WO2022033526A1 - 一种通信方法及装置 - Google Patents

一种通信方法及装置 Download PDF

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Publication number
WO2022033526A1
WO2022033526A1 PCT/CN2021/112097 CN2021112097W WO2022033526A1 WO 2022033526 A1 WO2022033526 A1 WO 2022033526A1 CN 2021112097 W CN2021112097 W CN 2021112097W WO 2022033526 A1 WO2022033526 A1 WO 2022033526A1
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Prior art keywords
network
pdu session
terminal device
information
message
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PCT/CN2021/112097
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English (en)
French (fr)
Inventor
朱强华
吴问付
Original Assignee
华为技术有限公司
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Priority claimed from CN202011066441.3A external-priority patent/CN114079990A/zh
Application filed by 华为技术有限公司 filed Critical 华为技术有限公司
Publication of WO2022033526A1 publication Critical patent/WO2022033526A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements

Definitions

  • the present application relates to the field of mobile communication technologies, and in particular, to a communication method and device.
  • NPN non-public network
  • PLMN public land mobile network
  • SNPN standalone NPN
  • the interworking between the PLMN and the SNPN can be realized through a non-3rd generation partnership project (non-3GPP) interworking function (interworking function, N3IWF).
  • non-3GPP non-3rd generation partnership project
  • N3IWF networking function
  • the interworking between the PLMN and the SNPN can be implemented through the roaming architecture shown in FIG. 2 .
  • the two methods also support intercommunication between SNPNs and SNPNs.
  • the present application provides a communication method and apparatus to solve the problem of low switching efficiency or inability to correctly switch between UEs across NPN networks.
  • an embodiment of the present application provides a communication method, and the method can be implemented by a terminal device or a component of the terminal device (such as a chip, a circuit, and other components).
  • the terminal device may be a UE.
  • the terminal device registered in the first network can be associated with a data network name (DNN) and a single network slice selection auxiliary information (single network slice) in the first network.
  • DNN data network name
  • S-NSSAI network slice selection assistance information
  • PDU protocol data unit
  • the terminal device may also send a first registration request message to the first network device.
  • the first message is used for requesting to register with the second network.
  • the following description takes the first message as the first registration request message as an example, but it should not be understood that the first message is limited to the registration request.
  • the terminal device may also receive first information from the first network device, where the first information is determined according to an intercommunication manner between the first network and the second network.
  • the terminal device may further establish a PDU session of the terminal device according to the first information, where the PDU session is associated with the DNN and the S-NSSAI.
  • the UE after registering from the first network to the second network, the UE can receive the first information from the first network device in the second network, since the first information and the relationship between the first network and the second network
  • the interworking mode is related, and the PDU session associated with the DNN and the S-NSSAI of the UE can be recovered more efficiently according to the first information, so as to improve the handover efficiency and ensure service continuity.
  • the first registration request message may include a cross-non-public network handover indication, which is used to instruct the terminal device to perform cross-non-public network handover.
  • the above interworking manner between the first network and the second network includes non-interworking between the first network and the second network, interworking between the first network and the second network based on N3IWF, or all Roaming-based interworking between the first network and the second network.
  • the terminal device may send a second message to the first network device, where the second message includes a value as an initial request (initial request) request type (request type) information element, or in other words, the second message is used to request the establishment of the initial PDU session.
  • the following description takes the second message as the first PDU session request message as an example, but it should not be understood that the second message is limited to the PDU session request message.
  • the first PDU session request message may include information of the DNN and information of the S-NSSAI to request establishment of a PDU session associated with the DNN and the S-NSSAI.
  • the UE can create a new PDU session associated with the DNN and the S-NSSAI in the second network to restore the PDU session associated with the DNN and the S-NSSAI, Improve switching efficiency.
  • the first information is used to indicate that the first network and the second network are not interoperable, or, The first information is used to instruct the terminal device to send the first PDU session request to the first network device. Accordingly, a flexible indication of the interworking manner can be realized.
  • the terminal device may send a third message to the first network device, where the third message is used to request the establishment of the first network Two PDU sessions.
  • the following description takes the third message as the second PDU session request message as an example, but it should not be understood that the third message is limited to the PDU session request message.
  • the terminal device can also establish a connection with the N3IWF through the second PDU session, and the N3IWF belongs to the first network.
  • the terminal device may also send a fourth message to the second network device through the connection, where the fourth message is used to request to register with the first network in the N3GPP manner, and the second network device belongs to the first network.
  • the terminal device may also send a fifth message to the second network device, where the fifth message includes a request type information element whose value is an existing PDU session (existing PDU session), or in other words, the fifth message is used to request the establishment of an existing PDU session .
  • the following description takes the fifth message as the third PDU session request message as an example, but it should not be understood that the fifth message is limited to the PDU session request message.
  • the third PDU session request message may carry the information of the DNN and the information of the S-NSSAI.
  • the UE can establish the information associated with the DNN and the third PDU session of the S-NSSAI through the N3IWF and the second network device, so as to realize the association of the UE to the
  • the recovery of the PDU session of the DNN and the S-NSSAI improves the handover efficiency.
  • the first information may be used to indicate N3IWF-based interworking between the first network and the second network, or Used to instruct the terminal device to send the second PDU session request to the first network device, to send the second registration request to the second network device through the N3IWF, and to send the third PDU session request message to the second network device .
  • the terminal device may send a sixth message to the first network device, where the sixth message includes a value of The request type information element of the existing PDU session, the information of the DNN and the information of the S-NSSAI.
  • the sixth message includes a value of The request type information element of the existing PDU session, the information of the DNN and the information of the S-NSSAI.
  • the UE can establish the information associated with the DNN and the fourth PDU session of the S-NSSAI through the first network device, so as to realize the association of the UE with the DNN and the S-NSSAI.
  • the recovery of the PDU session of S-NSSAI improves the handover efficiency.
  • the first information may be used to indicate roaming-based interworking between the first network and the second network, or It is used to instruct the terminal device to send the fourth PDU session request message to the first network device.
  • the fourth PDU session request message includes a lossless handover indication. Therefore, in the case where the interworking manner includes roaming-based interworking between the first network and the second network, lossless network handover of the UE can be supported.
  • an embodiment of the present application provides a communication method, and the method can be executed by a first network device or a component thereof.
  • the first network equipment may include a core network access and mobility management function (core access and mobility management function, AMF).
  • AMF core access and mobility management function
  • the first network device can receive the first registration request message from the terminal device, the first network device belongs to the second network, and the first registration request message is used for Request to register with the second network.
  • the first network device may also acquire the context of the terminal device, and determine according to the context that the terminal device has been registered with the first network.
  • the first network device may also send the first information to the terminal device according to the communication mode between the first network and the second network.
  • the first network device may determine that the terminal device performs cross-non-public network handover according to the cross-non-public network handover indication included in the first registration request message, and the cross-non-public network handover indication is used to indicate the The terminal device performs cross-non-public network handover.
  • the first network device may determine that the terminal device performs cross-non-public network handover according to the identifier of the first network, and the identifier of the first network is included in the context.
  • the first network device may determine that the terminal device performs cross-non-public network handover according to the identifier of the second network device, and the identifier of the second network device is included in the context of the terminal device.
  • the second network device is a network device that the terminal device accesses when it registers with the first network, such as an AMF.
  • the first network device may receive the context of the terminal device from the second network device deployed in the first network.
  • the first network device may acquire the information of the second network device from unified data management (unified data management, UDM), and request the context of the terminal device.
  • unified data management unified data management, UDM
  • the first network device receives the context of the terminal device from the data storage node, and the data storage node is shared by the first network and the second network.
  • the data storage node includes a UDM or authentication, authorization, accounting (authentication, authorization, accounting, AAA) server.
  • the above interworking manner between the first network and the second network includes non-interworking between the first network and the second network, interworking between the first network and the second network based on N3IWF, or all Roaming-based interworking between the first network and the second network.
  • the first information may be used to indicate that the first network and the second network are not interoperable, or the first information It can be used to instruct the terminal device to send the first PDU session request message to the first network device.
  • the first PDU session request message includes a request type information element whose value is initial request, or in other words, the first PDU session request message is used to request the establishment of an initial PDU session.
  • the first PDU session request message also includes the DNN (or DNN information) associated with the PDU session established by the terminal device on the first network and the S-NSSAI (or S-NSSAI information) associated with the PDU session, or , the first information is further used to instruct the UE to carry the information of the DNN associated with the PDU session established by the terminal device in the first network and the information of the S-NSSAI associated with the PDU session in the first PDU session request message.
  • the first information may be used to indicate N3IWF-based interworking between the first network and the second network.
  • the first information may be used to instruct the terminal device to send a second PDU session request message to the first network device, to send a second registration request message to the second network device through the N3IWF, and to send a third PDU session to the second network device request message.
  • the second PDU session request message is used to request the establishment of a second PDU session, and the second PDU session is used to establish a connection between the terminal device and the N3IWF; the second registration request message is used to request the The N3GPP method is registered in the first network; the third PDU session request message includes a request type information element whose value is the existing PDU session, and the information of the DNN associated with the PDU session established by the terminal device in the first network. and the information of the S-NSSAI associated with the PDU session.
  • the first information may indicate roaming-based interworking between the first network and the second network.
  • the first information may instruct the terminal device to send a fourth PDU session request message to the first network device, where the fourth PDU session request message includes a request type information element whose value is the existing PDU session, or in other words, the fourth PDU session request message Used to request the establishment of an existing PDU session.
  • the fourth PDU session request message also includes the information of the DNN associated with the PDU session established by the terminal device on the first network and the information of the S-NSSAI associated with the PDU session.
  • the first information is also used to indicate the terminal device
  • the fourth PDU session request message carries the information of the DNN associated with the PDU session established by the terminal device on the first network and the information of the S-NSSAI associated with the PDU session.
  • the first network device may also receive the above-mentioned fourth PDU session request message from the terminal device.
  • the first network device may also send the fourth PDU session request message to the first SMF, where the first SMF is an intermediate SMF, the first SMF is connected to the second SMF, and the second SMF maintains the terminal device in the first network
  • the first SMF can then forward the fourth PDU session request message to the second SMF, and the second SMF performs path switching.
  • the first SMF belongs to the first network, and the first SMF maintains the first PDU session established by the terminal device in the first network and associated with the DNN and the S-NSSAI.
  • the first network device may also send a cross-non-public network handover instruction to the first SMF, where the cross-non-public network handover instruction is used to instruct the terminal device to perform cross-non-public network handover.
  • the fourth PDU session request includes a lossless handover indication.
  • an embodiment of the present application provides a communication method, and the method can be implemented by a terminal device or a component of the terminal device (such as a chip, a circuit, and other components).
  • the terminal device may be a UE.
  • the terminal device registered in the first network can establish a first PDU session associated with the DNN and S-NSSAI in the first network, and the terminal device can also report to the first network.
  • the network device sends a first registration request message, where the first registration request message is used to request registration to the second network.
  • the terminal device establishes (or requests to establish) a PDU session of the terminal device according to the first sequence, the PDU session is associated with the DNN and the S-NSSAI associated with the first PDU session, and the PDU session is associated with the first PDU session. DNN and S-NSSAI are associated.
  • the first sequence is used to instruct the terminal device to establish the sequence of the PDU session of the terminal device according to the sequence of the third mode, the second mode and the first mode.
  • the terminal device attempts to establish the PDU session of the terminal device according to the third manner, the second manner and the first manner in the first order until the PDU session is established.
  • the first information may indicate the respective priorities of the first mode, the second mode, and the third mode, wherein the third mode has the highest priority, and the second mode has a higher priority than the first mode.
  • the third mode, the second mode and the first mode may be executed in sequence according to the priority, wherein if the PDU session is successfully established in a certain mode, the terminal device will no longer attempt to establish the PDU session according to the lower priority.
  • the successful establishment of the PDU session here refers to receiving a PDU session establishment response message from the network side, and the PDU session establishment response message indicates the successful establishment of the PDU session.
  • the terminal device can restore the PDU session through the first method, the second method and/or the third method in the first order to improve handover efficiency.
  • the first registration request message includes a cross-non-public network handover indication, where the cross-non-public network handover indication is used to instruct the terminal device to perform cross-non-public network handover.
  • the terminal device may send a first PDU session request message to the first network device, wherein the first PDU session request message includes a value
  • the request type information element of the initial request or in other words, the first PDU session request message is used to request the establishment of an initial PDU session.
  • the first PDU session request message includes the information of the DNN and the information of the S-NSSAI to request to establish a PDU session associated with the DNN and the S-NSSAI.
  • the terminal device may send a second PDU session request message to the first network device, where the second PDU session request is used to request to establish a second PDU session.
  • the terminal device can establish a connection with the N3IWF through the second PDU session, and the N3IWF belongs to the first network.
  • the terminal device sends a second registration request message to the second network device through the connection, where the second registration request message is used for requesting to register in the first network by means of N3GPP, and the second network device belongs to the first network.
  • the terminal device may send a third PDU session request message to the second network device, where the third PDU session request message includes a request type information element with a value of existing PDU session, or, in other words, the The third PDU session request message may be used to request the establishment of an existing PDU session.
  • the third PDU session request message may include the information of the DNN and the information of the S-NSSAI.
  • the terminal device may send a fourth PDU session request message to the first network device, where the fourth PDU session request message includes a value of existing PDU session
  • the request type information element or in other words, the fourth PDU session request message may be used to request the establishment of an existing PDU session.
  • the fourth PDU session request message further includes the information of the DNN and the information of the S-NSSAI. Therefore, the terminal device can preferentially establish a PDU session associated with the DNN and the S-NSSAI through the fourth PDU session request message, thereby improving handover efficiency.
  • the fourth PDU session request message includes a lossless handover indication to support lossless handover.
  • the first order is determined according to a local configuration.
  • the terminal device may receive the first sequence of indication information from the first network device.
  • the indication information of the first order may be determined according to the local configuration of the first network device, or determined by the first network device according to an intercommunication manner between the first network and the second network.
  • the terminal device may receive the first sequence of indication information from the second network device.
  • the indication information of the first order may be determined according to the local configuration of the second network device, or determined by the second network device according to the intercommunication mode between the first network and the second network. Therefore, the first order can be determined flexibly.
  • the first registration request message includes a cross-non-public network handover indication, where the cross-non-public network handover indication is used to instruct the terminal device to perform cross-non-public network handover.
  • an embodiment of the present application provides a communication method, and the method can be executed by a session management function (session management function, SMF) or a component thereof.
  • SMF session management function
  • the SMF can establish a first PDU session associated with the DNN and the S-NSSAI of the terminal device, and the terminal device is registered in the first network.
  • the first PDU session is a PDU session between a first access network element and a first UPF, and the first access network element belongs to the first network.
  • the SMF may receive a fourth PDU session request message, where the fourth PDU session request message includes a request type information element whose value is the existing PDU session, or in other words, the fourth PDU session request message may be used to request the establishment of an existing PDU session.
  • the fourth PDU session request message further includes the information of the DNN and the information of the S-NSSAI to request to establish a PDU session associated with the DNN and the S-NSSAI.
  • the SMF may also send second information to the first UPF, where the second information is used to instruct the first UPF to send an end marker to the first access network element after the path switching of the first PDU session, and the second information is used to indicate the
  • the first UPF forwards the downlink data from the terminal device of the first access network element to the terminal device through the switched path, where the downlink data includes the end marker.
  • the SMF may also send third information to the first access network element, where the third information is used to instruct the first access network element to forward the downlink data of the terminal device buffered by the first access network element to the first access network element.
  • the first UPF until the end marker is received and forwarded.
  • the SMF can support lossless path switching of the terminal device to maintain service continuity.
  • the fourth PDU session request message includes a lossless handover indication, or the SMF may determine to perform a lossless handover for the terminal device according to a local configuration.
  • the SMF may also receive a non-public network handover indication.
  • the above fourth PDU request message comes from a first network device, and the first network device belongs to the second network.
  • the SMF is connected to the second network, and the first network device is connected to the SMF.
  • the fourth PDU session request message is sent by the first network device to the intermediate SMF, and forwarded by the intermediate SMF to the SMF.
  • the SMF does not belong to the second network, and the first network device is not directly connected to the SMF.
  • the intermediate SMF performs message forwarding.
  • an embodiment of the present application provides a communication apparatus, which can implement the method in the first aspect or any possible implementation manner of the first aspect.
  • the apparatus comprises corresponding units or components for carrying out the above-described method.
  • the units included in the apparatus may be implemented by software and/or hardware.
  • the apparatus may be, for example, a terminal device, or a chip, a chip system, or a processor that can support the terminal device to implement the above method.
  • the structure of the communication apparatus may include a communication module, a processing module, etc., and these modules may perform the corresponding functions of the terminal device in the first aspect or each possible design example of the first aspect.
  • the communication module can be used for the communication device to perform reception and transmission of signals, data, information or messages
  • the processing module can be used to process the signals, data, information or messages received by the communication module, or to generate a signal sent by the communication module. Signal, data, information or message.
  • the communication device may be registered with the first network, the communication module may establish a first PDU session associated with the DNN and the S-NSSAI in the first network, and the communication module may also report to the first network.
  • a network device sends a first registration request message, where the first registration request message is used to request registration to the second network.
  • the communication module may also receive first information from the first network device, where the first information is determined according to an intercommunication manner between the first network and the second network.
  • the communication module may further establish a PDU session according to the first information, and the PDU session is associated with the DNN and the S-NSSAI.
  • the first registration request message may include a cross-non-public network handover indication, which is used to instruct the communication device to perform cross-non-public network handover.
  • the above interworking manner between the first network and the second network includes non-interworking between the first network and the second network, interworking between the first network and the second network based on N3IWF, or all Roaming-based interworking between the first network and the second network.
  • the communication module may send a first PDU session request message to the first network device, and the first PDU session
  • the request message includes a request type information element whose value is initial request, or in other words, the first PDU session request message is used to request the establishment of an initial PDU session.
  • the first PDU session request message includes the information of the DNN and the information of the S-NSSAI to request to establish a PDU session associated with the DNN and the S-NSSAI.
  • the UE can create a new PDU session associated with the DNN and the S-NSSAI in the second network to restore the PDU session associated with the DNN and the S-NSSAI, Improve switching efficiency.
  • the first information is used to indicate that the first network and the second network are not interoperable, or, The first information is used to instruct the communication apparatus to send the first PDU session request to the first network device. Accordingly, a flexible indication of the interworking manner can be realized.
  • the communication module may send a second PDU session request message to the first network device, the second PDU session The request is used to request the establishment of a second PDU session.
  • the communication module may also establish a connection with the N3IWF through the second PDU session, the N3IWF belonging to the first network.
  • the communication module can also send a second registration request message to the second network device through the connection, where the second registration request message is used to request to register in the first network by means of N3GPP, and the second network device belongs to the first network.
  • the communication module may also send a third PDU session request message to the second network device, where the third PDU session request message includes a request type information element whose value is the existing PDU session, or in other words, the third PDU session request message is used to request establishment There is already a PDU session.
  • the third PDU session request message may carry the information of the DNN and the information of the S-NSSAI.
  • the UE can establish the information associated with the DNN and the third PDU session of the S-NSSAI through the N3IWF and the second network device, so as to realize the association of the UE to the
  • the recovery of the PDU session of the DNN and the S-NSSAI improves the handover efficiency.
  • the first information may be used to indicate N3IWF-based interworking between the first network and the second network, or It is used for instructing to send the second PDU session request to the first network device, to send the second registration request to the second network device through the N3IWF, and to send the third PDU session request message to the second network device.
  • the communication module may send a fourth PDU session request message to the first network device, the fourth PDU
  • the session request message includes a request type cell whose value is the existing PDU session, the information of the DNN, and the information of the S-NSSAI. Therefore, in the roaming-based intercommunication between the first network and the second network, the UE can establish the information associated with the DNN and the fourth PDU session of the S-NSSAI through the first network device, so as to realize the association of the UE with the DNN and the S-NSSAI. The recovery of the PDU session of S-NSSAI improves the handover efficiency.
  • the first information may be used to indicate roaming-based interworking between the first network and the second network, or It is used for instructing to send the fourth PDU session request message to the first network device.
  • the fourth PDU session request message includes a lossless handover indication. Therefore, in the case where the interworking manner includes roaming-based interworking between the first network and the second network, lossless network handover of the UE can be supported.
  • the structure of the communication device may include a processor, and optionally a communication interface (eg, a transceiver) and a memory.
  • the communication interface can be used for sending and receiving information or data, and for the communication device to communicate and interact with other communication devices (eg, the first network device) in the network system.
  • the processor is configured to support the communication apparatus to perform corresponding functions of the terminal device in the first aspect or each possible design example of the first aspect.
  • the memory is coupled to the processor for storing necessary program instructions and data for the communication device.
  • the transceiver may be configured to perform the steps performed by the communication module described in the fifth aspect
  • the processor may be configured to perform the steps performed by the processing module described in the fifth aspect.
  • an embodiment of the present application provides a communication device, which can implement the method in the second aspect or any possible implementation manner of the second aspect.
  • the apparatus comprises corresponding units or components for carrying out the above-described method.
  • the units included in the apparatus may be implemented by software and/or hardware.
  • the apparatus may be, for example, a first network device, or a chip, a chip system, or a processor that can support the first network device to implement the second aspect or any possible method of the second aspect.
  • the structure of the communication apparatus may include a communication module, a processing module, etc., and these modules may perform the corresponding functions of the first network device in the second aspect or each possible design example of the second aspect .
  • the communication module can be used for the communication device to perform reception and transmission of signals, data, information or messages
  • the processing module can be used to process the signals, data, information or messages received by the communication module, or to generate a signal sent by the communication module. Signal, data, information or message.
  • the communication module may receive a first registration request message from the terminal device, the communication device belongs to the second network, and the first registration request message is used to request registration to the second network .
  • the processing module may acquire the context of the terminal device, and determine that the terminal device has been registered with the first network according to the context.
  • the communication module may also send the first information to the terminal device according to the communication mode between the first network and the second network.
  • the processing module may further determine that the terminal device performs cross-non-public network handover according to the cross-non-public network handover indication included in the first registration request message, and the cross-non-public network handover indication is used to indicate the The terminal device performs cross-non-public network handover.
  • the processing module may determine that the terminal device performs cross-non-public network handover according to the identifier of the first network, and the identifier of the first network is included in the context.
  • the processing module may determine that the terminal device performs cross-non-public network handover according to the identifier of the second network device, and the identifier of the second network device is included in the context of the terminal device.
  • the second network device is a network device that the terminal device accesses when it registers with the first network, such as an AMF.
  • the communication module may receive the context of the terminal device from the second network device deployed in the first network.
  • the communication module can obtain the information of the second network device from the UDM, and request the context of the terminal device.
  • the communication module may receive the context of the terminal device from the data storage node, and the data storage node is shared by the first network and the second network.
  • the data storage node includes a UDM or AAA server.
  • the above interworking manner between the first network and the second network includes non-interworking between the first network and the second network, interworking between the first network and the second network based on N3IWF, or all Roaming-based interworking between the first network and the second network.
  • the first information may be used to indicate that the first network and the second network are not interoperable, or the first information It can be used to instruct the terminal device to send the first PDU session request message to the communication apparatus.
  • the first PDU session request message includes a request type information element whose value is initial request, or in other words, the first PDU session request message is used to request the establishment of an initial PDU session.
  • the first PDU session request message also includes the DNN (or DNN information) associated with the PDU session established by the terminal device on the first network and the S-NSSAI (or S-NSSAI information) associated with the PDU session, or , the first information is further used to instruct the UE to carry the information of the DNN associated with the PDU session established by the terminal device in the first network and the information of the S-NSSAI associated with the PDU session in the first PDU session request message.
  • the first information may be used to indicate N3IWF-based interworking between the first network and the second network.
  • the first information may be used to instruct the terminal device to send a second PDU session request message to the communication apparatus, to send a second registration request message to the second network device through the N3IWF, and to send a third PDU session request to the second network device information.
  • the second PDU session request message is used to request the establishment of a second PDU session, and the second PDU session is used to establish a connection between the terminal device and the N3IWF; the second registration request message is used to request the The N3GPP method is registered in the first network; the third PDU session request message includes a request type information element whose value is the existing PDU session, and the information of the DNN associated with the PDU session established by the terminal device in the first network. and the information of the S-NSSAI associated with the PDU session.
  • the first information may indicate roaming-based interworking between the first network and the second network.
  • the first information may instruct the terminal device to send a fourth PDU session request message to the communication apparatus, where the fourth PDU session request message includes a request type information element whose value is the existing PDU session, or in other words, the fourth PDU session request message uses upon request to establish an existing PDU session.
  • the fourth PDU session request message also includes the information of the DNN associated with the PDU session established by the terminal device on the first network and the information of the S-NSSAI associated with the PDU session.
  • the first information is also used to indicate the terminal device
  • the fourth PDU session request message carries the information of the DNN associated with the PDU session established by the terminal device on the first network and the information of the S-NSSAI associated with the PDU session.
  • the communication module may further receive the above-mentioned fourth PDU session request message from the terminal device.
  • the communication module may also send the fourth PDU session request message to the first SMF, where the first SMF is an intermediate SMF, the first SMF is connected to the second SMF, and the second SMF maintains the connection established by the terminal device on the first network.
  • the first SMF can subsequently forward the fourth PDU session request message to the second SMF, and the second SMF performs path switching.
  • the first SMF belongs to the first network, and the first SMF maintains the first PDU session established by the terminal device in the first network and associated with the DNN and the S-NSSAI.
  • the communication module may further send a cross-non-public network handover instruction to the first SMF, where the cross-non-public network handover instruction is used to instruct the terminal device to perform cross-non-public network handover.
  • the fourth PDU session request includes a lossless handover indication.
  • the structure of the communication device may include a processor, and optionally a communication interface (eg, a wired communication interface, etc.) and a memory.
  • the communication interface can be used for sending and receiving information or data, and for the communication device to communicate and interact with other communication devices (such as terminal equipment, etc.) in the network system.
  • the processor is configured to support the communication apparatus to perform the corresponding functions of the first network device in the above-mentioned second aspect or each possible design example of the second aspect.
  • the memory is coupled to the processor for storing necessary program instructions and data for the communication device.
  • the transceiver may be configured to perform the steps performed by the communication module described in the sixth aspect
  • the processor may be configured to perform the steps performed by the processing module described in the sixth aspect.
  • an embodiment of the present application provides a communication apparatus, which can implement the method in the third aspect or any possible implementation manner of the third aspect.
  • the apparatus comprises corresponding units or components for carrying out the above-described method.
  • the units included in the apparatus may be implemented by software and/or hardware.
  • the apparatus may be, for example, a terminal device, or a chip, a chip system, or a processor that can support the terminal device to implement the above method.
  • the structure of the communication apparatus may include a communication module, a processing module, etc., and these modules may perform corresponding functions of the terminal device in the third aspect or each possible design example of the third aspect.
  • the communication module can be used for the communication device to perform reception and transmission of signals, data, information or messages
  • the processing module can be used to process the signals, data, information or messages received by the communication module, or to generate a signal sent by the communication module. Signal, data, information or message.
  • the communication device When performing the method shown in the third aspect, the communication device is registered with the first network, the communication module can establish a first PDU session associated with the DNN and the S-NSSAI in the first network, and the communication module can also report to the first network
  • the device sends a first registration request message, where the first registration request message is used to request registration to the second network.
  • the communication module establishes a PDU session associated with the DNN and the S-NSSAI according to the first order.
  • the first sequence is used to indicate that the PDU session is established according to the third mode, the second mode and the first mode successively.
  • the processing module establishes (or requests to establish) the PDU session in the third manner, the second manner and the first manner through the communication module in the first order, until the PDU session is established.
  • the first registration request message includes a cross-non-public network handover indication, where the cross-non-public network handover indication is used to instruct to perform cross-non-public network handover.
  • the communication module may send a first PDU session request message to the first network device, wherein the first PDU session request message includes a value of initial request The request type information element, or in other words, the first PDU session request message is used to request the establishment of an initial PDU session.
  • the first PDU session request message includes the information of the DNN and the information of the S-NSSAI to request to establish a PDU session associated with the DNN and the S-NSSAI.
  • the communication module may send a second PDU session request message to the first network device, where the second PDU session request is used to request to establish a second PDU session.
  • the communication module may establish a connection with the N3IWF through the second PDU session, the N3IWF belonging to the first network.
  • the communication module sends a second registration request message to the second network device through the connection, where the second registration request message is used for requesting to register in the first network by means of N3GPP, and the second network device belongs to the first network.
  • the communication module may send a third PDU session request message to the second network device, where the third PDU session request message includes a request type information element whose value is the existing PDU session, or, in other words, The third PDU session request message may be used to request the establishment of an existing PDU session.
  • the third PDU session request message may include the information of the DNN and the information of the S-NSSAI.
  • the communication module may send a fourth PDU session request message to the first network device, where the fourth PDU session request message includes a request whose value is existing PDU session
  • the type information element or in other words, the fourth PDU session request message may be used to request the establishment of an existing PDU session.
  • the fourth PDU session request message further includes the information of the DNN and the information of the S-NSSAI.
  • the fourth PDU session request message includes a lossless handover indication to support lossless handover.
  • the first order is determined according to a local configuration.
  • the communication module may receive the indication information of the first order from the first network device.
  • the indication information of the first order may be determined according to the local configuration of the first network device, or determined by the first network device according to an intercommunication manner between the first network and the second network.
  • the communication module may receive the first sequence of indication information from the second network device.
  • the indication information of the first order may be determined according to the local configuration of the second network device, or determined by the second network device according to the intercommunication mode between the first network and the second network. Therefore, the first order can be determined flexibly.
  • the structure of the communication device may include a processor, and optionally a communication interface and a memory.
  • the communication interface can be used for sending and receiving information or data, and for the communication device to communicate and interact with other communication devices (eg, the first network device) in the network system.
  • the processor is configured to support the communication apparatus to perform the corresponding functions of the terminal device in the third aspect or each possible design example of the third aspect.
  • the memory is coupled to the processor for storing necessary program instructions and data for the communication device.
  • the transceiver may be configured to perform the steps performed by the communication module described in the seventh aspect
  • the processor may be configured to perform the steps performed by the processing module described in the seventh aspect.
  • an embodiment of the present application provides a communication device, which can implement the method in the fourth aspect or any possible implementation manner of the fourth aspect.
  • the apparatus comprises corresponding units or components for carrying out the above-described method.
  • the units included in the apparatus may be implemented by software and/or hardware.
  • the apparatus may be, for example, an SMF, or a chip, a system-on-a-chip, or a processor that can support the SMF to implement the fourth aspect or any possible method of the fourth aspect.
  • the structure of the communication device may include a communication module, a processing module, etc., and these modules may perform the corresponding functions of the SMF in the fourth aspect or each possible design example of the fourth aspect.
  • the communication module can be used for the communication device to perform reception and transmission of signals, data, information or messages
  • the processing module can be used to process the signals, data, information or messages received by the communication module, or to generate a signal sent by the communication module. Signal, data, information or message.
  • the processing module may establish a first PDU session associated with the DNN and the S-NSSAI of the terminal device registered with the first network.
  • the first PDU session is a PDU session between a first access network element and a first UPF, and the first access network element belongs to the first network.
  • the communication module may receive a fourth PDU session request message, where the fourth PDU session request message includes a request type information element whose value is the existing PDU session, or in other words, the fourth PDU session request message may be used to request the establishment of an existing PDU session.
  • the fourth PDU session request message also includes the information of the DNN and the information of the S-NSSAI to request to establish a PDU session associated with the DNN and the S-NSSAI.
  • the communication module may also send second information to the first UPF, where the second information is used to instruct the first UPF to send an end marker to the first access network element after the path switching of the first PDU session, and is used to indicate The first UPF forwards downlink data from the terminal device of the first access network element to the terminal device through the switched path, where the downlink data includes the end marker.
  • the communication module may also send third information to the first access network element, where the third information is used to instruct the first access network element to forward the downlink data of the terminal device buffered by the first access network element to the first UPF until the end marker is received and forwarded.
  • the fourth PDU session request message includes a lossless handover indication, or the processing module may determine to perform a lossless handover for the terminal device according to the local configuration.
  • the communication module may also receive a non-public network handover instruction.
  • the above fourth PDU request message comes from a first network device, and the first network device belongs to the second network.
  • the communication apparatus communicates with the second network, and the first network device communicates with the second network. device connection.
  • the fourth PDU session request message is sent by the first network device to the intermediate SMF, and forwarded by the intermediate SMF to the communication module.
  • the communication device does not belong to the second network, and the first network device and the communication device are not connected.
  • Direct connection requires message forwarding through an intermediate SMF.
  • the structure of the communication device may include a processor, and optionally a communication interface and a memory.
  • the communication interface can be used for sending and receiving information or data, and for the communication device to communicate and interact with other communication devices (eg, the first network device) in the network system.
  • the processor is configured to support the communication apparatus to perform the corresponding functions of the SMF in the fourth aspect or each possible design example of the fourth aspect above.
  • the memory is coupled to the processor for storing necessary program instructions and data for the communication device.
  • the transceiver may be configured to perform the steps performed by the communication module described in the eighth aspect above, and the processor may be configured to perform the steps performed by the processing module described in the foregoing eighth aspect.
  • an embodiment of the present application provides a communication method, and the method can be implemented by a terminal device or a component of the terminal device (such as a chip, a circuit, and other components).
  • the terminal device may be a UE.
  • the terminal device registered in the first network establishes the first PDU session associated with the DNN and the S-NSSAI in the first network; the terminal device reports to the first network
  • the device sends a first message, the first message is used to request registration to the second network;
  • the terminal device receives the first information from the first network device, the first information is based on the first network and the The intercommunication mode between the second networks is determined, and there is no roaming intercommunication between the first network and the second network;
  • the terminal device determines, according to the first information, to restore the terminal in a manner that supports N3WIF
  • the PDU session of the device or it is determined that the PDU session of the terminal device is no longer established, and the PDU session is associated with the DNN and the S-NSSAI.
  • the terminal device may send a third message to the first network device, where the third message is used to request the establishment of a second PDU session; the terminal device passes the second PDU session establishing a connection with the N3IWF, where the N3IWF belongs to the first network; the terminal device sends a fourth message to the second network device through the connection, where the fourth message is used to request the first network registration, the second network device belongs to the first network; the terminal device may send a fifth message to the second network device, where the fifth message is used to request the establishment of an existing PDU session, the first The fifth message includes the information of the DNN and the information of the S-NSSAI.
  • the first information is used to indicate that non-roaming interworking is not supported between the first network and the second network.
  • an embodiment of the present application provides a communication method, and the method can be executed by a first network device or a component thereof.
  • the first network device may include an AMF.
  • a first network device can receive a first message from a terminal device, the first network device belongs to a second network, and the first message is used to request registration to the second network; the first The network device acquires the identifier of the terminal device, and determines the identifier of the first network; the first network device sends the first information to the terminal device according to the roaming interworking mode between the first network and the second network.
  • an embodiment of the present application provides a communication device, which can implement the method in the ninth aspect or any possible implementation manner of the ninth aspect.
  • the apparatus comprises corresponding units or components for carrying out the above-described method.
  • the units included in the apparatus may be implemented by software and/or hardware.
  • the apparatus may be, for example, a terminal device, or a chip, a chip system, or a processor that can support the terminal device to implement the above method.
  • the structure of the communication apparatus may include a communication module, a processing module, etc., and these modules may perform the corresponding functions of the terminal device in the first aspect or each possible design example of the first aspect.
  • the communication module can be used for the communication device to perform reception and transmission of signals, data, information or messages
  • the processing module can be used to process the signals, data, information or messages received by the communication module, or to generate a signal sent by the communication module. Signal, data, information or message.
  • the communication module of the terminal device registered in the first network establishes the first PDU session associated with the DNN and the S-NSSAI in the first network; the communication module sends the first PDU to the first network device.
  • a message, the first message is used to request registration to the second network;
  • the communication module receives first information from the first network device, the first information is based on the first network and the second network
  • the intercommunication mode between the two networks is determined, and the first network and the second network do not roam and intercommunicate;
  • the processing module determines, according to the first information, to restore the PDU session in a manner that supports N3WIF, or to not establish the A PDU session of a terminal device, the PDU session is associated with the DNN and the S-NSSAI.
  • the communication module may be configured to send a third message to the first network device, where the third message is used to request the establishment of a second PDU session; the communication module establishes and communicates with the N3IWF through the second PDU session
  • the N3IWF belongs to the first network; the communication module sends a fourth message to the second network device through the connection, and the fourth message is used to request to register in the first network by means of N3GPP, and the The second network device belongs to the first network; the communication module may send a fifth message to the second network device, where the fifth message is used to request the establishment of an existing PDU session, and the fifth message includes the information of the DNN. information and the information of the S-NSSAI.
  • the first information is used to indicate that the first network does not support non-roaming interworking.
  • an embodiment of the present application provides a communication device, which can implement the method in the tenth aspect or any possible implementation manner of the tenth aspect.
  • the apparatus comprises corresponding units or components for carrying out the above-described method.
  • the units included in the apparatus may be implemented by software and/or hardware.
  • the apparatus may be, for example, a first network device, or a chip, a chip system, or a processor that can support the first network device to implement the tenth aspect or any of the possible methods of the tenth aspect.
  • the communication module may receive a first message from a terminal device, where the first network device belongs to a second network, and the first message is used to request to register with the second network ; the first network device obtains the identifier of the terminal device, and determines the identifier of the first network; the communication module sends the first information to the terminal device according to the roaming intercommunication mode between the first network and the second network.
  • an embodiment of the present application provides a communication system.
  • the communication system may include the communication device provided in the fifth aspect and the communication device provided in the sixth aspect.
  • the communication system further includes the communication device provided in the eighth aspect.
  • the communication system may include the communication device provided in the eleventh aspect and the communication device provided in the twelfth aspect.
  • an embodiment of the present application provides a communication system.
  • the communication system may include the communication apparatus provided in the seventh aspect and the first network device.
  • the communication system further includes the communication device provided in the eighth aspect.
  • the present application provides a computer storage medium, where a program is stored in the computer storage medium or, when it is invoked and executed on a computer, the computer enables the computer to execute the above-mentioned first aspect and its possible designs, the second aspect and its possible designs, the third aspect and its possible designs, or the fourth aspect and its possible designs, or the ninth aspect and its possible designs, or the tenth aspect and its possible designs Methods.
  • the present application provides a computer program product
  • the computing basic product may include programs or instructions, when the computer program product is run on a computer, the computer is made to execute the above-mentioned first aspect and its possible designs, the third The second aspect and its possible designs, the third aspect and its possible designs, or the fourth aspect and its possible designs, or the ninth aspect and its possible designs, or any of the tenth aspect and its possible designs method described.
  • the beneficial effects in the above-mentioned twelfth aspect and its possible designs may refer to the first aspect and its possible designs.
  • the method described in the third aspect and its possible designs for the beneficial effects of the twelfth aspect and its possible designs, reference may be made to the method described in the third aspect and its possible designs. Description of beneficial effects.
  • the beneficial effects of the twelfth aspect and its possible designs reference may be made to the method described in the third aspect and its possible designs. Description of beneficial effects.
  • the present application provides a chip or a chip system (or circuit) including a chip, and the chip may include a processor.
  • the chip may also include memory (or storage modules) and/or transceivers (or communication modules).
  • the chip can be used to implement the first aspect and its possible designs, the second aspect and its possible designs, the third aspect and its possible designs, or the fourth aspect and its possible designs, or the ninth aspect and its possible designs , or the method of any one of the tenth aspect and possible designs thereof.
  • the chip system may be composed of the above-mentioned chips, and may also include the above-mentioned chips and other discrete devices, such as memories (or storage modules) and/or transceivers (or communication modules).
  • the beneficial effects in the above-mentioned twelfth aspect and its possible designs may refer to the first aspect and its possible designs.
  • the method described in the third aspect and its possible designs for the beneficial effects of the twelfth aspect and its possible designs, reference may be made to the method described in the third aspect and its possible designs. Description of beneficial effects.
  • the beneficial effects of the twelfth aspect and its possible designs reference may be made to the method described in the third aspect and its possible designs. Description of beneficial effects.
  • a tenth aspect provides a communication system, the communication system includes a first terminal device, a second terminal device, the third aspect, any possible implementation manner of the third aspect, the fourth aspect and the fourth aspect The communication device described in any possible implementation manner.
  • FIG. 1 is a schematic diagram of the architecture of a communication system provided by an embodiment of the present application.
  • FIG. 2 is a schematic diagram of the architecture of another communication system provided by an embodiment of the present application.
  • FIG. 3 is a schematic diagram of the architecture of another communication system provided by an embodiment of the present application.
  • FIG. 4 is a schematic diagram of the architecture of another communication system provided by an embodiment of the present application.
  • FIG. 5 is a schematic diagram of the architecture of another communication system provided by an embodiment of the present application.
  • FIG. 6 is a schematic diagram of the architecture of another communication system provided by an embodiment of the present application.
  • FIG. 7a is a schematic diagram of the architecture of another communication system provided by an embodiment of the present application.
  • FIG. 7b is a schematic diagram of the architecture of another communication system provided by an embodiment of the present application.
  • FIG. 7c is a schematic diagram of the architecture of another communication system provided by an embodiment of the present application.
  • FIG. 8 is a schematic diagram of the architecture of another communication system provided by an embodiment of the present application.
  • FIG. 9 is a schematic diagram of the architecture of another communication system provided by an embodiment of the present application.
  • FIG. 10 is a schematic flowchart of a communication method provided by an embodiment of the present application.
  • FIG. 11 is a schematic flowchart of another communication method provided by an embodiment of the present application.
  • FIG. 13 is a schematic flowchart of another communication method provided by an embodiment of the present application.
  • FIG. 15 is a schematic structural diagram of a communication device according to an embodiment of the present application.
  • FIG. 16 is a schematic structural diagram of another communication apparatus provided by an embodiment of the present application.
  • the present application provides a communication method.
  • the present application will be described in further detail below with reference to the accompanying drawings. It should be understood that the specific operation methods in the method embodiments described below can also be applied to the apparatus embodiments or the system embodiments.
  • the next generation (ie 5G) mobile communication system architecture (next generation, NextGen/NG) consists of UE (or NextGen UE), (radio) access network, (R)AN/NextGen(R) AN), core network (core/NextGen core) and data network (DN), among which, UE, access network and core network are the main components of the architecture, and logically they can be divided into user plane and control plane Two parts, the control plane is responsible for the management of the mobile network, and the user plane is responsible for the transmission of service data.
  • the NG2 reference point is located between the access network control plane and the core network control plane, the NG3 reference point is located between the access network user plane and the core network user plane, and the NG6 reference point is located between the core network user plane and the data network.
  • the UE is the portal for the mobile user to interact with the network, and can provide basic computing capabilities, storage capabilities, display service windows to users, and accept user operation inputs.
  • NextGen UE will use new air interface technology to establish signal connection and data connection with AN, so as to transmit control signals and service data to the mobile network.
  • the access network is similar to the base station in the traditional network. It is deployed close to the UE to provide network access functions for authorized users in a specific area, and can determine transmission tunnels of different quality to transmit user data according to the user's level and service requirements.
  • the AN can manage its own resources, utilize them rationally, provide access services for the UE on demand, and is responsible for forwarding control signals and user data between the UE and the core network.
  • the core network is responsible for maintaining the subscription data of the mobile network, managing the network elements of the mobile network, and providing functions such as session management, mobility management, policy management, and security authentication for the UE.
  • the UE When the UE is attached, it provides network access authentication for the UE; when the UE has a service request, it allocates network resources for the UE; when the UE moves, it updates the network resources for the UE; when the UE is idle, it provides a fast recovery mechanism for the UE;
  • a data network is a network that provides business services for users.
  • the client is located in the UE, and the server is located in the data network.
  • the data network can be a private network, such as a local area network, or an external network that is not controlled by operators, such as the Internet, or a private network jointly deployed by operators, such as an Internet protocol (IP) multimedia network sub-network.
  • IP Internet protocol
  • UE is a device with wireless transceiver function, which can be deployed on land, including indoor or outdoor, handheld, wearable or vehicle-mounted; it can also be deployed on water (such as ships, etc.); it can also be deployed in the air (such as airplanes) , balloon and satellite etc.
  • the terminal equipment can communicate with the core network through the radio access network (RAN), and exchange voice and/or data with the RAN.
  • RAN radio access network
  • the terminal equipment can be a mobile phone (mobile phone) , tablet computer (Pad), computer with wireless transceiver function, mobile internet device (MID), wearable device, virtual reality (VR) terminal device, augmented reality (AR) terminal device , wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical, wireless terminals in smart grid, transportation security wireless terminals in safety), wireless terminals in smart cities, wireless terminals in smart homes, etc.
  • the embodiments of this application do not limit application scenarios.
  • the embodiments of this application do not limit the application scenarios.
  • the specific technology, equipment form and name used by the equipment are not limited.
  • the access network may include access network equipment.
  • An access network device is a device in the network for connecting a terminal device to a wireless network.
  • the access network device may be a node in a radio access network, and may also be referred to as a base station, and may also be referred to as a radio access network (radio access network, RAN) node (or device).
  • radio access network radio access network
  • the network equipment may include an evolved base station (NodeB or eNB or e-NodeB, evolutional Node B) in a long term evolution (long term evolution, LTE) system or an evolved LTE system (LTE-Advanced, LTE-A), such as traditional Macro base station eNB and micro base station eNB in heterogeneous network scenarios, or may also include the next generation node B (next generation node B) in the fifth generation mobile communication technology (5th generation, 5G) new radio (new radio, NR) system , gNB), or may also include radio network controller (radio network controller, RNC), node B (Node B, NB), base station controller (base station controller, BSC), base transceiver station (base transceiver station, BTS) , transmission reception point (TRP), home base station (for example, home evolved NodeB, or home Node B, HNB), baseband unit (base band unit, BBU), baseband pool BBU pool, or WiFi access point ( access point, AP), etc
  • CU supports radio resource control (RRC), packet data convergence protocol (PDCP), service data adaptation protocol (service data adaptation) protocol, SDAP) and other protocols;
  • DU mainly supports radio link control layer (radio link control, RLC), media access control layer (media access control, MAC) and physical layer protocols.
  • the core network may include the following network elements or nodes:
  • the access management network element (the embodiment of this application may also be referred to as the access mobility management network element) is mainly used for the attachment, mobility management, and tracking area update procedures of the terminal in the mobile network.
  • Access stratum non access stratum, NAS
  • NAS non access stratum
  • the access management network element can be an access and mobility management function (AMF).
  • AMF access and mobility management function
  • future communication systems such as 6G communication systems
  • the mobility management network element may still be the AMF network element, or may have other names, which are not limited in this application.
  • the session management network element is mainly used for session management in the mobile network, such as session establishment, modification and release. Specific functions include allocating Internet Protocol (IP) addresses to terminals, and selecting user plane network elements that provide packet forwarding functions.
  • IP Internet Protocol
  • the session management network element may be a session management function (SMF).
  • SMF session management function
  • the session management network element may still be an SMF network element, or it may be With other names, this application is not limited.
  • User plane NEs are mainly used to process user packets, such as forwarding, accounting, and lawful interception.
  • the user plane network element may also be referred to as a protocol data unit (protocol data unit, PDU) session anchor (PDU session anchor, PSA).
  • PDU protocol data unit
  • PSA protocol data unit
  • the user plane network element may be a user plane function (UPF).
  • UPF user plane function
  • the user plane network element may still be a UPF network element, or it may be With other names, this application is not limited.
  • Policy control network element including user subscription data management function, policy control function, charging policy control function, quality of service (quality of service, QoS) control, etc.
  • the policy control network element may be a policy control function (PCF).
  • PCF policy control function
  • the policy control network element may still be a PCF network element, or it may be With other names, this application is not limited.
  • the network slice selection function network element is mainly used to select the appropriate network slice for the service of the terminal device.
  • the network slice selection network element may be the network slice selection function (NSSF) network element.
  • the network slice selection network element may still be the NSSF network element.
  • the network element may also have other names, which is not limited in this application.
  • the network storage function network element is mainly used to provide the registration and discovery functions of the network element or the services provided by the network element.
  • the network storage function network element may be a network repository function (NRF).
  • NRF network repository function
  • the network storage function network element may still be an NRF network element, or It can also have other names, which is not limited in this application.
  • Network data analysis network elements can be analyzed from various network functions (network functions, NF), such as policy control network elements, session management network elements, user plane network elements, access management network elements, and application function network elements (through the network capability opening function). network elements) to collect data and make analysis and predictions.
  • network functions such as policy control network elements, session management network elements, user plane network elements, access management network elements, and application function network elements (through the network capability opening function). network elements) to collect data and make analysis and predictions.
  • the network data analysis network element may be the network data analysis function (NWDAF).
  • NWDAF network data analysis function
  • the network data analysis network element may still be the NWDAF network element. , or may have other names, which are not limited in this application.
  • the unified data management network element is mainly used to manage the subscription information of terminal equipment.
  • the unified data management network element may be a unified data management (UDM), and in a future communication system (such as a 6G communication system), the unified data management network element may still be a UDM network element, or It can also have other names, which is not limited in this application.
  • UDM unified data management
  • the unified data storage network element is mainly used to store structured data information, including subscription information, policy information, and network data or service data defined in a standard format.
  • the unified data storage network element may be a unified data repository (UDR).
  • the unified data storage network element may still be a UDR network element, or It can also have other names, which is not limited in this application.
  • the authentication service function network element is mainly used to perform security authentication on terminal equipment.
  • the authentication service function network element may be an authentication server function (AUSF).
  • AUSF authentication server function
  • the authentication service function network element may still be an AUSF network element, or It can also have other names, which is not limited in this application.
  • the network capability exposure network element can expose some functions of the network to applications in a controlled manner.
  • the network capability exposure network element may be the network capability exposure function (NEF).
  • the network capability exposure network element may still be the NEF network element. Alternatively, it may have other names, which are not limited in this application.
  • the application function network element can provide service data of various applications to the control plane network element of the operator's communication network, or obtain network data information and control information from the control plane network element of the communication network.
  • the application function network element may be an application function (AF), and in the future communication system (such as a 6G communication system), the application function network element may still be the AF network element, or may also have other The name is not limited in this application.
  • the data network is mainly used to provide data transmission services for terminal equipment.
  • the data network can be a private network, such as a local area network, or a public data network (PDN) network, such as the Internet (Internet), or a private network jointly deployed by operators, such as a configured IP multimedia network sub-network.
  • PDN public data network
  • IMS IP multimedia core network subsystem
  • network elements or functions may be network elements in hardware devices, software functions running on dedicated hardware, or virtualized functions instantiated on a platform (eg, a cloud platform).
  • a platform eg, a cloud platform
  • the foregoing network element or function may be implemented by one device, or may be implemented jointly by multiple devices, or may be a functional module in one device, which is not specifically limited in this embodiment of the present application.
  • the access management network element is the AMF network element
  • the network slice selection function network element is the NSSF network element as an example for description.
  • AMF AMF
  • NSSF NSSF
  • the AMF described later in this application can be replaced by an access management network element
  • the NSSFF can be replaced by a network slice selection function network element.
  • the user plane of the communication system may include a user plane function (UPF), and the control plane of the core network may include an authentication server function (AUSF) ), core access and mobility management function (AMF), session management function (SMF), network slice selection function (NSSF), network open function ( network exposure function (NEF), network function repository function (NRF), unified data management (UDM), policy control function (PCF) and application function (AF) .
  • UPF user plane function
  • AUSF authentication server function
  • AMF core access and mobility management function
  • SMF session management function
  • NSSF network slice selection function
  • NEF network exposure function
  • NRF network function repository function
  • UDM unified data management
  • PCF policy control function
  • AF application function
  • the core network control plane adopts a service-based architecture, and the interaction between network elements of the control plane adopts a service invocation method to replace the point-to-point communication method in the traditional architecture.
  • the control plane network elements will open services to other control plane network elements for other control plane network elements to call; in point-to-point communication, there will be a set of specific messages on the communication interface between the control plane network elements, which can only be used by other control plane network elements.
  • the control plane NEs at both ends of the interface are used for communication.
  • the UPF can be used to perform user data packet forwarding according to the routing rules of the SMF, such as sending uplink data to DN or other UPFs, and/or forwarding downlink data to other UPFs or RANs.
  • AUSF can be used to perform security authentication of the UE.
  • AMF can be used for UE access management and mobility management (MM), responsible for UE state maintenance, UE reachability management, and non-MM non-access-stratum (NAS) message forwarding , SMN2 message forwarding.
  • MM UE access management and mobility management
  • NAS non-MM non-access-stratum
  • SMF can be used for UE session management, allocate resources for UE sessions, and release resources; the resources include session QoS, session paths, forwarding rules, and the like.
  • NSSF can be used to select network slices for the UE.
  • NEF can be used to open network functions to third parties in the form of northbound application programming interface (API) interfaces.
  • the NRF can be used to provide the storage function and selection function of network function entity information for other network elements.
  • UDM can be used for user subscription context (or subscription data, UE context, etc.) storage and management.
  • PCF can be used for user policy management.
  • AF can be used for application management.
  • the current NPN network includes PNI-NPN and SNPN.
  • PNI-NPN can be implemented using network slicing in PLMN.
  • a closed access group (CAG) function is additionally used.
  • a CAG can be used to identify a group of users who are allowed to access cells associated with the CAG (ie, CAG cells).
  • CAG cells In order to prevent the UE that is not allowed to access the CAG cell from automatically selecting and accessing the CAG cell, the CAG cell broadcasts one or more CAG identifiers (identifier, ID), and the available CAG list (list) and indication (used to indicate the UE) are configured on the UE. Whether to allow access to 5GS only through the CAG cell), the UE subscription data on the UDM includes the available CAG list and indication.
  • the SNPN network is independently deployed and does not depend on the PLMN network.
  • the SNPN network is identified by the PLMN ID and the network identifier (NID), where the PLMN ID can be an inherent value reserved by a third-party operator, or it can be the PLMN where the SNPN is deployed. Carrier specific value.
  • NID network identifier
  • its cell broadcasts the PLMN ID and NID, and the UE selects the NPN network to access according to the broadcast information and the configured network selection information. If the UE finds that the combination of PLMN ID and NID1 included in the configured network selection information is different from the PLMN ID broadcast by the network or the combination of PLMN ID and NID2, the UE will not select its access.
  • the PNI-NPN restricts the access of the UE by broadcasting the CAG ID and configuring the CAG ID available to the UE, while the SNPN allows the UE to correctly select the cell and network by broadcasting the PLMN ID and NID.
  • R16 currently supports interworking between SNPN and PLMN through the N3IWF architecture, and UE can sign up to SNPN and PLMN respectively.
  • the UE can use the private network subscription of the SNPN to select the SNPN ID, access the SNPN base station, and perform 3GPP registration in the SNPN network.
  • the UE can use the public network subscription of the PLMN to select the PLMN ID, select the PLMN N3IWF, establish a PDU session on the SNPN network to access the PLMN N3IWF, and perform N3GPP registration on the PLMN network.
  • the SNPN under R17 needs to support the terminal to use "external subscription" to access the SNPN network, that is, the user of the terminal subscribes to an external entity (such as a mobile network operator, MNO) independent of the SNPN network. Owned, the SNPN network allows such terminals to access the SNPN using an external subscription.
  • an external entity such as a mobile network operator, MNO
  • the SNPN network entity such as AMF/SMF
  • the PLMN network entity such as UDM/AUSF
  • the roaming architecture is used to support the intercommunication between SNPN and PLMN.
  • the UE only subscribes to the PLMN, and the subscription data can be stored in the UDM of the PLMN, as shown in Figure 2:
  • the UE uses the public network of the PLMN to subscribe to select the SNPN ID, and select the SNPN base station , register in the SNPN network, and establish a PDU session in the SNPN.
  • the SNPN network determines the local break out (LBO)/home routed (HR) mode according to the UE public network subscription.
  • the user subscription of the terminal is provided by the PLMN, it can also be provided by the SNPN network of a third party.
  • the intercommunication of the two SNPNs is similar to the above description.
  • AAA-server authentication, authorization, accounting server
  • AAA-S authentication, authorization, accounting server
  • AAA-P AAA proxy
  • the UE moves between two SNPNs, both of which may be connected to the PLMN, SNPN or AAA server holding the UE's subscription as shown above.
  • SNPN#2 may also be the SNPN that holds the UE subscription.
  • the UE can also move between the SNPN and the PLMN.
  • the PLMN can be a VPLMN or a home PLMN (home PLMN, HPLMN) where the UE subscription is stored.
  • Figures 6 to 9 show several typical UE mobility scenarios across private networks.
  • the UE can move from SNPN#1 to SNPN#2.
  • the subscription of the UE is stored by a third-party AAA server, and SNPN#1 and SNPN#2 can be connected to this AAA server.
  • the roaming interworking mode shown in FIG. 2 is supported between SNPN#1 and SNPN#2.
  • the UE can move from SNPN#1 to SNPN#2 or a visited PLMN (visited PLMN, VPLMN).
  • the UE subscription is stored by the UDM of the HPLMN, and the SNPN#1 and SNPN#2 or the VPLMN can be connected to the HPLMN.
  • the N3IWF interworking mode shown in Figure 1 is supported between SNPN#1 and SNPN#2 or VPLMN.
  • the UE can move from SNPN#1 to SNPN#2 or the visited PLMN.
  • the UE subscription is stored by the UDM of the HPLMN, and the SNPN#1 and SNPN#2 or the VPLMN can be connected to the HPLMN.
  • the UE can establish HR PDU session through SNPN#1, SNPN#2/VPLMN, that is, the PDU session of the anchor UPF in HPLMN.
  • the UE can move between SNPN#1 and SNPN#2.
  • the UE subscription is stored by the UDM of the HPLMN, and SNPN#1 and SNPN#2 can be connected to the HPLMN. Roaming and interworking between SNPN#1 and HPLMN, and communication between SNPN#2 and HPLMN through N3IWF.
  • the UE can establish an HR PDU session through SNPN#1, that is, the PDU session of the anchor UPF at the HPLMN.
  • the UE may establish a PDU session to the HPLMN in the manner shown in FIG. 1 .
  • the UE can move from SNPN#1 to HPLMN.
  • the UE subscription is preserved by the UDM of the HPLMN.
  • the roaming interworking mode shown in Figure 2 is supported between the SNPN#1 and the HPLMN.
  • the UE can move from SNPN#1 to HPLMN.
  • the UE subscription is preserved by the UDM of the HPLMN.
  • Core network elements such as AMF and SMF, are shared between SNPN#1 and HPLMN.
  • the UE can continue to move from the HPLMN to the VPLMN, and the roaming interworking mode shown in FIG. 2 is adopted between the HPLMN and the VPLMN.
  • the present application provides a communication method, which is used to solve the problem that the handover efficiency of the UE between cross-NPN networks is not high or cannot be correctly handed over.
  • the communication method may be performed by a terminal device, a first network device, and the like.
  • the terminal device is registered in the first network (or called the source network or the home network), and the first network device belongs to the second network (or called the destination network).
  • the first network and/or the second network are NPN networks. Therefore, when the terminal device performs cross-non-public network handover between the first network and the second network, the handover can be improved according to the communication method provided in the embodiment of the present application. Efficiency and success rate. It should be understood that, for scenarios in which the terminal device switches between the first network and the second network, reference may be made to the scenarios shown in FIGS. 6-9 .
  • a communication method provided by this embodiment of the present application may include the following steps shown in FIG. 10 :
  • S101 The UE establishes a first PDU session in a first network.
  • the first PDU session is associated with a data network name (DNN) and a single network slice selection assistance information (S-NSSAI).
  • DNN data network name
  • S-NSSAI single network slice selection assistance information
  • the present application does not specifically limit the process of establishing the first PDU session.
  • S102 The UE sends a first registration request message to the first network device in the second network.
  • the first network device receives the first registration request message.
  • the first registration request message may be used to request registration to the second network.
  • the first network device is an AMF deployed in the second network.
  • the first registration request message may carry a cross-non-public network handover indication (or a cross-private network handover indication), where the cross-non-public network handover indication is used to instruct the terminal device to perform cross-non-public network handover.
  • a cross-non-public network handover indication or a cross-private network handover indication
  • the first network device acquires the context of the UE.
  • the context of the UE may be stored in the second network device of the first network, or stored in a data storage node.
  • the second network device is, for example, deployed in an AMF of the first network, where the AMF can manage the registration request of the UE in the first network.
  • the first network device may obtain the information of the UE registered in the first network, such as the temporary identity, from the UDM, and then obtain the information of the second network device, so as to obtain the context of the UE through the second network device.
  • the data storage node can be shared by the first network and the second network, so the context of the UE previously registered in the first network can be obtained by the first network device, for example, the data storage node is deployed in the second network and is shared by the first network and the second network
  • the network is shared (that is, the context of the UE registered in the first network and the second network is stored), or the data storage node may be deployed in a third network other than the first network and the second network, and the first network and the second network network sharing.
  • the data storage node is eg UDM or AAA.
  • the first network device determines that the UE has registered with the first network according to the context of the UE.
  • the UE context may include the identity of the first network or the identity of the second network device, and the first network device may learn that the UE has registered with the first network according to the identity of the first network or the identity of the second network device.
  • the first network device determines the first information according to the communication mode between the first network and the second network.
  • the first information may indicate how to switch PDU sessions during the UE registration process.
  • the intercommunication mode between the first network and the second network includes: no intercommunication between the first network and the second network, intercommunication between the first network and the second network based on the N3IWF shown in FIG. 1 , and, The first network and the second network communicate based on roaming.
  • the first information is different if the communication modes between the first network and the second network are different.
  • the first information may indicate that the first network and the second network do not communicate with each other, for example, the first information is indicating information that the first network and the second network do not communicate with each other.
  • the first information may instruct the UE to send the first PDU session request to the first network device.
  • the first PDU session request includes a request type (request type information element) whose value is an initial request (initial request), or in other words, the first PDU session request is used to request to establish an initial PDU session.
  • the first PDU session request message includes the information of the DNN and the information of the S-NSSAI, or in other words, the first PDU session request message includes the information of the DNN associated with the PDU session established by the UE in the first network and the PDU Information about the S-NSSAI associated with the session.
  • the first information may indicate N3IWF-based interworking between the first network and the second network, for example, the first information is N3IWF-based interworking indication information.
  • the first information may instruct the UE to send a second PDU session request to the first network device, to send a second registration request to the second network device through the N3IWF, and to send a third PDU session request message to the second network device.
  • the second PDU session request is used to request to establish a second PDU session, and the UE can establish a connection between the UE and the N3IWF through the second PDU session.
  • the second registration request may be used to request to register with the first network by means of N3GPP.
  • the third PDU session request message includes a request type whose value is an existing PDU session (existing PDU session). In other words, the third PDU session request message is used to establish an existing PDU session.
  • the third PDU session request message includes the information of the DNN and the information of the S-NSSAI, or in other words, the third PDU session request message includes the information of the DNN associated with the PDU session established by the UE in the first network and the PDU Information about the S-NSSAI associated with the session.
  • the first information may indicate roaming-based interworking between the first network and the second network, for example, the first information is roaming-based interworking indication information.
  • the first information may be used to instruct the UE to send a fourth PDU session request message to the first network device.
  • the fourth PDU session request message includes a request type information element whose value is the existing PDU session, or in other words, the fourth PDU session request message is used to request the establishment of an existing PDU session.
  • the fourth PDU session request message includes the information of the DNN and the information of the S-NSSAI, or in other words, the fourth PDU session request message includes the information of the DNN associated with the PDU session established by the UE in the first network and the PDU Information about the S-NSSAI associated with the session.
  • the first network device sends the first information to the UE.
  • the UE receives the first information from AMF#2, where the first information is determined according to the interworking mode between SNPN#1 and SNPN#2.
  • the UE establishes a PDU session of the UE according to the first information, and the PDU session is associated with the DNN and the S-NSSAI.
  • the first information indicates that the first network and the second network do not communicate with each other, or the UE is instructed to send the first network device to the first network device.
  • the UE may send a first PDU session request message to the first network device, where the first PDU session includes a request type information element whose value is initial request and the information of the DNN and the information of the S-NSSAI.
  • the UE can create a new PDU session associated with the DNN and the S-NSSAI on the second network to restore the PDU session associated with the DNN and the S-NSSAI. Since both N3IWF interworking and roaming interworking-based PDU session recovery modes are infeasible in the non-interworking mode, the UE performs a corresponding handover process according to the first information to improve handover efficiency and avoid trial and error.
  • the first information is used to indicate the N3IWF-based interworking between the first network and the second network, or instruct the UE to communicate with the first network device
  • the UE may send the second PDU session request to the first network device.
  • the second PDU session request is used to request the establishment of a second PDU session.
  • the UE may also establish a connection with the N3IWF through the second PDU session, the N3IWF belonging to the first network.
  • the UE may send a second registration request to the second network device through the connection, where the second registration request is used to request to register with the first network by means of N3GPP.
  • the UE may also send a third PDU session request message to the second network device, an existing PDU session has been established (the PDU session may be referred to as a third PDU session), and the third PDU drawing request message may include the information of the DNN and the Information on S-NSSAI.
  • the UE can establish the information associated with the DNN and the third PDU session of the S-NSSAI through the N3IWF and the second network device, so as to realize the association of the UE to the The DNN and S-NSSAI's PDU session is resumed. Since both the non-interworking and roaming-based PDU session recovery modes are infeasible in the N3IWF interworking mode, the UE performs the corresponding handover process according to the first information to improve the handover efficiency and avoid trial and error.
  • the first information is used to indicate roaming-based interworking between the first network and the second network, or instruct the UE to communicate with the first network device
  • the UE may send the fourth PDU session request message to the first network device.
  • the fourth PDU session request message includes a request type information element whose value is existing PDU session, or in other words, the fourth PDU session request message is used to request the establishment of an existing PDU session (this PDU session may be referred to as a fourth PDU session) .
  • the fourth PDU session request message includes the information of the DNN and the information of the S-NSSAI.
  • the UE can establish the information associated with the DNN and the fourth PDU session of the S-NSSAI through the first network device, so as to realize the association of the UE with the DNN and the S-NSSAI. Restoration of PDU sessions for S-NSSAI. Since both the non-interworking and N3IWF-based PDU session recovery modes are infeasible in the roaming interworking mode, the UE performs the corresponding handover process according to the first information to improve the handover efficiency and avoid trial and error.
  • the UE can receive the first information from the first network device in the second network.
  • the interworking mode is related, and the PDU session associated with the DNN and the S-NSSAI of the UE can be recovered more efficiently according to the first information, so as to improve the handover efficiency and ensure service continuity.
  • one of the above first network and second network is an NPN network.
  • at least one of the first network and the second network is an SNPN.
  • the UE may carry the lossless handover indication in the fourth PDU session request message.
  • the lossless handover indication may also be sent independently of the fourth PDU session request message.
  • the first network device may send the lossless handover indication to the SMF, where the SMF is the SMF that manages the first PDU session; or the SMF is an intermediate SMF that is used to connect to the SMF that manages the first PDU session, and can be used by the intermediate SMF thereafter
  • the SMF forwards the lossless handover indication to the SMF managing the first PDU session.
  • the SMF managing the first PDU session may send second information to the first UPF to instruct the first UPF to send an end marker to the first access network element after the path of the first PDU session is switched , and is used to instruct the first UPF to forward downlink data from the UE of the first access network element to the UE through the switched path, where the downlink data includes the end marker.
  • the SMF managing the first PDU session may send third information to the first access network element to instruct the first access network element to forward the buffered downlink data of the UE to the first UPF until it is received and forwarded the closing tag.
  • the above first PDU session is a PDU session between the first access network element and the first UPF. Accordingly, the downlink data of the UE before the path switching can be forwarded to the UE by the first UPF and the first access network element through the path after the switching, so as to realize the lossless path switching.
  • the first network is SNPN#1 and the second network is SNPN#2 as an example for description, wherein the SNPN#2 here can also be replaced by VPLMN#2 (ie, a VPLMN).
  • VPLMN#2 ie, a VPLMN
  • a communication method provided by an embodiment of the present application may include the following processes:
  • S201 The UE registers with SNPN#1 and establishes a first PDU session.
  • the SMF and UPF of the first PDU session are SMF#1 and UPF#1, respectively.
  • the first PDU session may be associated with the first DNN and the first S-NSSAI.
  • S202 SMF#1 sends an SMF registration message to the UDM or AAA server.
  • the registration message may include the UE ID, SNPN#1 ID, SMF#1 ID, and the ID of the first PDU session.
  • the UDM or AAA server can be deployed in a PLMN or a third network.
  • S203 The UE moves to the target network SNPN#2, and the UE sends a first registration request message to AMF#2 in SNPN#2 (AMF#2 in FIG. 11 is used as the first network device), carrying the UE ID.
  • AMF#2 in FIG. 11 is used as the first network device
  • the first registration request message may carry a cross-private network HO indication.
  • the cross-private network HO indication is used to indicate that the purpose of AMF#2 registration is to perform cross-private network handover, rather than initial registration.
  • the HO indication can be registered for location update or a new cell.
  • AMF#2 can obtain the context of the UE from AMF#1, including the UE ID, SNPN#1 ID, SMF#1 ID or the ID of the first PDU session at least one message.
  • the information of AMF#1 can be obtained by AMF#2 from the UDM or AAA server. Otherwise, if there is no interface between AMF#2 and AMF#1, AMF#2 can obtain the UE's context from UDM or AAA.
  • AMF#2 determines that the UE is performing cross-private network handover according to the cross-private network HO indication of the UE or the UE context, such as SNPN#1 ID or SMF#1 ID, and according to the intercommunication mode between SNPN#2 and SNPN#1 ( No interworking, interworking based on N3IWF mode, or interworking based on roaming) to determine the handover mode, such as determining that the UE performs handover according to roaming interworking or not according to roaming interworking.
  • AMF#2 sends a registration response message to the UE, carrying a handover mode indication (ie, the first information).
  • the handover mode information may instruct the UE to perform handover in a non-communicative manner, or indicate that SNPN#1 and SNPN#2 do not communicate with each other; if SNPN#1 and SNPN# 2 based on the N3IWF mode, the handover mode information can instruct the UE to switch based on the N3IWF mode, or indicate the N3IWF-based intercommunication between SNPN#1 and SNPN#2; if SNPN#1 and SNPN#2 According to the roaming intercommunication, the handover mode information may instruct the UE to perform the handover according to the roaming intercommunication mode, or instruct the SNPN#1 and the SNPN#2 to perform the roaming intercommunication.
  • the UE If SNPN#1 and SNPN#2 do not communicate with each other, the UE re-establishes a PDU session, that is, sends a first PDU session request message with a request type of initial request to AMF#2.
  • the first PDU session request message carries the first DNN and the first S-NSSAI, so the newly established PDU session can be associated with the first DNN and the first S-NSSAI.
  • the handover mode indication can be used to indicate that SNPN#1 and SNPN#2 do not communicate with each other, or to instruct the UE to send the first PDU session request to AMF#2.
  • N3IWF-based PDU session that is, a second PDU session
  • the UE initiates N3GPP registration at SNPN#1 through the N3IWF, or, in other words, sends a second registration request to AMF#1 through the N3IWF to request to register with the first network through N3GPP, and then the UE can initiate the process of switching the PDU session from 3GPP to N3GPP , that is, initiate a third PDU session request message whose request type is existing PDU session, and carry the first DNN and the first S-NSSAI in the third PDU session request message, so the newly established N3GPP PDU session can be associated with the first DNN and the first S-NSSAI.
  • the handover mode indication can be used to instruct the N3IWF-based interworking between SNPN#1 and SNPN#2, or to instruct the UE to first establish an N3IWF-based PDU session connected to SNPN#1 at SNPN#2, and initiate an N3IWF-based PDU session.
  • S209 If the roaming interworking between SNPN#1 and SNPN#2 is based on roaming, the UE initiates the handover process of the PDU session from SNPN#1 to SNPN#2 at SNPN#2, that is, sends the request type of existing PDU session to AMF#2
  • the fourth PDU session request message after which S210-S220 are performed.
  • the fourth PDU session request message carries the information of the DNN and the information of the S-NSSAI, so as to request to restore the PDU session associated with the DNN and the S-NSSAI.
  • a lossless handover indication may be additionally carried in the fourth PDU session request.
  • the handover mode indication can be used to instruct the roaming-based interworking between SNPN#1 and SNPN#2, or to instruct the UE to initiate the handover procedure of the PDU session from SNPN#1 to SNPN#2 at SNPN#2.
  • AMF#2 determines that the UE is performing cross-private network handover according to the cross-private network HO indication, the request type of the existing PDU session, or the SMF#1 ID, and determines to insert the I-SMF.
  • AMF#2 sends an SMF discovery request message to the NRF.
  • the NRF sends the candidate SMF to AMF#2 according to the SMF discovery request message.
  • AMF#2 selects SMF#2 as the I-SMF according to the candidate SMF.
  • AMF#2 sends a fourth PDU session request message and a cross-private network HO indication to SMF#2.
  • S215 SMF#2 sends a fourth PDU session request message and a cross-private network HO indication to SMF#1.
  • SMF#2 may forward the lossless handover instruction to SMF#1.
  • SMF#2 when SMF#2 inserts UPF#2 as I-UPF (such as UPF#2) according to the existing mechanism, additionally, SMF#2 may configure charging rules on the I-UPF according to the HO instruction.
  • S216 SMF#1 sends a path switching instruction to UPF#1 to instruct UPF#1 to switch the path to the UE.
  • the path from UPF#1 to UE is switched from UPF#1 ⁇ RAN#1 ⁇ UE to UPF#1 ⁇ UPF#2 ⁇ RAN#2 ⁇ UE.
  • the SMF instructs UPF#1 to maintain service continuity through the second information according to the cross-private network HO instruction and the local configuration or lossless handover instruction.
  • UPF#1 After switching to the new path, UPF#1 sends an end marker to RAN#1 on the old path according to the second information of the SMF.
  • the old path here refers to the path between UPF#1 and RAN#1.
  • S218 SMF#1 (or AMF#1) sends a release request to RAN#1 to request RAN#1 to release the first PDU session.
  • SMF#1 may determine that a lossless handover is required according to the local configuration, and thus send a third indication to RAN#1 to instruct RAN#1 before releasing the context , and forward the buffered downlink data (including the end marker sent by UPF#1) to UPF#1. Subsequently, the data from RAN#1 can be forwarded to the UE by UPF#1 through the new path.
  • SMF#1/AMF#1 may use third information to instruct RAN#1 to send the buffered downlink data (including the end of UPF#1 transmission) before releasing the context. mark) to UPF#1. Subsequently, the data from RAN#1 can be forwarded to the UE by UPF#1 through the new path.
  • S219 RAN#1 forwards the buffered UE data to UPF#1, and releases the resources of the first PDU session, where the data includes an end marker.
  • UPF#1 forwards the data from RAN#1 to the UE on the new path, that is, the data is forwarded on the path of UPF#1 ⁇ UPF#2 ⁇ RAN#2 ⁇ UE.
  • the data of the subsequent UE passes through path forwarding.
  • UPF#1 receives the SMF switch path instruction, before forwarding new data in the downlink direction, it needs to forward the data from RAN#1 first, that is, UPF#1 first forwards the packets received from the original path, Until the end marker is received, the new downlink data packet is forwarded.
  • AMF#2 can instruct the UE to take the cross-private network handover mode, and the UE can instruct the cross-private network handover to perform the cross-private network handover through the indicated handover mode, so that the UE can correctly switch to the target network, so as to improve the cross-private network handover efficiency.
  • data lossless handover can be provided for the UE.
  • HPLMN#2 As shown in FIG. 12 , another communication method provided by the embodiment of the present application is described by taking the first network as SNPN#1 and the second network as HPLMN#2 as an example. Wherein, HPLMN#2 here can also be replaced with home SNPN (home SNPN, H-SNPN) H-SNPN#2, and this scenario is shown in FIG. 8 .
  • another communication method provided by this embodiment of the present application may include the following process:
  • S301 The UE registers with SNPN#1 through RAN#1, and establishes a first PDU session.
  • the SMF and UPF of the first PDU session are SMF#1 and UPF#1, respectively.
  • the first PDU session may be associated with the first DNN and the first S-NSSAI.
  • SMF#2 sends an SMF registration message to the UDM.
  • the registration message may include the UE ID, SNPN#1 ID, SMF#1 ID, and the ID of the first PDU session.
  • UDM is deployed in HPLMN#2.
  • the UE moves to the target network HPLMN#2, and the UE sends a first registration request message to AMF#2 in HPLMN#2 (AMF#2 in FIG. 12 is used as the first network device), carrying the UE ID.
  • the first registration request message may also carry a cross-private network HO indication.
  • the cross-private network HO indication is used to indicate that the purpose of AMF#2 registration is to perform cross-private network handover, rather than initial registration, and the HO indication may be location update registration or a new cell.
  • AMF#2 can obtain the context of the UE from AMF#1, including the UE ID, SNPN#1 ID, SMF#1 ID or the ID of the first PDU session At least one piece of information; otherwise, if there is no interface between AMF#2 and AMF#1, AMF#2 obtains the UE's context from UDM.
  • AMF#2 determines that the UE is performing cross-private network handover according to the UE's cross-private network HO indication or UE context, such as SNPN#1 ID or SMF#2 ID, and determines according to the interworking mode between HPLMN#2 and SNPN#1 Handover mode, wherein, the intercommunication mode of HPLMN#2 and SNPN#1 is roaming intercommunication.
  • AMF#2 sends a registration response message to the UE, carrying a handover mode indication (ie, the first information).
  • the handover mode information may instruct the UE to perform handover in a roaming intercommunication mode, or instruct the SNPN#1 and HPLMN#2 to perform handover in accordance with roaming intercommunication.
  • the UE initiates a handover process of the PDU session from SNPN#1 to HPLMN#2 at HPLMN#2, that is, sends a fourth PDU session request message whose request type is existing PDU session to AMF#2.
  • the fourth PDU session request message carries the information of the DNN and the information of the S-NSSAI, so as to request to restore the PDU session associated with the DNN and the S-NSSAI.
  • a lossless handover indication may be additionally carried in the session request.
  • AMF#2 determines that the UE is performing cross-private network handover according to the cross-private network HO indication, the request type of the existing PDU session, or the SMF#1 ID, and determines to insert the I-SMF.
  • AMF#2 sends an SMF discovery request to the NRF.
  • the NRF sends the candidate SMF to AMF#2 according to the SMF discovery request.
  • AMF#2 selects SMF#2 as the I-SMF according to the candidate SMF.
  • AMF#2 sends a fourth PDU session request message and a cross-private network HO indication to SMF#2.
  • SMF#2 sends a fourth PDU session request message and a cross-private network HO indication to SMF#2, and simultaneously sends a cross-private network HO indication to SMF#1.
  • SMF#2 may forward the lossless handover instruction to SMF#1.
  • SMF#2 when SMF#2 inserts UPF#2 as I-UPF (such as UPF#2) according to the existing mechanism, additionally, SMF#2 may configure charging rules on the I-UPF according to the HO instruction.
  • S314 SMF#1 sends a path switching instruction to UPF#1 to instruct UPF#1 to switch the path to the UE.
  • the path from UPF#1 to UE is switched from UPF#1 ⁇ RAN#1 ⁇ UE to UPF#1 ⁇ UPF#2 ⁇ RAN#2 ⁇ UE.
  • the SMF instructs UPF#1 to maintain service continuity through the second information according to the cross-private network HO instruction and the local configuration or lossless handover instruction.
  • UPF#1 may send an end marker on the old path to RAN#1 according to the second information.
  • the old path here refers to the path between UPF#1 and RAN#1.
  • S316 SMF#1 (or AMF#1) sends a release request to RAN#1 to request RAN#1 to release the first PDU session.
  • SMF#1 (or AMF#1) can determine that a lossless handover needs to be performed according to the local configuration, thereby instructing RAN#1 through the third information to store the buffered downlink data before releasing the context. (including the end marker sent by UPF#1) is forwarded to UPF#1.
  • SMF#1/AMF#1 may use third information to instruct RAN#1 to send the buffered downlink data (including the end of UPF#1 transmission) before releasing the context. mark) to UPF#1. Subsequently, the data from RAN#1 can be forwarded to the UE by UPF#1 through the new path.
  • S317 RAN#1 forwards the buffered UE data to UPF#1, where the data includes an end marker, and releases the resources of the first PDU session.
  • UPF#1 forwards the data from RAN#1 to the UE through the new path, that is, the data is forwarded on the path of UPF#1 ⁇ UPF#2 ⁇ RAN#2 ⁇ UE.
  • the data of the subsequent UE passes through path forwarding.
  • UPF#1 receives the SMF switch path instruction, before forwarding new data in the downlink direction, it needs to forward the data from RAN#1 first, that is, UPF#1 first forwards the packets received from the original path, Until the end marker is received, the new downlink data packet is forwarded.
  • the core network can instruct the UE to adopt a roaming-based cross-private network handover to improve the cross-private network handover efficiency.
  • data lossless handover can be provided for the UE.
  • the communication method provided by this embodiment of the present application may include the following steps as shown in FIG. 13 :
  • S401 The UE registers with SNPN#1 through RAN#1, and establishes a first PDU session.
  • the SMF and UPF of the first PDU session are SMF#2 and UPF#2, respectively.
  • the first PDU session may be associated with the first DNN and the first S-NSSAI.
  • SMF#2 sends an SMF registration message to the UDM.
  • the registration message may include the UE ID, SNPN#1 ID, SMF#2 ID, and the ID of the first PDU session.
  • the UE moves to the target network HPLMN#2, and the UE sends a first registration request message to AMF#2 in HPLMN#2 (AMF#2 in FIG. 13 is used as the first network device), carrying the UE ID.
  • the first registration request message may also carry a cross-private network HO indication.
  • the cross-private network HO indication is used to indicate that the purpose of AMF#2 registration is to perform cross-private network handover, rather than initial registration, and the HO indication may be a location update registration or a new information element.
  • S404: AMF#2 obtains the context of the UE from the UDM.
  • AMF#2 determines that the UE is performing cross-private network handover according to the cross-private network HO indication of the UE or the UE context, such as the SNPN#1 ID, and determines the handover method according to the interworking method between HPLMN#2 and SNPN#1, wherein, The intercommunication mode between HPLMN#2 and SNPN#1 is roaming intercommunication.
  • AMF#2 sends a registration response message to the UE, carrying a handover mode indication (ie, the first information).
  • the handover mode information may instruct the UE to perform handover in a roaming intercommunication mode, or instruct the SNPN#1 and HPLMN#2 to perform handover in accordance with roaming intercommunication.
  • the UE initiates a handover process of the PDU session from SNPN#1 to HPLMN#2 at HPLMN#2, that is, sends a fourth PDU session request message whose request type is existing PDU session to AMF#2.
  • the fourth PDU session request message carries the information of the DNN and the information of the S-NSSAI, so as to request to restore the PDU session associated with the DNN and the S-NSSAI.
  • a lossless handover indication may be additionally carried in the session request.
  • AMF#2 determines that the UE is performing cross-private network handover according to the cross-private network HO indication, the request type of the existing PDU session, or the SNPN#1 ID.
  • S409 AMF#2 forwards the fourth PDU session request message and the cross-private network HO indication to SMF#2.
  • S411 SMF#2 (or AMF#2) sends a release request to RAN#1 to request RAN#1 to release the first PDU session.
  • SMF#2/AMF#2 can determine that a lossless handover needs to be performed according to the local configuration, thereby instructing RAN#1 to forward the buffered downlink data to the UPF #2.
  • SMF#2/AMF#2 may instruct RAN#1 to forward the buffered downlink data to UPF#2 before releasing the PDU session through the third information. Subsequently, the data from RAN#1 can be forwarded to the UE by UPF#2 through the new path.
  • S412 RAN#1 forwards the buffered UE data to UPF#2, and releases the resources of the first PDU session, where the data includes an end marker.
  • UPF#2 forwards the data message from RAN#1 on the new path, that is, the data message is forwarded on UPF#2 ⁇ ->RAN#2 ⁇ ->UE; if UPF#2 receives the SMF If the instruction to switch the path is used, before forwarding the new downlink data message, the message received from RAN#1, that is, the original path, needs to be forwarded first, until the end marker is received.
  • the core network can instruct the UE to adopt a roaming-based cross-private network handover to improve the cross-private network handover efficiency.
  • data lossless handover can be provided for the UE.
  • the communication method provided by the embodiment of the present application may include FIG. 14a and/or Or the steps shown in Figure 14b.
  • the home network here may be an HPLMN or a home SNPN (home SNPN, HSNPN).
  • FIG. 14a shows another communication method provided by the embodiment of the present application when the first network is HPLMN and the second network is SNPN#2. This method can be applied to the scenarios shown in Figures 7b/7c.
  • SNPN#2 can also be replaced by VPLMN#2 (ie, a VPLMN).
  • the method may include the following steps:
  • the UE registers at SNPN#1 and establishes a first PDU session, the anchor UPF of the first PDU session is UPF#3 in the HPLMN, and the anchor SMF of the PDU session is SMF#3 in the HPLMN.
  • the first PDU session may be associated with the first DNN and the first S-NSSAI.
  • the SNPN#1 and the HPLMN communicate with each other based on the roaming mode.
  • S602 SMF#1 and SMF#3 respectively send SMF registration messages to the UDM.
  • the registration message may include the UE ID, SNPN#1 ID, SMF#1 ID (or SMF#3 ID) and the ID of the first PDU session.
  • the UDM can be deployed on HPLMN.
  • S603 The UE moves to the target network SNPN#2, and the UE sends a first registration request message to AMF#2 in the SNPN#2, which carries the UE ID.
  • the first registration request message may carry a cross-private network HO indication.
  • the cross-private network HO indication is used to indicate that the purpose of AMF#2 registration is to perform cross-private network handover, rather than initial registration.
  • the HO indication can be registered for location update or a new cell.
  • AMF#2 determines that the UE is performing cross-private network handover according to the cross-private network HO instruction of the UE, and determines the handover method according to the interworking method between SNPN#2 and the HPLMN (based on non-roaming interworking or based on roaming interworking), such as determining the UE Switch according to roaming interworking or not according to roaming interworking and so on.
  • AMF#2 can determine the ID of the home network of the UE according to the UE ID (for example, a subscription permanent identifier (SUPI) or a user concealed identifier (SUCI)) in the first registration request message of the UE, It may be the network ID of HPLMN or the network ID of SNPN#2. At the same time, AMF#2 can obtain the network ID of SNPN#2 from the RAN, and then determines the intercommunication mode between SNPN#2 and HPLMN according to the ID of the home network.
  • SUPI subscription permanent identifier
  • SUCI user concealed identifier
  • AMF#2 sends a registration response message to the UE, which carries a handover mode indication (ie, the first information).
  • the handover mode indication may indicate that the SNPN#2 and the HPLMN communicate in a non-roaming manner.
  • the handover mode indication may instruct the UE that if the UE does not support N3IWF to HPLMN, eg, N3IWF configuration without HPLMN or connection to N3IWF is not supported, then the first PDU session to HPLMN should not be established after registering with SNPN#2.
  • the handover mode indication can also instruct UE: if UE supports N3IWF to HPLMN, for example, UE has N3IWF configuration of HPLMN or supports connection to N3IWF, then UE establishes connection to HPLMN.
  • the PDU session of the N3IWF triggers the process of switching the first PDU session from 3GPP to N3GPP through the PDU session, and deletes the SMF#1/UPF#1 of the first PDU session.
  • the handover mode indication may instruct SNPN#2 and HPLMN to support roaming-based interworking, or the handover mode indication may instruct the UE to resume the first PDU session as follows: AMF#2 touches Find the I-SMF/I-UPF switching process of the PDU session in the mechanism, select SMF#2/UPF#2 to replace the original SMF#1/UPF#1, and restore the PDU session.
  • the UE then executes one of S606-S608 according to the handover mode instruction.
  • a DNN and the first S-NSSAI so the PDU session of the N3GPP after the handover can be associated to the first DNN and the first S-NSSAI, and the SMF#1 and UPF#1 of the first PDU session are deleted.
  • the UE can send a fourth PDU session request message whose request type is existing PDU session to AMF#2, which carries the first DNN and the first S-NSSAI to request the resumption of the association PDU session to this DNN and S-NSSAI.
  • AMF#2 receives the fourth session request, it triggers the I-SMF/I-UPF switching process of the PDU session in the existing mechanism, and selects SMF#2/UPF#2 to replace the original SMF#1/UPF#1, The first PDU session is resumed.
  • the handover mode indication can be used to instruct the roaming-based interworking between SNPN#1 and SNPN#2, or to instruct the UE to initiate the handover procedure of the PDU session from SNPN#1 to SNPN#2 at SNPN#2.
  • the AMF in the SNPN#2 can instruct the UE to perform the PDU session switching, which improves the PDU session switching. effectiveness.
  • the HPLMN may be replaced by a home SNPN (home SNPN, HSNPN).
  • FIG. 14b shows another communication method provided by the embodiment of the present application when the first network is HPLMN and the second network is SNPN#2. This method can be applied to the scenarios shown in Figures 7b/7c.
  • SNPN#2 can also be replaced by VPLMN#2 (ie, a VPLMN).
  • the method may include the following steps:
  • the UE connects to the N3IWF of the HPLMN through SNPN#1, registers with the HPLMN through the N3WIF and establishes a first PDU session, the anchor UPF of the first PDU session is UPF#3 in the HPLMN, and the anchor SMF of the PDU session is SMF #3 in HPLMN.
  • the first PDU session may be associated with the first DNN and the first S-NSSAI.
  • SNPN#1 and HPLMN intercommunicate based on N3IWF.
  • SMF#3 sends an SMF registration message to the UDM.
  • the registration message may include the UE ID, the network ID of the HPLMN, the SMF#3 ID and the ID of the first PDU session.
  • the UDM can be deployed on HPLMN.
  • S703 The UE moves to the target network SNPN#2, and the UE sends a first registration request message to AMF#2 in the SNPN#2, which carries the UE ID.
  • the first registration request message may carry a cross-private network HO indication.
  • the cross-private network HO indication is used to indicate that the purpose of AMF#2 registration is to perform cross-private network handover, rather than initial registration.
  • the HO indication can be registered for location update or a new cell.
  • AMF#2 determines that the UE is performing cross-private network handover according to the cross-private network HO instruction of the UE, and determines the handover method according to the interworking method between SNPN#2 and the HPLMN (based on non-roaming sending interworking or based on roaming interworking), if determined The UE performs handover according to roaming interworking or not according to roaming interworking.
  • AMF#2 can determine the ID of the UE's home network according to the UE ID (such as SUPI or SUCI) in the first registration request message of the UE, and the ID of the home network may be the network ID of HPLMN, or the ID of SNPN#2 Network ID. At the same time, AMF#2 can obtain the network ID of SNPN#2 from the RAN, and then determines the intercommunication mode between SNPN#2 and HPLMN according to the ID of the home network.
  • the UE ID such as SUPI or SUCI
  • AMF#2 sends a registration response message to the UE, carrying a handover mode indication (ie, the first information).
  • the handover mode indication may indicate that the SNPN#2 and the HPLMN communicate in a non-roaming manner.
  • the handover mode indication may instruct the UE that if the UE does not support N3IWF to HPLMN, eg, N3IWF configuration without HPLMN or connection to N3IWF is not supported, then the first PDU session to HPLMN should not be established after registering with SNPN#2.
  • the handover mode indication can also instruct UE: if UE supports N3IWF to HPLMN, for example, UE has N3IWF configuration of HPLMN or supports connection to N3IWF, then UE establishes connection to HPLMN.
  • a PDU session of the N3IWF, through which a PDU session is established at the HPLMN through the N3GPP, and the PDU session is associated with the first DNN and the first S-NSSAI.
  • the handover mode indication may instruct SNPN#2 and HPLMN to support roaming-based interworking, or the handover mode indication may instruct the UE to resume the first PDU session as follows: AMF#2 touches The I-SMF/I-UPF insertion procedure of the PDU session in the mechanism is found, and the SMF#2 and/or UPF#2 in the SNPN#2 are newly inserted.
  • the UE then executes one of S706-S708 according to the handover mode instruction.
  • the UE may send a fourth PDU session request message whose request type is existing PDU session to AMF#2, which carries the first DNN and the first S-NSSAI to request The PDU session associated with this DNN and S-NSSAI is resumed.
  • AMF#2 After AMF#2 receives the fourth session request, it triggers the I-SMF/I-UPF insertion procedure of the PDU session in the existing mechanism, and newly inserts SMF#2 and/or UPF#2 in SNPN#2 for Handover the first PDU session from N3GPP to 3GPP.
  • the handover mode indication can be used to instruct the roaming-based interworking between SNPN#1 and SNPN#2, or to instruct the UE to initiate the handover procedure of the PDU session from SNPN#1 to SNPN#2 at SNPN#2.
  • the AMF in the SNPN#2 can instruct the UE to switch the PDU session to improve the PDU Session switching efficiency.
  • HPLMN in the above process may be replaced by the home SNPN.
  • another communication method provided by this embodiment of the present application may include the following steps:
  • S501 The UE establishes a first PDU session in the first network.
  • This first PDU session is associated with the DNN and the S-NSSAI.
  • S502 The UE sends a first registration request message to the first network device in the second network.
  • the first network device receives the first registration request message.
  • the first registration request message may be used to request registration to the second network.
  • the first network device is an AMF deployed in the second network.
  • the first registration request message may carry a cross-non-public network handover instruction, where the cross-non-public network handover instruction is used to instruct the terminal device to perform cross-non-public network handover.
  • S503 Establish a PDU session of the UE according to the first sequence, where the PDU session is associated with the DNN and the S-NSSAI.
  • the first order may indicate the respective execution orders of the third manner, the second manner and the first manner, wherein the third manner is prior to the second manner and the first manner, and the second manner is prior to the first manner.
  • the first sequence may only include the sequence of the third manner, the second manner and the first manner, and at this time, the terminal device no longer executes the manners not included in the first sequence to further improve handover efficiency.
  • the above-mentioned first order can indicate that the above-mentioned third method takes precedence over the second method, and the second method takes precedence over the first method, and the UE can establish a PDU session according to the third method in priority. PDU session, then it will not try to establish a PDU session through the second method and the first method; otherwise, if the PDU session associated with the DNN and the S-NSSAI cannot be established according to the third method, the UE may try to establish a PDU session according to the second method.
  • the UE can restore the PDU session through the third method, the second method and/or the first method in the first order, so as to improve the handover efficiency.
  • the first manner, the second manner and the third manner may be respectively an intercommunication manner between the first network and the second network.
  • the first manner, the second manner and the third manner are respectively a manner for the UE to establish a PDU session associated with the DNN and the S-NSSAI in an intercommunication manner between the first network and the second network.
  • the first manner may include a non-interworking handover manner.
  • the non-intercommunication switching mode can be used to realize the switching of the PDU session of the UE when the first network and the second network do not communicate with each other.
  • the non-interworking switching mode specifically includes that the terminal device sends a first PDU session request message to the first network device,
  • the first PDU session request message includes a request type information element whose value is initial request, the information of the DNN, and the information of the S-NSSAI.
  • the first manner may include a manner when the UE establishes a PDU session associated with the DNN and the S-NSSAI when the first network and the second network do not communicate with each other.
  • the second manner may include an N3IWF interworking switching manner, and the N3IWF interworking switching manner may be used to implement PDU session switching of the UE when the first network and the second network are interworking based on N3IWF.
  • the N3IWF interworking switching mode may include the following steps: the UE sends a second PDU session request message to the first network device, where the second PDU session request is used to request the establishment of a second PDU session, and the UE establishes a connection with the N3IWF through the second PDU session , the N3IWF belongs to the first network; the UE sends a second registration request message to the second network device through the connection, and the second registration request message is used to request to register in the first network by means of N3GPP, and the second network device belongs to the second network device.
  • the first network the UE sends a third PDU session request message to the second network device, where the third PDU session request message includes a request type information element whose value is the existing PDU session, the information of the DNN and the information of the S-NSSAI.
  • the second manner may include the manner in which the UE establishes a PDU session associated with the DNN and the S-NSSAI when the first network and the second network communicate based on the N3IWF.
  • the third manner may include a roaming interworking switching manner, and the roaming interworking switching manner may be used to implement PDU session switching of the UE during roaming-based interworking between the first network and the second network.
  • the roaming interworking switching mode may include the following steps: the terminal device sends a fourth PDU session request message to the first network device, where the fourth PDU session request message includes a request type information element whose value is the existing PDU session, the information of the DNN and all information on S-NSSAI.
  • the fourth PDU session request message may include a lossless handover indication to implement lossless handover. For specific steps, refer to FIG. 11 to FIG.
  • the third manner may include the manner in which the UE establishes a PDU session associated with the DNN and the S-NSSAI when the first network and the second network communicate with each other based on roaming.
  • the above third manner may be replaced by a roaming interworking handover manner, or may be referred to as a roaming interworking handover manner, for implementing PDU session handover of the UE during roaming interworking between the first network and the second network.
  • the PDU session associated with the DNN and the S-NSSAI can be restored through the roaming interworking handover method, and the second optimal solution can be restored to the DNN through the N3IWF interworking handover method.
  • the PDU session associated with the DNN and the S-NSSAI can be restored again through a non-interoperable handover mode, so as to improve the handover efficiency.
  • the first order may indicate that the above-mentioned third method takes precedence over the second method, and the second method takes precedence over the first method, and the UE may establish a PDU session preferentially according to the third method.
  • the PDU session of the S-NSSAI it will not try to establish the PDU session through the second method and the first method; otherwise, if the PDU session associated with the DNN and the S-NSSAI cannot be established according to the third method, the UE may try to establish the PDU session according to the third method.
  • the second method establishes a PDU session associated with the DNN and the S-NSSAI; if a PDU session associated with the DNN and the S-NSSAI cannot be established according to the second method, the UE may attempt to establish a PDU session associated with the DNN according to the first method and the S-NSSAI PDU session.
  • the first order may be determined by local configuration.
  • the first order may be indicated by the first network device.
  • the first network device sends the indication information of the first order to the UE.
  • the first order may be indicated by a second network device deployed in the first network.
  • the second network device sends the indication information of the first order to the UE.
  • the indication information of the first order here may include the respective priorities of the above first manner, the second manner and the third manner.
  • the indication information may carry the priority of the first mode, the priority of the second mode and the priority of the third mode.
  • the indication information may directly instruct the UE to execute in the order of the third manner, the second manner and the first manner.
  • the indication information may further include respective information of the first mode, the second mode and the third mode, so as to indicate the first mode, the second mode and the third mode.
  • the indication information indicates the intercommunication mode between the first network and the second network corresponding to the first mode, the second mode and the third mode respectively, for example, indicating that the first mode does not communicate between the first network and the second network , and instructing the second mode for the N3IWF-based interworking between the first network and the second network, and instructing the third mode for the roaming-based interworking between the first network and the second network.
  • the indication information may also indicate the respective switching modes of the first mode, the second mode and the third mode, for example, indicating that the first mode is the non-interworking switching mode, indicating that the second mode is the N3IWF interworking switching mode, and indicating the first mode is the N3IWF interworking switching mode.
  • the third mode is the roaming interworking switching mode.
  • the UE may also determine the first mode, the second mode and the third mode according to the local configuration, for example, the first mode is determined to be the non-interworking handover mode according to the local configuration, and the second mode is determined to be the N3IWF interworking handover mode according to the local configuration, and According to the local configuration, it is determined that the third mode is the roaming interworking switching mode.
  • the first network device and the second network device may indicate the order of execution of the first mode, the second mode, and the third mode in other ways.
  • the indication information includes the first mode, the second mode, and the third mode.
  • Respective information for example, the interworking modes corresponding to the first, second, and third modes, or the information about the corresponding PDU session establishment modes
  • the order of the interworking modes can represent the first mode, the second mode, and the The execution sequence of the third mode respectively.
  • this embodiment of the present application supports the UE to determine the recovery mode of the PDU session according to the following method:
  • the UE After the UE establishes a PDU session associated with the DNN and the S-NSSAI in the first network and the UE registers with the second network, if the UE receives the first information from the first network device deployed in the second network, the first For information, refer to the description of the first information in the embodiments of the present application, and the UE can establish a PDU session associated with the DNN and the S-NSSAI according to the first information; otherwise, if the UE does not receive a message from the second network the first information, the above-mentioned switching method can be performed in the order of the third mode, the second mode and the first mode to try to establish a PDU session associated with the DNN and the S-NSSAI, wherein the sequence is implemented in this application.
  • the first order in the example.
  • the first order may be determined by the UE according to the local configuration, or according to the indication information of the first order from the second network device.
  • the present application further provides a communication device.
  • the communication apparatus can be used to implement the above functions of a session management network element, a user plane network element, a policy management network element, a terminal device or an access network element.
  • the communication device may include a hardware structure and/or a software module, and implement the above functions in the form of a hardware structure, a software module, or a hardware structure plus a software module. Whether one of the above functions is performed in the form of a hardware structure, a software module, or a hardware structure plus a software module depends on the specific application and design constraints of the technical solution.
  • a communication apparatus may include a communication module 1501 and a processing module 1502, and the above communication module 1501 and processing module 1502 are coupled to each other.
  • the communication apparatus 1500 can be used to execute the above shown in FIG. 3 to FIG. 8 by a terminal equipment (UE), a first network device (AMF #2 shown in FIG. 11 to FIG. 13 ) or SMF (or session management network element, For example, the steps performed by SMF#1 in Figures 11 and 12 or SMF#2 in Figure 13).
  • UE terminal equipment
  • AMF #2 shown in FIG. 11 to FIG. 13
  • SMF session management network element
  • the communication module 1501 can be used to support the communication device 1500 to communicate, and the communication module 1501 can also be referred to as a communication unit, a communication interface, a transceiver module or a transceiver unit.
  • the communication module 1501 may have a wireless communication function and/or a wired communication function.
  • the processing module 1502 may also be referred to as a processing unit, and may be configured to support the communication apparatus 1500 to perform the processing actions of the terminal device, the first network device or the SMF in the above method embodiments, including but not limited to: generating the information sent by the communication module 1501 , message, and/or demodulate and decode the signal received by the communication module 1501, and so on.
  • the communication module 1501 can establish a first PDU session associated with the DNN and the S-NSSAI in the first network, and the communication module 1501 can also report to the first network
  • the device sends a first registration request message, where the first registration request message is used to request registration to the second network.
  • the communication module 1501 may also receive first information from the first network device, where the first information is determined according to an intercommunication manner between the first network and the second network.
  • the communication module 1501 may further establish a PDU session according to the first information, and the PDU session is associated with the DNN and the S-NSSAI.
  • the first registration request message may include a cross-non-public network handover indication, which is used to instruct the communication device to perform cross-non-public network handover.
  • the above interworking manner between the first network and the second network includes non-interworking between the first network and the second network, interworking between the first network and the second network based on N3IWF, or all Roaming-based interworking between the first network and the second network.
  • the communication module 1501 may send a first PDU session request message to the first network device, the first PDU
  • the session request message includes a request type information element whose value is initial request, or in other words, the first PDU session request message is used to request the establishment of an initial PDU session.
  • the first PDU session request message includes the information of the DNN and the information of the S-NSSAI to request to establish a PDU session associated with the DNN and the S-NSSAI.
  • the UE can create a new PDU session associated with the DNN and the S-NSSAI in the second network to restore the PDU session associated with the DNN and the S-NSSAI, Improve switching efficiency.
  • the first information is used to indicate that the first network and the second network are not interoperable, or, The first information is used to instruct the communication apparatus to send the first PDU session request to the first network device. Accordingly, a flexible indication of the interworking manner can be realized.
  • the communication module 1501 may send a second PDU session request message to the first network device, the second PDU The session request is used to request the establishment of a second PDU session.
  • the communication module 1501 can also establish a connection with the N3IWF through the second PDU session, and the N3IWF belongs to the first network.
  • the communication module 1501 may also send a second registration request message to the second network device through the connection, where the second registration request message is used for requesting to register with the first network by means of N3GPP, and the second network device belongs to the first network.
  • the communication module 1501 may also send a third PDU session request message to the second network device, where the third PDU session request message includes a request type information element whose value is the existing PDU session, or in other words, the third PDU session request message is used to request Establish an existing PDU session.
  • the third PDU session request message may carry the information of the DNN and the information of the S-NSSAI.
  • the UE can establish the information associated with the DNN and the third PDU session of the S-NSSAI through the N3IWF and the second network device, so as to realize the association of the UE to the
  • the recovery of the PDU session of the DNN and the S-NSSAI improves the handover efficiency.
  • the first information may be used to indicate N3IWF-based interworking between the first network and the second network, or It is used for instructing to send the second PDU session request to the first network device, to send the second registration request to the second network device through the N3IWF, and to send the third PDU session request message to the second network device.
  • the communication module 1501 may send a fourth PDU session request message to the first network device, the fourth The PDU session request message includes the request type information element whose value is the existing PDU session, the information of the DNN, and the information of the S-NSSAI. Therefore, in the roaming-based intercommunication between the first network and the second network, the UE can establish the information associated with the DNN and the fourth PDU session of the S-NSSAI through the first network device, so as to realize the association of the UE with the DNN and the S-NSSAI. The recovery of the PDU session of S-NSSAI improves the handover efficiency.
  • the first information may be used to indicate roaming-based interworking between the first network and the second network, or It is used for instructing to send the fourth PDU session request message to the first network device.
  • the fourth PDU session request message includes a lossless handover indication. Therefore, in the case where the interworking mode includes roaming-based interworking between the first network and the second network, lossless network handover of the UE can be supported.
  • the communication module 1501 may receive a first registration request message from the terminal device, the communication device belongs to the second network, and the first registration request message for requesting registration to the second network.
  • the processing module 1502 may acquire the context of the terminal device, and determine that the terminal device has been registered with the first network according to the context.
  • the communication module 1501 may also send the first information to the terminal device according to the communication mode between the first network and the second network.
  • the processing module 1502 may further determine that the terminal device performs cross-non-public network handover according to the cross-non-public network handover indication included in the first registration request message, and the cross-non-public network handover indication is used to indicate the The terminal device performs cross-non-public network handover.
  • the processing module 1502 may determine that the terminal device performs cross-non-public network handover according to the identifier of the first network, and the identifier of the first network is included in the context.
  • the processing module 1502 may determine that the terminal device performs cross-non-public network handover according to the identifier of the second network device, and the identifier of the second network device is included in the context of the terminal device.
  • the second network device is a network device that the terminal device accesses when it registers with the first network, such as an AMF.
  • the communication module 1501 may receive the context of the terminal device from the second network device deployed in the first network.
  • the communication module 1501 can obtain the information of the second network device from the UDM, and request the context of the terminal device.
  • the communication module 1501 may receive the context of the terminal device from the data storage node, and the data storage node is shared by the first network and the second network.
  • the data storage node includes a UDM or AAA server.
  • the above interworking manner between the first network and the second network includes non-interworking between the first network and the second network, interworking between the first network and the second network based on N3IWF, or all Roaming-based interworking between the first network and the second network.
  • the first information may be used to indicate that the first network and the second network are not interoperable, or the first information It can be used to instruct the terminal device to send the first PDU session request message to the communication apparatus.
  • the first PDU session request message includes a request type information element whose value is initial request, or in other words, the first PDU session request message is used to request the establishment of an initial PDU session.
  • the first PDU session request message also includes the DNN (or DNN information) associated with the PDU session established by the terminal device on the first network and the S-NSSAI (or S-NSSAI information) associated with the PDU session, or , the first information is further used to instruct the UE to carry the information of the DNN associated with the PDU session established by the terminal device in the first network and the information of the S-NSSAI associated with the PDU session in the first PDU session request message.
  • the first information may be used to indicate N3IWF-based interworking between the first network and the second network.
  • the first information may be used to instruct the terminal device to send a second PDU session request message to the communication apparatus, to send a second registration request message to the second network device through the N3IWF, and to send a third PDU session request to the second network device information.
  • the second PDU session request message is used to request the establishment of a second PDU session, and the second PDU session is used to establish a connection between the terminal device and the N3IWF; the second registration request message is used to request the The N3GPP method is registered in the first network; the third PDU session request message includes a request type information element whose value is the existing PDU session, and the information of the DNN associated with the PDU session established by the terminal device in the first network. and the information of the S-NSSAI associated with the PDU session.
  • the first information may indicate roaming-based interworking between the first network and the second network.
  • the first information may instruct the terminal device to send a fourth PDU session request message to the communication apparatus, where the fourth PDU session request message includes a request type information element whose value is the existing PDU session, or in other words, the fourth PDU session request message uses upon request to establish an existing PDU session.
  • the fourth PDU session request message also includes the information of the DNN associated with the PDU session established by the terminal device on the first network and the information of the S-NSSAI associated with the PDU session.
  • the first information is also used to indicate the terminal device
  • the fourth PDU session request message carries the information of the DNN associated with the PDU session established by the terminal device on the first network and the information of the S-NSSAI associated with the PDU session.
  • the communication module 1501 may also receive the above-mentioned fourth PDU session request message from the terminal device.
  • the communication module 1501 may also send the fourth PDU session request message to the first SMF, where the first SMF is an intermediate SMF, the first SMF is connected to the second SMF, and the second SMF maintains the terminal device established on the first network
  • the first PDU session associated with the DNN and the S-NSSAI the first SMF can then forward the fourth PDU session request message to the second SMF, and the second SMF performs path switching.
  • the first SMF belongs to the first network, and the first SMF maintains the first PDU session established by the terminal device in the first network and associated with the DNN and the S-NSSAI.
  • the communication module 1501 may also send a cross-non-public network handover instruction to the first SMF, where the cross-non-public network handover instruction is used to instruct the terminal device to perform cross-non-public network handover.
  • the fourth PDU session request includes a lossless handover indication.
  • the processing module 1502 may establish a first PDU session associated with the DNN and the S-NSSAI for the end device registered with the first network.
  • the first PDU session is a PDU session between a first access network element and a first UPF, and the first access network element belongs to the first network.
  • the communication module 1501 may receive a fourth PDU session request message, where the fourth PDU session request message includes a request type information element whose value is an existing PDU session, or in other words, the fourth PDU session request message may be used to request the establishment of an existing PDU session.
  • the fourth PDU session request message further includes the information of the DNN and the information of the S-NSSAI to request to establish a PDU session associated with the DNN and the S-NSSAI.
  • the communication module 1501 may also send second information to the first UPF, where the second information is used to instruct the first UPF to send an end marker to the first access network element after the path switching of the first PDU session, and, for Instructing the first UPF to forward downlink data from the terminal device of the first access network element to the terminal device through the switched path, where the downlink data includes the end marker.
  • the communication module 1501 may also send third information to the first access network element, where the third information is used to instruct the first access network element to cache the downlink data of the terminal device by the first access network element Forward to the first UPF until the end marker is received and forwarded.
  • the fourth PDU session request message includes a lossless handover indication, or the processing module 1502 may determine to perform a lossless handover for the terminal device according to a local configuration.
  • the communication module 1501 may also receive a non-public network handover instruction.
  • the above fourth PDU request message comes from a first network device, and the first network device belongs to the second network.
  • the communication apparatus communicates with the second network, and the first network device communicates with the second network. device connection.
  • the fourth PDU session request message is sent by the first network device to the intermediate SMF, and forwarded by the intermediate SMF to the communication module 1501.
  • the communication device does not belong to the second network, and the first network device and the communication device There is no direct connection, and message forwarding is required through an intermediate SMF.
  • the communication module 1501 can establish a first PDU session associated with the DNN and the S-NSSAI in the first network, and the communication module 1501 can also send the first PDU to the first network device.
  • a registration request message is used to request registration to the second network.
  • the communication module 1501 may establish (or request to establish) a PDU session associated with the DNN and the S-NSSAI according to the first sequence.
  • the first sequence is used to indicate that the PDU session is established according to the third mode, the second mode and the first mode successively.
  • the processing module 1502 establishes (or requests to establish) the PDU session in the third manner, the second manner and the first manner through the communication module 1501 in the first order until the PDU session is established.
  • the first registration request message includes a cross-non-public network handover indication, where the cross-non-public network handover indication is used to instruct to perform cross-non-public network handover.
  • the communication module 1501 may send a first PDU session request message to the first network device, wherein the first PDU session request message includes a value of initial request The request type information element, or in other words, the first PDU session request message is used to request the establishment of an initial PDU session.
  • the first PDU session request message includes the information of the DNN and the information of the S-NSSAI to request to establish a PDU session associated with the DNN and the S-NSSAI.
  • the communication module 1501 may send a second PDU session request message to the first network device, where the second PDU session request is used to request to establish a second PDU session.
  • the communication module 1501 can establish a connection with the N3IWF, which belongs to the first network, through the second PDU session.
  • the communication module 1501 sends a second registration request message to the second network device through the connection, where the second registration request message is used to request to register with the first network in the N3GPP manner, and the second network device belongs to the first network.
  • the communication module 1501 may send a third PDU session request message to the second network device, where the third PDU session request message includes a request type information element with a value of existing PDU session, or , the third PDU session request message can be used to request the establishment of an existing PDU session.
  • the third PDU session request message may include the information of the DNN and the information of the S-NSSAI.
  • the communication module 1501 may send a fourth PDU session request message to the first network device, where the fourth PDU session request message includes a value of existing PDU session
  • the request type information element or in other words, the fourth PDU session request message may be used to request the establishment of an existing PDU session.
  • the fourth PDU session request message further includes the information of the DNN and the information of the S-NSSAI.
  • the fourth PDU session request message includes a lossless handover indication to support lossless handover.
  • the first order is determined according to a local configuration.
  • the communication module 1501 may receive the indication information of the first order from the first network device.
  • the indication information of the first order may be determined according to the local configuration of the first network device, or determined by the first network device according to an intercommunication manner between the first network and the second network.
  • the communication module 1501 may receive the indication information of the first order from the second network device.
  • the indication information of the first order may be determined according to the local configuration of the second network device, or determined by the second network device according to the intercommunication mode between the first network and the second network. Therefore, the first order can be determined flexibly.
  • the communication device 1600 may include a communication interface 1601 , a memory 1602 and a processor 1603 .
  • the communication interface 1601 can be used for communication by a communication device, such as for sending or receiving signals by wire and/or wireless, so as to send and/or receive information, data, and messages.
  • the memory 1602 is coupled to the processor 1603, and is used for storing programs and data necessary for the communication device 1600 to realize various functions.
  • the processor 1603 is configured to support the communication apparatus 1600 to perform the processing functions performed by the session management network element in the above method, such as determining to generate information, messages sent by the communication interface 1601, and/or performing processing on signals received by the communication interface 1601. Demodulation and decoding, etc.
  • the above memory 1602 and processor 1603 can be integrated into one body or independent of each other.
  • the communication interface 1601 may include a wired communication interface, which may be used to support the communication device 1600 to receive and send signaling and/or data in a wired manner.
  • the communication interface 1601 may also be referred to as a transceiver unit or a communication unit.
  • the communication interface 1601 may include a wireless transceiver (eg, including a modem and/or an antenna) that may be used to support the communication device 1600 to wirelessly receive and transmit signaling and/or data.
  • Communication interface 1601 may also be referred to as a wireless transceiver or wireless communication unit.
  • the processor 1603 can be implemented by a processing chip or a processing circuit.
  • the communication interface 1601 can establish a first PDU session associated with the DNN and the S-NSSAI in the first network, and the communication interface 1601 can also report to the first network
  • the device sends a first registration request message, where the first registration request message is used to request registration to the second network.
  • the communication interface 1601 may also receive first information from the first network device, where the first information is determined according to an intercommunication manner between the first network and the second network.
  • the communication interface 1601 can also establish a PDU session according to the first information, and the PDU session is associated with the DNN and the S-NSSAI.
  • the first registration request message may include a cross-non-public network handover indication, which is used to instruct the communication device to perform cross-non-public network handover.
  • the above interworking manner between the first network and the second network includes non-interworking between the first network and the second network, interworking between the first network and the second network based on N3IWF, or all Roaming-based interworking between the first network and the second network.
  • the communication interface 1601 may send a first PDU session request message to the first network device, the first PDU
  • the session request message includes a request type information element whose value is initial request, or in other words, the first PDU session request message is used to request the establishment of an initial PDU session.
  • the first PDU session request message includes the information of the DNN and the information of the S-NSSAI to request to establish a PDU session associated with the DNN and the S-NSSAI.
  • the UE can create a new PDU session associated with the DNN and the S-NSSAI in the second network to restore the PDU session associated with the DNN and the S-NSSAI, Improve switching efficiency.
  • the first information is used to indicate that the first network and the second network are not interoperable, or, The first information is used to instruct the communication apparatus to send the first PDU session request to the first network device. Accordingly, a flexible indication of the interworking manner can be realized.
  • the communication interface 1601 may send a second PDU session request message to the first network device, the second PDU The session request is used to request the establishment of a second PDU session.
  • the communication interface 1601 can also establish a connection with the N3IWF, which belongs to the first network, through the second PDU session.
  • the communication interface 1601 can also send a second registration request message to the second network device through the connection, where the second registration request message is used for requesting to register with the first network by means of N3GPP, and the second network device belongs to the first network.
  • the communication interface 1601 can also send a third PDU session request message to the second network device, where the third PDU session request message includes a request type information element whose value is the existing PDU session, or in other words, the third PDU session request message is used to request Establish an existing PDU session.
  • the third PDU session request message may carry the information of the DNN and the information of the S-NSSAI.
  • the UE can establish the information associated with the DNN and the third PDU session of the S-NSSAI through the N3IWF and the second network device, so as to realize the association of the UE to the
  • the recovery of the PDU session of the DNN and the S-NSSAI improves the handover efficiency.
  • the first information may be used to indicate N3IWF-based interworking between the first network and the second network, or It is used for instructing to send the second PDU session request to the first network device, to send the second registration request to the second network device through the N3IWF, and to send the third PDU session request message to the second network device.
  • the communication interface 1601 may send a fourth PDU session request message to the first network device, the fourth The PDU session request message includes the request type information element whose value is the existing PDU session, the information of the DNN, and the information of the S-NSSAI. Therefore, in the roaming-based intercommunication between the first network and the second network, the UE can establish the information associated with the DNN and the fourth PDU session of the S-NSSAI through the first network device, so as to realize the association of the UE with the DNN and the S-NSSAI. The recovery of the PDU session of S-NSSAI improves the handover efficiency.
  • the first information may be used to indicate roaming-based interworking between the first network and the second network, or It is used for instructing to send the fourth PDU session request message to the first network device.
  • the fourth PDU session request message includes a lossless handover indication. Therefore, in the case where the interworking manner includes roaming-based interworking between the first network and the second network, lossless network handover of the UE can be supported.
  • the communication interface 1601 may receive a first registration request message from the terminal device, the communication device belongs to the second network, and the first registration request message for requesting registration to the second network.
  • the processor 1603 may acquire the context of the terminal device, and determine according to the context that the terminal device has been registered with the first network.
  • the communication interface 1601 can also send the first information to the terminal device according to the communication mode between the first network and the second network.
  • the processor 1603 may further determine that the terminal device performs cross-non-public network handover according to the cross-non-public network handover indication included in the first registration request message, and the cross-non-public network handover indication is used to indicate the The terminal device performs cross-non-public network handover.
  • the processor 1603 may determine that the terminal device performs cross-non-public network handover according to the identifier of the first network, and the identifier of the first network is included in the context.
  • the processor 1603 may determine that the terminal device performs cross-non-public network handover according to the identifier of the second network device, and the identifier of the second network device is included in the context of the terminal device.
  • the second network device is a network device that the terminal device accesses when it registers with the first network, such as an AMF.
  • the communication interface 1601 may receive the context of the terminal device from the second network device deployed in the first network.
  • the communication interface 1601 can obtain the information of the second network device from the UDM, and request the context of the terminal device.
  • the communication interface 1601 may receive a context of a terminal device from a data storage node shared by the first network and the second network.
  • the data storage node includes a UDM or AAA server.
  • the above interworking manner between the first network and the second network includes non-interworking between the first network and the second network, interworking between the first network and the second network based on N3IWF, or all Roaming-based interworking between the first network and the second network.
  • the first information may be used to indicate that the first network and the second network are not interoperable, or the first information It can be used to instruct the terminal device to send the first PDU session request message to the communication apparatus.
  • the first PDU session request message includes a request type information element whose value is initial request, or in other words, the first PDU session request message is used to request the establishment of an initial PDU session.
  • the first PDU session request message also includes the DNN (or DNN information) associated with the PDU session established by the terminal device on the first network and the S-NSSAI (or S-NSSAI information) associated with the PDU session, or , the first information is further used to instruct the UE to carry the information of the DNN associated with the PDU session established by the terminal device in the first network and the information of the S-NSSAI associated with the PDU session in the first PDU session request message.
  • the first information may be used to indicate N3IWF-based interworking between the first network and the second network.
  • the first information may be used to instruct the terminal device to send a second PDU session request message to the communication apparatus, to send a second registration request message to the second network device through the N3IWF, and to send a third PDU session request to the second network device information.
  • the second PDU session request message is used to request the establishment of a second PDU session, and the second PDU session is used to establish a connection between the terminal device and the N3IWF; the second registration request message is used to request the The N3GPP method is registered in the first network; the third PDU session request message includes a request type information element whose value is the existing PDU session, and the information of the DNN associated with the PDU session established by the terminal device in the first network. and the information of the S-NSSAI associated with the PDU session.
  • the first information may indicate roaming-based interworking between the first network and the second network.
  • the first information may instruct the terminal device to send a fourth PDU session request message to the communication apparatus, where the fourth PDU session request message includes a request type information element whose value is the existing PDU session, or in other words, the fourth PDU session request message uses upon request to establish an existing PDU session.
  • the fourth PDU session request message also includes the information of the DNN associated with the PDU session established by the terminal device on the first network and the information of the S-NSSAI associated with the PDU session.
  • the first information is also used to indicate the terminal device
  • the fourth PDU session request message carries the information of the DNN associated with the PDU session established by the terminal device on the first network and the information of the S-NSSAI associated with the PDU session.
  • the communication interface 1601 may also receive the above-mentioned fourth PDU session request message from the terminal device.
  • the communication interface 1601 may also send the fourth PDU session request message to the first SMF, where the first SMF is an intermediate SMF, the first SMF is connected to the second SMF, and the second SMF maintains the terminal device established on the first network
  • the first PDU session associated with the DNN and the S-NSSAI the first SMF can then forward the fourth PDU session request message to the second SMF, and the second SMF performs path switching.
  • the first SMF belongs to the first network, and the first SMF maintains the first PDU session established by the terminal device in the first network and associated with the DNN and the S-NSSAI.
  • the communication interface 1601 may also send a cross-non-public network handover instruction to the first SMF, where the cross-non-public network handover instruction is used to instruct the terminal device to perform cross-non-public network handover.
  • the fourth PDU session request includes a lossless handover indication.
  • the processor 1603 may establish a first PDU session associated with the DNN and the S-NSSAI for the terminal device registered with the first network.
  • the first PDU session is a PDU session between a first access network element and a first UPF, and the first access network element belongs to the first network.
  • the communication interface 1601 may receive a fourth PDU session request message, where the fourth PDU session request message includes a request type information element whose value is an existing PDU session, or in other words, the fourth PDU session request message may be used to request the establishment of an existing PDU session.
  • the fourth PDU session request message also includes the information of the DNN and the information of the S-NSSAI to request the establishment of a PDU session associated with the DNN and the S-NSSAI.
  • the communication interface 1601 may also send second information to the first UPF, where the second information is used to instruct the first UPF to send an end marker to the first access network element after the path switching of the first PDU session, and, for Instructing the first UPF to forward downlink data from the terminal device of the first access network element to the terminal device through the switched path, where the downlink data includes the end marker.
  • the communication interface 1601 may also send third information to the first access network element, where the third information is used to instruct the first access network element to cache the downlink data of the terminal device by the first access network element Forward to the first UPF until the end marker is received and forwarded.
  • the fourth PDU session request message includes a lossless handover indication, or the processor 1603 may determine to perform a lossless handover for the terminal device according to a local configuration.
  • the communication interface 1601 may also receive a non-public network handover instruction.
  • the above fourth PDU request message comes from a first network device, and the first network device belongs to the second network.
  • the communication apparatus communicates with the second network, and the first network device communicates with the second network. device connection.
  • the fourth PDU session request message is sent by the first network device to the intermediate SMF, and forwarded by the intermediate SMF to the communication interface 1601.
  • the communication device does not belong to the second network, and the first network device and the communication device There is no direct connection, and message forwarding is required through an intermediate SMF.
  • the communication interface 1601 can establish a first PDU session associated with the DNN and the S-NSSAI in the first network, and the communication interface 1601 can also send the first PDU to the first network device.
  • a registration request message is used to request registration to the second network.
  • the communication interface 1601 may establish (or request to establish) a PDU session associated with the DNN and the S-NSSAI according to the first order.
  • the first sequence is used to indicate that the PDU session is established according to the third mode, the second mode and the first mode successively.
  • the processor 1603 establishes (or requests to establish) the PDU session through the communication interface 1601 in the third manner, the second manner and the first manner according to the first order, until the PDU session is established.
  • the first registration request message includes a cross-non-public network handover indication, where the cross-non-public network handover indication is used to instruct to perform cross-non-public network handover.
  • the communication interface 1601 may send a first PDU session request message to the first network device, wherein the first PDU session request message includes a value of initial request The request type information element, or in other words, the first PDU session request message is used to request the establishment of an initial PDU session.
  • the first PDU session request message includes the information of the DNN and the information of the S-NSSAI to request to establish a PDU session associated with the DNN and the S-NSSAI.
  • the communication interface 1601 may send a second PDU session request message to the first network device, where the second PDU session request is used to request the establishment of the second PDU session.
  • the communication interface 1601 can establish a connection with the N3IWF, which belongs to the first network, through the second PDU session.
  • the communication interface 1601 sends a second registration request message to the second network device through the connection, where the second registration request message is used to request to register with the first network in the N3GPP manner, and the second network device belongs to the first network.
  • the communication interface 1601 may send a third PDU session request message to the second network device, where the third PDU session request message includes a request type information element with a value of existing PDU session, or in other words , the third PDU session request message can be used to request the establishment of an existing PDU session.
  • the third PDU session request message may include the information of the DNN and the information of the S-NSSAI.
  • the communication interface 1601 may send a fourth PDU session request message to the first network device, where the fourth PDU session request message includes a value of existing PDU session
  • the request type information element or in other words, the fourth PDU session request message may be used to request the establishment of an existing PDU session.
  • the fourth PDU session request message further includes the information of the DNN and the information of the S-NSSAI.
  • the fourth PDU session request message includes a lossless handover indication to support lossless handover.
  • the first order is determined according to a local configuration.
  • the communication interface 1601 may receive the indication information of the first order from the first network device.
  • the indication information of the first order may be determined according to the local configuration of the first network device, or determined by the first network device according to an intercommunication manner between the first network and the second network.
  • the communication interface 1601 may receive the indication information of the first order from the second network device.
  • the indication information of the first order may be determined according to the local configuration of the second network device, or determined by the second network device according to the intercommunication mode between the first network and the second network. Therefore, the first order can be determined flexibly.
  • the embodiments of the present application further provide a computer-readable storage medium, on which a computer program (or instruction) is stored, and when the program is executed by a processor, the computer executes the above method.
  • a computer program or instruction
  • the operation performed by the terminal device, the first network device and/or the SMF in any possible implementation manner of the embodiment and the method embodiment.
  • the present application also provides a computer program product, which, when invoked and executed by a computer, can enable the computer to implement the above method embodiments and any possible implementation manner of the method embodiments. operations performed by the terminal device, the first network device and/or the SMF in the .
  • the present application further provides a chip or a chip system, the chip is coupled with a transceiver, and is used to realize the above method embodiments and any possible implementation manners of the method embodiments by a terminal device , an operation performed by the first network device and/or the SMF.
  • the chip system may include the chip, and components including a memory, a communication interface, and the like.
  • the present application further provides a communication system, which can be used to implement the foregoing method embodiments and any possible implementation manners of the method embodiments by consisting of a terminal device, a first network device and a / or the operation performed by the SMF.
  • the communication system has a structure as shown in any of FIG. 6 to FIG. 9 .
  • the communication system may be used to perform the flow as shown in any of Figures 10 to 14c.
  • the embodiments of the present application may be provided as a method, a system, or a computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.
  • computer-usable storage media including, but not limited to, disk storage, CD-ROM, optical storage, etc.
  • These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory result in an article of manufacture comprising instruction means, the instructions
  • the apparatus implements the functions specified in the flow or flow of the flowcharts and/or the block or blocks of the block diagrams.

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Abstract

本申请提供一种通信方法及装置，使得注册于第一网络的该终端设备可在第一网络建立关联到DNN和S-NSSAI的第一PDU会话，该终端设备还可向第一网络设备发送第一注册请求消息，该第一注册请求消息用于请求注册至第二网络。该终端设备还可接收来自于该第一网络设备的第一信息，该第一信息根据第一网络与该第二网络之间的互通方式确定。该终端设备还可根据该第一信息建立该终端设备的PDU会话，该PDU会话与该DNN和该S-NSSAI关联，能够提高UE在非公网进行切换的效率。

Description

一种通信方法及装置
相关申请的交叉引用
本申请要求在2020年08月12日提交中国专利局、申请号为202010808903.8、申请名称为“一种通信方法及装置”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；本申请要求在2020年09月30日提交中国专利局、申请号为202011066441.3、申请名称为“一种通信方法及装置”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
本申请涉及移动通信技术领域，尤其涉及一种通信方法及装置。
背景技术
在第五代(5th generation,5G)无线通信系统中，支持非公共网络(non-public network，NPN)作为非公用的5G网络。其中，NPN包括公共陆地移动网络(public land mobile network，PLMN)支持下实现的公网集成NPN(public network integrated NPN，PNI-NPN)和可不依赖于PLMN实现的独立部署NPN(standalone NPN，SNPN)。
另外，目前有两种方式支持PLMN与SNPN之间互通。例如图1所示，可通过非第三代合作伙伴计划(non 3rd generation partnership project，non-3GPP)互通功能网元(interworking function，N3IWF)实现PLMN与SNPN之间的互通。或者，可通过如图2所示的漫游架构实现PLMN与SNPN之间的互通。当然，两种方式也支持SNPN与SNPN之间互通。
因此，目前网络在支持一个SNPN与其他SNPN或PLMN之间互通时有如下几种可能：不互通、基于N3IWF架构的互通，以及基于漫游架构的互通。由于互通模式的区别，UE在两个网络之间移动时，如SNPN与PLMN之间或两个SNPN之间，UE进行切换的方式不同，但UE不能获知当前网络支持的互通模式，无法合理选择切换方式，导致UE在两个网络之间进行切换的切换效率不高或无法正确切换以保持业务连续性。
发明内容
本申请提供一种通信方法及装置，用以解决UE在跨NPN网络之间的切换效率不高或无法正确切换的问题。
第一方面，本申请实施例提供一种通信方法，该方法可由终端设备或终端设备的组件(如芯片、电路等组成部分)实施。终端设备可以是UE。
下面以执行主体为终端设备为例，根据该方法，注册于第一网络的该终端设备可在第一网络建立关联到数据网络名称(data network name，DNN)和单个网络切片选择辅助信息(single network slice selection assistance information，S-NSSAI)的第一协议数据单元(protocol data unit，PDU)会话，该终端设备还可向第一网络设备发送第一注册请求消息。该第一消息用于请求注册至第二网络，下面以第一消息为第一注册请求消息为例进行说明， 但不应理解为第一消息以注册请求为限。该终端设备还可接收来自于该第一网络设备的第一信息，该第一信息根据第一网络与该第二网络之间的互通方式确定。该终端设备还可根据该第一信息建立该终端设备的PDU会话，该PDU会话与该DNN和该S-NSSAI关联。
采用该方法，在从第一网络注册至第二网络后，UE可接收来自于第二网络中的第一网络设备的第一信息，由于第一信息与第一网络和第二网络之间的互通方式相关，根据第一信息能够更为高效地恢复UE的关联至DNN和S-NSSAI的PDU会话，以提高切换效率，确保业务连续性。
在一种可能的设计中，该第一注册请求消息中可包括跨非公网切换指示，用于指示该终端设备进行跨非公网切换。
在一种可能的设计中，以上第一网络与第二网络之间的互通方式包括第一网络与第二网络之间不互通、第一网络与第二网络之间基于N3IWF互通，或者，所述第一网络与所述第二网络之间基于漫游互通。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间不互通的情况下，终端设备可向该第一网络设备发送第二消息，该第二消息包括值为初始请求(initial request)的请求类型(request type)信元，或者说，第二消息用于请求建立初始PDU会话。下面以第二消息为第一PDU会话请求消息为例进行说明，但不应理解为第二消息以PDU会话请求消息为限。该第一PDU会话请求消息可包括该DNN的信息以及该S-NSSAI的信息，以请求建立关联至该DNN和该S-NSSAI的PDU会话。据此，在第一网络和第二网络不互通的方式下，UE可在第二网络新建关联至DNN和S-NSSAI的PDU会话，实现关联至该DNN和S-NSSAI的PDU会话的恢复，提高切换效率。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间不互通的情况下，该第一信息用于指示该第一网络与该第二网络之间不互通，或者，该第一信息用于指示该终端设备向该第一网络设备发送所述第一PDU会话请求。据此，可实现互通方式的灵活指示。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于N3IWF互通的情况下，终端设备可向第一网络设备发送第三消息，该第三消息用于请求建立第二PDU会话。下面以第三消息为第二PDU会话请求消息为例进行说明，但不应理解为第三消息以PDU会话请求消息为限。终端设备还可通过第二PDU会话建立与N3IWF的连接，该N3IWF属于所述第一网络。终端设备还可通过连接向第二网络设备发送第四消息，该第四消息用于请求通过N3GPP方式在第一网络注册，该第二网络设备属于该第一网络。下面以该第四消息为第二注册请求消息为例进行说明，但不应理解为第四消息以注册请求消息为限。终端设备还可向第二网络设备发送第五消息，该第五消息包括值为已有PDU会话(existing PDU session)的request type信元，或者说，第五消息用于请求建立已有PDU会话。下面以第五消息为第三PDU会话请求消息为例进行说明，但不应理解为第五消息以PDU会话请求消息为限。该第三PDU会话请求消息可携带该DNN的信息以及该S-NSSAI的信息。据此，在第一网络和第二网络基于N3IWF互通的方式下，UE可通过N3IWF和第二网络设备建立关联至该DNN的信息以及该S-NSSAI的第三PDU会话，实现UE的关联至该DNN和S-NSSAI的PDU会话的恢复，提高切换效率。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于N3IWF互通的情况下，第一信息可用于指示该第一网络与该第二网络之间基于N3IWF互通，或者用于 指示终端设备向该第一网络设备发送该第二PDU会话请求、通过该N3IWF向该第二网络设备发送该第二注册请求，以及向该第二网络设备发送该第三PDU会话请求消息。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于漫游互通的情况下，该终端设备可向该第一网络设备发送第六消息，该第六消息包括值为existing PDU session的request type信元、该DNN的信息以及该S-NSSAI的信息。下面以第六消息为第四PDU会话请求消息为例进行说明，但不应理解为第六消息以PDU会话请求消息为限。因此，在第一网络和第二网络基于漫游互通的方式下，UE可通过第一网络设备建立关联至该DNN的信息以及该S-NSSAI的第四PDU会话，实现UE的关联至该DNN和S-NSSAI的PDU会话的恢复，提高切换效率。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于漫游互通的情况下，该第一信息可用于指示第一网络与该第二网络之间基于漫游互通，或者用于指示终端设备向该第一网络设备发送该第四PDU会话请求消息。
在一种可能的设计中，该第四PDU会话请求消息中包括无损切换指示。因此，在互通方式包括第一网络与第二网络之间基于漫游互通的情况下，可支持UE的无损网络切换。
第二方面，本申请实施例提供一种通信方法，该方法可由第一网络设备或其组件执行。第一网络设备可包括核心网接入和移动性管理功能(core access and mobility management function，AMF)。
以第一网络设备为执行主体为例，根据该方法，第一网络设备可接收来自于终端设备的第一注册请求消息，该第一网络设备属于第二网络，该第一注册请求消息用于请求注册至所述第二网络。第一网络设备还可获取终端设备的上下文，并根据该上下文确定该终端设备已在第一网络注册。第一网络设备还可根据第一网络与第二网络之间的互通方式，向该终端设备发送第一信息。
在一种可能的设计中，第一网络设备可根据该第一注册请求消息包括的跨非公网切换指示确定该终端设备进行跨非公网切换，该跨非公网切换指示用于指示所述终端设备进行跨非公网切换。或者，第一网络设备可根据该第一网络的标识确定该终端设备进行跨非公网切换，该第一网络的标识包括在所述上下文中。或者，第一网络设备可根据该第二网络设备的标识确定该终端设备进行跨非公网切换，该第二网络设备的标识包括在终端设备的上下文中。第二网络设备为终端设备在第一网络注册时接入的网络设备，如AMF。
在一种可能的设计中，第一网络设备可接收来自于第二网络设备的终端设备的上下文，该第二网络设备部署于第一网络中。第一网络设备可从统一数据管理(unified data management，UDM)获取第二网络设备的信息，并请求该终端设备的上下文。
或者，第一网络设备接收来自于数据存储节点的终端设备的上下文，数据存储节点由第一网络以及第二网络共用。
在一种可能的设计中，该数据存储节点包括UDM或认证、授权、计费代理(authentication,authorization,accounting，AAA)服务器。
在一种可能的设计中，以上第一网络与第二网络之间的互通方式包括第一网络与第二网络之间不互通、第一网络与第二网络之间基于N3IWF互通，或者，所述第一网络与所述第二网络之间基于漫游互通。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间不互通的情况下，第一信息可用于指示第一网络与第二网络之间不互通，或者，第一信息可用于指示终端设备 向第一网络设备发送第一PDU会话请求消息。该第一PDU会话请求消息包括值为initial request的request type信元，或者说，第一PDU会话请求消息用于请求建立初始PDU会话。此外，第一PDU会话请求消息还包括终端设备在第一网络建立的PDU会话所关联的DNN(或DNN的信息)以及PDU会话所关联的S-NSSAI(或S-NSSAI的信息)，或者说，第一信息还用于指示UE在第一PDU会话请求消息中携带终端设备在第一网络建立的PDU会话所关联的DNN的信息以及PDU会话所关联的S-NSSAI的信息。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于N3IWF互通的情况下，第一信息可用于指示第一网络与第二网络之间基于N3IWF互通。或者，第一信息可用于指示终端设备向第一网络设备发送第二PDU会话请求消息、通过所述N3IWF向第二网络设备发送第二注册请求消息，以及向第二网络设备发送第三PDU会话请求消息。其中，第二PDU会话请求消息用于请求建立第二PDU会话，所述第二PDU会话用于建立所述终端设备与所述N3IWF之间的连接；所述第二注册请求消息用于请求通过N3GPP方式在所述第一网络注册；所述第三PDU会话请求消息包括值为existing PDU session的request type信元、所述终端设备在所述第一网络建立的PDU会话所关联的DNN的信息以及所述PDU会话所关联的S-NSSAI的信息。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于漫游互通的情况下，第一信息可指示第一网络与第二网络之间基于漫游互通。或者，第一信息可指示终端设备向第一网络设备发送第四PDU会话请求消息，该第四PDU会话请求消息包括值为existing PDU session的request type信元，或者说，第四PDU会话请求消息用于请求建立已有PDU会话。该第四PDU会话请求消息还包括终端设备在第一网络建立的PDU会话所关联的DNN的信息以及该PDU会话所关联的S-NSSAI的信息，或者说，第一信息还用于指示终端设备在第四PDU会话请求消息中携带终端设备在第一网络建立的PDU会话所关联的DNN的信息以及该PDU会话所关联的S-NSSAI的信息。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于漫游互通的情况下，第一网络设备还可接收来自于终端设备的上述第四PDU会话请求消息。第一网络设备还可向第一SMF发送所述第四PDU会话请求消息，其中，第一SMF为中间SMF，该第一SMF连接至第二SMF，该第二SMF维护终端设备在第一网络建立的关联至该DNN和该S-NSSAI的第一PDU会话，后续可由第一SMF将第四PDU会话请求消息转发至第二SMF，由第二SMF进行路径切换。或者，第一SMF属于第一网络，第一SMF维护终端设备在第一网络建立的关联至该DNN和该S-NSSAI的第一PDU会话。
在一种可能的设计中，第一网络设备还可向第一SMF发送跨非公网切换指示，所述跨非公网切换指示用于指示所述终端设备进行跨非公网切换。
在一种可能的设计中，该第四PDU会话请求中包括无损切换指示。
上述第二方面及其可能的设计中的有益效果可以参考对第一方面及其可能的设计中所述方法的有益效果的描述。
第三方面，本申请实施例提供一种通信方法，该方法可由终端设备或终端设备的组件(如芯片、电路等组成部分)实施。终端设备可以是UE。
下面以执行主体为终端设备为例，根据该方法，注册于第一网络的该终端设备可在第一网络建立关联到DNN和S-NSSAI的第一PDU会话，该终端设备还可向第一网络设备发送第一注册请求消息，该第一注册请求消息用于请求注册至第二网络。此外，终端设备根 据第一顺序建立(或请求建立)终端设备的PDU会话，该PDU会话与该第一PDU会话关联的DNN和S-NSSAI相关联，该PDU会话与该第一PDU会话关联的DNN和S-NSSAI相关联。其中，该第一顺序用于指示终端设备根据第三方式、第二方式和第一方式的先后顺序建立终端设备的PDU会话的先后顺序。或者说，终端设备按照第一顺序先后根据第三方式、第二方式和第一方式尝试建立终端设备的该PDU会话，直到建立该PDU会话。
比如，第一信息可指示第一方式、第二方式和第三方式分别的优先级，其中，第三方式的优先级最高，第二方式的优先级高于第一方式的优先级，则UE可按照优先级的高低先后执行第三方式、第二方式和第一方式，其中，如果按照某个方式成功建立该PDU会话，则终端设备不再按照优先级靠后的方式尝试建立该PDU会话。这里的成功建立该PDU会话，是指接收到网络侧的PDU会话建立响应消息，该PDU会话建立响应消息指示该PDU会话的成功建立。
采用以上流程，终端设备在从第一网络注册至第二网络后可按照第一顺序通过第一方式、第二方式和/或第三方式恢复PDU会话，以提高切换效率。
在一种可能的设计中，第一注册请求消息中包括跨非公网切换指示，该跨非公网切换指示用于指示所述终端设备进行跨非公网切换。
在一种可能的设计中，在根据第一方式建立所述终端设备的PDU会话时，终端设备可向第一网络设备发送第一PDU会话请求消息，其中，该第一PDU会话请求消息包括值为initial request的request type信元，或者说，第一PDU会话请求消息用于请求建立初始PDU会话。该第一PDU会话请求消息包括该DNN的信息以及该S-NSSAI的信息，以请求建立关联至该DNN和该S-NSSAI的PDU会话。
在一种可能的设计中，终端设备可向第一网络设备发送第二PDU会话请求消息，该第二PDU会话请求用于请求建立第二PDU会话。终端设备可通过第二PDU会话建立与N3IWF的连接，该N3IWF属于该第一网络。终端设备通过该连接向第二网络设备发送第二注册请求消息，该第二注册请求消息用于请求通过N3GPP方式在第一网络注册，该第二网络设备属于该第一网络。在按照第二方式建立该PDU会话时，终端设备可向第二网络设备发送第三PDU会话请求消息，该第三PDU会话请求消息包括值为existing PDU session的request type信元，或者说，该第三PDU会话请求消息可用于请求建立已有PDU会话。该第三PDU会话请求消息可包括该DNN的信息以及该S-NSSAI的信息。
在一种可能的设计中，在根据第三方式建立终端设备的PDU会话时，终端设备可向第一网络设备发送第四PDU会话请求消息，该第四PDU会话请求消息包括值为existing PDU session的request type信元，或者说，该第四PDU会话请求消息可用于请求建立已有PDU会话。该第四PDU会话请求消息还包括该DNN的信息以及该S-NSSAI的信息。因此，终端设备可优先通过第四PDU会话请求消息建立关联到该DNN和该S-NSSAI的PDU会话，提高切换效率。
在一种可能的设计中，所述第四PDU会话请求消息中包括无损切换指示，以支持无损切换。
在一种可能的设计中，所述第一顺序为根据本地配置确定的。或者，终端设备可接收来自于第一网络设备的第一顺序的指示信息。可选的，该第一顺序的指示信息可根据第一网络设备的本地配置确定，或由第一网络设备根据第一网络和第二网络之间的互通方式确定。或者，终端设备可接收来自于第二网络设备的第一顺序的指示信息。可选的，该第一 顺序的指示信息可根据第二网络设备的本地配置确定，或由第二网络设备根据第一网络和第二网络之间的互通方式确定。因此可灵活确定第一顺序。
在一种可能的设计中，第一注册请求消息中包括跨非公网切换指示，该跨非公网切换指示用于指示所述终端设备进行跨非公网切换。
第四方面，本申请实施例提供一种通信方法，该方法可由会话管理功能(session management function，SMF)或其组件执行。
下面以执行主体为SMF为例，根据该方法，SMF可建立终端设备的关联到DNN和S-NSSAI的第一PDU会话，该终端设备注册于第一网络。该第一PDU会话为第一接入网网元与第一UPF之间的PDU会话，该第一接入网网元属于该第一网络。SMF可接收第四PDU会话请求消息，该第四PDU会话请求消息包括值为existing PDU session的request type信元，或者说，该第四PDU会话请求消息可用于请求建立已有PDU会话。该第四PDU会话请求消息还包括该DNN的信息以及该S-NSSAI的信息，以请求建立关联至该DNN和该S-NSSAI的PDU会话。SMF还可向第一UPF发送第二信息，该第二信息用于指示第一UPF在第一PDU会话的路径切换后向该第一接入网网元发送结束标记，以及，用于指示该第一UPF将来自于该第一接入网网元的该终端设备的下行数据通过切换后的路径向该终端设备进行转发，该下行数据包括该结束标记。SMF还可向第一接入网网元发送第三信息，该第三信息用于指示该第一接入网网元将该第一接入网网元缓存的该终端设备的下行数据转发至该第一UPF，直到接收并转发该结束标记。
采用以上流程，可由SMF支持终端设备的无损路径切换以保持业务连续性。
在一种可能的设计中，该第四PDU会话请求消息包括无损切换指示，或者，可由SMF根据本地配置确定针对该终端设备执行无损切换。
在一种可能的设计中，SMF还可接收非公网切换指示。
在一种可能的设计中，以上第四PDU请求消息来自于第一网络设备，该第一网络设备属于第二网络，比如，此时该SMF与第二网络，第一网络设备与该SMF连接。或者，第四PDU会话请求消息由该第一网络设备发送至中间SMF，由中间SMF转发至该SMF，比如，此时SMF不属于第二网络，第一网络设备与SMF不直接连接，需要通过中间SMF进行消息转发。
第五方面，本申请实施例提供一种通信装置，可以实现上述第一方面、或第一方面任一种可能的实现方式中的方法。该装置包括用于执行上述方法的相应的单元或部件。该装置包括的单元可以通过软件和/或硬件方式实现。该装置例如可以为终端设备、或者为可支持终端设备实现上述方法的芯片、芯片系统、或处理器等。
在一个可能的设计中，所述通信装置的结构中可包括通信模块和处理模块等等，这些模块可以执行上述第一方面或第一方面的各个可能的设计示例中终端设备的相应功能。比如，通信模块可用于该通信装置执行信号、数据、信息或消息的接收和发送，处理模块可用于对通信模块接收的信号、数据、信息或消息进行处理，或用于生成由通信模块发送的信号、数据、信息或消息。
在执行上述第一方面所示方法时，该通信装置可注册于第一网络，该通信模块可在第一网络建立关联到DNN和S-NSSAI的第一PDU会话，该通信模块还可向第一网络设备发送第一注册请求消息，该第一注册请求消息用于请求注册至第二网络。该通信模块还可接收来自于该第一网络设备的第一信息，该第一信息根据第一网络与该第二网络之间的互通 方式确定。该通信模块还可根据该第一信息建立PDU会话，该PDU会话与该DNN和该S-NSSAI关联。
在一种可能的设计中，该第一注册请求消息中可包括跨非公网切换指示，用于指示该通信装置进行跨非公网切换。
在一种可能的设计中，以上第一网络与第二网络之间的互通方式包括第一网络与第二网络之间不互通、第一网络与第二网络之间基于N3IWF互通，或者，所述第一网络与所述第二网络之间基于漫游互通。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间不互通的情况下，该通信模块可向该第一网络设备发送第一PDU会话请求消息，该第一PDU会话请求消息包括值为initial request的request type信元，或者说，第一PDU会话请求消息用于请求建立初始PDU会话。该第一PDU会话请求消息包括该DNN的信息以及该S-NSSAI的信息，以请求建立关联至该DNN和该S-NSSAI的PDU会话。据此，在第一网络和第二网络不互通的方式下，UE可在第二网络新建关联至DNN和S-NSSAI的PDU会话，实现关联至该DNN和S-NSSAI的PDU会话的恢复，提高切换效率。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间不互通的情况下，该第一信息用于指示该第一网络与该第二网络之间不互通，或者，该第一信息用于指示该通信装置向该第一网络设备发送所述第一PDU会话请求。据此，可实现互通方式的灵活指示。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于N3IWF互通的情况下，该通信模块可向第一网络设备发送第二PDU会话请求消息，该第二PDU会话请求用于请求建立第二PDU会话。该通信模块还可通过第二PDU会话建立与N3IWF的连接，该N3IWF属于所述第一网络。该通信模块还可通过连接向第二网络设备发送第二注册请求消息，该第二注册请求消息用于请求通过N3GPP方式在第一网络注册，该第二网络设备属于该第一网络。该通信模块还可向第二网络设备发送第三PDU会话请求消息，该第三PDU会话请求消息包括值为existing PDU session的request type信元，或者说，第三PDU会话请求消息用于请求建立已有PDU会话。该第三PDU会话请求消息可携带该DNN的信息以及该S-NSSAI的信息。据此，在第一网络和第二网络基于N3IWF互通的方式下，UE可通过N3IWF和第二网络设备建立关联至该DNN的信息以及该S-NSSAI的第三PDU会话，实现UE的关联至该DNN和S-NSSAI的PDU会话的恢复，提高切换效率。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于N3IWF互通的情况下，第一信息可用于指示该第一网络与该第二网络之间基于N3IWF互通，或者用于指示向该第一网络设备发送该第二PDU会话请求、通过该N3IWF向该第二网络设备发送该第二注册请求，以及向该第二网络设备发送该第三PDU会话请求消息。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于漫游互通的情况下，该通信模块可向该第一网络设备发送第四PDU会话请求消息，该第四PDU会话请求消息包括值为existing PDU session的request type信元、该DNN的信息以及该S-NSSAI的信息。因此，在第一网络和第二网络基于漫游互通的方式下，UE可通过第一网络设备建立关联至该DNN的信息以及该S-NSSAI的第四PDU会话，实现UE的关联至该DNN和S-NSSAI的PDU会话的恢复，提高切换效率。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于漫游互通的情况 下，该第一信息可用于指示第一网络与该第二网络之间基于漫游互通，或者用于指示向该第一网络设备发送该第四PDU会话请求消息。
在一种可能的设计中，该第四PDU会话请求消息中包括无损切换指示。因此，在互通方式包括第一网络与第二网络之间基于漫游互通的情况下，可支持UE的无损网络切换。
另外，该通信装置的结构可包括处理器，可选的还包括通信接口(如收发器)和存储器。所述通信接口可用于收发信息或数据，以及用于该通信装置与网络系统中的其他通信装置(如第一网络设备)进行通信交互。所述处理器被配置为支持所述通信装置执行上述第一方面或第一方面的各个可能的设计示例中终端设备的相应的功能。所述存储器与所述处理器耦合，用于保存所述通信装置必要的程序指令和数据。示例性的，收发器可用于执行上述第五方面所述的通信模块所执行的步骤，处理器可用于执行上述第五方面所述的处理模块所执行的步骤。
上述第五方面及其可能的设计中的有益效果可以参考对第一方面及其可能的设计中所述方法的有益效果的描述。
第六方面，本申请实施例提供一种通信装置，可以实现上述第二方面、或第二方面任一种可能的实现方式中的方法。该装置包括用于执行上述方法的相应的单元或部件。该装置包括的单元可以通过软件和/或硬件方式实现。该装置例如可以为第一网络设备、或者为可支持第一网络设备实现上述第二方面、或第二方面任一种可能的方法的芯片、芯片系统、或处理器等。
在一个可能的设计中，所述通信装置的结构中可包括通信模块和处理模块等等，这些模块可以执行上述第二方面或第二方面的各个可能的设计示例中第一网络设备的相应功能。比如，通信模块可用于该通信装置执行信号、数据、信息或消息的接收和发送，处理模块可用于对通信模块接收的信号、数据、信息或消息进行处理，或用于生成由通信模块发送的信号、数据、信息或消息。
在执行上述第二方面所示方法时，通信模块可接收来自于终端设备的第一注册请求消息，该通信装置属于第二网络，该第一注册请求消息用于请求注册至所述第二网络。处理模块可获取终端设备的上下文，并根据该上下文确定该终端设备已在第一网络注册。通信模块还可根据第一网络与第二网络之间的互通方式，向该终端设备发送第一信息。
在一种可能的设计中，处理模块还可根据该第一注册请求消息包括的跨非公网切换指示确定该终端设备进行跨非公网切换，该跨非公网切换指示用于指示所述终端设备进行跨非公网切换。或者，处理模块可根据该第一网络的标识确定该终端设备进行跨非公网切换，该第一网络的标识包括在所述上下文中。或者，处理模块可根据该第二网络设备的标识确定该终端设备进行跨非公网切换，该第二网络设备的标识包括在终端设备的上下文中。第二网络设备为终端设备在第一网络注册时接入的网络设备，如AMF。
在一种可能的设计中，通信模块可接收来自于第二网络设备的终端设备的上下文，该第二网络设备部署于第一网络中。通信模块可从UDM获取第二网络设备的信息，并请求该终端设备的上下文。
或者，通信模块可接收来自于数据存储节点的终端设备的上下文，数据存储节点由第一网络以及第二网络共用。
在一种可能的设计中，该数据存储节点包括UDM或AAA服务器。
在一种可能的设计中，以上第一网络与第二网络之间的互通方式包括第一网络与第二 网络之间不互通、第一网络与第二网络之间基于N3IWF互通，或者，所述第一网络与所述第二网络之间基于漫游互通。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间不互通的情况下，第一信息可用于指示第一网络与第二网络之间不互通，或者，第一信息可用于指示终端设备向该通信装置发送第一PDU会话请求消息。该第一PDU会话请求消息包括值为initial request的request type信元，或者说，第一PDU会话请求消息用于请求建立初始PDU会话。此外，第一PDU会话请求消息还包括终端设备在第一网络建立的PDU会话所关联的DNN(或DNN的信息)以及PDU会话所关联的S-NSSAI(或S-NSSAI的信息)，或者说，第一信息还用于指示UE在第一PDU会话请求消息中携带终端设备在第一网络建立的PDU会话所关联的DNN的信息以及PDU会话所关联的S-NSSAI的信息。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于N3IWF互通的情况下，第一信息可用于指示第一网络与第二网络之间基于N3IWF互通。或者，第一信息可用于指示终端设备向该通信装置发送第二PDU会话请求消息、通过所述N3IWF向第二网络设备发送第二注册请求消息，以及向第二网络设备发送第三PDU会话请求消息。其中，第二PDU会话请求消息用于请求建立第二PDU会话，所述第二PDU会话用于建立所述终端设备与所述N3IWF之间的连接；所述第二注册请求消息用于请求通过N3GPP方式在所述第一网络注册；所述第三PDU会话请求消息包括值为existing PDU session的request type信元、所述终端设备在所述第一网络建立的PDU会话所关联的DNN的信息以及所述PDU会话所关联的S-NSSAI的信息。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于漫游互通的情况下，第一信息可指示第一网络与第二网络之间基于漫游互通。或者，第一信息可指示终端设备向该通信装置发送第四PDU会话请求消息，该第四PDU会话请求消息包括值为existing PDU session的request type信元，或者说，第四PDU会话请求消息用于请求建立已有PDU会话。该第四PDU会话请求消息还包括终端设备在第一网络建立的PDU会话所关联的DNN的信息以及该PDU会话所关联的S-NSSAI的信息，或者说，第一信息还用于指示终端设备在第四PDU会话请求消息中携带终端设备在第一网络建立的PDU会话所关联的DNN的信息以及该PDU会话所关联的S-NSSAI的信息。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于漫游互通的情况下，通信模块还可接收来自于终端设备的上述第四PDU会话请求消息。通信模块还可向第一SMF发送所述第四PDU会话请求消息，其中，第一SMF为中间SMF，该第一SMF连接至第二SMF，该第二SMF维护终端设备在第一网络建立的关联至该DNN和该S-NSSAI的第一PDU会话，后续可由第一SMF将第四PDU会话请求消息转发至第二SMF，由第二SMF进行路径切换。或者，第一SMF属于第一网络，第一SMF维护终端设备在第一网络建立的关联至该DNN和该S-NSSAI的第一PDU会话。
在一种可能的设计中，通信模块还可向第一SMF发送跨非公网切换指示，所述跨非公网切换指示用于指示所述终端设备进行跨非公网切换。
在一种可能的设计中，该第四PDU会话请求中包括无损切换指示。
另外，该通信装置的结构可包括处理器，可选的还包括通信接口(如有线通信接口等)和存储器。所述通信接口可用于收发信息或数据，以及用于该通信装置与网络系统中的其他通信装置(如终端设备等)进行通信交互。所述处理器被配置为支持所述通信装置执行 上述第二方面或第二方面的各个可能的设计示例中第一网络设备的相应的功能。所述存储器与所述处理器耦合，用于保存所述通信装置必要的程序指令和数据。示例性的，收发器可用于执行上述第六方面所述的通信模块所执行的步骤，处理器可用于执行上述第六方面所述的处理模块所执行的步骤。
上述第六方面及其可能的设计中的有益效果可以参考对第一方面及其可能的设计中所述方法的有益效果的描述。
第七方面，本申请实施例提供一种通信装置，可以实现上述第三方面、或第三方面任一种可能的实现方式中的方法。该装置包括用于执行上述方法的相应的单元或部件。该装置包括的单元可以通过软件和/或硬件方式实现。该装置例如可以为终端设备、或者为可支持终端设备实现上述方法的芯片、芯片系统、或处理器等。
在一个可能的设计中，所述通信装置的结构中可包括通信模块和处理模块等等，这些模块可以执行上述第三方面或第三方面的各个可能的设计示例中终端设备的相应功能。比如，通信模块可用于该通信装置执行信号、数据、信息或消息的接收和发送，处理模块可用于对通信模块接收的信号、数据、信息或消息进行处理，或用于生成由通信模块发送的信号、数据、信息或消息。
在执行上述第三方面所示方法时，该通信装置注册于第一网络，通信模块可在第一网络建立关联到DNN和S-NSSAI的第一PDU会话，该通信模块还可向第一网络设备发送第一注册请求消息，该第一注册请求消息用于请求注册至第二网络。此外，通信模块根据第一顺序建立PDU会话，该PDU会话与该DNN和该S-NSSAI关联。其中，该第一顺序用于指示先后根据第三方式、第二方式和第一方式建立该PDU会话。或者说，处理模块按照第一顺序，先后通过通信模块按照第三方式、第二方式和第一方式建立(或请求建立)PDU会话，直到建立该PDU会话。
在一种可能的设计中，第一注册请求消息中包括跨非公网切换指示，该跨非公网切换指示用于指示进行跨非公网切换。
在一种可能的设计中，在根据第一方式建立该PDU会话时，通信模块可向第一网络设备发送第一PDU会话请求消息，其中，该第一PDU会话请求消息包括值为initial request的request type信元，或者说，第一PDU会话请求消息用于请求建立初始PDU会话。该第一PDU会话请求消息包括该DNN的信息以及该S-NSSAI的信息，以请求建立关联至该DNN和该S-NSSAI的PDU会话。
在一种可能的设计中，通信模块可向第一网络设备发送第二PDU会话请求消息，该第二PDU会话请求用于请求建立第二PDU会话。通信模块可通过第二PDU会话建立与N3IWF的连接，该N3IWF属于该第一网络。通信模块通过该连接向第二网络设备发送第二注册请求消息，该第二注册请求消息用于请求通过N3GPP方式在第一网络注册，该第二网络设备属于该第一网络。在按照第二方式建立该PDU会话时，通信模块可向该第二网络设备发送第三PDU会话请求消息，该第三PDU会话请求消息包括值为existing PDU session的request type信元，或者说，该第三PDU会话请求消息可用于请求建立已有PDU会话。该第三PDU会话请求消息可包括该DNN的信息以及该S-NSSAI的信息。
在一种可能的设计中，在根据第三方式建立该PDU会话时，通信模块可向第一网络设备发送第四PDU会话请求消息，该第四PDU会话请求消息包括值为existing PDU session的request type信元，或者说，该第四PDU会话请求消息可用于请求建立已有PDU会话。 该第四PDU会话请求消息还包括该DNN的信息以及该S-NSSAI的信息。
在一种可能的设计中，所述第四PDU会话请求消息中包括无损切换指示，以支持无损切换。
在一种可能的设计中，所述第一顺序为根据本地配置确定的。或者，通信模块可接收来自于第一网络设备的第一顺序的指示信息。可选的，该第一顺序的指示信息可根据第一网络设备的本地配置确定，或由第一网络设备根据第一网络和第二网络之间的互通方式确定。或者，通信模块可接收来自于第二网络设备的第一顺序的指示信息。可选的，该第一顺序的指示信息可根据第二网络设备的本地配置确定，或由第二网络设备根据第一网络和第二网络之间的互通方式确定。因此可灵活确定第一顺序。
另外，该通信装置的结构可包括处理器，可选的还包括通信接口和存储器。所述通信接口可用于收发信息或数据，以及用于该通信装置与网络系统中的其他通信装置(如第一网络设备)进行通信交互。所述处理器被配置为支持所述通信装置执行上述第三方面或第三方面的各个可能的设计示例中终端设备的相应的功能。所述存储器与所述处理器耦合，用于保存所述通信装置必要的程序指令和数据。示例性的，收发器可用于执行上述第七方面所述的通信模块所执行的步骤，处理器可用于执行上述第七方面所述的处理模块所执行的步骤。
上述第七方面及其可能的设计中的有益效果可以参考对第三方面及其可能的设计中所述方法的有益效果的描述。
第八方面，本申请实施例提供一种通信装置，可以实现上述第四方面、或第四方面任一种可能的实现方式中的方法。该装置包括用于执行上述方法的相应的单元或部件。该装置包括的单元可以通过软件和/或硬件方式实现。该装置例如可以为SMF、或者为可支持SMF实现上述第四方面、或第四方面任一种可能的方法的芯片、芯片系统、或处理器等。
在一个可能的设计中，所述通信装置的结构中可包括通信模块和处理模块等等，这些模块可以执行上述第四方面或第四方面的各个可能的设计示例中SMF的相应功能。比如，通信模块可用于该通信装置执行信号、数据、信息或消息的接收和发送，处理模块可用于对通信模块接收的信号、数据、信息或消息进行处理，或用于生成由通信模块发送的信号、数据、信息或消息。
在执行上述第四方面所示方法时，处理模块可建立终端设备的关联到DNN和S-NSSAI的第一PDU会话，该终端设备注册于第一网络。该第一PDU会话为第一接入网网元与第一UPF之间的PDU会话，该第一接入网网元属于该第一网络。通信模块可接收第四PDU会话请求消息，该第四PDU会话请求消息包括值为existing PDU session的request type信元，或者说，该第四PDU会话请求消息可用于请求建立已有PDU会话。该第四PDU会话请求消息还包括该DNN的信息以及该S-NSSAI的信息，以请求建立关联至该DNN和该S-NSSAI的PDU会话。通信模块还可向第一UPF发送第二信息，该第二信息用于指示第一UPF在第一PDU会话的路径切换后向该第一接入网网元发送结束标记，以及，用于指示该第一UPF将来自于该第一接入网网元的该终端设备的下行数据通过切换后的路径向该终端设备进行转发，该下行数据包括该结束标记。通信模块还可向第一接入网网元发送第三信息，该第三信息用于指示该第一接入网网元将该第一接入网网元缓存的该终端设备的下行数据转发至该第一UPF，直到接收并转发该结束标记。
在一种可能的设计中，该第四PDU会话请求消息包括无损切换指示，或者，可由处 理模块根据本地配置确定针对该终端设备执行无损切换。
在一种可能的设计中，通信模块还可接收非公网切换指示。
在一种可能的设计中，以上第四PDU请求消息来自于第一网络设备，该第一网络设备属于第二网络，比如，此时该通信装置与第二网络，第一网络设备与该通信装置连接。或者，第四PDU会话请求消息由该第一网络设备发送至中间SMF，由中间SMF转发至该通信模块，比如，此时该通信装置不属于第二网络，第一网络设备与该通信装置不直接连接，需要通过中间SMF进行消息转发。
另外，该通信装置的结构可包括处理器，可选的还包括通信接口和存储器。所述通信接口可用于收发信息或数据，以及用于该通信装置与网络系统中的其他通信装置(如第一网络设备)进行通信交互。所述处理器被配置为支持所述通信装置执行上述第四方面或第四方面的各个可能的设计示例中SMF的相应的功能。所述存储器与所述处理器耦合，用于保存所述通信装置必要的程序指令和数据。示例性的，收发器可用于执行上述第八方面所述的通信模块所执行的步骤，处理器可用于执行上述第八方面所述的处理模块所执行的步骤。
上述第八方面及其可能的设计中的有益效果可以参考对第四方面及其可能的设计中所述方法的有益效果的描述。
第九方面，本申请实施例提供一种通信方法，该方法可由终端设备或终端设备的组件(如芯片、电路等组成部分)实施。终端设备可以是UE。
下面以执行主体为终端设备为例，根据该方法，注册于第一网络的终端设备在所述第一网络建立关联到DNN和S-NSSAI的第一PDU会话；所述终端设备向第一网络设备发送第一消息，所述第一消息用于请求注册至所述第二网络；所述终端设备接收来自于所述第一网络设备的第一信息，所述第一信息根据第一网络与所述第二网络之间的互通方式确定，所述第一网络与所述第二网络之间不漫游互通；所述终端设备根据所述第一信息，确定按照支持N3WIF的方式恢复所述终端设备的PDU会话，或确定不再建立所述终端设备的PDU会话，所述PDU会话与所述DNN和所述S-NSSAI关联。
采用该方法，可在第一网络与所述第二网络之间不漫游互通的情况，在终端设备移动到第二网络设备后实现终端设备的PDU会话的恢复，提高切换效率；或者终端设备不再建立PDU会话，以节省信令开销。
在一种可能的设计中，所述终端设备可向所述第一网络设备发送第三消息，所述第三消息用于请求建立第二PDU会话；所述终端设备通过所述第二PDU会话建立与N3IWF的连接，所述N3IWF属于所述第一网络；所述终端设备通过所述连接向第二网络设备发送第四消息，所述第四消息用于请求通过N3GPP方式在所述第一网络注册，所述第二网络设备属于所述第一网络；所述终端设备可向所述第二网络设备发送第五消息，所述第五消息用于请求建立已有PDU会话，所述第五消息包括所述DNN的信息以及所述S-NSSAI的信息。
在一种可能的设计中，所述第一信息用于指示所述第一网络与所述第二网络之间不支持不漫游互通。
第十方面，本申请实施例提供一种通信方法，该方法可由第一网络设备或其组件执行。第一网络设备可包括AMF。
根据该方法，第一网络设备可接收来自于终端设备的第一消息，所述第一网络设备属 于第二网络，所述第一消息用于请求注册至所述第二网络；所述第一网络设备获取终端设备的标识，确定第一网络的标识；所述第一网络设备根据第一网络与第二网络之间的漫游互通方式，向所述终端设备发送第一信息。
上述第十方面及其可能的设计中的有益效果可以参考对第九方面及其可能的设计中所述方法的有益效果的描述。
第十一方面，本申请实施例提供一种通信装置，可以实现上述第九方面、或第九方面任一种可能的实现方式中的方法。该装置包括用于执行上述方法的相应的单元或部件。该装置包括的单元可以通过软件和/或硬件方式实现。该装置例如可以为终端设备、或者为可支持终端设备实现上述方法的芯片、芯片系统、或处理器等。
在一个可能的设计中，所述通信装置的结构中可包括通信模块和处理模块等等，这些模块可以执行上述第一方面或第一方面的各个可能的设计示例中终端设备的相应功能。比如，通信模块可用于该通信装置执行信号、数据、信息或消息的接收和发送，处理模块可用于对通信模块接收的信号、数据、信息或消息进行处理，或用于生成由通信模块发送的信号、数据、信息或消息。
在执行上述第九方面所示方法时，注册于第一网络的终端设备通信模块在所述第一网络建立关联到DNN和S-NSSAI的第一PDU会话；通信模块向第一网络设备发送第一消息，所述第一消息用于请求注册至所述第二网络；通信模块接收来自于所述第一网络设备的第一信息，所述第一信息根据第一网络与所述第二网络之间的互通方式确定，所述第一网络与所述第二网络之间不漫游互通；处理模块根据所述第一信息，确定按照支持N3WIF的方式恢复PDU会话，或确定不再建立所述终端设备的PDU会话，所述PDU会话与所述DNN和所述S-NSSAI关联。
在一种可能的设计中，通信模块可用于向所述第一网络设备发送第三消息，所述第三消息用于请求建立第二PDU会话；通信模块通过所述第二PDU会话建立与N3IWF的连接，所述N3IWF属于所述第一网络；通信模块通过所述连接向第二网络设备发送第四消息，所述第四消息用于请求通过N3GPP方式在所述第一网络注册，所述第二网络设备属于所述第一网络；通信模块可向所述第二网络设备发送第五消息，所述第五消息用于请求建立已有PDU会话，所述第五消息包括所述DNN的信息以及所述S-NSSAI的信息。
在一种可能的设计中，所述第一信息用于指示所述第一网络不支持不漫游互通。
第十二方面，本申请实施例提供一种通信装置，可以实现上述第十方面、或第十方面任一种可能的实现方式中的方法。该装置包括用于执行上述方法的相应的单元或部件。该装置包括的单元可以通过软件和/或硬件方式实现。该装置例如可以为第一网络设备、或者为可支持第一网络设备实现上述第十方面、或第十方面任一种可能的方法的芯片、芯片系统、或处理器等。
在执行上述第十方面所示方法时，通信模块可接收来自于终端设备的第一消息，所述第一网络设备属于第二网络，所述第一消息用于请求注册至所述第二网络；所述第一网络设备获取终端设备的标识，确定第一网络的标识；通信模块根据第一网络与第二网络之间的漫游互通方式，向所述终端设备发送第一信息。
第十三方面，本申请实施例提供一种通信系统。该通信系统可包括以上第五方面提供的通信装置和第六方面提供的通信装置。
上述第十三方面及其可能的设计中的有益效果可以参考对第一方面及其可能的设计 中所述方法的有益效果的描述。
该通信系统还包括上述第八方面提供的通信装置。
当包括第八方面提供的通信装置的情况下，上述第十三方面及其可能的设计中的有益效果可以参考对第四方面及其可能的设计中所述方法的有益效果的描述。
该通信系统可包括以上第十一方面提供的通信装置和第十二方面提供的通信装置。
第十四方面，本申请实施例提供一种通信系统。该通信系统可包括以上第七方面提供的通信装置和第一网络设备。
上述第十方面及其可能的设计中的有益效果可以参考对第三方面及其可能的设计中所述方法的有益效果的描述。
该通信系统还包括上述第八方面提供的通信装置。
当包括第八方面提供的通信装置的情况下，上述第十方面及其可能的设计中的有益效果可以参考对第四方面及其可能的设计中所述方法的有益效果的描述。
第十五方面，本申请提供一种计算机存储介质，所述计算机存储介质中存储有程序或，当其在计算机上被调用执行时，使得计算机执行上述第一方面及其可能的设计、第二方面及其可能的设计、第三方面及其可能的设计，或第四方面及其可能的设计，或第九方面及其可能的设计，或第十方面及其可能的设计中任一所述的方法。
在执行上述第一方面及其可能的设计或第二方面及其可能的设计中任一所述的方法时，上述第十一方面及其可能的设计中的有益效果可以参考对第一方面及其可能的设计中所述方法的有益效果的描述。在执行上述第三方面及其可能的设计或第四方面及其可能的设计中任一所述的方法时，上述第十一方面及其可能的设计中的有益效果可以参考对第三方面及其可能的设计中所述方法的有益效果的描述。
第十六方面，本申请提供一种计算机程序产品，该计算基础产品可包含程序或指令，当所述计算机程序产品在计算机上运行时，使得计算机执行上述第一方面及其可能的设计、第二方面及其可能的设计、第三方面及其可能的设计，或第四方面及其可能的设计，或第九方面及其可能的设计，或第十方面及其可能的设计中任一所述的方法。
在执行上述第一方面及其可能的设计或第二方面及其可能的设计中任一所述的方法时，上述第十二方面及其可能的设计中的有益效果可以参考对第一方面及其可能的设计中所述方法的有益效果的描述。在执行上述第三方面及其可能的设计中任一所述的方法时，上述第十二方面及其可能的设计中的有益效果可以参考对第三方面及其可能的设计中所述方法的有益效果的描述。在执行上述第四方面及其可能的设计中任一所述的方法时，上述第十二方面及其可能的设计中的有益效果可以参考对第三方面及其可能的设计中所述方法的有益效果的描述。
第十三方面，本申请提供一种芯片或包含芯片的芯片系统(或称电路)，该芯片可包括处理器。该芯片还可以包括存储器(或存储模块)和/或收发器(或通信模块)。该芯片可用于执行上述第一方面及其可能的设计、第二方面及其可能的设计、第三方面及其可能的设计，或第四方面及其可能的设计，或第九方面及其可能的设计，或第十方面及其可能的设计中任一所述的方法。该芯片系统可以由上述芯片构成，也可以包含上述芯片和其他分立器件，如存储器(或存储模块)和/或收发器(或通信模块)。
在执行上述第一方面及其可能的设计或第二方面及其可能的设计中任一所述的方法时，上述第十二方面及其可能的设计中的有益效果可以参考对第一方面及其可能的设计中 所述方法的有益效果的描述。在执行上述第三方面及其可能的设计中任一所述的方法时，上述第十二方面及其可能的设计中的有益效果可以参考对第三方面及其可能的设计中所述方法的有益效果的描述。在执行上述第四方面及其可能的设计中任一所述的方法时，上述第十二方面及其可能的设计中的有益效果可以参考对第三方面及其可能的设计中所述方法的有益效果的描述。
第十方面，提供了一种通信系统，所述通信系统包括第一终端设备、第二终端设备、上述第三方面、第三方面任意一种可能的实现方式、上述第四方面和第四方面任意一种可能的实现方式所述的通信装置。
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图1为本申请实施例提供的一种通信系统的架构示意图；
图2为本申请实施例提供的另一种通信系统的架构示意图；
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图8为本申请实施例提供的另一种通信系统的架构示意图；
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图10为本申请实施例提供的一种通信方法的流程示意图；
图11为本申请实施例提供的另一种通信方法的流程示意图；
图12为本申请实施例提供的另一种通信方法的流程示意图；
图13为本申请实施例提供的另一种通信方法的流程示意图；
图14a为本申请实施例提供的另一种通信方法的流程示意图；
图14b为本申请实施例提供的另一种通信方法的流程示意图；
图14c为本申请实施例提供的另一种通信方法的流程示意图；
图15为本申请实施例提供的一种通信装置的结构示意图；
图16为本申请实施例提供的另一种通信装置的结构示意图。
具体实施方式
为了解决UE在跨SNPN网络之间的切换效率不高或无法正确切换的问题，本申请提供一种通信方法。下面将结合附图对本申请作进一步地详细描述。应理解，下面所介绍的方法实施例中的具体操作方法也可以应用于装置实施例或系统实施例中。
下一代(即5G)移动通信系统架构(next generation，NextGen/NG)，由UE(或称NextGen UE)、(无线)接入网((radio)access network，(R)AN/NextGen(R)AN)、核心网(core/NextGen core)和数据网络(data network，DN)构成，其中，UE、接入网和核心网是构成架构的主要成分，逻辑上它们可以分为用户面和控制面两部分，控制面负 责移动网络的管理，用户面负责业务数据的传输。其中，NG2参考点位于接入网控制面和核心网控制面之间，NG3参考点位于接入网用户面和核心网用户面之间，NG6参考点位于核心网用户面和数据网络之间。
应理解，本申请中，UE是移动用户与网络交互的入口，能够提供基本的计算能力，存储能力，向用户显示业务窗口，接受用户操作输入。NextGen UE会采用新空口技术，与AN建立信号连接、数据连接，从而传输控制信号和业务数据到移动网络。
接入网类似于传统网络里面的基站，部署在靠近UE的位置，为特定区域的授权用户提供入网功能，并能够根据用户的级别，业务的需求等确定不同质量的传输隧道来传输用户数据。AN能够管理自身的资源，合理利用，按需为UE提供接入服务，并负责把控制信号和用户数据在UE和核心网之间转发。
核心网负责维护移动网络的签约数据，管理移动网络的网元，为UE提供会话管理，移动性管理，策略管理，安全认证等功能。在UE附着的时候，为UE提供入网认证；在UE有业务请求时，为UE分配网络资源；在UE移动的时候，为UE更新网络资源；在UE空闲的时候，为UE提供快恢复机制；在UE去附着的时候，为UE释放网络资源；在UE有业务数据时，为UE提供数据路由功能，如转发上行数据到数据网络；或者从数据网络接收UE下行数据，转发到AN，从而发送给UE。
数据网络是为用户提供业务服务的网络，一般客户端位于UE，服务端位于数据网络。数据网络可以是私有网络，如局域网，也可以是不受运营商管控的外部网络，如因特网，还可以是运营商共同部署的专有网络，如提供互联网协议(internet protocol，IP)多媒体网络子系统(IP multimedia core network subsystem，IMS)服务的网络。
其中，UE是一种具有无线收发功能的设备，可以部署在陆地上，包括室内或室外、手持、穿戴或车载；也可以部署在水面上(如轮船等)；还可以部署在空中(例如飞机、气球和卫星上等。所述终端设备可以经无线接入网(radio access network，RAN)与核心网进行通信，与RAN交换语音和/或数据。所述终端设备可以是手机(mobile phone)、平板电脑(Pad)、带无线收发功能的电脑、移动互联网设备(mobile internet device，MID)、可穿戴设备、虚拟现实(virtual reality，VR)终端设备、增强现实(augmented reality，AR)终端设备、工业控制(industrial control)中的无线终端、无人驾驶(self driving)中的无线终端、远程医疗(remote medical)中的无线终端、智能电网(smart grid)中的无线终端、运输安全(transportation safety)中的无线终端、智慧城市(smart city)中的无线终端、智慧家庭(smart home)中的无线终端等等。本申请的实施例对应用场景不做限定。本申请的实施例对终端设备所采用的具体技术、设备形态以及名称不做限定。
接入网可包括接入网设备。接入网设备是网络中用于将终端设备接入到无线网络的设备。所述接入网设备可以为无线接入网中的节点，又可以称为基站，还可以称为无线接入网(radio access network，RAN)节点(或设备)。网络设备可以包括长期演进(long term evolution，LTE)系统或演进的LTE系统(LTE-Advanced，LTE-A)中的演进型基站(NodeB或eNB或e-NodeB，evolutional Node B)，如传统的宏基站eNB和异构网络场景下的微基站eNB，或者也可以包括第五代移动通信技术(5th generation，5G)新无线(new radio，NR)系统中的下一代节点B(next generation node B，gNB)，或者还可以包括无线网络控制器(radio network controller，RNC)、节点B(Node B，NB)、基站控制器(base station controller，BSC)、基站收发台(base transceiver station，BTS)、传输接收点(transmission  reception point，TRP)、家庭基站(例如，home evolved NodeB，或home Node B，HNB)、基带单元(base band unit，BBU)、基带池BBU pool，或WiFi接入点(access point，AP)等，再或者还可以包括云接入网(cloud radio access network，CloudRAN)系统中的集中式单元(centralized unit，CU)和分布式单元(distributed unit，DU)，本申请实施例并不限定。在接入网设备包括CU和DU的分离部署场景中，CU支持无线资源控制(radio resource control，RRC)、分组数据汇聚协议(packet data convergence protocol，PDCP)、业务数据适配协议(service data adaptation protocol，SDAP)等协议；DU主要支持无线链路控制层(radio link control，RLC)、媒体接入控制层(media access control，MAC)和物理层协议。
核心网可包括以下网元或节点：
接入管理网元(本申请实施例还可以称为接入移动管理网元)，主要用于移动网络中的终端的附着、移动性管理、跟踪区更新流程，接入管理网元终结了非接入层(non access stratum，NAS)消息、完成注册管理、连接管理以及可达性管理、分配跟踪区域列表(track area list，TA list)以及移动性管理等，并且透明路由会话管理(session management，SM)消息到会话管理网元。在第五代(5th generation，5G)通信系统中，接入管理网元可以是接入与移动性管理功能(access and mobility management function，AMF)，在未来的通信系统(如6G通信系统)中，移动性管理网元可以仍是AMF网元，或者也可以具有其它名称，本申请并不限定。
会话管理网元，主要用于移动网络中的会话管理，如会话建立、修改、释放。具体功能如为终端分配互联网协议(internet protocol，IP)地址、选择提供报文转发功能的用户面网元等。在5G通信系统中，会话管理网元可以是会话管理功能(session management function，SMF)，在未来的通信系统(如6G通信系统)中，会话管理网元可以仍是SMF网元，或者也可以具有其它名称，本申请并不限定。
用户面网元，主要用于对用户报文进行处理，如转发、计费、合法监听等。用户面网元也可以称为协议数据单元(protocol data unit，PDU)会话锚点(PDU session anchor，PSA)。在5G通信系统中，用户面网元可以是用户面功能(user plane function，UPF)，在未来的通信系统(如6G通信系统)中，用户面网元可以仍是UPF网元，或者也可以具有其它名称，本申请并不限定。
策略控制网元，包含用户签约数据管理功能、策略控制功能、计费策略控制功能、服务质量(quality of service，QoS)控制等。在5G通信系统中，策略控制网元可以是策略控制功能(policy control function，PCF)，在未来的通信系统(如6G通信系统)中，策略控制网元可以仍是PCF网元，或者也可以具有其它名称，本申请并不限定。
网络切片选择功能网元，主要用于为终端设备的业务选择合适的网络切片。在5G通信系统中，网络切片选择网元可以是网络切片选择功能(network slice selection function，NSSF)网元，在未来的通信系统(如6G通信系统)中，网络切片选择网元可以仍是NSSF网元，或者也可以具有其它名称，本申请并不限定。
网络存储功能网元，主要用于提供网元或网元所提供服务的注册和发现功能。在5G通信系统中，网络存储功能网元可以是网络仓库功能(network repository function，NRF)，在未来的通信系统(如6G通信系统)中，网络存储功能网元可以仍是NRF网元，或者也可以具有其它名称，本申请并不限定。
网络数据分析网元，可以从各个网络功能(network function，NF)，例如策略控制网 元、会话管理网元、用户面网元、接入管理网元、应用功能网元(通过网络能力开放功能网元)收集数据，并进行分析和预测。在5G通信系统中，网络数据分析网元可以是网络数据分析功能(network data analytics function，NWDAF)，在未来的通信系统(如6G通信系统)中，网络数据分析网元可以仍是NWDAF网元，或者也可以具有其它名称，本申请并不限定。
统一数据管理网元，主要用于管理终端设备的签约信息。在5G通信系统中，统一数据管理网元可以是统一数据管理(unified data management，UDM)，在未来的通信系统(如6G通信系统)中，统一数据管理网元可以仍是UDM网元，或者也可以具有其它名称，本申请并不限定。
统一数据存储网元，主要用于存储结构化的数据信息，其中包括签约信息、策略信息，以及有标准格式定义的网络数据或业务数据。在5G通信系统中，统一数据存储网元可以是统一数据存储(unified data repository，UDR)，在未来的通信系统(如6G通信系统)中，统一数据存储网元可以仍是UDR网元，或者也可以具有其它名称，本申请并不限定。
认证服务功能网元，主要用于对终端设备进行安全认证。在5G通信系统中，认证服务功能网元可以是认证服务器功能(authentication server function，AUSF)，在未来的通信系统(如6G通信系统)中，认证服务功能网元可以仍是AUSF网元，或者也可以具有其它名称，本申请并不限定。
网络能力开放网元，可以将网络的部分功能有控制地暴露给应用。在5G通信系统中，网络能力开放网元可以是网络能力开放功能(network exposure function，NEF)，在未来的通信系统(如6G通信系统)中，网络能力开放网元可以仍是NEF网元，或者也可以具有其它名称，本申请并不限定。
应用功能网元，可以向运营商的通信网络的控制面网元提供各类应用的服务数据，或者从通信网络的控制面网元获得网络的数据信息和控制信息。在5G通信系统中，应用功能网元可以是应用功能(application function，AF)，在未来的通信系统(如6G通信系统)中，应用功能网元可以仍是AF网元，或者也可以具有其它名称，本申请并不限定。
数据网络，主要用于为终端设备提供数据传输服务。数据网络可以是私有网络，如局域网，也可以是公用数据网(public data network，PDN)网络，如因特网(Internet)，还可以是运营商共同部署的专有网络，如配置的IP多媒体网络子系统(IP multimedia core network subsystem，IMS)服务。
应理解，上述网元或者功能既可以是硬件设备中的网络元件，也可以是在专用硬件上运行的软件功能，或者是平台(例如，云平台)上实例化的虚拟化功能。可选的，上述网元或者功能可以由一个设备实现，也可以由多个设备共同实现，还可以是一个设备内的一个功能模块，本申请实施例对此不作具体限定。
为方便说明，本申请后续，以接入管理网元为AMF网元，网络切片选择功能网元为NSSF网元，为例进行说明。进一步地，将AMF网元简称为AMF，NSSF网元简称为NSSF。即本申请后续所描述的AMF均可替换为接入管理网元，NSSFF均可替换为网络切片选择功能网元。
如图3所示，以5G架构为例，本申请实施例提供的通信系统用户面可包括用户面功能(user plane function，UPF)，核心网控制面可包括认证服务器功能(authentication server function，AUSF)、核心网接入和移动性管理功能(core access and mobility management  function，AMF)、会话管理功能(session management function，SMF)、网络切片选择功能(network slice selection function，NSSF)、网络开放功能(network exposure function，NEF)、网络功能仓储功能(network function repository function，NRF)、统一数据管理(unified data management，UDM)、策略控制功能(policy control function，PCF)和应用功能(application function，AF)。
如图3所示，核心网控制面采用服务化架构，控制面网元之间的交互采用服务调用的方式，来替换传统架构中的点对点通信方式。服务化架构中，控制面网元会向其他控制面网元开放服务，供其他控制面网元调用；点对点通信中，控制面网元之间通信接口会存在一套特定的消息，只能由接口两端的控制面网元在通信时使用。
示例性的，UPF可用于根据SMF的路由规则执行用户数据包转发，如将上行数据发送到DN或其他UPF，和/或将下行数据转发到其他UPF或者RAN。AUSF可用于执行UE的安全认证。AMF可用于UE的接入管理和移动性管理(mobility management，MM)，负责UE的状态维护，UE的可达性管理，非MM非接入层(non-access-stratum，NAS)消息的转发，SM N2消息的转发。SMF可用于UE会话管理，为UE的会话分配资源，释放资源；其中资源包括会话QoS，会话路径，转发规则等。NSSF可用于为UE选择网络切片。NEF可用于以北向应用编程接口(application programming interface，API)接口的方式向第三方开放网络功能。NRF可用于为其他网元提供网络功能实体信息的存储功能和选择功能。UDM可用于用户签约上下文(或称签约数据、UE上下文等)存储和管理。PCF可用于用户策略管理。AF可用于应用管理。
如图1和图2所示，目前的NPN网络包括PNI-NPN和SNPN。
其中，PNI-NPN可以使用PLMN中的网络切片实现，为了阻止非授权UE尝试接入和选择PNI-NPN，额外使用封闭访问组(closed access group，CAG)功能。CAG可用于识别一组用户，这些用户允许接入与CAG关联的小区(即CAG小区)。为了防止不允许接入CAG小区的UE自动选择和接入CAG小区，CAG小区广播一个或者多个CAG标识(identifier，ID)，UE上配置可用的CAG目录(list)和指示(用于指示UE是否只允许通过CAG小区接入5GS)，UDM上UE签约数据包括可用的CAG list和指示。
SNPN网络独立部署，不依赖PLMN网络，SNPN网络使用PLMN ID和网络标识(network identifier，NID)来标识，其中PLMN ID可以为第三方运营商预留的固有值，也可以是部署此SNPN的PLMN运营商的特定值。在SNPN网络中，其小区广播PLMN ID以及NID，UE根据广播信息和配置的选网信息选择接入的NPN网络。如果UE发现配置的选网信息包括的PLMN ID及NID1的组合与网络广播的PLMN ID或者PLMN ID与NID2的组合不相同，则UE不会选择其接入。
如图4所示，PNI-NPN通过广播CAG ID和配置UE可用的CAG ID限制UE的接入，SNPN则通过广播PLMN ID和NID让UE正确选择小区和网络。
如图1所示，目前R16支持SNPN与PLMN通过N3IWF架构互通，UE可分别签约到SNPN与PLMN。其中，UE可使用SNPN的私网签约选择SNPN ID，接入SNPN基站，在SNPN网络进行3GPP注册。以及，UE可使用PLMN的公网签约选择PLMN ID，选择PLMN N3IWF，在SNPN网络建立PDU会话接入PLMN N3IWF，在PLMN网络进行N3GPP注册。
如图2所示，R17下SNPN需要支持终端使用“外部签约”接入此SNPN网络，即终端 的用户签约为独立于SNPN网络的外部实体(如移动网络运营商(mobile network operator，MNO))所拥有，SNPN网络允许此类终端使用外部签约接入SNPN。例如，在UE接入SNPN网络时，SNPN网络实体(如AMF/SMF)需要与PLMN网络实体(如UDM/AUSF)交互，例如获取请求PLMN网络对UE进行鉴权认证，请求PLMN网络提供UE的签约信息，请求PLMN网络对UE的PDU会话配置资源等等。在这种情况下，使用漫游架构支持SNPN与PLMN互通，UE只在PLMN签约，签约数据可存储在PLMN的UDM，如图2所示：UE使用PLMN的公网签约选择SNPN ID，选择SNPN基站，在SNPN网络注册，并在SNPN建立PDU会话，SNPN网络根据UE公网签约确定本地分流(local break out，LBO)/归属路由(home routed，HR)模式。
除了终端的用户签约被PLMN提供外，还可以被第三方的SNPN网络提供，这种情况两个SNPN的互通与上面描述类似。
此外，用户签约还可以被第三方的AAA(authentication,authorization,accounting)服务器(AAA-server，AAA-S)提供。如图5所示，SNPN的网元，如AMF、SMF需要认证UE或者从AAA服务器中获取保存的签约数据，通过AAA代理(AAA-proxy，AAA-P)(例如NSSAAF或AUSF)与AAA服务器交互。
在UE的外部签约被其他PLMN、SNPN或AAA服务器提供时，UE在两个SNPN之间移动，这两个SNPN都可以如上面所示连接到保存UE签约的PLMN、SNPN或AAA服务器。在另一种场景中，UE从SNPN#1移动到SNPN#2时，SNPN#2也可以是保存UE签约的SNPN。另外UE也可以在SNPN与PLMN之间移动，在一种场景中，UE从SNPN#1移动到PLMN时，PLMN可以是VPLMN，也可以是保存UE签约的归属地PLMN(home PLMN，HPLMN)。
如图6至图9为几种典型的UE跨私网的移动场景。
图6场景下，UE可从SNPN#1移动到SNPN#2。其中，由第三方的AAA服务器保存UE签约，SNPN#1和SNPN#2可以连接到此AAA服务器。SNPN#1和SNPN#2之间支持图2所示的漫游互通方式。
图7a场景下，UE可从SNPN#1移动到SNPN#2或拜访地PLMN(visited PLMN，VPLMN)。其中，由HPLMN的UDM保存UE签约，SNPN#1和SNPN#2或VPLMN可以连接到此HPLMN。SNPN#1和SNPN#2或VPLMN之间支持图1所示的N3IWF互通方式。
图7b场景下，UE可从SNPN#1移动到SNPN#2或拜访地PLMN。其中，由HPLMN的UDM保存UE签约，SNPN#1和SNPN#2或VPLMN可以连接到此HPLMN。SNPN#1和HPLMN之间漫游互通，SNPN#2或VPLMN与HPLMN漫游互通。UE可以通过SNPN#1，SNPN#2/VPLMN建立HR PDU会话，即锚点UPF在HPLMN的PDU会话。
图7c场景下，UE可以在SNPN#1和SNPN#2之间移动。其中，由HPLMN的UDM保存UE签约，SNPN#1和SNPN#2可以连接到此HPLMN。SNPN#1和HPLMN之间漫游互通，SNPN#2与HPLMN之间通过N3IWF互通。UE可以通过SNPN#1建立HR PDU会话，即锚点UPF在HPLMN的PDU会话。UE可以按照图1所示的方式建立到HPLMN的PDU会话。
图8场景下，UE可从SNPN#1移动到HPLMN。其中，由HPLMN的UDM保存UE签约。SNPN#1和HPLMN之间支持图2所示的漫游互通方式。
图9场景下，UE可从SNPN#1移动到HPLMN。其中，由HPLMN的UDM保存UE签约。SNPN#1和HPLMN之间共享核心网网元，如AMF、SMF。之后，UE还可以继续从HPLMN移动到VPLMN，HPLMN和VPLMN之间采用图2所示的漫游互通方式。
本申请提供一种通信方法，用于解决UE在跨NPN网络之间的切换效率不高或无法正确切换的问题。
该通信方法可由终端设备和第一网络设备等执行。其中，该终端设备注册于第一网络(或称源网络或归属网络)，第一网络设备属于第二网络(或称目的网络)。这里的第一网络和/或第二网络是NPN网络，因此，当终端设备在第一网络和第二网络之间进行跨非公网切换时，可根据本申请实施例提供的通信方法提高切换效率和成功率。应理解，终端设备在第一网络和第二网络之间切换的场景，可参照图6-图9所示的场景。
示例性的，以终端设备为UE为例进行说明，本申请实施例提供的一种通信方法可包括图10所示的以下步骤：
S101：UE在第一网络建立第一PDU会话。
该第一PDU会话关联到数据网络名称(data network name，DNN)和单个网络切片选择辅助信息(single network slice selection assistance information，S-NSSAI)。
其中，本申请对于建立第一PDU会话的过程不予具体限定。
S102：UE向第二网络中的第一网络设备发送第一注册请求消息。
相应地，第一网络设备接收该第一注册请求消息。该第一注册请求消息可用于请求注册至第二网络。
示例性的，第一网络设备为部署在第二网络中的AMF。
可选的，第一注册请求消息可携带跨非公网切换指示(或称跨私网切换指示)，所述跨非公网切换指示用于指示所述终端设备进行跨非公网切换。
S103：第一网络设备获取UE的上下文。
其中，UE的上下文可存储于第一网络的第二网络设备中，或存储于数据存储节点。
该第二网络设备例如部署于第一网络的AMF，该AMF可管理UE在第一网络的注册请求。第一网络设备可从UDM获取UE在第一网络注册的信息，比如临时标识，进而获取第二网络设备的信息，从而通过第二网络设备获取UE的上下文。
该数据存储节点可由第一网络和第二网络共享，因此可由第一网络设备获取此前注册在第一网络的UE的上下文，例如，数据存储节点部署在第二网络并由第一网络和第二网络共用(即存储注册在第一网络和第二网络的UE的上下文)，或者，数据存储节点可部署于第一网络和第二网络以外的一个第三网络，并由第一网络和第二网络共用。该数据存储节点例如UDM或AAA。
S104：第一网络设备根据UE的上下文确定UE已在第一网络注册。
比如，UE上下文可包括第一网络的标识或第二网络设备的标识，第一网络设备可根据第一网络的标识或第二网络设备的标识获知UE已在第一网络注册。
S105：第一网络设备根据第一网络和第二网络之间的互通方式，确定第一信息。
该第一信息可指示在UE注册过程中如何切换PDU会话。
具体的，第一网络和第二网络之间的互通方式包括：第一网络与第二网络之间不互通、第一网络与第二网络之间基于如图1所示的N3IWF互通，以及，第一网络与第二网络之间基于漫游互通。
应理解，S105中，第一网络和第二网络之间的互通方式不同，则第一信息不同。
示例性的，在第一网络与第二网络之间不互通的情况下，第一信息可指示第一网络与第二网络之间不互通，比如，第一信息为不互通的指示信息。或者，第一信息可指示UE向第一网络设备发送第一PDU会话请求。该第一PDU会话请求包括值为初始请求(initial request)的请求类型(request type信元)，或者说，第一PDU会话请求用于请求建立初始PDU会话。其中，该第一PDU会话请求消息包括该DNN的信息以及该S-NSSAI的信息，或者说，第一PDU会话请求消息包括UE在第一网络建立的PDU会话所关联的DNN的信息以及该PDU会话所关联的S-NSSAI的信息。
在第一网络与第二网络之间基于N3IWF互通的情况下，第一信息可指示第一网络与第二网络之间基于N3IWF互通，比如，第一信息为基于N3IWF互通的指示信息。或者，第一信息可指示UE向第一网络设备发送第二PDU会话请求、并通过N3IWF向第二网络设备发送第二注册请求，以及向第二网络设备发送第三PDU会话请求消息。其中，第二PDU会话请求用于请求建立第二PDU会话，可由UE通过第二PDU会话建立UE与N3IWF之间的连接。该第二注册请求可用于请求通过N3GPP方式在第一网络注册。该第三PDU会话请求消息包括值为已有PDU会话(existing PDU session)的request type类型，或者说，该第三PDU会话请求消息用于建立已有PDU会话。其中，该第三PDU会话请求消息包括该DNN的信息以及该S-NSSAI的信息，或者说，第三PDU会话请求消息包括UE在第一网络建立的PDU会话所关联的DNN的信息以及该PDU会话所关联的S-NSSAI的信息。
在第一网络与第二网络之间基于漫游互通的情况下，第一信息可指示第一网络与第二网络之间基于漫游互通，比如，第一信息为基于漫游互通的指示信息。或者，第一信息可用于指示UE向第一网络设备发送第四PDU会话请求消息。该第四PDU会话请求消息包括值为existing PDU session的request type信元，或者说，第四PDU会话请求消息用于请求建立已有PDU会话。其中，该第四PDU会话请求消息包括该DNN的信息以及该S-NSSAI的信息，或者说，第四PDU会话请求消息包括UE在第一网络建立的PDU会话所关联的DNN的信息以及该PDU会话所关联的S-NSSAI的信息。
S106：第一网络设备向UE发送第一信息。
相应地，UE接收来自于AMF#2的第一信息，该第一信息根据SNPN#1与SNPN#2之间的互通方式确定。
S107：UE根据第一信息建立UE的PDU会话，该PDU会话与该DNN和该S-NSSAI关联。
具体的，在第一网络与第二网络之间不互通的情况下，或者说，在第一信息指示第一网络与第二网络之间不互通，或者指示UE向第一网络设备发送第一PDU会话请求的情况下，UE可向第一网络设备发送第一PDU会话请求消息，该第一PDU会话包括值为initial request的request type信元和该DNN的信息以及该S-NSSAI的信息。据此，在第一网络和第二网络不互通的方式下，UE可在第二网络新建关联至DNN和S-NSSAI的PDU会话，实现关联至该DNN和S-NSSAI的PDU会话的恢复。由于不互通方式下，基于N3IWF互通和基于漫游互通的PDU会话恢复方式均不可行，因此UE根据第一信息执行相应切换过程可提高切换效率，避免试错。
在第一网络与第二网络之间基于N3IWF互通的情况下，或者说，在第一信息用于指示第一网络与所述第二网络之间基于N3IWF互通，或指示UE向第一网络设备发送第二 PDU会话请求、通过N3IWF向第二网络设备发送第二注册请求，以及向第二网络设备发送第三PDU会话请求消息的情况下，UE可向第一网络设备发送第二PDU会话请求消息，该第二PDU会话请求用于请求建立第二PDU会话。UE还可通过第二PDU会话建立与N3IWF的连接，该N3IWF属于第一网络。此后，UE可通过该连接向第二网络设备发送第二注册请求，该第二注册请求用于请求通过N3GPP方式注册至第一网络。UE还可向第二网络设备发送第三PDU会话请求消息，已建立已有PDU会话(该PDU会话可称为第三PDU会话)，该第三PDU绘画请求消息可包括该DNN的信息以及该S-NSSAI的信息。据此，在第一网络和第二网络基于N3IWF互通的方式下，UE可通过N3IWF和第二网络设备建立关联至该DNN的信息以及该S-NSSAI的第三PDU会话，实现UE的关联至该DNN和S-NSSAI的PDU会话的恢复。由于基于N3IWF互通方式下，不互通和基于漫游互通的PDU会话恢复方式均不可行，因此UE根据第一信息执行相应切换过程可提高切换效率，避免试错。
在第一网络与第二网络之间基于漫游互通的情况下，或者说，在第一信息用于指示第一网络与所述第二网络之间基于漫游互通，或指示UE向第一网络设备发送第四PDU会话请求消息的情况下，UE可向第一网络设备发送第四PDU会话请求消息。其中，该第四PDU会话请求消息包括值为existing PDU session的request type信元，或者说，第四PDU会话请求消息用于请求建立已有PDU会话(该PDU会话可称为第四PDU会话)。并且，该第四PDU会话请求消息包括该DNN的信息以及该S-NSSAI的信息。因此，在第一网络和第二网络基于漫游互通的方式下，UE可通过第一网络设备建立关联至该DNN的信息以及该S-NSSAI的第四PDU会话，实现UE的关联至该DNN和S-NSSAI的PDU会话的恢复。由于基于漫游互通方式下，不互通和基于N3IWF互通的PDU会话恢复方式均不可行，因此UE根据第一信息执行相应切换过程可提高切换效率，避免试错。
基于以上流程，在从第一网络注册至第二网络后，UE可接收来自于第二网络中的第一网络设备的第一信息，由于第一信息与第一网络和第二网络之间的互通方式相关，根据第一信息能够更为高效地恢复UE的关联至DNN和S-NSSAI的PDU会话，以提高切换效率和确保业务连续性。
应理解，以上第一网络和第二网络中的一个为NPN网络。比如，第一网络和第二网络中的至少一个为SNPN。
在第一网络与第二网络之间基于漫游互通的情况下，还可支持UE路径的数据无损切换。示例性的，UE可在第四PDU会话请求消息中携带无损切换指示。或者，无损切换指示也可独立于第四PDU会话请求消息独立发送。第一网络设备可将无损切换指示发送至SMF，其中，该SMF为管理第一PDU会话的SMF；或者，该SMF为中间SMF，用于连接至管理第一PDU会话的SMF，此后可由该中间SMF将无损切换指示转发至管理第一PDU会话的SMF。
管理第一PDU会话的SMF在接收到无损切换指示后，可向第一UPF发送第二信息，以指示第一UPF在第一PDU会话的路径切换后向第一接入网网元发送结束标记，以及，用于指示第一UPF将来自于第一接入网网元的UE的下行数据通过切换后的路径向UE转发，该下行数据包括该结束标记。以及，管理第一PDU会话的SMF可向第一接入网网元发送第三信息，以指示第一接入网网元将其缓存的UE的下行数据转发至第一UPF，直到接收并转发该结束标记。以上第一PDU会话为第一接入网网元与第一UPF之间的PDU会 话。据此，可由第一UPF和第一接入网网元将路径切换前UE的下行数据通过切换后的路径转发至UE，实现无损路径切换。
下面以第一网络为SNPN#1，且第二网络为SNPN#2为例进行说明，其中，这里的SNPN#2也可替换为VPLMN#2(即一个VPLMN)。
如图11所示，本申请实施例提供的一种通信方法可包括以下流程：
S201：UE在SNPN#1注册，并建立第一PDU会话。其中，第一PDU会话的SMF和UPF分别为SMF#1和UPF#1。该第一PDU会话可关联至第一DNN和第一S-NSSAI。
S202：SMF#1向UDM或者AAA服务器发送SMF注册消息。该注册消息可包括UE ID、SNPN#1 ID、SMF#1 ID和第一PDU会话的ID。该UDM或AAA服务器可部署于PLMN或第三网络。
S203：UE移动到目标网络SNPN#2，UE发送第一注册请求消息给SNPN#2中的AMF#2(图11中AMF#2作为第一网络设备)，携带UE ID。
可选的，该第一注册请求消息中可携带跨私网HO指示。其中，该跨私网HO指示用于指示AMF#2注册的目的是进行跨私网切换，而非初始注册。HO指示可以为位置更新注册或一个新的信元。
S204：如果AMF#2与AMF#1之间有接口，AMF#2可以从AMF#1获取UE的上下文，包括UE ID、SNPN#1 ID、SMF#1 ID或第一PDU会话的ID中的至少一个信息。其中，AMF#1的信息可由AMF#2从UDM或AAA服务器获取。否则，如果AMF#2与AMF#1之间没有接口，则AMF#2可从UDM或者AAA获取UE的上下文。
S205：AMF#2根据UE的跨私网HO指示或UE上下文，如SNPN#1 ID或SMF#1 ID，确定UE在进行跨私网切换，并根据SNPN#2与SNPN#1的互通方式(不互通、基于N3IWF方式互通或基于漫游互通)确定切换方式，如确定UE按照漫游互通或不按照漫游互通等进行切换。
S206：AMF#2向UE发送注册响应消息，携带切换方式指示(即第一信息)。如果SNPN#1与SNPN#2之间不互通，该切换方式信息可指示UE按照不互通的方式进行切换，或者，指示SNPN#1与SNPN#2之间不互通；如果SNPN#1与SNPN#2之间基于N3IWF方式互通，该切换方式信息可指示UE按照基于N3IWF方式互通的方式进行切换，或者，指示SNPN#1与SNPN#2之间基于N3IWF方式互通；如果SNPN#1与SNPN#2之间按照漫游互通，该切换方式信息可指示UE按照漫游互通的方式进行切换，或者，指示SNPN#1与SNPN#2之间按照漫游互通。
之后执行S207-S209中的一项。
S207：如果SNPN#1与SNPN#2之间不互通，则UE重新建立PDU会话，即向AMF#2发送request type为initial request的第一PDU会话请求消息。该第一PDU会话请求消息中携带第一DNN和第一S-NSSAI，因此新建立的PDU会话可关联至第一DNN和第一S-NSSAI。
此种情况下，切换方式指示可用于指示SNPN#1与SNPN#2之间不互通，或用于指示UE向AMF#2发送该第一PDU会话请求。
S208：如果SNPN#1与SNPN#2之间基于N3IWF方式互通，则UE在SNPN#2首先建立连接到SNPN#1的基于N3IWF的PDU会话(即第二PDU会话)，建立用户面连接；然后UE通过N3IWF在SNPN#1发起N3GPP注册，或者说，通过N3IWF向AMF#1发送 第二注册请求，以请求通过N3GPP方式注册至第一网络，之后UE可发起PDU会话从3GPP切换到N3GPP的流程，即发起request type为existing PDU session的第三PDU会话请求消息，在第三PDU会话请求消息中携带第一DNN和第一S-NSSAI，因此新建立的N3GPP的PDU会话可关联至第一DNN和第一S-NSSAI。
此种情况下，切换方式指示可用于指示SNPN#1与SNPN#2之间基于N3IWF方式互通，或用于指示UE在SNPN#2首先建立连接到SNPN#1的基于N3IWF的PDU会话，并发起PDU会话从3GPP切换到N3GPP的流程。
S209：如果SNPN#1与SNPN#2之间基于漫游互通，则UE在SNPN#2发起PDU会话从SNPN#1到SNPN#2的切换流程，即向AMF#2发送request type为existing PDU session的第四PDU会话请求消息，此后执行S210-S220。其中，第四PDU会话请求消息中携带该DNN的信息和该S-NSSAI的信息，以请求恢复关联至该DNN和S-NSSAI的PDU会话。
可选的，如果UE需要无损切换，则可以在第四PDU会话请求中额外携带无损切换指示。
此种情况下，切换方式指示可用于指示SNPN#1与SNPN#2之间基于漫游互通，或用于指示UE在SNPN#2发起PDU会话从SNPN#1到SNPN#2的切换流程。
S210：AMF#2根据跨私网HO指示、existing PDU session的request type或SMF#1 ID，确定UE在进行跨私网切换，并确定插入I-SMF。
S211：AMF#2向NRF发送SMF发现请求消息。
S212：NRF根据SMF发现请求消息，向AMF#2发送候选SMF。
S213：AMF#2根据候选SMF选择SMF#2作为I-SMF。
S214：AMF#2向SMF#2发送第四PDU会话请求消息和跨私网HO指示。
S215：SMF#2向SMF#1发送第四PDU会话请求消息和跨私网HO指示。
可选地，如果SMF#2收到UE发送的无损切换指示，SMF#2可以将无损切换指示转发给SMF#1。
可选的，SMF#2在按照现有机制插入UPF#2作为I-UPF(如UPF#2)时，额外地，SMF#2可根据HO指示，配置I-UPF上的计费规则。
S216：SMF#1向UPF#1发送路径切换指示，以指示UPF#1切换到达UE的路径。
例如，UPF#1将从UPF#1达到UE的路径从UPF#1→RAN#1→UE，切换为UPF#1→UPF#2→RAN#2→UE。
此外，SMF根据跨私网HO指示和本地配置或无损切换指示，通过第二信息指示UPF#1保持业务连续性。
S217：UPF#1在切换到新路径后，根据SMF的第二信息在旧路径上向RAN#1发送结束标记。
这里的旧路径，是指UPF#1与RAN#1之间路径。
S218：SMF#1(或AMF#1)向RAN#1发送释放请求，以请求RAN#1释放第一PDU会话。
此外，SMF#1(或AMF#1)在接收到跨私网HO指示后，可根据本地配置确定需要进行无损切换，从而向RAN#1发送第三指示，以指示RAN#1在释放上下文之前，把缓存的下行数据(包括UPF#1发送的结束标记)转发到UPF#1。后续可由UPF#1通过新路径将来自于RAN#1的数据转发至UE。
或者，SMF#1/AMF#1可在接收到来自于SMF#2的无损切换指示后，通过第三信息指示RAN#1在释放上下文之前，把缓存的下行数据(包括UPF#1发送的结束标记)转发到UPF#1。后续可由UPF#1通过新路径将来自于RAN#1的数据转发至UE。
S219：RAN#1将缓存的UE数据转发至UPF#1，并释放第一PDU会话的资源，该数据包括结束标记。
S220：UPF#1把来自于RAN#1的数据在新路径转发至UE，即：数据在UPF#1→UPF#2→RAN#2→UE的路径上转发。后续UE的数据通过
Figure PCTCN2021112097-appb-000001
的路径转发。
如果UPF#1收到SMF的切换路径的指示，则在下行方向上转发新的数据之前，需要首先转发来自于RAN#1的数据，即UPF#1先转发从原路径上接收到的报文，直到收到结束标记，再转发新的下行数据包文。
S221：在SNPN#2恢复PDU会话。
采用以上方法，可由AMF#2指示UE采取的跨私网切换的方式，由UE通过指示的切换方式指示执行跨私网切换，使UE正确切换到目标网络，以提高跨私网切换的效率。此外，在基于漫游方式进行跨私网切换时，可以为UE提供数据无损切换。
如图12所示，以第一网络为SNPN#1，且第二网络为HPLMN#2为例对本申请实施例提供的另一种通信方法进行说明。其中，这里的HPLMN#2也可替换为归属地SNPN(home SNPN，H-SNPN)H-SNPN#2，该场景如图8所示。
如图12所示，本申请实施例提供的另一种通信方法可包括以下流程：
S301：UE通过RAN#1在SNPN#1注册，并建立第一PDU会话。其中，第一PDU会话的SMF和UPF分别为SMF#1和UPF#1。该第一PDU会话可关联至第一DNN和第一S-NSSAI。
S302：SMF#2向UDM发送SMF注册消息。该注册消息可包括UE ID、SNPN#1 ID、SMF#1 ID和第一PDU会话的ID。其中，UDM部署于HPLMN#2。
S303：UE移动到目标网络HPLMN#2，UE发送第一注册请求消息给HPLMN#2中的AMF#2(图12中AMF#2作为第一网络设备)，携带UE ID。该第一注册请求消息中还可携带跨私网HO指示。其中，该跨私网HO指示用于指示AMF#2注册的目的是进行跨私网切换，而非初始注册，HO指示可以为位置更新注册或一个新的信元。
S304：如果AMF#2与AMF#1之间有接口，AMF#2可以从AMF#1获取UE的上下文，包括UE ID、SNPN#1 ID、SMF#1 ID或第一PDU会话的ID中的至少一个信息；否则，如果AMF#2与AMF#1之间没有接口，则AMF#2从UDM获取UE的上下文。
S305：AMF#2根据UE的跨私网HO指示或UE上下文，如SNPN#1 ID或SMF#2 ID，确定UE在进行跨私网切换，并根据HPLMN#2与SNPN#1的互通方式确定切换方式，其中，HPLMN#2与SNPN#1的互通方式为漫游互通。
S306：AMF#2向UE发送注册响应消息，携带切换方式指示(即第一信息)。该切换方式信息可指示UE按照漫游互通的方式进行切换，或者，指示SNPN#1与HPLMN#2之间按照漫游互通。
S307：UE在HPLMN#2发起PDU会话从SNPN#1到HPLMN#2的切换流程，即向AMF#2发送request type为existing PDU session的第四PDU会话请求消息。其中，第四 PDU会话请求消息中携带该DNN的信息和该S-NSSAI的信息，以请求恢复关联至该DNN和S-NSSAI的PDU会话。
可选的，如果UE需要无损切换，则可以在会话请求中额外携带无损切换指示。
S308：AMF#2根据跨私网HO指示、existing PDU session的request type或SMF#1 ID，确定UE在进行跨私网切换，并确定插入I-SMF。
S309：AMF#2向NRF发送SMF发现请求。
S310：NRF根据SMF发现请求，向AMF#2发送候选SMF。
S311：AMF#2根据候选SMF选择SMF#2作为I-SMF。
S312：AMF#2向SMF#2发送第四PDU会话请求消息和跨私网HO指示。
S313：SMF#2向SMF#2发送第四PDU会话请求消息和跨私网HO指示，同时向SMF#1发送跨私网HO指示。
可选地，如果SMF#2收到UE发送的无损切换指示，SMF#2可以将无损切换指示转发给SMF#1。
可选的，SMF#2在按照现有机制插入UPF#2作为I-UPF(如UPF#2)时，额外地，SMF#2可根据HO指示，配置I-UPF上的计费规则。
S314：SMF#1向UPF#1发送路径切换指示，以指示UPF#1切换到达UE的路径。
例如，UPF#1将从UPF#1达到UE的路径从UPF#1→RAN#1→UE，切换为UPF#1→UPF#2→RAN#2→UE。
此外，SMF根据跨私网HO指示和本地配置或无损切换指示，通过第二信息指示UPF#1保持业务连续性。
S315：UPF#1在切换到新路径后，可以根据第二信息在旧路径上向RAN#1发送结束标记。
这里的旧路径，是指UPF#1与RAN#1之间路径。
S316：SMF#1(或AMF#1)向RAN#1发送释放请求，以请求RAN#1释放第一PDU会话。
此外，SMF#1(或AMF#1)在接收到跨私网HO指示后，可根据本地配置确定需要进行无损切换，从而通过第三信息指示RAN#1在释放上下文之前，把缓存的下行数据(包括UPF#1发送的结束标记)转发到UPF#1。或者，SMF#1/AMF#1可在接收到来自于SMF#2的无损切换指示后，通过第三信息指示RAN#1在释放上下文之前，把缓存的下行数据(包括UPF#1发送的结束标记)转发到UPF#1。后续可由UPF#1通过新路径将来自于RAN#1的数据转发至UE。
S317：RAN#1将缓存的UE数据转发至UPF#1，该数据包括结束标记，并释放第一PDU会话的资源。
S318：UPF#1把来自于RAN#1的数据通过新路径转发至UE，即：数据在UPF#1→UPF#2→RAN#2→UE的路径上转发。后续UE的数据通过
Figure PCTCN2021112097-appb-000002
Figure PCTCN2021112097-appb-000003
的路径转发。
如果UPF#1收到SMF的切换路径的指示，则在下行方向上转发新的数据之前，需要首先转发来自于RAN#1的数据，即UPF#1先转发从原路径上接收到的报文，直到收到结束标记，再转发新的下行数据包文。
S319：在HPLMN#2恢复PDU会话。
采用以上方法，在第一网络与第二网络共用UDM的情况下，可由核心网指示UE采取基于漫游的跨私网切换的方式，以提高跨私网切换的效率。此外，可以为UE提供数据无损切换。
再比如图9所示的场景，UE从SNPN#1切换至HPLMN#2(或H-SNPN#2)，此时SNPN#1与HPLMN#2(或H-SNPN#2)共用核心网，则本申请实施例提供的通信方法可包括如图13所示的以下步骤：
S401：UE通过RAN#1在SNPN#1注册，并建立第一PDU会话。其中，第一PDU会话的SMF和UPF分别为SMF#2和UPF#2。该第一PDU会话可关联至第一DNN和第一S-NSSAI。
S402：SMF#2向UDM发送SMF注册消息。该注册消息可包括UE ID、SNPN#1 ID、SMF#2 ID和第一PDU会话的ID。
S403：UE移动到目标网络HPLMN#2，UE发送第一注册请求消息给HPLMN#2中的AMF#2(图13中AMF#2作为第一网络设备)，携带UE ID。该第一注册请求消息中还可携带跨私网HO指示。其中，该跨私网HO指示用于指示AMF#2注册的目的是进行跨私网切换，而非初始注册，HO指示可以是位置更新注册或新的信元。
S404：AMF#2从UDM获取UE的上下文。
S405：AMF#2根据UE的跨私网HO指示或UE上下文，如SNPN#1 ID，确定UE在进行跨私网切换，并根据HPLMN#2与SNPN#1的互通方式确定切换方式，其中，HPLMN#2与SNPN#1的互通方式为漫游互通。
S406：AMF#2向UE发送注册响应消息，携带切换方式指示(即第一信息)。该切换方式信息可指示UE按照漫游互通的方式进行切换，或者，指示SNPN#1与HPLMN#2之间按照漫游互通。
S407：UE在HPLMN#2发起PDU会话从SNPN#1到HPLMN#2的切换流程，即向AMF#2发送request type为existing PDU session的第四PDU会话请求消息。其中，第四PDU会话请求消息中携带该DNN的信息和该S-NSSAI的信息，以请求恢复关联至该DNN和S-NSSAI的PDU会话。
可选的，如果UE需要无损切换，则可以在会话请求中额外携带无损切换指示。
S408：AMF#2根据跨私网HO指示、existing PDU session的request type或SNPN#1 ID，确定UE在进行跨私网切换。
S409：AMF#2向SMF#2转发第四PDU会话请求消息和跨私网HO指示。
S410：在HPLMN#2恢复第一PDU会话。
S411：SMF#2(或AMF#2)向RAN#1发送释放请求，以请求RAN#1释放第一PDU会话。
此外，SMF#2/AMF#2在接收到跨私网HO指示后，可根据本地配置确定需要进行无损切换，从而通过第三信息指示RAN#1在释放上下文之前，把缓存的下行数据转发到UPF#2。或者，SMF#2/AMF#2可在接收到来自于UE的无损切换指示后，通过第三信息指示RAN#1在释放PDU会话之前，把缓存的下行数据转发到UPF#2。后续可由UPF#2通过新路径将来自于RAN#1的数据转发至UE。
S412：RAN#1将缓存的UE数据转发至UPF#2，并释放第一PDU会话的资源，该数据包括结束标记。
S413：UPF#2把来自于RAN#1的数据报文在新路径上转发，即：数据报文在UPF#2<->RAN#2<->UE转发；如果UPF#2收到SMF的切换路径的指示，则在转发新的下行数据报文之前，需要首先转发从RAN#1即原路径上接收到的报文，直到收到结束标记。
采用以上方法，在第一网络与第二网络共用核心网的情况下，可由核心网指示UE采取基于漫游的跨私网切换的方式，以提高跨私网切换的效率。此外，可以为UE提供数据无损切换。
当UE注册在归属网络，即第一网络为归属网络，UE通过源网络接入归属网络，并建立在归属网络中的PDU会话，此时本申请实施例提供的通信方法可包括图14a和/或图14b所示步骤。其中，这里的归属网络可以是HPLMN或者归属地SNPN(home SNPN，HSNPN)。
图14a所示，为第一网络为HPLMN且第二网络为SNPN#2时，本申请实施例提供的另一种通信方法。该方法可应用于图7b/7c所示场景。这里的SNPN#2也可替换为VPLMN#2(即一个VPLMN)。
该方法可包括以下步骤：
S601：UE在SNPN#1注册并建立第一PDU会话，该第一PDU会话的锚点UPF为HPLMN中的UPF#3，该PDU会话的锚点SMF为HPLMN中的SMF#3。该第一PDU会话可关联至第一DNN和第一S-NSSAI。
其中，SNPN#1与HPLMN基于漫游方式互通。
S602：SMF#1和SMF#3分别向UDM发送SMF注册消息。该注册消息可包括UE ID、SNPN#1 ID、SMF#1 ID(或SMF#3 ID)和第一PDU会话的ID。该UDM可部署于HPLMN。
S603：UE移动到目标网络SNPN#2，UE发送第一注册请求消息给SNPN#2中的AMF#2，其中携带UE ID。
可选的，该第一注册请求消息中可携带跨私网HO指示。其中，该跨私网HO指示用于指示AMF#2注册的目的是进行跨私网切换，而非初始注册。HO指示可以为位置更新注册或一个新的信元。
S604：AMF#2根据UE的跨私网HO指示，确定UE在进行跨私网切换，并根据SNPN#2与HPLMN的互通方式(基于非漫游互通或基于漫游互通)确定切换方式，如确定UE按照漫游互通或不按照漫游互通等进行切换。
其中，AMF#2可根据UE的第一注册请求消息中的UE ID(例如用户永久标识(subscription permanent identifier，SUPI)或用户隐藏标识(subscription concealed identifier，SUCI))确定UE的归属网络的ID，可能是HPLMN的网络ID，也可能是SNPN#2的网络ID。同时AMF#2能够从RAN获取SNPN#2的网络ID，之后根据归属网络的ID确定SNPN#2与HPLMN的互通方式。
S605：AMF#2向UE发送注册响应消息，携带切换方式指示(即第一信息)。
如果SNPN#2与HPLMN基于非漫游方式互通，切换方式指示可指示SNPN#2与HPLMN基于非漫游方式互通。或者，切换方式指示可指示UE：如果UE不支持到HPLMN的N3IWF，例如没有HPLMN的N3IWF配置或不支持连接到N3IWF，则在注册到SNPN#2后不用建立到HPLMN的第一PDU会话。
另外，如果SNPN#2与HPLMN基于非漫游方式互通，切换方式指示还可指示UE：如果UE支持到HPLMN的N3IWF，例如UE有HPLMN的N3IWF配置或支持连接到N3IWF，则UE建立连接到HPLMN的N3IWF的PDU会话，通过该PDU会话触发第一PDU会话从3GPP切换到N3GPP的流程，并删除第一PDU会话的SMF#1/UPF#1。
如果SNPN#2与HPLMN支持基于漫游方式互通时，切换方式指示可指示SNPN#2与HPLMN支持基于漫游方式互通，或者，切换方式指示可指示UE按照以下方式恢复第一PDU会话：AMF#2触发现有机制中的PDU会话的I-SMF/I-UPF切换流程，选择SMF#2/UPF#2替代原来的SMF#1/UPF#1，恢复PDU会话。
UE之后根据切换方式指示执行S606-S608中的一项。
S606：如果SNPN#2与HPLMN基于非漫游方式互通，但UE不支持到HPLMN的N3IWF，则UE不再尝试向SNPN#2建立该第一PDU会话。
S607：如果SNPN#2与HPLMN基于非漫游方式互通，且UE支持到HPLMN的N3IWF，则在SNPN#2首先建立连接到HPLMN的N3IWF的PDU会话(即第二PDU会话)，建立用户面连接；然后UE通过N3IWF在SNPN#1发起第一PDU会话从3GPP到N3GPP的切换，即向SNPN#1发送request type为existing PDU session的第三PDU会话请求消息，在第三PDU会话请求消息中携带第一DNN和第一S-NSSAI，因此切换后的N3GPP的PDU会话可关联至第一DNN和第一S-NSSAI，并删除第一PDU会话的SMF#1和UPF#1。
S608：如果SNPN#2与HPLMN基于漫游方式互通，UE可向AMF#2发送request type为existing PDU session的第四PDU会话请求消息，其中携带第一DNN和第一S-NSSAI，以请求恢复关联至该DNN和S-NSSAI的PDU会话。当AMF#2接收到第四会话请求后，触发现有机制中的PDU会话的I-SMF/I-UPF切换流程，选择SMF#2/UPF#2替代原来的SMF#1/UPF#1，恢复第一PDU会话。
此种情况下，切换方式指示可用于指示SNPN#1与SNPN#2之间基于漫游互通，或用于指示UE在SNPN#2发起PDU会话从SNPN#1到SNPN#2的切换流程。具体切换方式可参照S210-S221所示步骤。
基于以上流程，当源SNPN#1与HPLMN基于漫游方式互通，且注册在SNPN#1的UE建立HPLMN的HR PDU会话时，可由SNPN#2中的AMF指示UE进行PDU会话切换，提高PDU会话切换效率。
应理解，以上流程中HPLMN可替换为归属地SNPN(home SNPN，HSNPN)。
图14b所示，为第一网络为HPLMN且第二网络为SNPN#2时，本申请实施例提供的另一种通信方法。该方法可应用于图7b/7c所示场景。这里的SNPN#2也可替换为VPLMN#2(即一个VPLMN)。
该方法可包括以下步骤：
S701：UE通过SNPN#1连接到HPLMN的N3IWF，通过N3WIF在HPLMN注册并建立第一PDU会话，该第一PDU会话的锚点UPF为HPLMN中的UPF#3，该PDU会话的锚点SMF为HPLMN中的SMF#3。该第一PDU会话可关联至第一DNN和第一S-NSSAI。
其中，SNPN#1与HPLMN基于N3IWF互通。
S702：SMF#3向UDM发送SMF注册消息。该注册消息可包括UE ID、HPLMN的网络ID、SMF#3 ID和第一PDU会话的ID。该UDM可部署于HPLMN。
S703：UE移动到目标网络SNPN#2，UE发送第一注册请求消息给SNPN#2中的AMF#2，其中携带UE ID。
可选的，该第一注册请求消息中可携带跨私网HO指示。其中，该跨私网HO指示用于指示AMF#2注册的目的是进行跨私网切换，而非初始注册。HO指示可以为位置更新注册或一个新的信元。
S704：AMF#2根据UE的跨私网HO指示，确定UE在进行跨私网切换，并根据SNPN#2与HPLMN的互通方式(基于非漫游发送互通或基于漫游互通)确定切换方式，如确定UE按照漫游互通或不按照漫游互通等进行切换。
其中，AMF#2可根据UE的第一注册请求消息中的UE ID(例如SUPI或SUCI)确定UE的归属网络的ID，归属网络的ID可能是HPLMN的网络ID，也可能是SNPN#2的网络ID。同时AMF#2能够从RAN获取SNPN#2的网络ID，之后根据归属网络的ID确定SNPN#2与HPLMN的互通方式。
S705：AMF#2向UE发送注册响应消息，携带切换方式指示(即第一信息)。
如果SNPN#2与HPLMN基于非漫游方式互通，切换方式指示可指示SNPN#2与HPLMN基于非漫游方式互通。或者，切换方式指示可指示UE：如果UE不支持到HPLMN的N3IWF，例如没有HPLMN的N3IWF配置或不支持连接到N3IWF，则在注册到SNPN#2后不用建立到HPLMN的第一PDU会话。
另外，如果SNPN#2与HPLMN基于非漫游方式互通，切换方式指示还可指示UE：如果UE支持到HPLMN的N3IWF，例如UE有HPLMN的N3IWF配置或支持连接到N3IWF，则UE建立连接到HPLMN的N3IWF的PDU会话，通过该PDU会话在HPLMN通过N3GPP建立PDU会话，该PDU会话关联到第一DNN和第一S-NSSAI。
如果SNPN#2与HPLMN支持基于漫游方式互通时，切换方式指示可指示SNPN#2与HPLMN支持基于漫游方式互通，或者，切换方式指示可指示UE按照以下方式恢复第一PDU会话：AMF#2触发现有机制中的PDU会话的I-SMF/I-UPF插入流程，新插入SNPN#2中的SMF#2和/或UPF#2。
UE之后根据切换方式指示执行S706-S708中的一项。
S706：如果SNPN#2与HPLMN基于非漫游方式互通，但UE不支持到HPLMN的N3IWF，则UE不再尝试建立SNPN#2的第一PDU会话。
S707：如果SNPN#2与HPLMN基于非漫游方式互通，且UE支持到HPLMN的N3IWF，则在SNPN#2首先建立连接到HPLMN的N3IWF的PDU会话(即第二PDU会话)，建立用户面连接；然后UE通过N3IWF建立到HPLMN的request type为existing PDU session的N3GPP PDU会话，该PDU会话关联到第一DNN和第一S-NSSAI。
S708：如果SNPN#2与HPLMN基于漫游方式互通，UE可向AMF#2发送request type为existing PDU session的第四PDU会话请求消息，其中携带该第一DNN和该第一S-NSSAI，以请求恢复关联至该DNN和S-NSSAI的PDU会话。当AMF#2接收到第四会话请求后，触发现有机制中的PDU会话的I-SMF/I-UPF插入流程，新插入SNPN#2中的SMF#2和/或UPF#2，用于将第一PDU会话从N3GPP切换到3GPP。
此种情况下，切换方式指示可用于指示SNPN#1与SNPN#2之间基于漫游互通，或用于指示UE在SNPN#2发起PDU会话从SNPN#1到SNPN#2的切换流程。具体切换方式可参照S210-S221所示步骤。
基于以上流程，当源SNPN#1与HPLMN基于N3IWF互通，且注册在SNPN#1的UE通过HPLMN的N3IWF建立HPLMN的PDU会话时，可由SNPN#2中的AMF指示UE进行PDU会话切换，提高PDU会话切换效率。
应理解，以上流程中HPLMN可替换为归属地SNPN。
如图14c所示，本申请实施例提供的另一种通信方法可包括以下步骤：
S501：UE在第一网络建立第一PDU会话。
该第一PDU会话关联到DNN和S-NSSAI。
S502：UE向第二网络中的第一网络设备发送第一注册请求消息。
相应地，第一网络设备接收该第一注册请求消息。该第一注册请求消息可用于请求注册至第二网络。
示例性的，第一网络设备为部署在第二网络中的AMF。
可选的，第一注册请求消息可携带跨非公网切换指示，所述跨非公网切换指示用于指示所述终端设备进行跨非公网切换。
S503：按照第一顺序建立UE的PDU会话，该PDU会话与该DNN和该S-NSSAI关联。该第一顺序可指示第三方式、第二方式和第一方式分别的执行顺序，其中，第三方式优先于第二方式和第一方式，第二方式优先于第一方式。
应理解，第一顺序可以仅包括第三方式、第二方式和第一方式中的两种方式的先后顺序，此时终端设备不再执行第一顺未包括的方式，以进一步提高切换效率。
上述第一顺序可指示上述第三方式优先于第二方式，且第二方式优先于第一方式，UE可优先按照第三方式建立PDU会话，如果成功建立关联到该DNN和该S-NSSAI的PDU会话，则不再尝试通过第二方式和第一方式建立PDU会话；否则，如果根据第三方式无法建立关联到该DNN和该S-NSSAI的PDU会话，则UE可尝试根据第二方式建立关联到该DNN和该S-NSSAI的PDU会话；如果根据第二方式无法建立关联到该DNN和该S-NSSAI的PDU会话，则UE可尝试根据第一方式建立关联到该DNN和该S-NSSAI的PDU会话。
采用以上流程，UE在从第一网络注册至第二网络后可按照第一顺序通过第三方式、第二方式和/或第一方式恢复PDU会话，以提高切换效率。
可选的，第一方式、第二方式和第三方式可分别对于第一网络与第二网络之间的一种互通方式。换句话说，第一方式、第二方式和第三方式分别为第一网络和第二网络之间的一种互通方式下UE建立关联到DNN和S-NSSAI的PDU会话的一种方式。
示例性的，第一方式可包括不互通切换方式。不互通切换方式可用于在第一网络和第二网络不互通的情况下实现UE的PDU会话的切换，该不互通切换方式具体包括，终端设备向第一网络设备发送第一PDU会话请求消息，该第一PDU会话请求消息包括值为initial request的request type信元、该DNN的信息以及该S-NSSAI的信息。或者说，第一方式可包括第一网络和第二网络不互通时，UE建立关联到该DNN和S-NSSAI的PDU会话时的方式，具体步骤可参见前述说明。
第二方式可包括N3IWF互通切换方式，该N3IWF互通切换方式可用于在第一网络与第二网络之间基于N3IWF互通时实现UE的PDU会话切换。N3IWF互通切换方式可包括以下步骤：UE向第一网络设备发送第二PDU会话请求消息，该第二PDU会话请求用于请求建立第二PDU会话，UE通过该第二PDU会话建立与N3IWF的连接，该N3IWF属于第一网络；UE通过该连接向第二网络设备发送第二注册请求消息，该第二注册请求消息用于请求通过N3GPP方式在该第一网络注册，该第二网络设备属于该第一网络；UE向第二网络设备发送第三PDU会话请求消息，该第三PDU会话请求消息包括值为existing PDU session的request type信元、该DNN的信息以及该S-NSSAI的信息。或者说，第二 方式可包括第一网络和第二网络基于N3IWF互通时，UE建立关联到该DNN和S-NSSAI的PDU会话时的方式，具体步骤可参见前述说明。
第三方式可包括漫游互通切换方式，该漫游互通切换方式可用于在第一网络与第二网络之间基于漫游互通时实现UE的PDU会话切换。漫游互通切换方式可包括以下步骤：终端设备向第一网络设备发送第四PDU会话请求消息，该第四PDU会话请求消息包括值为existing PDU session的request type信元、所述DNN的信息以及所述S-NSSAI的信息。可选的，该第四PDU会话请求消息可包括无损切换指示，以实现无损切换，具体步骤可参照图11至图13中基于SMF#1(或UPF#2)、UPF#1(或UPF#2)和RAN#1实现的无损切换步骤。或者说，第三方式可包括第一网络和第二网络基于漫游互通时，UE建立关联到该DNN和S-NSSAI的PDU会话时的方式，具体步骤可参见前述说明。以上第三方式可替换为漫游互通切换方式，或者说，可将第三方式称为漫游互通切换方式，用于在第一网络和第二网络之间通过漫游互通时实现UE的PDU会话切换。
因此，在终端设备从第一网络切换至第二网络时，可优先通过漫游互通切换方式恢复关联到该DNN和S-NSSAI的PDU会话，次优方案可通过N3IWF互通切换方式恢复关联到该DNN和S-NSSAI的PDU会话，再次可通过不互通切换方式恢复关联到该DNN和S-NSSAI的PDU会话，以提高切换效率。
示例性的，第一顺序可指示上述第三方式优先于第二方式，且第二方式优先于第一方式，则UE可优先按照第三方式建立PDU会话，如果成功建立关联到该DNN和该S-NSSAI的PDU会话，则不再尝试通过第二方式和第一方式建立PDU会话；否则，如果根据第三方式无法建立关联到该DNN和该S-NSSAI的PDU会话，则UE可尝试根据第二方式建立关联到该DNN和该S-NSSAI的PDU会话；如果根据第二方式无法建立关联到该DNN和该S-NSSAI的PDU会话，则UE可尝试根据第一方式建立关联到该DNN和该S-NSSAI的PDU会话。
示例性的，第一顺序可通过本地配置确定。或者，第一顺序可由第一网络设备指示，比如，UE注册到第二网络时，第一网络设备将第一顺序的指示信息发送至UE。或者，第一顺序可由部署于第一网络的第二网络设备指示，比如，UE注册到第一网络时，第二网络设备将第一顺序的指示信息发送至UE。
应理解，这里第一顺序的指示信息可包括以上第一方式、第二方式和第三方式分别的优先级。比如，该指示信息可携带第一方式的优先级、第二方式的优先级和第三方式的优先级。
或者，该指示信息可直接指示UE按照第三方式、第二方式和第一方式的顺序执行。
此外，该指示信息还可包括第一方式、第二方式和第三方式分别的信息，以指示第一方式、第二方式和第三方式。比如，指示信息指示第一方式、第二方式和第三方式分别对应的第一网络和第二网络之间的互通方式，比如，指示第一方式对于第一网络与第二网络之间不互通，以及指示第二方式对于第一网络与第二网络之间基于N3IWF互通，以及指示第三方式对于第一网络与第二网络之间基于漫游互通。再比如，该指示信息还可指示第一方式、第二方式和第三方式分别的切换方式，例如，指示第一方式为不互通切换方式，指示第二方式为N3IWF互通切换方式，以及指示第三方式为漫游互通切换方式。
另外，UE也可根据本地配置确定第一方式、第二方式和第三方式，比如，根据本地配置确定第一方式为不互通切换方式，根据本地配置确定第二方式为N3IWF互通切换方 式，以及根据本地配置确定第三方式为漫游互通切换方式。
应理解，以上第一顺序的指示信息仅仅是举例说明，具体实施中可通过以上多种方式中几种方式的组合实现，具体实现方式不应理解为以上述举例为限。
另外，第一网络设备和第二网络设备可通过其他方式指示第一方式、第二方式和第三方式执行上的先后顺序，比如，该指示信息包括第一方式、第二方式和第三方式分别的信息(比如第一方式、第二方式和第三方式分别对应的互通方式，或分别对应的PDU会话建立方式的信息)，该互通方式的排列顺序可代表第一方式、第二方式和第三方式分别的执行顺序。
在一种可能的实现时中，在图10和图14c所示流程的基础上，本申请实施例支持UE根据以下方法确定PDU会话的恢复方式：
在UE在第一网络建立关联到DNN和S-NSSAI的PDU会话，且UE注册到第二网络后，如果UE接收到来自于部署于第二网络的第一网络设备的第一信息，该第一信息可参照本申请实施例中对于第一信息的说明，则UE可根据该第一信息建立关联到该DNN和该S-NSSAI的PDU会话；否则，如果UE没有接收到来自于第二网络的第一信息，则可按照第三方式、第二方式和第一方式的顺序执行上述切换方法，以尝试建立关联到该DNN和该S-NSSAI的PDU会话，其中，该顺序即本申请实施例中的第一顺序。该第一顺序可由UE根据本地配置确定，或根据来自于第二网络设备的第一顺序的指示信息确定。
基于相同的构思，为了实现上述本申请实施例提供的方法中的各功能，本申请还提供一种通信装置。该通信装置可用于实现以上会话管理网元、用户面网元、策略管理网元、终端设备或接入网网元的功能。该通信装置可以包括硬件结构和/或软件模块，以硬件结构、软件模块、或硬件结构加软件模块的形式来实现上述各功能。上述各功能中的某个功能以硬件结构、软件模块、还是硬件结构加软件模块的方式来执行，取决于技术方案的特定应用和设计约束条件。
如图15所示，本申请实施例提供的一种通信装置可以包括通信模块1501以及处理模块1502，以上通信模块1501以及处理模块1502之间相互耦合。该通信装置1500可用于执行以上图3至图8中所示的由终端设备(UE)、第一网络设备(如图11至图13所示AMF#2)或SMF(或会话管理网元，例如图11和图12中的SMF#1或图13中的SMF#2)执行的步骤。该通信模块1501可用于支持通信装置1500进行通信，通信模块1501也可被称为通信单元、通信接口、收发模块或收发单元。通信模块1501可具备无线通信功能和/或有线通信功能。处理模块1502也可被称为处理单元，可用于支持该通信装置1500执行上述方法实施例中终端设备、第一网络设备或SMF的处理动作，包括但不限于：生成由通信模块1501发送的信息、消息，和/或，对通信模块1501接收的信号进行解调解码等等。
在执行图10至图13所示的由终端设备执行的动作时，通信模块1501可在第一网络建立关联到DNN和S-NSSAI的第一PDU会话，该通信模块1501还可向第一网络设备发送第一注册请求消息，该第一注册请求消息用于请求注册至第二网络。该通信模块1501还可接收来自于该第一网络设备的第一信息，该第一信息根据第一网络与该第二网络之间的互通方式确定。该通信模块1501还可根据该第一信息建立PDU会话，该PDU会话与该DNN和该S-NSSAI关联。
在一种可能的设计中，该第一注册请求消息中可包括跨非公网切换指示，用于指示该通信装置进行跨非公网切换。
在一种可能的设计中，以上第一网络与第二网络之间的互通方式包括第一网络与第二网络之间不互通、第一网络与第二网络之间基于N3IWF互通，或者，所述第一网络与所述第二网络之间基于漫游互通。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间不互通的情况下，该通信模块1501可向该第一网络设备发送第一PDU会话请求消息，该第一PDU会话请求消息包括值为initial request的request type信元，或者说，第一PDU会话请求消息用于请求建立初始PDU会话。该第一PDU会话请求消息包括该DNN的信息以及该S-NSSAI的信息，以请求建立关联至该DNN和该S-NSSAI的PDU会话。据此，在第一网络和第二网络不互通的方式下，UE可在第二网络新建关联至DNN和S-NSSAI的PDU会话，实现关联至该DNN和S-NSSAI的PDU会话的恢复，提高切换效率。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间不互通的情况下，该第一信息用于指示该第一网络与该第二网络之间不互通，或者，该第一信息用于指示该通信装置向该第一网络设备发送所述第一PDU会话请求。据此，可实现互通方式的灵活指示。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于N3IWF互通的情况下，该通信模块1501可向第一网络设备发送第二PDU会话请求消息，该第二PDU会话请求用于请求建立第二PDU会话。该通信模块1501还可通过第二PDU会话建立与N3IWF的连接，该N3IWF属于所述第一网络。该通信模块1501还可通过连接向第二网络设备发送第二注册请求消息，该第二注册请求消息用于请求通过N3GPP方式在第一网络注册，该第二网络设备属于该第一网络。该通信模块1501还可向第二网络设备发送第三PDU会话请求消息，该第三PDU会话请求消息包括值为existing PDU session的request type信元，或者说，第三PDU会话请求消息用于请求建立已有PDU会话。该第三PDU会话请求消息可携带该DNN的信息以及该S-NSSAI的信息。据此，在第一网络和第二网络基于N3IWF互通的方式下，UE可通过N3IWF和第二网络设备建立关联至该DNN的信息以及该S-NSSAI的第三PDU会话，实现UE的关联至该DNN和S-NSSAI的PDU会话的恢复，提高切换效率。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于N3IWF互通的情况下，第一信息可用于指示该第一网络与该第二网络之间基于N3IWF互通，或者用于指示向该第一网络设备发送该第二PDU会话请求、通过该N3IWF向该第二网络设备发送该第二注册请求，以及向该第二网络设备发送该第三PDU会话请求消息。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于漫游互通的情况下，该通信模块1501可向该第一网络设备发送第四PDU会话请求消息，该第四PDU会话请求消息包括值为existing PDU session的request type信元、该DNN的信息以及该S-NSSAI的信息。因此，在第一网络和第二网络基于漫游互通的方式下，UE可通过第一网络设备建立关联至该DNN的信息以及该S-NSSAI的第四PDU会话，实现UE的关联至该DNN和S-NSSAI的PDU会话的恢复，提高切换效率。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于漫游互通的情况下，该第一信息可用于指示第一网络与该第二网络之间基于漫游互通，或者用于指示向该第一网络设备发送该第四PDU会话请求消息。
在一种可能的设计中，该第四PDU会话请求消息中包括无损切换指示。因此，在互 通方式包括第一网络与第二网络之间基于漫游互通的情况下，可支持UE的无损网络切换。
在执行图10至图13所示的由第一网络设备执行的动作时，通信模块1501可接收来自于终端设备的第一注册请求消息，该通信装置属于第二网络，该第一注册请求消息用于请求注册至所述第二网络。处理模块1502可获取终端设备的上下文，并根据该上下文确定该终端设备已在第一网络注册。通信模块1501还可根据第一网络与第二网络之间的互通方式，向该终端设备发送第一信息。
在一种可能的设计中，处理模块1502还可根据该第一注册请求消息包括的跨非公网切换指示确定该终端设备进行跨非公网切换，该跨非公网切换指示用于指示所述终端设备进行跨非公网切换。或者，处理模块1502可根据该第一网络的标识确定该终端设备进行跨非公网切换，该第一网络的标识包括在所述上下文中。或者，处理模块1502可根据该第二网络设备的标识确定该终端设备进行跨非公网切换，该第二网络设备的标识包括在终端设备的上下文中。第二网络设备为终端设备在第一网络注册时接入的网络设备，如AMF。
在一种可能的设计中，通信模块1501可接收来自于第二网络设备的终端设备的上下文，该第二网络设备部署于第一网络中。通信模块1501可从UDM获取第二网络设备的信息，并请求该终端设备的上下文。
或者，通信模块1501可接收来自于数据存储节点的终端设备的上下文，数据存储节点由第一网络以及第二网络共用。
在一种可能的设计中，该数据存储节点包括UDM或AAA服务器。
在一种可能的设计中，以上第一网络与第二网络之间的互通方式包括第一网络与第二网络之间不互通、第一网络与第二网络之间基于N3IWF互通，或者，所述第一网络与所述第二网络之间基于漫游互通。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间不互通的情况下，第一信息可用于指示第一网络与第二网络之间不互通，或者，第一信息可用于指示终端设备向该通信装置发送第一PDU会话请求消息。该第一PDU会话请求消息包括值为initial request的request type信元，或者说，第一PDU会话请求消息用于请求建立初始PDU会话。此外，第一PDU会话请求消息还包括终端设备在第一网络建立的PDU会话所关联的DNN(或DNN的信息)以及PDU会话所关联的S-NSSAI(或S-NSSAI的信息)，或者说，第一信息还用于指示UE在第一PDU会话请求消息中携带终端设备在第一网络建立的PDU会话所关联的DNN的信息以及PDU会话所关联的S-NSSAI的信息。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于N3IWF互通的情况下，第一信息可用于指示第一网络与第二网络之间基于N3IWF互通。或者，第一信息可用于指示终端设备向该通信装置发送第二PDU会话请求消息、通过所述N3IWF向第二网络设备发送第二注册请求消息，以及向第二网络设备发送第三PDU会话请求消息。其中，第二PDU会话请求消息用于请求建立第二PDU会话，所述第二PDU会话用于建立所述终端设备与所述N3IWF之间的连接；所述第二注册请求消息用于请求通过N3GPP方式在所述第一网络注册；所述第三PDU会话请求消息包括值为existing PDU session的request type信元、所述终端设备在所述第一网络建立的PDU会话所关联的DNN的信息以及所述PDU会话所关联的S-NSSAI的信息。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于漫游互通的情况 下，第一信息可指示第一网络与第二网络之间基于漫游互通。或者，第一信息可指示终端设备向该通信装置发送第四PDU会话请求消息，该第四PDU会话请求消息包括值为existing PDU session的request type信元，或者说，第四PDU会话请求消息用于请求建立已有PDU会话。该第四PDU会话请求消息还包括终端设备在第一网络建立的PDU会话所关联的DNN的信息以及该PDU会话所关联的S-NSSAI的信息，或者说，第一信息还用于指示终端设备在第四PDU会话请求消息中携带终端设备在第一网络建立的PDU会话所关联的DNN的信息以及该PDU会话所关联的S-NSSAI的信息。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于漫游互通的情况下，通信模块1501还可接收来自于终端设备的上述第四PDU会话请求消息。通信模块1501还可向第一SMF发送所述第四PDU会话请求消息，其中，第一SMF为中间SMF，该第一SMF连接至第二SMF，该第二SMF维护终端设备在第一网络建立的关联至该DNN和该S-NSSAI的第一PDU会话，后续可由第一SMF将第四PDU会话请求消息转发至第二SMF，由第二SMF进行路径切换。或者，第一SMF属于第一网络，第一SMF维护终端设备在第一网络建立的关联至该DNN和该S-NSSAI的第一PDU会话。
在一种可能的设计中，通信模块1501还可向第一SMF发送跨非公网切换指示，所述跨非公网切换指示用于指示所述终端设备进行跨非公网切换。
在一种可能的设计中，该第四PDU会话请求中包括无损切换指示。
在执行图10至图13所示的由SMF执行的动作时，处理模块1502可建立终端设备的关联到DNN和S-NSSAI的第一PDU会话，该终端设备注册于第一网络。该第一PDU会话为第一接入网网元与第一UPF之间的PDU会话，该第一接入网网元属于该第一网络。通信模块1501可接收第四PDU会话请求消息，该第四PDU会话请求消息包括值为existing PDU session的request type信元，或者说，该第四PDU会话请求消息可用于请求建立已有PDU会话。该第四PDU会话请求消息还包括该DNN的信息以及该S-NSSAI的信息，以请求建立关联至该DNN和该S-NSSAI的PDU会话。通信模块1501还可向第一UPF发送第二信息，该第二信息用于指示第一UPF在第一PDU会话的路径切换后向该第一接入网网元发送结束标记，以及，用于指示该第一UPF将来自于该第一接入网网元的该终端设备的下行数据通过切换后的路径向该终端设备进行转发，该下行数据包括该结束标记。通信模块1501还可向第一接入网网元发送第三信息，该第三信息用于指示该第一接入网网元将该第一接入网网元缓存的该终端设备的下行数据转发至该第一UPF，直到接收并转发该结束标记。
在一种可能的设计中，该第四PDU会话请求消息包括无损切换指示，或者，可由处理模块1502根据本地配置确定针对该终端设备执行无损切换。
在一种可能的设计中，通信模块1501还可接收非公网切换指示。
在一种可能的设计中，以上第四PDU请求消息来自于第一网络设备，该第一网络设备属于第二网络，比如，此时该通信装置与第二网络，第一网络设备与该通信装置连接。或者，第四PDU会话请求消息由该第一网络设备发送至中间SMF，由中间SMF转发至该通信模块1501，比如，此时该通信装置不属于第二网络，第一网络设备与该通信装置不直接连接，需要通过中间SMF进行消息转发。
在执行图14c所示的由终端设备执行的动作时，通信模块1501可在第一网络建立关联到DNN和S-NSSAI的第一PDU会话，该通信模块1501还可向第一网络设备发送第一注册请求消息，该第一注册请求消息用于请求注册至第二网络。此外，通信模块1501可根据第一顺序建立(或请求建立)PDU会话，该PDU会话与该DNN和该S-NSSAI关联。其中，该第一顺序用于指示先后根据第三方式、第二方式和第一方式建立该PDU会话。或者说，处理模块1502按照第一顺序，先后通过通信模块1501按照第三方式、第二方式和第一方式建立(或请求建立)该PDU会话，直到建立该PDU会话。
在一种可能的设计中，第一注册请求消息中包括跨非公网切换指示，该跨非公网切换指示用于指示进行跨非公网切换。
在一种可能的设计中，在根据第一方式建立该PDU会话时，通信模块1501可向第一网络设备发送第一PDU会话请求消息，其中，该第一PDU会话请求消息包括值为initial request的request type信元，或者说，第一PDU会话请求消息用于请求建立初始PDU会话。该第一PDU会话请求消息包括该DNN的信息以及该S-NSSAI的信息，以请求建立关联至该DNN和该S-NSSAI的PDU会话。
在一种可能的设计中，通信模块1501可向第一网络设备发送第二PDU会话请求消息，该第二PDU会话请求用于请求建立第二PDU会话。通信模块1501可通过第二PDU会话建立与N3IWF的连接，该N3IWF属于该第一网络。通信模块1501通过该连接向第二网络设备发送第二注册请求消息，该第二注册请求消息用于请求通过N3GPP方式在第一网络注册，该第二网络设备属于该第一网络。在按照第二方式建立该PDU会话时，通信模块1501可向该第二网络设备发送第三PDU会话请求消息，该第三PDU会话请求消息包括值为existing PDU session的request type信元，或者说，该第三PDU会话请求消息可用于请求建立已有PDU会话。该第三PDU会话请求消息可包括该DNN的信息以及该S-NSSAI的信息。
在一种可能的设计中，在根据第三方式建立该PDU会话时，通信模块1501可向第一网络设备发送第四PDU会话请求消息，该第四PDU会话请求消息包括值为existing PDU session的request type信元，或者说，该第四PDU会话请求消息可用于请求建立已有PDU会话。该第四PDU会话请求消息还包括该DNN的信息以及该S-NSSAI的信息。
在一种可能的设计中，所述第四PDU会话请求消息中包括无损切换指示，以支持无损切换。
在一种可能的设计中，所述第一顺序为根据本地配置确定的。或者，通信模块1501可接收来自于第一网络设备的第一顺序的指示信息。可选的，该第一顺序的指示信息可根据第一网络设备的本地配置确定，或由第一网络设备根据第一网络和第二网络之间的互通方式确定。或者，通信模块1501可接收来自于第二网络设备的第一顺序的指示信息。可选的，该第一顺序的指示信息可根据第二网络设备的本地配置确定，或由第二网络设备根据第一网络和第二网络之间的互通方式确定。因此可灵活确定第一顺序。
此外，另一种可能的实现方式中，若通过硬件组件实现该会话管理网元，其结构还可如图16所示。为便于理解，图16中仅示出了执行本申请所示方法所必须的结构，本申请并不限制通信装置可具备更多组件。该通信装置1600可包括通信接口1601、存储器1602以及处理器1603。该通信接口1601可以用于通信装置进行通信，如用于通过有线和/或无线发送或接收信号，从而进行信息、数据和消息等的发送和/或接收。该存储器1602与所 述处理器1603耦合，其用于保存通信装置1600实现各功能所必要的程序和数据。该处理器1603被配置为支持通信装置1600执行上述方法中由会话管理网元执行的处理功能，如确定生成由通信接口1601发送的信息、消息，和/或，对通信接口1601接收的信号进行解调解码等等。以上存储器1602以及处理器1603可集成于一体也可相互独立。
示例性的，该通信接口1601可包括有线通信接口，可用于支持通信装置1600通过有线方式接收和发送信令和/或数据。通信接口1601也可被称为收发单元或通信单元。或者，该通信接口1601可包括无线收发器(如包括调制解调器和/或天线)，可用于支持通信装置1600通过无线方式接收和发送信令和/或数据。通信接口1601也可被称为无线收发器或无线通信单元。
该处理器1603可通过处理芯片或处理电路实现。
在执行图10至图13所示的由终端设备执行的动作时，通信接口1601可在第一网络建立关联到DNN和S-NSSAI的第一PDU会话，该通信接口1601还可向第一网络设备发送第一注册请求消息，该第一注册请求消息用于请求注册至第二网络。该通信接口1601还可接收来自于该第一网络设备的第一信息，该第一信息根据第一网络与该第二网络之间的互通方式确定。该通信接口1601还可根据该第一信息建立PDU会话，该PDU会话与该DNN和该S-NSSAI关联。
在一种可能的设计中，该第一注册请求消息中可包括跨非公网切换指示，用于指示该通信装置进行跨非公网切换。
在一种可能的设计中，以上第一网络与第二网络之间的互通方式包括第一网络与第二网络之间不互通、第一网络与第二网络之间基于N3IWF互通，或者，所述第一网络与所述第二网络之间基于漫游互通。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间不互通的情况下，该通信接口1601可向该第一网络设备发送第一PDU会话请求消息，该第一PDU会话请求消息包括值为initial request的request type信元，或者说，第一PDU会话请求消息用于请求建立初始PDU会话。该第一PDU会话请求消息包括该DNN的信息以及该S-NSSAI的信息，以请求建立关联至该DNN和该S-NSSAI的PDU会话。据此，在第一网络和第二网络不互通的方式下，UE可在第二网络新建关联至DNN和S-NSSAI的PDU会话，实现关联至该DNN和S-NSSAI的PDU会话的恢复，提高切换效率。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间不互通的情况下，该第一信息用于指示该第一网络与该第二网络之间不互通，或者，该第一信息用于指示该通信装置向该第一网络设备发送所述第一PDU会话请求。据此，可实现互通方式的灵活指示。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于N3IWF互通的情况下，该通信接口1601可向第一网络设备发送第二PDU会话请求消息，该第二PDU会话请求用于请求建立第二PDU会话。该通信接口1601还可通过第二PDU会话建立与N3IWF的连接，该N3IWF属于所述第一网络。该通信接口1601还可通过连接向第二网络设备发送第二注册请求消息，该第二注册请求消息用于请求通过N3GPP方式在第一网络注册，该第二网络设备属于该第一网络。该通信接口1601还可向第二网络设备发送第三PDU会话请求消息，该第三PDU会话请求消息包括值为existing PDU session的request type信元，或者说，第三PDU会话请求消息用于请求建立已有PDU会话。该第三PDU会话 请求消息可携带该DNN的信息以及该S-NSSAI的信息。据此，在第一网络和第二网络基于N3IWF互通的方式下，UE可通过N3IWF和第二网络设备建立关联至该DNN的信息以及该S-NSSAI的第三PDU会话，实现UE的关联至该DNN和S-NSSAI的PDU会话的恢复，提高切换效率。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于N3IWF互通的情况下，第一信息可用于指示该第一网络与该第二网络之间基于N3IWF互通，或者用于指示向该第一网络设备发送该第二PDU会话请求、通过该N3IWF向该第二网络设备发送该第二注册请求，以及向该第二网络设备发送该第三PDU会话请求消息。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于漫游互通的情况下，该通信接口1601可向该第一网络设备发送第四PDU会话请求消息，该第四PDU会话请求消息包括值为existing PDU session的request type信元、该DNN的信息以及该S-NSSAI的信息。因此，在第一网络和第二网络基于漫游互通的方式下，UE可通过第一网络设备建立关联至该DNN的信息以及该S-NSSAI的第四PDU会话，实现UE的关联至该DNN和S-NSSAI的PDU会话的恢复，提高切换效率。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于漫游互通的情况下，该第一信息可用于指示第一网络与该第二网络之间基于漫游互通，或者用于指示向该第一网络设备发送该第四PDU会话请求消息。
在一种可能的设计中，该第四PDU会话请求消息中包括无损切换指示。因此，在互通方式包括第一网络与第二网络之间基于漫游互通的情况下，可支持UE的无损网络切换。
在执行图10至图13所示的由第一网络设备执行的动作时，通信接口1601可接收来自于终端设备的第一注册请求消息，该通信装置属于第二网络，该第一注册请求消息用于请求注册至所述第二网络。处理器1603可获取终端设备的上下文，并根据该上下文确定该终端设备已在第一网络注册。通信接口1601还可根据第一网络与第二网络之间的互通方式，向该终端设备发送第一信息。
在一种可能的设计中，处理器1603还可根据该第一注册请求消息包括的跨非公网切换指示确定该终端设备进行跨非公网切换，该跨非公网切换指示用于指示所述终端设备进行跨非公网切换。或者，处理器1603可根据该第一网络的标识确定该终端设备进行跨非公网切换，该第一网络的标识包括在所述上下文中。或者，处理器1603可根据该第二网络设备的标识确定该终端设备进行跨非公网切换，该第二网络设备的标识包括在终端设备的上下文中。第二网络设备为终端设备在第一网络注册时接入的网络设备，如AMF。
在一种可能的设计中，通信接口1601可接收来自于第二网络设备的终端设备的上下文，该第二网络设备部署于第一网络中。通信接口1601可从UDM获取第二网络设备的信息，并请求该终端设备的上下文。
或者，通信接口1601可接收来自于数据存储节点的终端设备的上下文，数据存储节点由第一网络以及第二网络共用。
在一种可能的设计中，该数据存储节点包括UDM或AAA服务器。
在一种可能的设计中，以上第一网络与第二网络之间的互通方式包括第一网络与第二网络之间不互通、第一网络与第二网络之间基于N3IWF互通，或者，所述第一网络与所述第二网络之间基于漫游互通。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间不互通的情况下，第 一信息可用于指示第一网络与第二网络之间不互通，或者，第一信息可用于指示终端设备向该通信装置发送第一PDU会话请求消息。该第一PDU会话请求消息包括值为initial request的request type信元，或者说，第一PDU会话请求消息用于请求建立初始PDU会话。此外，第一PDU会话请求消息还包括终端设备在第一网络建立的PDU会话所关联的DNN(或DNN的信息)以及PDU会话所关联的S-NSSAI(或S-NSSAI的信息)，或者说，第一信息还用于指示UE在第一PDU会话请求消息中携带终端设备在第一网络建立的PDU会话所关联的DNN的信息以及PDU会话所关联的S-NSSAI的信息。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于N3IWF互通的情况下，第一信息可用于指示第一网络与第二网络之间基于N3IWF互通。或者，第一信息可用于指示终端设备向该通信装置发送第二PDU会话请求消息、通过所述N3IWF向第二网络设备发送第二注册请求消息，以及向第二网络设备发送第三PDU会话请求消息。其中，第二PDU会话请求消息用于请求建立第二PDU会话，所述第二PDU会话用于建立所述终端设备与所述N3IWF之间的连接；所述第二注册请求消息用于请求通过N3GPP方式在所述第一网络注册；所述第三PDU会话请求消息包括值为existing PDU session的request type信元、所述终端设备在所述第一网络建立的PDU会话所关联的DNN的信息以及所述PDU会话所关联的S-NSSAI的信息。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于漫游互通的情况下，第一信息可指示第一网络与第二网络之间基于漫游互通。或者，第一信息可指示终端设备向该通信装置发送第四PDU会话请求消息，该第四PDU会话请求消息包括值为existing PDU session的request type信元，或者说，第四PDU会话请求消息用于请求建立已有PDU会话。该第四PDU会话请求消息还包括终端设备在第一网络建立的PDU会话所关联的DNN的信息以及该PDU会话所关联的S-NSSAI的信息，或者说，第一信息还用于指示终端设备在第四PDU会话请求消息中携带终端设备在第一网络建立的PDU会话所关联的DNN的信息以及该PDU会话所关联的S-NSSAI的信息。
在一种可能的设计中，在互通方式包括第一网络与第二网络之间基于漫游互通的情况下，通信接口1601还可接收来自于终端设备的上述第四PDU会话请求消息。通信接口1601还可向第一SMF发送所述第四PDU会话请求消息，其中，第一SMF为中间SMF，该第一SMF连接至第二SMF，该第二SMF维护终端设备在第一网络建立的关联至该DNN和该S-NSSAI的第一PDU会话，后续可由第一SMF将第四PDU会话请求消息转发至第二SMF，由第二SMF进行路径切换。或者，第一SMF属于第一网络，第一SMF维护终端设备在第一网络建立的关联至该DNN和该S-NSSAI的第一PDU会话。
在一种可能的设计中，通信接口1601还可向第一SMF发送跨非公网切换指示，所述跨非公网切换指示用于指示所述终端设备进行跨非公网切换。
在一种可能的设计中，该第四PDU会话请求中包括无损切换指示。
在执行图10至图13所示的由SMF执行的动作时，处理器1603可建立终端设备的关联到DNN和S-NSSAI的第一PDU会话，该终端设备注册于第一网络。该第一PDU会话为第一接入网网元与第一UPF之间的PDU会话，该第一接入网网元属于该第一网络。通信接口1601可接收第四PDU会话请求消息，该第四PDU会话请求消息包括值为existing PDU session的request type信元，或者说，该第四PDU会话请求消息可用于请求建立已有PDU会话。该第四PDU会话请求消息还包括该DNN的信息以及该S-NSSAI的信息，以 请求建立关联至该DNN和该S-NSSAI的PDU会话。通信接口1601还可向第一UPF发送第二信息，该第二信息用于指示第一UPF在第一PDU会话的路径切换后向该第一接入网网元发送结束标记，以及，用于指示该第一UPF将来自于该第一接入网网元的该终端设备的下行数据通过切换后的路径向该终端设备进行转发，该下行数据包括该结束标记。通信接口1601还可向第一接入网网元发送第三信息，该第三信息用于指示该第一接入网网元将该第一接入网网元缓存的该终端设备的下行数据转发至该第一UPF，直到接收并转发该结束标记。
在一种可能的设计中，该第四PDU会话请求消息包括无损切换指示，或者，可由处理器1603根据本地配置确定针对该终端设备执行无损切换。
在一种可能的设计中，通信接口1601还可接收非公网切换指示。
在一种可能的设计中，以上第四PDU请求消息来自于第一网络设备，该第一网络设备属于第二网络，比如，此时该通信装置与第二网络，第一网络设备与该通信装置连接。或者，第四PDU会话请求消息由该第一网络设备发送至中间SMF，由中间SMF转发至该通信接口1601，比如，此时该通信装置不属于第二网络，第一网络设备与该通信装置不直接连接，需要通过中间SMF进行消息转发。
在执行图14c所示的由终端设备执行的动作时，通信接口1601可在第一网络建立关联到DNN和S-NSSAI的第一PDU会话，该通信接口1601还可向第一网络设备发送第一注册请求消息，该第一注册请求消息用于请求注册至第二网络。此外，通信接口1601可根据第一顺序建立(或请求建立)PDU会话，该PDU会话与该DNN和该S-NSSAI关联。其中，该第一顺序用于指示先后根据第三方式、第二方式和第一方式建立该PDU会话。或者说，处理器1603按照第一顺序，先后通过通信接口1601按照第三方式、第二方式和第一方式建立(或请求建立)该PDU会话，直到建立该PDU会话。
在一种可能的设计中，第一注册请求消息中包括跨非公网切换指示，该跨非公网切换指示用于指示进行跨非公网切换。
在一种可能的设计中，在根据第一方式建立该PDU会话时，通信接口1601可向第一网络设备发送第一PDU会话请求消息，其中，该第一PDU会话请求消息包括值为initial request的request type信元，或者说，第一PDU会话请求消息用于请求建立初始PDU会话。该第一PDU会话请求消息包括该DNN的信息以及该S-NSSAI的信息，以请求建立关联至该DNN和该S-NSSAI的PDU会话。
在一种可能的设计中，通信接口1601可向第一网络设备发送第二PDU会话请求消息，该第二PDU会话请求用于请求建立第二PDU会话。通信接口1601可通过第二PDU会话建立与N3IWF的连接，该N3IWF属于该第一网络。通信接口1601通过该连接向第二网络设备发送第二注册请求消息，该第二注册请求消息用于请求通过N3GPP方式在第一网络注册，该第二网络设备属于该第一网络。在按照第二方式建立该PDU会话时，通信接口1601可向该第二网络设备发送第三PDU会话请求消息，该第三PDU会话请求消息包括值为existing PDU session的request type信元，或者说，该第三PDU会话请求消息可用于请求建立已有PDU会话。该第三PDU会话请求消息可包括该DNN的信息以及该S-NSSAI的信息。
在一种可能的设计中，在根据第三方式建立该PDU会话时，通信接口1601可向第一网络设备发送第四PDU会话请求消息，该第四PDU会话请求消息包括值为existing PDU  session的request type信元，或者说，该第四PDU会话请求消息可用于请求建立已有PDU会话。该第四PDU会话请求消息还包括该DNN的信息以及该S-NSSAI的信息。
在一种可能的设计中，所述第四PDU会话请求消息中包括无损切换指示，以支持无损切换。
在一种可能的设计中，所述第一顺序为根据本地配置确定的。或者，通信接口1601可接收来自于第一网络设备的第一顺序的指示信息。可选的，该第一顺序的指示信息可根据第一网络设备的本地配置确定，或由第一网络设备根据第一网络和第二网络之间的互通方式确定。或者，通信接口1601可接收来自于第二网络设备的第一顺序的指示信息。可选的，该第一顺序的指示信息可根据第二网络设备的本地配置确定，或由第二网络设备根据第一网络和第二网络之间的互通方式确定。因此可灵活确定第一顺序。
基于与上述方法实施例相同构思，本申请实施例中还提供一种计算机可读存储介质，其上存储有计算机程序(或称指令)，该程序被处理器执行时，使该计算机执行上述方法实施例、方法实施例的任意一种可能的实现方式中由终端设备、第一网络设备和/或SMF执行的操作。
基于与上述方法实施例相同构思，本申请还提供一种计算机程序产品，该计算机程序产品在被计算机调用执行时，可以使得计算机实现上述方法实施例、方法实施例的任意一种可能的实现方式中由终端设备、第一网络设备和/或SMF执行的操作。
基于与上述方法实施例相同构思，本申请还提供一种芯片或芯片系统，该芯片与收发器耦合，用于实现上述方法实施例、方法实施例的任意一种可能的实现方式中由终端设备、第一网络设备和/或SMF执行的操作。该芯片系统可包括该芯片，以及包括存储器、通信接口等组件。
基于与上述方法实施例相同构思，本申请还提供一种通信系统，该通信系统可用于实现上述方法实施例、方法实施例的任意一种可能的实现方式中由终端设备、第一网络设备和/或SMF执行的操作。示例性的，该通信系统具有如图6至图9中任一所示结构。该通信系统可用于执行如图10至图14c中任一所示的流程。
本领域内的技术人员应明白，本申请的实施例可提供为方法、系统、或计算机程序产品。因此，本申请可采用完全硬件实施例、完全软件实施例、或结合软件和硬件方面的实施例的形式。而且，本申请可采用在一个或多个其中包含有计算机可用程序代码的计算机可用存储介质(包括但不限于磁盘存储器、CD-ROM、光学存储器等)上实施的计算机程序产品的形式。
本申请是参照根据本申请的方法、设备(系统)、和计算机程序产品的流程图和/或方框图来描述的。应理解可由计算机程序指令实现流程图和/或方框图中的每一流程和/或方框、以及流程图和/或方框图中的流程和/或方框的结合。可提供这些计算机程序指令到通用计算机、专用计算机、嵌入式处理机或其他可编程数据处理设备的处理器以产生一个机器，使得通过计算机或其他可编程数据处理设备的处理器执行的指令产生用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的装置。
这些计算机程序指令也可存储在能引导计算机或其他可编程数据处理设备以特定方式工作的计算机可读存储器中，使得存储在该计算机可读存储器中的指令产生包括指令装置的制造品，该指令装置实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能。
这些计算机程序指令也可装载到计算机或其他可编程数据处理设备上，使得在计算机或其他可编程设备上执行一系列操作步骤以产生计算机实现的处理，从而在计算机或其他可编程设备上执行的指令提供用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的步骤。
显然，本领域的技术人员可以对本申请进行各种改动和变型而不脱离本申请的保护范围。这样，倘若本申请的这些修改和变型属于本申请权利要求及其等同技术的范围之内，则本申请也意图包含这些改动和变型在内。

Claims (39)

  1. 一种通信方法，其特征在于，应用于终端设备，包括：
    注册于第一网络的终端设备在所述第一网络建立关联到数据网络名称DNN和单个网络切片选择辅助信息S-NSSAI的第一PDU会话；
    所述终端设备向第一网络设备发送第一消息，所述第一消息用于请求注册至所述第二网络；
    所述终端设备接收来自于所述第一网络设备的第一信息，所述第一信息根据第一网络与所述第二网络之间的互通方式确定；
    所述终端设备根据所述第一信息建立所述终端设备的协议数据单元PDU会话，所述PDU会话与所述DNN和所述S-NSSAI关联。
  2. 如权利要求1所述的方法，其特征在于，所述第一消息中包括跨非公网切换指示，所述跨非公网切换指示用于指示所述终端设备进行跨非公网切换。
  3. 如权利要求1或2所述的方法，其特征在于，所述互通方式包括：
    所述第一网络与所述第二网络之间不互通；或者，
    所述第一网络与所述第二网络之间基于非第三代合作伙伴计划互通功能网元N3IWF互通；或者，
    所述第一网络与所述第二网络之间基于漫游互通。
  4. 如权利要求1-3中任一所述的方法，其特征在于，所述互通方式包括所述第一网络与所述第二网络之间不互通，所述终端设备根据所述第一信息建立所述终端设备的PDU会话，包括：
    所述终端设备向所述第一网络设备发送第二消息，所述第二消息用于请求建立初始PDU会话，所述第二消息包括所述DNN的信息以及所述S-NSSAI的信息。
  5. 如权利要求4所述的方法，其特征在于，所述第一信息用于指示所述第一网络与所述第二网络之间不互通；或者，
    所述第一信息用于指示所述终端设备向所述第一网络设备发送所述第一PDU会话请求。
  6. 如权利要求1-3中任一所述的方法，其特征在于，所述互通方式包括所述第一网络与所述第二网络之间基于N3IWF互通，所述方法还包括：
    所述终端设备向所述第一网络设备发送第三消息，所述第三消息用于请求建立第二PDU会话；
    所述终端设备通过所述第二PDU会话建立与N3IWF的连接，所述N3IWF属于所述第一网络；
    所述终端设备通过所述连接向第二网络设备发送第四消息，所述第四消息用于请求通过N3GPP方式在所述第一网络注册，所述第二网络设备属于所述第一网络；
    所述终端设备根据所述第一信息建立所述终端设备的PDU会话，包括：
    所述终端设备向所述第二网络设备发送第五消息，所述第五消息用于请求建立已有PDU会话，所述第五消息包括所述DNN的信息以及所述S-NSSAI的信息。
  7. 如权利要求6所述的方法，其特征在于，所述第一信息用于指示所述第一网络与所述第二网络之间基于N3IWF互通；或者，
    所述第一信息用于指示所述终端设备向所述第一网络设备发送所述第三消息、通过所述N3IWF向所述第二网络设备发送所述第二注册请求，以及向所述第二网络设备发送所述第五消息。
  8. 如权利要求1-3中任一所述的方法，其特征在于，所述互通方式包括所述第一网络与所述第二网络之间基于漫游互通，所述终端设备根据所述第一信息恢复所述终端设备的关联到所述DNN和所述S-NSSAI的协议数据单元PDU会话，包括：
    所述终端设备向所述第一网络设备发送第六消息，所述第六消息用于请求建立已有PDU会话，所述第六消息包括所述DNN的信息以及所述S-NSSAI的信息。
  9. 如权利要求8所述的方法，其特征在于，所述第一信息用于指示所述第一网络与所述第二网络之间基于漫游互通；或者，
    所述第一信息用于指示所述终端设备向所述第一网络设备发送所述第六消息。
  10. 如权利要求8或9所述的方法，其特征在于，所述第六消息中包括无损切换指示。
  11. 一种通信方法，其特征在于，包括：
    第一网络设备接收来自于终端设备的第一消息，所述第一网络设备属于第二网络，所述第一消息用于请求注册至所述第二网络；
    所述第一网络设备获取终端设备的上下文；
    所述第一网络设备根据所述上下文确定所述终端设备已在第一网络注册；
    所述第一网络设备根据第一网络与第二网络之间的互通方式，向所述终端设备发送第一信息。
  12. 如权利要求11所述的方法，其特征在于，还包括：
    所述第一网络设备根据所述第一消息包括的跨非公网切换指示确定所述终端设备进行跨非公网切换，所述跨非公网切换指示用于指示所述终端设备进行跨非公网切换；或者，
    所述第一网络设备根据所述第一网络的标识确定所述终端设备进行跨非公网切换，所述第一网络的标识包括在所述上下文中；或者，
    所述第一网络设备根据第二网络设备的标识确定所述终端设备进行跨非公网切换，所述第二网络设备的标识包括在所述上下文中，所述第二网络设备属于所述第一网络。
  13. 如权利要求12所述的方法，其特征在于，所述第一网络设备获取终端的上下文，包括：
    所述第一网络设备接收来自于第二网络设备的所述终端设备的上下文，所述第二网络设备部署于所述第一网络中；或者，
    所述第一网络设备接收来自于数据存储节点的所述终端设备的上下文，所述数据存储节点由所述第一网络以及所述第二网络共用。
  14. 如权利要求13所述的方法，其特征在于，所述数据存储节点包括UDM或认证、授权、计费代理AAA服务器。
  15. 如权利要求11-14中任一所述的方法，其特征在于，所述互通方式包括：
    所述第一网络与所述第二网络之间不互通；或者，
    所述第一网络与所述第二网络之间基于N3IWF互通；或者，
    所述第一网络与所述第二网络之间基于漫游互通。
  16. 如权利要求11-15中任一所述的方法，其特征在于，所述互通方式包括所述第一网 络与所述第二网络之间不互通；
    所述第一信息用于指示所述第一网络与所述第二网络之间不互通；或者，
    所述第一信息用于指示所述终端设备向所述第一网络设备发送第二消息，所述第二消息用于请求建立初始PDU会话，所述第二消息包括所述终端设备在所述第一网络建立的PDU会话所关联的DNN的信息以及所述PDU会话所关联的S-NSSAI的信息。
  17. 如权利要求11-15中任一所述的方法，其特征在于，所述互通方式包括所述第一网络与所述第二网络之间基于N3IWF互通；
    所述第一信息用于指示所述第一网络与所述第二网络之间基于N3IWF互通；或者，
    所述第一信息用于指示所述终端设备向所述第一网络设备发送第三消息、通过所述N3IWF向所述第二网络设备发送第四消息，以及向所述第二网络设备发送第五消息；
    其中，所述第三消息用于请求建立第二PDU会话，所述第二PDU会话用于建立所述终端设备与所述N3IWF之间的连接；所述第四消息用于请求通过N3GPP方式在所述第一网络注册；所述第五消息用于请求建立已有PDU会话，所述第五消息包括所述终端设备在所述第一网络建立的PDU会话所关联的DNN的信息以及所述PDU会话所关联的S-NSSAI的信息。
  18. 如权利要求11-15中任一所述的方法，其特征在于，所述互通方式包括所述第一网络与所述第二网络之间基于漫游互通；
    所述第一信息用于指示所述第一网络与所述第二网络之间基于漫游互通；或者，
    所述第一信息用于指示所述终端设备向所述第一网络设备发送第六消息，所述第六消息用于请求建立已有PDU会话，所述第六消息包括所述终端设备在所述第一网络建立的PDU会话所关联的DNN的信息以及所述PDU会话所关联的S-NSSAI的信息。
  19. 如权利要求18所述的方法，其特征在于，所述方法还包括：
    所述第一网络设备接收所述第六消息；
    所述第一网络设备向第一会话管理功能SMF发送所述第六消息；
    所述第一SMF为中间SMF，所述第一SMF连接至第二SMF，所述第二SMF维护所述终端设备在第一网络建立的第一PDU会话，所述第一PDU会话关联至所述DNN以及所述S-NSSAI；或者，
    所述第一SMF属于所述第一网络，所述第一SMF维护所述终端设备在第一网络建立的第一PDU会话，所述第一PDU会话关联至所述DNN以及所述S-NSSAI。
  20. 如权利要求19所述的方法，其特征在于，所述方法还包括：
    所述第一网络设备向所述第一SMF发送跨非公网切换指示，所述跨非公网切换指示用于指示所述终端设备进行跨非公网切换。
  21. 如权利要求18-20中任一所述的方法，其特征在于，所述第六消息中包括无损切换指示。
  22. 一种通信方法，其特征在于，应用于终端设备，包括：
    注册于第一网络的所述终端设备在所述第一网络建立关联到DNN和S-NSSAI的第一PDU会话；
    所述终端设备向第一网络设备发送第一消息，所述第一消息用于请求注册至所述第二网络；
    所述终端设备根据第一顺序建立所述终端设备的PDU会话，所述PDU会话与所述 DNN和所述S-NSSAI关联；
    其中，所述第一顺序用于指示所述终端设备先后根据第三方式、第二方式和第一方式建立所述终端设备的PDU会话。
  23. 如权利要求22所述的方法，其特征在于，所述第一消息中包括跨非公网切换指示，所述跨非公网切换指示用于指示所述终端设备进行跨非公网切换。
  24. 如权利要求22或23所述的方法，其特征在于，所述终端设备根据第一方式建立所述终端设备的PDU会话，包括：
    所述终端设备向所述第一网络设备发送第二消息，所述第二消息用于请求建立初始PDU会话，所述第二消息包括所述DNN的信息以及所述S-NSSAI的信息。
  25. 如权利要求22-24中任一所述的方法，其特征在于，所述方法还包括：
    所述终端设备向所述第一网络设备发送第三消息，所述第三消息用于请求建立第二PDU会话；
    所述终端设备通过所述第二PDU会话建立与N3IWF的连接，所述N3IWF属于所述第一网络；
    所述终端设备通过所述连接向第二网络设备发送第四消息，所述第四消息用于请求通过N3GPP方式在第一网络注册，所述第二网络设备属于所述第一网络；
    所述终端设备根据第二方式建立所述终端设备的PDU会话，包括：
    所述终端设备向所述第二网络设备发送第五消息，所述第五消息用于请求建立已有PDU会话，所述第五消息包括所述DNN的信息以及所述S-NSSAI的信息。
  26. 如权利要求22-25中任一所述的方法，其特征在于，所述终端设备根据第三方式建立所述终端设备的PDU会话，包括：
    所述终端设备向所述第一网络设备发送第六消息，所述第六消息用于请求建立已有PDU会话，所述第六消息包括所述DNN的信息以及所述S-NSSAI的信息。
  27. 如权利要求26所述的方法，其特征在于，所述第六消息中包括无损切换指示。
  28. 如权利要求22或23所述的方法，其特征在于，所述第一顺序为根据本地配置确定的；或者，
    所述方法还包括：
    所述终端设备接收来自于所述第一网络设备的所述第一顺序的指示信息；或者，
    所述终端设备接收来自于所述第二网络设备的所述第一顺序的指示信息。
  29. 一种通信方法，其特征在于，应用于终端设备，包括：
    注册于第一网络的终端设备在所述第一网络建立关联到DNN和S-NSSAI的第一PDU会话；
    所述终端设备向第一网络设备发送第一消息，所述第一消息用于请求注册至所述第二网络；
    所述终端设备接收来自于所述第一网络设备的第一信息，所述第一信息根据第一网络与所述第二网络之间的互通方式确定，所述第一网络与所述第二网络之间不漫游互通；
    所述终端设备根据所述第一信息确定按照支持N3WIF的方式恢复所述终端设备的PDU会话，或确定不再建立所述终端设备的PDU会话，所述PDU会话与所述DNN和所述S-NSSAI关联。
  30. 如权利要求29所述的方法，其特征在于，所述终端设备根据所述第一信息确定按照支持N3WIF的方式恢复所述终端设备的PDU会话，包括：
    所述终端设备向所述第一网络设备发送第三消息，所述第三消息用于请求建立第二PDU会话；
    所述终端设备通过所述第二PDU会话建立与N3IWF的连接，所述N3IWF属于所述第一网络；
    所述终端设备通过所述连接向第二网络设备发送第四消息，所述第四消息用于请求通过N3GPP方式在所述第一网络注册，所述第二网络设备属于所述第一网络；
    所述终端设备根据所述第一信息建立所述终端设备的PDU会话，包括：
    所述终端设备向所述第二网络设备发送第五消息，所述第五消息用于请求建立已有PDU会话，所述第五消息包括所述DNN的信息以及所述S-NSSAI的信息。
  31. 如权利要求30所述的方法，其特征在于，所述第一信息用于指示所述第一网络与所述第二网络之间不支持漫游互通。
  32. 一种通信方法，其特征在于，包括：
    第一网络设备接收来自于终端设备的第一消息，所述第一网络设备属于第二网络，所述第一消息用于请求注册至所述第二网络；
    所述第一网络设备获取终端设备的标识，确定第一网络的标识；
    所述第一网络设备根据第一网络与第二网络之间是否支持漫游互通方式，向所述终端设备发送第一信息。
  33. 一种通信装置，其特征在于，包括处理器以及通信接口；
    所述通信接口可用于支持所述通信装置进行通信；
    所述处理器可用于执行指令，实现如权利要求1-10中任一所述的方法。
  34. 一种通信装置，其特征在于，包括处理器以及通信接口；
    所述通信接口可用于支持所述通信装置进行通信；
    所述处理器可用于执行指令，实现如权利要求11-21中任一所述的方法。
  35. 一种通信装置，其特征在于，包括处理器以及通信接口；
    所述通信接口可用于支持所述通信装置进行通信；
    所述处理器可用于执行指令，实现如权利要求22-28中任一所述的方法。
  36. 一种通信装置，其特征在于，包括处理器以及通信接口；
    所述通信接口可用于支持所述通信装置进行通信；
    所述处理器可用于执行指令，实现如权利要求29-31中任一所述的方法。
  37. 一种通信装置，其特征在于，包括处理器以及通信接口；
    所述通信接口可用于支持所述通信装置进行通信；
    所述处理器可用于执行指令，实现如权利要求32所述的方法。
  38. 一种通信系统，其特征在于，包括如权利要求33及34所述的通信装置，或包括如权利要求35所述的通信装置和第一网络设备，或包括如权利要求36和37所述的通信装置。
  39. 一种计算机可读存储介质，所述计算机存储介质中存储有指令，其特征在于，当所述指令在计算机上被调用执行时，使得计算机执行如权利要求1-32中任一所述的方法。
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