WO2019137549A1 - 通信方法和通信装置 - Google Patents

通信方法和通信装置 Download PDF

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Publication number
WO2019137549A1
WO2019137549A1 PCT/CN2019/071718 CN2019071718W WO2019137549A1 WO 2019137549 A1 WO2019137549 A1 WO 2019137549A1 CN 2019071718 W CN2019071718 W CN 2019071718W WO 2019137549 A1 WO2019137549 A1 WO 2019137549A1
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WO
WIPO (PCT)
Prior art keywords
pdu session
indication information
handover indication
network element
session
Prior art date
Application number
PCT/CN2019/071718
Other languages
English (en)
French (fr)
Inventor
朱奋勤
景昊
Original Assignee
华为技术有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Priority to EP19738645.1A priority Critical patent/EP3737157B1/en
Priority to BR112020014358-8A priority patent/BR112020014358A2/pt
Publication of WO2019137549A1 publication Critical patent/WO2019137549A1/zh
Priority to US16/929,247 priority patent/US11395192B2/en
Priority to US17/851,192 priority patent/US11792695B2/en

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    • 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
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0011—Control or signalling for completing the hand-off for data sessions of end-to-end connection
    • H04W36/0022—Control or signalling for completing the hand-off for data sessions of end-to-end connection for transferring data sessions between adjacent core network technologies
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L67/00—Network arrangements or protocols for supporting network services or applications
    • H04L67/14—Session management
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L67/00—Network arrangements or protocols for supporting network services or applications
    • H04L67/14—Session management
    • H04L67/148—Migration or transfer of sessions
    • 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
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0011—Control or signalling for completing the hand-off for data sessions of end-to-end connection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0011—Control or signalling for completing the hand-off for data sessions of end-to-end connection
    • H04W36/0016—Hand-off preparation specially adapted for end-to-end data sessions
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0011—Control or signalling for completing the hand-off for data sessions of end-to-end connection
    • H04W36/0022—Control or signalling for completing the hand-off for data sessions of end-to-end connection for transferring data sessions between adjacent core network technologies
    • H04W36/00222—Control or signalling for completing the hand-off for data sessions of end-to-end connection for transferring data sessions between adjacent core network technologies between different packet switched [PS] network technologies, e.g. transferring data sessions between LTE and WLAN or LTE and 5G
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/0005—Control or signalling for completing the hand-off
    • H04W36/0011—Control or signalling for completing the hand-off for data sessions of end-to-end connection
    • H04W36/0027—Control or signalling for completing the hand-off for data sessions of end-to-end connection for a plurality of data sessions of end-to-end connections, e.g. multi-call or multi-bearer end-to-end data connections
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W8/00—Network data management
    • H04W8/02—Processing of mobility data, e.g. registration information at HLR [Home Location Register] or VLR [Visitor Location Register]; Transfer of mobility data, e.g. between HLR, VLR or external networks
    • H04W8/08—Mobility data transfer

Definitions

  • the present application relates to the field of communications and, more particularly, to communication methods and communication devices in the field of communications.
  • the fifth generation (Fifth Generation, 5G) mobile communication technology came into being.
  • the coverage of the 5G network is insufficient. Therefore, when the location of the user equipment (User Equipment, UE) changes, the UE needs a handover session between the 5G network and the fourth generation (Forth Generation, 4G) network.
  • UE User Equipment
  • PDN packet data network
  • APN access point name
  • DNN protocol data unit
  • the UE may have one or more PDU sessions established in 5G, and these PDU sessions may use the same DNN. And 5G does not specify that the same DNN session must select the same session management device, therefore, these one or more PDU sessions with the same DNN may be anchored on different session management devices.
  • 5G does not specify that the same DNN session must select the same session management device, therefore, these one or more PDU sessions with the same DNN may be anchored on different session management devices.
  • 4G in order to control the APN aggregation maximum bit rate (AMBR), one or more PDN connections of the same APN are required to be anchored only on one session management device. When one or more PDU sessions of the same DNN are switched, an uncontrollable situation is caused, resulting in poor system performance.
  • APN aggregation maximum bit rate APN aggregation maximum bit rate
  • the application provides a communication method and communication device to help improve system performance.
  • a communication method including: determining, by a network device, a target PDU session in the established PDU session according to handover indication information of a protocol data unit PDU session established by the terminal in the first network, where the establishing Each PDU session in the PDU session has the same data network name DNN; the network device transmits session information of the target PDU session to the mobility management entity device of the second network.
  • the network device may determine the target PDU session in the established PDU session according to the handover indication information of the established PDU session, so that the target PDU session may be the PDU that can be switched to the second network.
  • the session can avoid the uncontrollable situation caused by the terminal to switch to the same control plane function network element of the second network when the PDU session established by the first network is switched, which helps control the switching of the PDU session, thereby improving system performance.
  • the PDU session established by the terminal in the first network may be one or more.
  • the handover indication information of the PDU session established by the terminal in the first network is one; if the PDU session established by the terminal in the first network is multiple, the terminal The handover indication information of the PDU session established in the first network may be handover indication information of multiple PDU sessions.
  • the first network is a 5G network
  • the second network is a 4G network.
  • the network device is a user data management network element or an access and mobility management function entity.
  • the handover indication information is used to indicate a handover priority of each PDU session in the established PDU session, where determining a target PDU session in the established PDU session includes: The network device determines the PDU session with the highest handover priority among the established PDU sessions as the target PDU session.
  • the switching priority of a PDU session can be represented numerically.
  • the PDU session with the highest priority switching may be one or more.
  • the handover indication information is used to indicate whether each PDU session in the established PDU session is capable of handover; wherein determining a target PDU session in the established PDU session includes: If the handover indication information indicates that there is only one PDU session that can be switched, the network device determines that the switchable PDU session is the target PDU session; and the handover indication information indicates that at least two PDU sessions can be switched. In case, the network device determines the target PDU session in the at least two PDU sessions.
  • the network device determines the target PDU session in the at least two PDU sessions, including: If the at least two PDU sessions belong to the same control plane function network element, the network device determines the at least two sessions as the target session; if the at least two PDU sessions belong to different control plane function networks And determining, by the network device, the target PDU session in the at least two PDU sessions according to the auxiliary information of each of the at least two PDU sessions of the at least two PDU sessions.
  • the handover indication information may indicate that the PDU session can be switched, and the network device may obtain at least two PDU sessions indicated by the handover indication information, and the network device determines whether the at least two PDU sessions belong to the same control. If the function network element belongs to the same control plane function network element, the at least two PDU sessions can be switched, that is, the target PDU session; if the at least two PDU sessions do not belong to the same control plane function network
  • the network device may determine the target PDU session according to the auxiliary information of the at least two PDU sessions, or the network device may determine the priority of the at least two PDU sessions according to the auxiliary information of the at least two PDU sessions, and switch the priority The highest PDU session is determined to be the target PDU session.
  • the method before the determining, by the network device, the target PDU session in the established PDU session, according to the handover indication information of the protocol data unit PDU session established by the terminal in the first network, the method further includes: Receiving, by the network device, auxiliary information of the first PDU session in the established PDU session sent by the first control plane function network element; the network device determining, according to the auxiliary information, a handover indication of the first PDU session Information
  • the network device may be a user data management network element or an access and mobility management device.
  • the method further includes: the user data management network element sending a handover indication of the first PDU session to the first control plane function network element information.
  • the user data management network element may determine, according to the auxiliary information of the first PDU session sent by the first control plane function network element, the handover indication information of the first PDU session according to the auxiliary information of the first PDU session, and And transmitting the determined handover indication information of the first PDU session to the first control plane function network element.
  • the auxiliary information includes at least one of the following: an internet protocol (IP) address version corresponding to the PDU session, a single network slice assistance information corresponding to the PDU session, a session corresponding to the PDU session, and a service continuity.
  • IP internet protocol
  • the method before the determining, by the network device, the target PDU session in the established PDU session, according to the handover indication information of the protocol data unit PDU session established by the terminal in the first network, the method includes: The network device receives handover indication information of a PDU session established by the terminal from the at least one control plane function network element in the first network.
  • the network device is a user data management network element, and the network device is in the established PDU session according to the handover indication information of the protocol data unit PDU session established by the terminal in the first network.
  • the method includes: the user data management network element receiving initial handover indication information of the second PDU session in the PDU session established by the terminal in the first network from the second control plane function network element; The user data management network element adjusts the initial handover indication information to obtain handover indication information of the second PDU session; the method further includes: sending, by the user data management network element, the second control plane function network element The switching indication information of the second PDU session.
  • the user data management network element may adjust the initial handover indication information of the second PDU session sent by the second control plane function network element, and may send the adjusted handover indication information of the second PDU session to the second control. Face function network element.
  • the specific adjustment manner is based on the local policy, which is not limited in this embodiment.
  • the session information of the target PDU session includes an identifier of a control plane function network element corresponding to the target PDU session and a DNN of the target PDU session.
  • a communication method including: a terminal acquiring handover indication information of a protocol data unit PDU session established in a first network, where each PDU session in the established PDU session has the same data network name DNN The terminal determines a target PDU session in the established PDU session according to the handover indication information of the established PDU session; the terminal sends the first control plane function network element to the first control plane through the mobility management entity device of the second network Sending an identifier of the target PDU session.
  • the terminal may determine the target PDU session in the established PDU session according to the handover indication information of the established PDU session, so that the target PDU session may be a PDU session that can be switched to the second network.
  • the uncontrollable situation caused by the terminal to switch to the same control plane function network element of the second network in the PDU session established by the first network can be avoided, which helps control the switching of the PDU session, thereby improving system performance.
  • the handover indication information is used to indicate a handover priority of each PDU session in the established PDU session, where determining a target PDU session in the established PDU session includes: The terminal determines, as the target PDU session, a PDU session with the highest handover priority among the established PDU sessions.
  • the handover indication information is used to indicate whether each PDU session in the established PDU session is capable of switching; wherein, determining a target PDU session in the established PDU session, including: the terminal Determining a PDU session that can be switched in the established PDU session is the target PDU session.
  • the terminal sends the identifier of the target PDU session to the first control plane function network element via the mobility management entity device of the second network, including: the terminal to the mobility management entity device Sending an identifier of the target PDU session and a DNN of the target PDU session, the DNN of the target PDU session is used by the mobility management entity device to determine the first control plane function network element to facilitate the mobility
  • the management entity device sends the identifier of the target PDU session to the first control plane function network element.
  • the sending, by the terminal, the identifier of the target PDU session and the data network name of the target PDU session to the mobility management entity device including: the terminal to the mobility management entity device Sending a first request message, where the first request message carries an identifier of the target PDU session and a DNN of the target PDU session, where the first request message is an attach request message or a session establishment request message.
  • the acquiring, by the terminal, the handover indication information of the PDU session established in the first network includes: receiving, by the terminal, a handover indication of the established PDU session sent by the at least one control plane function network element information.
  • the terminal may receive the handover indication information of the established PDU session sent by the at least one control plane function network element, and the handover indication information of the established PDU session sent by the at least one control plane function network element. It may be determined by the at least one control plane function network element itself, or the at least one control plane function network element is sent by the user data management device, which is not limited in this embodiment of the present application.
  • the terminal acquiring the handover indication information of the PDU session established in the first network, where the terminal sends the initial handover indication information of the first PDU session to the second control plane function network element.
  • the initial handover indication information is used to determine handover indication information of the first PDU session; the terminal receives handover indication information of the first PDU session sent by the second control plane function network element.
  • the terminal may send the initial handover indication information of the first PDU session to the second control plane function network element, and the second control plane function network element may adjust the initial handover indication information of the first PDU session to obtain the first PDU session.
  • the switching instruction information, or the second control plane function network element may send the initial handover indication information of the first PDU session to the user data management network element, and the user data management network element adjusts the initial handover indication information of the first PDU session,
  • the switching instruction information of the first PDU session is sent to the second control plane function network element, and the second control plane function network element sends the handover indication information of the first PDU session to the terminal.
  • a third aspect provides a communication method, including: a first control plane function network element receiving a session establishment request message sent by a terminal, where the session establishment request message is used to request to establish a first protocol data unit PDU session; A control plane function network element acquires handover indication information of the first PDU session.
  • the first control plane function network element may be any one of a plurality of control plane function network elements.
  • the session establishment request message received by the multiple control plane function network elements may respectively request to establish multiple PDU sessions, and the multiple PDU sessions have the same DNN.
  • the handover indication information is used to indicate a priority of the first PDU session or to indicate whether the first PDU session can be switched.
  • the session establishment request message includes the handover indication information of the first PDU session, where the first control plane function network element acquires the handover indication information of the first PDU session, including: The first control plane function network element acquires the handover indication information of the first PDU session in the session establishment request message; the method further includes: the first control plane function network element to the user data management network element Or the access and mobility management function device sends the handover indication information of the first PDU session.
  • the session establishment request message sent by the terminal to the first control plane function network element carries the handover indication information of the first PDU session, and the first control plane function network element may obtain the first in the session establishment request message.
  • the switching indication information of a PDU session may be obtained.
  • the first control plane function network element acquires the handover indication information of the handover of the first PDU session, where the first control plane function network element acquires an initial of the first PDU session. And switching the indication information; the first control plane function network element acquires the handover indication information of the first PDU session that is adjusted according to the initial handover indication information; the method further includes: the first control plane function network element And transmitting, by the terminal or the user data management network element or the access and mobility management function device, the handover indication information of the first PDU session.
  • the initial handover indication information of the first PDU session may be adjusted to be the handover indication information of the first PDU session.
  • the first control plane function network element receives the initial handover indication information of the first PDU session, and the session establishment request message may carry the initial handover indication information, and the first control plane function network may be included.
  • the element may adjust the initial handover indication information of the first PDU session, and the first control plane function network element may send the adjusted handover indication information of the first PDU session to the terminal, for example, through the PCO sending terminal, so that the terminal can receive
  • the switching indication information of the multiple PDU sessions sent by the multiple control plane function network elements the terminal may determine the target PDU session according to the handover indication information of the multiple PDU sessions, that is, the PDU session that needs to be switched.
  • the first control plane function network element may send the adjusted handover indication information of the first PDU session to the user data management network element, so that the user data management network element may receive multiple PDU sessions sent by multiple control plane function network elements.
  • the switching information indicates that the user data management network element can determine the target PDU session according to the handover indication information of the multiple PDU sessions, that is, the PDU session that needs to be switched.
  • the first control plane function network element may send the adjusted handover indication information of the first PDU session to the access and mobility management function device, so that the access and mobility management function device may receive multiple control plane function network element transmissions.
  • the handover indication information of the multiple PDU sessions, the access and mobility management function device may determine the target PDU session according to the handover indication information of the multiple PDU sessions, that is, the PDU session that needs to be switched.
  • the first control plane function network element may receive the initial handover indication information of the first PDU session or the initial handover indication information of the first PDU session, and then send the initial handover indication information of the first PDU session to the user.
  • the data management function network element, the user management function network element may modulate the initial handover indication information of the first PDU session to obtain the handover indication information of the first PDU session, and the user management function network element adjusts the handover indication of the first PDU session.
  • the information is sent to the first control plane function network element, and the first control plane function network element can send the adjusted handover indication information of the first PDU session to the access and mobility management function device, so that the access and mobility management functions are performed.
  • the device may receive the handover indication information of the multiple PDU sessions sent by the multiple control plane function network elements, and the access and mobility management function device may determine the target PDU session according to the handover indication information of the multiple PDU sessions, that is, the PDU that needs to be switched. Conversation.
  • the first control plane function network element may send the handover indication information of the adjusted first PDU session to the terminal, so that the terminal may receive the handover indication information of the multiple PDU sessions sent by the multiple control plane function network elements, and the terminal may The handover indication information of the PDU sessions determines the target PDU session, that is, the PDU session that needs to be handed over.
  • the first control plane function network element acquires the handover indication information of the handover of the first PDU session, including: the first control plane function network element sends the to the user data management network element Auxiliary information of the first PDU session; the first control plane function network element receives the handover indication information of the first PDU session sent by the user data management network element, and the handover indication information of the first PDU session is The auxiliary information of the first PDU session determines that the auxiliary information of the first PDU session includes an Internet Protocol IP address version corresponding to the first PDU session, a single network slice assistance information corresponding to the first PDU session, and the a session and service continuity SSC mode corresponding to the first PDU session, an allocation and retention handover priority ARP corresponding to the first PDU session, a corresponding service type of the first PDU session, and a corresponding PDU session At least one of establishing time; the method further comprising: the first control plane function network element transmitting the first PDU session to the terminal or the access and mobility management function
  • the method further includes: a first control plane function network element receiving an identifier of the target PDU session and a DNN of the target PDU session sent by a mobility management device of a second network, where a control plane function network element searches for a target PDU session according to the identifier of the target PDU session and the DNN of the target PDU session in a plurality of PDU sessions corresponding to the DNN saved by itself, and if the target PDU session is found, Then, the target PDU session is switched, and if the target PDU session is not found, the target PDU session is rejected.
  • the method further includes: the first control plane function network element receives the first data network name sent by the mobility management entity device of the second network, where the first data network name is the terminal to the second network.
  • the data network name of the current PDU session sent by the mobility management entity device corresponds to the PDU session update request
  • the first control plane function network element receives the session update request corresponding to the first data network name
  • the first control plane function network The PDU session corresponding to the first data network name is obtained according to the first data network name. If the corresponding PDU session is one, the PDU session is a session that needs to be switched. If the corresponding PDU session is multiple, the first control plane function network element selects one PDU session as the PDU session to be switched.
  • the first control plane function network element may select one PDU session as the PDU session to be handed over, or the auxiliary information of the PDU session determines the switched PDU session.
  • the first control plane function network element sends the identifier of the switched PDU session to the terminal.
  • the method further includes: the first control plane function network element sends a data network name DNN of the first PDU session and the first control plane function network element to a user data management network element.
  • the first control plane function network element may send session information of the first PDU session to the user data management network element, where the session information includes handover indication information of the first PDU session, a DNN of the first PDU session, and a first control plane.
  • the control network element may be configured to simultaneously send the handover indication information of the first PDU session, the DNN of the first PDU session, and the identifier of the first control plane control network element to the user data management network element. In this way, the user data management network element can save the session information of the first PDU session.
  • the user data management network element When the user data management network element receives the session information of multiple PDU sessions (having the same DNN), according to the handover indication information of the multiple PDU sessions. Determining the target PDU session, and then transmitting the DNN of the target PDU session and the identifier of the control plane function network element corresponding to the target PDU session to the mobility management function entity device of the second network.
  • the fourth aspect provides a communication method, including: the terminal sends a first data network name corresponding to the current PDU session to the mobility management entity device of the second network; and the terminal receives the switched PDU session sent by the control plane function network element.
  • the identifier identifies the PDU session that has been switched according to the identity of the PDU session.
  • the terminal receives the PCO sent by the control plane function network element, obtains the identifier of the PDU session that has been switched in the PCO, and determines the PDU session that has been switched according to the identifier of the PDU session, so that the UE can connect the PDN and the corresponding The conversations are related.
  • the terminal sends the first data network name corresponding to the current PDU session to the mobility management entity device of the second network, where the terminal sends the attach request to the mobility management entity device of the second network.
  • the message or session establishment request message, the attachment request message or the session establishment request message carries the data network name corresponding to the current PDU session.
  • the control plane function network element determines the PDU that needs to be switched. After the session, the PDU session is switched in the attaching process. If the terminal carries the data network name corresponding to the current PDU session in the session establishment request message, the control plane function network element determines the flow of the session establishment request after determining the PDU session to be switched. Switch the PDU session. After the handover is completed, the control plane function network element sends the identifier of the PDU session that has been switched to the terminal. For example, the control plane function network element sends a PCO to the terminal, and the PCO carries the identifier of the PDU session that has been switched.
  • a communication apparatus for performing the method of any of the first aspect or the first aspect of the first aspect.
  • the apparatus comprises means for performing the method of any of the first aspect or the first aspect of the first aspect described above.
  • a communication apparatus for performing the method of any of the possible implementations of the second aspect or the second aspect above.
  • the apparatus comprises means for performing the method of any of the possible implementations of the second aspect or the second aspect described above.
  • a communication apparatus for performing the method of any of the above-described third or third possible implementations.
  • the apparatus comprises means for performing the method of any of the possible implementations of the third aspect or the third aspect described above.
  • a communication apparatus for performing the method of any of the above-described fourth or fourth possible implementations.
  • the apparatus comprises means for performing the method of any of the above-described fourth or fourth aspects of the fourth aspect.
  • a communication device comprising: a transceiver (which may include a transmitter and a receiver), a memory, and a processor.
  • the transceiver, the memory and the processor are in communication with each other via an internal connection path for storing instructions for executing instructions stored in the memory to control the receiver to receive signals and to control the transmitter to transmit signals
  • the apparatus is caused to perform the method of the first aspect or any of the possible implementations of the first aspect.
  • a communication device comprising: a transceiver (which may include a transmitter and a receiver), a memory, and a processor.
  • the transceiver, the memory and the processor are in communication with each other via an internal connection path for storing instructions for executing instructions stored in the memory to control the receiver to receive signals and to control the transmitter to transmit signals
  • the apparatus is caused to perform the method of any of the possible implementations of the second aspect or the second aspect.
  • a communication device comprising: a transceiver (which may include a transmitter and a receiver), a memory, and a processor.
  • the transceiver, the memory and the processor are in communication with each other via an internal connection path for storing instructions for executing instructions stored in the memory to control the receiver to receive signals and to control the transmitter to transmit signals
  • the apparatus is caused to perform the method of any of the possible implementations of the third aspect or the third aspect.
  • an apparatus for communication comprising: a transceiver (which may include a transmitter and a receiver), a memory, and a processor.
  • the transceiver, the memory and the processor are in communication with each other via an internal connection path for storing instructions for executing instructions stored in the memory to control the receiver to receive signals and to control the transmitter to transmit signals
  • the apparatus is caused to perform the method of any of the possible implementations of the fourth aspect or the fourth aspect.
  • a thirteenth aspect a system for processing a service, comprising the device of the fifth aspect or any alternative implementation thereof, the device of the sixth aspect or any alternative implementation thereof, and the seventh aspect Or a device in any of the alternative implementations.
  • the system comprises the device in the fifth aspect or any alternative implementation thereof, the device in the sixth aspect or any alternative implementation thereof, and the eighth aspect or any one of the optional The device in the implementation.
  • the system includes the device in the ninth aspect or any alternative implementation thereof, the device in the tenth aspect or any alternative implementation thereof, and the eleventh aspect or any one of the Select the device in the implementation.
  • the system includes the device in the ninth aspect or any alternative implementation thereof, the device in the tenth aspect or any alternative implementation thereof, and the twelfth aspect or any one thereof Select the device in the implementation.
  • a computer readable storage medium is provided, the instructions being stored in a computer readable storage medium, when executed on a computer, causing the computer to perform any of the first aspect or the first aspect The method in the implementation.
  • a computer readable storage medium is provided, the instructions being stored in the computer readable storage medium, when executed on a computer, causing the computer to perform any of the possible aspects of the second aspect or the second aspect The method in the implementation.
  • a computer readable storage medium is provided, the instructions being stored in the computer readable storage medium, when executed on a computer, causing the computer to perform any of the third aspect or the third aspect The method in the implementation.
  • a computer readable storage medium stores instructions that, when run on a computer, cause the computer to perform any of the fourth or fourth aspects The method in the implementation.
  • the present application provides a computer program product comprising instructions which, when run on a computer, cause the computer to perform the method of any of the first aspect or the first aspect of the first aspect.
  • the present application provides a computer program product comprising instructions which, when run on a computer, cause the computer to perform the method of any of the above-described second or second aspect.
  • the present application provides a computer program product comprising instructions which, when run on a computer, cause the computer to perform the method of any of the above-described third or third aspects.
  • the present application provides a computer program product comprising instructions which, when run on a computer, cause the computer to perform the method of any of the above-described fourth or fourth aspects.
  • the present application provides a communication chip in which an instruction is stored, when it is run on a terminal or a network device or a control plane function network element, so that the terminal or the network device or the control plane function network element performs the above Any of the methods described in the various aspects.
  • FIG. 1 is a schematic diagram of a 4G network and a 5G network interworking architecture system provided by an embodiment of the present application.
  • FIG. 2 is a schematic diagram of a communication method provided by an embodiment of the present application.
  • FIG. 3 is a schematic diagram of another communication method provided by an embodiment of the present application.
  • FIG. 4 is a schematic diagram of another communication method provided by an embodiment of the present application.
  • FIG. 5 is a schematic diagram of still another communication method provided by an embodiment of the present application.
  • FIG. 6 is a schematic diagram of still another communication method provided by an embodiment of the present application.
  • FIG. 7 is a schematic diagram of still another communication method provided by an embodiment of the present application.
  • FIG. 8 is a schematic diagram of still another communication method provided by an embodiment of the present application.
  • FIG. 9 is a schematic diagram of still another communication method provided by an embodiment of the present application.
  • FIG. 10 is a schematic diagram of still another communication method provided by an embodiment of the present application.
  • FIG. 11 is a schematic diagram of still another communication method provided by an embodiment of the present application.
  • FIG. 12 is a schematic diagram of still another communication method provided by an embodiment of the present application.
  • FIG. 13 is a schematic diagram of still another communication method provided by an embodiment of the present application.
  • FIG. 14 is a schematic block diagram of a communication apparatus according to an embodiment of the present application.
  • FIG. 15 is a schematic block diagram of another communication apparatus according to an embodiment of the present application.
  • FIG. 16 is a schematic block diagram of still another communication apparatus provided by an embodiment of the present application.
  • FIG. 17 is a schematic block diagram of still another communication apparatus provided by an embodiment of the present application.
  • FIG. 18 is a schematic block diagram of still another communication apparatus according to an embodiment of the present application.
  • FIG. 19 is a schematic block diagram of still another communication apparatus provided by an embodiment of the present application.
  • the embodiment of the present invention provides a method for mobility management, which can be applied to the 4G network and the 5G network interworking architecture system 100 shown in FIG. 1.
  • the user plane function is shared between the 4G network and the 5G network.
  • UPF user plane function
  • PGW-U PDN gateway user plane function
  • SMF session management function
  • PDN gateway control plane function PDN gateway control plane function
  • PGW-C PDN gateway control plane function
  • PCF policy control function
  • PCF policy and charging rules function
  • PCF policy and charging rules function
  • HSS home subscriber server
  • UDM unified data Unified data management
  • UPF is the user plane function of the 5G network
  • PGW-U is the gateway user plane function of the 4G network corresponding to the UPF
  • SMF is the session management function of the 5G network
  • PGW-C is the corresponding to the SMF.
  • the PCF is the policy control function of the 5G network
  • the PCRF is the policy charging rule function of the 4G network corresponding to the PCF.
  • coupling means that the same device has the functions of two entities at the same time.
  • the HSS+UDM entity is referred to as a user data management network element
  • the PGW-C entity + SMF entity is referred to as a control plane function network element
  • the UPF entity + PGW-U entity is called
  • the user plane function network element is uniformly described here, and will not be described below.
  • the network device after the above-mentioned connection may also use other names, which is not specifically limited in this embodiment of the present application.
  • the foregoing 4G network and 5G network interworking architecture may further include a Mobility Management Entity (MME) and a Serving Gateway (SGW), and access and movement in the 5G network.
  • MME Mobility Management Entity
  • SGW Serving Gateway
  • AMF Access and Mobility Management Function
  • the terminal accesses the 4G network through an evolved universal terrestrial radio access network (E-UTRAN) device, and the terminal passes the next generation radio access network (NG-RAN) device. Access to 5G networks.
  • E-UTRAN evolved universal terrestrial radio access network
  • NG-RAN next generation radio access network
  • the E-UTRAN device communicates with the MME through the S1-MME interface, the E-UTRAN device communicates with the SGW through the S1-U interface, the MME communicates with the SGW through the S11 interface, and the MME communicates with the user data management entity through the S6a interface, and the MME passes the N26 interface.
  • the SGW communicates with the PGW-U entity + UPF entity through the S5-U interface
  • the SGW communicates with the PGW-C entity + SMF entity through the S5-C interface
  • the PGW-U entity + UPF entity passes the N3 interface and the NG-RAN Device communication
  • the PGW-U entity + UPF entity communicates with the PGW-C entity + SMF entity through the N4 interface
  • the PGW-C entity + SMF entity communicates with the PCRF entity + PCF entity through the N7 interface
  • the HSS+UDM entity passes the N10 interface and the PGW -C entity + SMF entity communication
  • HSS+UDM entity communicates with AMF entity through N8 interface
  • PCRF entity + PCF entity communicates with AMF entity through N15 interface
  • PGW-C entity + SMF entity communicates with AMF entity through N11 interface
  • AMF entity The NMF entity communicates with the NG-RAN device through the N2 interface
  • the AMF entity communicates with the terminal through the N1
  • the N26 interface between the MME and the AMF may not exist in some scenarios in the foregoing interworking architecture.
  • the N26 interface may be used for terminal context transfer and handover procedures. This application will describe whether there is an N26 interface between the MME and the AMF, respectively describing the possible implementations.
  • the terminal is a UE
  • the name of the interface between the network elements in FIG. 1 is only an example.
  • the interface name may be another name. limited.
  • the NG-RAN device in the 5G network may also be referred to as an access device, and the access device refers to a device that accesses the core network, for example, a base station, a broadband network service gateway (broadband network gateway, BNG), aggregation switch, non-3GPP access equipment, etc.
  • the base station may include various types of base stations, such as a macro base station, a micro base station (also referred to as a small station), a relay station, an access point, and the like, which are not specifically limited in this embodiment of the present application.
  • the 4G network may also include a general packet radio system (GPRS) service support node (SGSN), etc., 5G.
  • the network may also include an authentication service function (AUSF) entity and a network slice selection function (NSSF) entity, which are not specifically limited in this embodiment of the present application.
  • GPRS general packet radio system
  • SGSN general packet radio system
  • AUSF authentication service function
  • NSSF network slice selection function
  • the terminals involved in the embodiments of the present application may include various handheld devices having wireless communication functions, in-vehicle devices, wearable devices, computing devices, or other processing devices connected to the wireless modem; and may also include a subscriber unit ( Subscriber unit), cellular phone, smart phone, wireless data card, personal digital assistant (PDA) computer, tablet computer, wireless modem (modem), handheld device, a laptop computer, a cordless phone, or a wireless local loop (WLL) station, a machine type communication (MTC) terminal, a user equipment (UE), Mobile station (MS), terminal device, etc.
  • Subscriber unit Subscriber unit
  • cellular phone smart phone
  • wireless data card personal digital assistant
  • modem modem
  • WLL wireless local loop
  • MTC machine type communication
  • UE user equipment
  • MS Mobile station
  • the terminal may provide an APN to the MME when initiating a packet service.
  • the MME performs domain name resolution based on the APN provided by the terminal, and obtains the address of the session management network element (for example, the Internet Protocol address), thereby accessing the terminal to the PDN corresponding to the APN.
  • the session management network element for example, the Internet Protocol address
  • the terminal may provide the S-NSSAI and the DNN to the AMF when initiating the establishment of the PDU session.
  • the AMF determines the address of the session management network element based on the S-NSSAI, DNN, and other information (such as the subscription information of the terminal and the local carrier policy, etc.).
  • the determined session management network element establishes a PDU session for the terminal based on the S-NSSAI and the DNN.
  • the APN in the 4G network is equivalent to the DNN in the 5G network.
  • the PDN connection in the 4G network is equivalent to the PDU session in the 5G network.
  • the UE may establish one or more PDU sessions in the 5G, and these PDU sessions may use the same DNN, these one or more PDU sessions with the same DNN may be anchored on different control plane functional network elements.
  • APN aggregation maximum bit rate AMBR
  • one or more PDN connections of the same APN are required to be anchored only on one control plane function network element. If one or more PDU sessions with the same DNN in 5G are switched to one or more PDN connections in the 4G with the same APN, how to perform the handover session is an urgent problem to be solved.
  • the target PDU session may be determined in at least one PDU session having the same DNN according to the handover indication information, and the target PDU session serves as a switchable PDU session, thereby being able to avoid how to have the same DNN. Switching at least one PDU session results in an uncontrollable situation and can improve system performance.
  • FIG. 2 shows a communication method 200 provided by an embodiment of the present application.
  • the method 200 includes:
  • the network device determines, in the established PDU session, a target PDU session according to the handover indication information of the protocol data unit PDU session established by the terminal in the first network, where each PDU session in the established PDU session has the same Data network name DNN.
  • the PDU session established by the terminal in the first network may be one or more.
  • the target PDU session may be one or more.
  • the network device may be a user data management network element or an access and mobility management function device.
  • the terminal establishes N PDU sessions in the first network
  • the M PDU sessions in the N PDU sessions have the same data network name
  • N is greater than or equal to M
  • M and N are positive integers.
  • the handover indication information of the established PDU session may include: corresponding handover indication information may exist in each PDU session in the established PDU session, and the handover indication information may be the same or different in the established PDU sessions. PDU session. Or at least one PDU session in the established PDU session has corresponding handover indication information.
  • the handover indication information may indicate whether the PDU session can be switched. For example, only one PDU session in the three PDU sessions can be switched.
  • the handover indication information of the PDU session indicates that the PDU session can be switched, and whether the remaining two PDU sessions can be switched can be omitted, and cannot be switched by default.
  • the handover indication information is used to indicate a handover priority of each PDU session in the established DU session
  • S220 includes: the network device performs the highest handover priority among the established PDU sessions.
  • the PDU session is determined to be the target PDU session.
  • the switching priority of each PDU session may be a number indicating a priority level. For example, a priority of 1 indicates the highest priority, that is, a priority is switched to the second network; the priority is 100. Indicates the lowest priority. For example, there are currently 5 PDU sessions, which are session 1, session 2, session 3, session 4, and session 5. The priorities are 1, 2, 3, 4, and 5, respectively.
  • the device determines session 1 as the target session.
  • the handover indication information is used to indicate whether each PDU session in the PDU session can be switched.
  • the handover indication information may be an indication domain, for example, the reference time domain of a certain PDU session is 1 The PDU session can be switched.
  • the indication field of a PDU session is 0, indicating that the PDU session cannot be switched.
  • the method includes: if there is only one PDU session that can be switched indicated by the handover indication information, the network is The device determines that the PDU session that can be switched is the target PDU session, that is, only one PDU session can be switched, the PDU session is a target PDU session; and the handover indication information indicates that at least two PDU sessions can be switched.
  • the network device may arbitrarily select one PDU session in the at least two PDU sessions as the target PDU session or select according to the auxiliary information.
  • a PDU session is used as the target PDU session.
  • the network device determines the target PDU session in the at least two PDU sessions.
  • the network device determines the at least two sessions as the target session, that is, the network device may belong to the same control plane function network element, if the at least two PDU sessions belong to the same control plane function network element.
  • At least two PDU sessions are switched to the second network as target PDU sessions; if the at least two PDU sessions belong to different control plane function network elements, the network device is configured according to each of the at least two PDU sessions
  • the auxiliary information of the PDU session determines the target PDU session in the at least two PDU sessions.
  • the network device may determine, according to the auxiliary information of each PDU session, a handover priority of the at least two PDU sessions; and the network device performs, according to a handover priority of the at least two PDU sessions, the at least two PDU sessions. Determine the target PDU session.
  • the auxiliary information includes at least one of the following: an Internet Protocol IP address version corresponding to the PDU session, a single network slice selection assistance information (S-NSSAI) corresponding to the PDU session, and a PDU session corresponding to the PDU session.
  • S-NSSAI single network slice selection assistance information
  • PDU session corresponding to the PDU session a PDU session corresponding to the PDU session.
  • the handover indication information indicates that the PDU session 1 and the PDU session 2 can be switched.
  • the network device can determine the PDU session 1 as the target PDU session, or The network device may determine that the priority of PDU Session 1 is higher than the priority of PDU Session 2, and that Session 1 is determined to be the target PDU session, in the absence of other higher priority PDU sessions. For another example, if the SSC mode of the PDU session 1 is mode 3 and the SSC mode of the PDU session 2 is mode 2, the network device may determine the PDU session 1 as the target PDU session, or the network device determines that the priority of the PDU session 1 is higher than the PDU.
  • the priority of session 2 in the absence of other higher priority PDU sessions, the network device can determine PDU session 1 as the target PDU session. For example, if the S-NSSAI to which the PDU session 1 belongs has a higher priority, and the S-NSSAI to which the PDU session 2 belongs has a lower priority, the network device can determine the PDU session 1 as the target. The PDU session, or the network device may determine that the priority of the PDU session 1 is higher than the priority of the PDU session 2. In the absence of other higher priority PDU sessions, the network device may determine the PDU session 1 as the target PDU session. .
  • the network device determines the post-established PDU session as the target PDU session according to the time of the session establishment, or the network device sets the priority of the later established PDU session.
  • the post-established PDU session with a higher priority is determined as the target PDU session.
  • the network device may determine the target PDU session according to the locally configured policy and the IP address version corresponding to the PDU session, for example, determining the PDU session with the IP address version v6 as the target PDU session, or the network device may according to the locally configured policy and The IP address version corresponding to the PDU session sets the priority of the PDU session.
  • the local policy is configured to preferentially switch the PDU session with the IP version of v6.
  • the network device may determine the priority of the PDU session according to the service type of the PDU session, determine the PDU session whose service type is voice as the target PDU session, or set the PDU session whose service type is voice to a higher priority.
  • the handover indication information may also be other indication functions, which is not limited by the embodiment of the present application.
  • the method further includes: acquiring, by the network device, handover indication information of the established PDU session of the terminal in the first network, where each PDU session in the established PDU session has the same data network name.
  • the switching indication information of the PDU session established by the network device in the first network may be obtained by using the following methods:
  • the network device receives handover indication information of a PDU session established by the terminal from the at least one control plane function network element in the first network. That is, each control plane function network element of at least one control plane function network element can obtain the handover indication information of the PDU session corresponding to each control plane function gateway. For example, each control plane function gateway can obtain the corresponding PDU sent by the terminal.
  • the handover indication information of the session, each control plane function network element may send the handover indication information of the corresponding PDU session determined by itself to the network device, or each control plane function network element may switch the corresponding PDU session sent by the terminal.
  • the indication information is adjusted to obtain the handover indication information of the adjusted PDU session, and then sent to the network device.
  • the network device may be an access and mobility management function device or a user data management network element, so that access and mobility management
  • the function device may determine the target PDU session in the established PDU session according to the handover indication information of the established PDU session, or the user data management network element may determine the target PDU in the established PDU session according to the handover indication information of the established PDU session. Conversation.
  • the network device is a user data management network element, for example, may be the foregoing HSS+UDM, or may be an access and mobility management function device.
  • the network device receives the auxiliary information of the first PDU session in the established PDU session sent by the first control plane function network element, and the network device determines, according to the auxiliary information, the handover indication information of the first PDU session.
  • the auxiliary information may be the aforementioned auxiliary information.
  • the switching indication information indicates that the switching priority of the PDU session is used for example. For example, the network device may determine that the priority of the corresponding PDU session with a higher S-NSSAI priority is higher, and the S-NSSAI has a lower priority.
  • the priority of the corresponding PDU session is determined to be lower.
  • the network device sets the priority of the subsequently established PDU session to be higher than the previously established PDU session according to the time of the session establishment.
  • the network device can set the priority of the session according to the locally configured policy and the IP address version corresponding to the PDU session.
  • the local policy is configured to preferentially switch the PDU session with the IP version of v6.
  • the network device may determine the priority of the PDU session according to the service type of the first PDU session, set a higher priority of the PDU session whose service type is voice, and the like.
  • the method further includes: when the user data management network element, the user data management network element sends a handover indication of the first PDU session to the first control plane function network element information.
  • the first control plane function network element may send the handover indication information of the first PDU session to the terminal.
  • the network device is a user data management network element, for example, the foregoing HSS+UDM.
  • the user data management network element receives initial handover indication information of the second PDU session in the established PDU session sent by the second control plane function network element; the user data management network element adjusts the initial handover indication information Obtaining the handover indication information of the second PDU session; that is, the user data management network element may adjust the initial handover indication information of the second PDU session sent by the second control plane function network element, for example, the data management network element has been
  • the switching indication information of the PDU session 1 sent by the control plane function network element 1 is saved, and the data management network element receives the PDU session 2 (the second PDU session) sent by the control plane function network element 2 (second control plane function network element).
  • the handover indication information (initial handover indication information) is found, the handover indication information of PDU session 1 and PDU session 2 is found to be the same, and PDU session 1 and PDU session 2 have the same data network name, when PDU session 1 and PDU session 2 If the user plane function network element is different, the data management network element may adjust the handover indication information of the PDU session 2 to be different from the handover indication information of the PDU session 1.
  • the policy that is preset by the user data management network element, or the policy that is obtained according to the historical data, and the network device for example, adjusts the handover indication information of the PDU session 2 according to the foregoing auxiliary information, which is not limited in this embodiment of the present application.
  • the method further includes: the user data management network element sending the handover indication information of the second PDU session to the second control plane function network element. That is, the user data management network element sends the adjusted handover indication information of the second PDU session to the second control plane function network element.
  • the second control plane function network element may switch the second PDU session. The information is sent to the terminal.
  • the second control plane function network element may send the handover indication information of the second PDU session to the access and mobility management function device.
  • the network device is a user data management network element, for example, the foregoing HSS+UDM, and the user data management network element may determine handover indication information of each PDU session of the established PDU session. That is, the user data management network element can determine the handover indication information of each PDU session according to the subscription data of each PDU session and the local policy.
  • the local policy may be the aforementioned handover indication information for determining each PDU session based on the auxiliary information.
  • the manner in which the network device obtains the handover indication information of each PDU session in the handover indication information of the establishment of the PDU session may be one of the foregoing four manners, and optionally, the manner of acquiring the handover indication information of each PDU. If the PDU session is a plurality of PDU sessions, the manner of obtaining the handover indication information of the at least two PDU sessions may be different. For example, two of the foregoing four manners are used.
  • the network device sends the session information of the target PDU session to the mobility management entity device of the second network, so that the mobility management entity device of the second network determines the target PDU according to the session information of the target PDU session. Session information for the session.
  • the session information of the target PDU session includes an identifier of a control plane function network element corresponding to the target PDU session and a data network name of the target PDU session, such that the mobility management entity device of the second network Determining, by the identifier of the corresponding control plane function network element of the target PDU session, the control plane function network element corresponding to the target PDU session, and the mobility management entity device of the second network transparently transmitting the identifier of the target PDU session sent by the terminal to the target
  • the control plane function network element corresponding to the PDU session, the control plane function network element corresponding to the target PDU session searches for the target PDU session according to the identifier of the target PDU session, and if found, performs switching of the target PDU session.
  • the first network may be a 5G network and the second network may be a 4G network.
  • the network device may be an access and mobility management function entity, for example, may be the AMF in FIG. 1; optionally, the network device may be a user data management network element, for example, may be in the foregoing FIG. HSS+UDM.
  • the device in this application does not limit the specific device of the network device.
  • the target PDU session is used as a PDU session for switching to the second network, and the PDU session of the terminal in the PDU session established by the first network except the target PDU session may be released.
  • the network device may determine the target PDU session in the PDU session established by the terminal in the first network according to the handover indication information, so that the target PDU session may be as capable of switching to the second network.
  • the PDU session can prevent the uncontrollable situation caused by the terminal switching to the same control plane function network element of the second network when the PDU session established by the first network is switched, which helps control the switching of the PDU session, thereby improving system performance. .
  • FIG. 3 shows a communication method 300 provided by an embodiment of the present application.
  • the method 300 includes:
  • the terminal acquires handover indication information of a protocol data unit PDU session established in the first network, where each PDU session in the establishment PDU session has the same data network name DNN.
  • the PDU session established in the first network may be one or more.
  • the handover indication information of the established PDU session may include: corresponding handover indication information may exist in each PDU session in the established PDU session, and the handover indication information may be the same or different in the established PDU sessions. PDU session. Or at least one PDU session in the established PDU session has corresponding handover indication information.
  • the handover indication information may indicate whether the PDU session can be switched. For example, only one PDU session in the three PDU sessions can be switched.
  • the handover indication information of the PDU session indicates that the PDU session can be switched, and whether the remaining two PDU sessions can be switched can be omitted, and cannot be switched by default.
  • the terminal obtains the handover indication information of the PDU session established in the first network, and the following manners are available:
  • the terminal determines handover indication information of the established PDU session. For example, the terminal determines the handover indication information of the at least one PDU session according to the local policy, where the local policy may determine the handover indication information of the established PDU session according to the S-NSSAI of the PDU session with the same DNN, for example, an S-NSSAI is in the S-NSSAI. If the priority of the PDU session is the highest, the priority of the PDU session is the highest, or the switching indication information of the PDU session can be determined according to the service type carried by the PDU session, or the PDU is determined according to the combination of the two. The switching instruction of the session.
  • the terminal when the terminal determines the handover priority of the PDU session established in the first network according to the S-NSSAI, as shown in Table 1, the terminal can configure the S-NSSAI and the handover priority. Correspondence relationship, as shown in Table 2, the terminal can configure the correspondence between the service type and the handover priority.
  • the terminal may not change the handover indication information of the previously established PDU session when determining the handover indication information of the PDU session established after the handover. For example, the terminal determines the handover indication information of the PDU session according to the determined rule.
  • the terminal determines whether the PDU session is switchable.
  • the terminal may determine that the PDU session is switchable according to the S-NSSAI corresponding to the PDU session.
  • the terminal changes the handover indication information of the previously established PDU session when determining the handover indication information of the PDU session established after the terminal determines.
  • the terminal first establishes a PDU session in the network slice corresponding to the S-NSSAI4.
  • the PDU session is the first PDU session corresponding to the DNN, and the terminal determines that the PDU session can be switched. After that, the terminal establishes a new PDU session in the network slice corresponding to the S-NSSAI1.
  • the terminal Since the priority of the S-NSSAI1 is higher than that of the S-NSSAI4, the terminal sets the PDU session in the S-NSSAI1 to be switchable. Set the previously established PDU session in S-NSSAI4 to be non-switchable. For example, when the terminal establishes a new PDU session of the SSC mode 2, the terminal sets the new PDU session to be switchable, and sets the PDU session of the SSC mode 2 of the same DNN that was previously established to be non-switchable or the like.
  • the terminal may send the handover indication information of the PDU session to the corresponding control plane function network element for each of the handover indication information of the PDU session.
  • the handover indication information of the newly established PDU session affects the handover indication information of the established PDU session
  • the newly established PDU session is determined by the terminal to be switchable, thereby causing the previously established PDU session of the same DNN to be determined.
  • the terminal sends the switching indication information of the newly established PDU session to the control plane function network element, and sends it to the HSS+UDM by the control plane function network element.
  • the HSS+UDM sets the handover indication information of the PDU session that was previously determined to be the switchable DNN to be non-switchable, and notifies the control plane function network element corresponding to the PDU session.
  • the terminal receives handover indication information from the established PDU session sent by at least one control plane function network element.
  • the at least one control plane function network element may send the handover indication information of the corresponding PDU session determined by itself to the terminal.
  • the control plane function network element determines the handover indication information of the PDU session according to the auxiliary information of the PDU session, and determines the PDU.
  • the method of determining the handover indication information of the PDU session according to the auxiliary information of the PDU session refer to the description in the method 200, or at least one control plane function network element in the control plane function network element may be used.
  • the switching indication information corresponding to the self PDU session is not limited.
  • the terminal sends the initial handover indication information of the first PDU session to the second control plane function network element, where the initial handover indication information is used to determine handover indication information of the first PDU session;
  • the terminal receives the handover priority information of the first PDU session sent by the second control plane function network element.
  • the terminal sends the initial handover indication information of the first PDU session determined by the terminal to the second control plane function network element
  • the second control plane function network element can adjust the initial handover indication information of the first PDU session sent by the terminal, for example,
  • the second control plane function network element has determined the handover indication information of the PDU session 1, and the second control plane function network element receives the handover indication information of the PDU session 2 (the first PDU session) sent by the terminal, and the second control plane
  • the function network element determines that the PDU session 1 and the PDU session 2 belong to the same second control plane function network element and the same user plane function control network element, and the second control plane function network element discovers the handover indication of the PDU session 1 and the PDU session 2.
  • the second control plane function network element adjusts the initial handover indication information of the PDU session 2 to the handover indication information of the PDU session 1. That is, the second control plane function network element can adjust the handover indication information of the PDU session sent by the terminal according to the handover indication information of the PDU session sent by the terminal and the handover indication information of the PDU session saved by the terminal. For another example, the second control plane function network element has determined the handover indication information of the PDU session 1.
  • the second control plane function network element When the second control plane function network element receives the handover indication information of the PDU session 2 sent by the terminal, the handover indication information of the PDU session 1
  • the switch indication information of the PDU session 2 is the same, but the user plane function network element of the PDU session 1 and the PDU session 2 are different, and the second control plane function network element adjusts the handover indication information of the PDU session 2 to be different from the PDU session.
  • the handover indication information of 1 for example, when the handover indication information is used to indicate the priority of the PDU session, the priority of the PDU session 2 may be adjusted to be lower or higher than the priority of the PDU session 1.
  • the strategy for adjusting and adjusting the embodiment of the present application is not limited.
  • the first control plane function network element is the second control plane function network element.
  • the terminal determines a target PDU session in the established PDU session according to the handover indication information.
  • the target PDU session may be one or more, which is not limited in this embodiment of the present application.
  • the handover indication information is used to indicate a handover priority of each PDU session in the established PDU session, where S320 includes: the terminal has the highest handover priority in the established PDU session.
  • the PDU session is determined to be the target PDU session. For example, if there is one PDU session with the highest priority, the one PDU session is the target PDU session, and the PDU session with the highest priority is more than two. The two or more PDU sessions are the target PDU session. Specifically, the concept of switching priorities is described in the method 200.
  • the handover indication information is used to indicate whether each PDU session in the established PDU session can be switched.
  • the handover indication information may be an indication domain, for example, the reference time domain of a certain PDU session is 1. Indicates that the PDU session can be switched.
  • the indication field of a PDU session is 0, indicating that the PDU session cannot be switched.
  • the S320 includes: the terminal determining, by the terminal, the switchable PDU session indicated by the handover indication information. Target PDU session. That is, the handover indication information indicates that the PDU session that can be switched is one, and the PDU session is the target PDU session. If the handover indication information indicates that there are multiple PDU sessions that can be switched, the multiple PDU sessions may be the target PDU session.
  • the multiple target PDU sessions may correspond to the same control plane function gateway and user plane function network element.
  • the control plane function network element may be SMF+PGW-C
  • the user plane function network element may be UPF+PGW-U. .
  • the terminal sends the identifier of the target PDU session to the first control plane function network element via the mobility management entity device of the second network.
  • the method includes: the terminal sending, to the mobility management entity device, an identifier of the target PDU session and a DNN of the target PDU session, where a DNN of the target PDU session is used for the
  • the mobility management entity device determines the first control plane function network element, so that the mobility management entity device sends the identifier of the target PDU session to the first control plane function network element. That is, the terminal may send the identifier of the target PDU session and the data network name of the target PDU session to the mobility management entity device of the second network, where the mobility management entity device of the second network may determine the data network name according to the target PDU session.
  • the first control plane function network element corresponding to the target PDU session specifically, the user data management network element may send the identifier of the control plane function network element corresponding to each data network name to the mobility management entity device of the second network, After receiving the identifier of the control plane function network element corresponding to each data network name sent by the user management network element, the mobility management entity device of the second network searches for the target PDU session according to the data network name of the target PDU session sent by the terminal.
  • the first control plane function network element, the mobility management entity device of the second network may send the identifier of the target PDU session to the first control plane function network element, so that the first control plane function network element can be based on the target PDU
  • the identity of the session determines the PDU session that needs to be switched, for example, the mobility management of the second network Equipment can be MME.
  • the user management network element determines the target PDU session under each DNN (the highest priority PDU session or a PDU session capable of switching, and transmitting the DNN 1 and the control plane function network element 1 corresponding to the DNN 1 to the mobility management entity of the second network (the PDU session corresponding to the control plane function network element 1 is the target PDU session, the target The data network name of the PDU session is DNN1), and the DNN 2 and the control plane function network element 2 corresponding to the DNN 2 are also sent.
  • DNN the highest priority PDU session or a PDU session capable of switching
  • the PDU session corresponding to the control plane function network element 2 is the target PDU session, and the data network name of the target PDU session.
  • the mobility management of the second network can determine that the DNN 1 corresponds to the control plane function network element 1, and the mobility management device of the second network can send the control plane function network element 1 (the first control plane function network element) The identity of the target PDU session, such that the control plane function network element 1 can determine the target PDU session to be handed over.
  • the terminal sends the identifier of the target PDU session and the data network name of the target PDU session to the mobility management entity device, including: the terminal to the mobility management entity device Sending a first request message, where the first request message carries an identifier of the target PDU session and a data network name of the target PDU session, where the first request message is an attach request message or a session establishment request message. That is, after the terminal determines the target PDU session, the identifier of the target PDU session and the data network name of the target PDU session may be carried when the attach request message is sent to the mobility management entity device of the second network, or may be carried in the session establishment request message. The identity of the target PDU session and the data network name of the target PDU session.
  • the embodiment of the present application does not limit the manner in which the terminal sends the identifier of the target PDU session to the mobility management entity device of the second network and the data network name of the target PDU session.
  • FIG. 4 shows a communication method 400 provided by an embodiment of the present application.
  • the method 400 includes:
  • the terminal sends, to the mobility management entity device of the second network, a first data network name corresponding to the current PDU session.
  • the mobility management entity device of the second network can determine the control plane function network element corresponding to the current PDU session.
  • the mobility management entity device of the second network may send a PDU session (current PDU session) update request corresponding to the first network name to the control plane function network element, and the control plane function network element receives the session update corresponding to the first data network name.
  • the control plane function network element obtains the PDU session corresponding to the first data network name according to the first data network name. If the corresponding PDU session is one, the PDU session is the session that needs to be switched.
  • the control plane function network element selects a PDU session as the PDU session to be switched.
  • the control plane function network element may select one PDU session as the PDU session to be switched, or determine the PDU session to be switched according to the auxiliary information of the PDU session, for example, determine the PDU session to be switched according to the S-NSSAI corresponding to the session, or If the SSC mode of the PDU session is 3, the PDU session to be switched is determined according to the time of establishing the PDU session, or the PDU session to be switched is determined according to the IP address version of the PDU session.
  • control plane function network element may also query the session identifier of the PDU session to be switched from the user data management network element, and determine the PDU session to be switched according to the session identifier of the PDU session to be switched. Make a limit. .
  • the S410 may include: the terminal sending an attach request message or a session establishment request message to the mobility management entity device of the second network, where the attach request message or the session establishment request message carries the first data network name corresponding to the current PDU session. .
  • the control plane function network element is attached after determining the PDU session that needs to be switched. In the process, the PDU session is switched to the PDN connection. If the terminal carries the data network name corresponding to the current PDU session in the session establishment request message, the control plane function network element is in the process of the session establishment request after determining the PDU session to be switched. Switch the PDU session to a PDN connection. After the handover is completed, the control plane function network element sends the identifier of the PDU session that has been switched to the terminal. For example, the control plane function network element sends a protocol configuration option (PCO) to the terminal, and the PCO carries the identifier of the PDU session that has been switched.
  • PCO protocol configuration option
  • the terminal receives the identifier of the switched PDU session sent by the control plane function network element, and determines the PDU session that has been switched according to the identifier of the PDU session.
  • the terminal receives the PCO sent by the control plane function network element, obtains the identifier of the PDU session that has been switched in the PCO, and determines the PDU session that has been switched according to the identifier of the PDU session, so that the UE can connect the PDN and the corresponding The conversations are related.
  • FIG. 5 shows a communication method 500 provided by an embodiment of the present application.
  • the method 500 includes:
  • the first control plane function network element receives a session establishment request message sent by the terminal, where the session establishment request message is used to request to establish a first protocol data unit PDU session.
  • the first control plane function network element acquires handover indication information of the first PDU session.
  • the handover indication information is used to indicate a priority of the first PDU session or to indicate whether the first PDU session can be switched.
  • the first control plane function network element obtains the first handover indication information of the first PDU session in the following five manners.
  • the session establishment request message in S510 carries the handover indication information of the first PDU session.
  • the first control plane function network element may determine handover indication information of the first PDU session in the session establishment request message.
  • the first control plane function network element may send the handover indication of the first PDU session to the user data management network element.
  • the user data management network element receives the handover indication information corresponding to each PDU session in the plurality of PDU sessions (the plurality of PDU sessions have the same DNN) sent by the plurality of control plane function network elements, the user data management network element The saving may be performed, and the target PDU session is determined according to the handover indication information corresponding to each PDU session in the multiple PDU sessions when the terminal switches to the second network, that is, the PDU session that can be switched is determined.
  • the first control plane function network element may send the handover indication information of the first PDU session to the access and mobility management function device, where the access and mobility management function device receives multiple PDUs sent by multiple control plane function network elements After the handover indication information corresponding to each PDU session in the session (the plurality of PDU sessions have the same DNN), the access and mobility management function device may save and corresponding to each PDU session in the multiple PDU sessions at the time of handover
  • the handover indication information determines a target PDU session, ie, determines a PDU session that can be handed over.
  • the first control plane function network element may also send the DNN of the first PDU session and the identifier of the first control plane function network element to the user data management network element, where the first control plane function network element may manage the user data.
  • the network element sends the session information of the first PDU session, where the session information includes the handover indication information of the first PDU session, the DNN of the first PDU session, and the identifier of the first control plane control network element.
  • the user data management network element can save the session information of the first PDU session.
  • the user data management network element receives the session information of multiple PDU sessions (having the same DNN), according to the handover indication information of the multiple PDU sessions. Determining the target PDU session, and then transmitting the DNN of the target PDU session and the identifier of the control plane function network element corresponding to the target PDU session to the mobility management function entity device of the second network.
  • the first control plane function network element receives initial handover indication information of the first PDU session sent by the terminal, and the first control plane function network element adjusts the obtained information according to the initial handover indication information. Switching indication information of the first PDU session;
  • the first control plane function network element sends the handover indication information of the first PDU session to the terminal or the user data management network element or the access and mobility management function.
  • the first control plane function network element receives initial handover indication information of the first PDU session sent by the terminal, and the first control plane function network element performs initial handover indication information of the first PDU session.
  • the user data management network element adjusting the initial handover indication information of the first PDU session to obtain the handover indication information of the first PDU session; and the data data management network element switching the indication of the first PDU session The information is sent to the first control plane function network element.
  • the first control plane function network element sends the first handover indication information to the terminal or the access and mobility management function, and the first control plane function network element will be adjusted.
  • the handover indication information of a PDU session is sent to the terminal.
  • the first control plane function network element sends the auxiliary information of the first PDU session to the user data management network element; the data data management network element determines the first part according to the auxiliary information of the first PDU session. And switching the indication information of the first PDU session to the first control plane function network element, where the first control plane function network element receives the handover sent by the user data management network element
  • the switching instruction information of the first PDU session, the auxiliary information of the first PDU session includes an Internet Protocol IP address version corresponding to the first PDU session, and a single network slice assistance information corresponding to the first PDU session.
  • the session and service continuity SSC mode corresponding to the first PDU session, the allocation and reservation handover priority ARP corresponding to the first PDU session, the service type of the first PDU session, and the establishment of the first PDU session At least one of the times;
  • the method further includes: the first control plane function network element sending the first handover indication information of the first PDU session to the terminal or the access and mobility management function.
  • the first control plane function network element determines the second handover indication information of the first PDU session according to the local policy, and the first control plane function network element sends the first information to the user data management network element.
  • the second switching indication information is obtained by the user data management network element adjusting the second handover indication information to obtain the first handover indication information of the first PDU session, and the first handover indication information is sent to the first control plane function network element.
  • the terminal may receive multiple PDU sessions sent by multiple control plane function network elements (having the same The switching indication information of the DNN), the terminal may determine the target PDU session in the multiple PDU sessions according to the handover indication information of the multiple PDU sessions, and the terminal may adjust the identifier of the target PDU session and the DNN of the target PDU session to the mobility management function.
  • the physical device sends.
  • the first control plane function network element sends the handover indication information of the first PDU session to the user data management network element.
  • the first control plane function network element may perform the DNN of the first PDU session and the first control plane function.
  • the identifier of the network element is sent to the user data management network element, and the user data management network element can receive the switching indication information of multiple PDU sessions (having the same DNN) sent by multiple control plane function network elements, and the user data management network element can be based on
  • the switching indication information of the multiple PDU sessions determines the target PDU session in the multiple PDU sessions, and the user data management network element maps the DNN of the target PDU session and the identifier of the target PDU session corresponding control plane function network element to the mobility management function entity.
  • the device sends.
  • the first control plane function network element sends the handover indication information of the first PDU session to the access and mobility management function.
  • the first control plane function network element may use the DNN of the first PDU session and the first control.
  • the identifier of the surface function network element is sent to the access and mobility management function, and the access and mobility management function can receive the handover indication information of multiple PDU sessions (with the same DNN) sent by multiple control plane function network elements,
  • the ingress and mobility management function may determine a target PDU session in the plurality of PDU sessions according to the handover indication information of the multiple PDU sessions, and the access and mobility management function associates the DNN of the target PDU session with the control plane function of the target PDU session.
  • the identifier of the network element is sent to the mobility management function entity device of the second network.
  • the first control plane function network element may be any A control plane function network element, in the method 200 to the method 500, does not indicate the same device, that is, in the embodiment of the present application, "first" and “second” do not specifically refer to a certain one, but Refers to any one.
  • the terminal is the UE
  • the access and mobility management function device is the AMF
  • the mobility management device is the MME
  • the control plane function network element is the SMF+PGW-C
  • the user data management network element is the HSS+
  • the first network is a 5G network
  • the second network is a 4G network.
  • the handover indication information indicates that the handover priority is used as an example.
  • the embodiment of the present application is not limited thereto.
  • the handover indication information may indicate a handover priority
  • the terminal switches from the 5G system to the evolved packet network system (EPS)
  • the handover indication information corresponding to the same PDU session of the DNN is determined to be switched to EPS PDU session.
  • the UE sends a handover priority to the SMF+PGW-C, which can determine the final handover priority and send back to the UE. If the same SMF+PGW-C and the same UPF+PGW-U serve the same PDU session of multiple DNNs, the SMF+PGW-C can set the priority of multiple PDU sessions to the same value.
  • the SMF+PGW-C sends the handover priority, the DNN, and the SMF+PGW-C ID to the UDM+HSS.
  • the UE moves to the EPS, the UE selects the PDU session with the highest priority. And sending a PDN connection setup request message to the MME, and carrying the ID of the PDU session in the PCO.
  • the HSS+UDM sends the SMF+PGW-C ID with the highest handover priority to the MME, thereby switching the PDU session with the highest handover priority to the corresponding PDN connection in the EPS.
  • the SMF+PGW-C sends the handover priority to the AMF along with the session context.
  • the AMF selects the PDU session with the highest handover priority and forwards the context of the PDU session to the MME.
  • the PDU session with the highest handover priority will be switched to EPS accordingly.
  • the UE may determine the handover priority when the PDU session is established, e.g., determine the handover priority in accordance with the manner in method 300.
  • the handover priority may be determined by the UE, and the handover priority may also be determined by SMF+PGW-C and/or HSS+UDM.
  • the SMF+PGW-C may first determine whether the PDU session can be handed over to the 4G network.
  • the SMF+PGW-C may determine that the PDU session does not need to be switched to 4G network.
  • SMF+PGW-C registers SMF+PGW-C ID and DNN with HSS+UDM
  • SMF+PGW-C can indicate whether the PDU session can be switched to 4G network.
  • SMF+PGW-C can use other auxiliary information. Sent to the HSS+UDM, for example, the S-NSSAI of the PDU session, the version of the IP address, the SSC mode, the ARP, the service type, and the setup time, etc., so that the HSS+UDM determines the handover priority based on the assistance information.
  • the HSS+UDM determines the handover priority of the multiple PDU sessions according to the handover assistance information, for example, for the SSC mode 3
  • HSS+UDM can mark the latest PDU session of the same DNN with higher priority.
  • HSS+UDM can configure default policy to select PDU session and so on.
  • the UE For a scenario where there is no N26 reception, when the UE moves to the EPS, the UE carries only the DNN in the PDN session establishment request message sent to the MME, and the UE does not select the PDU session to be switched. Therefore, the UE does not carry the PDU session ID in the PCO.
  • the HSS+UDM can send the SMF+PGW-C ID corresponding to the highest priority PDU session to the MME.
  • the SMF+PGW-C can indicate the DNN to the terminal through the PCO.
  • the ID of the established PDU session such that the UE can associate the PDN connection with the corresponding session.
  • AMF can determine the session that can be switched to 4G in a similar way to HSS+UDM.
  • Figure 6 to Figure 9 show the scenario where the N26 interface is deployed.
  • Figure 10 to Figure 13 show the scenario where the N26 interface is deployed.
  • FIG. 6 shows a communication method 600 provided by an embodiment of the present application, including:
  • the UE determines, when the PDU session is established on the 5G network, the handover indication information of the PDU session, where each PDU session in the established PDU session has the same DNN.
  • the switching indication information of the PDU session is a handover priority or indicates whether the PDU session can be switched.
  • the method for the UE to determine the handover indication information of the PDU session refer to 300.
  • the UE sends the handover indication information of the established PDU session to the AMF in the session establishment request message, or the session establishment request message includes a PCO, and the UE may carry the handover indication information of the established PDU session on the PCO.
  • the UE may send the handover indication information of each PDU session to the AMF through the session establishment request message to the AMF after determining the handover indication information of one PDU session.
  • the AMF receives the session establishment request message sent by the UE, and does not parse the handover indication information of the PDU session included in the session establishment request message, and directly forwards the information to the SMF+PGW through a non-access stratum (NAS) message.
  • C that is, a session establishment request message carries a PCO, and the PCO includes handover indication information of the PDU session.
  • SMF+PGW-C only one SMF+PGW-C is shown in FIG. 6, and multiple SMFs may be used in the actual application process.
  • +PGW-C that is, the AMF sends the handover indication information of the PDU session corresponding to each SMF+PGW-C to the corresponding SMF+PGW-C.
  • the SMF+PGW-C receives the non-access stratum message sent by the AMF, and obtains the handover indication information of the PDU session in the non-access stratum message.
  • the SMF+PGW-C can switch the received PDU session.
  • the indication information is adjusted and the handover indication information of the final PDU session is determined.
  • the SMF+PGW-C receives the handover indication information of the PDU session 1 and the PDU session 2 sent by the terminal, and the handover indication information of the PDU session 1 and the PDU session 2 sent by the terminal is different, and the UPF+ of the PDU session 1 and the PDU session 2 are different.
  • the SMF+PGW-C can adjust the handover indication information of the PDU session 1 and the PDU session 2 to be the same; for example, the handover indication information of the PDU session 1 and the PDU session 2 sent by the terminal is the same, and the PDU session is the same. 1 Unlike the UPF+PGW-U of the PDU Session 2, the SMF+PGW-C can adjust the handover indication information of the PDU Session 1 and the PDU Session 2 to be different.
  • S605 When the SMF+PGW-C does not adjust the handover indication information of the PDU session, directly send the session information of the received PDU session to the HSS+UDM, where the session information of the PDU session includes the handover indication information of the PDU session, and the SMF+
  • the identifier of the PGW-C and the DNN of the PDU session for example, the identifier of the SMF+PGW-C may be the SMF+PGW-C ID; after the SMF+PGW-C adjusts the handover indication information of the PDU session, the adjusted handover is performed.
  • the indication information, the identity of the SMF+PGW-C, and the DNN of the PDU session are sent to the HSS+UDM.
  • the DNN herein may be known by the SMF+PGW-C or sent by the terminal to the SMF+PGW-C, which is not limited in this embodiment of the present application.
  • the HSS+UDM receives the session information of the PDU session established by the terminal sent by the at least one SMF+PGW-C after the PDU session established by the 5G network, and stores the session information of the established PDU session.
  • the HSS+UDM checks other PDU sessions of the same DNN, if the HSS+UDM is saved. For other PDU sessions of the same DNN, and one of these other PDU sessions has been identified as switchable to the 4G network, the HSS+UDM determines which of the two switchable PDU sessions can switch to the 4G network. The HSS+UDM can determine which PDU session is switchable based on the assistance information (see the aforementioned assistance information).
  • the HSS+UDM determines that the previously established PDU session that has been indicated as switchable becomes non-switchable, the HSS+UDM notifies the SMF+PGW-C corresponding to the PDU session, and the SMF+PGW-C sets the PDU session to be unavailable. Switch.
  • the HSS+UDM may return response information to the at least one SMF+PGW-C for indicating that the session information of the PDU session sent by the SMF+PGW-C is accepted.
  • S608 SMF+PGW-C performs PDU session establishment, and SMF+PGW-C creates a context and sends it to AMF.
  • S609, the UE, the access network element, the AMF, the SMF+PGW-C, and the like perform a subsequent PDU session establishment process. This step is a prior art and is not described in detail herein.
  • S610 if the SMF+PGW-C modifies the handover indication information of the PDU session, sends the modified handover indication information to the terminal, and if the SMF+PGW-C does not modify the handover indication information of the PDU session, returns a confirmation to the terminal.
  • the message is used to indicate that the handover indication information sent by the UE is accepted.
  • the acknowledgment message may still carry the PDU session sent by the UE to the SMF+PGW-C. Switching indication information.
  • the UE determines a target PDU session according to the handover indication information of the multiple PDU sessions of the same DNN, where the target PDU session is that the UE desires to switch to 4G. PDU session.
  • the handover indication information is a handover priority
  • the UE determines the highest priority PDU session among the plurality of PDU sessions of the same DNN as the target PDU session.
  • the handover indication information is capable of handover, the UE determines that the "switchable" to 4G PDU session indicated by the handover indication information is the target PDU session.
  • the UE sends a first request message to the MME, where the first request message carries the ID of the target PDU session and the DNN of the target PDU session.
  • the first request message may be an attach request message or a PDN session setup request message.
  • the ID of the target PDU session is included in the PCO.
  • the MME sends a second request message to the HSS+UDM for requesting session information to the HSS+UDM, where the session information may include the DNN and the DNN.
  • the session information may include the DNN and the DNN.
  • the HSS+UDM determines, according to the session information of the saved PDU session, the PDU session that can be switched in the DNN in the different PDU session of the same DNN according to the handover indication information of the different PDU session of the same DNN, that is, the DNN corresponding to the DNN.
  • the target PDU session and determine the SMF+PGW-C ID corresponding to the target session.
  • the handover indication information is a handover priority
  • the HSS+UDM determines the highest priority PDU session among the plurality of PDU sessions of the same DNN as the target PDU session.
  • the handover indication information is capable of handover, the HSS+UDM determines that the "switchable" to 4G PDU session indicated by the handover indication information is the target PDU session.
  • the HSS+UDM sends the DNN of the target PDU session corresponding to the DNN and the SMF+PGW-C ID to the MME. That is, the HSS+UDM holds the session information of the PDU session of the plurality of DNNs, and the HSS+UDM can determine the target PDU session under each DNN and the SMF+PGW-C ID corresponding to the target PDU session under each DNN. Then, the DNN of the target PDU session under each DNN and the SMF+PGW-C ID corresponding to the target PDU session are sent to the MME. For example, the MME receives the DNN1 corresponding SMF+PGW-C1 and the DNN2 corresponds to the SMF+PGW-C. 2.
  • the MME sends a session establishment request message to the SMF+PGW-C.
  • the session establishment request message includes a PCO, where the PCO carries the ID of the target PDU session and the DNN of the target PDU session.
  • the SMF+PGW-C determines the PDU session to be switched according to the ID of the target PDU session sent by the MME and the DNN of the target PDU session, and if the SMF+PGW-C saves the DNN and the session corresponding to the DNN, the election is performed. The PDU session is switched. If the SMF+PGW-C finds that the target PDU session does not exist, the PDU session is rejected.
  • FIG. 7 shows a communication method 700 provided by an embodiment of the present application, including:
  • the UE sends a session establishment request message to the AMF.
  • the AMF sends a session establishment request message to the SMF+PGW-C.
  • the SMF+PGW-C determines handover indication information of the PDU session.
  • the SMF+PGW-C may determine handover indication information of the PDU session according to the foregoing auxiliary information.
  • the SMF+PGW-C may send the auxiliary information to the HSS+UDM, and the HSS+UDM adjusts the conflict according to the auxiliary information when it finds that there is a conflict between the handover indication information from the different SMF+PGW-C.
  • the HSS+UDM may adjust the handover indication information of the PDU session, and assume that the HSS+UDM has received the priority of the PDU session 1 from the first SMF+PGW-C to be 2, when the HSS+UDM receives the first
  • the PDU session 2 sent by the second SMF+PGW-C also has a priority of 2
  • the PDU session 1 and the PDU session 2 have the same DNN
  • the HSS+UDM can adjust the PDU session 1 and/or the PDU session 2 according to the auxiliary information.
  • priority For example, the HSS+UDM can adjust the priority of the PDU Session 2 to be higher or lower than the priority of the PDU Session 1.
  • the HSS+UDM stores the session information of the PDU session.
  • the HSS+UDM sends a response message to the SMF+PGW-C, indicating that the handover indication information of the PDU session sent by the SMF+PGW-C is accepted, optionally In the response message, the handover indication information of the accepted PDU session may be carried; if the HSS+UDM adjusts the handover indication information of the PDU session, the SMF+PGW-C sends the adjusted handover of the PDU session in the response message. Instructions.
  • S708-S718 is the same as S608 to S618.
  • FIG. 8 shows a communication method 800 provided by an embodiment of the present application, including:
  • the SMF+PGW-C sends the auxiliary information, the SMF+PGW-C ID, and the DNN of the PDU session to the HSS+UDM, which may be the auxiliary information in the foregoing method.
  • the HSS+UDM determines handover indication information of the PDU session according to the received auxiliary information.
  • the HSS+UDM stores handover indication information of the PDU session, an SMF+PGW-C ID, and a DNN of the PDU session.
  • the HSS+UDM sends a response message to the SMF+PGW-C, where the response message carries the indication information of the PDU session.
  • the HSS+UDM here may receive the PDU session assistance information SMF+PGW-C ID sent by multiple SMF+PGW-Cs, and the DNN of the PDU session.
  • the HSS+UDM sends the determined handover indication information of the PDU session corresponding to each SMF+PGW-C to the corresponding SMF+PGW-C.
  • S807-S817 is the same as S708-S718.
  • FIG. 9 shows a communication method 900 provided by an embodiment of the present application, including:
  • S910 in method 900 may be the same as S701-S709 in method 700, or S801-S808 in method 800, where only the steps subsequent to S910 in method 900 are described.
  • the UE When the UE moves to the 4G network, the UE sends a first request message to the MME, where the first request message carries the DNN of the current PDU session, and the first request message may be an attach request message or a session establishment request message.
  • the MME sends a session establishment request message to the SMF+PGW-C, where the session establishment request message carries the DNN of the current PDU session.
  • the SMF+PGW-C determines the PDU session as the switched PDU session, and if there are more PDU sessions corresponding to the DNN belonging to the SMF+PGW-C Then, the SMF+PGW-C can determine one PDU session among the plurality of PDU sessions as the switched PDU session.
  • the SMF+PGW-C sends the identifier of the switched PDU session to the UE, so that the UE is associated with the PDN connection according to the identifier of the PDU session.
  • the identifier of the PDU session is sent to the UE through the PCO.
  • the communication method when the N26 interface is not deployed between the MME and the AMF is shown in FIG. 6 to FIG. 9 .
  • the communication method between the MME and the AMF deployment N26 interface is described below with reference to FIG. 10 to FIG. 13 .
  • FIG. 10 shows a communication method 1000 provided by an embodiment of the present application, including:
  • the SMF+PGW-C stores handover indication information of the PDU session.
  • SMF+PGW-C sends a session establishment response message to the AMF.
  • TAU tracking area update
  • the MME After receiving the TAU request message, the MME sends a first context request message to the AMF, where the MME requests the AMF to send the context information of the UE to the MME, where the context information of the UE includes a session context.
  • the AMF After receiving the first context request message sent by the MME, the AMF sends a second context request message to the SMF+PGW-C according to the first context request message, for requesting the session context from the SMF+PGW-C.
  • the SMF+PGW-C sends the session information of the PDU session that can be switched to the 4G, and the session information includes the handover indication information of the PDU session, the default bearer identifier of the PDN connection corresponding to the PDU session, and the PDU session.
  • Information such as DNN and SMF+PGW-C ID.
  • the AMF may receive session information of a PDU session sent by each SMF+PGW-C of the multiple SMF+PGW-C, and the AMF may determine the target PDU session as the switched PDU in the PDU session of the same DNN in the session information. Conversation.
  • the AMF sends the session information of the target PDU session to the MME.
  • S1014, the MME, the AMF, the UE, and the like perform a subsequent handover process.
  • This step is a prior art, and the embodiment of the present application is not described in detail herein.
  • FIG. 11 shows a communication method 1100 provided by an embodiment of the present application, including:
  • S1101-S1107 is the same as S1001-S1007.
  • S1108 When the UE is in the data connection state, when the gNB finds that the location of the UE changes, the gNB sends a handover request to the AMF to request that the current PDU session needs to be switched.
  • the AMF sends a context request message to the SMF+PGW-C to obtain the context of the UE.
  • FIG. 12 shows a communication method 1200 provided by an embodiment of the present application, including:
  • the steps subsequent to S1204 in method 1200 may be the same as S1008-S1014 in method 1000, or the same as S1106-S1113 in method 1100, where only the steps prior to S1204 in method 1200 are described.
  • the SMF+PGW-C determines the handover indication information of the PDU session according to the auxiliary information of the PDU session.
  • the auxiliary information may be the foregoing auxiliary information.
  • FIG. 13 shows a communication method 1300 provided by an embodiment of the present application, including:
  • the steps subsequent to S1305 in method 1300 may be the same as S1006-S1014 in method 1000, or may be the same as S1106-S1113 in method 1100, where only the steps prior to S1305 in method 1300 are described.
  • the SMF+PGW-C sends a session registration request message to the HSS+UDM, where the registration request message includes auxiliary information, and the auxiliary information may be the foregoing auxiliary information.
  • the HSS+UDM receives the registration request message sent by the SMF+PGW-C, obtains the auxiliary information in the registration request message, and determines the handover indication information of the PDU session according to the auxiliary information. In this way, the HSS+UDM can determine the handover indication information of the PDU session corresponding to multiple SMF+PGW-Cs.
  • the HSS+UDM sends the handover indication information of the PDU session corresponding to each SMF+PGW-C to the corresponding SMF+PGW-C through the response message of the session registration request message.
  • sequence of the steps in the foregoing method 200 to method 1300 is not limited in any way, and the sequence numbers in each method do not represent the sequence, and the steps in each method may be used in practical applications.
  • the order is adjusted, for example, the order of the steps in each method can be determined according to the intrinsic logic.
  • FIG. 14 shows a communication device 1400 provided by an embodiment of the present application.
  • the device 1400 may be the foregoing network device.
  • the network device may be a user data management network element or an access and mobility management function device.
  • the device 1400 includes:
  • the processing unit 1410 is configured to determine, in the established PDU session, a target PDU session according to the handover indication information of the protocol data unit PDU session established by the terminal in the first network, where each PDU session in the established PDU session has The same data network name DNN;
  • the transceiver unit 1420 is configured to send session information of the target PDU session to the mobility management entity device of the second network.
  • the handover indication information is used to indicate a handover priority of each PDU session in the established PDU session, and the processing unit 1410 is specifically configured to: prioritize handover in the established PDU session.
  • the highest level PDU session is determined to be the target PDU session.
  • the handover indication information is used to indicate whether each PDU session in the established PDU session can be switched; the processing unit 1410 is specifically configured to: switchable in the handover indication information If there is only one PDU session, determining that the switchable PDU session is the target PDU session; in the case that the handover indication information indicates that there are at least two PDU sessions that can be switched, in the at least two PDU sessions Determining the target PDU session.
  • the processing unit 1410 is specifically configured to: if the at least two PDU sessions belong to the same control plane function network element, determine the at least two sessions as the target session; The two PDU sessions belong to different control plane function network elements, and the target PDU session is determined in the at least two PDU sessions according to the auxiliary information of each of the at least two PDU sessions of the at least two PDU sessions.
  • the device 1400 is a user data management network element
  • the transceiver unit 1420 is further configured to: in the switching instruction information according to the protocol data unit PDU session established by the terminal in the first network, Receiving auxiliary information of the first PDU session in the established PDU session sent by the first control plane function network element, before determining the target PDU session in the established PDU session;
  • the processing unit 1410 is further configured to: determine, according to the auxiliary information, handover indication information of the first PDU session.
  • the auxiliary information includes at least one of the following: an Internet Protocol IP address version corresponding to the PDU session, a single network slice assistance information corresponding to the PDU session, a session and service continuity SSC mode corresponding to the PDU session, and a PDU.
  • the transceiver unit 1420 is further configured to: determine, in the established PDU session, a target PDU session according to the handover indication information of the protocol data unit PDU session established by the terminal in the first network. Previously, receiving handover indication information of a PDU session established by the terminal from the at least one control plane function network element in the first network.
  • the device 1400 is a user data management network element
  • the transceiver unit 1420 is further configured to: in the switching instruction information according to the protocol data unit PDU session established by the terminal in the first network, Before determining the target PDU session in the established PDU session, receiving initial handover indication information of the second PDU session in the PDU session established by the terminal sent by the second control plane function network element in the first network; the processing unit 1410 The method further includes: adjusting the initial handover indication information to obtain handover indication information of the second PDU session; the transceiver unit 1420 is further configured to: send the second PDU session to the second control plane function network element Switch the indication information.
  • the session information of the target PDU session includes an identifier of a control plane function network element corresponding to the target PDU session and a DNN of the target PDU session.
  • the apparatus 1400 herein is embodied in the form of a functional unit.
  • the term "unit” as used herein may refer to an application specific integrated circuit (ASIC), an electronic circuit, a processor (eg, a shared processor, a proprietary processor, or a group) for executing one or more software or firmware programs. Processors, etc.) and memory, merge logic, and/or other suitable components that support the described functionality.
  • ASIC application specific integrated circuit
  • the device 1400 may be specifically the network device in the foregoing method embodiment, and the device 1400 may be used to perform various processes and/or steps corresponding to the terminal in the foregoing method embodiment. To avoid repetition, we will not repeat them here.
  • FIG. 15 shows a communication device 1500 provided by an embodiment of the present application.
  • the device 1500 may be the foregoing terminal, and the device 1500 includes:
  • the obtaining unit 1510 is configured to acquire handover indication information of a protocol data unit PDU session established in the first network, where each PDU session in the established PDU session has the same data network name DNN;
  • the processing unit 1520 is configured to determine, in the established PDU session, a target PDU session according to the handover indication information of the established PDU session.
  • the transceiver unit 1530 is configured to send, by using the mobility management entity device of the second network, the identifier of the target PDU session to the first control plane function network element.
  • the handover indication information is used to indicate a handover priority of each PDU session in the established PDU session, and the processing unit 1520 is specifically configured to: prioritize handover in the established PDU session.
  • the highest level PDU session is determined to be the target PDU session.
  • the handover indication information is used to indicate whether each PDU session in the established PDU session can be switched; the processing unit 1520 is specifically configured to: switch the PDU session to be established.
  • the PDU session is determined to be the target PDU session.
  • the transceiver unit 1530 is specifically configured to: send, to the mobility management entity device, an identifier of the target PDU session and a DNN of the target PDU session, where a DNN of the target PDU session is used.
  • the mobility management entity device determines the first control plane function network element, so that the mobility management entity device sends the identifier of the target PDU session to the first control plane function network element.
  • the transceiver unit 1530 is specifically configured to: send a first request message to the mobility management entity device, where the first request message carries an identifier of the target PDU session and the target PDU The DNN of the session, the first request message is an attach request message or a session establishment request message.
  • the acquiring unit 1510 is specifically configured to: receive handover indication information of the established PDU session sent by the at least one control plane function network element.
  • the transceiver unit 1530 is further configured to: send initial handover indication information of the first PDU session to a second control plane function network element, where the initial handover indication information is used to determine the first The switching indication information of the PDU session is received; the switching indication information of the first PDU session sent by the second control plane function network element is received.
  • the apparatus 1500 herein is embodied in the form of a functional unit.
  • the term "unit” as used herein may refer to an application specific integrated circuit (ASIC), an electronic circuit, a processor (eg, a shared processor, a proprietary processor, or a group) for executing one or more software or firmware programs. Processors, etc.) and memory, merge logic, and/or other suitable components that support the described functionality.
  • ASIC application specific integrated circuit
  • processor eg, a shared processor, a proprietary processor, or a group
  • memory merge logic, and/or other suitable components that support the described functionality.
  • the device 1500 may be specifically the terminal in the foregoing method embodiment, and the device 1500 may be used to perform various processes and/or steps corresponding to the terminal in the foregoing method embodiment. Avoid repetition and we will not repeat them here.
  • FIG. 16 shows a communication device 1600 provided by an embodiment of the present application.
  • the device 1600 may be the first control plane function network element, and the device 1600 includes:
  • the transceiver unit 1610 is configured to receive a session establishment request message sent by the terminal, where the session establishment request message is used to request to establish a first protocol data unit PDU session.
  • the obtaining unit 1620 is configured to acquire switching indication information of the first PDU session.
  • the handover indication information is used to indicate a priority of the first PDU session or to indicate whether the first PDU session can be switched.
  • the session establishment request message includes the handover indication information of the first PDU session
  • the obtaining unit 1620 is specifically configured to: acquire the first PDU session in the session establishment request message The indication information is switched; the transceiver unit 1610 is further configured to: send the handover indication information of the first PDU session to the user data management network element or the access and mobility management function device.
  • the acquiring unit 1620 is specifically configured to: obtain initial handover indication information of the first PDU session; the apparatus 1600 further includes: a processing unit, configured to acquire, according to the initial handover indication information, And the obtained handover instruction information of the first PDU session; the transceiver unit 1610 is further configured to: send the handover indication information of the first PDU session to the terminal or the user data management network element or the access and mobility management function device .
  • the transceiver unit 1610 is further configured to: send auxiliary information of the first PDU session to a user data management network element; and receive the first PDU session sent by the user data management network element.
  • the switching indication information, the handover indication information of the first PDU session is determined according to the auxiliary information of the first PDU session, and the auxiliary information of the first PDU session includes an Internet Protocol IP address version corresponding to the first PDU session, Single network slice assistance information corresponding to the first PDU session, session and service continuity SSC mode corresponding to the first PDU session, allocation and reservation handover priority ARP corresponding to the first PDU session, the first And at least one of a service type of the PDU session and a setup time corresponding to the first PDU session; and the handover indication information of the first PDU session is sent to the terminal or the access and mobility management function device.
  • the transceiver unit 1610 is further configured to: send a data network name DNN of the first PDU session and an identifier of the device to a user data management network element.
  • the apparatus 1600 herein is embodied in the form of a functional unit.
  • the term "unit” as used herein may refer to an application specific integrated circuit (ASIC), an electronic circuit, a processor (eg, a shared processor, a proprietary processor, or a group) for executing one or more software or firmware programs. Processors, etc.) and memory, merge logic, and/or other suitable components that support the described functionality.
  • ASIC application specific integrated circuit
  • the device 1600 may be specifically the first control plane function network element or the second control plane function network element in the foregoing method embodiment, and the apparatus 1600 may be configured to perform the foregoing method implementation.
  • the processes and/or steps corresponding to the first control plane function network element or the second control plane function network element are not repeated here.
  • the device 1400 is completely corresponding to the network device in the method embodiment, and the device 1500 is completely corresponding to the terminal in the method embodiment, and the first control plane function network element or the second control plane function network element in the foregoing device 1600 and the method embodiment Correspondingly, the corresponding steps are performed by the corresponding unit.
  • the transceiver unit method performs the transceiving step in the method embodiment, and the steps other than transceiving may be performed by the processing module.
  • the processing module For the function of the specific module, reference may be made to the corresponding method embodiment, which is not described in detail.
  • the device 1400-device 1600 of each of the above solutions has the function of implementing the corresponding steps performed by the network device, the terminal, the first control plane function network element or the second control plane function network element in the above method; the function can be implemented by hardware,
  • the corresponding software implementation can be performed by hardware.
  • the hardware or software includes one or more modules corresponding to the above functions; for example, the transmitting unit may be replaced by a transmitter, the receiving unit may be replaced by a receiver, and other units such as a determining unit may be replaced by a processor and executed separately Transceiver operations and associated processing operations in various method embodiments.
  • the device in FIG. 14-16 may also be a chip or a chip system, for example, a system on chip (SoC).
  • the receiving unit and the sending unit may be transceiver circuits of the chip, which are not limited herein.
  • FIG. 17 shows still another communication device 1700 provided by an embodiment of the present application.
  • the apparatus 1700 includes a processor 1710, a transceiver 1720, and a memory 1730.
  • the processor 1710, the transceiver 1720, and the memory 1730 communicate with each other through an internal connection path.
  • the memory 1730 is configured to store instructions, and the processor 1710 is configured to execute instructions stored by the memory 1730 to control the transceiver 1720 to send signals and / or receive signals.
  • the processor 1710 is configured to determine, in the established PDU session, a target PDU session according to the handover indication information of the protocol data unit PDU session established by the terminal in the first network, where each PDU session in the established PDU session Having the same data network name DNN; the transceiver 1720 is configured to send session information of the target PDU session to the mobility management entity device of the second network.
  • the device 1700 may be specifically the network device in the foregoing method embodiment, and may be used to perform various steps and/or processes corresponding to the network device in the foregoing method embodiment.
  • the memory 1730 can include read only memory and random access memory and provides instructions and data to the processor. A portion of the memory may also include a non-volatile random access memory.
  • the memory can also store information of the device type.
  • the processor 1710 can be configured to execute instructions stored in a memory, and when the processor 1710 executes instructions stored in the memory, the processor 1710 is configured to perform the various steps of the method embodiments corresponding to the terminal described above and/or Process.
  • FIG. 18 shows still another communication device 1800 provided by an embodiment of the present application.
  • the apparatus 1800 includes a processor 1810, a transceiver 1820, and a memory 1830.
  • the processor 1810, the transceiver 1820, and the memory 1830 communicate with each other through an internal connection path.
  • the memory 1830 is configured to store instructions, and the processor 1810 is configured to execute instructions stored by the memory 1830 to control the transceiver 1820 to send signals and / or receive signals.
  • the transceiver 1820 is configured to acquire handover indication information of a protocol data unit PDU session established in the first network, where each PDU session in the established PDU session has the same data network name DNN; the processor 1810 is configured to use The handover indication information of the established PDU session, determining a target PDU session in the established PDU session; the transceiver 1820 is configured to send, by using the mobility management entity device of the second network, the first control plane function network element The ID of the target PDU session.
  • the device 1800 may be specifically the terminal in the foregoing method embodiment, and may be used to perform various steps and/or processes corresponding to the terminal in the foregoing method embodiment.
  • the memory 1830 can include read only memory and random access memory and provides instructions and data to the processor. A portion of the memory may also include a non-volatile random access memory.
  • the memory can also store information of the device type.
  • the processor 1810 can be configured to execute instructions stored in a memory, and when the processor 1810 executes instructions stored in the memory, the processor 1810 is configured to perform the first type of access network with the first network.
  • FIG. 19 shows still another communication device 1900 provided by an embodiment of the present application.
  • the apparatus 1900 includes a processor 1910, a transceiver 1920, and a memory 1930.
  • the processor 1910, the transceiver 1920, and the memory 1930 communicate with each other through an internal connection path.
  • the memory 1930 is configured to store instructions, and the processor 1910 is configured to execute instructions stored by the memory 1930 to control the transceiver 1920 to send signals and / or receive signals.
  • the transceiver 1920 is configured to receive a session establishment request message sent by the terminal, where the session establishment request message is used to request to establish a first protocol data unit PDU session, and the transceiver 1920 is further configured to acquire a handover indication of the first PDU session. information.
  • the device 1900 may be specifically the first control plane function network element or the second control plane function network element in the foregoing method embodiment, and may be used to perform the first control plane function network element or the second in the foregoing method embodiment.
  • the control plane functions the corresponding steps and/or processes of the network element.
  • the memory 1930 can include read only memory and random access memory and provides instructions and data to the processor. A portion of the memory may also include a non-volatile random access memory.
  • the memory can also store information of the device type.
  • the processor 1910 can be configured to execute instructions stored in the memory, and when the processor 1910 executes the instructions stored in the memory, the processor 1910 is configured to perform the method implementation corresponding to the core network element of the first network. The various steps and/or processes of the examples.
  • the transceiver described above can include a transmitter and a receiver.
  • the transceiver may further include an antenna, and the number of antennas may be one or more.
  • the memory can be a separate device or integrated into the processor.
  • the above various devices or parts of the device can be integrated into the chip for implementation, such as integration into a baseband chip.
  • the transceiver in FIG. 17 to FIG. 19 may also be a communication interface, which is not limited herein.
  • the first control plane function network element or the second control plane function network element may be a physical physical device, or may be a virtual functional network element, which is not limited herein.
  • the names of request messages, response messages, and other various messages are employed for convenience of description. However, these messages are merely illustrative of the content to be carried or the functions to be carried.
  • the specific name of the message is not limited to the present application, for example, it may be a first message, a second message, a third message, or the like. These messages can be specific messages and can be some of the fields in the message. These messages can also represent various service operations.
  • the processor of the foregoing device may be a central processing unit (CPU), and the processor may also be another general-purpose processor, a digital signal processor (DSP). ), application specific integrated circuit (ASIC), field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, and the like.
  • the general purpose processor may be a microprocessor or the processor or any conventional processor or the like.
  • each step of the above method may be completed by an integrated logic circuit of hardware in a processor or an instruction in a form of software.
  • the steps of the method disclosed in the embodiments of the present application may be directly implemented as a hardware processor, or may be performed by a combination of hardware and software units in the processor.
  • the software unit can be located in a conventional storage medium such as random access memory, flash memory, read only memory, programmable read only memory or electrically erasable programmable memory, registers, and the like.
  • the storage medium is located in a memory, and the processor executes instructions in the memory, in combination with hardware to perform the steps of the above method. To avoid repetition, it will not be described in detail here.
  • the computer program product includes one or more computer instructions.
  • the computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable device.
  • the computer instructions can be stored in a computer readable storage medium or transferred from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions can be from a website site, computer, server or data center Transmission to another website site, computer, server, or data center by wire (eg, coaxial cable, fiber optic, digital subscriber line (DSL), or wireless (eg, infrared, wireless, microwave, etc.).
  • the readable storage medium can be any available media that can be accessed by a computer or a data storage device such as a server, data center, or the like that includes one or more available media.
  • the available media can be magnetic media (eg, a floppy disk, a hard disk, Magnetic tape), optical medium (for example, DVD), or semiconductor medium (such as solid state disk (SSD)).
  • the disclosed systems, devices, and methods may be implemented in other manners.
  • the device embodiments described above are merely illustrative.
  • the division of the unit is only a logical function division.
  • there may be another division manner for example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored or not executed.
  • the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, and may be in an electrical, mechanical or other form.
  • the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment.
  • each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.
  • the functions may be stored in a computer readable storage medium if implemented in the form of a software functional unit and sold or used as a standalone product.
  • the technical solution of the present application which is essential or contributes to the prior art, or a part of the technical solution, may be embodied in the form of a software product, which is stored in a storage medium, including
  • the instructions are used to cause a computer device (which may be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present application.
  • the foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, and the like, which can store program codes. .

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Abstract

本申请提供了一种通信方法和通信装置，有助于控制PDU会话的切换，从而提高系统性能。该方法包括：网络设备根据终端在第一网络建立的协议数据单元PDU会话的切换指示信息，在所述建立的PDU会话中确定目标PDU会话，其中所述建立的PDU会话中每个PDU会话具有相同的数据网络名称DNN；所述网络设备向第二网络的移动性管理实体设备发送所述目标PDU会话的会话信息。

Description

通信方法和通信装置
本申请要求于2018年1月15日提交中国国家知识产权局、申请号为201810037209.3、发明名称为“通信方法和通信装置”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及通信领域，并且更具体地，涉及通信领域中的通信方法和通信装置。
背景技术
随着无线通信技术的快速发展，第五代(Fifth Generation，5G)移动通信技术应运而生。在网络部署初期，由于5G网络覆盖不足，因此，当用户设备(User Equipment，UE)的位置发生变化时，UE需要在5G网络和第四代(Forth Generation，4G)网络之间的切换会话。
在4G网络中建立分组数据网络(packet data network，PDN)连接需要接入点名称(access point name，APN)参数，而在5G中创建协议数据单元(protocol data unit，PDU)会话时需要数据网络名称(data network name，DNN)。4G中APN与5G中的DNN是等价的。
UE在5G中可能建立有一个或多个PDU会话，且这些PDU会话可能使用相同的DNN。并且5G没有规定相同DNN的会话必须选择相同的会话管理设备，因此，这些具有相同DNN的一个或多个PDU会话可能锚定在不同的会话管理设备上。在4G中，为了进行APN聚合最大比特率(aggregated maximum bit rate，AMBR)的控制，要求一个相同APN的一个或多个PDN连接只能锚定在一个会话管理设备上。相同DNN的一个或多个PDU会话进行切换时，会导致无法控制的情形，从而使得系统性能较差。
发明内容
本申请提供一种通信方法和通信装置，有助于提高系统性能。
第一方面，提供了一种通信方法，包括：网络设备根据终端在第一网络建立的协议数据单元PDU会话的切换指示信息，在所述建立的PDU会话中确定目标PDU会话，其中所述建立的PDU会话中每个PDU会话具有相同的数据网络名称DNN；所述网络设备向第二网络的移动性管理实体设备发送所述目标PDU会话的会话信息。
因此，在本申请实施例中，网络设备可以根据建立的PDU会话的切换指示信息在建立的PDU会话中确定目标PDU会话，这样，该目标PDU会话就可以是作为能够切换到第二网络的PDU会话，可以避免终端在第一网络建立的PDU会话都要切换到第二网络的同一个控制面功能网元时而造成的无法控制的情形，有助于控制PDU会话的切换，从而提高系统性能。
可选地，终端在第一网络建立的PDU会话可以为一个或多个。可选地，若终端在第一网络建立的PDU会话为一个，则终端在第一网络建立的PDU会话的切换指示信息为一个；若终端在第一网络建立的PDU会话为多个，则终端在第一网络建立的PDU会话的切换指示信息可以是多个PDU会话的切换指示信息。
可选地，所述第一网络为5G网络，所述第二网络为4G网络。
可选地，所述网络设备为用户数据管理网元或者为接入和移动性管理功能实体。
在某些实现方式中，所述切换指示信息用于指示所述建立的PDU会话中每个PDU会话的切换优先级，其中，在所述建立的PDU会话中确定目标PDU会话，包括：所述网络设备将所述建立的PDU会话中切换优先级最高的PDU会话确定为所述目标PDU会话。例如，可以用数字表示PDU会话的切换优先级。可选地，切换优先级最高的PDU会话可以为一个或多个。
在某些实现方式中，所述切换指示信息用于指示所述建立的PDU会话中每个PDU会话是否能够切换；其中，在所述建立的PDU会话中确定目标PDU会话，包括：在所述切换指示信息指示的能够切换的PDU会话只有一个的情况下，则所述网络设备确定该能够切换的PDU会话为所述目标PDU会话；在所述切换指示信息指示能够切换的PDU会话至少有两个的情况下，则所述网络设备在该至少两个PDU会话中确定所述目标PDU会话。
在某些实现方式中，在所述切换指示信息指示的能够切换的PDU会话至少有两个的情况下，则所述网络设备在该至少两个PDU会话中确定所述目标PDU会话，包括：若所述至少两个PDU会话属于同一个控制面功能网元，则所述网络设备将该至少两个会话确定为所述目标会话；若所述至少两个PDU会话属于不同的控制面功能网元，则所述网络设备根据该至少两个PDU会话的该至少两个PDU会话中每个PDU会话的辅助信息，在该至少两个PDU会话中确定目标PDU会话。
在本申请实施例中，切换指示信息可以指示PDU会话能够切换，网络设备获取到切换指示信息指示的PDU会话可以有至少两个，则网络设备判断该至少两个PDU会话是不是属于同一个控制面功能网元，若属于同一个控制面功能网元，则将该至少两个PDU会话都可以进行切换，即都为目标PDU会话；若该至少两个PDU会话不属于同一个控制面功能网元，则网络设备可以根据该至少两个PDU会话的辅助信息确定目标PDU会话，或者网络设备可以根据该至少两个PDU会话的辅助信息确定该至少两个PDU会话的优先级，将切换优先级最高的PDU会话确定为目标PDU会话。
在某些实现方式中，在所述网络设备根据终端在第一网络中建立的协议数据单元PDU会话的切换指示信息，在所述建立的PDU会话中确定目标PDU会话之前，所述方法还包括：所述网络设备接收来自第一控制面功能网元发送的所述建立的PDU会话中第一PDU会话的辅助信息；所述网络设备根据所述辅助信息确定所述第一PDU会话的切换指示信息在这里，网络设备可以是用户数据管理网元，也可以是接入和移动性管理设备。
可选地，当所述网络设备是用户数据管理网元时，所述方法还包括：所述用户数据管理网元向所述第一控制面功能网元发送所述第一PDU会话的切换指示信息。
换句话说，用户数据管理网元可以根据接收到的第一控制面功能网元发送的第一PDU会话的辅助信息，根据第一PDU会话的辅助信息确定第一PDU会话的切换指示信息，并将确定的第一PDU会话的切换指示信息发送给第一控制面功能网元。
在某些实现方式中，所述辅助信息包括以下至少一项：PDU会话对应的互联网协议(internet protocol，IP)地址版本、PDU会话对应的单网络切片辅助信息、PDU会话对应的会话和服务连续性SSC模式、PDU会话对应的分配和保留切换优先级ARP、PDU会话对应的业务类型和PDU会话对应的建立时间。
在某些实现方式中，在所述网络设备根据终端在第一网络中建立的协议数据单元PDU会话的切换指示信息，在所述建立的PDU会话中确定目标PDU会话之前，所述方法包括：所述网络设备接收来自至少一个控制面功能网元发送的终端在第一网络建立的PDU会话的切换指示信息。
在某些实现方式中，所述网络设备为用户数据管理网元，在所述网络设备根据终端在第一网络中建立的协议数据单元PDU会话的切换指示信息，在所述建立的PDU会话中确定目标PDU会话之前，所述方法包括：所述用户数据管理网元接收来自第二控制面功能网元发送的终端在第一网络建立的PDU会话中的第二PDU会话的初始切换指示信息；所述用户数据管理网元调整所述初始切换指示信息得到所述第二PDU会话的切换指示信息；所述方法还包括：所述用户数据管理网元向所述第二控制面功能网元发送所述第二PDU会话的切换指示信息。
换句话说，用户数据管理网元可以将第二控制面功能网元发送的第二PDU会话的初始切换指示信息进行调整，可以将调整后的第二PDU会话的切换指示信息发送给第二控制面功能网元。具体调整方式根据是根据本地策略进行调整，本申请实施例对此不作限定。
在某些实现方式中，所述目标PDU会话的会话信息包括所述目标PDU会话对应的控制面功能网元的标识以及所述目标PDU会话的DNN。
第二方面，提供了一种通信方法，包括：终端获取在第一网络中建立的协议数据单元PDU会话的切换指示信息，所述建立的PDU会话中每个PDU会话具有相同的数据网络名称DNN；所述终端根据所述建立的PDU会话的切换指示信息，在所述建立的PDU会话中确定目标PDU会话；所述终端经由第二网络的移动性管理实体设备向第一控制面功能网元发送所述目标PDU会话的标识。
因此，在本申请实施例中，终端可以根据建立的PDU会话的切换指示信息在建立的PDU会话中确定目标PDU会话，这样，该目标PDU会话就可以是作为能够切换到第二网络的PDU会话，可以避免终端在第一网络建立的PDU会话都要切换到第二网络的同一个控制面功能网元时而造成的无法控制的情形，有助于控制PDU会话的切换，从而提高系统性能。
在某些实现方式中，所述切换指示信息用于指示所述建立的PDU会话中每个PDU会话的切换优先级，其中，在所述建立的PDU会话中确定目标PDU会话，包括：所述终端将所述建立的PDU会话中切换优先级最高的PDU会话确定为所述目标PDU会话。
在某些实现方式中，所述切换指示信息用于指示所述建立的PDU会话中每个PDU会话是否能够切换；其中，在所述建立的PDU会话中确定目标PDU会话，包括：所述终端将所述建立的PDU会话中能够切换的PDU会话确定为所述目标PDU会话。
在某些实现方式中，所述终端经由第二网络的移动性管理实体设备向第一控制面功能网元发送所述目标PDU会话的标识，包括：所述终端向所述移动性管理实体设备发送所述目标PDU会话的标识以及所述目标PDU会话的DNN，所述目标PDU会话的DNN用于所述移动性管理实体设备确定所述第一控制面功能网元，以便于所述移动性管理实体设备向所述第一控制面功能网元发送所述目标PDU会话的标识。
在某些实现方式中，所述终端向所述移动性管理实体设备发送所述目标PDU会话的标识以及所述目标PDU会话的数据网络名称，包括：所述终端向所述移动性管理实体设备发送第一请求消息，所述第一请求消息中携带所述目标PDU会话的标识以及所述目标PDU会话的DNN，所述第一请求消息为附着请求消息或者会话建立请求消息。
在某些实现方式中，所述终端获取在第一网络中建立的PDU会话的切换指示信息，包括：所述终端接收来自至少一个控制面功能网元发送的所述建立的PDU会话的切换指示信息。
在本申请实施例中，终端可以接收来自至少一个控制面功能网元发送的所述建立的PDU会话的切换指示信息，至少一个控制面功能网元发送的所述建立的PDU会话的切换指示信息可以是至少一个控制面功能网元自身确定的，或者是至少一个控制面功能网元接收用户数据 管理设备发送的，本申请实施例对此不作限制。
在某些实现方式中，所述终端获取在第一网络中建立的PDU会话的切换指示信息，包括：所述终端向第二控制面功能网元发送所述第一PDU会话的初始切换指示信息，所述初始切换指示信息用于确定所述第一PDU会话的切换指示信息；所述终端接收所述第二控制面功能网元发送的所述第一PDU会话的切换指示信息。
换句话说，终端可以向第二控制面功能网元发送第一PDU会话的初始切换指示信息，第二控制面功能网元可以对第一PDU会话的初始切换指示信息进行调整得到第一PDU会话的切换指示信息，或者第二控制面功能网元可以将第一PDU会话的初始切换指示信息发送给用户数据管理网元，用户数据管理网元对第一PDU会话的初始切换指示信息进行调整，将调整得到的第一PDU会话的切换指示信息发送给第二控制面功能网元，第二控制面功能网元向终端发送第一PDU会话的切换指示信息。
第三方面，提供了一种通信方法，包括：第一控制面功能网元接收终端发送的会话建立请求消息，所述会话建立请求消息用于请求建立第一协议数据单元PDU会话；所述第一控制面功能网元获取所述第一PDU会话的切换指示信息。第一控制面功能网元可以是多个控制面功能网元中的任何一个。多个控制面功能网元接收到的会话建立请求消息中可以是分别请求建立多个PDU会话，该多个PDU会话具有相同的DNN。
在某些实现方式中，所述切换指示信息用于指示所述第一PDU会话的优先级或者用于指示所述第一PDU会话是否能够切换。
在某些实现方式中，所述会话建立请求消息包括所述第一PDU会话的切换指示信息，其中，所述第一控制面功能网元获取所述第一PDU会话的切换指示信息，包括：所述第一控制面功能网元在所述会话建立请求消息中获取所述第一PDU会话的切换指示信息；所述方法还包括：所述第一控制面功能网元向用户数据管理网元或接入和移动性管理功能设备发送所述第一PDU会话的切换指示信息。
在本申请实施例中，终端向第一控制面功能网元发送的会话建立请求消息中携带第一PDU会话的切换指示信息，则第一控制面功能网元可以在会话建立请求消息中获取第一PDU会话的切换指示信息。
在某些实现方式中，所述第一控制面功能网元获取所述第一PDU会话的切换的切换指示信息，包括：所述第一控制面功能网元获取所述第一PDU会话的初始切换指示信息；所述第一控制面功能网元获取根据所述初始切换指示信息调整得到的所述第一PDU会话的切换指示信息；所述方法还包括：所述第一控制面功能网元向所述终端或者用户数据管理网元或者接入和移动性管理功能设备发送所述第一PDU会话的切换指示信息。
在本申请实施例中，第一PDU会话的初始切换指示信息可以被调整，调整为第一PDU会话的切换指示信息。具体可以包括以下几种方式，第一，第一控制面功能网元接收终端发送第一PDU会话的初始切换指示信息，会话建立请求消息中可以携带该初始切换指示信息，第一控制面功能网元可以对的第一PDU会话的初始切换指示信息进行调整，第一控制面功能网元将调整后的第一PDU会话的切换指示信息可以发送给终端，例如通过PCO发送终端，这样终端可以接收多个控制面功能网元发送的多个PDU会话的切换指示信息，终端可以根据多个PDU会话的切换指示信息确定目标PDU会话，即为需要切换的PDU会话。第一控制面功能网元可以将调整后的第一PDU会话的切换指示信息发送给用户数据管理网元，这样用户数据管理网元可以接收多个控制面功能网元发送的多个PDU会话的切换指示信息，用户数据管理网 元可以根据多个PDU会话的切换指示信息确定目标PDU会话，即为需要切换的PDU会话。第一控制面功能网元可以将调整后的第一PDU会话的切换指示信息发送给接入和移动性管理功能设备，这样接入和移动性管理功能设备可以接收多个控制面功能网元发送的多个PDU会话的切换指示信息，接入和移动性管理功能设备可以根据多个PDU会话的切换指示信息确定目标PDU会话，即为需要切换的PDU会话。第二，第一控制面功能网元可以接收终端发送第一PDU会话的初始切换指示信息或者自身确定第一PDU会话的初始切换指示信息，然后将第一PDU会话的初始切换指示信息发送给用户数据管理功能网元，用户管理功能网元可以对第一PDU会话的初始切换指示信息进行调制得到第一PDU会话的切换指示信息，用户管理功能网元将调整后的第一PDU会话的切换指示信息发送给第一控制面功能网元，第一控制面功能网元可以将调整后的第一PDU会话的切换指示信息发送给接入和移动性管理功能设备，这样接入和移动性管理功能设备可以接收多个控制面功能网元发送的多个PDU会话的切换指示信息，接入和移动性管理功能设备可以根据多个PDU会话的切换指示信息确定目标PDU会话，即为需要切换的PDU会话。第一控制面功能网元可以将调整后的第一PDU会话的切换指示信息发送给终端，这样终端可以接收多个控制面功能网元发送的多个PDU会话的切换指示信息，终端可以根据多个PDU会话的切换指示信息确定目标PDU会话，即为需要切换的PDU会话。
在某些实现方式中，所述第一控制面功能网元获取所述第一PDU会话的切换的切换指示信息，包括：所述第一控制面功能网元向用户数据管理网元发送所述第一PDU会话的辅助信息；所述第一控制面功能网元接收所述用户数据管理网元发送的所述第一PDU会话的切换指示信息，所述第一PDU会话的切换指示信息根据所述第一PDU会话的辅助信息确定，所述第一PDU会话的辅助信息包括所述第一PDU会话对应的互联网协议IP地址版本、所述第一PDU会话对应的单网络切片辅助信息、所述第一PDU会话对应的会话和服务连续性SSC模式、所述第一PDU会话对应的分配和保留切换优先级ARP、所述第一PDU会话的对应的业务类型和所述第一PDU会话对应的建立时间中的至少一项；所述方法还包括：所述第一控制面功能网元向所述终端或接入和移动性管理功能设备发送所述第一PDU会话的切换指示信息。
在某些实现方式中，所述方法还包括：第一控制面功能网元接收第二网络的移动性管理设备发送的所述目标PDU会话的标识和所述目标PDU会话的DNN，所述第一控制面功能网元根据所述目标PDU会话的标识和所述目标PDU会话的DNN在自身保存的所述DNN对应的多个PDU会话中查找目标PDU会话，若查找到所述目标PDU会话，则将该目标PDU会话进行切换，若没有查找到该目标PDU会话，则拒绝该目标PDU会话。
在某些实现方式中，所述方法还包括：第一控制面功能网元接收第二网络的移动性管理实体设备发送的第一数据网络名称(该第一数据网络名称为终端向第二网络的移动性管理实体设备发送的当前PDU会话的数据网络名称)对应PDU会话更新请求，第一控制面功能网元在接收到第一数据网络名称对应的会话更新请求后，第一控制面功能网元根据第一数据网络名称获取该第一数据网络名称对应的PDU会话，若对应的PDU会话为一个，则该PDU会话即为需要切换的会话。若对应的PDU会话为多个，该第一控制面功能网元选择一个PDU会话作为需要切换的PDU会话。该第一控制面功能网元可以任选一个PDU会话作为需要切换的PDU会话，或者PDU会话的辅助信息确定切换的PDU会话。第一控制面功能网元将切换的PDU会话的标识向终端发送。
在某些实现方式中，所述方法还包括：所述第一控制面功能网元向用户数据管理网元发送所述第一PDU会话的数据网络名称DNN以及所述第一控制面功能网元的标识。可选地，第 一控制面功能网元可以向用户数据管理网元发送第一PDU会话的会话信息，会话信息包括第一PDU会话的切换指示信息、第一PDU会话的DNN以及第一控制面控制网元的标识，即可以将第一PDU会话的切换指示信息、第一PDU会话的DNN以及第一控制面控制网元的标识同时发送给用户数据管理网元。这样，用户数据管理网元就可以保存第一PDU会话的会话信息，当用户数据管理网元接收到多个PDU会话(具有相同的DNN)的会话信息时，根据多个PDU会话的切换指示信息确定目标PDU会话，然后将目标PDU会话的DNN以及该目标PDU会话对应的控制面功能网元的标识发送给第二网络的移动性管理功能实体设备。
第四方面，提供了一种通信方法，包括：终端向第二网络的移动性管理实体设备发送当前PDU会话对应的第一数据网络名称；终端接收控制面功能网元发送的已经切换的PDU会话的标识，根据PDU会话的标识确定已经切换了的PDU会话。可选地，终端接收控制面功能网元发送的PCO，在PCO中获取已经切换了的PDU会话的标识，根据PDU会话的标识确定已经切换了的PDU会话，这样UE可以将PDN连接与相应的会话关联起来。
在某些实现方式中，可选地，终端向第二网络的移动性管理实体设备发送当前PDU会话对应的第一数据网络名称，包括：终端向第二网络的移动性管理实体设备发送附着请求消息或者会话建立请求消息，附着请求消息或会话建立请求消息中携带当前PDU会话对应的数据网络名称。
在某些实现方式中，可选地，若终端在附着请求消息中向第二网络的移动性管理实体设备发送当前PDU会话对应的数据网络名称，则控制面功能网元在确定需要切换的PDU会话之后，在附着流程中切换PDU会话，若终端在会话建立请求消息中携带当前PDU会话对应的数据网络名称，则控制面功能网元在确定需要切换的PDU会话之后，在会话建立请求的流程中切换PDU会话。切换完成之后，控制面功能网元将已经切换的PDU会话的标识向终端发送。例如控制面功能网元向终端发送PCO，PCO中携带已经切换的PDU会话的标识。
第五方面，提供了一种通信装置，用于执行上述第一方面或第一方面的任一可能的实现方式中的方法。具体地，该装置包括用于执行上述第一方面或第一方面的任一可能的实现方式中的方法的单元。
第六方面，提供了一种通信装置，用于执行上述第二方面或第二方面的任一可能的实现方式中的方法。具体地，该装置包括用于执行上述第二方面或第二方面的任一可能的实现方式中的方法的单元。
第七方面，提供了一种通信装置，用于执行上述第三方面或第三方面的任一可能的实现方式中的方法。具体地，该装置包括用于执行上述第三方面或第三方面的任一可能的实现方式中的方法的单元。
第八方面，提供了一种通信装置，用于执行上述第四方面或第四方面的任一可能的实现方式中的方法。具体地，该装置包括用于执行上述第四方面或第四方面的任一可能的实现方式中的方法的单元。
第九方面，提供了一种通信装置，该装置包括：收发器(可以包括发送器和接收器)、存储器和处理器。其中，该收发器、该存储器和该处理器通过内部连接通路互相通信，该存储器用于存储指令，该处理器用于执行该存储器存储的指令，以控制接收器接收信号，并控制发送器发送信号，使得该装置执行第一方面或第一方面的任一种可能的实现方式中的方法。
第十方面，提供了一种通信装置，该装置包括：收发器(可以包括发送器和接收器)、存储器和处理器。其中，该收发器、该存储器和该处理器通过内部连接通路互相通信，该存储 器用于存储指令，该处理器用于执行该存储器存储的指令，以控制接收器接收信号，并控制发送器发送信号，使得该装置执行第二方面或第二方面的任一种可能的实现方式中的方法。
第十一方面，提供了一种通信装置，该装置包括：收发器(可以包括发送器和接收器)、存储器和处理器。其中，该收发器、该存储器和该处理器通过内部连接通路互相通信，该存储器用于存储指令，该处理器用于执行该存储器存储的指令，以控制接收器接收信号，并控制发送器发送信号，使得该装置执行第三方面或第三方面的任一种可能的实现方式中的方法。
第十二方面，提供了一种通信的装置，该装置包括：收发器(可以包括发送器和接收器)、存储器和处理器。其中，该收发器、该存储器和该处理器通过内部连接通路互相通信，该存储器用于存储指令，该处理器用于执行该存储器存储的指令，以控制接收器接收信号，并控制发送器发送信号，使得该装置执行第四方面或第四方面的任一种可能的实现方式中的方法。
第十三方面，提供了一种处理业务的系统，包括第五方面或其任一种可选实现方式中的装置、第六方面或其任一种可选实现方式中的装置以及第七方面或其任一种可选实现方式中的装置。可选地，所述系统包括第五方面或其任一种可选实现方式中的装置、第六方面或其任一种可选实现方式中的装置以及第八方面或其任一种可选实现方式中的装置。可选地，所述系统包括第九方面或其任一种可选实现方式中的装置、第十方面或其任一种可选实现方式中的装置和第十一方面或其任一种可选实现方式中的装置。可选地，所述系统包括第九方面或其任一种可选实现方式中的装置、第十方面或其任一种可选实现方式中的装置和第十二方面或其任一种可选实现方式中的装置。
第十四方面，提供一种计算机可读存储介质，所述计算机可读存储介质中存储有指令，当其在计算机上运行时，使得计算机执行如第一方面或第一方面的任一可能的实现方式中的方法。
第十五方面，提供一种计算机可读存储介质，所述计算机可读存储介质中存储有指令，当其在计算机上运行时，使得计算机执行如第二方面或第二方面的任一可能的实现方式中的方法。
第十六方面，提供一种计算机可读存储介质，所述计算机可读存储介质中存储有指令，当其在计算机上运行时，使得计算机执行如第三方面或第三方面的任一可能的实现方式中的方法。
第十七方面，提供一种计算机可读存储介质，所述计算机可读存储介质中存储有指令，当其在计算机上运行时，使得计算机执行如第四方面或第四方面的任一可能的实现方式中的方法。
第十八方面，本申请提供了一种包含指令的计算机程序产品，当其在计算机上运行时，使得计算机执行上述第一方面或第一方面的任一可能的实现方式中的方法。
第十九方面，本申请提供了一种包含指令的计算机程序产品，当其在计算机上运行时，使得计算机执行上述第二方面或第二方面的任一可能的实现方式中的方法。
第二十方面，本申请提供了一种包含指令的计算机程序产品，当其在计算机上运行时，使得计算机执行上述第三方面或第三方面的任一可能的实现方式中的方法。
第二十一方面，本申请提供了一种包含指令的计算机程序产品，当其在计算机上运行时，使得计算机执行上述第四方面或第四方面的任一可能的实现方式中的方法。
第二十二方面，本申请提供了一种通信芯片，其中存储有指令，当其在终端或网络设备或控制面功能网元上运行时，使得终端或网络设备或控制面功能网元执行上述各方面所述的 任一方法。
附图说明
图1是本申请实施例提供的4G网络和5G网络互通架构系统的示意图。
图2是本申请实施例提供的通信方法示意图。
图3是本申请实施例提供的另一通信方法示意图。
图4是本申请实施例提供的另一通信方法示意图。
图5是本申请实施例提供的又一通信方法示意图。
图6是本申请实施例提供的又一通信方法示意图。
图7是本申请实施例提供的又一通信方法示意图。
图8是本申请实施例提供的又一通信方法示意图。
图9是本申请实施例提供的又一通信方法示意图。
图10是本申请实施例提供的又一通信方法示意图。
图11是本申请实施例提供的又一通信方法示意图。
图12是本申请实施例提供的又一通信方法示意图。
图13是本申请实施例提供的又一通信方法示意图。
图14是本申请实施例提供的通信装置示意性框图。
图15是本申请实施例提供的另一通信装置示意性框图。
图16是本申请实施例提供的又一通信装置示意性框图。
图17是本申请实施例提供的又一通信装置示意性框图。
图18是本申请实施例提供的又一通信装置示意性框图。
图19是本申请实施例提供的又一通信装置示意性框图。
具体实施方式
为了方便理解本申请实施例的技术方案，首先给出本申请相关技术的简要介绍如下。
本发明的实施例提供一种移动性管理的方法，可应用于如图1所示的4G网络和5G网络互通架构系统100中，如图1所示，包括4G网络与5G网络共用用户面功能(user plane function，UPF)实体+PDN网关用户面功能(PDN gateway user plane function，PGW-U)实体、会话管理功能(session management function，SMF)实体+PDN网关控制面功能(PDN gateway control plane function，PGW-C)实体、策略控制功能(policy control function，PCF)实体+策略和计费规则功能(policy and charging rules function，PCRF)实体、归属签约用户服务器(home subscriber server，HSS)+统一数据管理(unified data management，UDM)实体。这里“+”表示合设，UPF为5G网络的用户面功能，PGW-U是与UPF对应的4G网络的网关用户面功能，SMF是5G网络的会话管理功能，PGW-C是与SMF对应的4G网络中的网关控制面功能，PCF是5G网络的策略控制功能、PCRF是与PCF对应的4G网络的策略计费规则功能。这里的“合设”是指同一个设备同时具备两个实体的功能。本申请实施例中，为方便表述，将HSS+UDM实体称之为用户数据管理网元，将PGW-C实体+SMF实体称之为控制面功能网元，将UPF实体+PGW-U实体称之为用户面功能网元，在此进行统一说明，以下不再赘述。当然，上述合设后的网络设备也可以用其他名称，本申请实施例对此不作具体限定。
此外，如图1所示，上述4G网络和5G网络互通架构中还可以包括移动性管理实体 (Mobility Management Entity，MME)和服务网关(Serving Gateway，SGW)，以及5G网络中的接入和移动性管理功能(Access and Mobility Management Function，AMF)实体。其中，终端通过演进型通用陆地无线接入网(evolved universal terrestrial radio access network，E-UTRAN)设备接入4G网络，终端通过下一代无线接入网(next generation radio access network，NG-RAN)设备接入5G网络。E-UTRAN设备通过S1-MME接口与MME通信，E-UTRAN设备通过S1-U接口与SGW通信，MME通过S11接口与SGW通信，MME通过S6a接口与用户数据管理实体通信，MME通过N26接口与AMF实体通信，SGW通过S5-U接口与PGW-U实体+UPF实体通信，SGW通过S5-C接口与PGW-C实体+SMF实体通信，PGW-U实体+UPF实体通过N3接口与NG-RAN设备通信，PGW-U实体+UPF实体通过N4接口与PGW-C实体+SMF实体通信，PGW-C实体+SMF实体通过N7接口与PCRF实体+PCF实体通信，HSS+UDM实体通过N10接口与PGW-C实体+SMF实体通信，HSS+UDM实体通过N8接口与AMF实体通信，PCRF实体+PCF实体通过N15接口与AMF实体通信，PGW-C实体+SMF实体通过N11接口与AMF实体通信，AMF实体通过N2接口与NG-RAN设备通信，AMF实体通过N1接口与终端通信。在上述互通架构中MME与AMF间的N26接口在某些场景下可能并不存在，该N26接口可用于终端上下文传递以及切换过程。本申请将会针对MME与AMF间是否有N26接口，分别描述相关可能的实现。
需要说明的是，图1中仅以终端为UE为例，图1中的各个网元之间的接口名字只是一个示例，具体实现中接口名字可能为其他名字，本申请实施例对此不作具体限定。
需要说明的是，5G网络中的NG-RAN设备也可以称之为接入设备，该接入设备指的是接入核心网的设备，例如可以是基站，宽带网络业务网关(broadband network gateway，BNG)，汇聚交换机，非3GPP接入设备等。基站可以包括各种形式的基站，例如：宏基站，微基站(也称为小站)，中继站，接入点等，本申请实施例对此不作具体限定。
当然，4G网络和5G网络中还可以有其它的网元，比如，4G网络中还可以包括通用分组无线系统(general packet radio system，GPRS)业务支撑节点(serving GPRS support node，SGSN)等，5G网络中还可以包括鉴权服务功能(authentication server function，AUSF)实体和网络切片选择功能(network slice selection function，NSSF)实体等，本申请实施例对此不作具体限定。
本申请实施例中所涉及到的终端(terminal)可以包括各种具有无线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它处理设备；还可以包括用户单元(subscriber unit)、蜂窝电话(cellular phone)、智能电话(smart phone)、无线数据卡、个人数字助理(personal digital assistant，PDA)电脑、平板型电脑、无线调制解调器(modem)、手持设备(handheld)、膝上型电脑(laptop computer)、无绳电话(cordless phone)或者无线本地环路(wireless local loop，WLL)台、机器类型通信(machine type communication,MTC)终端、用户设备(user equipment，UE)，移动台(mobile station，MS)，终端设备(terminal device)等。为方便描述，本申请中，上面提到的设备统称为终端。
APN：
在4G网络中，终端在发起分组业务时可向MME提供APN。MME根据终端所提供的APN，通过域名服务器(domain name server，DNS)进行域名解析，从而获取到会话管理网元的地址(例如，网际协议地址)，从而将终端接入到APN对应的PDN中。
DNN：
在5G网络中，终端在发起PDU会话建立时可以向AMF提供S-NSSAI以及DNN。AMF基于S-NSSAI、DNN以及其他信息(例如终端的签约信息以及本地运营商策略等)确定会话管理网元的地址。被确定的会话管理网元基于S-NSSAI和DNN为终端建立一个PDU会话。
4G网络中的APN相当于5G网络中的DNN，4G网络中的PDN连接相当于5G网络中的PDU会话，UE在5G中可能建立有一个或多个PDU会话，且这些PDU会话可能使用相同的DNN，这些具有相同DNN的一个或多个PDU会话可能锚定在不同的控制面功能网元上。在4G中，为了进行APN聚合最大比特率(aggregated maximum bit rate，AMBR)的控制，要求一个相同APN的一个或多个PDN连接只能锚定在一个控制面功能网元上。如果将5G中具有相同DNN的一个或多个PDU会话切换为4G中的具有相同APN的一个或多个PDN连接时，则如何进行切换会话是亟待解决的问题。针对该问题，本申请实施例中可以根据切换指示信息在具有相同DNN的至少一个PDU会话中确定目标PDU会话，该目标PDU会话作为可以切换的PDU会话，从而能够避免不知如何将具有相同DNN的至少一个PDU会话进行切换而导致了无法控制的情形，能够提高系统性能。下面结合附图详细描述本申请实施例提供的通信方法。
图2示出了本申请实施例提供的通信方法200，该方法200包括：
S210，网络设备根据终端在第一网络建立的协议数据单元PDU会话的切换指示信息，在所述建立的PDU会话中确定目标PDU会话，其中所述建立的PDU会话中每个PDU会话具有相同的数据网络名称DNN。可选地，终端在第一网络建立的PDU会话可以为一个或多个。可选地，该目标PDU会话可以是一个或多个。可选地，网络设备可以是用户数据管理网元或者是接入和移动性管理功能设备。
需要说明的是，若终端在第一网络建立的N个PDU会话，则该N个PDU会话中M个PDU会话具有相同的数据网络名称，N大于或等于M，M和N为正整数。
应理解，所述建立的PDU会话的切换指示信息可以包括：所述建立的PDU会话中每个PDU会话可以存在对应的切换指示信息，并且建立的个PDU会话中可以存在切换指示信息相同或不同的PDU会话。或者所述建立的PDU会话的中至少存在一个PDU会话有对应的切换指示信息，例如，切换指示信息可以指示PDU会话能否被切换，例如，三个PDU会话中只有一个PDU会话能切换，则该PDU会话的存在切换指示信息，该切换指示信息指示该PDU会话能切换，剩下的两个PDU会话的是否能被切换可以不用指示，默认不能切换。
在本申请实施例中，切换指示信息至少存在两种不同指示作用，下面分两种情况来描述。
第一种情况，所述切换指示信息用于指示所述建立的DU会话中每个PDU会话的切换优先级，S220，包括：所述网络设备将所述建立的PDU会话中切换优先级最高的PDU会话确定为所述目标PDU会话。应理解，在本申请实施例中，每个PDU会话的切换优先级可以是表示优先级高低的数字，例如，优先级为1表示最高优先级，即优先切换到第二网络；优先级为100表示最低优先级，如当前有5个PDU会话，分别是会话1、会话2、会话3、会话4、会话5，优先级从高到低分别为1、2、3、4、5，则网络设备将会话1确定为目标会话。
第二种情况，所述切换指示信息用于指示所述建立PDU会话中每个PDU会话是否能够切换，例如，切换指示信息可以是指示域，如，某一个PDU会话的指时域为1表示该PDU会话可以切换，某一个PDU会话的指示域为0表示该PDU会话不可以切换，S220，包括：在所述切换指示信息指示的能够切换的PDU会话只有一个的情况下，则所述网络设备确定该能够切换的PDU会话为所述目标PDU会话，即仅存在一个PDU会话能切换，则该PDU会话即为目标PDU会话；在所述切换指示信息指示能够切换的PDU会话至少有两个的情况下，则所述网络 设备在该至少两个PDU会话中确定所述目标PDU会话，例如，网络设备可以在至少两个PDU会话中任意选择一个PDU会话作为目标PDU会话或者根据辅助信息选择一个PDU会话作为目标PDU会话。
可选地，在第二种情况下，在所述切换指示信息指示能够切换的PDU会话至少有两个的情况下，则所述网络设备在该至少两个PDU会话中确定所述目标PDU会话，包括：若所述至少两个PDU会话属于同一个控制面功能网元，则所述网络设备将该至少两个会话确定为所述目标会话，即网络设备可以将属于同一控制面功能网元的至少两个PDU会话都作为目标PDU会话切换至第二网络；若所述至少两个PDU会话属于不同的控制面功能网元，则所述网络设备根据所述至少两个PDU会话中每个PDU会话的辅助信息，在该至少两个PDU会话中确定目标PDU会话。可选地，网络设备可以根据每个PDU会话的辅助信息确定该至少两个PDU会话的切换优先级；所述网络设备根据该至少两个PDU会话的切换优先级，在该至少两个PDU会话中确定目标PDU会话。
可选地，辅助信息包括以下至少一项：所述PDU会话对应的互联网协议IP地址版本、PDU会话对应的单网络切片辅助信息(single network slice selection assistance information，S-NSSAI)、PDU会话对应的会话和服务连续性(session and service continuity，SSC)模式、PDU会话对应的分配和保留切换优先级(allocation and retention priority，ARP)、PDU会话的对应的业务类型和PDU会话对应的建立时间。举例来说，切换指示信息指示PDU会话1和PDU会话2能够切换，例如，PDU会话1属于语音业务，PDU会话2属于网络数据业务，则网络设备可以将PDU会话1确定为目标PDU会话，或者网络设备可以确定PDU会话1的优先级高于PDU会话2的优先级，将会话1确定为目标PDU会话，在没有其他更高优先级的PDU会话存在的情况下。又例如，PDU会话1的SSC模式为模式3，PDU会话2的SSC模式为模式2，则网络设备可以将PDU会话1确定为目标PDU会话，或者网络设备确定PDU会话1的优先级高于PDU会话2的优先级，在没有其他更高优先级的PDU会话存在的情况下，网络设备可以将PDU会话1确定为目标PDU会话。再例如，PDU会话1所属的S-NSSAI在配置时具有较高的优先级，PDU会话2所属的S-NSSAI在配置时具有较低的优先级，则网络设备可以将PDU会话1确定为目标PDU会话，或者网络设备可以确定PDU会话1的优先级高于PDU会话2的优先级，在没有其他更高优先级的PDU会话存在的情况下，网络设备可以将PDU会话1确定为目标PDU会话。又例如，当PDU会话对应的SSC模式是SSC模式3时，网络设备根据会话建立的时间，将后建立的PDU会话确定为目标PDU会话，或者网络设备将后建立的PDU会话的优先级设置的高于先建立的PDU会话，将优先级高的后建立的PDU会话确定为目标PDU会话。又例如，网络设备可根据本地配置的策略以及PDU会话对应的IP地址版本确定目标PDU会话，例如将IP地址版本为v6的PDU会话确定为目标PDU会话，或者网络设备可根据本地配置的策略以及PDU会话对应的IP地址版本设置PDU会话的优先级，比如，本地策略配置为优先切换IP版本为v6的PDU会话。又例如，网络设备可根据PDU会话的业务类型确定PDU会话的优先级，将业务类型为语音的PDU会话确定为目标PDU会话，或者将业务类型为语音的PDU会话设置更高的优先级等。
应理解，上述两种情况仅是示例性的说明，在实际应用中，切换指示信息还可以是其他的指示作用，本申请实施例对此不作限定。
作为一个可选实施例，在S210之前，方法还包括，网络设备获取终端在第一网络中的建立的PDU会话的切换指示信息，所述建立的PDU会话中每个PDU会话具有相同的数据网络名 称。
网络设备获取终端在第一网络中建立的PDU会话的切换指示信息可以通过以下几种方式获取：
第一种方式，所述网络设备接收来自至少一个控制面功能网元发送的终端在第一网络建立的PDU会话的切换指示信息。即至少一个控制面功能网元每个控制面功能网元都能获取到每个控制面功能网关对应的PDU会话的切换指示信息，例如，每个控制面功能网关可以获取终端发送的对应的PDU会话的切换指示信息，每个控制面功能网元可以将自身确定的对应的PDU会话的切换指示信息发送给网络设备，或者，每个控制面功能网元可以将终端发送的对应PDU会话的切换指示信息进行调整得到调整后的PDU会话的切换指示信息，然后发送给网络设备，例如，网络设备可以是接入和移动性管理功能设备或者用户数据管理网元，这样，接入和移动性管理功能设备就可以根据建立的PDU会话的切换指示信息在建立的PDU会话中确定目标PDU会话，或者用户数据管理网元就可以根据建立的PDU会话的切换指示信息在建立的PDU会话中确定目标PDU会话。
第二种方式，所述网络设备为用户数据管理网元，例如，可以是前述的HSS+UDM，或者可以是接入和移动性管理功能设备。所述网络设备接收来自第一控制面功能网元发送的所述建立的PDU会话中第一PDU会话的辅助信息，所述网络设备根据所述辅助信息确定所述第一PDU会话的切换指示信息，所述辅助信息可以是前述的辅助信息。这里以切换指示信息指示的是PDU会话的切换优先级进行举例说明，例如，网络设备可以将S-NSSAI优先级高的对应的PDU会话的优先级确定的高一些，将S-NSSAI优先级低的对应的PDU会话的优先级确定的低一些。又例如，当PDU会话对应的SSC模式是SSC模式3时，网络设备根据会话建立的时间，将后建立的PDU会话的优先级设置得高于先建立的PDU会话。又例如，网络设备可根据本地配置的策略以及PDU会话对应的IP地址版本设置会话的优先级，比如，本地策略配置为优先切换IP版本为v6的PDU会话。又例如，网络设备可根据第一PDU会话的业务类型确定PDU会话的优先级，将业务类型为语音的PDU会话设置更高的优先级等。
在第二种方式下，所述方法还包括：当所述用户数据管理网元时，所述用户数据管理网元向所述第一控制面功能网元发送所述第一PDU会话的切换指示信息。可选地，所述第一控制面功能网元可以将第一PDU会话的切换指示信息发送给终端。
第三种方式，所述网络设备为用户数据管理网元，例如，可以是前述的HSS+UDM。所述用户数据管理网元接收来自第二控制面功能网元发送的所述建立的PDU会话中的第二PDU会话的初始切换指示信息；所述用户数据管理网元调整所述初始切换指示信息得到所述第二PDU会话的切换指示信息；即用户数据管理网元可以对第二控制面功能网元发送过来的第二PDU会话的初始切换指示信息进行调整，例如，数据管理网元中已经保存了控制面功能网元1发送的PDU会话1的切换指示信息，当数据管理网元接收到控制面功能网元2(第二控制面功能网元)发送的PDU会话2(第二PDU会话)的切换指示信息(初始切换指示信息)时，发现PDU会话1和PDU会话2的切换指示信息相同，并且PDU会话1和PDU会话2具有相同的数据网络名称，当PDU会话1和PDU会话2所述的用户面功能网元不同，则数据管理网元可以对PDU会话2的切换指示信息进行调整，调整为不同于PDU会话1的切换指示信息，例如，根据PDU会话1和PDU会话2的签约数据、PDU会话1和PDU会话2对应的控制面功能网元的标识和本地策略中的至少一项进行调整PDU会话2的切换指示信息，本地策略可以是用户数据管理网元预设的策略，或者是根据历史数据得到的策略，又例如，网络设备根据前述的 辅助信息调整PDU会话2的切换指示信息，本申请实施例对此不作限制。
在第三种方式下，所述方法还包括：所述用户数据管理网元向所述第二控制面功能网元发送所述第二PDU会话的切换指示信息。即用户数据管理网元将调整得到的第二PDU会话的切换指示信息发送给第二控制面功能网元，可选地，该第二控制面功能网元可以将该第二PDU会话的切换指示信息发送给终端，可选地，该第二控制面功能网元可以将该第二PDU会话的切换指示信息发送给接入和移动性管理功能设备。
第四种方式，所述网络设备为用户数据管理网元，例如，可以是前述的HSS+UDM，则用户数据管理网元可以确定建立的PDU会话的每个PDU会话的切换指示信息。即用户数据管理网元可以根据每个PDU会话的签约数据以及本地策略确定每个PDU会话的切换指示信息。例如，本地策略可以是前述的根据辅助信息来确定每个PDU会话的切换指示信息。
应理解，网络设备获取建立PDU会话的切换指示信息中每个PDU会话的切换指示信息的获取方式可以是上述四种方式中的一种，可选地，每个PDU的切换指示信息的获取方式相同，或者，若建立的PDU会话为多个PDU会话，则该多个PDU会话中至少存在两个PDU会话的切换指示信息的获取方式可以不同，例如，采用上述四种方式中的两种。
S220，所述网络设备向第二网络的移动性管理实体设备发送所述目标PDU会话的会话信息，以便于第二网络的移动性管理实体设备根据所述目标PDU会话的会话信息确定该目标PDU会话的会话信息。
可选地，所述目标PDU会话的会话信息包括所述目标PDU会话对应的控制面功能网元的标识以及所述目标PDU会话的数据网络名称，这样，第二网络的移动性管理实体设备就可以根据目标PDU会话的对应的控制面功能网元的标识确定所述目标PDU会话对应的控制面功能网元，第二网络的移动性管理实体设备透传终端发送的目标PDU会话的标识给目标PDU会话对应的控制面功能网元，该目标PDU会话对应的控制面功能网元根据该目标PDU会话的标识查找该目标PDU会话，若查找到，则执行该目标PDU会话的切换。
可选地，第一网络可以是5G网络，第二网络可以是4G网络。
可选地，网络设备可以是接入和移动性管理功能实体，例如，可以是前述图1中的AMF；可选地，网络设备可以是用户数据管理网元，例如，可以是前述图1中的HSS+UDM。本申请实施例对网络设备具体是什么设备不作限定。
可选地，在本申请实施例中，目标PDU会话作为切换到第二网络的PDU会话，终端在第一网络建立的PDU会话中除了目标PDU会话之外的其他PDU会话可以进行释放。
因此，本申请实施例提供的通信方法，网络设备可以根据切换指示信息在终端在第一网络建立的PDU会话中确定目标PDU会话，这样该目标PDU会话就可以是作为能够切换到第二网络的PDU会话，可以避免终端在第一网络建立的PDU会话都要切换到第二网络的同一个控制面功能网元时而造成的无法控制的情形，有助于控制PDU会话的切换，从而提高系统性能。
图3示出了本申请实施例提供的通信方法300，该方法300包括：
S310，终端获取在第一网络中建立的协议数据单元PDU会话的切换指示信息，所述建立PDU会话中每个PDU会话具有相同的数据网络名称DNN。可选地，在第一网络建立的PDU会话可以为一个或多个。
应理解，所述建立的PDU会话的切换指示信息可以包括：所述建立的PDU会话中每个PDU会话可以存在对应的切换指示信息，并且建立的个PDU会话中可以存在切换指示信息相同或不同的PDU会话。或者所述建立的PDU会话的中至少存在一个PDU会话有对应的切换指示信 息，例如，切换指示信息可以指示PDU会话能否被切换，例如，三个PDU会话中只有一个PDU会话能切换，则该PDU会话的存在切换指示信息，该切换指示信息指示该PDU会话能切换，剩下的两个PDU会话的是否能被切换可以不用指示，默认不能切换。
终端获取在第一网络中建立的PDU会话的切换指示信息，可以有以下三种方式：
第一种方式，终端确定所述建立的PDU会话的切换指示信息。例如，终端根据本地策略确定至少一个PDU会话的切换指示信息，本地策略中可以是根据具有相同DNN的PDU会话的S-NSSAI确定建立的PDU会话的切换指示信息，例如，某个S-NSSAI在配置的过程中优先级较高，则该S-NSSAI对应PDU会话的优先级就最高，或者也可以根据PDU会话承载的业务类型确定PDU会话的切换指示信息，或者是根据二者的结合确定PDU会话的切换指示信息。以切换指示信息指示的是切换优先级为例，当终端根据S-NSSAI确定在第一网络建立的PDU会话的切换优先级时，如表1，终端可配置S-NSSAI与切换优先级之间的对应关系，如表2，终端可以配置业务类型与切换优先级之间的对应关系。
表1
S-NSSAI1 优先级＝1
S-NSSAI2 优先级＝2
S-NSSAI3 优先级＝3
S-NSSAI4 优先级＝4
表2
Figure PCTCN2019071718-appb-000001
应理解，当切换指示信息指示的是切换优先级时，终端在确定后建立的PDU会话的切换指示信息时可以不改变之前建立的PDU会话的切换指示信息。比如，终端按确定的规则确定PDU会话的切换指示信息。
当切换指示信息是指示PDU会话能否切换时，终端确定PDU会话是否可切换。终端可根据PDU会话对应的S-NSSAI确定PDU会话可切换，此时，终端在确定后建立的PDU会话的切换指示信息时会改变之前建立的PDU会话的切换指示信息。如表1中，终端先在S-NSSAI4对应的网络切片中建立了一个PDU会话，这个PDU会话是该DNN对应的第一个PDU会话，终端确定该PDU会话可切换。之后，终端在S-NSSAI1对应的网络切片中建立了一个新的PDU会话，由于S-NSSAI1的优先级高于S-NSSAI4，此时，终端将S-NSSAI1中的PDU会话设置为可切换，将S-NSSAI4中之前建立的PDU会话设置为不可切换。比如，终端在建立了一个新的SSC模式2的PDU会话时，将新PDU会话设置为可切换，将之前建立的相同DNN的SSC模式2的PDU会话设置为不可切换等。可选地，终端每确定一个PDU会话的切换指示信息都可以将该PDU会话的切换指示信息发送给对应的控制面功能网元。
应理解，当新建立的PDU会话的切换指示信息影响已建立的PDU会话的切换指示信息时，例如，新建立的PDU会话被终端确定为可切换从而导致之前建立的相同DNN的PDU会话被确定为不可切换，此时，终端将新建立的PDU会话的切换指示信息发送给控制面功能网元，并 由控制面功能网元发送给HSS+UDM。HSS+UDM在收到PDU会话的切换指示信息时将之前确定为可切换的DNN相同的PDU会话的切换指示信息设置为不可切换，并且通知该PDU会话对应的控制面功能网元。
第二种方式，所述终端接收来自至少一个控制面功能网元发送的所述建立的PDU会话的切换指示信息。至少一个控制面功能网元可以将自身确定的对应的PDU会话的切换指示信息发送给终端，例如，控制面功能网元根据PDU会话的辅助信息确定PDU会话的切换指示信息，并将确定的PDU会话的切换指示信息发送给终端，具体根据PDU会话的辅助信息确定PDU会话的切换指示信息的方法，参见方法200中的描述，或者至少一个控制面功能网元中每个控制面功能网元可以获取用户数据管理网元发送的每个控制面功能网元对应的PDU会话的切换指示信息，并发送给终端，本申请实施例对至少一个控制面功能网元中每个控制面功能网元如何获取自身PDU会话对应的切换指示信息并不做任何限定。
第三种方式，所述终端向第二控制面功能网元发送所述第一PDU会话的初始切换指示信息，所述初始切换指示信息用于确定所述第一PDU会话的切换指示信息；所述终端接收所述第二控制面功能网元发送的所述第一PDU会话的切换优先级信息。即终端将自身确定的第一PDU会话的初始切换指示信息发送给第二控制面功能网元，第二控制面功能网元可以对终端发送的第一PDU会话的初始切换指示信息进行调整，例如，第二控制面功能网元已经确定PDU会话1的切换指示信息，当第二控制面功能网元接收到终端发送的PDU会话2(第一PDU会话)的切换指示信息，并且第二控制面功能网元确定PDU会话1和PDU会话2属于同一个第二控制面功能网元以及同一个用户面功能控制网元，且第二控制面功能网元发现PDU会话1和PDU会话2的切换指示信息不同时，则第二控制面功能网元将PDU会话2的初始切换指示信息调整为PDU会话1的切换指示信息。即第二控制面功能网元可以根据终端发送的PDU会话的切换指示信息以及自身保存的PDU会话的切换指示信息调整终端发送的PDU会话的切换指示信息。又例如，第二控制面功能网元已经确定了PDU会话1的切换指示信息，当第二控制面功能网元接收到终端发送的PDU会话2的切换指示信息时，PDU会话1的切换指示信息与PDU会话2的切换指示信息相同，但是PDU会话1和PDU会话2的用户面功能网元不同，则第二控制面功能网元对PDU会话2的切换指示信息调整，调整为不同于PDU会话1的切换指示信息，例如切换指示信息用于指示PDU会话的优先级时，可以将PDU会话2的优先级调整成低于或高于PDU会话1的优先级。以上只是举例说明第二控制面功能网元具有调整PDU会话的切换指示信息的功能，具体，本申请实施例如何调整以及调整的策略并不作任何限定。
应理解，若终端确定所述第一PDU会话为所述目标PDU会话，则所述第一控制面功能网元即为所述第二控制面功能网元。
S320，所述终端根据所述切换指示信息在所述建立的PDU会话中确定目标PDU会话。可选地，该目标PDU会话可以是一个或多个，本申请实施例对此不作限制。
在本申请实施例中，切换指示信息至少存在两种不同指示作用，下面分两种情况来描述。
第一种情况，所述切换指示信息用于指示所述建立的PDU会话中每个PDU会话的切换优先级，其中，S320，包括：所述终端将所述建立的PDU会话中切换优先级最高的PDU会话确定为所述目标PDU会话。例如，切换优先级最高的PDU会话有一个，则该一个PDU会话即为目标PDU会话，切换优先级最高的PDU会话又两个以上，则该两个以上的PDU会话即为目标PDU会话。具体，切换优先级的概念参考方法200中的描述。
第二种情况，所述切换指示信息用于指示所述建立的PDU会话中每个PDU会话是否能够 切换，例如，切换指示信息可以是指示域，如，某一个PDU会话的指时域为1表示该PDU会话可以切换，某一个PDU会话的指示域为0表示该PDU会话不可以切换；其中，S320，包括：所述终端将所述切换指示信息指示的能够切换的PDU会话确定为所述目标PDU会话。即切换指示信息指示能够切换的PDU会话为一个，则该PDU会话即为目标PDU会话，若该切换指示信息指示能够切换的PDU会话为多个，则该多个PDU会话都可以为目标PDU会话，这多个目标PDU会话可以对应相同的控制面功能网关和用户面功能网元，例如，控制面功能网元可以是SMF+PGW-C,，用户面功能网元可以是UPF+PGW-U。
S330，所述终端经由第二网络的移动性管理实体设备向第一控制面功能网元发送所述目标PDU会话的标识。
作为一个可选实施例，S330，包括：所述终端向所述移动性管理实体设备发送所述目标PDU会话的标识以及所述目标PDU会话的DNN，所述目标PDU会话的DNN用于所述移动性管理实体设备确定所述第一控制面功能网元，以便于所述移动性管理实体设备向所述第一控制面功能网元发送所述目标PDU会话的标识。即终端可以向第二网络的移动性管理实体设备发送目标PDU会话的标识以及目标PDU会话的数据网络名称，第二网络的移动性管理实体设备根据所述目标PDU会话的数据网络名称可以确定该目标PDU会话对应的第一控制面功能网元，具体来说，用户数据管理网元可以向第二网络的移动性管理实体设备发送每个数据网络名称对应的控制面功能网元的标识，第二网络的移动性管理实体设备接收到用户管理网元发送的每个数据网络名称对应的控制面功能网元的标识之后，根据终端发送的目标PDU会话的数据网络名称，查找确定目标PDU会话对应的第一控制面功能网元，第二网络的移动性管理实体设备可以向该第一控制面功能网元发送给目标PDU会话的标识，这样，第一控制面功能网元就可以根据目标PDU会话的标识确定需要切换的PDU会话，例如，第二网络的移动性管理实体设备可以是MME。例如，终端向第二网络的移动性管理实体设备发送的目标PDU会话的ID以及该目标PDU会话的DNN 1，用户管理网元确定每个DNN下的目标PDU会话(优先级最高的PDU会话或者能够切换的PDU会话)，并且向第二网络的移动性管理实体发送DNN 1以及该DNN 1对应的控制面功能网元1(控制面功能网元1对应的PDU会话为目标PDU会话，该目标PDU会话的数据网络名称为DNN1)，也发送DNN 2以及该DNN 2对应的控制面功能网元2(控制面功能网元2对应的PDU会话为目标PDU会话，该目标PDU会话的数据网络名称为DNN 2)，第二网络的移动管理是可以确定DNN 1对应控制面功能网元1，则第二网络的移动管理设备可以向控制面功能网元1(第一控制面功能网元)发送该目标PDU会话的标识，这样，控制面功能网元1就可以确定所要切换的目标PDU会话。
作为一个可选实施例，所述终端向所述移动性管理实体设备发送所述目标PDU会话的标识以及所述目标PDU会话的数据网络名称，包括：所述终端向所述移动性管理实体设备发送第一请求消息，所述第一请求消息中携带所述目标PDU会话的标识以及所述目标PDU会话的数据网络名称，所述第一请求消息为附着请求消息或者会话建立请求消息。即终端确定目标PDU会话之后，可以在向第二网络的移动性管理实体设备发送附着请求消息时携带该目标PDU会话的标识以及目标PDU会话的数据网络名称，也可以在会话建立请求消息中携带该目标PDU会话的标识以及目标PDU会话的数据网络名称。本申请实施例对终端通过何种方式向第二网络的移动性管理实体设备发送目标PDU会话的标识以及目标PDU会话的数据网络名称并不作限定。
图4示出了本申请实施例提供的通信方法400，该方法400包括：
S410，终端向第二网络的移动性管理实体设备发送当前PDU会话对应的第一数据网络名称。这样，第二网络的移动性管理实体设备就可以确定当前PDU会话对应的控制面功能网元，具体确定方式参见方法300。第二网络的移动性管理实体设备可以向控制面功能网元发送第一网络名称对应的PDU会话(当前PDU会话)更新请求，控制面功能网元在接收到第一数据网络名称对应的会话更新请求后，控制面功能网元根据第一数据网络名称获取该第一数据网络名称对应的PDU会话，若对应的PDU会话为一个，则该PDU会话即为需要切换的会话。若对应的PDU会话为多个，该控制面功能网元选择一个PDU会话作为需要切换的PDU会话。该控制面功能网元可以任选一个PDU会话作为需要切换的PDU会话，或者根据PDU会话的辅助信息确定需要切换的PDU会话，比如，按会话对应的S-NSSAI确定需要切换的PDU会话，或者，若PDU会话的SSC模式为3，则按PDU会话建立的时间确定需要切换的PDU会话，或者，按PDU会话的IP地址版本确定需要切换的PDU会话等。或者，可选地，控制面功能网元还可从用户数据管理网元查询需要切换的PDU会话的会话标识，根据需要切换的PDU会话的会话标识确定需要切换的PDU会话，本申请实施例不做限定。。
可选地，S410，可以包括：终端向第二网络的移动性管理实体设备发送附着请求消息或者会话建立请求消息，附着请求消息或会话建立请求消息中携带当前PDU会话对应的第一数据网络名称。
可选地，若终端在附着请求消息中向第二网络的移动性管理实体设备发送当前PDU会话对应的第一数据网络名称，则控制面功能网元在确定需要切换的PDU会话之后，在附着流程中将PDU会话切换为PDN连接，若终端在会话建立请求消息中携带当前PDU会话对应的数据网络名称，则控制面功能网元在确定需要切换的PDU会话之后，在会话建立请求的流程中将PDU会话切换为PDN连接。切换完成之后，控制面功能网元将已经切换的PDU会话的标识向终端发送。例如控制面功能网元向终端发送协议配置选项(protocol configuration option，PCO)，PCO中携带已经切换的PDU会话的标识。
S420，终端接收控制面功能网元发送的已经切换的PDU会话的标识，根据PDU会话的标识确定已经切换了的PDU会话。可选地，终端接收控制面功能网元发送的PCO，在PCO中获取已经切换了的PDU会话的标识，根据PDU会话的标识确定已经切换了的PDU会话，这样UE可以将PDN连接与相应的会话关联起来。
图5示出了本申请实施例提供的通信方法500，该方法500包括：
S510，第一控制面功能网元接收终端发送的会话建立请求消息，所述会话建立请求消息用于请求建立第一协议数据单元PDU会话。
S520，所述第一控制面功能网元获取所述第一PDU会话的切换指示信息。可选地，所述切换指示信息用于指示所述第一PDU会话的优先级或者用于指示所述第一PDU会话是否能够切换。所述第一控制面功能网元获取所述第一PDU会话的第一切换指示信息有以下五种方式。
第一种方式，S510中的会话建立请求消息中携带所述第一PDU会话的切换指示信息。第一控制面功能网元可以在会话建立请求消息中确定第一PDU会话的切换指示信息。
在第一种方式下，第一控制面功能网元在获取到第一PDU会话的切换指示信息之后，第一控制面功能网元可以向用户数据管理网元发送该第一PDU会话的切换指示信息，当用户数据管理网元接收到多个控制面功能网元发送的多个PDU会话(多个PDU会话具有相同的DNN)中每个PDU会话对应的切换指示信息之后，用户数据管理网元可以进行保存，并在终端切换到第二网络时根据多个PDU会话中每个PDU会话对应的切换指示信息确定目标PDU会话，即 确定可以切换的PDU会话。第一控制面功能网元可以向接入和移动性管理功能设备发送第一PDU会话的切换指示信息，当接入和移动性管理功能设备接收到多个控制面功能网元发送的多个PDU会话(多个PDU会话具有相同的DNN)中每个PDU会话对应的切换指示信息之后，接入和移动性管理功能设备可以进行保存，并在切换时根据多个PDU会话中每个PDU会话对应的切换指示信息确定目标PDU会话，即确定可以切换的PDU会话。
可选地，第一控制面功能网元也可以将第一PDU会话的DNN以及第一控制面功能网元的标识向用户数据管理网元发送，第一控制面功能网元可以向用户数据管理网元发送第一PDU会话的会话信息，会话信息包括第一PDU会话的切换指示信息、第一PDU会话的DNN以及第一控制面控制网元的标识。这样，用户数据管理网元就可以保存第一PDU会话的会话信息，当用户数据管理网元接收到多个PDU会话(具有相同的DNN)的会话信息时，根据多个PDU会话的切换指示信息确定目标PDU会话，然后将目标PDU会话的DNN以及该目标PDU会话对应的控制面功能网元的标识发送给第二网络的移动性管理功能实体设备。
第二种方式，所述第一控制面功能网元接收来自终端发送的第一PDU会话的初始切换指示信息；所述第一控制面功能网元根据所述初始切换指示信息调整得到的所述第一PDU会话的切换指示信息；
在第二种方式下，所述第一控制面功能网元向所述终端或者用户数据管理网元或者接入和移动性管理功能发送所述第一PDU会话的切换指示信息。
第三种方式，所述第一控制面功能网元接收来自终端发送的第一PDU会话的初始切换指示信息；所述第一控制面功能网元将所述第一PDU会话的初始切换指示信息发送给用户数据管理网元，用户数据管理网元调整所述第一PDU会话的初始切换指示信息得到所述第一PDU会话的切换指示信息；数据数据管理网元将第一PDU会话的切换指示信息发送给第一控制面功能网元。
在第三种方式下，所述第一控制面功能网元向所述终端或者接入和移动性管理功能发送所述第一切换指示信息，既第一控制面功能网元将调整后的第一PDU会话的切换指示信息发送给终端。
第四种方式，所述第一控制面功能网元向用户数据管理网元发送所述第一PDU会话的辅助信息；数据数据管理网元根据所述第一PDU会话的辅助信息确定所述第一PDU会话的切换指示信息，然后向所述第一控制面功能网元发送所述第一PDU会话的切换指示信息，所述第一控制面功能网元接收所述用户数据管理网元发送的所述第一PDU会话的切换指示信息，所述第一PDU会话的辅助信息包括所述第一PDU会话对应的互联网协议IP地址版本、所述第一PDU会话对应的单网络切片辅助信息、所述第一PDU会话对应的会话和服务连续性SSC模式、所述第一PDU会话对应的分配和保留切换优先级ARP、所述第一PDU会话的业务类型和所述第一PDU会话对应的建立时间中的至少一项；
在第四种方式下，所述方法还包括：所述第一控制面功能网元向所述终端或接入和移动性管理功能发送所述第一PDU会话的第一切换指示信息。
第五种方式，所述第一控制面功能网元根据本地策略确定所述第一PDU会话的第二切换指示信息，所述第一控制面功能网元向用户数据管理网元发送所述第二切换指示信息，用户数据管理网元调整第二切换指示信息得到第一PDU会话的第一切换指示信息，并将第一切换指示信息发送给第一控制面功能网元。
在上述五种方式中，当第一控制面功能网元向终端发送所述第一PDU会话的切换指示信 息时，终端可以接收多个控制面功能网元发送的多个PDU会话(具有相同的DNN)的切换指示信息，终端可以根据多个PDU会话的切换指示信息在多个PDU会话中确定目标PDU会话，终端可以将该目标PDU会话的标识和该目标PDU会话的DNN向移动性管理功能实体设备发送。第一控制面功能网元向用户数据管理网元发送所述第一PDU会话的切换指示信息，可选地，第一控制面功能网元可以将第一PDU会话的DNN以及第一控制面功能网元的标识向用户数据管理网元发送，用户数据管理网元可以接收多个控制面功能网元发送的多个PDU会话(具有相同的DNN)的切换指示信息，用户数据管理网元可以根据多个PDU会话的切换指示信息在多个PDU会话中确定目标PDU会话，用户数据管理网元将该目标PDU会话的DNN以及该目标PDU会话对应控制面功能网元的标识向移动性管理功能实体设备发送。第一控制面功能网元向接入和移动性管理功能发送所述第一PDU会话的切换指示信息，可选地，第一控制面功能网元可以将第一PDU会话的DNN以及第一控制面功能网元的标识向接入和移动性管理功能发送，接入和移动性管理功能可以接收多个控制面功能网元发送的多个PDU会话(具有相同的DNN)的切换指示信息，接入和移动性管理功能可以根据多个PDU会话的切换指示信息在多个PDU会话中确定目标PDU会话，接入和移动性管理功能将该目标PDU会话的DNN以及该目标PDU会话对应控制面功能网元的标识向第二网络的移动性管理功能实体设备发送。
应理解，在本申请实施例中，方法200至方法500中，可能采用了相同的名词，但是在不同的方法中，可以表达为不同的意思，例如，第一控制面功能网元可以是任意一个控制面功能网元，在方法200至方法500，并不表示的是同一个设备，也即本申请实施例中，“第一”，“第二”，并不特指某一个，而是泛指任何一个。
下面结合附图详细描述本申请实施例提供的通信方法。方法600-方法900中，以终端为UE，接入和移动性管理功能设备为AMF，移动性管理设备为MME，控制面功能网元为SMF+PGW-C，用户数据管理网元为HSS+UDM，第一网络为5G网络，第二网络为4G网络，切换指示信息指示的是切换优先级为例进行说明，但本申请实施例不限于此。
下面分为MME与AMF之间N26接口是否存在接口进行描述。在下面的描述中，切换指示信息可以指示切换优先级，在终端从5G系统切换到演进的分组网络系统(evolved packet system，EPS)时，根据DNN相同的PDU会话对应的切换指示信息确定切换到EPS的PDU会话。在一种实现中，为了选择目标PDU会话，UE向SMF+PGW-C发送切换优先级，SMF可以确定最终的切换优先级，并通过发送回UE。如果同一SMF+PGW-C以及同一UPF+PGW-U服务多个DNN相同的PDU会话，则SMF+PGW-C可以将多个PDU会话的优先级设置为相同的值。
对于没有N26接口的部署场景中，SMF+PGW-C将切换优先级、DNN以及SMF+PGW-C ID发送给UDM+HSS，当UE移动到EPS时，UE选择切换优先级最高的PDU会话，并且向MME发送PDN连接建立请求消息，并且在PCO中携带PDU会话的ID。对于一个DNN，HSS+UDM向MME发送切换优先级最高的SMF+PGW-C ID，从而将切换优先级最高的PDU会话切换为EPS中对应的PDN连接。
对于有N26接口的部署场景中，SMF+PGW-C将切换优先级与会话上下文一起发送给AMF，AMF选择最高切换优先级的PDU会话，并将该PDU会话的上下文转发给MME，这样，具有最高切换优先级的PDU会话将会相应地被切换到EPS。
这样方案对MME没有影响，并且对HSS+UDM的影响也很小。有了这个方案，相同的SMF+PGW-C以及相同UPF+PGW-U所服务的相同DNN的PDU会话可以切换至EPS，这样的选择可以反映用户的需求。在这个方案中，UE可以在PDU会话建立时确定切换优先级，例如，根据 方法300中的方式确定切换优先级。切换优先级可以由UE确定，切换优先级也可以由SMF+PGW-C和/或HSS+UDM确定。当PDU会话建立时，SMF+PGW-C可以首先确定该PDU会话是否可以切换至4G网络，例如，当一个PDU会话具有SSC模式2时，SMF+PGW-C可以确定该PDU会话没有必要切换至4G网络。当SMF+PGW-C向HSS+UDM注册SMF+PGW-C ID以及DNN时，SMF+PGW-C可以指示PDU会话是否可以切换至4G网络，此外，SMF+PGW-C可以将其他的辅助信息发送给HSS+UDM，例如，PDU会话的S-NSSAI、IP地址的版本、SSC模式、ARP、业务类型和建立时间等，以便于HSS+UDM根据这些辅助信息确定切换优先级。
当HSS+UDM接收到PDU会话的注册时，如果同一DNN的多个PDU会话可以切换至4G网络，HSS+UDM根据切换辅助信息确定多个PDU会话的切换优先级，例如，对于SSC模式3的PDU会话，HSS+UDM可以标记同一DNN的最新的PDU会话具有更高的优先级，对于不同的IP版本，HSS+UDM可以配置默认策略来选择PDU会话等。
对于没有N26接收的部署场景中，当UE移动到EPS，UE在向MME发送的PDN会话建立请求消息中仅携带DNN，UE不选择待切换的PDU会话，因此，UE不在PCO中携带PDU会话ID，对于一个DNN，HSS+UDM可以发送最高优先级的PDU会话对应的SMF+PGW-C ID给MME，在EPS中，PDN连接建立完成后，SMF+PGW-C可以通过PCO向终端指示该DNN已经建立的PDU会话的ID，使得UE可以将PDN连接与相应的会话关联起来。对于有N26部署的场景中，AMF可以确定能够切换到4G的会话，处理方式类似HSS+UDM。
下图中图6至图9是没有部署N26接口的场景，图10至图13是部署N26接口的场景。
图6示出了本申请实施例提供的通信方法600，包括：
S601，UE在5G网络建立PDU会话时确定PDU会话的切换指示信息，建立的PDU会话中每个PDU会话具有相同的DNN。其中，PDU会话的切换指示信息是切换优先级或者是指示PDU会话能否切换。UE确定PDU会话的切换指示信息的方法参见300。
S602，UE将建立的PDU会话的切换指示信息携带在会话建立请求消息中向AMF发送，或者会话建立请求消息包括PCO，UE可以将建立的PDU会话的切换指示信息携带在PCO。UE可以在每确定一个PDU会话的切换指示信息之后，向AMF通过会话建立请求消息向AMF发送每个PDU会话的切换指示信息。
S603，AMF接收UE发送的会话建立请求消息，不解析该会话建立请求消息中包括的PDU会话的切换指示信息，直接通过非接入层(non-access stratum，NAS)消息转发给SMF+PGW-C，即一个会话建立请求消息中携带一个PCO，该PCO包括PDU会话的切换指示信息，为了方面描述，图6中仅示出一个SMF+PGW-C，在实际应用过程中可以有多个SMF+PGW-C，即AMF将每个SMF+PGW-C对应的PDU会话的切换指示信息发送给对应的SMF+PGW-C。
S604，SMF+PGW-C接收AMF发送的非接入层消息，在非接入层消息中获取PDU会话的切换指示信息，可选地，SMF+PGW-C可以对接收到的PDU会话的切换指示信息进行调整，并确定最终的PDU会话的切换指示信息。例如，SMF+PGW-C接收到终端发送的PDU会话1和PDU会话2的切换指示信息，终端发送的PDU会话1和PDU会话2的切换指示信息不同，PDU会话1和PDU会话2的UPF+PGW-U相同，则SMF+PGW-C可以将PDU会话1和PDU会话2的切换指示信息调整成一样的；又例如，终端发送的PDU会话1和PDU会话2的切换指示信息相同，PDU会话1和PDU会话2的UPF+PGW-U不同，则SMF+PGW-C可以将PDU会话1和PDU会话2的切换指示信息调整为不相同。
S605，当SMF+PGW-C没有调整PDU会话的切换指示信息时，则直接将接收到的PDU会话 的会话信息发送给HSS+UDM，PDU会话的会话信息包括PDU会话的切换指示信息、SMF+PGW-C的标识以及该PDU会话的DNN，例如SMF+PGW-C的标识可以是SMF+PGW-C ID；当SMF+PGW-C调整PDU会话的切换指示信息之后，则将调整后的切换指示信息、SMF+PGW-C的标识以及该PDU会话的DNN发送给HSS+UDM。应理解，这里的DNN可以是SMF+PGW-C获知的或者是终端发送给SMF+PGW-C的，本申请实施例对此不作限制。
S606，HSS+UDM接收到至少一个SMF+PGW-C发送的终端在5G网络建立的PDU会话的会话信息之后，存储该建立PDU会话的会话信息。
可选地，若切换指示信息指示的是PDU会话能否切换，并且当切换指示信息指示该PDU会话可切换到4G网络时，HSS+UDM检查相同DNN的其他PDU会话，若HSS+UDM保存了相同DNN的其他PDU会话，且这些其他的PDU会话中存在一个已被标识为可切换到4G网络，HSS+UDM确定这两个可切换的PDU会话中哪个可切换到4G网络。HSS+UDM可以根据辅助信息(参见前述的辅助信息)确定哪个PDU会话可切换。若HSS+UDM确定之前建立的已被表示为可切换的PDU会话变为不可切换，则HSS+UDM通知该PDU会话对应的SMF+PGW-C，SMF+PGW-C将该PDU会话设置为不可切换。
S607，HSS+UDM可以向至少一个SMF+PGW-C返回响应信息，用于指示SMF+PGW-C发送的PDU会话的会话信息被接受。
S608，SMF+PGW-C执行PDU会话建立，SMF+PGW-C创建一个上下文，并发送给AMF。
S609，UE、接入网网元、AMF、SMF+PGW-C等执行后续的PDU会话建立流程，此步骤为现有技术，在此不详细描述。
S610，若SMF+PGW-C修改了PDU会话的切换指示信息，则将修改后的切换指示信息发送给终端，如果SMF+PGW-C没有修改PDU会话的切换指示信息，则向终端返回一个确认消息，用于指示UE发送的切换指示信息被接受，可选地，该若切换指示信息没有被SMF+PGW-C修改，则确认消息中仍然可以携带UE向SMF+PGW-C发送的PDU会话的切换指示信息。
S611，当UE移动到4G网络时，若UE建立同一DNN的多个PDU会话，则UE根据同一DNN的多个PDU会话的切换指示信息确定目标PDU会话，该目标PDU会话是UE期望切换至4G的PDU会话。当切换指示信息是切换优先级时，UE确定相同DNN的多个PDU会话中优先级最高的PDU会话作为目标PDU会话。当切换指示信息是能否切换时，UE确定切换指示信息指示的“可切换”到4G的PDU会话为目标PDU会话。
S612，UE向MME发送第一请求消息，该第一请求消息中携带目标PDU会话的ID以及该目标PDU会话的DNN。该第一请求消息可以是附着请求消息，也可以是PDN会话建立请求消息。其中，目标PDU会话的ID包含在PCO中。
S613，若第一请求消息是附着请求，则MME在接收到第一请求消息之后，向HSS+UDM发送第二请求消息，用于向HSS+UDM请求会话信息，会话信息可以包括DNN以及DNN对应的SMF+PGW-C ID。
S614，HSS+UDM根据保存的PDU会话的会话信息，根据同一DNN的不同PDU会话的切换指示信息，在同一DNN的不同PDU会话中确定该DNN中可以切换的PDU会话，即为该DNN对应的目标PDU会话，并确定该目标会话对应的SMF+PGW-C ID。当切换指示信息是切换优先级时，HSS+UDM确定相同DNN的多个PDU会话中优先级最高的PDU会话作为目标PDU会话。当切换指示信息是能否切换时，HSS+UDM确定切换指示信息指示的“可切换”到4G的PDU会话为目标PDU会话。
S615，HSS+UDM向MME发送DNN对应的目标PDU会话的DNN以及SMF+PGW-C ID。即HSS+UDM保存了多个DNN的PDU会话的会话信息，HSS+UDM可以确定每个DNN下的目标PDU会话以及每个DNN下目标PDU会话对应的SMF+PGW-C ID。然后将每个DNN下目标PDU会话的DNN以及该目标PDU会话对应的SMF+PGW-C ID向MME发送，例如，MME收到的是DNN1对应SMF+PGW-C1以及DNN2对应SMF+PGW-C 2。
S616，MME接收到UE发送的第一请求消息之后，根据第一请求消息中携带的该目标PDU会话的DNN以及S615中得到的每个DNN下目标PDU会话的DNN以及该目标PDU会话对应的SMF+PGW-C ID，确定第一请求消息中目标PDU会话的DNN对应的SMF+PGW-C ID，根据SMF+PGW-C ID确定SMF+PGW-C。
S617，MME向SMF+PGW-C发送会话建立请求消息，该会话建立请求消息中包括PCO，PCO携带了目标PDU会话的ID和该目标PDU会话的DNN。
S618，SMF+PGW-C根据MME发送的目标PDU会话的ID以及该目标PDU会话的DNN确定需要切换的PDU会话，若SMF+PGW-C保存了该DNN以及该DNN对应的会话，则选出该PDU会话进行切换，若SMF+PGW-C查找发送该目标PDU会话不存在，则拒绝该PDU会话。
图7示出了本申请实施例提供的通信方法700，包括：
S701，UE向AMF发送会话建立请求消息。
S702，AMF向SMF+PGW-C发送会话建立请求消息。
S703，SMF+PGW-C确定PDU会话的切换指示信息。例如，SMF+PGW-C可以根据前述的辅助信息确定PDU会话的切换指示信息。
S704，同S605。可选地，SMF+PGW-C可以向HSS+UDM发送辅助信息，用于HSS+UDM在发现来自不同的SMF+PGW-C的切换指示信息存在冲突时，根据辅助信息调整冲突。
可选地，S705，HSS+UDM可以调整PDU会话的切换指示信息，假设HSS+UDM已经接收到来自第一SMF+PGW-C的PDU会话1的优先级为2，当HSS+UDM接收到第二SMF+PGW-C发送的PDU会话2的优先级也为2，并且PDU会话1和PDU会话2具有相同的DNN，则HSS+UDM可以根据辅助信息调整PDU会话1和\或PDU会话2的优先级。比如，HSS+UDM可将PDU会话2的优先级调整为高于或低于PDU会话1的优先级。
S706，HSS+UDM将PDU会话的会话信息进行存储。
S707，若HSS+UDM没有调整PDU会话的切换指示信息，则HSS+UDM向SMF+PGW-C发送响应信息，用于指示SMF+PGW-C发送的PDU会话的切换指示信息被接受，可选地，在响应消息中可携带被接受的PDU会话的切换指示信息；若HSS+UDM调整了PDU会话的切换指示信息，则向SMF+PGW-C在响应消息中发送调整后的PDU会话的切换指示信息。
S708-S718同S608至S618。
图8示出了本申请实施例提供的通信方法800，包括：
S801，同S701。
S802，同S702。
S803，SMF+PGW-C向HSS+UDM发送辅助信息、SMF+PGW-C ID以及PDU会话的DNN，其中可以是前述方法中的辅助信息。
S804，HSS+UDM根据接收到的辅助信息确定PDU会话的切换指示信息。
S805，HSS+UDM存储PDU会话的切换指示信息、SMF+PGW-C ID以及PDU会话的DNN。
S806，HSS+UDM向SMF+PGW-C发送响应消息，该响应消息中携带PDU会话的指示信息。
应理解，这里HSS+UDM可以接收多个SMF+PGW-C发送的PDU会话辅助信息SMF+PGW-C ID、以及PDU会话的DNN。HSS+UDM将确定的每个SMF+PGW-C对应的PDU会话的切换指示信息发送给相应的SMF+PGW-C。
S807-S817同S708-S718。
图9示出了本申请实施例提供的通信方法900，包括：
方法900中的S910之前的步骤可以同方法700中的S701-S709，也可以同方法800中的S801-S808，在此只描述方法900中的S910之后的步骤。
S910，当UE移动至4G网络时，UE向MME发送第一请求消息，该第一请求消息中携带当前PDU会话的DNN，该第一请求消息可以是附着请求消息或者会话建立请求消息。
S911，同S812。
S912，同S813。
S913，同S814。
S914，同S815。
S915，MME向SMF+PGW-C发送会话建立请求消息，该会话建立请求消息中携带当前PDU会话的DNN。
S916，若属于SMF+PGW-C该DNN对应的PDU会话只有一个，则SMF+PGW-C将该PDU会话确定为切换的PDU会话，若属于SMF+PGW-C该DNN对应的PDU会话有多个，则SMF+PGW-C可以将多个PDU会话中确定一个PDU会话为切换的PDU会话。
S917，SMF+PGW-C将切换的PDU会话的标识发送给UE，这样UE就根据PDU会话的标识与PDN连接相关联。可选地，该PDU会话的标识通过PCO发送给UE。
上面图6至图9示出了MME与AMF之间没有部署N26接口时的通信方法，下面结合图10至图13描述MME与AMF部署N26接口的通信方法。
图10示出了本申请实施例提供的通信方法1000，包括：
S1001，同S601。
S1002，同S602。
S1003，同S603。
S1004，同S604。
S1005，SMF+PGW-C存储PDU会话的切换指示信息。
S1006，SMF+PGW-C向AMF发送会话建立响应消息。
S1007，同S609
S1008，当UE处于空闲态时，并且UE移动到4G网络，则UE可以向MME发送跟踪区更新(tracking area update,TAU)请求消息。
S1009，当MME接收到TAU请求消息之后，向AMF发送第一上下文请求消息，用于向AMF请求将UE的上下文信息发送给MME，所述UE的上下文信息包括会话上下文。
S1010，AMF接收到MME发送的第一上下文请求消息之后，根据第一上下文请求消息向SMF+PGW-C发送第二上下文请求消息，用于向SMF+PGW-C请求会话上下文。
S1011，SMF+PGW-C向AMF发送可切换到4G的PDU会话的会话信息，例如会话信息包括该PDU会话的切换指示信息、该PDU会话对应的PDN连接的缺省承载标识、该PDU会话的DNN以及SMF+PGW-C ID等信息。
S1012，AMF可以接收到多个SMF+PGW-C中每个SMF+PGW-C发送的PDU会话的会话信息， AMF可以在这些会话信息在同一DNN的PDU会话中确定目标PDU会话作为切换的PDU会话。
S1013，AMF将目标PDU会话的会话信息发送给MME。
S1014，MME、AMF、UE等执行后续的切换流程，该步骤为现有技术，本申请实施例在此不详细描述。
图11示出了本申请实施例提供的通信方法1100，包括：
S1101-S1107同S1001-S1007。
S1108，当UE处于数据连接态时，当gNB发现UE的位置发生变化时，gNB向AMF发送切换请求，用于请求当前的PDU会话需要切换。
S1109，AMF向SMF+PGW-C发送上下文请求消息，用于获取UE的上下文。
S1110，同S1011。
S1111，同S1012。
S1112，同S1013。
S1113，同S1014。
图12示出了本申请实施例提供的通信方法1200，包括：
方法1200中的S1204之后的步骤可以同方法1000中的S1008-S1014，也可以同方法1100中的S1106-S1113，在此只描述方法1200中的S1204之前的步骤。
S1201，同S801。
S1202，同S802。
S1203，SMF+PGW-C根据PDU会话的辅助信息确定PDU会话的切换指示信息，例如辅助信息可以是前述的辅助信息。
S1204，同S1105。
图13示出了本申请实施例提供的通信方法1300，包括：
方法1300中的S1305之后的步骤可以同方法1000中的S1006-S1014，也可以同方法1100中的S1106-S1113，在此只描述方法1300中的S1305之前的步骤。
S1301，同S801。
S1302，同S802。
S1303，SMF+PGW-C向HSS+UDM发送会话注册请求消息，该注册请求消息包括辅助信息，该辅助信息可以是前述的辅助信息。
S1304，HSS+UDM接收SMF+PGW-C发送的注册请求消息，在该注册请求消息中获取辅助信息，根据辅助信息确定PDU会话的切换指示信息。这样HSS+UDM可以确定多个SMF+PGW-C对应的PDU会话的切换指示信息。
S1305，HSS+UDM将每个SMF+PGW-C对应的PDU会话的切换指示信息通过会话注册请求消息的响应消息向相应的SMF+PGW-C发送。
应理解，本申请实施例对上述方法200至方法1300中各个步骤的顺序并不作任何限定，每个方法中的步骤序号并不代表先后顺序，在实际应用中可以对每个方法中的步骤的顺序进行调整，例如，每个方法中的步骤的先后顺序可以根据内在逻辑确定。
上文中结合图1至图13，详细描述了根据本申请实施例的通信方法，下面将结合图14至图19，详细描述根据本申请实施例的通信装置。
图14示出了本申请实施例提供的通信装置1400，所述装置1400可以是前述的网络设备，网络设备可以是用户数据管理网元或者接入和移动性管理功能设备，该装置1400包括：
处理单元1410，用于根据终端在第一网络建立的协议数据单元PDU会话的切换指示信息，在所述建立的PDU会话中确定目标PDU会话，其中所述建立的PDU会话中每个PDU会话具有相同的数据网络名称DNN；
收发单元1420，用于向第二网络的移动性管理实体设备发送所述目标PDU会话的会话信息。
作为一个可选实施例，所述切换指示信息用于指示所述建立的PDU会话中每个PDU会话的切换优先级，所述处理单元1410具体用于：将所述建立的PDU会话中切换优先级最高的PDU会话确定为所述目标PDU会话。
作为一个可选实施例，所述切换指示信息用于指示所述建立的PDU会话中每个PDU会话是否能够切换；所述处理单元1410具体用于：在所述切换指示信息指示的能够切换的PDU会话只有一个的情况下，确定该能够切换的PDU会话为所述目标PDU会话；在所述切换指示信息指示能够切换的PDU会话至少有两个的情况下，在该至少两个PDU会话中确定所述目标PDU会话。
作为一个可选实施例，所述处理单元1410具体用于：若所述至少两个PDU会话属于同一个控制面功能网元，将该至少两个会话确定为所述目标会话；若所述至少两个PDU会话属于不同的控制面功能网元，根据该至少两个PDU会话的该至少两个PDU会话中每个PDU会话的辅助信息，在该至少两个PDU会话中确定目标PDU会话。
作为一个可选实施例，所述装置1400为用户数据管理网元，所述收发单元1420还用于：在所述根据终端在第一网络中建立的协议数据单元PDU会话的切换指示信息，在所述建立的PDU会话中确定目标PDU会话之前，接收来自第一控制面功能网元发送的所述建立的PDU会话中第一PDU会话的辅助信息；
所述处理单元1410还用于：根据所述辅助信息确定所述第一PDU会话的切换指示信息。
作为一个可选实施例，所述辅助信息包括以下至少一项：PDU会话对应的互联网协议IP地址版本、PDU会话对应的单网络切片辅助信息、PDU会话对应的会话和服务连续性SSC模式、PDU会话对应的分配和保留切换优先级ARP、PDU会话的业务类型和PDU会话对应的建立时间。
作为一个可选实施例，所述收发单元1420还用于：在所述根据终端在第一网络中建立的协议数据单元PDU会话的切换指示信息，在所述建立的PDU会话中确定目标PDU会话之前，接收来自至少一个控制面功能网元发送的终端在第一网络建立的PDU会话的切换指示信息。
作为一个可选实施例，所述装置1400为用户数据管理网元，所述收发单元1420还用于：在所述根据终端在第一网络中建立的协议数据单元PDU会话的切换指示信息，在所述建立的PDU会话中确定目标PDU会话之前，接收来自第二控制面功能网元发送的终端在第一网络建立的PDU会话中的第二PDU会话的初始切换指示信息；所述处理单元1410还用于：调整所述初始切换指示信息得到所述第二PDU会话的切换指示信息；所述收发单元1420还用于：向所述第二控制面功能网元发送所述第二PDU会话的切换指示信息。
作为一个可选实施例，所述目标PDU会话的会话信息包括所述目标PDU会话对应的控制面功能网元的标识以及所述目标PDU会话的DNN。
应理解，这里的装置1400以功能单元的形式体现。这里的术语“单元”可以指应用特有集成电路(application specific integrated circuit，ASIC)、电子电路、用于执行一个或多个软件或固件程序的处理器(例如共享处理器、专有处理器或组处理器等)和存储器、合并逻辑电路和/或其它支持所描述的功能的合适组件。在一个可选例子中，本领域技术人员 可以理解，装置1400可以具体为上述方法实施例中的网络设备，装置1400可以用于执行上述方法实施例中与终端对应的各个流程和/或步骤，为避免重复，在此不再赘述。
图15示出了本申请实施例提供的通信装置1500，所述装置1500可以是前述终端，该装置1500包括：
获取单元1510，用于获取在第一网络中建立的协议数据单元PDU会话的切换指示信息，所述建立的PDU会话中每个PDU会话具有相同的数据网络名称DNN；
处理单元1520，用于根据所述建立的PDU会话的切换指示信息，在所述建立的PDU会话中确定目标PDU会话；
收发单元1530，用于经由第二网络的移动性管理实体设备向第一控制面功能网元发送所述目标PDU会话的标识。
作为一个可选实施例，所述切换指示信息用于指示所述建立的PDU会话中每个PDU会话的切换优先级，所述处理单元1520具体用于：将所述建立的PDU会话中切换优先级最高的PDU会话确定为所述目标PDU会话。
作为一个可选实施例，所述切换指示信息用于指示所述建立的PDU会话中每个PDU会话是否能够切换；所述处理单元1520具体用于：将所述建立的PDU会话中能够切换的PDU会话确定为所述目标PDU会话。
作为一个可选实施例，所述收发单元1530具体用于：向所述移动性管理实体设备发送所述目标PDU会话的标识以及所述目标PDU会话的DNN，所述目标PDU会话的DNN用于所述移动性管理实体设备确定所述第一控制面功能网元，以便于所述移动性管理实体设备向所述第一控制面功能网元发送所述目标PDU会话的标识。
作为一个可选实施例，所述收发单元1530具体用于：向所述移动性管理实体设备发送第一请求消息，所述第一请求消息中携带所述目标PDU会话的标识以及所述目标PDU会话的DNN，所述第一请求消息为附着请求消息或者会话建立请求消息。
作为一个可选实施例，所述获取单元1510具体用于：接收来自至少一个控制面功能网元发送的所述建立的PDU会话的切换指示信息。
作为一个可选实施例，所述收发单元1530还用于：向第二控制面功能网元发送所述第一PDU会话的初始切换指示信息，所述初始切换指示信息用于确定所述第一PDU会话的切换指示信息；接收所述第二控制面功能网元发送的所述第一PDU会话的切换指示信息。
应理解，这里的装置1500以功能单元的形式体现。这里的术语“单元”可以指应用特有集成电路(application specific integrated circuit，ASIC)、电子电路、用于执行一个或多个软件或固件程序的处理器(例如共享处理器、专有处理器或组处理器等)和存储器、合并逻辑电路和/或其它支持所描述的功能的合适组件。在一个可选例子中，本领域技术人员可以理解，装置1500可以具体为上述方法实施例中的终端，装置1500可以用于执行上述方法实施例中与终端对应的各个流程和/或步骤，为避免重复，在此不再赘述。
图16示出了本申请实施例提供的通信装置1600，所述装置1600可以是前述第一控制面功能网元，该装置1600包括：
收发单元1610，用于接收终端发送的会话建立请求消息，所述会话建立请求消息用于请求建立第一协议数据单元PDU会话；
获取单元1620，用于获取所述第一PDU会话的切换指示信息。
作为一个可选实施例，所述切换指示信息用于指示所述第一PDU会话的优先级或者用于 指示所述第一PDU会话是否能够切换。
作为一个可选实施例，所述会话建立请求消息包括所述第一PDU会话的切换指示信息，所述获取单元1620具体用于：在所述会话建立请求消息中获取所述第一PDU会话的切换指示信息；所述收发单元1610还用于：向用户数据管理网元或接入和移动性管理功能设备发送所述第一PDU会话的切换指示信息。
作为一个可选实施例，所述获取单元1620具体用于：获取所述第一PDU会话的初始切换指示信息；所述装置1600还包括：处理单元，用于获取根据所述初始切换指示信息调整得到的所述第一PDU会话的切换指示信息；收发单元1610还用于：向所述终端或者用户数据管理网元或者接入和移动性管理功能设备发送所述第一PDU会话的切换指示信息。
作为一个可选实施例，所述收发单元1610还用于：向用户数据管理网元发送所述第一PDU会话的辅助信息；接收所述用户数据管理网元发送的所述第一PDU会话的切换指示信息，所述第一PDU会话的切换指示信息根据所述第一PDU会话的辅助信息确定，所述第一PDU会话的辅助信息包括所述第一PDU会话对应的互联网协议IP地址版本、所述第一PDU会话对应的单网络切片辅助信息、所述第一PDU会话对应的会话和服务连续性SSC模式、所述第一PDU会话对应的分配和保留切换优先级ARP、所述第一PDU会话的业务类型和所述第一PDU会话对应的建立时间中的至少一项；向所述终端或接入和移动性管理功能设备发送所述第一PDU会话的切换指示信息。
作为一个可选实施例，所述收发单元1610还用于：向用户数据管理网元发送所述第一PDU会话的数据网络名称DNN以及所述装置的标识。
应理解，这里的装置1600以功能单元的形式体现。这里的术语“单元”可以指应用特有集成电路(application specific integrated circuit，ASIC)、电子电路、用于执行一个或多个软件或固件程序的处理器(例如共享处理器、专有处理器或组处理器等)和存储器、合并逻辑电路和/或其它支持所描述的功能的合适组件。在一个可选例子中，本领域技术人员可以理解，装置1600可以具体为上述方法实施例中的第一控制面功能网元或第二控制面功能网元，装置1600可以用于执行上述方法实施例中与第一控制面功能网元或第二控制面功能网元对应的各个流程和/或步骤，为避免重复，在此不再赘述。
上述装置1400与方法实施例中的网络设备完全对应，上述装置1500与方法实施例中终端完全对应，上述装置1600与方法实施例中的第一控制面功能网元或第二控制面功能网元完全对应，由相应的单元执行相应的步骤，例如收发单元方法执行方法实施例中收发步骤，除收发外的其它步骤可以由处理模块执行。具体模块的功能可以参考相应的方法实施例，不再详述。
上述各个方案的装置1400-装置1600具有实现上述方法中网络设备、终端、第一控制面功能网元或第二控制面功能网元执行的相应步骤的功能；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；例如发送单元可以由发射机替代，接收单元可以由接收机替代，其它单元，如确定单元等可以由处理器替代，分别执行各个方法实施例中的收发操作以及相关的处理操作。
在本申请的实施例，图14-16中的装置也可以是芯片或者芯片系统，例如：片上系统(System on Chip,SoC)。对应的，接收单元和发送单元可以是该芯片的收发电路，在此不做限定。
图17示出了本申请实施例提供的又一通信装置1700。该装置1700包括处理器1710、收 发器1720和存储器1730。其中，处理器1710、收发器1720和存储器1730通过内部连接通路互相通信，该存储器1730用于存储指令，该处理器1710用于执行该存储器1730存储的指令，以控制该收发器1720发送信号和/或接收信号。
其中，处理器1710用于根据终端在第一网络建立的协议数据单元PDU会话的切换指示信息，在所述建立的PDU会话中确定目标PDU会话，其中所述建立的PDU会话中每个PDU会话具有相同的数据网络名称DNN；收发器1720用于向第二网络的移动性管理实体设备发送所述目标PDU会话的会话信息。
应理解，装置1700可以具体为上述方法实施例中的网络设备，并且可以用于执行上述方法实施例中网络设备对应的各个步骤和/或流程。可选地，该存储器1730可以包括只读存储器和随机存取存储器，并向处理器提供指令和数据。存储器的一部分还可以包括非易失性随机存取存储器。例如，存储器还可以存储设备类型的信息。该处理器1710可以用于执行存储器中存储的指令，并且当该处理器1710执行存储器中存储的指令时，该处理器1710用于执行上述与该终端对应的方法实施例的各个步骤和/或流程。
图18示出了本申请实施例提供的又一通信装置1800。该装置1800包括处理器1810、收发器1820和存储器1830。其中，处理器1810、收发器1820和存储器1830通过内部连接通路互相通信，该存储器1830用于存储指令，该处理器1810用于执行该存储器1830存储的指令，以控制该收发器1820发送信号和/或接收信号。
其中，收发器1820用于获取在第一网络中建立的协议数据单元PDU会话的切换指示信息，所述建立的PDU会话中每个PDU会话具有相同的数据网络名称DNN；处理器1810用于根据所述建立的PDU会话的切换指示信息，在所述建立的PDU会话中确定目标PDU会话；收发器1820用于经由第二网络的移动性管理实体设备向第一控制面功能网元发送所述目标PDU会话的标识。
应理解，装置1800可以具体为上述方法实施例中的终端，并且可以用于执行上述方法实施例中终端对应的各个步骤和/或流程。可选地，该存储器1830可以包括只读存储器和随机存取存储器，并向处理器提供指令和数据。存储器的一部分还可以包括非易失性随机存取存储器。例如，存储器还可以存储设备类型的信息。该处理器1810可以用于执行存储器中存储的指令，并且当该处理器1810执行存储器中存储的指令时，该处理器1810用于执行上述与该第一网络的第一类型的接入网网元对应的方法实施例的各个步骤和/或流程。
图19示出了本申请实施例提供的又一通信装置1900。该装置1900包括处理器1910、收发器1920和存储器1930。其中，处理器1910、收发器1920和存储器1930通过内部连接通路互相通信，该存储器1930用于存储指令，该处理器1910用于执行该存储器1930存储的指令，以控制该收发器1920发送信号和/或接收信号。
其中，收发器1920用于接收终端发送的会话建立请求消息，所述会话建立请求消息用于请求建立第一协议数据单元PDU会话；收发器1920还用于获取所述第一PDU会话的切换指示信息。
应理解，装置1900可以具体为上述方法实施例中的第一控制面功能网元或第二控制面功能网元，并且可以用于执行上述方法实施例中第一控制面功能网元或第二控制面功能网元对应的各个步骤和/或流程。可选地，该存储器1930可以包括只读存储器和随机存取存储器，并向处理器提供指令和数据。存储器的一部分还可以包括非易失性随机存取存储器。例如，存储器还可以存储设备类型的信息。该处理器1910可以用于执行存储器中存储的指令，并且 当该处理器1910执行存储器中存储的指令时，该处理器1910用于执行上述与该第一网络的核心网网元对应的方法实施例的各个步骤和/或流程。
应理解，上述的收发器可以包括发射机和接收机。收发器还可以进一步包括天线，天线的数量可以为一个或多个。存储器可以是一个单独的器件，也可以集成在处理器中。上述的各个器件或部分器件可以集成到芯片中实现，如集成到基带芯片中实现。
在本申请的实施例，图17-图19中的收发器也可以是通信接口，在此不做限定。
在本申请的实施例中，第一控制面功能网元或者第二控制面功能网元即可以是物理上的实体设备，也可是是虚拟的功能网元，在此不做限定。
在本申请的各实施例中，为了方面理解，进行了多种举例说明。然而，这些例子仅仅是一些举例，并不意味着是实现本申请的最佳实现方式。
在本申请的各实施例中，为了方便的描述，采用了请求消息，响应消息以及其他各种消息的名称。然而，这些消息仅仅是以举例方式说明需要携带的内容或者实现的功能，消息的具体名称并不对本申请的做出限定，例如：还可以是第一消息，第二消息，第三消息等。这些消息可以是具体的一些消息，可以是消息中的某些字段。这些消息还可以代表各种服务化操作。
也应理解，在本申请实施例中，上述装置的处理器可以是中央处理单元(central processing unit，CPU)，该处理器还可以是其他通用处理器、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、分立门或者晶体管逻辑器件、分立硬件组件等。通用处理器可以是微处理器或者该处理器也可以是任何常规的处理器等。
在实现过程中，上述方法的各步骤可以通过处理器中的硬件的集成逻辑电路或者软件形式的指令完成。结合本申请实施例所公开的方法的步骤可以直接体现为硬件处理器执行完成，或者用处理器中的硬件及软件单元组合执行完成。软件单元可以位于随机存储器，闪存、只读存储器，可编程只读存储器或者电可擦写可编程存储器、寄存器等本领域成熟的存储介质中。该存储介质位于存储器，处理器执行存储器中的指令，结合其硬件完成上述方法的步骤。为避免重复，这里不再详细描述。
在上述实施例中，可以全部或部分地通过软件、硬件、固件或者其任意组合来实现。当使用软件实现时，可以全部或部分地以计算机程序产品的形式实现。所述计算机程序产品包括一个或多个计算机指令。在计算机上加载和执行所述计算机程序指令时，全部或部分地产生按照本申请实施例所述的流程或功能。所述计算机可以是通用计算机、专用计算机、计算机网络、或者其他可编程装置。所述计算机指令可以存储在计算机可读存储介质中，或者从一个计算机可读存储介质向另一个计算机可读存储介质传输，例如，所述计算机指令可以从一个网站站点、计算机、服务器或数据中心通过有线(例如同轴电缆、光纤、数字用户线(digital subscriber line，DSL)或无线(例如红外、无线、微波等)方式向另一个网站站点、计算机、服务器或数据中心进行传输。所述计算机可读存储介质可以是计算机能够存取的任何可用介质或者是包含一个或多个可用介质集成的服务器、数据中心等数据存储设备。所述可用介质可以是磁性介质，(例如，软盘、硬盘、磁带)、光介质(例如，DVD)、或者半导体介质(例如固态硬盘(solid state disk，SSD))等。
本领域普通技术人员可以意识到，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，能够以电子硬件、或者计算机软件和电子硬件的结合来实现。这些功能究竟以硬件还是软件方式来执行，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来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申请的范围。
所属领域的技术人员可以清楚地了解到，为描述的方便和简洁，上述描述的系统、装置和单元的具体工作过程，可以参考前述方法实施例中的对应过程，在此不再赘述。
在本申请所提供的几个实施例中，应该理解到，所揭露的系统、装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，所述单元的划分，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，例如多个单元或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。
所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例方案的目的。
另外，在本申请各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。
所述功能如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读取存储介质中。基于这样的理解，本申请的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)执行本申请各个实施例所述方法的全部或部分步骤。而前述的存储介质包括：U盘、移动硬盘、只读存储器(Read-Only Memory，ROM)、随机存取存储器(Random Access Memory，RAM)、磁碟或者光盘等各种可以存储程序代码的介质。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (51)

  1. 一种通信方法，其特征在于，包括：
    网络设备根据终端在第一网络建立的协议数据单元PDU会话的切换指示信息，在所述建立的PDU会话中确定目标PDU会话，其中所述建立的PDU会话中每个PDU会话具有相同的数据网络名称DNN；
    所述网络设备向第二网络的移动性管理实体设备发送所述目标PDU会话的会话信息。
  2. 根据权利要求1所述的方法，其特征在于，所述切换指示信息用于指示所述建立的PDU会话中每个PDU会话的切换优先级，
    其中，在所述建立的PDU会话中确定目标PDU会话，包括：
    所述网络设备将所述建立的PDU会话中切换优先级最高的PDU会话确定为所述目标PDU会话。
  3. 根据权利要求1所述的方法，其特征在于，所述切换指示信息用于指示所述建立的PDU会话中每个PDU会话是否能够切换；
    其中，在所述建立的PDU会话中确定目标PDU会话，包括：
    在所述切换指示信息指示的能够切换的PDU会话只有一个的情况下，则所述网络设备确定该能够切换的PDU会话为所述目标PDU会话；或者，
    在所述切换指示信息指示能够切换的PDU会话至少有两个的情况下，则所述网络设备在该至少两个PDU会话中确定所述目标PDU会话。
  4. 根据权利要求3所述的方法，其特征在于，在所述切换指示信息指示的能够切换的PDU会话至少有两个的情况下，则所述网络设备在该至少两个PDU会话中确定所述目标PDU会话，包括：
    若所述至少两个PDU会话属于同一个控制面功能网元，则所述网络设备将该至少两个会话确定为所述目标会话；
    若所述至少两个PDU会话属于不同的控制面功能网元，则所述网络设备根据该至少两个PDU会话的该至少两个PDU会话中每个PDU会话的辅助信息，在该至少两个PDU会话中确定目标PDU会话。
  5. 根据权利要求1至4中任一项所述的方法，其特征在于，在所述网络设备根据终端在第一网络中建立的协议数据单元PDU会话的切换指示信息，在所述建立的PDU会话中确定目标PDU会话之前，所述方法还包括：
    所述网络设备接收来自第一控制面功能网元发送的所述建立的PDU会话中第一PDU会话的辅助信息；
    所述网络设备根据所述辅助信息确定所述第一PDU会话的切换指示信息。
  6. 根据权利要求4或5所述的方法，其特征在于，所述辅助信息包括以下至少一项：
    PDU会话对应的互联网协议IP地址版本、PDU会话对应的单网络切片辅助信息、PDU会话对应的会话和服务连续性SSC模式、PDU会话对应的分配和保留切换优先级ARP、PDU会话的对应的业务类型和PDU会话对应的建立时间。
  7. 根据权利要求1至4中任一项所述的方法，其特征在于，在所述网络设备根据终端在第一网络中建立的协议数据单元PDU会话的切换指示信息，在所述建立的PDU会话中 确定目标PDU会话之前，所述方法包括：
    所述网络设备接收来自至少一个控制面功能网元发送的终端在第一网络建立的PDU会话的切换指示信息。
  8. 根据权利要求1至4中任一项所述的方法，其特征在于，所述网络设备为用户数据管理网元，在所述网络设备根据终端在第一网络中建立的协议数据单元PDU会话的切换指示信息，在所述建立的PDU会话中确定目标PDU会话之前，所述方法包括：
    所述用户数据管理网元接收来自第二控制面功能网元发送的终端在第一网络建立的PDU会话中的第二PDU会话的初始切换指示信息；
    所述用户数据管理网元调整所述初始切换指示信息得到所述第二PDU会话的切换指示信息；
    所述方法还包括：
    所述用户数据管理网元向所述第二控制面功能网元发送所述第二PDU会话的切换指示信息。
  9. 根据权利要求1至8中任一项所述的方法，其特征在于，所述目标PDU会话的会话信息包括所述目标PDU会话对应的控制面功能网元的标识以及所述目标PDU会话的DNN。
  10. 一种通信方法，其特征在于，包括：
    终端获取在第一网络中建立的协议数据单元PDU会话的切换指示信息，所述建立的PDU会话中每个PDU会话具有相同的数据网络名称DNN；
    所述终端根据所述建立的PDU会话的切换指示信息，在所述建立的PDU会话中确定目标PDU会话；
    所述终端经由第二网络的移动性管理实体设备向第一控制面功能网元发送所述目标PDU会话的标识。
  11. 根据权利要求10所述的方法，其特征在于，所述切换指示信息用于指示所述建立的PDU会话中每个PDU会话的切换优先级，
    其中，在所述建立的PDU会话中确定目标PDU会话，包括：
    所述终端将所述建立的PDU会话中切换优先级最高的PDU会话确定为所述目标PDU会话。
  12. 根据权利要求10所述的方法，其特征在于，所述切换指示信息用于指示所述建立的PDU会话中每个PDU会话是否能够切换；
    其中，在所述建立的PDU会话中确定目标PDU会话，包括：
    所述终端将所述建立的PDU会话中能够切换的PDU会话确定为所述目标PDU会话。
  13. 根据权利要求10至12中任一项所述的方法，其特征在于，所述终端经由第二网络的移动性管理实体设备向第一控制面功能网元发送所述目标PDU会话的标识，包括：
    所述终端向所述移动性管理实体设备发送所述目标PDU会话的标识以及所述目标PDU会话的DNN，所述目标PDU会话的DNN用于所述移动性管理实体设备确定所述第一控制面功能网元，以便于所述移动性管理实体设备向所述第一控制面功能网元发送所述目标PDU会话的标识。
  14. 根据权利要求13所述的方法，其特征在于，所述终端向所述移动性管理实体设备发送所述目标PDU会话的标识以及所述目标PDU会话的数据网络名称，包括：
    所述终端向所述移动性管理实体设备发送第一请求消息，所述第一请求消息中携带所述目标PDU会话的标识以及所述目标PDU会话的DNN，所述第一请求消息为附着请求消息或者会话建立请求消息。
  15. 根据权利要求10至14中任一项所述的方法，其特征在于，所述终端获取在第一网络中建立的PDU会话的切换指示信息，包括：
    所述终端接收来自至少一个控制面功能网元发送的所述建立的PDU会话的切换指示信息。
  16. 根据权利要求10至14中任一项所述的方法，其特征在于，所述终端获取在第一网络中建立的PDU会话的切换指示信息，包括：
    所述终端向第二控制面功能网元发送所述第一PDU会话的初始切换指示信息，所述初始切换指示信息用于确定所述第一PDU会话的切换指示信息；
    所述终端接收所述第二控制面功能网元发送的所述第一PDU会话的切换指示信息。
  17. 一种通信方法，其特征在于，包括：
    第一控制面功能网元接收终端发送的会话建立请求消息，所述会话建立请求消息用于请求建立第一协议数据单元PDU会话；
    所述第一控制面功能网元获取所述第一PDU会话的切换指示信息。
  18. 根据权利要求17所述的方法，其特征在于，所述切换指示信息用于指示所述第一PDU会话的优先级或者用于指示所述第一PDU会话是否能够切换。
  19. 根据权利要求17或18所述的方法，其特征在于，所述会话建立请求消息包括所述第一PDU会话的切换指示信息，
    其中，所述第一控制面功能网元获取所述第一PDU会话的切换指示信息，包括：
    所述第一控制面功能网元在所述会话建立请求消息中获取所述第一PDU会话的切换指示信息；
    所述方法还包括：
    所述第一控制面功能网元向用户数据管理网元或接入和移动性管理功能设备发送所述第一PDU会话的切换指示信息。
  20. 根据权利要求17或18所述的方法，其特征在于，所述第一控制面功能网元获取所述第一PDU会话的切换的切换指示信息，包括：
    所述第一控制面功能网元获取所述第一PDU会话的初始切换指示信息；
    所述第一控制面功能网元获取根据所述初始切换指示信息调整得到的所述第一PDU会话的切换指示信息；
    所述方法还包括：
    所述第一控制面功能网元向所述终端或者用户数据管理网元或者接入和移动性管理功能设备发送所述第一PDU会话的切换指示信息。
  21. 根据权利要求17或18所述的方法，其特征在于，所述第一控制面功能网元获取所述第一PDU会话的切换的切换指示信息，包括：
    所述第一控制面功能网元向用户数据管理网元发送所述第一PDU会话的辅助信息；
    所述第一控制面功能网元接收所述用户数据管理网元发送的所述第一PDU会话的切换指示信息，所述第一PDU会话的切换指示信息根据所述第一PDU会话的辅助信息确定， 所述第一PDU会话的辅助信息包括所述第一PDU会话对应的互联网协议IP地址版本、所述第一PDU会话对应的单网络切片辅助信息、所述第一PDU会话对应的会话和服务连续性SSC模式、所述第一PDU会话对应的分配和保留切换优先级ARP、所述第一PDU会话的对应的业务类型和所述第一PDU会话对应的建立时间中的至少一项；
    所述方法还包括：
    所述第一控制面功能网元向所述终端或接入和移动性管理功能设备发送所述第一PDU会话的切换指示信息。
  22. 根据权利要求17至21中任一项所述的方法，其特征在于，所述方法还包括：
    所述第一控制面功能网元向用户数据管理网元发送所述第一PDU会话的数据网络名称DNN以及所述第一控制面功能网元的标识。
  23. 一种通信装置，其特征在于，包括：
    处理单元，用于根据终端在第一网络建立的协议数据单元PDU会话的切换指示信息，在所述建立的PDU会话中确定目标PDU会话，其中所述建立的PDU会话中每个PDU会话具有相同的数据网络名称DNN；
    收发单元，用于向第二网络的移动性管理实体设备发送所述目标PDU会话的会话信息。
  24. 根据权利要求23所述的装置，其特征在于，所述切换指示信息用于指示所述建立的PDU会话中每个PDU会话的切换优先级，
    所述处理单元具体用于：将所述建立的PDU会话中切换优先级最高的PDU会话确定为所述目标PDU会话。
  25. 根据权利要求23所述的装置，其特征在于，所述切换指示信息用于指示所述建立的PDU会话中每个PDU会话是否能够切换；
    所述处理单元具体用于：
    在所述切换指示信息指示的能够切换的PDU会话只有一个的情况下，确定该能够切换的PDU会话为所述目标PDU会话；或者
    在所述切换指示信息指示能够切换的PDU会话至少有两个的情况下，在该至少两个PDU会话中确定所述目标PDU会话。
  26. 根据权利要求25所述的装置，其特征在于，所述处理单元具体用于：
    若所述至少两个PDU会话属于同一个控制面功能网元，将该至少两个会话确定为所述目标会话；
    若所述至少两个PDU会话属于不同的控制面功能网元，根据该至少两个PDU会话的该至少两个PDU会话中每个PDU会话的辅助信息，在该至少两个PDU会话中确定目标PDU会话。
  27. 根据权利要求23至26中任一项所述的装置，其特征在于，所述收发单元还用于：
    在所述根据终端在第一网络中建立的协议数据单元PDU会话的切换指示信息，在所述建立的PDU会话中确定目标PDU会话之前，接收来自第一控制面功能网元发送的所述建立的PDU会话中第一PDU会话的辅助信息；
    所述处理单元还用于：根据所述辅助信息确定所述第一PDU会话的切换指示信息。
  28. 根据权利要求26或27所述的装置，其特征在于，所述辅助信息包括以下至少一 项：
    PDU会话对应的互联网协议IP地址版本、PDU会话对应的单网络切片辅助信息、PDU会话对应的会话和服务连续性SSC模式、PDU会话对应的分配和保留切换优先级ARP、PDU会话的对应的业务类型和PDU会话对应的建立时间。
  29. 根据权利要求23至26中任一项所述的装置，其特征在于，所述收发单元还用于：
    在所述根据终端在第一网络中建立的协议数据单元PDU会话的切换指示信息，在所述建立的PDU会话中确定目标PDU会话之前，接收来自至少一个控制面功能网元发送的终端在第一网络建立的PDU会话的切换指示信息。
  30. 根据权利要求23至26中任一项所述的装置，其特征在于，所述装置为用户数据管理网元，所述收发单元还用于：
    在所述根据终端在第一网络中建立的协议数据单元PDU会话的切换指示信息，在所述建立的PDU会话中确定目标PDU会话之前，接收来自第二控制面功能网元发送的终端在第一网络建立的PDU会话中的第二PDU会话的初始切换指示信息；
    所述处理单元还用于：调整所述初始切换指示信息得到所述第二PDU会话的切换指示信息；
    所述收发单元还用于：向所述第二控制面功能网元发送所述第二PDU会话的切换指示信息。
  31. 根据权利要求23至30中任一项所述的装置，其特征在于，所述目标PDU会话的会话信息包括所述目标PDU会话对应的控制面功能网元的标识以及所述目标PDU会话的DNN。
  32. 一种通信装置，其特征在于，包括：
    获取单元，用于获取在第一网络中建立的协议数据单元PDU会话的切换指示信息，所述建立的PDU会话中每个PDU会话具有相同的数据网络名称DNN；
    处理单元，用于根据所述建立的PDU会话的切换指示信息，在所述建立的PDU会话中确定目标PDU会话；
    收发单元，用于经由第二网络的移动性管理实体设备向第一控制面功能网元发送所述目标PDU会话的标识。
  33. 根据权利要求32所述的装置，其特征在于，所述切换指示信息用于指示所述建立的PDU会话中每个PDU会话的切换优先级，
    所述处理单元具体用于：将所述建立的PDU会话中切换优先级最高的PDU会话确定为所述目标PDU会话。
  34. 根据权利要求32所述的装置，其特征在于，所述切换指示信息用于指示所述建立的PDU会话中每个PDU会话是否能够切换；
    所述处理单元具体用于：将所述建立的PDU会话中能够切换的PDU会话确定为所述目标PDU会话。
  35. 根据权利要求32至34中任一项所述的装置，其特征在于，所述收发单元具体用于：
    向所述移动性管理实体设备发送所述目标PDU会话的标识以及所述目标PDU会话的DNN，所述目标PDU会话的DNN用于所述移动性管理实体设备确定所述第一控制面功能网 元，以便于所述移动性管理实体设备向所述第一控制面功能网元发送所述目标PDU会话的标识。
  36. 根据权利要求35所述的装置，其特征在于，所述收发单元具体用于：
    向所述移动性管理实体设备发送第一请求消息，所述第一请求消息中携带所述目标PDU会话的标识以及所述目标PDU会话的DNN，所述第一请求消息为附着请求消息或者会话建立请求消息。
  37. 根据权利要求32至36中任一项所述的装置，其特征在于，所述获取单元具体用于：
    接收来自至少一个控制面功能网元发送的所述建立的PDU会话的切换指示信息。
  38. 根据权利要求32至36中任一项所述的装置，其特征在于，所述收发单元还用于：
    向第二控制面功能网元发送所述第一PDU会话的初始切换指示信息，所述初始切换指示信息用于确定所述第一PDU会话的切换指示信息；
    接收所述第二控制面功能网元发送的所述第一PDU会话的切换指示信息。
  39. 一种通信装置，其特征在于，包括：
    收发单元，用于接收终端发送的会话建立请求消息，所述会话建立请求消息用于请求建立第一协议数据单元PDU会话；
    获取单元，用于获取所述第一PDU会话的切换指示信息。
  40. 根据权利要求39所述的装置，其特征在于，所述切换指示信息用于指示所述第一PDU会话的优先级或者用于指示所述第一PDU会话是否能够切换。
  41. 根据权利要求39或40所述的装置，其特征在于，所述会话建立请求消息包括所述第一PDU会话的切换指示信息，
    所述获取单元具体用于：在所述会话建立请求消息中获取所述第一PDU会话的切换指示信息；
    所述收发单元还用于：向用户数据管理网元或接入和移动性管理功能设备发送所述第一PDU会话的切换指示信息。
  42. 根据权利要求39或40所述的装置，其特征在于，所述获取单元具体用于：
    获取所述第一PDU会话的初始切换指示信息；
    所述装置还包括：
    处理单元，用于获取根据所述初始切换指示信息调整得到的所述第一PDU会话的切换指示信息；
    收发单元还用于：向所述终端或者用户数据管理网元或者接入和移动性管理功能设备发送所述第一PDU会话的切换指示信息。
  43. 根据权利要求39或40所述的装置，其特征在于，所述收发单元还用于：
    向用户数据管理网元发送所述第一PDU会话的辅助信息；
    接收所述用户数据管理网元发送的所述第一PDU会话的切换指示信息，所述第一PDU会话的切换指示信息根据所述第一PDU会话的辅助信息确定，所述第一PDU会话的辅助信息包括所述第一PDU会话对应的互联网协议IP地址版本、所述第一PDU会话对应的单网络切片辅助信息、所述第一PDU会话对应的会话和服务连续性SSC模式、所述第一PDU会话对应的分配和保留切换优先级ARP、所述第一PDU会话的对应业务类型和所述第一PDU 会话对应的建立时间中的至少一项；
    向所述终端或接入和移动性管理功能设备发送所述第一PDU会话的切换指示信息。
  44. 根据权利要求39至43中任一项所述的装置，其特征在于，所述收发单元还用于：
    向用户数据管理网元发送所述第一PDU会话的数据网络名称DNN以及所述装置的标识。
  45. 一种计算机存储介质，所述计算机可读存储介质中存储有指令，当其在计算机上运行时，使得计算机执行所述权利要求1-9中任意一项所述的方法。
  46. 一种计算机存储介质，所述计算机可读存储介质中存储有指令，当其在计算机上运行时，使得计算机执行所述权利要求10-16中任意一项所述的方法。
  47. 一种计算机存储介质，所述计算机可读存储介质中存储有指令，当其在计算机上运行时，使得计算机执行所述权利要求17-22中任意一项所述的方法。
  48. 一种装置，其特征在于，所述装置包括处理器和存储器；
    所述存储器用于存储计算机执行指令，当所述装置运行时，所述处理器执行所述存储器存储的所述计算机执行指令，以使所述装置执行如权利要求1-9中任意一项所述的方法。
  49. 一种装置，其特征在于，所述装置包括处理器和存储器；
    所述存储器用于存储计算机执行指令，当所述装置运行时，所述处理器执行所述存储器存储的所述计算机执行指令，以使所述装置执行如权利要求10-16中任意一项所述的方法。
  50. 根据权利要求49所述的装置，其特征在于，所述装置包括终端或所述终端内的芯片。
  51. 一种装置，其特征在于，所述装置包括处理器和存储器；
    所述存储器用于存储计算机执行指令，当所述装置运行时，所述处理器执行所述存储器存储的所述计算机执行指令，以使所述装置执行如权利要求17-22中任意一项所述的方法。
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