识别码(International Mobile Subscriber Identification Number，IMSI)、所述终端的安全上下文、所述终端的移动性管理上下文、所述终端的会话管理类上下文、所述终端在第一制式网络的终端网络能力信息。
其中，所述终端网络能力信息可通过如下两种途径获取：
途径1，所述终端在向所述CP Function实体发送的附着请求消息(例如：Attach Request)中携带所述终端网络能力信息。
途径2，所述CP Function实体向所述终端发送查询请求消息Query Request，所述终端在向所述CP Function实体发送的查询请求响应消息中携带所述终端网络能力信息。
S5a03，所述MME接收所述第一切换请求后，为所述终端在所述4G网络中发起第一接入点名称APN的建立过程。
S5a04，所述MME为所述终端在所述4G网络中发起第二接入点APN的 建立过程。
S5a05，所述MME检测到所述第一APN建立完成、所述第二APN建立完成(若存在)之后，向所述eNB发送第二切换请求(例如：Handover Request)。
S5a06，所述eNB接收所述第二切换请求后，向所述MME发送第二切换请求的响应消息(例如：Handover Request Acknowledge)。
S5a07，所述MME接收所述第二切换请求的响应消息后，向所述CP Function实体发送第一切换请求的响应消息(例如：Forward Relocation Response)，所述第一切换请求的响应消息携带所述第三IP地址。
其中，所述第一切换请求的响应消息携带有以下至少一种：
附着接受消息，所述附着接受消息携带所述第一APN的信息、所述第一IP地址、所述第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址；
分组数据网络PDN连接建立接受消息，所述PDN连接建立接受消息携带所述第二APN的信息。
S5a08，所述CP Function实体接收所述第一切换请求响应后，向所述Policy Function实体发送第七通知消息(例如：Notify7)。
其中，所述第七通知消息用于通知所述Policy Function实体如下信息：所述终端从所述5G网络切换到所述4G网络，所述第七通知消息携带所述第一IP地址、所述第三IP地址和第三使用信息，所述第三使用信息用于指示应用功能设备在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，其中所述应用功能设备应用于所述第一制式网络和所述第二制式网络。可选的，所述七通知消息还可以携带所述第二IP地址、所述第四IP地址和第四使用信息，所述第四使用信息用于指示所述应用功能设备在所述第一制式网络中使用所述第四IP地址替代所述第二IP地址。
可选地，所述CP Function实体如果与所述PGW-C实体合一部署，也就是说，所述CP Function拥有PGW-C的功能，S5a02步骤中所述第一切换请求可以不携带所述第一IP地址或者所述第二IP地址，而是直接携带所述CP Function的地址，其中所述CP Function的地址用于在步骤S5a03的所述第一 APN的建立过程中、步骤S5a04的所述第二APN的建立过程中寻址所述CP Function实体，在这种情况下，所述CP Function实体接收所述第一切换请求响应后，向所述Policy Function实体发送所述第七通知消息Notify7。
S5a09，所述Policy Function实体接收所述第七通知消息后，向所述AF设备发送第八通知消息(例如：Notify8)。
其中，所述第八通知消息用于通知所述AF设备如下信息：所述终端从所述5G网络切换到所述4G网络，所述第八通知消息携带所述第一IP地址、所述第三IP地址和第三使用信息，所述第三使用信息用于指示应用功能设备在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，其中所述应用功能设备应用于所述第一制式网络和所述第二制式网络。可选的，所述八通知消息还可以携带所述第二IP地址、所述第四IP地址和第四使用信息，所述第四使用信息用于指示所述应用功能设备在所述第一制式网络中使用所述第四IP地址替代所述第二IP地址。
S5a10，所述AF设备接收所述第八通知消息之后，使用所述第三IP地址或所述第四IP地址(若存在)与所述终端进行信令面通信，同时向接入转发网关ATGW发送更新用户面请求消息(例如：Update User Plane Request)。
其中，所述更新用户面请求消息用于请求所述ATGW将用户面的所述第一IP地址更新为所述第三IP地址，或者，用于请求所述ATGW将用户面的所述第二IP地址更新为所述第四IP地址。
S5a11，所述AF设备从所述ATGW接收更新用户面请求响应消息(例如：Update User Plane Response)。
S5a12，所述Policy Function实体接收所述第七通知消息后，发起第二承载的创建过程。
其中，S5a12的具体流程请参见图6a。
如图5b所示，假设第一制式网络为4G网络、第二制式网络为5G网络，第一核心网设备为4G网络的移动性管理实体MME，第二核心网设备为5G网络的控制面功能CP Function实体，第一接入网设备为4G网络的演进型基站eNB，第二接入网设备为5G网络的下一代无线接入网NG RAN实体，第 一网关为4G网络的服务网关SGW，第二网关为4G网络的PDN网关PGW，第一策略设备为4G网络的策略与计费规则功能PCRF实体，第二策略设备为5G网络的策略功能Policy Function实体；且4G网络中的PCRF实体和5G网络中的Policy Function实体合一部署时，本发明实施例所公开的切换方法具体包括以下步骤：
1a、终端将邻居小区信号测量结果上报给NG RAN实体，NG RAN实体决定将所述终端从5G网络切换到4G网络。
S5b01，所述NG RAN实体向所述CP Function实体发送切换要求消息(例如：Handover Required)。
S5b02，所述CP Function实体接收所述切换要求消息之后，向所述MME发送第一切换请求(例如：Forward Relocation Request)。
其中，由于所述终端包括诸如数据业务等默认业务，为保持该类业务的连续性，需要为该类业务建立第一接入点名称APN，通常情况下为Default APN，对应的，所述第一切换请求中携带有：第一互联网协议IP地址，所述第一IP地址用于第一APN的建立过程。
此外，当所述终端还包括诸如VoLTE(LTE网络语音业务)、ViLTE(LTE网络视频业务)等业务时，为保持该类业务的连续性，需要为该类业务建立第二APN，通常情况下为Dedicated APN，比如IMS APN，此种情况下，所述第一切换请求还可以携带有：所述终端的第二IP地址，所述第二IP地址用于第二接入点名称APN的建立过程，其中所述第一IP地址以及所述第二IP地址是所述5G网络为所述终端分配的IP地址。
进一步地，所述第一切换请求还可能携带有以下至少一种：
所述终端的国际移动用户识别码(International Mobile Subscriber Identification Number，IMSI)、所述终端的安全上下文、所述终端的移动性管理上下文、所述终端的会话管理类上下文、所述终端在第一制式网络的终端网络能力信息。
其中，所述终端网络能力信息可通过如下两种途径获取：
途径1，所述终端在向所述CP Function实体发送的附着请求消息(例如： Attach Request)中携带所述终端网络能力信息。
途径2，所述CP Function实体向所述终端发送查询请求消息Query Request，所述终端在向所述CP Function实体发送的查询请求响应消息中携带所述终端网络能力信息。
S5b03，所述MME接收所述第一切换请求后，为所述终端在所述4G网络中发起第一接入点名称APN的建立过程。
S5b04，所述MME为所述终端在所述4G网络中发起第二接入点APN的建立过程。
S5b05，所述MME检测到所述第一APN建立完成、所述第二APN建立完成(若存在)之后，向所述eNB发送第二切换请求(例如：Handover Request)。
S5b06，所述eNB接收所述第二切换请求后，向所述MME发送第二切换请求的响应消息(例如：Handover Request Acknowledge)。
S5b07，所述MME接收所述第二切换请求的响应消息后，向所述CP Function实体发送第一切换请求的响应消息(例如：Forward Relocation Response)，所述第一切换请求的响应消息携带所述第三IP地址。
其中，所述第一切换请求的响应消息携带有以下至少一种：
附着接受消息，所述附着接受消息携带所述第一APN的信息、所述第一IP地址、所述第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址；
分组数据网络PDN连接建立接受消息，所述PDN连接建立接受消息携带所述第二APN的信息。
S5b08，所述CP Function实体接收所述第一切换请求的响应消息后，向所述NG RAN实体发送切换要求响应消息(例如：Handover Required Response)。
其中，所述切换要求响应消息携带有以下至少一种：
附着接受消息，所述附着接受消息携带所述第一APN的信息、所述第一IP地址、所述第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址；
分组数据网络PDN连接建立接受消息，所述PDN连接建立接受消息携带所述第二APN的信息。
可选地，所述PDN连接建立接受消息还携带所述第二IP地址、所述第四IP地址和第二使用信息，所述第二使用信息用于指示所述终端在第一制式网络使用所述第四IP地址替代所述第二IP地址。
S5b09，所述NG RAN实体接收所述切换要求响应消息后，向所述终端发送切换命令消息(例如：Handover Command)。
其中，所述切换命令消息携带以下至少一项：附着接受消息、分组数据网络PDN连接建立接受消息。
其中，所述附着接受消息携带第一APN的信息、第一IP地址、第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述4G网络中使用所述第三IP地址替代所述第一IP地址，所述PDN连接建立接受消息携带所述MME为所述终端在所述4G网络建立的第二APN的信息。
可选地，所述PDN连接建立接受消息还携带所述第二IP地址、所述第四IP地址和第二使用信息，所述第二使用信息用于指示所述终端在4G网络使用所述第四IP地址替代所述第二IP地址。
S5b10，所述终端向所述eNB实体发送切换完成消息(例如：Handover Complete)。
S5b11，所述eNB实体接收到所述切换完成消息后，向所述MME实体发送切换到4G网络的完成消息(例如：Handover to E-UTRAN Complete)；
S5b12，所述MME实体收到所述切换到4G网络的完成消息后，向所述CP Function实体发送切换完成通知消息(例如：Forward Relocation Complete Notification)。
S5b13，所述CP Function实体接收到所述切换完成通知消息后，向所述MME实体发送切换完成确认消息(例如：Forward Relocation Complete Acknowledge)。
S5b14，所述CP Function实体发送所述切换完成确认消息后，向所述Policy Function实体发送第九通知消息(例如：Notify9)。
其中，所述第九通知消息用于通知所述Policy Function实体如下信息：所述终端从所述5G网络切换到所述4G网络，所述第九通知消息携带所述第一IP地址、所述第三IP地址和第三使用信息，所述第三使用信息用于指示应用功能设备在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，其中所述应用功能设备应用于第一制式网络和第二制式网络。可选的，所述九通知消息还可以携带所述第二IP地址、所述第四IP地址和第四使用信息，所述第四使用信息用于指示所述应用功能设备在所述第一制式网络中使用所述第四IP地址替代所述第二IP地址。
可选地，所述CP Function实体如果与所述PGW-C实体合一部署，也就是说，所述CP Function拥有PGW-C的功能，S5b02步骤中所述第一切换请求可以不携带所述第一IP地址或者所述第二IP地址，而是直接携带所述CP Function的地址，其中所述CP Function的地址用于在步骤S5a03的所述第一APN的建立过程中、步骤S5a04的所述第二APN的建立过程中寻址所述CP Function实体，在这种情况下，所述CP Function实体发送所述切换完成确认消息后，向所述Policy Function实体发送所述第九通知消息Notify9。
S5b15，所述Policy Function实体接收所述第九通知消息后，向所述AF设备发送第十通知消息(例如：Notify10)。
其中，所述第十通知消息用于通知所述AF设备如下信息：所述终端从所述5G网络切换到所述4G网络，所述第十通知消息携带所述第一IP地址、所述第三IP地址和第三使用信息，所述第三使用信息用于指示应用功能设备在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，其中所述应用功能设备应用于第一制式网络和第二制式网络。可选的，所述十通知消息还可以携带所述第二IP地址、所述第四IP地址和第四使用信息，所述第四使用信息用于指示所述应用功能设备在所述第一制式网络中使用所述第四IP地址替代所述第二IP地址。
S5b16，所述AF设备接收所述第十通知消息之后，使用所述第三IP地址或所述第四IP地址(若存在)与所述终端进行信令面通信，同时向接入转发网关ATGW发送更新用户面请求消息(例如：Update User Plane Request)。
其中，所述更新用户面请求消息用于请求所述ATGW将用户面的所述第一IP地址更新为所述第三IP地址，或者，用于请求所述ATGW将用户面的所述第二IP地址更新为所述第四IP地址。
S5a17，所述AF设备从所述ATGW接收更新用户面请求响应消息(例如：Update User Plane Response)。
S5b18，所述Policy Function实体接收所述第九通知消息后，发起第二承载的创建过程。
其中，S5b18的具体流程请参见图6b。
进一步地，请参阅图6a，图6a是图5a中所描述的步骤5a12中专有第二承载的创建过程的一种可能的实现方式，该针对第二IP地址的第二承载建立过程，与第一IP地址的第一承载的建立过程相同，以下以第二IP地址为例，说明第二承载的建立具体过程，具体包括以下步骤：
1a，所述Policy Function实体为终端发起第二承载的建立过程之前，从AF设备接收业务建立请求消息，也就是第一承载的建立请求，所述业务建立请求消息中携带业务要求信息；
其中，所述第一承载为所述终端的所述业务在所述5G网络中建立的承载，当所述终端从所述5G网络切换到所述4G网络，为保持所述业务连续性，所述4G网络为所述终端的所述业务时建立了第二承载，1a步骤主要是为了保证在第一承载建立过程中，所述Policy Function实体从所述AF实体接收所述业务要求信息，保证所述4G网络中的PCRF实体和所述5G网络中的Policy Function实体合一部署时，所述Policy Function实体可以使用所述业务要求信息为所述终端的所述业务直接发起所述第二承载的建立过程。
S6a01，所述Policy Function实体通过5G网络的第一IP地址查找到业务要求信息，并通过4G网络的第三IP地址寻址到所述PGW，并向所述PGW发送重新认证请求消息。
S6a02，所述PGW接收所述重新认证请求消息后，向所述PCRF实体发送重新认证应答消息。
S6a03，所述PGW向所述SGW发送承载创建请求消息(例如：Create  Bearer Request)。
S6a04，所述SGW向所述MME转发所述承载创建请求消息。
S6a05-S6a07，对应图5中S517-S519步骤，这里不再赘述。
S6a08，所述eNB实体接收到所述切换完成消息后，向所述MME实体发送切换到4G网络的完成消息(例如：Handover to E-UTRAN Complete)。
S6a09，所述MME实体收到来自所述eNB实体的切换到4G网络的完成消息Handover to E-UTRAN Complete后，向所述eNB实体发送承载建立请求消息(例如：Bearer Setup Request)。
S6a10，所述eNB实体接收到所述承载建立消息后，向所述终端发送无线资源控制连接重置消息(例如：RRC Connection Reconfiguration)。
S6a11，所述终端接收到所述无线资源控制连接重置消息后，向所述eNB实体发送无线资源控制连接重置完成消息(例如：RRC Connection Reconfiguration Complete)。
S6a12，所述eNB接收到所述无线资源控制连接重置完成消息后，向所述MME实体发送承载建立响应消息消息(例如：Bearer Setup Response)。
S6a13，所述MME接收所述承载建立响应消息后，向所述SGW发送承载创建响应消息(例如：Create Bearer Response)。
S6a14，所述SGW向所述PGW-C发送承载创建响应消息。
进一步地，请参阅图6b，图6b是图5b中所描述的步骤5b18专有第二承载的创建过程的一种可能的实现方式，该针对第二IP地址的第二承载建立过程，与第一IP地址的第一承载的建立过程相同，以下以第二IP地址为例，说明第二承载的建立具体过程，具体包括以下步骤：
1a，所述Policy Function实体为终端发起第二承载的建立过程之前，从AF设备接收业务建立请求消息，也就是第一承载的建立请求，所述业务建立请求消息中携带业务要求信息；
其中，所述第一承载为所述终端的所述业务在所述5G网络中建立的承载，当所述终端从所述5G网络切换到所述4G网络，为保持所述业务连续性，所述4G网络为所述终端的所述业务时建立了第二承载，1a步骤主要是为了保 证在第一承载建立过程中，所述Policy Function实体从所述AF实体接收所述业务要求信息，保证所述4G网络中的PCRF实体和所述5G网络中的Policy Function实体合一部署时，所述Policy Function实体可以使用所述业务要求信息为所述终端的所述业务直接发起所述第二承载的建立过程。
S6b01，所述Policy Function实体通过5G网络的第一IP地址查找到业务要求信息，并通过4G网络的第三IP地址寻址到所述PGW，并向所述PGW发送重新认证请求消息。
S6b02，所述PGW接收所述重新认证请求消息后，向所述PCRF实体发送重新认证应答消息。
S6b03，所述PGW向所述SGW发送承载创建请求消息(例如：Create Bearer Request)。
S6b04，所述SGW向所述MME转发所述承载创建请求消息。
S6b05，所述MME实体向所述eNB实体发送承载建立请求消息(例如：Bearer Setup Request)。
S6b06，所述eNB实体接收到所述承载建立消息后，向所述终端发送无线资源控制连接重置消息(例如：RRC Connection Reconfiguration)。
S6b07，所述终端接收到所述无线资源控制连接重置消息后，向所述eNB实体发送无线资源控制连接重置完成消息(例如：RRC Connection Reconfiguration Complete)。
S6b08，所述eNB接收到所述无线资源控制连接重置完成消息后，向所述MME实体发送承载建立响应消息消息(例如：Bearer Setup Response)。
S6b09，所述MME接收所述承载建立响应消息后，向所述SGW发送承载创建响应消息(例如：Create Bearer Response)。
S6b10，所述SGW向所述PGW-C发送承载创建响应消息。
与上述图3至图7所示的实施例一致的，请参阅图7，图7是本发明实施例提供的第一APN的建立过程的一种可能的实现方式，如图所示，第一APN的建立过程具体包括以下步骤。
S701，所述MME向归属用户服务器HSS发送位置更新请求消息(例如： Update Location Request)。
S702，所述HSS接收所述位置更新请求消息后，向所述MME发送位置更新确认消息(例如：Update Location Response)。
其中，上述步骤S701和步骤S702为可选的步骤。
S703，所述MME接收所述位置更新确认消息后，基于5G网络的第一互联网协议IP地址为所述终端发起第一接入点名称APN的建立过程，向所述SGW发送第一创建会话请求(例如：Create Session Request1)。
S704，所述SGW接收所述第一创建会话请求后，向所述PGW发送第三创建会话请求(例如：Create Session Request3)。
S705，所述PGW接收所述第三创建会话请求后，为所述终端在4G网络中分配第三IP地址，然后向所述PCRF实体发送第一信用控制请求消息CCR1，请求为所述第三IP地址建立IP连通性接入网会话。
S706，所述PCRF实体接收所述CCR1后，向所述PGW发送第一信用控制应答消息(例如：CCA1)。
S707，所述PGW接收所述第一信用控制应答消息后，向所述SGW发送第三创建会话响应(例如：Create Session Response3)。
其中，所述第三创建会话响应包括所述第三IP地址，所述第三创建会话响应携带有指示所述终端使用所述第三IP地址的信息。
S708，所述SGW接收所述第三创建会话响应后，向所述MME发送第一创建会话响应(例如：Create Session Response1)。
其中，所述第一创建会话响应包括所述第三IP地址，所述第一创建会话响应携带有指示所述终端使用所述第三IP地址的信息。
与上述图3至图6所示的实施例一致的，请参阅图8，图8是本发明实施例提供的第二APN的建立过程的一种可能的实现方式，如图所示，第二APN的建立过程具体包括以下步骤。
S801，所述MME基于所述第二IP地址为所述终端发起第二APN的建立过程，向所述SGW发送第二创建会话请求(例如：Create Session Request2)。
S802，所述SGW接收所述第二创建会话请求后，向所述PGW发送第四 创建会话请求(例如：Create Session Request4)。
S803，所述PGW接收所述第四创建会话请求后，为所述终端在4G网络中分配第四IP地址，然后向所述PCRF发送第二信用控制请求消息(例如：CCR2)，请求为所述第四IP地址建立IP连通性接入网会话。
S804，所述PCRF实体接收所述第二信用控制请求消息后，向所述PGW发送第二信用控制应答消息(例如：CCA2)。
S805，所述PGW接收所述第二信用控制应答消息后，向所述SGW发送第四创建会话响应(例如：Create Session Response4)。
其中，所述第四创建会话响应包括所述第四IP地址，所述第四创建会话响应携带有指示所述终端使用所述第四IP地址的信息。
S806，所述SGW接收所述第四创建会话响应后，向所述MME发送第二创建会话响应(例如：Create Session Response2)。
其中，所述第二创建会话响应包括所述第四IP地址，所述第二创建会话响应携带有所述指示所述终端使用所述第四IP地址的信息。
上述主要从各个网元之间交互的角度对本发明实施例的方案进行了介绍。可以理解的是，各个网元，例如第一核心网设备、第二核心网设备、第二接入网设备、终端等为了实现上述功能，其包含了执行各个功能相应的硬件结构和/或软件模块。本领域技术人员应该很容易意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，本发明能够以硬件或硬件和计算机软件的结合形式来实现。某个功能究竟以硬件还是计算机软件驱动硬件的方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对每个特定的应用使用不同方法来实现所描述的功能，但是这种实现不应认为超出本发明的范围。
本发明实施例可以根据上述方法示例对第一核心网设备、第一核心网设备、第二接入网设备、终端等进行功能单元的划分，例如，可以对应各个功能划分各个功能单元，也可以将两个或两个以上的功能集成在一个处理单元中。上述集成的单元既可以采用硬件的形式实现，也可以采用软件功能单元的形式实现。需要说明的是，本发明实施例中对单元的划分是示意性的，仅仅为一种 逻辑功能划分，实际实现时可以有另外的划分方式。
在采用集成的单元的情况下，图9A示出了上述实施例中所涉及的第一核心网设备的一种可能的结构示意图。第一核心网设备900包括：处理单元902和通信单元903。处理单元902用于对第一核心网设备的动作进行控制管理，例如，处理单元902用于支持第一核心网设备执行图2中的203、204、205、206，图3中的步骤S303、S304、S307、S308、S314、S316，图4中的步骤S407，图5中的步骤S503、S504、S507、S508、S514、S516，图6中的S605，图7中的步骤S701、S703，图8中的S801，图3a中的步骤S3a03、S3a04、S3a05、S3a07，图3b中的步骤S3b03、S3b04、S3b05、S3b07、S3b12，图3c中的步骤S3b03、S3b04、S3b05、S3b07，图3d中的步骤S3d03、S3d04、S3d05、S3d07，图4a中的步骤S4a07、S4a07、S4a11、S4a15，图5a中的步骤S5a03、S5a04、S5a05、S5a07，图5b中的步骤S5b03、S5b04、S5b05、S5b07、S5b12，图6a中的步骤S6a05、S6a13，图6b中的步骤S6b05、S6b09和/或用于本文所描述的技术的其它过程。通信单元903用于支持第一核心网设备与其他网络实体的通信，例如与图1中示出的eNB、SGW等之间的通信。第一核心网设备还可以包括存储单元901，用于存储MME的程序代码和数据。
其中，处理单元902可以是处理器或控制器，例如可以是中央处理器(Central Processing Unit，CPU)，通用处理器，数字信号处理器(Digital Signal Processor，DSP)，专用集成电路(Application-Specific Integrated Circuit，ASIC)，现场可编程门阵列(Field Programmable Gate Array，FPGA)或者其他可编程逻辑器件、晶体管逻辑器件、硬件部件或者其任意组合。其可以实现或执行结合本发明公开内容所描述的各种示例性的逻辑方框，模块和电路。所述处理器也可以是实现计算功能的组合，例如包含一个或多个微处理器组合，DSP和微处理器的组合等等。通信单元903可以是通信接口、收发器、收发电路等，其中，通信接口是统称，可以包括一个或多个接口，例如可以包括：MME和SGW之间的接口，MME与eNB之间的接口和/或其他接口。存储单元901可以是存储器。
当处理单元902为处理器，通信单元903为通信接口，存储单元901为 存储器时，本发明实施例所涉及的MME可以为图9B所示的MME。
参阅图9B所示，该第一核心网设备910包括：处理器912、通信接口913、存储器911。可选的，第一核心网设备910还可以包括总线914。其中，通信接口913、处理器912以及存储器911可以通过总线914相互连接；总线914可以是外设部件互连标准(Peripheral Component Interconnect，简称PCI)总线或扩展工业标准结构(Extended Industry Standard Architecture，简称EISA)总线等。所述总线914可以分为地址总线、数据总线、控制总线等。为便于表示，图9B中仅用一条粗线表示，但并不表示仅有一根总线或一种类型的总线。
上述图9A或图9B所示的第一核心网设备也可以理解为一种用于第一核心网设备的装置，本发明实施例不限定。
在采用集成的单元的情况下，图10A示出了上述实施例中所涉及的第二核心网设备的一种可能的结构示意图。第二核心网设备1000包括：处理单元1002和通信单元1003。处理单元1002用于对第二核心网设备的动作进行控制管理，例如，处理单元1002用于支持第二核心网设备执行图2中的202、207，图3中的步骤S302、S305、S309、S317，图5中的步骤S502、S505、S509、S517，图3a中的步骤S3a02、S3a08，图3b中的步骤S3b02、S3b08、S3b13、S3b14，图3c中的步骤S3c02、S3c08，图3d中的步骤S3d02、S3d08，图5a中的步骤S5a02、S5a08，图5b中的步骤S5b02、S5b08、S5b13、S5b14和/或用于本文所描述的技术的其它过程。通信单元1003用于支持第二核心网设备与其他网络实体的通信，例如与图1中示出的NG RAN实体、UP Function实体等之间的通信。第二核心网设备还可以包括存储单元1001，用于存储第二核心网设备的程序代码和数据。
其中，处理单元1002可以是处理器或控制器，例如可以是中央处理器(Central Processing Unit，CPU)，通用处理器，数字信号处理器(Digital Signal Processor，DSP)，专用集成电路(Application-Specific Integrated Circuit，ASIC)，现场可编程门阵列(Field Programmable Gate Array，FPGA)或者其他可编程逻辑器件、晶体管逻辑器件、硬件部件或者其任意组合。其可以实现或执行结合本发明公开内容所描述的各种示例性的逻辑方框，模块和电路。所述处理器 也可以是实现计算功能的组合，例如包含一个或多个微处理器组合，DSP和微处理器的组合等等。通信单元1003可以是通信接口、收发器、收发电路等，其中，通信接口是统称，可以包括一个或多个接口，例如可以包括：CP Function实体和NG RAN实体之间的接口，CP Function实体与UP Function实体之间的接口和/或其他接口。存储单元1001可以是存储器。
当处理单元1002为处理器，通信单元1003为通信接口，存储单元1001为存储器时，本发明实施例所涉及的第二核心网设备可以为图10B所示的第二核心网设备。
参阅图10B所示，该第二核心网设备1010包括：处理器1010、通信接口1013、存储器1011。可选的，第二核心网设备1010还可以包括总线1014。其中，通信接口1013、处理器1010以及存储器1011可以通过总线1014相互连接；总线1014可以是外设部件互连标准(Peripheral Component Interconnect，简称PCI)总线或扩展工业标准结构(Extended Industry Standard Architecture，简称EISA)总线等。所述总线1014可以分为地址总线、数据总线、控制总线等。为便于表示，图10B中仅用一条粗线表示，但并不表示仅有一根总线或一种类型的总线。
上述图10A或图10B所示的第二核心网设备也可以理解为一种用于CP Function实体的装置，本发明实施例不限定。
在采用集成的单元的情况下，图11A示出了上述实施例中所涉及的第二接入网设备的一种可能的结构示意图。第二接入网设备1100包括：处理单元1102、第一通信单元1103和第二通信单元1104。处理单元1102用于对第二接入网设备的动作进行控制管理，例如，处理单元1102用于支持第二接入网设备执行图2中的步骤201、207、208和/或用于本文所描述的技术的其它过程。第一通信单元1103用于支持第二接入网设备1100与其他接入网设备或核心网设备之间的通信。第二通信单元1104用于支持第二接入网设备与终端之间的通信。第二接入网设备还可以包括存储单元1101，用于存储第二接入网设备的程序代码和数据。
其中，处理单元1102可以是处理器或控制器，例如可以是中央处理器 (Central Processing Unit，CPU)，通用处理器，数字信号处理器(Digital Signal Processor，DSP)，专用集成电路(Application-Specific Integrated Circuit，ASIC)，现场可编程门阵列(Field Programmable Gate Array，FPGA)或者其他可编程逻辑器件、晶体管逻辑器件、硬件部件或者其任意组合。其可以实现或执行结合本发明公开内容所描述的各种示例性的逻辑方框，模块和电路。所述处理器也可以是实现计算功能的组合，例如包含一个或多个微处理器组合，DSP和微处理器的组合等等。第一通信单元1103可以是通信接口，其中，该通信接口是统称，在具体实现中，该通信接口可以包括多个接口，例如可以包括：接入网设备与接入网设备之间的接口、接入网设备与核心网设备之间的接口和/或其他接口。第二通信单元1104可以是收发器或收发电路等。存储单元1101可以是存储器。
当处理单元1102为处理器，第一通信单元1103为通信接口，第二通信单元1104为收发器，存储单元1101为存储器时，本发明实施例所涉及的第二接入网设备可以为图11B所示的第二接入网设备。
参阅图11B所示，该第二接入网设备1110包括：处理器1112、通信接口1113、收发器1114、存储器1111。可选的，第二接入网设备1110还可以包括总线1115。其中，通信接口1113、收发器1114、处理器1112以及存储器1111可以通过总线1115相互连接；总线1115可以是外设部件互连标准(Peripheral Component Interconnect，简称PCI)总线或扩展工业标准结构(Extended Industry Standard Architecture，简称EISA)总线等。所述总线1115可以分为地址总线、数据总线、控制总线等。为便于表示，图11B中仅用一条粗线表示，但并不表示仅有一根总线或一种类型的总线。
上述图11A或图11B所示的第二接入网设备也可以理解为一种用于NG RAN实体的装置，本发明实施例不限定。
在采用集成的单元的情况下，图12A示出了上述实施例中所涉及的终端的一种可能的结构示意图。终端1200包括：处理单元1202和通信单元1203。处理单元1202用于对终端的动作进行控制管理，例如，处理单元1202用于支持终端执行图2中的步骤209和210和/或用于本文所描述的技术的其它过程。 通信单元1203用于支持终端与其他网络实体的通信，例如与图1中示出的NG RAN实体等之间的通信。终端还可以包括存储单元1201，用于存储终端的程序代码和数据。
其中，处理单元1202可以是处理器或控制器，例如可以是中央处理器(Central Processing Unit，CPU)，通用处理器，数字信号处理器(Digital Signal Processor，DSP)，专用集成电路(Application-Specific Integrated Circuit，ASIC)，现场可编程门阵列(Field Programmable Gate Array，FPGA)或者其他可编程逻辑器件、晶体管逻辑器件、硬件部件或者其任意组合。其可以实现或执行结合本发明公开内容所描述的各种示例性的逻辑方框，模块和电路。所述处理器也可以是实现计算功能的组合，例如包含一个或多个微处理器组合，DSP和微处理器的组合等等。通信单元1203可以是收发器、收发电路或通信即可欧等，其中，通信接口是统称，可以包括一个或多个接口。存储单元1201可以是存储器。
当处理单元1202为处理器，通信单元1203为收发器，存储单元1201为存储器时，本发明实施例所涉及的终端可以为图12B所示的终端。
参阅图12B所示，该终端1210包括：处理器1212、收发器1213、存储器1211。可选的，终端1210还可以包括总线1214。其中，收发器1213、处理器1212以及存储器1211可以通过总线1214相互连接；总线1214可以是外设部件互连标准(Peripheral Component Interconnect，简称PCI)总线或扩展工业标准结构(Extended Industry Standard Architecture，简称EISA)总线等。所述总线1214可以分为地址总线、数据总线、控制总线等。为便于表示，图12B中仅用一条粗线表示，但并不表示仅有一根总线或一种类型的总线。
上述图12A或图12B所示的终端也可以理解为一种用于终端的装置，本发明实施例不限定。
此外，本发明实施例也提供如下网元的装置：第一网关、第二网关、第一接入网设备、第一策略设备、第二策略设备、应用功能设备等，这些网元的结构示意图类似于上述第一核心网设备或上述第二核心网设备或终端或第二接入网设备的结构示意图，本发明实施例不作赘述。
本发明实施例所描述的方法或者算法的步骤可以以硬件的方式来实现，也可以是由处理器执行软件指令的方式来实现。软件指令可以由相应的软件模块组成，软件模块可以被存放于随机存取存储器(Random Access Memory，RAM)、闪存、只读存储器(Read Only Memory，ROM)、可擦除可编程只读存储器(Erasable Programmable ROM，EPROM)、电可擦可编程只读存储器(Electrically EPROM，EEPROM)、寄存器、硬盘、移动硬盘、只读光盘(CD-ROM)或者本领域熟知的任何其它形式的存储介质中。一种示例性的存储介质耦合至处理器，从而使处理器能够从该存储介质读取信息，且可向该存储介质写入信息。当然，存储介质也可以是处理器的组成部分。处理器和存储介质可以位于ASIC中。另外，该ASIC可以位于网关设备或移动性管理网元中。当然，处理器和存储介质也可以作为分立组件存在于网关设备或移动性管理网元中。
本领域技术人员应该可以意识到，在上述一个或多个示例中，本发明实施例所描述的功能可以用硬件、软件、固件或它们的任意组合来实现。当使用软件实现时，可以将这些功能存储在计算机可读介质中或者作为计算机可读介质上的一个或多个指令或代码进行传输。计算机可读介质包括计算机存储介质和通信介质，其中通信介质包括便于从一个地方向另一个地方传送计算机程序的任何介质。存储介质可以是通用或专用计算机能够存取的任何可用介质。
以上所述的具体实施方式，对本发明实施例的目的、技术方案和有益效果进行了进一步详细说明，所应理解的是，以上所述仅为本发明实施例的具体实施方式而已，并不用于限定本发明实施例的保护范围，凡在本发明实施例的技术方案的基础之上，所做的任何修改、等同替换、改进等，均应包括在本发明实施例的保护范围之内。

Claims (40)

  1. 一种切换方法，其特征在于，包括：
    第一核心网设备从第二核心网设备接收第一切换请求，所述第一切换请求携带第一互联网协议IP地址，所述第一IP地址用于第一接入点名称APN的建立过程，其中，所述第一核心网设备应用于第一制式网络，所述第二核心网设备应用于第二制式网络，所述第一IP地址为所述第二制式网络为终端分配的IP地址；
    所述第一核心网设备为所述终端在所述第一制式网络中发起所述第一APN的建立过程；其中，所述第一核心网设备为所述终端在所述第一制式网络发起所述第一APN的建立过程，包括：所述第一核心网设备基于所述第一IP地址向第一网关发送第一创建会话请求；所述第一核心网设备从所述第一网关接收第一创建会话响应，所述第一创建会话响应携带所述第一制式网络为所述终端分配的第三IP地址，所述第一创建会话响应用于指示所述终端使用所述第三IP地址；
    所述第一核心网设备向接入网设备发送第二切换请求，其中，所述接入网设备应用于所述第一制式网络；
    所述第一核心网设备从所述接入网设备接收所述第二切换请求的响应消息；
    所述第一核心网设备向所述第二核心网设备发送所述第一切换请求的响应消息，所述第一切换请求的响应消息携带所述第三IP地址。
  2. 根据权利要求1所述的方法，其特征在于，所述第一切换请求还携带指示信息，所述指示信息用于指示所述第一核心网设备在完成所述第一APN的建立过程之后向所述第二核心网设备发送第一通知消息，所述方法还包括：
    所述第一核心网设备向所述第二核心网设备发送所述第一通知消息，所述第一通知消息用于通知所述第二核心网设备：所述第一核心网设备基于所述第一IP地址为所述终端建立了所述第一APN，所述第一通知消息中携带所述第一IP地址和所述第三IP地址。
  3. 根据权利要求2中所述的方法，其特征在于，所述第一核心网设备向 所述接入网设备发送第二切换请求之前，所述方法还包括：
    所述第一核心网设备从所述第一网关接收承载创建请求消息；
    所述第一核心网设备向所述第一网关发送承载创建响应消息。
  4. 根据权利要求1至3中任一项所述的方法，其特征在于，所述第一核心网设备为所述终端在所述第一制式网络中发起所述第一APN的建立过程之后，所述方法还包括：
    所述第一核心网设备为所述终端在所述第一制式网络中发起第二APN的建立过程。
  5. 根据权利要求4所述的方法，其特征在于，所述第一切换请求还携带第二IP地址，其中，所述第二IP地址为所述第二制式网络为所述终端分配的IP地址，所述第一核心网设备为所述终端在所述第一制式网络中发起第二APN的建立过程，包括：
    所述第一核心网设备向所述第一网关发送第二创建会话请求；
    所述第一核心网设备从所述第一网关接收第二创建会话响应，所述第二创建会话响应携带所述第一制式网络为所述终端分配的第四IP地址，所述第二创建会话响应用于指示所述终端使用所述第四IP地址。
  6. 根据权利要求4或5所述的方法，其特征在于，所述第一切换请求的响应消息携带以下至少一项：
    附着接受消息，所述附着接受消息携带所述第一APN的信息、所述第一IP地址、所述第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址；
    分组数据网络PDN连接建立接受消息，所述PDN连接建立接受消息携带所述第二APN的信息；或者，
    会话管理SM请求消息，所述SM请求消息携带所述终端在所述第一制式网络的承载信息。
  7. 根据权利要求1至6任一项所述的方法，其特征在于，所述第一核心网设备向所述第二核心网设备发送第一切换请求的响应消息之后，所述方法还包括：
    所述第一核心网设备从所述第一网关接收承载创建请求消息；
    所述第一核心网设备从所述接入网设备接收切换到第一制式网络的完成消息；
    所述第一核心网设备向所述接入网设备发送承载建立请求消息；
    所述第一核心网设备从所述接入网设备接收承载建立响应消息；
    所述第一核心网设备向所述第一网关发送承载创建响应消息。
  8. 根据权利要求7所述的方法，其特征在于，所述第一核心网设备从所述接入网设备接收切换到第一制式网络的完成消息之后，所述方法还包括：
    所述第一核心网设备向所述第二核心网设备发送切换完成通知消息；
    所述第一核心网设备从所述第二核心网设备接收切换完成确认消息。
  9. 一种切换方法，其特征在于，包括：
    第二核心网设备从接入网设备接收切换要求消息，其中，所述第二核心网设备和所述接入网设备应用于第二制式网络；
    所述第二核心网设备向第一核心网设备发送第一切换请求，所述第一切换请求携带第一互联网协议IP地址，所述第一IP地址用于终端在第一制式网络的第一接入点名称APN的建立过程，其中，所述第一核心网设备应用于所述第一制式网络，所述第一IP地址为所述第二制式网络为所述终端分配的IP地址；
    所述第二核心网设备从所述第一核心网设备接收所述第一切换请求的响应消息，所述第一切换请求的响应消息携带第三IP地址，所述第三IP地址为所述第一制式网络在所述第一APN的建立过程中为所述终端分配的IP地址；
    所述第二核心网设备向所述接入网设备发送切换要求响应消息。
  10. 根据权利要求9所述的方法，其特征在于，所述第一切换请求还携带指示信息，所述指示信息用于指示所述第一核心网设备在完成所述第一APN的建立过程之后向所述第二核心网设备发送第一通知消息，所述方法还包括：
    所述第二核心网设备从所述第一核心网设备接收所述第一通知消息，所述第一通知消息用于通知所述第二核心网设备：所述第一核心网设备基于所述 第一IP地址为所述终端建立了所述第一APN，所述第一通知消息中携带所述第一IP地址和所述第三IP地址。
  11. 根据权利要求10所述的方法，其特征在于，所述第二核心网设备从所述第一核心网设备接收所述第一通知消息之后，所述方法还包括：
    所述第二核心网设备向第二策略设备发送第三通知消息，所述第三通知消息用于通知所述第二策略设备：所述第一核心网设备基于所述第一IP地址为所述终端建立了所述第一APN，其中，所述第二策略设备应用于所述第二制式网络，所述第三通知消息中携带所述第三IP地址。
  12. 根据权利要求9至11中任一项所述的方法，其特征在于，所述第一切换请求还携带第二IP地址，所述第二IP地址用于所述终端在所述第一制式网络的第二APN的建立过程，其中，所述第二IP地址为所述第二制式网络为所述终端分配的IP地址。
  13. 根据权利要求12所述的方法，其特征在于，所述第一切换请求的响应消息携带以下至少一项：
    附着接受消息，所述附着接受消息携带所述第一APN的信息、所述第一IP地址、所述第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址；
    分组数据网络PDN连接建立接受消息，所述PDN连接建立接受消息携带所述第二APN的信息；或者，
    会话管理SM请求消息，所述SM请求消息携带所述终端在所述第一制式网络的承载信息。
  14. 根据权利要求13所述的方法，其特征在于，所述切换要求响应消息携带以下至少一项：所述附着接受消息、所述PDN连接建立接受消息或所述SM请求消息。
  15. 根据权利要求9至14任一项所述的方法，所述第二核心网设备从所述第一核心网设备接收第一切换请求的响应消息之后，所述方法还包括：
    所述第二核心网设备向所述第二策略设备发送第七通知消息，所述第七通知消息用于通知所述第二策略设备：所述终端从所述第二制式网络切换到所 述第一制式网络。
  16. 根据权利要求15所述的方法，其特征在于，
    所述第七通知消息携带所述第一IP地址、所述第三IP地址和第三使用信息，所述第三使用信息用于指示应用功能设备在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，其中所述应用功能设备应用于所述第一制式网络和所述第二制式网络。
  17. 根据权利要求9至14任一项所述的方法，所述第二核心网设备从所述第一核心网设备接收第一切换请求的响应消息之后，所述方法还包括：
    所述第二核心网设备向所述第一核心网设备发送切换完成确认消息；
    所述第二核心网设备向所述第二策略设备发送第九通知消息，所述第九通知消息用于通知所述第二策略设备：所述终端从所述第二制式网络切换到所述第一制式网络。
  18. 根据权利要求17所述的方法，其特征在于，
    所述第九通知消息携带所述第一IP地址、所述第三IP地址和第三使用信息，所述第三使用信息用于指示应用功能设备在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，其中所述应用功能设备应用于所述第一制式网络和所述第二制式网络。
  19. 一种切换方法，其特征在于，包括：
    第二接入网设备向第二核心网设备发送切换要求消息，所述切换要求消息用于请求将终端从第二制式网络切换到第一制式网络，其中，所述第二接入网设备和所述第二核心网设备应用于所述第二制式网络；
    所述第二接入网设备从所述第二核心网设备接收切换要求响应消息，所述切换要求响应消息携带以下至少一项：附着接受消息、分组数据网络PDN连接建立接受消息或会话管理SM请求消息，其中，所述附着接受消息携带第一核心网设备为所述终端在所述第一制式网络建立的第一接入点名称APN的信息、所述第二制式网络为所述终端分配的第一互联网协议IP地址、所述第一制式网络在所述第一APN的建立过程中为所述终端分配的第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用 所述第三IP地址替代所述第一IP地址，所述PDN连接建立接受消息携带所述第一核心网设备为所述终端在所述第一制式网络建立的第二APN的信息，所述SM请求消息携带所述终端在所述第一制式网络的承载信息；
    所述第二接入网设备向所述终端发送切换命令消息，所述切换命令消息携带以下至少一项：所述附着接受消息、所述PDN连接建立接受消息或所述SM请求消息。
  20. 一种切换方法，其特征在于，包括：
    终端从第二接入网设备接收切换命令消息，所述切换命令消息携带以下至少一项：附着接受消息、分组数据网络PDN连接建立接受消息或会话管理SM请求消息，其中，所述附着接受消息携带第一核心网设备为所述终端在所述第一制式网络建立的第一接入点名称APN的信息、所述第二制式网络为所述终端分配的第一互联网协议IP地址、所述第一制式网络在所述第一APN的建立过程中为所述终端分配的第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，所述PDN连接建立接受消息携带所述第一核心网设备为所述终端在所述第一制式网络建立的第二APN的信息，所述SM请求消息携带所述终端在所述第一制式网络的承载信息；其中，所述第二接入网设备应用于所述第二制式网络；
    所述终端根据所述附着接受消息、所述PDN连接建立接受消息或所述SM请求消息中的至少一项接入所述第一制式网络；
    所述终端向第一接入网设备发送切换完成消息，所述第一接入网设备应用于所述第一制式网络。
  21. 一种第一核心网设备，其特征在于，包括：处理单元和通信单元，
    所述处理单元用于通过所述通信单元从第二核心网设备接收第一切换请求，所述第一切换请求携带第一互联网协议IP地址，所述第一IP地址用于第一接入点名称APN的建立过程，其中，所述第一核心网设备应用于第一制式网络，所述第二核心网设备应用于第二制式网络，所述第一IP地址为所述第二制式网络为终端分配的IP地址；以及用于为所述终端在所述第一制式网络 中发起所述第一APN的建立过程，其中，在所述为所述终端在所述第一制式网络发起所述第一APN的建立过程中，所述处理单元具体用于：基于所述第一IP地址通过所述通信单元向第一网关发送第一创建会话请求，以及通过所述通信单元从所述第一网关接收第一创建会话响应，所述第一创建会话响应携带所述第一制式网络为所述终端分配的第三地址，所述第一创建会话响应用于指示所述终端使用所述第三IP地址；以及用于通过所述通信单元向接入网设备发送第二切换请求，其中，所述接入网设备应用于所述第一制式网络；以及用于通过所述通信单元从所述接入网设备接收所述第二切换请求的响应消息；以及用于通过所述通信单元向所述第二核心网设备发送所述第一切换请求的响应消息，所述第一切换请求的响应消息携带所述第三IP地址。
  22. 根据权利要求21所述的第一核心网设备，其特征在于，所述第一切换请求还携带指示信息，所述指示信息用于指示所述第一核心网设备在完成所述第一APN的建立过程之后向所述第二核心网设备发送第一通知消息，所述处理单元还用于通过所述通信单元向所述第二核心网设备发送所述第一通知消息，所述第一通知消息用于通知所述第二核心网设备：所述第一核心网设备基于所述第一IP地址为所述终端建立了所述第一APN，所述第一通知消息中携带所述第一IP地址和所述第三IP地址。
  23. 根据权利要求22中所述的第一核心网设备，其特征在于，所述处理单元在通过所述通信单元向所述接入网设备发送第二切换请求之前，还用于通过所述通信单元从所述第一网关接收承载创建请求消息；以及用于通过所述通信单元向所述第一网关发送承载创建响应消息。
  24. 根据权利要求21至23中任一项所述的第一核心网设备，其特征在于，所述处理单元为所述终端在所述第一制式网络中发起所述第一APN的建立过程之后，还用于为所述终端在所述第一制式网络中发起第二APN的建立过程。
  25. 根据权利要求24所述的方法，其特征在于，所述第一切换请求还携带第二IP地址，其中，所述第二IP地址为所述第二制式网络为所述终端分配的IP地址，在所述为所述终端在所述第一制式网络中发起第二APN的建立过 程中，所述处理单元具体用于：通过所述通信单元向所述第一网关发送第二创建会话请求；以及用于通过所述通信单元从所述第一网关接收第二创建会话响应，所述第二创建会话响应携带所述第一制式网络为所述终端分配的第四IP地址，所述第二创建会话响应用于指示所述终端使用所述第四IP地址。
  26. 根据权利要求24或25所述的第一核心网设备，其特征在于，所述第一切换请求的响应消息携带以下至少一项：
    附着接受消息，所述附着接受消息携带所述第一APN的信息、所述第一IP地址、所述第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址；
    分组数据网络PDN连接建立接受消息，所述PDN连接建立接受消息携带所述第二APN的信息；或者，
    会话管理SM请求消息，所述SM请求消息携带所述终端在所述第一制式网络的承载信息。
  27. 根据权利要求21-26任一项所述的第一核心网设备，其特征在于，所述处理单元通过所述通信单元向所述第二核心网设备发送第一切换请求的响应消息之后，还用于从所述第一网关接收承载创建请求消息；以及用于通过所述通信单元从所述接入网设备接收切换到第一制式网络的完成消息；以及用于通过所述通信单元向所述接入网设备发送承载建立请求消息；以及用于通过所述通信单元从所述接入网设备接收承载建立响应消息；以及用于通过所述通信单元向所述第一网关发送承载创建响应消息。
  28. 根据权利要求27所述的第一核心网设备，其特征在于，所述处理单元通过所述通信单元从所述接入网设备接收切换到第一制式网络的完成消息之后，还用于通过所述通信单元向所述第二核心网设备发送切换完成通知消息；以及用于通过所述通信单元从所述第二核心网设备接收切换完成确认消息。
  29. 一种第二核心网设备，其特征在于，包括：处理单元和通信单元，
    所述处理单元用于通过所述通信单元从接入网设备接收切换要求消息，其中，所述第二核心网设备和所述接入网设备应用于第二制式网络；以及用于 通过所述通信单元向第一核心网设备发送第一切换请求，所述第一切换请求携带第一互联网协议IP地址，所述第一IP地址用于终端在第一制式网络的第一接入点名称APN的建立过程，其中，所述第一核心网设备应用于所述第一制式网络，所述第一IP地址为所述第二制式网络为所述终端分配的IP地址；以及用于通过所述通信单元从所述第一核心网设备接收所述第一切换请求的响应消息，所述第一切换请求的响应消息携带第三IP地址，所述第三IP地址为所述第一制式网络在所述第一APN的建立过程中为所述终端分配的IP地址；以及用于通过所述通信单元向所述接入网设备发送切换要求响应消息。
  30. 根据权利要求29所述的第二核心网设备，其特征在于，所述第一切换请求还携带指示信息，所述指示信息用于指示所述第一核心网设备在完成所述第一APN的建立过程之后向所述第二核心网设备发送第一通知消息，所述处理单元还用于从所述第一核心网设备接收所述第一通知消息，所述第一通知消息用于通知所述第二核心网设备：所述第一核心网设备基于所述第一IP地址为所述终端建立了所述第一APN，所述第一通知消息中携带所述第一IP地址和所述第三IP地址。
  31. 根据权利要求30所述的第二核心网设备，其特征在于，所述处理单元在通过所述通信单元从所述第一核心网设备接收所述第一通知消息之后，还用于向第二策略设备发送第三通知消息，所述第三通知消息用于通知所述第二策略设备：所述第一核心网设备基于所述第一IP地址为所述终端建立了所述第一APN，其中，所述第二策略设备应用于所述第二制式网络，所述第三通知消息中携带所述第三IP地址。
  32. 根据权利要求29至31中任一项所述的第二核心网设备，其特征在于，所述第一切换请求还携带第二IP地址，所述第二IP地址用于所述终端在所述第一制式网络的第二APN的建立过程，其中，所述第二IP地址为所述第二制式网络为所述终端分配的IP地址。
  33. 根据权利要求32所述的第二核心网设备，其特征在于，所述第一切换请求的响应消息携带以下至少一项：
    附着接受消息，所述附着接受消息携带所述第一APN的信息、所述第一 IP地址、所述第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址；
    分组数据网络PDN连接建立接受消息，所述PDN连接建立接受消息携带所述第二APN的信息；或者，
    会话管理SM请求消息，所述SM请求消息携带所述终端在所述第一制式网络的承载信息。
  34. 根据权利要求33所述的第二核心网设备，其特征在于，所述切换要求响应消息携带以下至少一项：所述附着接受消息、所述PDN连接建立接受消息或所述SM请求消息。
  35. 根据权利要求29-24任一项所述的第二核心网设备，其特征在于，所述处理单元通过所述通信单元从所述第一核心网设备接收第一切换请求的响应消息之后，还用于通过所述通信单元向所述第二策略设备发送第七通知消息，所述第七通知消息用于通知所述第二策略设备：所述终端从所述第二制式网络切换到所述第一制式网络。
  36. 根据权利要求35所述的第二核心网设备，其特征在于，所述第七通知消息携带所述第一IP地址、所述第三IP地址和第三使用信息，所述第三使用信息用于指示应用功能设备在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，其中所述应用功能设备应用于所述第一制式网络和所述第二制式网络。
  37. 根据权利要求29-24任一项所述的第二核心网设备，其特征在于，所述处理单元通过所述通信单元从所述第一核心网设备接收第一切换请求的响应消息之后，还用于通过所述通信单元向所述第一核心网设备发送切换完成确认消息；以及用于通过所述通信单元向所述第二策略设备发送第九通知消息，所述第九通知消息用于通知所述第二策略设备：所述终端从所述第二制式网络切换到所述第一制式网络。
  38. 根据权利要求37所述的第二核心网设备，其特征在于，所述第九通知消息携带所述第一IP地址、所述第三IP地址和第三使用信息，所述第三使用信息用于指示应用功能设备在所述第一制式网络中使用所述第三IP地址替 代所述第一IP地址，其中所述应用功能设备应用于所述第一制式网络和所述第二制式网络。
  39. 一种第二接入网设备，其特征在于，包括：处理单元、第一通信单元和第二通信单元，
    所述处理单元，用于通过所述第一通信单元向第二核心网设备发送切换要求消息，所述切换要求消息用于请求将终端从第二制式网络切换到第一制式网络，其中，所述第二接入网设备和所述第二核心网设备应用于所述第二制式网络；以及用于通过所述第一通信单元从所述第二核心网设备接收切换要求响应消息，所述切换要求响应消息携带以下至少一项：附着接受消息、分组数据网络PDN连接建立接受消息或会话管理SM请求消息，其中，所述附着接受消息携带第一核心网设备为所述终端在所述第一制式网络建立的第一接入点名称APN的信息、所述第二制式网络为所述终端分配的第一互联网协议IP地址、所述第一制式网络在所述第一APN的建立过程中为所述终端分配的第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用所述第三IP地址替代所述第一IP地址，所述PDN连接建立接受消息携带所述第一核心网设备为所述终端在所述第一制式网络建立的第二APN的信息，所述SM请求消息携带所述终端在所述第一制式网络的承载信息；以及用于通过所述第二通信单元向所述终端发送切换命令消息，所述切换命令消息携带以下至少一项：所述附着接受消息、所述PDN连接建立接受消息或所述SM请求消息。
  40. 一种终端，其特征在于，包括：处理单元和通信单元，
    所述处理单元用于通过所述通信单元从第二接入网设备接收切换命令消息，所述切换命令消息携带以下至少一项：附着接受消息、分组数据网络PDN连接建立接受消息或会话管理SM请求消息，其中，所述附着接受消息携带第一核心网设备为所述终端在所述第一制式网络建立的第一接入点名称APN的信息、所述第二制式网络为所述终端分配的第一互联网协议IP地址、所述第一制式网络在所述第一APN的建立过程中为所述终端分配的第三IP地址和第一使用信息，所述第一使用信息用于指示所述终端在所述第一制式网络中使用 所述第三IP地址替代所述第一IP地址，所述PDN连接建立接受消息携带所述第一核心网设备为所述终端在所述第一制式网络建立的第二APN的信息，所述SM请求消息携带所述终端在所述第一制式网络的承载信息；其中，所述第二接入网设备应用于所述第二制式网络；以及用于根据所述附着接受消息、所述PDN连接建立接受消息或所述SM请求消息中的至少一项接入所述第一制式网络；以及用于通过所述通信单元向第一接入网设备发送切换完成消息，所述第一接入网设备应用于所述第一制式网络。
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