CN116325832A

CN116325832A - Session management method, terminal equipment and network equipment

Info

Publication number: CN116325832A
Application number: CN202080105708.7A
Authority: CN
Inventors: 杨皓睿; 付喆
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2020-11-10
Filing date: 2020-11-10
Publication date: 2023-06-23
Also published as: WO2022099475A1

Abstract

The application relates to a session management method, terminal equipment and network equipment. Wherein the method may comprise: in the case that the terminal equipment leaves a first cell supporting first slice information and enters a second cell not supporting the first slice information, the terminal equipment receives second slice information supported by the second cell; the terminal device releases the session using the first slicing information; the terminal device establishes a session using the second slice information. According to the embodiment of the application, when the terminal equipment leaves the first cell supporting the first slice information and enters the second cell not supporting the first slice information, the terminal equipment receives the second slice information supported by the second cell, so that the session using the first slice information can be released, and the session is established by using the second slice information, thereby being beneficial to maintaining the service continuity of the terminal equipment.

Description

Session management method, terminal equipment and network equipment

Technical Field

The present invention relates to the field of communications, and more particularly, to a session management method, a terminal device, and a network device.

Background

Network slices may be deployed in a fifth Generation communication (5 th-Generation) network. The network slice may be identified using Single network slice selection assistance information (Single-Network Slice Selection Assistance Information, S-nsai). The set of S-nsais is referred to as network slice selection assistance information (Network Slice Selection Assistance Information, nsai). When a User Equipment (UE) needs to use a network slice, the UE needs to request the network to use the slice, and after the network agrees, a Packet Data Unit (PDU) session is established in the slice to transmit Data. At the time of network deployment, base stations of different areas may support different network slices. How to guarantee traffic continuity is a matter of consideration when the UE moves to an area supporting different network slices.

Disclosure of Invention

The embodiment of the application provides a session management method, terminal equipment and network equipment, which can keep the service continuity of the terminal equipment.

The embodiment of the application provides a session management method, which comprises the following steps:

in the case that the terminal equipment leaves a first cell supporting first slice information and enters a second cell not supporting the first slice information, the terminal equipment receives second slice information supported by the second cell;

The terminal device releases the session using the first slicing information;

the terminal device establishes a session using the second slice information.

The embodiment of the application provides a method for transmitting second slice information supported by a second cell to terminal equipment by network equipment when the terminal equipment leaves a first cell supporting first slice information and enters the second cell not supporting the first slice information.

The embodiment of the application provides a terminal device, which comprises:

a receiving unit, configured to receive second slice information supported by a second cell when a terminal device leaves a first cell supporting first slice information and enters the second cell not supporting the first slice information;

a releasing unit for releasing a session using the first slice information;

and the establishing unit is used for establishing a session by using the second slice information.

The embodiment of the application provides a network device, which comprises:

and a transmitting unit, configured to transmit second slice information supported by a second cell to the terminal device, where the terminal device leaves the first cell supporting the first slice information and enters the second cell not supporting the first slice information.

The embodiment of the application provides terminal equipment, which comprises a processor and a memory. The memory is used for storing a computer program, and the processor is used for calling and running the computer program stored in the memory so as to enable the terminal equipment to execute the session management method.

The embodiment of the application provides a network device, which comprises a processor and a memory. The memory is used for storing a computer program, and the processor is used for calling and running the computer program stored in the memory so as to enable the network equipment to execute the session management method.

The embodiment of the application provides a chip for realizing the session management method.

Specifically, the chip includes: and a processor for calling and running the computer program from the memory, so that the device mounted with the chip executes the session management method.

The embodiment of the application provides a computer readable storage medium for storing a computer program which, when executed by a device, causes the device to perform the session management method described above.

Embodiments of the present application provide a computer program product comprising computer program instructions for causing a computer to perform the above-described session management method.

The embodiment of the application provides a computer program which, when run on a computer, causes the computer to execute the session management method.

According to the embodiment of the application, when the terminal equipment leaves the first cell supporting the first slice information and enters the second cell not supporting the first slice information, the terminal equipment receives the second slice information supported by the second cell, so that the session using the first slice information can be released, and the session is established by using the second slice information, thereby being beneficial to maintaining the service continuity of the terminal equipment.

Drawings

Fig. 1 is a schematic diagram of an application scenario according to an embodiment of the present application.

Fig. 2 is a schematic diagram of an exemplary 5G network system architecture.

Fig. 3 is a schematic diagram of an exemplary network slice.

Fig. 4 is a schematic flow chart of a session management method according to an embodiment of the present application.

Fig. 5 is a schematic flow chart diagram of a session management method according to another embodiment of the present application.

Fig. 6 is a schematic flow chart diagram of a session management method according to another embodiment of the present application.

Fig. 7 is a schematic flow chart diagram of a session management method according to another embodiment of the present application.

Fig. 8 is a schematic block diagram of a terminal device according to an embodiment of the present application.

Fig. 9 is a schematic block diagram of a terminal device according to another embodiment of the present application.

Fig. 10 is a schematic block diagram of a network device according to an embodiment of the present application.

Fig. 11 is a schematic block diagram of a network device according to another embodiment of the present application.

Fig. 12 is a schematic block diagram of a communication device according to an embodiment of the present application.

Fig. 13 is a schematic block diagram of a chip according to an embodiment of the present application.

Fig. 14 is a schematic block diagram of a communication system according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.

The technical solution of the embodiment of the application can be applied to various communication systems, for example: global system for mobile communications (Global System of Mobile communication, GSM), code division multiple access (Code Division Multiple Access, CDMA) system, wideband code division multiple access (Wideband Code Division Multiple Access, WCDMA) system, general packet Radio service (General Packet Radio Service, GPRS), long term evolution (Long Term Evolution, LTE) system, advanced long term evolution (Advanced long term evolution, LTE-a) system, new Radio (NR) system, evolved system of NR system, LTE-based access to unlicensed spectrum, LTE-U) system on unlicensed spectrum, NR (NR-based access to unlicensed spectrum, NR-U) system on unlicensed spectrum, non-terrestrial communication network (Non-Terrestrial Networks, NTN) system, universal mobile communication system (Universal Mobile Telecommunication System, UMTS), wireless local area network (Wireless Local Area Networks, WLAN), wireless fidelity (Wireless Fidelity, wiFi), fifth Generation communication (5 th-Generation, 5G) system, or other communication system, etc.

Generally, the number of connections supported by the conventional communication system is limited and easy to implement, however, with the development of communication technology, the mobile communication system will support not only conventional communication but also, for example, device-to-Device (D2D) communication, machine-to-machine (Machine to Machine, M2M) communication, machine type communication (Machine Type Communication, MTC), inter-vehicle (Vehicle to Vehicle, V2V) communication, or internet of vehicles (Vehicle to everything, V2X) communication, etc., and the embodiments of the present application may also be applied to these communication systems.

Optionally, the communication system in the embodiment of the present application may be applied to a carrier aggregation (Carrier Aggregation, CA) scenario, a dual connectivity (Dual Connectivity, DC) scenario, and a Stand Alone (SA) fabric scenario.

Optionally, the communication system in the embodiments of the present application may be applied to unlicensed spectrum, where unlicensed spectrum may also be considered as shared spectrum; alternatively, the communication system in the embodiments of the present application may also be applied to licensed spectrum, where licensed spectrum may also be considered as non-shared spectrum.

Embodiments of the present application describe various embodiments in connection with network devices and terminal devices, where a terminal device may also be referred to as a User Equipment (UE), access terminal, subscriber unit, subscriber station, mobile station, remote terminal, mobile device, user terminal, wireless communication device, user agent, user Equipment, or the like.

The terminal device may be a Station (ST) in a WLAN, may be a cellular telephone, a cordless telephone, a session initiation protocol (Session Initiation Protocol, SIP) phone, a wireless local loop (Wireless Local Loop, WLL) station, a personal digital assistant (Personal Digital Assistant, PDA) device, a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, a vehicle device, a wearable device, a terminal device in a next generation communication system such as an NR network, or a terminal device in a future evolved public land mobile network (Public Land Mobile Network, PLMN) network, etc.

In embodiments of the present application, the terminal device may be deployed on land, including indoor or outdoor, hand-held, wearable or vehicle-mounted; can also be deployed on the water surface (such as ships, etc.); but may also be deployed in the air (e.g., on aircraft, balloon, satellite, etc.).

In the embodiment of the present application, the terminal device may be a Mobile Phone (Mobile Phone), a tablet computer (Pad), a computer with a wireless transceiving function, a Virtual Reality (VR) terminal device, an augmented Reality (Augmented Reality, AR) terminal device, a wireless terminal device in industrial control (industrial control), a wireless terminal device in unmanned driving (self driving), a wireless terminal device in remote medical (remote medical), a wireless terminal device in smart grid (smart grid), a wireless terminal device in transportation security (transportation safety), a wireless terminal device in smart city (smart city), or a wireless terminal device in smart home (smart home), and the like.

By way of example, and not limitation, in embodiments of the present application, the terminal device may also be a wearable device. The wearable device can also be called as a wearable intelligent device, and is a generic name for intelligently designing daily wear by applying wearable technology and developing wearable devices, such as glasses, gloves, watches, clothes, shoes and the like. The wearable device is a portable device that is worn directly on the body or integrated into the clothing or accessories of the user. The wearable device is not only a hardware device, but also can realize a powerful function through software support, data interaction and cloud interaction. The generalized wearable intelligent device includes full functionality, large size, and may not rely on the smart phone to implement complete or partial functionality, such as: smart watches or smart glasses, etc., and focus on only certain types of application functions, and need to be used in combination with other devices, such as smart phones, for example, various smart bracelets, smart jewelry, etc. for physical sign monitoring.

In this embodiment of the present application, the network device may be a device for communicating with a mobile device, where the network device may be an Access Point (AP) in WLAN, a base station (Base Transceiver Station, BTS) in GSM or CDMA, a base station (NodeB, NB) in WCDMA, an evolved base station (Evolutional Node B, eNB or eNodeB) in LTE, a relay station or an Access Point, a vehicle device, a wearable device, and a network device (gNB) in an NR network, or a network device in a PLMN network for future evolution, or a network device in an NTN network, etc.

By way of example and not limitation, in embodiments of the present application, a network device may have a mobile nature, e.g., the network device may be a mobile device. Alternatively, the network device may be a satellite, a balloon station. For example, the satellite may be a Low Earth Orbit (LEO) satellite, a medium earth orbit (medium earth orbit, MEO) satellite, a geosynchronous orbit (geostationary earth orbit, GEO) satellite, a high elliptical orbit (High Elliptical Orbit, HEO) satellite, or the like. Alternatively, the network device may be a base station disposed on land, in a water area, or the like.

In this embodiment of the present application, a network device may provide a service for a cell, where a terminal device communicates with the network device through a transmission resource (e.g., a frequency domain resource, or a spectrum resource) used by the cell, where the cell may be a cell corresponding to a network device (e.g., a base station), and the cell may belong to a macro base station, or may belong to a base station corresponding to a Small cell (Small cell), where the Small cell may include: urban cells (Metro cells), micro cells (Micro cells), pico cells (Pico cells), femto cells (Femto cells) and the like, and the small cells have the characteristics of small coverage area and low transmitting power and are suitable for providing high-rate data transmission services.

Fig. 1 schematically illustrates a communication system 100. The communication system comprises one network device 110 and two terminal devices 120. Alternatively, the communication system 100 may include a plurality of network devices 110, and the coverage area of each network device 110 may include other numbers of terminal devices 120, which are not limited in this embodiment of the present application.

Optionally, the communication system 100 may further include other network entities such as a mobility management entity (Mobility Management Entity, MME), an access and mobility management function (Access and Mobility Management Function, AMF), and the embodiment of the present application is not limited thereto.

The network device may further include an access network device and a core network device. I.e. the wireless communication system further comprises a plurality of core networks for communicating with the access network devices. The access network device may be a long-term evolution (LTE) system, a next-generation (NR) system, or an evolved base station (evolutional node B, abbreviated as eNB or e-NodeB) macro base station, a micro base station (also called "small base station"), a pico base station, an Access Point (AP), a transmission point (transmission point, TP), a new generation base station (new generation Node B, gNodeB), or the like in an licensed assisted access long-term evolution (LAA-LTE) system.

It should be understood that a device having a communication function in a network/system in an embodiment of the present application may be referred to as a communication device. Taking the communication system shown in fig. 1 as an example, the communication device may include a network device and a terminal device with a communication function, where the network device and the terminal device may be specific devices in the embodiments of the present application, and are not described herein again; the communication device may also include other devices in the communication system, such as a network controller, a mobility management entity, and other network entities, which are not limited in this embodiment of the present application.

It should be understood that the terms "system" and "network" are used interchangeably herein. The term "and/or" is herein merely an association relationship describing an associated object, meaning that there may be three relationships, e.g., a and/or B, may represent: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.

It should be understood that, in the embodiments of the present application, the "indication" may be a direct indication, an indirect indication, or an indication having an association relationship. For example, a indicates B, which may mean that a indicates B directly, e.g., B may be obtained by a; it may also indicate that a indicates B indirectly, e.g. a indicates C, B may be obtained by C; it may also be indicated that there is an association between a and B.

In the description of the embodiments of the present application, the term "corresponding" may indicate that there is a direct correspondence or an indirect correspondence between the two, or may indicate that there is an association between the two, or may indicate a relationship between the two and the indicated, configured, or the like.

In order to facilitate understanding of the technical solutions of the embodiments of the present application, the following description is given of related technologies of the embodiments of the present application, and the following related technologies may be optionally combined with the technical solutions of the embodiments of the present application as an alternative, which all belong to the protection scope of the embodiments of the present application.

Fig. 2 exemplarily shows a 5G network system architecture. The UE performs Access stratum connection with AN Access Network (AN) through a Uu wireless interface, interacts Access stratum messages and wireless data transmission, and performs non-Access stratum (NAS, none Access Stratum) connection with AN Access and mobility management function (AMF, access and Mobility Management Function) through AN N1 interface, and interacts NAS messages. The AMF is responsible for access and mobility management network elements in the core network, session management functions (SMF, session Management Function) are responsible for session management network elements in the core network, and the AMF is responsible for forwarding session management related messages between the UE and the SMF in addition to mobility management of the UE. The policy control function (PCF, policy Control Function) is a policy management function in the core network, responsible for formulating policies related to mobility management, session management, charging, etc. for the UE. The user plane function (UPF, user Plane Function) is a user plane function in the core network, and performs data transmission with the external data network through the N6 interface, and performs data transmission with the AN (or RAN) through the N3 interface.

And after the UE accesses the 5G network through the Uu port, the UE transmits service data through the network. When a service is initiated, a network layer of the UE obtains a QoS requirement of the service from an upper layer (e.g., an operating system or an application), the UE converts the QoS requirement of the service into a QoS parameter of a Uu interface, and performs data transmission through a corresponding QoS flow between the UE and the UPF under the control of the SMF.

In a network slice application scenario, a UE places an S-nsai to be Requested in a Requested (Requested) nsai according to traffic, and the Requested nsai is included in a registration request (Registration request) and sent to an AMF. The AMF determines the Allowed (Allowed) nsai according to the scope of UE subscription and network slice deployment, and sends the Allowed (Allowed) nsai to the UE in a registration accept (Registration accept) message, or sends the Allowed (Allowed) nsai to the base station RAN (Radio Access Network ) in an N2 interface message.

After receiving the allowed nsai, the UE needs to establish a PDU session in the slice in the allowed nsai. The PDU session establishment is completed before data can be transmitted and received.

The coverage of each slice may be different at the time of network deployment. The AMF, when deciding the allowed nsai, needs to ensure that all slices in the allowed nsai can be covered by the registration area (Registration area, RA) that the AMF allocates to the UE. For example, the RA may be a tracking area list (TA list) consisting of one or more TAs. The AMF obtains S-nsai and corresponding Tracking Area (TA) supported by the base station from the base station through NG setup request (setup request) or RAN configuration update (configuration update) signaling.

As shown in the following table, an example of slice information that the base station informs the AMF of itself to be currently supported is provided.

For example, in one application scenario, base stations in different areas may support different network slices. As shown in fig. 3, the RA of a certain region and the UE may not coincide completely. Cell 1 supports slice 1 and cell 2 supports slice 2. When a UE moves from cell 1 to cell 2, since cell 2 does not support slice 1, slice 1 may be mapped to slice 2, and slice 2 is used to serve the UE to ensure traffic continuity.

Illustratively, the traffic continuity (Service and Session Continuity, SSC) may include a plurality of modes (modes). For example SSC mode 1, 2, 3. Wherein, SSC mode 1 may refer to an Anchor (Anchor) UPF used for a PDU session (session) being unchanged, and a PDU address, for example, an internet protocol (Internet Protocol, IP) address being unchanged; the SSC mode 2 may refer to releasing the old PDU session first, then establishing a new PDU session, changing the Anchor UPF, and changing the PDU address; the SSC mode 3 may refer to that a new PDU session is established first, then an old PDU session is released, an Anchor UPF is changed, and a PDU address is changed. SSC modes 2 and 3 can pass over the PDU layer, for example: transmission control protocol (TCP, transmission Control Protocol) layer protocol to achieve service continuity, making interruption of service imperceptible to the user. In the embodiment of the application, different service continuity can be ensured aiming at the scene.

Fig. 4 is a schematic flow chart diagram of a session management method 200 according to an embodiment of the present application. The method may alternatively be applied to the systems shown in fig. 1, 2, 3, for example, but is not limited thereto. The method includes at least some of the following.

S210, in a case that the terminal device leaves the first cell supporting the first slice information and enters the second cell not supporting the first slice information, the terminal device receives the second slice information supported by the second cell.

S220, the terminal equipment releases the session using the first slice information.

S230, the terminal equipment establishes a session by using the second slice information.

Illustratively, in case the terminal device is in the first cell, performing a registration procedure, obtaining allowed slice information, e.g. first slice information, a PDU session may be established using the first slice information supported by the first cell. If the terminal equipment leaves the first cell and enters the second cell, a switching flow between the first access network equipment corresponding to the first cell and the second access network equipment corresponding to the second cell can be triggered. Wherein if the second cell does not support the first slicing information, the PDU session established by the terminal device using the first slicing information cannot be successfully handed over to the second access network device. During or after the handover, the first access network device or the second access network device may inform the first core network device, e.g. the AMF, that the session has not been successfully handed over. The notification can also carry the mapping relation between the first slice information and the second slice information; and/or, second slice information and mapping indication. If the AMF knows the mapping relationship between the first slice information and the second slice information, for example, the mapping relationship is preconfigured on the AMF, the notification may not carry the above information.

The terminal device may receive the second handover information if the second cell supports the second slice information. The terminal device may then release the PDU session of the first slice information locally and establish the PDU session using the second slice information.

Optionally, the first slice information and the second slice information have a mapping relationship.

Optionally, the method further comprises:

and under the condition that the terminal equipment moves to the second cell, the terminal equipment acquires slice information supported by the access network equipment from a system message broadcasted by the access network equipment corresponding to the second cell.

In an exemplary embodiment, if the first access network device corresponding to the first cell is an original base station, the second access network device corresponding to the second cell is a target base station, and the terminal device moves to the second cell, slice information supported by the target base station may be obtained from a system message broadcasted by the target corresponding to the second cell.

Optionally, the method further comprises:

the radio resource control (Radio Resource Control, RRC) layer of the terminal device transfers slice information supported by the Access network device to a Non-Access-Stratum (NAS) layer of the terminal device to determine whether the first slice information is available (available) at the NAS layer.

Optionally, the terminal device releases the session using the first slice information, and further includes:

the terminal device receives a PDU session release command sent from the network, or, in case it is determined that the first slice information is not available, the terminal device locally releases a PDU session using the first slice information.

Optionally, after the handover procedure is completed, the terminal device executes a new registration procedure under a trigger condition that satisfies the registration procedure.

Optionally, the triggering condition includes at least one of:

the terminal device leaves the registration area;

a first core network device, such as an AMF, changes;

the terminal device discovers that the second cell does not support the allowed nsais saved for the registered PLMN.

For example, after the handover is completed, the terminal device leaves the registration area obtained before, and may trigger the registration procedure. For another example, if the AMF of the cell into which the terminal device enters changes, the registration procedure may be triggered. In addition, if the terminal device acquires slice information supported by the target base station from a system message corresponding to the target broadcast of the second cell, then discovers that the second cell does not support allowed NSSAI stored for the registered PLMN. The conditions for triggering the registration procedure are various, and the embodiment of the present application is not specifically limited.

Optionally, in the registration procedure, the terminal device sends a registration request for instructing the first core network device, e.g. the AMF, to release the PDU session using the first slice information.

Optionally, the registration request does not include the requested first slice information.

In an exemplary embodiment, the terminal device sends a registration request to the AMF through the access network device, where the registration request may not include the first slice information, and after the AMF receives the registration request, it determines that the first slice information is no longer requested by the terminal device, and may trigger the SMF to release the PDU session using the first slice information. The registration request may also include first slice information, where the AMF may be capable of obtaining the current cell of the terminal device or the current TA does not support the first slice information in other manners, and may trigger the SMF to release the PDU session using the first slice information.

Alternatively, the AMF may inform the SMF that the PDU session using the first slice information needs to be released. For example, the AMF sends a session release message to the SMF, where the session release message includes an identification of the PDU session that needs to be released. After the SMF receives the session release message, the session corresponding to the identifier of the PDU session therein, that is, the PDU session using the first slice information, may be released.

Optionally, at least one of the following may be further included in the session release message:

mapping relation between the first slice information and the second slice information;

second slice information and mapping indication.

Optionally, in one manner, the second slice information received by the terminal device is carried by a first NAS message, where the first NAS message is sent by the first core network device to the terminal device with the second slice information and a second NAS message from the second core network device.

Optionally, the first core network device is an access and mobility management network element AMF, and the second core network device is a session management network element SMF.

Optionally, the second slice information is included in the second NAS message.

Optionally, the second NAS message is a PDU session release order.

Illustratively, after the SMF decides to release the PDU session, a second NAS message may be sent to the AMF, in which the identity of the PDU session, etc. may be included. The second NAS message may further include second slice information if the SMF knows a mapping relationship of the first slice information and the second slice information, or the second slice information and the mapping indication. The AMF may then send the first NAS message to the terminal device through the first access network device or the second access network device, and send the second slice information to the terminal device.

Optionally, in another manner, the second slice information received by the terminal device is carried through a registration acceptance message, where the registration acceptance message includes at least one of the following:

the first slice information is mapped to the second slice information;

the allowed slice information is the second slice information.

Alternatively, in this manner, the access network device may notify the AMF of the mapping relationship between the first slice information and the second slice information before the terminal device performs the new registration procedure. For example, before the terminal device performs an initial registration procedure, the access network device notifies the AMF of the mapping relationship between the first slice information and the second slice information. For another example, during or after the handover, the access network device notifies the AMF of the mapping relationship between the first slice information and the second slice information.

Optionally, the first slice information and/or the second slice information selects auxiliary information S-nsai for a single network slice.

For example, the first handover information is S-nsai 1, the second handover information is S-nsai 2, the first cell and its corresponding first access network device support S-nsai 1, and the second cell and its corresponding second access network device support S-nsai 2 without supporting S-nsai 1. In case the terminal device leaves the first cell and enters the second cell, the terminal device receives S-nsai 2. The terminal device releases the PDU session using S-NSSAI 1 and establishes the PDU session using S-NSSAI 2.

Fig. 5 is a schematic flow chart diagram of a session management method 300 according to an embodiment of the present application. The method may alternatively be applied to the systems shown in fig. 1, 2, 3, for example, but is not limited thereto. The method includes at least some of the following.

S310, when the terminal device leaves the first cell supporting the first slice information and enters the second cell not supporting the first slice information, the network device sends the second slice information supported by the second cell to the terminal device.

Alternatively, the network device in this embodiment may be a first core network device, for example, an AMF, and specifically, reference may be made to the description about the first core network device in the foregoing embodiment.

Optionally, the method further comprises:

the network device receives a notification from the access network device that the PDU session established using the first slice information in the handover procedure cannot be successfully handed over. For example, the first core network device AMF receives a notification from the original base station or the target base station to learn that the PDU session established using the first slice information in the handover procedure cannot be successfully handed over from the original base station to the target base station.

Optionally, the notification includes at least one of:

second slice information and mapping indication.

Optionally, the method further comprises:

the network device receives a mapping relationship of the first slice information and the second slice information from the access network device. For example, the first core network device AMF receives a mapping relationship between the first slice information and the second slice information from the original base station or the target base station.

Optionally, the method further comprises:

the network device sends a session release message to the core network device, where the session release message includes an identifier of a PDU session to be released, and the session release message is used to instruct the core network device to release the PDU session using the first slice information.

Optionally, the core network device, e.g. the second core network device, is an SMF.

Illustratively, the first core network device, e.g., the AMF, sends a session release message to the second core network device, e.g., the SMF.

Optionally, the session release message includes at least one of the following:

second slice information and mapping indication.

Optionally, the method further comprises: the network device receives a second NAS message from the core network device. For example, the first core network device AMF receives an SMF second NAS message from the second core network device.

Optionally, the second NAS message includes the second slice information.

Optionally the second NAS message is a PDU session release order.

Optionally, the method further comprises:

the network device encapsulates the second slice information and the second NAS message to obtain a first NAS message.

Optionally, the method further comprises: the network device sends the first NAS message to the terminal device. For example, the first core network device sends the first NAS message to the terminal device through the access network device.

Optionally, the method further comprises:

the network device sends a registration accept message to the terminal device, wherein the registration accept message comprises at least one of the following components:

the first slice information is mapped to the second slice information;

the allowed slice information is the second slice information.

For example, the first core network device sends the above-mentioned registration acceptance message to the terminal device through the access network device.

Optionally, the first slice information and/or the second slice information is S-NSSAI.

Specific examples of the network device performing method 300 in this embodiment may be referred to the related descriptions of the network device such as AMF in the above method 200, and are not repeated herein for brevity.

Example one:

As shown in fig. 6, a session management method capable of maintaining service continuity may specifically include the following steps:

s10, the UE executes a Registration (Registration) flow to obtain an Allowed NSSAI. The UE establishes a PDU session (PDU session establishment for S-NSSAI 1) according to the S-NSSAI 1 corresponding to the service.

S11, when the UE leaves a cell supporting S-NSSAI 1 and the next cell does not support S-NSSAI 1, the RAN, such as a source base station and a target base station, firstly performs a switching flow, and PDU session (session) using S-NSSAI 1 cannot be switched.

During or after the handover, the original base station or the target base station may notify the AMF that the session has not been successfully handed over. Alternatively, the RAN may send an N2 MM message (mobility management message sent over the N2 interface) to the AMF, in which the PDU session ID may be carried. Optionally, the N2 MM message may also carry a mapping relationship between S-nsai 1 and S-nsai 2 (S-nsai 1mapped to S-nsai 2), or may carry S-nsai 2 and a mapping indication. Furthermore, if the AMF knows that S-NSSAI 1 maps to S-NSSAI 2, the mapping relationship of S-NSSAI 1 and S-NSSAI 2 (S-NSSAI 1mapped to S-NSSAI 2) may not be carried in the N2 MM message, or the S-NSSAI 2 and mapping indication may be carried.

After the UE moves to the new cell, if the RRC layer of the UE acquires a slice supported by the base station in the system information broadcast by the base station and then transmits the slice to the NAS layer of the UE, the NAS layer may learn that the base station does not support S-nsai 1. The UE may release the PDU session using S-nsai 1 locally.

After the handover is completed, the UE may initiate a registration procedure if it leaves a previously acquired Registration Area (RA). Alternatively, if the NAS layer knows that the base station does not support S-nsai 1, the registration request may not carry S-nsai 1. Since the registration request does not carry the S-nsai 1, after the amf receives the registration request, it determines that the S-nsai 1 is no longer requested by the UE, and may trigger the SMF to release the PDU session using the S-nsai 1.

S12, AMF informs SMF that PDU session of S-NSSAI 1 needs to be released, carrying PDU session Identifier (ID). Alternatively, the AMF may send an SM content release (context release) message to the SMF, where the message may carry the PDU session ID, a mapping relationship between S-nsai 1 and S-nsai 2, or a mapping indication and S-nsai 2. However, if the isolation of the network slice is considered, the above information may not be sent to the SMF.

S13, the SMF initiates a PDU session release, e.g. by N1N2 message transmission (N1N 2 msg transfer) sending the PDU session ID to the AMF. Alternatively, the SMF sends a NAS message to the AMF, which may be a PDU session release order (session release command). For example, the NAS message may be PDU session release command, which may include a session ID, a reactivation request (reactivation required), etc., and optionally, S-NSSAI 2. If the SMF does not know the mapping relationship between S-NSSAI 1 and S-NSSAI 2, S-NSSAI 2 may not be carried in this step.

S14 and S15, the AMF sends an N2 MM message to the RAN. For example, the AMF encapsulates the PDU session release command, session identification, and slice information requiring new PDU session in a NAS message, which is sent to the UE through the base station. The encapsulated NAS message may carry a session identifier. Optionally, the NAS message may also carry S-NSSAI 2. Optionally, the NAS message may also carry a PDU session release command. The PDU session release command may include a session ID, a reactivation request (reactivation required), and optionally S-NSSAI 2.

S16, the UE releases the old PDU session and establishes a new PDU session by using S-NSSAI 2.

Alternatively, the base station may be an original base station or a target base station.

Alternatively, the AMF may be changed in the above-described flow. For example, if the above flow includes 2 AMFs, the AMFs in S12 and S13 are source AMFs, and the source AMFs may forward the information received in S13 to the target AMFs, and the target AMFs may resume S14.

In this embodiment, the AMF may send slice information supported by the target base station to the UE through the RAN, so as to ensure service continuity, especially service continuity of SSC mode 2.

Example two:

as shown in fig. 7, a session management method capable of maintaining service continuity may specifically include the following steps:

S20, the RAN informs the mapping relation (S-NSSAI 1 mapped to S-NSSAI 2) of the AMF S-NSSAI 1 and the S-NSSAI2, for example, by the base station. For example, the base station transmits an N2 MM message to the AMF, where the message includes a mapping relationship between S-nsai 1 and S-nsai 2. The specific execution sequence of this step is not limited in this example, for example, before S23, the base station may notify the mapping relationship between AMF S-nsai 1 and S-nsai 2.

S21, the UE firstly executes a Registration (Registration) flow to obtain an Allowed NSSAI. The UE establishes a PDU session (PDU session establishment for S-NSSAI 1) according to the S-NSSAI 1 corresponding to the service.

S22, when the UE leaves a cell supporting S-NSSAI 1 and the next cell does not support S-NSSAI 1, the source base station and the target base station firstly execute a Handover (Handover) process, and a PDU session using S-NSSAI 1 cannot be handed over.

S23, after the handover is completed, the UE performs a Registration (Registration) procedure, and the UE sends a Registration request (Registration request) to the AMF, where the Requested slice information Requested nssai= { S-NSSAI 1}, which is optionally carried. If the RRC layer of the UE acquires the slice supported by the base station in the system information broadcast by the base station, the slice is transmitted to the NAS layer of the UE, and the NAS layer knows that the base station does not support S-NSSAI 1. The UE may not carry S-nsai 1 if the UE does not carry S-nsai, the UE may release the PDU session using S-nsai 1 locally.

Upon receipt of the registration request (Registration request), the AMF determines that there is a PDU session using S-nsai 1 and that S-nsai 1 maps to S-nsai 2.

S24, AMF informs SMF in S-NSSAI 1 to release the PDU session. For example, the AMF sends a Session release message to the SMF, where the Session release message includes a Session identifier (Session ID) that needs to be released.

S25, AMF maps S-nsai 1 to S-nsai 2 and puts allowed slice information allowed nsai= { S-nsai 2} in a registration accept (Registration accept) message to the UE.

S26, after receiving the mapping of the S-NSSAI 1 to the S-NSSAI 2, the UE establishes a PDU session by using the S-NSSAI 2. Alternatively, if the UE does not release the PDU session in S23, the old PDU session may be released at this step, initiating the establishment of the PDU session using S-nsai 2.

Alternatively, the AMF may change in the above procedure, if there are 2 AMFs, the AMFs in S23 and S25 are new AMFs, and the AMFs in S24 are old AMFs.

In this embodiment, the RAN may send the mapping relationship between S-nsai 1 and S-nsai 2 to the AMF. The AMF may send slice information supported by the target base station to the UE through the RAN, ensuring service continuity, especially SSC mode 2.

Fig. 8 is a schematic block diagram of a terminal device 400 according to an embodiment of the present application. The terminal device 400 may include:

a receiving unit 410, configured to receive second slice information supported by a second cell when the terminal device leaves a first cell supporting first slice information and enters the second cell not supporting the first slice information;

a releasing unit 420 for releasing the session using the first slice information;

and an establishing unit 430 for establishing a session using the second slice information.

Optionally, as shown in fig. 9, the terminal device further includes:

and the acquiring unit 440 is configured to acquire slice information supported by the access network device from a system message broadcasted by the access network device corresponding to the second cell when the terminal device moves to the second cell.

Optionally, the terminal device further includes:

a determining unit 450, configured to transmit slice information supported by the access network device to a NAS layer of a non-access stratum through a radio resource control RRC layer, so as to determine whether the first slice information is available (available) in the NAS layer.

Optionally, the releasing unit is further configured to locally release the PDU session using the first slice information, if it is determined that the first slice information is not available.

Optionally, the second slice information received by the terminal device is carried by a first NAS message, where the first NAS message is sent by the first core network device to the terminal device by the second slice information and a second NAS message from the second core network device.

Optionally, the second slice information is included in the second NAS message.

Optionally, the second NAS message is a PDU session release order.

Optionally, the second slice information received by the terminal device is carried through a registration acceptance message, where the registration acceptance message includes at least one of the following:

the first slice information is mapped to the second slice information;

the allowed slice information is the second slice information.

The terminal device 400 of the embodiment of the present application can implement the corresponding function of the terminal device in the foregoing method embodiment. The flow, function, implementation and beneficial effects corresponding to each module (sub-module, unit or assembly, etc.) in the terminal device 400 can be referred to the corresponding description in the above method embodiments, and will not be repeated here. It should be noted that, the functions described in the respective modules (sub-modules, units, or components, etc.) in the terminal device 400 of the application embodiment may be implemented by different modules (sub-modules, units, or components, etc.), or may be implemented by the same module (sub-module, unit, component, etc.).

Fig. 10 is a schematic block diagram of a network device 500 according to an embodiment of the present application. The network device 500 may include:

a sending unit 510, configured to send, to the terminal device, second slice information supported by a second cell when the terminal device leaves a first cell that supports first slice information and enters the second cell that does not support the first slice information.

Optionally, as shown in fig. 11, the network device further includes:

a first receiving unit 520, configured to receive a notification from the access network device, where the notification includes that the PDU session established using the first slice information in the handover procedure cannot be successfully handed over.

Optionally, the notification includes at least one of:

second slice information and mapping indication.

Optionally, the network device further comprises:

a second receiving unit 530, configured to receive a mapping relationship between the first slice information and the second slice information from the access network device.

Optionally, the network device further comprises:

the sending unit is further configured to send a session release message to the core network device, where the session release message includes an identifier of a PDU session that needs to be released, and the session release message is used to instruct the second core network device to release the PDU session that uses the first slice information.

Optionally, the session release message includes at least one of the following:

second slice information and mapping indication.

Optionally, the network device further comprises:

a third receiving unit 540, configured to receive the second NAS message from the core network device.

Optionally, the second NAS message includes the second slice information.

Optionally, the second NAS message is a PDU session release order.

Optionally, the network device further comprises:

and an encapsulation unit 550, configured to encapsulate the second slice information and the second NAS message to obtain a first NAS message.

Optionally, the sending unit is further configured to send the first NAS message to the terminal device.

Optionally, the sending unit is further configured to send a registration accept message to the terminal device, where the registration accept message includes at least one of:

the first slice information is mapped to the second slice information;

the allowed slice information is the second slice information.

Optionally, the network device is an AMF.

Optionally, the core network device is an SMF.

The network device 500 of the embodiment of the present application can implement the corresponding functions of the network device in the foregoing method embodiment. The flow, function, implementation and beneficial effects corresponding to each module (sub-module, unit or component, etc.) in the network device 500 can be referred to the corresponding description in the above method embodiments, which are not repeated here. It should be noted that, the functions described in the respective modules (sub-modules, units, or components, etc.) in the network device 500 of the application embodiment may be implemented by different modules (sub-modules, units, or components, etc.), or may be implemented by the same module (sub-module, unit, component, etc.).

Fig. 12 is a schematic structural diagram of a communication device 600 according to an embodiment of the present application. The communication device 600 comprises a processor 610, which processor 610 may call and run a computer program from a memory to cause the communication device 600 to implement the methods in embodiments of the present application.

Optionally, the communication device 600 may further comprise a memory 620. Wherein the processor 610 may invoke and run a computer program from the memory 620 to cause the communication device 600 to implement the method in the embodiments of the present application.

The memory 620 may be a separate device from the processor 610 or may be integrated into the processor 610.

Optionally, the communication device 600 may further include a transceiver 630, and the processor 610 may control the transceiver 630 to communicate with other devices, and in particular, may send information or data to other devices, or receive information or data sent by other devices.

The transceiver 630 may include a transmitter and a receiver, among others. Transceiver 630 may further include antennas, the number of which may be one or more.

Optionally, the communication device 600 may be a network device in the embodiment of the present application, and the communication device 600 may implement a corresponding flow implemented by the network device in each method in the embodiment of the present application, which is not described herein for brevity.

Optionally, the communication device 600 may be a terminal device in the embodiment of the present application, and the communication device 600 may implement a corresponding flow implemented by the terminal device in each method in the embodiment of the present application, which is not described herein for brevity.

Fig. 13 is a schematic structural diagram of a chip 700 according to an embodiment of the present application. The chip 700 includes a processor 710, and the processor 710 may call and run a computer program from a memory to implement the methods of the embodiments of the present application.

Optionally, chip 700 may also include memory 720. The processor 710 may invoke and run a computer program from the memory 720 to implement the method performed by the terminal device or the network device in the embodiments of the present application.

Wherein the memory 720 may be a separate device from the processor 710 or may be integrated into the processor 710.

Optionally, the chip 700 may also include an input interface 730. The processor 710 may control the input interface 730 to communicate with other devices or chips, and in particular, may obtain information or data sent by other devices or chips.

Optionally, the chip 700 may further include an output interface 740. The processor 710 may control the output interface 740 to communicate with other devices or chips, and in particular, may output information or data to other devices or chips.

Optionally, the chip may be applied to a network device in the embodiment of the present application, and the chip may implement a corresponding flow implemented by the network device in each method in the embodiment of the present application, which is not described herein for brevity.

Optionally, the chip may be applied to a terminal device in the embodiment of the present application, and the chip may implement a corresponding flow implemented by the terminal device in each method in the embodiment of the present application, which is not described herein for brevity.

The chips applied to the network device and the terminal device may be the same chip or different chips.

It should be understood that the chips referred to in the embodiments of the present application may also be referred to as system-on-chip chips, or the like.

The processors mentioned above may be general purpose processors, digital signal processors (digital signal processor, DSP), off-the-shelf programmable gate arrays (field programmable gate array, FPGA), application specific integrated circuits (application specific integrated circuit, ASIC) or other programmable logic devices, transistor logic devices, discrete hardware components, etc. The general-purpose processor mentioned above may be a microprocessor or any conventional processor.

The memory mentioned above may be volatile memory or nonvolatile memory, or may include both volatile and nonvolatile memory. The nonvolatile memory may be a read-only memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an electrically Erasable EPROM (EEPROM), or a flash memory. The volatile memory may be random access memory (random access memory, RAM).

It should be understood that the above memory is exemplary but not limiting, and for example, the memory in the embodiments of the present application may be Static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous Link DRAM (SLDRAM), direct RAM (DR RAM), and the like. That is, the memory in embodiments of the present application is intended to comprise, without being limited to, these and any other suitable types of memory.

Fig. 14 is a schematic block diagram of a communication system 800 according to an embodiment of the present application. The communication system 800 includes a terminal device 810 and a network device 820.

A terminal device 810 for receiving second slice information supported by a second cell when the terminal device leaves a first cell supporting first slice information and enters the second cell not supporting the first slice information; releasing the session using the first slice information; a session is established using the second slice information.

And the network device 820 is configured to send the second slice information supported by the second cell to the terminal device when the terminal device leaves the first cell supporting the first slice information and enters the second cell not supporting the first slice information.

Wherein the terminal device 810 may be adapted to implement the corresponding functions implemented by the terminal device in the above method, and the network device 820 may be adapted to implement the corresponding functions implemented by the network device, e.g. the first core network device AMF, in the above method. For brevity, the description is omitted here.

Optionally, the communication system may further comprise a second core network device, in particular see the corresponding functions implemented by the SMF in the above method. Optionally, the communication system may further comprise an access network device, e.g. a first access network device and/or a second access network device. In particular, reference may be made to corresponding functions implemented by the first access network device and/or the second access network device in the above method. For brevity, the description is omitted here.

In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions in accordance with embodiments of the present application are produced in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by a wired (e.g., coaxial cable, fiber optic, digital subscriber line (Digital Subscriber Line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that contains an integration of one or more available media. The usable medium may be a magnetic medium (e.g., a floppy Disk, hard Disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid State Disk (SSD)), or the like.

It should be understood that, in various embodiments of the present application, the sequence numbers of the foregoing processes do not mean the order of execution, and the order of execution of the processes should be determined by the functions and internal logic thereof, and should not constitute any limitation on the implementation process of the embodiments of the present application.

It will be clear to those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described systems, apparatuses and units may refer to corresponding procedures in the foregoing method embodiments, and are not repeated herein.

The foregoing is merely a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the present application, and the changes and substitutions should be covered in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

A session management method, comprising:

in the case that a terminal device leaves a first cell supporting first slice information and enters a second cell not supporting the first slice information, the terminal device receives second slice information supported by the second cell;

The terminal device releases a session using the first slicing information;

the terminal device establishes a session using the second slice information.
The method of claim 1, wherein the first slice information has a mapping relationship with the second slice information.
The method of claim 1, wherein the method further comprises:

and under the condition that the terminal equipment moves to the second cell, the terminal equipment acquires slice information supported by the access network equipment from a system message broadcast by the access network equipment corresponding to the second cell.
A method according to claim 3, wherein the method further comprises:

the Radio Resource Control (RRC) layer of the terminal device transmits slice information supported by the access network device to a non-access stratum (NAS) layer of the terminal device, so as to determine whether the first slice information is available (available) in the NAS layer.
The method of claim 4, wherein the terminal device releases a session using the first slice information, further comprising:

in case it is determined that the first slice information is not available, the terminal device locally releases a PDU session using the first slice information.
The method according to any of claims 1 to 5, wherein the second slice information received by the terminal device is carried by a first NAS message, the first NAS message being sent by a first core network device to the terminal device with the second slice information and a second NAS message from a second core network device.
The method of claim 6, wherein the second slice information is included in the second NAS message.
The method of claim 6 or 7, wherein the second NAS message is a PDU session release order.
The method according to any of claims 6 to 8, wherein the first core network device is an access and mobility management network element, AMF, and the second core network device is a session management network element, SMF.
The method according to any of claims 1 to 9, wherein the second slice information received by the terminal device is carried by a registration accept message comprising at least one of:

the first slice information is mapped to the second slice information;

the allowed slice information is the second slice information.
The method of any of claims 1 to 10, wherein the first slice information and/or second slice information is single network slice selection assistance information, S-NSSAI.
A session management method, comprising:

in the case that the terminal equipment leaves a first cell supporting first slice information and enters a second cell not supporting the first slice information, the network equipment sends second slice information supported by the second cell to the terminal equipment.
The method of claim 12, wherein the method further comprises:

the network device receives a notification from the access network device that the PDU session established using the first slice information in the handover procedure cannot be successfully handed over.
The method of claim 13, wherein the notification includes at least one of:

mapping relation between the first slice information and the second slice information;

second slice information and mapping indication.
The method of any of claims 12 to 14, wherein the method further comprises:

the network device receives a mapping relationship of the first slice information and the second slice information from the access network device.
The method of any of claims 12 to 15, wherein the method further comprises:

the network device sends a session release message to the core network device, wherein the session release message comprises an identifier of a PDU session to be released, and the session release message is used for indicating the core network device to release the PDU session using the first slice information.
The method of claim 16, wherein the session release message includes at least one of:

mapping relation between the first slice information and the second slice information;

second slice information and mapping indication.
The method according to claim 16 or 17, wherein the method further comprises:

the network device receives a second NAS message from the core network device.
The method of claim 18, wherein the second NAS message includes the second slice information.
The method of claim 18 or 19, wherein the second NAS message is a PDU session release order.
The method of any one of claims 18 to 20, wherein the method further comprises:

and the network equipment encapsulates the second slice information and the second NAS message to obtain a first NAS message.
The method of claim 21, wherein the method further comprises:

the network device sends the first NAS message to the terminal device.
The method of claim 22, wherein the method further comprises:

the network device sends a registration acceptance message to the terminal device, wherein the registration acceptance message comprises at least one of the following components:

The first slice information is mapped to the second slice information;

the allowed slice information is the second slice information.
The method of any of claims 12 to 23, wherein the network device is an AMF.
The method of any of claims 16 to 23, wherein the core network device is an SMF.
The method of any one of claims 12 to 25, wherein the first slice information and/or second slice information is S-nsai.
A terminal device, comprising:

a receiving unit, configured to receive second slice information supported by a second cell when a terminal device leaves a first cell supporting first slice information and enters the second cell not supporting the first slice information;

a releasing unit configured to release a session using the first slice information;

and the establishing unit is used for establishing a session by using the second slice information.
The terminal device of claim 27, wherein the first slice information has a mapping relationship with the second slice information.
The terminal device of claim 27, wherein the terminal device further comprises:

and the acquisition unit is used for acquiring slice information supported by the access network equipment from a system message broadcasted by the access network equipment corresponding to the second cell under the condition that the terminal equipment moves to the second cell.
The terminal device of claim 29, wherein the terminal device further comprises:

and the determining unit is used for transmitting the slice information supported by the access network equipment to a non-access stratum (NAS) layer through a Radio Resource Control (RRC) layer so as to determine whether the first slice information is available or not (available) in the NAS layer.
The terminal device of claim 30, wherein the releasing unit is further configured to locally release a PDU session using the first slice information if it is determined that the first slice information is not available.
The terminal device of any of claims 27 to 31, wherein the second slice information received by the terminal device is carried by a first NAS message, the first NAS message being sent to the terminal device by a first core network device with the second slice information and a second NAS message from a second core network device.
The terminal device of claim 32, wherein the second slice information is included in the second NAS message.
The terminal device of claim 32 or 33, wherein the second NAS message is a PDU session release order.
The terminal device of any of claims 32 to 34, wherein the first core network device is an access and mobility management network element, AMF, and the second core network device is a session management network element, SMF.
The terminal device of any of claims 27-35, wherein the second slice information received by the terminal device is carried by a registration accept message comprising at least one of:

the first slice information is mapped to the second slice information;

the allowed slice information is the second slice information.
The terminal device of any of claims 27-36, wherein the first slice information and/or second slice information is single network slice selection assistance information, S-NSSAI.
A network device, comprising:

a sending unit, configured to send second slice information supported by a second cell to a terminal device when the terminal device leaves a first cell supporting first slice information and enters the second cell not supporting the first slice information.
The network device of claim 38, wherein the network device further comprises:

and the first receiving unit is used for receiving a notification of the access network equipment, wherein the notification comprises that the PDU session established by using the first slice information in the switching flow cannot be successfully switched.
The network device of claim 39, wherein the notification includes at least one of:

Mapping relation between the first slice information and the second slice information;

second slice information and mapping indication.
The network device of any one of claims 38 to 40, wherein the network device further comprises:

and the second receiving unit is used for receiving the mapping relation between the first slice information and the second slice information from the access network equipment.
The network device of any one of claims 38 to 41, wherein the network device further comprises:

the sending unit is further configured to send a session release message to the core network device, where the session release message includes an identifier of a PDU session that needs to be released, and the session release message is used to instruct the second core network device to release the PDU session that uses the first slice information.
The network device of claim 42, wherein the session release message includes at least one of:

mapping relation between the first slice information and the second slice information;

second slice information and mapping indication.
The network device of claim 42 or 43, wherein the network device further comprises:

and the third receiving unit is used for receiving the second NAS message from the core network equipment.
The network device of claim 44, wherein the second NAS message includes the second slice information.
The network device of claim 44 or 45, wherein the second NAS message is a PDU session release order.
The network device of any of claims 44 to 46, wherein the network device further comprises:

and the encapsulation unit is used for encapsulating the second slice information and the second NAS message to obtain a first NAS message.
The network device of claim 47, wherein the sending unit is further configured to send the first NAS message to the terminal device.
The network device of claim 48, wherein the sending unit is further configured to send a registration accept message to the terminal device, where the registration accept message includes at least one of:

the first slice information is mapped to the second slice information;

the allowed slice information is the second slice information.
The network device of any one of claims 38 to 49, wherein the network device is an AMF.
The network device of any one of claims 42 to 49, wherein the core network device is an SMF.
The network device of any one of claims 38 to 51, wherein the first slice information and/or second slice information is S-nsai.
A terminal device, comprising: a processor and a memory for storing a computer program, the processor being adapted to invoke and run the computer program stored in the memory to cause the terminal device to perform the method according to any of claims 1 to 12.
A network device, comprising: a processor and a memory for storing a computer program, the processor for invoking and running the computer program stored in the memory to cause the network device to perform the method of any of claims 13 to 26.
A chip, comprising: a processor for calling and running a computer program from a memory, causing a device on which the chip is mounted to perform the method of any one of claims 1 to 12.
A chip, comprising: a processor for calling and running a computer program from a memory, causing a device on which the chip is mounted to perform the method of any of claims 13 to 26.
A computer readable storage medium storing a computer program which, when executed by a device, causes the device to perform the method of any one of claims 1 to 12.
A computer readable storage medium storing a computer program which, when executed by a device, causes the device to perform the method of any one of claims 13 to 26.
A computer program product comprising computer program instructions for causing a computer to perform the method of any one of claims 1 to 12.
A computer program product comprising computer program instructions for causing a computer to perform the method of any one of claims 13 to 26.
A computer program which causes a computer to perform the method of any one of claims 1 to 12.
A computer program which causes a computer to perform the method of any one of claims 13 to 26.