WO2022036508A1 - 一种发现目标amf的方法和装置 - Google Patents

一种发现目标amf的方法和装置 Download PDF

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Publication number
WO2022036508A1
WO2022036508A1 PCT/CN2020/109538 CN2020109538W WO2022036508A1 WO 2022036508 A1 WO2022036508 A1 WO 2022036508A1 CN 2020109538 W CN2020109538 W CN 2020109538W WO 2022036508 A1 WO2022036508 A1 WO 2022036508A1
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network
slice
source
target
identifier
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PCT/CN2020/109538
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English (en)
French (fr)
Inventor
姜志健
李章原
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华为技术有限公司
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Priority to CN202080062897.4A priority Critical patent/CN114391279B/zh
Priority to PCT/CN2020/109538 priority patent/WO2022036508A1/zh
Publication of WO2022036508A1 publication Critical patent/WO2022036508A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W48/00—Access restriction; Network selection; Access point selection
    • H04W48/02—Access restriction performed under specific conditions
    • H04W48/06—Access restriction performed under specific conditions based on traffic conditions

Definitions

  • the present application relates to the field of communication technologies, and in particular, to a method and apparatus for discovering a target access and mobility management function (Access and Mobility Management Function, AMF).
  • AMF Access and Mobility Management Function
  • the target AMF (Target AMF, T-AMF) in the target network after the switch and the source AMF (Source AMF, S-AMF) in the source network before the switch need to support both.
  • Cross-network handover includes handover between different operators' networks and handover between different subnets within the same operator's network.
  • the source network does not carry the slice information of the terminal device when discovering the target AMF, so the target AMF selected by the source AMF has a high probability of not being able to provide the original slice service for the terminal device, and the handover failure rate is high.
  • the source network can carry the slicing information of the terminal device in the source network when discovering the target AMF, but in fact, different subnets may have different network slicing plans, so In the process of cross-subnet handover, problems such as handover failure or misuse of network slices are often caused because the target network cannot identify the slice of the source network.
  • the embodiments of the present application provide a method and apparatus for discovering AMF, which are used to solve the problem of inaccurate discovery of target AMF by terminal equipment when switching access network equipment across networks.
  • a method for discovering AMF comprising: when a terminal device needs to switch from a source access network device in a first network to a target access network device in a second network, a first network device in the first network The network element obtains the target identifier of the first slice of the terminal device in the first network in the second network, and then the first network element determines the target AMF in the second network based on the target identifier, where the target AMF supports the first slice .
  • the first network element since the first network element determines the target AMF in the second network based on the target identifier of the first slice in the second network, the first network element can accurately hit the target network that supports all the first The AMF of the chip is used as the target AMF, so as to ensure that the subsequent handover process will not fail due to the wrong selection of the target AMF, and solve the problem that the target AMF is found to be inaccurate when the terminal device switches the access network device across the network. KPIs for network switching.
  • the first network element in the first network obtains the target identifier of the first slice in the second network, which may specifically include: the first network element selects a slice from the source network in the first network.
  • the NSSF sends a first request message, where the first request message includes the source identifier of the first slice in the first network; the first network element receives a first response message from the source NSSF, where the first response message includes the first slice Target identification in the second network, wherein the second network supports the first slice.
  • the first network element obtains the target identifier of the first slice in the second network through the source NSSF, and the method is simple and reliable.
  • the source NSSF stores the mapping relationship between the slice identifier of the first network and the slice identifier of the second network; or, the target NSSF in the second network stores the slice identifier of the first network and the slice identifier of the second network.
  • the mapping relationship between the slice identifiers of the two networks, the first response message is generated by the source NSSF according to the target identifier of the first slice in the second network queried from the target NSSF.
  • the source NSSF may determine the target identifier of the first slice in the second network for the first network element based on the mapping relationship stored by itself, or may initiate a request to the target NSSF to further obtain the first slice in the second network through the target NSSF.
  • the target identification in the second network improves the flexibility of the scheme.
  • the first network element in the first network obtains the target identifier of the first slice in the second network, which may specifically include: the first network element obtains the target identifier of the first slice in the first network according to the The mapping relationship between the source identifier, the slice identifier of the first network, and the slice identifier of the second network determines the target identifier of the first slice in the second network.
  • the first network element can directly determine the target identifier of the first slice in the second network based on the mapping relationship, and the method is simple and reliable.
  • the first network element stores the mapping relationship between the slice identifier of the first network and the slice identifier of the second network.
  • the first network element can directly determine the target identifier of the first slice in the second network based on the mapping relationship stored by itself, which can reduce the interaction process and make the method more efficient.
  • the first network element is a source AMF or a source network repository function NRF in the first network.
  • source AMF or the source NRF here is only an example and not a limitation, and the embodiments of the present application do not exclude the possibility of other implementation manners.
  • the method before the first network element in the first network acquires the target identifier of the first slice of the terminal device in the first network in the second network, the method further includes: the first network element determining The public land mobile network PLMN identity of the first network is different from the PLMN identity of the second network; or, the first network element determines that the PLMN identity of the first network and the PLMN identity of the second network are the same and the tracking area identity TAI and The TAI of the second network is different.
  • the first network element determines whether the terminal device is an Inter-PLMN handover (that is, the PLMN identity of the first network and the PLMN identity of the second network are different) or an intra-PLMN handover (that is, the PLMN identity of the first network and the PLMN identity of the second network are different).
  • the PLMN identifiers of the two networks are the same and the TAI of the first network and the TAI of the second network are different
  • the target identifier of the first slice in the second network is obtained, which further ensures the reliability of the solution.
  • a method for discovering a target AMF including: when a terminal device needs to switch from a source access network device in a first network to a target access network device in a second network, a second network element receives a request message, wherein the request message includes the source identifier of the first slice of the terminal device in the first network in the first network, and the second network element stores the information of the first network.
  • the mapping relationship between the slice identifier and the slice identifier of the second network determines the target of the first slice in the second network according to the source identifier and the mapping relationship identification; the second network element generates a response message according to the target identification, and the second network element sends the response message.
  • the second network element is a source network slice selection function NSSF in the first network; and the second network element receiving the request message includes: the source NSSF receives data from the first network The second network element generates a response message according to the target identifier, and the second network element sends the response message, including: the source NSSF generates a first response message according to the target identifier , the source NSSF sends the first response message to the first network element.
  • the first network element is a source AMF or a source network repository function NRF in the first network.
  • the second network element is a target NSSF in the second network; and the second network element receiving the request message includes: the target NSSF receives a request message from the first network.
  • a communication device is provided, the device is located in a first network, and may be, for example, a first network element or a chip provided inside the first network element, and the device includes a device for implementing the first aspect or the first aspect. Modules of the method described in any possible implementation manner.
  • the apparatus may include:
  • An acquiring unit configured to acquire the first access network device of the terminal device in the first network when the terminal device needs to switch from the source access network device in the first network to the target access network device in the second network target identifiers of all slices in the second network;
  • a determining unit configured to determine a target AMF in the second network based on the target identifier, wherein the target AMF supports the first slice.
  • the obtaining unit is specifically configured to: send a first request message to the source network slice selection function NSSF in the first network, where the first request message includes the first slice source identifier in the first network; receiving a first response message from the source NSSF, the first response message including the target identifier of the first slice in the second network, wherein, The second network supports the first slice.
  • the source NSSF stores a mapping relationship between the slice identifier of the first network and the slice identifier of the second network; or, the target NSSF in the second network stores The mapping relationship between the slice identifier of the first network and the slice identifier of the second network, the first response message is that the source NSSF is in the first slice according to the first slice queried from the target NSSF.
  • the target identifier in the second network is generated.
  • the obtaining unit is specifically used for:
  • the mapping relationship between the slice identifier of the first network and the slice identifier of the second network it is determined that the first slice is in the the target identifier in the second network.
  • the apparatus further includes a storage unit configured to store a mapping relationship between the slice identifier of the first network and the slice identifier of the second network.
  • the apparatus is a source AMF or a source network repository function NRF in the first network.
  • the determining unit is further configured to: before the acquiring unit acquires the target identifier of the first slice of the terminal device in the first network in the second network, determine The public land mobile network PLMN identity of the first network and the PLMN identity of the second network are different; or, it is determined that the PLMN identity of the first network and the PLMN identity of the second network are the same and the first network
  • the TAI of the tracking area is different from the TAI of the second network.
  • a communication device is provided, the device is located in a first network or a second network, and can be, for example, a second network element or a chip arranged inside the second network element, the device includes a device for performing the above-mentioned second aspect or a module of the method in any possible implementation manner of the second aspect.
  • the apparatus may include:
  • a receiving unit configured to receive a request message when the terminal device needs to switch from the source access network device in the first network to the target access network device in the second network, wherein the request message includes the the source identifier of the first slice of the terminal device in the first network in the first network, and the device stores the source identifier between the slice identifier of the first network and the slice identifier of the second network the mapping relationship;
  • a processing unit configured to determine the target identifier of the first slice in the second network according to the source identifier and the mapping relationship; and generate a response message according to the target identifier;
  • a sending unit configured to send the response message.
  • the apparatus is a source network slice selection function NSSF in the first network; the receiving unit is specifically configured to: receive a first request message from a first network element; the sending unit It is specifically used for: sending the first response message to the first network element.
  • the first network element is a source AMF or a source network repository function NRF in the first network.
  • the apparatus is a target NSSF in the second network; the receiving unit is specifically configured to: receive a second request message from a source NSSF in the first network; The unit is specifically configured to: send the second response message to the source NSSF.
  • a communication device comprising:
  • the at least one processor causes the apparatus to perform the first aspect or the first aspect through the communication interface by executing instructions stored in a memory
  • the at least one processor causes the apparatus to perform the first aspect or the first aspect through the communication interface by executing instructions stored in a memory
  • the memory is located outside the device.
  • the apparatus includes the memory connected to the at least one processor, the memory storing instructions executable by the at least one processor.
  • a communication device comprising:
  • the at least one processor causes the apparatus to perform the second aspect or the second aspect through the communication interface by executing instructions stored in a memory
  • the at least one processor causes the apparatus to perform the second aspect or the second aspect through the communication interface by executing instructions stored in a memory
  • the memory is located outside the device.
  • the apparatus includes the memory connected to the at least one processor, the memory storing instructions executable by the at least one processor.
  • a computer-readable storage medium comprising a program or an instruction, when the program or instruction is executed on a computer, the method described in the first aspect or any possible implementation manner of the first aspect is made be executed.
  • a computer-readable storage medium comprising a program or an instruction, when the program or instruction is run on a computer, the method described in the second aspect or any possible implementation manner of the second aspect is made be executed.
  • a ninth aspect provides a chip, which is coupled to a memory for reading and executing program instructions stored in the memory, so that the method described in the first aspect or any possible implementation of the first aspect be executed.
  • a tenth aspect provides a chip, which is coupled to a memory for reading and executing program instructions stored in the memory, so that the method described in the second aspect or any possible implementation manner of the second aspect be executed.
  • a computer program product comprising instructions, which, when run on a computer, cause the method described in the first aspect or any of the possible implementations of the first aspect to be performed.
  • a twelfth aspect provides a computer program product comprising instructions which, when run on a computer, cause the method described in the second aspect or any of the possible implementations of the second aspect to be performed.
  • Fig. 1 is the schematic diagram of the content of target information
  • 2A is a schematic diagram of Intra-AMF switching
  • 2B is a schematic diagram of Inter-AMF handover
  • FIG. 3 is a schematic diagram of a possible network slice deployment mode
  • Fig. 4 is the flow chart of Inter-PLMN handover
  • Fig. 5 is the flow chart of Intra-PLMN handover
  • FIG. 6 is a network architecture diagram of a possible communication system to which an embodiment of the application is applicable.
  • FIG. 7 is a flowchart of a method for discovering a target AMF provided by an embodiment of the present application.
  • Fig. 9 is the flow chart of the handover execution stage
  • FIG. 10 is a flowchart of a specific method for discovering a target AMF provided by an embodiment of the present application.
  • FIG. 11 is a flowchart of another specific method for discovering a target AMF provided by an embodiment of the present application.
  • FIG. 12 is a flowchart of another specific method for discovering a target AMF provided by an embodiment of the present application.
  • FIG. 13 is a schematic structural diagram of a communication device according to an embodiment of the present application.
  • FIG. 14 is a schematic structural diagram of another communication apparatus provided by an embodiment of the present application.
  • FIG. 15 is a schematic structural diagram of another communication apparatus provided by 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.
  • Handover is a basic concept in telecommunication networks, and it is a solution to ensure the service continuity of terminal equipment, that is, the source access network equipment (Source NG-RAN, S-NG-RAN) will pass the signal of the terminal equipment. Intensity and other measurement data sense the mobility of the terminal device.
  • the source access network device When the terminal device wants to leave the access network device and enter the coverage area of the adjacent access network device, the source access network device will select a target access network device for the terminal device. (Target NG-RAN, T-NG-RAN), at the same time inform the core network and target access network equipment to prepare resources and then notify the terminal equipment to access the target access network equipment.
  • the source access network device will send a handover request message to the AMF to send the handover target information (Target ID) to the AMF.
  • Target ID handover target information
  • Figure 1 is a schematic diagram of the content of the target information.
  • the target information includes information such as target access network device identification (such as RAN Node ID, eNB ID, RNC-ID), target tracking area identification (Tracking Area Identity, TAI) and other information, wherein the target
  • the access network device identification also includes the public land mobile network (Public Land Mobile Network, PLMN) identification of the target network.
  • PLMN Public Land Mobile Network
  • the AMF After the AMF receives the handover request message (Handover Required) from the source access network device, it checks whether the target access network device has an N2 connection with itself. If so, it defines the handover as an intra-AMF handover, as shown in Figure 2A As shown in Figure 2B, only the access network equipment needs to be switched without the AMF switching; otherwise, it is an inter-AMF (Inter-AMF) switching, as shown in Figure 2B, the access network equipment needs to be switched and the AMF needs to be switched.
  • Inter-AMF Inter-AMF
  • the source AMF needs to find the target AMF according to the handover target information provided by the source access network device, and then inform the target access network device through the target AMF to prepare resources in advance, and when everything is ready on the network side, the source connection The network access device then notifies the terminal device to switch to the target access network device.
  • Network Slice Network Slice in this paper also may be referred to simply as "slices"
  • 3GPP Third Generation Partnership Project
  • the so-called network slicing is simply understood as a virtual network. By allocating different resources to these virtual networks, it can meet the differentiated application requirements of telecommunications networks in all walks of life.
  • the network slice is identified by the Single Network Slice Selection Assistance Information (S-NSSAI), which can also be commonly known as the network slice identification.
  • S-NSSAI Single Network Slice Selection Assistance Information
  • the AMF in the network 1 supports slices 1 (hereinafter referred to as NS1) and NS2 (hereinafter referred to as NS2), and the AMF in the network 2 supports NS3 (hereinafter referred to as NS3).
  • NS1 slices 1
  • NS2 NS2
  • NS3 NS3
  • the source AMF needs to be able to find a target AMF that can satisfy the current slice used by the terminal device, and the handover can be successful.
  • the terminal device needs to move from the access network device of network 1 to the access network of network 2.
  • the end device is using NS1, but the source AMF selects a target AMF that only supports NS2 for it, then the handover will fail.
  • the source AMF needs to carry the network slice information being used by the terminal device when selecting the target AMF, so as to ensure that the target AMF can support at least one slice being used by the terminal device.
  • the handover scheme given by 3GPP is: the source AMF discovers the source AMF through the source network repository function (NF Repository Function, NRF) and the target NRF The target AMF finds that the request does not carry network slice information, so the target AMF selected by the source AMF has a high probability that it cannot provide the original slice service for the terminal device. If the target AMF initially selected by the source AMF cannot provide the original slice service for the terminal device, the source AMF can re-select the target AMF that can support the relevant network slice through AMF redirection (Reroute).
  • NRF source network repository function
  • Reroute AMF redirection
  • FIG. 4 is a flowchart of Inter-PLMN handover, including:
  • the source access network device sends a handover request to the source AMF, and the handover request includes the target information (Target ID) of the handover;
  • the source AMF determines that the target access network device has no N2 connection with itself according to the target information, and determines that the target AMF needs to be discovered through the NRF;
  • the source AMF sends a discovery request to the source NRF, and the discovery request includes query conditions, and the query conditions may include the identifier of the target PLMN (such as PLMN2), the target network function type (such as AMF), etc.;
  • the source NRF sends a discovery request to the target NRF, and the discovery request includes query conditions, and the query conditions may include the identifier of the target PLMN (such as PLMN2), the target network function type (such as AMF), etc.;
  • the target NRF determines that all the AMFs in the PLMN2 network meet the query conditions, and determines that all the information of the AMFs in the PLMN2 network is sent to the source NRF (for example, the list of AMFs supported by the PLMN2 network can be sent to the source NRF);
  • the target NRF sends a discovery response to the source NRF, and the discovery response includes the information of the AMF in the PLMN2 network (for example, includes the list of AMFs supported by the PLMN2 network);
  • the source NRF sends a discovery response to the source AMF, and the discovery response includes the information of the AMF in the PLMN2 network;
  • the source AMF selects an AMF from the AMFs in the discovery response according to factors such as priority, weight, load, etc., as the target AMF, such as target AMF1;
  • the source AMF sends a create UE context request (Namf_Communication_CreateUEContext Request) to the target AMF1; the target AMF1 receives the request from the source AMF;
  • the currently given handover scheme is: the source AMF discovers the target AMF through the source NRF and the target NRF, and the discovery request carries Network slice information.
  • the target network will not be able to identify the source during the cross-subnet handover process. The slicing of the network leads to the failure of switching or the misuse of network slicing.
  • FIG. 5 is a flowchart of Intra-PLMN handover, including:
  • the source access network device sends a handover request to the source AMF, and the handover request includes the target information (Target ID) of the handover;
  • the source AMF determines that the target access network device has no N2 connection with itself according to the target information, and determines that the target AMF needs to be discovered through the NRF;
  • the source AMF sends a discovery request to the source NRF, and the discovery request includes query conditions, which may include the identifiers of the slices (such as NS1 and NS2) used by the terminal device in the intranet 1, the target network function type (such as AMF), etc. ;
  • the source NRF sends a discovery request to the target NRF, and the discovery request includes query conditions, and the query conditions may include the identifiers of the slices (such as NS1 and NS2) used by the terminal device in the intranet 1, and the function type of the target network (such as AMF), etc. ;
  • the target NRF determines that all AMFs in the subnet 2 cannot provide the services of NS1 and NS2, and it is determined that the target AMF has failed to be discovered this time;
  • the identification of the same slice (or a slice with the same function) in the subnet 1 and the subnet 2 is different.
  • the slice identifier NS1 in subnet 1 is different from the slice identifier NS3 in subnet 2, but the slice identified by NS1 and the slice identified by NS3 are essentially the same slice.
  • the AMF in subnet 2 can provide Services for the slice identified by NS1.
  • Subnet 2 does not know the correspondence between the slice ID in Subnet 1 and the slice ID in Subnet 2.
  • Subnet 2 only judges Subnet 1 and Subnet 2 according to whether the same slice ID exists in Subnet 1 and Subnet 2. Whether the same slice is deployed in net2.
  • the target NRF searches whether there is NS1 or NS2 in the identifier of the slice supported by AMF in subnet 2, and finds that the identifier of the slice supported by AMF in this network is only NS3, and NS3 is different from NS1 and NS2, so determine the subnet In 2, the AMF can neither provide the service of the slice identified by NS1 nor the service of the slice identified by NS2, so it is determined that the target AMF has failed to be found this time.
  • the target NRF sends a discovery response to the source NRF, and the discovery response includes error information, which is used to indicate that the discovery of the target AMF failed this time;
  • the source NRF sends a discovery response to the source AMF, and the discovery response includes error information, which is used to indicate that the target AMF failed to be discovered this time;
  • the source AMF and the source access network device determine that the discovery of the target AMF fails, and the handover is terminated.
  • the terminal device could not switch to the subnet 2. But in fact, the AMF in the subnet 2 can provide the service of the slice identified by NS1, and the terminal device can switch to the subnet 2.
  • embodiments of the present application provide a method and apparatus for discovering a target AMF.
  • the source network first maps the source identifier of the slice used by the terminal device in the source network to the target identifier in the target network, and then finds the target in the target network based on the target identifier.
  • the AMF that supports the slice used by the terminal device in the target network can be accurately hit, so as to ensure that the subsequent handover process will not fail due to the wrong selection of the target AMF, thereby solving the problem that the terminal device discovers when switching access network devices across networks.
  • the problem of inaccurate target AMF can improve the key performance indicator (Key Performance Indicator, KPI) of network handover.
  • KPI Key Performance Indicator
  • the technical solutions of the embodiments of the present application can be applied to various communication systems, for example, the fourth generation (4th generation, 4G) communication system, the fifth generation (5th generation, 5G) communication system, the sixth generation (6th generation, 6G) communication system A communication system or other future evolution systems, or other various wireless communication systems using wireless access technology, etc., as long as the terminal equipment in the communication system needs to discover the target AMF, the technical solutions of the embodiments of the present application can be adopted.
  • FIG. 6 is a network architecture diagram of a possible communication system to which the embodiments of the present application are applied.
  • the communication system includes terminal equipment, source access network equipment, source NRF, source AMF, source network slice selection function (NSSF), target NSSF, target NRF, target access network equipment and target AMF.
  • the source access network device, the source NRF, the source AMF and the source NSSF are located in the first network, and the target NSSF, the target NRF, the target access network device and the target AMF are located in the second network.
  • the terminal device can move from the service area of the first network to the service area of the second network.
  • the terminal device can also move from the service range of the second network to the service range of the first network.
  • the terminal device moves from the service range of the first network to the service range of the second network as an example, that is, the terminal device moves from the source access network device to the target access network device .
  • the network elements in the first network and the network elements in the second network may be independently deployed, respectively, or may be deployed in a unified manner.
  • the network elements in the first network and the network elements in the second network are The respective operators are independently deployed, in other words, the first network and the second network element do not have a common network element.
  • the first network and the second network element may share network elements, or NEs may not be shared.
  • the source AMF in the first network and the target AMF in the second network element are two different AMFs
  • the source NRF in the first network and the target NRF in the second network element may be the same NRF
  • the first network The source NSSF and the target NSSF in the second network element may be the same NSSF or two different NSSFs.
  • AMF is the access and mobility management function network element of the core network in the 5G network, including the mobility management function of the mobility management entity (MME) in the network framework in the long term evolution (LTE), And joined the access management function.
  • MME mobility management entity
  • LTE long term evolution
  • AMF can be used to manage the access control and mobility of terminal equipment, for example, it can perform registration, connection, reachability, and mobility management of terminal equipment, and can provide session management message transmission channels for terminal equipment and SMF.
  • Authentication and authentication functions are provided when the terminal device is connected. It should be understood that AMF is only a name in the 5G network. In future communication systems, such as 6G, the access and mobility management function network elements of the core network can still be AMF, or have other names, which are not described in this application. limited.
  • the NSSF is a centralized management point for network slice information in the 5G core network, and supports determining the network slice instances that the UE is allowed to access according to the UE's slice selection assistance information and subscription information.
  • NRF a function that provides NF registration and NF discovery functions, NFs in different networks can discover each other and communicate through API interfaces.
  • An access network device including, for example, a base station (eg, an access point) may refer to a device in an access network that communicates with wireless terminals over an air interface through one or more sectors.
  • the base station may be used to convert received air frames to and from Internet Protocol (IP) packets and act as a router between the terminal and the rest of the access network, which may include the IP network.
  • IP Internet Protocol
  • the base station may also coordinate attribute management of the air interface.
  • the base station may include an evolved base station (eNB or e-NodeB, evolutional Node B) in an LTE system or an evolved LTE system (LTE-Advanced, LTE-A), or a small base station in an LTE system or an LTE-A system (micro/pico eNB), or it can also include the next generation node B (gNB) in the NR system, or a transmission point (TP), or a transmission and receiver point (transmission and receiver point, TRP), etc., the embodiments of the present application are not limited.
  • eNB or e-NodeB, evolutional Node B in an LTE system or an evolved LTE system (LTE-Advanced, LTE-A), or a small base station in an LTE system or an LTE-A system (micro/pico eNB)
  • gNB next generation node B
  • TP transmission point
  • TRP transmission and receiver point
  • a terminal device also referred to as a terminal, includes a device that provides voice and/or data connectivity to a user, and may include, for example, a handheld device with wireless connectivity, or a processing device connected to a wireless modem.
  • the terminal equipment may communicate with the core network via a radio access network (RAN), and exchange voice and/or data with the RAN.
  • RAN radio access network
  • the terminal equipment may include user equipment (UE), wireless terminal equipment, mobile terminal equipment, device-to-device (D2D) terminal equipment, V2X terminal equipment, machine-to-machine/machine-type communication ( machine-to-machine/machine-type communications, M2M/MTC) terminal equipment, Internet of things (IoT) terminal equipment, subscriber unit (subscriber unit), subscriber station (subscriber station), mobile station (mobile station) , remote station (remote station), access point (access point, AP), remote terminal (remote terminal), access terminal (access terminal), user terminal (user terminal), user agent (user agent), or user equipment (user device), etc.
  • IoT Internet of things
  • these may include mobile telephones (or "cellular" telephones), computers with mobile terminal equipment, portable, pocket-sized, hand-held, computer-embedded mobile devices, and the like.
  • mobile telephones or "cellular" telephones
  • PCS personal communication service
  • SIP session initiation protocol
  • WLL wireless local loop
  • PDA personal digital assistant
  • constrained devices such as devices with lower power consumption, or devices with limited storage capacity, or devices with limited computing power, etc.
  • it includes information sensing devices such as barcodes, radio frequency identification (RFID), sensors, global positioning system (GPS), and laser scanners.
  • RFID radio frequency identification
  • GPS global positioning system
  • the terminal device may also be a wearable device.
  • Wearable devices can also be called wearable smart devices or smart wearable devices, etc. It is a general term for the application of wearable technology to intelligently design daily wear and develop wearable devices, such as glasses, gloves, watches, clothing and shoes. Wait.
  • a wearable device is a portable device that is worn directly on the body or integrated into the user's clothing or accessories. Wearable device is not only a hardware device, but also realizes powerful functions through software support, data interaction, and cloud interaction.
  • wearable smart devices include full-featured, large-scale, complete or partial functions without relying on smart phones, such as smart watches or smart glasses, and only focus on a certain type of application function, which needs to cooperate with other devices such as smart phones.
  • Use such as all kinds of smart bracelets, smart helmets, smart jewelry, etc. for physical sign monitoring.
  • the various terminal devices described above if they are located on the vehicle (for example, placed in the vehicle or installed in the vehicle), can be considered as on-board terminal equipment.
  • the on-board terminal equipment is also called on-board unit (OBU). ).
  • the network function in FIG. 6 is only an example and not a limitation.
  • the first network or the second network may also include other network functions, such as unified data management (Unified Data Management, UDM).
  • UDM Unified Data Management
  • At least one of the following items refers to any combination of these items, including any combination of single item(s) or plural items(s), such as at least one of a, b or c (a), can mean: a, or b, or c, or a and b, or b and c, or a and c, or a and b and c.
  • the ordinal numbers such as “first” and “second” mentioned in the embodiments of the present application are used to distinguish multiple objects, and are not used to limit the order, sequence, priority or priority of multiple objects. Importance.
  • the first priority criterion and the second priority criterion are only for distinguishing different criteria, and do not indicate the difference in content, priority, or importance of the two criteria.
  • FIG. 7 it is a flowchart of a method for discovering a target AMF provided by an embodiment of the present application.
  • the method is applied to the communication system shown in FIG. 6 as an example.
  • the terminal device needs to switch from the source access network device in the first network to the target access network device in the second network
  • the first network element in the first network obtains the first network element of the terminal device in the first network.
  • Target identification of all slices in the second network
  • the terminal device moves from the coverage (or service range) of the source access network device to the coverage (or service range) of the target access network device, the terminal device needs to move from the The source access network device is handed over to the target access network device in the second network.
  • the ellipse-shaped dashed box around the source access network device represents the coverage of the source access network device
  • the ellipse-shaped dashed box around the target access network device represents the coverage of the target access network device.
  • the first network element determines that the handover is a cross-network handover, and then obtains the first network element in the first network. Target identification of all slices in the second network.
  • the manner in which the first network element determines that the handover is a cross-network handover scenario includes but is not limited to the following two:
  • the public land mobile network PLMN identifier of the first network is different from the PLMN identifier of the second network, and the first network element determines that the handover is a cross-network handover.
  • the handover is a handover between different operator networks.
  • Type 2 The first network element determines that the PLMN identity of the first network and the PLMN identity of the second network are the same and the tracking area identifier TAI of the first network is different from the TAI of the second network, then the first network element determines that the handover is a cross network switch. For example, the handover is a handover between different subnets within the same operator.
  • the second network element stores the mapping relationship between the slice identifier of the first network and the slice identifier of the second network.
  • the second network element may be the source AMF in the first network, or the source NRF in the first network, or the source NSSF in the first network, or the target NRF in the second network, or the target NSSF in the second network, etc. etc., which are not limited in the embodiments of the present application.
  • the mapping relationship between the slice identifier of the first network and the slice identifier of the second network includes but is not limited to the following: one slice identifier in the first network corresponds to multiple slice identifiers in the second network; or, One slice identifier in the second network corresponds to multiple slice identifiers in the first network; or, the slice identifiers of the first network are in one-to-one correspondence with the slice identifiers of the second network.
  • the embodiments of the present application do not specifically limit the mapping relationship. For ease of description, the following embodiments mainly take the mapping relationship as an example of one-to-one correspondence.
  • the first network element may be any network element in the first network, such as a source AMF or a source NRF, which is not limited in this embodiment of the present application.
  • the first network element may determine that the first slice is in the second network according to the mapping relationship between the slice identifier of the first network and the slice identifier of the second network, and the source identifier of the first slice in the first network.
  • the target identifier in the network; or, the second network element can determine the first network according to the mapping relationship between the slice identifier of the first network and the slice identifier of the second network, and the source identifier of the first slice in the first network.
  • Slice the target identifier in the second network and then send the determined target identifier to the first network element.
  • the first network element is the source AMF
  • the second network element is the same as the first network element, that is, the source AMF stores the mapping relationship between the slice identifier of the first network and the slice identifier of the second network.
  • the source AMF After receiving the handover request message from the source access network device, the source AMF determines the source identifier in the first network of the first slice used by the terminal device in the first network; The mapping relationship between the slice identifiers of the second network, the source identifier of the first slice in the first network, and the target identifier of the first slice in the second network are searched.
  • the first network element is the source AMF
  • the second network element is the source NSSF, that is, the source NSSF stores the mapping relationship between the slice identifier of the first network and the slice identifier of the second network.
  • the source AMF After receiving the handover request message from the source access network device, the source AMF determines the source identifier in the first network of the first slice used by the terminal device in the first network; the source AMF sends the first request message to the source NSSF, the first A request message contains the source identifier of the first slice in the first network; after receiving the first request message, the source NSSF, according to the mapping relationship between the slice identifier of the first network and the slice identifier of the second network, the first The source identifier of the slice in the first network is searched for the target identifier of the first slice in the second network, and a first response message is generated based on the target identifier of the first slice in the second network, and the first response message includes The target identifier of the first slice in the second network sends the first response message to the source AMF; the source AMF receives the first response message from the source NSSF, and obtains the first slice in the second network from the first response message. target ID in .
  • the source AMF determines the source identifier in the first network of the first slice used by the terminal device in the first network; the source AMF sends the first request message to the source NSSF , the first request message contains the source identifier of the first slice in the first network; after receiving the first request message, the source NSSF generates the source NSSF according to the mapping relationship between the slice identifier of the first network and the slice identifier of the second network a first response message, which includes the mapping relationship between the slice identifier of the first network and the slice identifier of the second network, and sends the first response message to the source AMF; the source AMF receives the first response from the source NSSF message, according to the mapping relationship between the slice identifier of the first network and the slice identifier of the second network, and the source identifier of the first slice in the first network, the target identifier of the first slice in the second network is searched.
  • the first network element is the source AMF
  • the second network element is the target NSSF, that is, the target NSSF stores the mapping relationship between the slice identifier of the first network and the slice identifier of the second network.
  • the source AMF After receiving the handover request message from the source access network device, the source AMF determines the source identifier in the first network of the first slice used by the terminal device in the first network; the source AMF sends the first request message to the source NSSF, the first A request message includes the source identifier of the first slice in the first network; after receiving the first request message, the source NSSF sends a second request message to the target NSSF, and the second request message includes the first slice in the first The source identifier in the network; after receiving the second request message, the target NSSF searches for the source identifier of the first slice in the first network according to the mapping relationship between the slice identifier of the first network and the slice identifier of the second network and the source identifier of the first slice in the first network.
  • the target identifier of the first slice in the second network generating a second response message based on the target identifier of the first slice in the second network, and the second response message includes the target identifier of the first slice in the second network , send the second response message to the source NSSF; after receiving the second response message, the source NSSF sends the first response message to the source AMF, and the first response message includes the target identifier of the first slice in the second network; the source The AMF receives the first response message from the source NSSF, and obtains the target identifier of the first slice in the second network from the first response message.
  • the source AMF determines the source identifier in the first network of the first slice used by the terminal device in the first network; the source AMF sends the first request message to the source NSSF , the first request message includes the source identifier of the first slice in the first network; after receiving the first request message, the source NSSF sends a second request message to the target NSSF, and the second request message includes the first slice in the first network.
  • the source identifier in the first network after receiving the second request message, the target NSSF generates a second response message according to the mapping relationship between the slice identifier of the first network and the slice identifier of the second network, and the second response message includes the first
  • the mapping relationship between the slice identifier of a network and the slice identifier of the second network sends a second response message to the source NSSF; after receiving the second response message, the source NSSF sends the first response message to the source AMF, and the first response
  • the message includes the mapping relationship between the slice identifier of the first network and the slice identifier of the second network; the source AMF receives the first response message from the source NSSF, according to the relationship between the slice identifier of the first network and the slice identifier of the second network
  • the mapping relationship of , the source identifier of the first slice in the first network, and the target identifier of the first slice in the second network is searched.
  • the source AMF determines the source identifier in the first network of the first slice used by the terminal device in the first network; the source AMF sends the first request message to the source NSSF , the first request message includes the source identifier of the first slice in the first network; after receiving the first request message, the source NSSF sends a second request message to the target NSSF, and the second request message includes the first slice in the first network.
  • the source identifier in the first network after receiving the second request message, the target NSSF generates a second response message according to the mapping relationship between the slice identifier of the first network and the slice identifier of the second network, and the second response message includes the first
  • the mapping relationship between the slice identifier of the first network and the slice identifier of the second network sends the second response message to the source NSSF; after receiving the second request message, the source NSSF will, according to the slice identifier of the first network and the slice identifier of the second network, send the second response message to the source NSSF.
  • a response message, the first response message includes the target identifier of the first slice in the second network, and sends the first response message to the source AMF; the source AMF receives the first response message from the source NSSF, receives the first response message from the first response message
  • the target identification of the first slice in the second network is obtained in .
  • the first network element is the source NRF
  • the second network element is the source NSSF, that is, the source NSSF stores the mapping relationship between the slice identifier of the first network and the slice identifier of the second network.
  • the source AMF After receiving the handover request message from the source access network device, the source AMF determines the source identifier in the first network of the first slice used by the terminal device in the first network, and sends a discovery request to the source NRF. Including the source identifier of the first slice in the first network; after receiving the discovery request from the source AMF, the source NRF sends a first request message to the source NSSF, and the first request message includes the first slice in the first network.
  • the source NSSF After receiving the first request message, the source NSSF searches for the first The target identifier of the slice in the second network, generating a first response message based on the target identifier of the first slice in the second network, the first response message including the target identifier of the first slice in the second network, and The first response message is sent to the source NRF; the source NRF receives the first response message from the source NSSF, and obtains the target identifier of the first slice in the second network from the first response message.
  • the source AMF determines the source identifier in the first network of the first slice used by the terminal device in the first network, and sends a discovery request to the source NRF.
  • the request includes the source identifier of the first slice in the first network; after receiving the discovery request from the source AMF, the source NRF sends a first request message to the source NSSF, and the first request message includes the first slice in the first The source identifier in the network; after receiving the first request message, the source NSSF generates a first response message according to the mapping relationship between the slice identifier of the first network and the slice identifier of the second network, and the first response message includes the first network The mapping relationship between the slice identifier of the first network and the slice identifier of the second network, the first response message is sent to the source NRF; the source NRF receives the first response message from the source NSSF, according to the slice identifier of the first network and the second network.
  • the first network element is the source NRF
  • the second network element is the target NSSF, that is, the target NSSF stores the mapping relationship between the slice identifier of the first network and the slice identifier of the second network.
  • the source AMF After receiving the handover request message from the source access network device, the source AMF determines the source identifier in the first network of the first slice used by the terminal device in the first network, and sends a discovery request to the source NRF. Contains the source identifier of the first slice in the first network; after receiving the discovery request from the source AMF, the source NRF sends the first request message to the source NSSF; after receiving the first request message, the source NSSF sends the first request message to the target NSSF.
  • the second request message contains the source identifier of the first slice in the first network; after receiving the second request message, the target NSSF will, according to the difference between the slice identifier of the first network and the slice identifier of the second network, The mapping relationship, the source identifier of the first slice in the first network, look up the target identifier of the first slice in the second network, generate a second response message based on the target identifier of the first slice in the second network, and the first
  • the second response message includes the target identifier of the first slice in the second network, and sends the second response message to the source NSSF; after receiving the second request message, the source NSSF sends the first response message to the source NRF, and the first response
  • the message includes the target identifier of the first slice in the second network; the source NRF receives the first response message from the source NSSF, and obtains the target identifier of the first slice in the second network from the first response message.
  • the source AMF determines the source identifier in the first network of the first slice used by the terminal device in the first network, and sends a discovery request to the source NRF.
  • the request includes the source identifier of the first slice in the first network; after receiving the discovery request from the source AMF, the source NRF sends a first request message to the source NSSF; after receiving the first request message, the source NSSF sends a message to the target NSSF Send a second request message, where the second request message includes the source identifier of the first slice in the first network; after receiving the second request message, the target NSSF will, according to the difference between the slice identifier of the first network and the slice identifier of the second network, The mapping relationship between the two generates a second response message, and the second response message includes the mapping relationship between the slice identifier of the first network and the slice identifier of the second network, and sends the second response message to the source NSSF; the source NSSF
  • the first response message After the second response message, send a first response message to the source NRF, the first response message includes the mapping relationship between the slice identifier of the first network and the slice identifier of the second network; the source NRF receives the first response message from the source NSSF , according to the mapping relationship between the slice identifier of the first network and the slice identifier of the second network, and the source identifier of the first slice in the first network, the target identifier of the first slice in the second network is searched.
  • the source AMF determines the source identifier in the first network of the first slice used by the terminal device in the first network, and sends a discovery request to the source NRF.
  • the request includes the source identifier of the first slice in the first network; after receiving the discovery request from the source AMF, the source NRF sends a first request message to the source NSSF; after receiving the first request message, the source NSSF sends a message to the target NSSF Send a second request message, where the second request message includes the source identifier of the first slice in the first network; after receiving the second request message, the target NSSF will, according to the difference between the slice identifier of the first network and the slice identifier of the second network, The mapping relationship between the two generates a second response message, and the second response message includes the mapping relationship between the slice identifier of the first network and the slice identifier of the second network, and sends the second response message to the source NSSF; the source NSSF
  • the second request message After the second request message, according to the mapping relationship between the slice identifier of the first network and the slice identifier of the second network, and the source identifier of the first slice in the first network, find the target of the first slice in the second network identifying, generating a first response message based on the target identifier of the first slice in the second network, the first response message including the target identifier of the first slice in the second network, and sending the first response message to the source NRF;
  • the source NRF receives the first response message from the source NSSF, and obtains the target identifier of the first slice in the second network from the first response message.
  • the slices used by the terminal device in the first network include the first slice and the second slice.
  • the source AMF can search for the corresponding target identifier for each of the multiple slices used by the terminal device in the first network, and the specific search method for each slice can refer to the above-mentioned search for the first slice in the second.
  • the way in which objects in the network are identified For example, the source AMF searches for the target identifier of the first slice in the second network based on the mapping relationship between the slice identifier of the first network and the slice identifier of the second network, and the source identifier of the first slice in the first network.
  • the source AMF searches for the target identifier of the second slice in the second network based on the mapping relationship between the slice identifier of the first network and the slice identifier of the second network, and the source identifier of the second slice in the first network.
  • each slice used by the terminal device in the first network does not necessarily have a target identifier in the second network.
  • the slices used by the terminal device in the first network include the first slice and the second slice, but the second network only deploys the first slice and does not deploy the second slice, so the source AMF or source NRF can only obtain the first slice.
  • Target identification of all slices in the second network For example, the slices used by the terminal device in the first network include the first slice, the second slice and the third slice, but the second network only deploys the first slice and the third slice without deploying the second slice, so the source AMF Or the source NRF can only obtain the target identifiers of the first slice and the third slice in the second network.
  • it does not rule out the possibility that each slice used in the first network does not have a target identifier in the second network that is, the second network does not deploy any slice used by the terminal device in the first network. case, the handover fails.
  • the second network deploys the first slice and the source AMF or the source NRF can obtain the target identifier of the first slice in the second network as an example.
  • the first network element determines a target AMF in the second network based on the target identifier, where the target AMF supports the first slice.
  • the first network element initiates a process of discovering the target AMF based on the target identifier of the first slice in the second network, so that the target NRF in the second network is Query the AMFs in the second network that can provide the first slicing service according to the target identifier of the first slicing in the second network, and return the queried information of the AMFs in the second network that can provide the first slicing service to the The first network element; the first network element selects an AMF as the target AMF from the AMFs that can provide the first slice service in the second network, and performs the process of the handover preparation stage, for example, notifying the target AMF to perform handover-related preparation activities, updating Access network device information of the terminal device, etc. After the process of the handover preparation stage is completed, the process of connecting the terminal device to the target access network device is performed.
  • the preparation process includes:
  • the S-AMF receives the handover request from the S-NG-RAN, determines that the terminal device needs to be handed over from the S-NG-RAN to the T-NG-RAN, and determines that this handover is a cross-network handover;
  • the S-AMF executes the process of discovering the target AMF
  • the S-AMF sends a create UE context request (Nsmf_Communication_CreateUEContext Request) to the T-AMF;
  • the T-AMF sends an update session management (Session Management, SM) context request (Nsmf_PDUSession_UpdateSMContext Request) to the SMF;
  • Session Management, SM Session Management
  • SMF selects the user plane function (User Plane Function, UPF) (UPF Selection);
  • S806A (optional) SMF sends an N4 Session Modification Request (N4 Session Modification Request) to the Protocol Data Unit Session Anchor (PDU Session Anchor, PSA) UPF;
  • N4 Session Modification Request N4 Session Modification Request
  • PDU Session Anchor PSA
  • UPF sends N4 Session Modification Response (N4 Session Modification Response) to SMF;
  • S806C (optional) SMF sends an N4 session establishment request (N4Session Establishment Request) to the target UPF (Target UPF, T-UPF);
  • T-UPF sends N4 Session Establishment Response to SMF;
  • the SMF sends an update SM context response (Nsmf_PDUSession_UpdateSMContext Response) to the T-AMF;
  • the T-AMF performs PDU Handover Response Supervision, that is, if the handover involves multiple PDU sessions, the T-AMF will wait for the update response messages of these PDU sessions respectively, and then continue to execute.
  • the T-AMF sends a handover request (Handover Request) to the T-NG-RAN;
  • the T-NG-RAN sends a handover request acknowledgement (Handover Request Acknowledge) to the T-AMF;
  • the T-AMF sends an update SM session context request (Nsmf_PDUSession_UpdateSMContext Request) to the SMF;
  • S811B (optional) SMF sends N4 Session Modification Request to T-UPF;
  • T-UPF sends N4 Session Modification Response to SMF;
  • SMF sends N4 session establishment request (N4Session Establishment Request) to source-UPF (Source UPF, S-UPF);
  • S811E (optional) S-UPF sends N4 Session Establishment Response to SMF;
  • the SMF sends an update SM session context response (Nsmf_PDUSession_UpdateSMContext Response) to the T-AMF;
  • the T-AMF sends a create UE context response (Nsmf_Communication_CreateUEContext Response) to the S-AMF.
  • FIG. 9 it is a flowchart of the switching execution stage, and the switching process includes:
  • the S-AMF sends a handover command (Handover Command) to the S-NG-RAN;
  • the S-NG-RAN sends a handover command (Handover Command) to the terminal device;
  • the source base station sends an uplink RAN status transfer (Uplink RAN Status Transfer) to the source AMF;
  • the source AMF forwards the RAN state transfer information (Namf_Communication_N1N2MessageTransfer) to the target AMF through the N1N2 message transfer interface;
  • the target AMF sends the downlink RAN Status Transfer (Downlink RAN Status Transfer) to the target base station;
  • S903A (optional) S-NG-RAN sends direct data forwarding to T-NG-RAN;
  • S903B (optional) S-NG-RAN sends indirect data forwarding to S-UPF;
  • the terminal device sends a handover confirmation (Handover Confirm) to the T-NG-RAN;
  • T-NG-RAN sends a handover notification (Handover Notify) to T-AMF;
  • the target AMF informs the source AMF that it has received the handover notification from the target base station_(Namf_Communication_N2InfoNotify);
  • the source AMF returns an acknowledgement message (Namf_Communication_N2InfoNotify ACK) to the target AMF;
  • the source AMF notifies the SMF to release the failed SM context_(Nsmf_PDUSession_ReleaseSMContext Request);
  • the target AMF sends an update SM context request (Nsmf_PDUSession_UpdateSMContext Request) to the SMF;
  • S908A (optional) SMF sends N4 session modification request (N4Session Modification Request)_ to the target UPF;
  • N4 session modification response N4Session Modification Response
  • S909A (optional) SMF sends an N4 Session Modification Request (N4 Session Modification Request) to the source UPF;
  • N4 session modification response N4Session Modification Response
  • S910A (optional) SMF sends an N4 session modification request (N4Session Modification Request) to the anchor UPF;
  • N4Session Modification Request N4Session Modification Request
  • the anchor UPF returns an N4 Session Modification Response to the SMF;
  • the SMF returns an update SM context response (Nsmf_PDUSession_UpdateSMContext Response) to the target AMF;
  • the replacement device in the device needs to trigger the registration update process after the switching process.
  • SMF sends N4 Session Release Request (N4 Session Release Request) to S-UPF;
  • S913B (optional) S-UPF sends N4 Session Release Response (N4 Session Release Response) to SMF;
  • S-AMF send user context release command (UE Context Release Command) to S-NG-RAN;
  • S-NG-RAN send user context release command to S-AMF to complete (UE Context Release Command Complete);
  • S915A (optional) SMF sends N4 Session Modification Request to T-UPF;
  • the T-UPF sends an N4 Session Modification Response (N4 Session Modification Response) to the SMF.
  • N4 Session Modification Response N4 Session Modification Response
  • the first network element in the first network first Obtain the target identifier of the first slice of the terminal device in the first network in the second network, and then determine the target AMF in the second network based on the target identifier, so that the target network that supports the first slice can be accurately hit.
  • AMF is used as the target AMF to ensure that the subsequent handover process will not fail due to the wrong selection of the target AMF, solve the problem that the target AMF is inaccurate when the terminal device switches the access network device across the network, and can improve the network handover of KPIs.
  • FIG. 10 it is a flowchart of a specific method for discovering a target AMF provided by an embodiment of the present application.
  • the mapping relationship between the slice identifier of the source network (the first network) and the slice identifier of the target network (the second network) is stored on the source NSSF, and the specific method for the source AMF to select the target AMF includes:
  • the source access network device initiates a handover process, and carries the handover target information (see FIG. 1 for the Target ID information element) to the source AMF.
  • the source AMF determines that it is an Inter-AMF handover according to the target information, and sends a request message to the source NSSF, where the request message includes the identifiers NS1 and NS2 of the slices used by the terminal device in the source network.
  • the source NSSF has the GetTargetNSSAI service, which can provide the requester with the mapping function of the network slice.
  • the request message sent by the source AMF to the source NSSF is used to call the GetTargetNSSAI service.
  • the request message provides information such as the Target ID information of the handover, the network slices (ie NS1 and NS2) used by the terminal device in the source network, and the original Serving PLMN of the terminal device (ie the PLMN of the source network).
  • the source NSSF uses the GetTargetNSSAI service to query the target identifiers of NS1 and NS2 in the target network, and returns a response message (including the network slice information NS3 mapped by NS1) to the source AMF.
  • the source NSSF performs the conversion according to the correspondence between the network slices agreed upon by the operators of the two networks; if the PLMNs of the source network and the target network are the same, the source NSSF switches the target
  • the Selected TAI in the ID information identifies whether to switch across networks and how to map network slices in different regions.
  • the source NSSF can maintain the network slice availability information of each AMF in the source network.
  • the structure of the network slice availability information is the list of TAIs supported under the AMF and the list of network slices supported under each TAI. Therefore, the source NSSF can check whether the Selected TAI in the handover Target ID information is included in the network slice availability list managed by itself, and can determine whether to switch across the network.
  • the target network slice is acquired according to the mapping relationship of slice identifiers between different networks stored locally by the source NSSF.
  • the source NSSF returns the mapped network slice information to the source AMF, which may be specifically returned in the form of a list.
  • NS1 of the source network corresponds to NS3 of the target network, but the services related to NS2 are not deployed in the target network. Therefore, the source NSSF cannot find the slice information corresponding to NS2, and only returns the mapped network slice corresponding to NS1 to AMF.
  • List NS3 without the corresponding list of mapped network slices for NS2.
  • the target network may carry indication information in the response message to indicate the reason why the source NSSF does not return the network slice information mapped by NS2 (that is, NS2 is not deployed in the target network); or, the response message does not carry the indication If the source AMF determines that there is no network slice information mapped by NS2 in the response message, it determines that NS2 is not deployed in the target network.
  • the source NSSF can return an empty mapped network slice list for the slice to the source AMF to save resources. overhead.
  • the request message sent by the source AMF to the source NSSF may reuse the GET interface (Nnssf_NSSelection) of the existing network slice selection of the source NSSF.
  • Slice info conversion request (slice-info-request-for-handover).
  • slice-info-request-for-handover may specifically include the following sub-cells:
  • target-id indicates the target information of the handover, which is composed of Target PLMN and Target TAI;
  • allowedNssaiCurrentAccess indicates a list of slices that can be used by the UE to be handed over in the source network, which needs to be mapped to the network slice identifier in the target network.
  • the response message returned by the source NSSF to the source AMF may reuse the existing network slice GET response of the source NSSF.
  • the query result may be returned through the network slice mapping (MappingOfSnssai) defined in 3GPP Technical Specification (TS) 29531.
  • the source AMF carries the target PLMN, the mapped network slice information (NS3), etc., and initiates a target AMF discovery process to the source NRF in the source network.
  • NS3 mapped network slice information
  • the source NRF addresses the target NRF in the target network according to the target PLMN, and sends a discovery request to the target NRF, where the discovery request carries the network slice information NS3.
  • the target NRF queries the AMFs in the target network that can provide the NS3 slicing service according to the network slicing information NS3 in the discovery request, the target NRF returns the list of AMFs that can provide the NS3 slicing service to the source NRF, and the source NRF then returns the AMF list to the source AMF.
  • the source AMF selects a target AMF from the AMF list according to factors such as priority, weight, load, etc., and performs the subsequent handover process.
  • factors such as priority, weight, load, etc.
  • the source NSSF in the source network maps the source identifier (NS1) in the source network of the slice used by the terminal device in the source network to the source identifier (NS1) in the target network.
  • the source AMF then performs the AMF discovery process based on the mapped slice identification (NS3), which can avoid the problem that the target network cannot identify the slice of the source network, resulting in handover failure or misuse of network slices, and improves network handover efficiency. KPIs.
  • FIG. 11 it is a flowchart of another specific method for discovering a target AMF provided by an embodiment of the present application.
  • the mapping relationship between the slice identifier of the source network (that is, the first network) and the slice identifier of the target network (that is, the second network) is stored on the target NSSF, and the specific method for the source AMF to select the target AMF includes:
  • the source access network device initiates a handover process, and carries the handover target information (see FIG. 1 for the Target ID information element) to the source AMF.
  • the source AMF determines that it is an Inter-AMF handover according to the target base station information, and sends a request message to the source NSSF, where the request message includes the identifiers NS1 and NS2 of the slices used by the terminal device in the source network.
  • the source NSSF sends a request message to the target NSSF, requesting to query the target identifiers of the slices (eg NS1 and NS2) used by the terminal device in the source network in the target network.
  • the request message contains the identifiers NS1 and NS2 of the slices used by the terminal device in the source network.
  • the target NSSF uses the GetTargetNSSAI service to query the target identifiers of NS1 and NS2 in the target network, and returns a response message (including the network slice information NS3 mapped by NS1) to the source NSSF.
  • the source NSSF returns a response message (including the network slice information NS3 mapped by NS1) to the source AMF.
  • the source AMF carries the target PLMN, the network slice information (NS3) mapped by the NS1, etc., and initiates a target AMF discovery process to the source NRF in the source network.
  • NS3 network slice information
  • the source NRF addresses the target NRF in the target network according to the target PLMN, and sends a discovery request to the target NRF, where the discovery request carries the network slice information NS3.
  • the target NRF queries the AMFs that can provide NS3 slicing services in the target network according to the network slicing information NS3 in the discovery request, returns the list of AMFs that can provide NS3 slicing services to the source NRF, and the source NRF returns the AMF list to the source AMF.
  • the source AMF selects a target AMF from the AMF list according to factors such as priority, weight, load, etc., and performs the subsequent handover process.
  • factors such as priority, weight, load, etc.
  • the target NSSF in the target network maps the source identifier (NS1) in the source network of the slice used by the terminal device in the source network to the source identifier (NS1) in the target network.
  • the source AMF performs the AMF discovery process based on the mapped slice identification (NS3), which can avoid the problem that the target network cannot identify the slice of the source network, which leads to the failure of the handover or the misuse of the network slice, and improves the network handover. of KPIs.
  • FIG. 12 it is a flowchart of another specific method for discovering a target AMF provided by an embodiment of the present application.
  • the mapping relationship between the slice identifier of the source network (that is, the first network) and the slice identifier of the target network (that is, the second network) is stored on the target NSSF, and the specific method for the source NRF to select the target AMF includes:
  • the source access network device initiates a handover process, and carries the handover target information (see FIG. 1 for the Target ID information element) to the source AMF.
  • the source AMF sends a discovery request to the source NRF, where the discovery request includes the identifiers NS1 and NS2 of slices used by the terminal device in the source network.
  • the source NRF sends a request message to the source NSSF, where the request message includes the identifiers NS1 and NS2 of the slices used by the terminal device in the source network.
  • the source NSSF sends a request message to the target NSSF, where the request message includes the identifiers NS1 and NS2 of the slices used by the terminal device in the source network.
  • the target NSSF uses the GetTargetNSSAI service to query the target identifiers of NS1 and NS2 in the target network, and returns a response message (including the network slice information NS3 mapped by NS1) to the source NSSF.
  • the source NSSF returns a response message (including the network slice information NS3 mapped by NS1) to the source NRF.
  • the source NRF After obtaining the network slice information NS3 mapped by NS1, the source NRF addresses the target NRF in the target network according to the target PLMN, and sends a discovery request to the target NRF, where the discovery request carries the network slice information NS3.
  • the target NRF queries the AMFs in the target network that can provide NS3 slicing services according to the network slicing information NS3 in the discovery request, the target NRF returns the list of AMFs that can provide NS3 slicing services to the source NRF, and the source NRF then returns the AMF list to the source AMF.
  • the source AMF selects a target AMF from the AMF list according to factors such as priority, weight, load, etc., and performs the subsequent handover process.
  • factors such as priority, weight, load, etc.
  • the target NSSF in the target network maps the source identifier (NS1) in the source network of the slice used by the terminal device in the source network to the source identifier (NS1) in the target network.
  • the source NRF performs the AMF discovery process based on the mapped slice identification (NS3), which can avoid the problem that the target network cannot identify the slice of the source network, which leads to handover failure or misuse of network slices, and improves network handover. of KPIs.
  • an embodiment of the present application provides a communication apparatus 1300, where the apparatus 1300 may be a first network element or a chip disposed inside the first network element (the first network element is, for example, a source AMF or a source NRF).
  • the apparatus 1300 has the function of implementing the first network element in the embodiments shown in FIGS. 7 to 12 above.
  • the apparatus 1300 includes the steps required to perform the steps performed by the first network element in the embodiments shown in the foregoing FIGS. 7 to 12 .
  • the functions or units or means may be implemented by software, or by hardware, or by executing corresponding software by hardware.
  • the apparatus 1300 may include:
  • the acquiring unit 1301 is configured to acquire, when the terminal device needs to switch from the source access network device in the first network to the target access network device in the second network, acquire the information of the terminal device in the first network. the target identifier of the first slice in the second network;
  • a determining unit 1302 configured to determine a target AMF in the second network based on the target identifier, where the target AMF supports the first slice.
  • the obtaining unit 1301 is specifically configured to:
  • the source NSSF receives a first response message from the source NSSF, where the first response message includes a target identifier of the first slice in the second network, wherein the second network supports the first piece.
  • the source NSSF stores a mapping relationship between the slice identifier of the first network and the slice identifier of the second network; or,
  • the target NSSF in the second network stores the mapping relationship between the slice identifier of the first network and the slice identifier of the second network, and the first response message is the source NSSF according to the data from the target NSSF.
  • the target identifier of the first slice in the second network that is queried by the NSSF is generated.
  • the obtaining unit 1301 is specifically configured to:
  • the mapping relationship between the slice identifier of the first network and the slice identifier of the second network it is determined that the first slice is in the the target identifier in the second network.
  • the apparatus further includes a storage unit configured to store a mapping relationship between the slice identifier of the first network and the slice identifier of the second network.
  • the apparatus is a source AMF or a source network repository function NRF in the first network.
  • the determining unit 1302 is further configured to:
  • the acquiring unit 1301 Before the acquiring unit 1301 acquires the target identifier of the first slice of the terminal device in the first network in the second network, determine the public land mobile network PLMN identifier of the first network and the The PLMN identifiers of the second network are different; or, it is determined that the PLMN identifier of the first network and the PLMN identifier of the second network are the same and the tracking area identifier TAI of the first network is different from the TAI of the second network.
  • an embodiment of the present application provides a communication apparatus 1400.
  • the apparatus 1400 may be a second network element or a chip disposed inside the second network element, for example, a source NSSF or a target NSSF.
  • the apparatus 1400 has the function of implementing the second network element in the embodiments shown in FIGS. 7 to 12.
  • the apparatus 1400 includes the steps required to perform the steps performed by the second network element in the embodiments shown in the above-mentioned FIGS. 7 to 12.
  • the functions or units or means may be implemented by software, or by hardware, or by executing corresponding software by hardware.
  • the apparatus 1400 may include:
  • the receiving unit 1401 is configured to receive a request message when the terminal device needs to switch from the source access network device in the first network to the target access network device in the second network, wherein the request message includes The source identifier of the first slice of the terminal device in the first network in the first network, and the device stores the slice identifier of the first network and the slice identifier of the second network.
  • a processing unit 1402 configured to determine the target identifier of the first slice in the second network according to the source identifier and the mapping relationship; and generate a response message according to the target identifier;
  • the sending unit 1403 is configured to send the response message.
  • the apparatus is a source network slice selection function NSSF in the first network
  • the receiving unit 1401 is specifically configured to: receive the first request message from the first network element;
  • the sending unit 1403 is specifically configured to: send the first response message to the first network element.
  • the first network element is a source AMF or a source network repository function NRF in the first network.
  • the device is a target NSSF in the second network
  • the receiving unit 1401 is specifically configured to: receive a second request message from a source NSSF in the first network;
  • the sending unit 1403 is specifically configured to: send the second response message to the source NSSF.
  • an embodiment of the present application further provides a communication apparatus 1500, including:
  • the memory 1502 is located outside the apparatus 1500 .
  • the apparatus 1500 includes the memory 1502, the memory 1502 is connected to the at least one processor 1501, and the memory 1502 stores instructions executable by the at least one processor 1501.
  • the memory 1502 is located outside the apparatus 1500 .
  • the apparatus 1500 includes the memory 1502, the memory 1502 is connected to the at least one processor 1501, and the memory 1502 stores instructions executable by the at least one processor 1501.
  • Figure 15 shows with dashed lines that memory 1502 is optional to apparatus 1500.
  • the processor 1501 and the memory 1502 may be coupled through an interface circuit, or may be integrated together, which is not limited here.
  • the specific connection medium between the processor 1501, the memory 1502, and the communication interface 1503 is not limited in the embodiments of the present application.
  • the processor 1501, the memory 1502, and the communication interface 1503 are connected through a bus 1504 in FIG. 15.
  • the bus is represented by a thick line in FIG. 15.
  • the connection between other components is only for schematic illustration. , is not limited.
  • the bus can be divided into an address bus, a data bus, a control bus, and the like. For ease of representation, only one thick line is shown in FIG. 15, but it does not mean that there is only one bus or one type of bus.
  • an embodiment of the present application further provides a communication apparatus 1600, including:
  • the at least one processor 1601 executes the instructions stored in the memory 1602 by executing the at least one processor 1602, so that the apparatus executes FIG. 7 through the communication interface 1603 - Method steps performed by the second network element in the embodiment shown in 12.
  • the memory 1602 is located outside the apparatus 1600 .
  • the apparatus 1600 includes the memory 1602, the memory 1602 is connected to the at least one processor 1601, and the memory 1602 stores instructions executable by the at least one processor 1601.
  • the memory 1602 is located outside the apparatus 1600 .
  • the apparatus 1600 includes the memory 1602, the memory 1602 is connected to the at least one processor 1601, and the memory 1602 stores instructions executable by the at least one processor 1601.
  • Figure 16 shows with dashed lines that memory 1602 is optional to apparatus 1600.
  • the processor 1601 and the memory 1602 may be coupled through an interface circuit, or may be integrated together, which is not limited here.
  • the specific connection medium between the processor 1601, the memory 1602, and the communication interface 1603 is not limited in the embodiments of the present application.
  • the processor 1601, the memory 1602, and the communication interface 1603 are connected through a bus 1604 in FIG. 16.
  • the bus is represented by a thick line in FIG. 16.
  • the connection between other components is only for schematic illustration. , is not limited.
  • the bus can be divided into an address bus, a data bus, a control bus, and the like. For ease of presentation, only one thick line is shown in FIG. 16, but it does not mean that there is only one bus or one type of bus.
  • the processor mentioned in the embodiments of the present application may be implemented by hardware or software.
  • the processor When implemented in hardware, the processor may be a logic circuit, an integrated circuit, or the like.
  • the processor When implemented in software, the processor may be a general-purpose processor implemented by reading software codes stored in memory.
  • the processor may be a central processing unit (Central Processing Unit, CPU), or other general-purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuit (Application Specific Integrated Circuit, ASIC) , Off-the-shelf Programmable Gate Array (Field Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.
  • a general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
  • the memory mentioned in the embodiments of the present application may be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory.
  • the non-volatile memory may be a read-only memory (Read-Only Memory, ROM), a programmable read-only memory (Programmable ROM, PROM), an erasable programmable read-only memory (Erasable PROM, EPROM), an electrically programmable read-only memory (Erasable PROM, EPROM). Erase programmable read-only memory (Electrically EPROM, EEPROM) or flash memory.
  • Volatile memory may be Random Access Memory (RAM), which acts as an external cache.
  • RAM Static RAM
  • DRAM Dynamic RAM
  • SDRAM Synchronous DRAM
  • SDRAM double data rate synchronous dynamic random access memory
  • Double Data Eate SDRAM DDR SDRAM
  • enhanced SDRAM ESDRAM
  • synchronous link dynamic random access memory Synchlink DRAM, SLDRAM
  • Direct Rambus RAM Direct Rambus RAM
  • the processor is a general-purpose processor, DSP, ASIC, FPGA or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components
  • the memory storage module
  • memory described herein is intended to include, but not be limited to, these and any other suitable types of memory.
  • an embodiment of the present application also provides a computer-readable storage medium, including a program or an instruction, when the program or instruction is run on a computer, the first network in the embodiment shown in FIG. 7-12 is made The method performed by the meta is executed.
  • an embodiment of the present application also provides a computer-readable storage medium, including a program or an instruction, when the program or instruction is run on a computer, the second network in the embodiment shown in FIGS. The method performed by the meta is executed.
  • an embodiment of the present application further provides a chip, which is coupled to a memory and used to read and execute program instructions stored in the memory, so that the first embodiment shown in FIGS. The method performed by the network element is performed.
  • an embodiment of the present application further provides a chip, which is coupled with a memory and used to read and execute program instructions stored in the memory, so that the second embodiment shown in FIG. 7-12 The method performed by the network element is performed.
  • the embodiments of the present application also provide a computer program product, including instructions, which, when executed on a computer, cause the method performed by the first network element in the embodiments shown in FIGS. 7-12 to be executed.
  • the embodiments of the present application further provide a computer program product, including instructions, which, when executed on a computer, cause the method performed by the second network element in the embodiment shown in FIGS. 7-12 to be executed.
  • the communication device 1300, the communication device 1400, the communication device 1500, and the communication device 1600 provided in the embodiments of the present application can be used to execute the methods provided by the corresponding embodiments in the embodiments shown in FIGS. 7-12, the obtained For technical effects, reference may be made to the foregoing method embodiments, which will not be repeated here.
  • 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

本申请公开了一种发现目标AMF的方法和装置，当终端设备需要从第一网络中的源接入网设备切换至第二网络中的目标接入网设备时，第一网络中的第一网元获取终端设备在第一网络中的第一切片在第二网络中的目标标识，进而第一网元基于目标标识确定第二网络中的目标AMF，其中目标AMF支持第一切片。由于第一网元是基于目标标识确定第二网络中的目标AMF，所以第一网元可以精确命中目标网络中支持第一切片的AMF，确保后续切换流程不会由于目标AMF的选择错误而引起的失败，解决终端设备在跨网络切换接入网设备时发现目标AMF不准确的问题，可以提升网络切换的KPI。

Description

一种发现目标AMF的方法和装置 技术领域
本申请涉及通信技术领域，尤其涉及一种发现目标接入和移动性管理功能(Access and Mobility Management Function，AMF)的方法和装置。
背景技术
终端设备在跨网络切换接入网络设备时，需要切换后的目标网络中的目标AMF(Target AMF，T-AMF)和切换前的源网络中的源AMF(Source AMF，S-AMF)同时支持终端设备的至少一个网络切片(Network Slice，NS)。
跨网络切换包括不同运营商网络间切换和同一运营商网络内部不同子网间切换两种。在不同运营商网络间切换场景中，源网络在发现目标AMF时不会携带终端设备的切片信息，所以源AMF选择的目标AMF很大概率不能为终端设备提供原切片服务，切换失败率高。在同一运营商网络内部不同子网间切换场景中，源网络在发现目标AMF时可以携带终端设备在源网中的切片信息，但是实际上不同子网之间可能有不同的网络切片规划，所以在跨子网的切换过程中，经常由于目标网络不能识别源网络的切片导致切换失败或者网络切片误用等问题。
现有技术中终端设备在跨网络切换接入网设备时，存在发现目标AMF不准确的问题。
发明内容
本申请实施例提供一种发现AMF的方法和装置，用于解决终端设备在跨网络切换接入网设备时发现目标AMF不准确的问题。
第一方面，提供一种发现AMF的方法，包括：当终端设备需要从第一网络中的源接入网设备切换至第二网络中的目标接入网设备时，第一网络中的第一网元获取终端设备在第一网络中的第一切片在第二网络中的目标标识，进而第一网元基于该目标标识确定第二网络中的目标AMF，其中目标AMF支持第一切片。
在本申请实施例中，由于第一网元是基于第一切片在第二网络中的目标标识确定第二网络中的目标AMF，所以第一网元可以精确命中目标网络中支持第一切片的AMF，将其作为目标AMF，进而确保后续切换流程不会由于目标AMF的选择错误而引起的失败，解决终端设备在跨网络切换接入网设备时发现目标AMF不准确的问题，可以提升网络切换的KPI。
一种可能的实施方式中，第一网络中的第一网元获取第一切片在第二网络中的目标标识，具体可以包括：第一网元向第一网络中的源网络切片选择功能NSSF发送第一请求消息，第一请求消息中包含第一切片在第一网络中的源标识；第一网元接收来自源NSSF的第一响应消息，第一响应消息中包括第一切片在第二网络中的目标标识，其中，第二网络支持第一切片。
该实施方式中，第一网元通过源NSSF获取到第一切片在第二网络中的目标标识，方法简单可靠。
一种可能的实施方式中，源NSSF储存有第一网络的切片标识与第二网络的切片标识 之间的映射关系；或者，第二网络中的目标NSSF储存有第一网络的切片标识与第二网络的切片标识之间的映射关系，第一响应消息是源NSSF根据从目标NSSF查询到的第一切片在第二网络中的目标标识生成的。
该实施方式中，源NSSF可以基于自身储存的映射关系为第一网元确定第一切片在第二网络中的目标标识，也可以向目标NSSF发起请求进一步通过目标NSSF获取第一切片在第二网络中的目标标识，提高了方案的灵活性。
一种可能的实施方式中，第一网络中的第一网元获取第一切片在第二网络中的目标标识，具体可以包括：第一网元根据第一切片在第一网络中的源标识、第一网络的切片标识与第二网络的切片标识之间的映射关系，确定第一切片在第二网络中的目标标识。
该实施方式中，第一网元可以基于映射关系直接确定第一切片在第二网络中的目标标识，方法简单可靠。
一种可能的实施方式中，第一网元储存第一网络的切片标识与第二网络的切片标识之间的映射关系。
该实施方式中，第一网元可以直接基于自身储存的映射关系确定第一切片在第二网络中的目标标识，可减少交互流程，方法更为高效。
一种可能的实施方式中，第一网元为第一网络中的源AMF或源网络存储库功能NRF。
应理解，这里的源AMF或源NRF仅为示例而非限定，本申请实施例不排除其他实现方式的可能性。
一种可能的实施方式中，在第一网络中的第一网元获取终端设备在第一网络中的第一切片在第二网络中的目标标识之前，方法还包括：第一网元确定第一网络的公共陆地移动网PLMN标识和第二网络的PLMN标识不同；或者，第一网元确定第一网络的PLMN标识和第二网络的PLMN标识相同且第一网络的跟踪区标识TAI和第二网络的TAI不同。
该实施方式中，第一网元在确定终端设备是Inter-PLMN切换(即第一网络的PLMN标识和第二网络的PLMN标识不同)或Intra-PLMN切换(即第一网络的PLMN标识和第二网络的PLMN标识相同且第一网络的TAI和第二网络的TAI不同)时，再获取第一切片在第二网络中的目标标识，进一步保证了方案的可靠性。
第二方面，提供一种发现目标AMF的方法，包括：当终端设备需要从第一网络中的源接入网设备切换至第二网络中的目标接入网设备时，第二网元接收请求消息，其中所述请求消息中包含所述终端设备在所述第一网络中的第一切片在所述第一网络中的源标识，所述第二网元储存有所述第一网络的切片标识与所述第二网络的切片标识之间的映射关系；所述第二网元根据所述源标识、所述映射关系，确定所述第一切片在所述第二网络中的目标标识；所述第二网元根据所述目标标识生成响应消息，所述第二网元发送所述响应消息。
一种可能的实施方式中，所述第二网元为所述第一网络中的源网络切片选择功能NSSF；所述第二网元接收请求消息，包括：所述源NSSF接收来自第一网元的第一请求消息；所述第二网元根据所述目标标识生成响应消息，所述第二网元发送所述响应消息，包括：所述源NSSF根据所述目标标识生成第一响应消息，所述源NSSF向所述第一网元发送所述第一响应消息。
一种可能的实施方式中，所述第一网元为所述第一网络中的源AMF或源网络存储库功能NRF。
一种可能的实施方式中，所述第二网元为所述第二网络中的目标NSSF；所述第二网元接收请求消息，包括：所述目标NSSF接收来自所述第一网络中的源NSSF的第二请求消息；所述第二网元根据所述目标标识生成响应消息，所述第二网元发送所述响应消息，包括：所述目标NSSF根据所述目标标识生成第二响应消息，所述目标NSSF向所述源NSSF发送所述第二响应消息。
第三方面，提供一种通信装置，所述装置位于第一网络，可以例如为第一网元或者设置在第一网元内部的芯片，该装置包括用于执行上述第一方面或第一方面任一种可能的实现方式所述方法的模块。
示例性的，该装置可以包括：
获取单元，用于当终端设备需要从所述第一网络中的源接入网设备切换至第二网络中的目标接入网设备时，获取所述终端设备在所述第一网络中的第一切片在所述第二网络中的目标标识；
确定单元，用于基于所述目标标识确定所述第二网络中的目标AMF，其中所述目标AMF支持所述第一切片。
一种可能的实施方式中，所述获取单元具体用于：向所述第一网络中的源网络切片选择功能NSSF发送第一请求消息，所述第一请求消息中包含所述第一切片在所述第一网络中的源标识；接收来自所述源NSSF的第一响应消息，所述第一响应消息中包括所述第一切片在所述第二网络中的目标标识，其中，所述第二网络支持所述第一切片。
一种可能的实施方式中，所述源NSSF储存有所述第一网络的切片标识与所述第二网络的切片标识之间的映射关系；或者，所述第二网络中的目标NSSF储存有所述第一网络的切片标识与所述第二网络的切片标识之间的映射关系，所述第一响应消息是所述源NSSF根据从所述目标NSSF查询到的所述第一切片在所述第二网络中的目标标识生成的。
一种可能的实施方式中，所述获取单元具体用于：
根据所述第一切片在所述第一网络中的源标识、所述第一网络的切片标识与所述第二网络的切片标识之间的映射关系，确定所述第一切片在所述第二网络中的目标标识。
一种可能的实施方式中，所述装置还包括储存单元，用于储存所述第一网络的切片标识与所述第二网络的切片标识之间的映射关系。
一种可能的实施方式中，所述装置为所述第一网络中的源AMF或源网络存储库功能NRF。
一种可能的实施方式中，所述确定单元还用于：在所获取单元获取所述终端设备在所述第一网络中的第一切片在所述第二网络中的目标标识之前，确定所述第一网络的公共陆地移动网PLMN标识和所述第二网络的PLMN标识不同；或者，确定所述第一网络的PLMN标识和所述第二网络的PLMN标识相同且所述第一网络的跟踪区标识TAI和所述第二网络的TAI不同。
第四方面，提供一种通信装置，所述装置位于第一网络或第二网络，可以例如为第二网元或者设置在第二网元内部的芯片，该装置包括用于执行上述第二方面或第二方面任一种可能的实现方式所述方法的模块。
示例性的，该装置可以包括：
接收单元，用于当终端设备需要从所述第一网络中的源接入网设备切换至所述第二网络中的目标接入网设备时，接收请求消息，其中所述请求消息中包含所述终端设备在所述 第一网络中的第一切片在所述第一网络中的源标识，所述装置储存有所述第一网络的切片标识与所述第二网络的切片标识之间的映射关系；
处理单元，用于根据所述源标识、所述映射关系，确定所述第一切片在所述第二网络中的目标标识；根据所述目标标识生成响应消息；
发送单元，用于发送所述响应消息。
一种可能的实施方式中，所述装置为所述第一网络中的源网络切片选择功能NSSF；所述接收单元具体用于：接收来自第一网元的第一请求消息；所述发送单元具体用于：向所述第一网元发送所述第一响应消息。
一种可能的实施方式中，所述第一网元为所述第一网络中的源AMF或源网络存储库功能NRF。
一种可能的实施方式中，所述装置为所述第二网络中的目标NSSF；所述接收单元具体用于：接收来自所述第一网络中的源NSSF的第二请求消息；所述发送单元具体用于：向所述源NSSF发送所述第二响应消息。
第五方面，提供一种通信装置，包括：
至少一个处理器；以及与所述至少一个处理器通信连接的通信接口；所述至少一个处理器通过执行存储器存储的指令，使得所述装置通过所述通信接口执行如第一方面或第一方面任一种可能的实现方式中所述方法。
可选的，所述存储器位于所述装置之外。
可选的，所述装置包括所述存储器，所述存储器与所述至少一个处理器相连，所述存储器存储有可被所述至少一个处理器执行的指令。
第六方面，提供一种通信装置，包括：
至少一个处理器；以及与所述至少一个处理器通信连接的通信接口；所述至少一个处理器通过执行存储器存储的指令，使得所述装置通过所述通信接口执行如第二方面或第二方面任一种可能的实现方式中所述方法。
可选的，所述存储器位于所述装置之外。
可选的，所述装置包括所述存储器，所述存储器与所述至少一个处理器相连，所述存储器存储有可被所述至少一个处理器执行的指令。
第七方面，提供一种计算机可读存储介质，包括程序或指令，当所述程序或指令在计算机上运行时，使得如第一方面或第一方面任一种可能的实现方式中所述方法被执行。
第八方面，提供一种计算机可读存储介质，包括程序或指令，当所述程序或指令在计算机上运行时，使得如第二方面或第二方面任一种可能的实现方式中所述方法被执行。
第九方面，提供一种芯片，所述芯片与存储器耦合，用于读取并执行所述存储器中存储的程序指令，使得第一方面或第一方面任一种可能的实现方式中所述方法被执行。
第十方面，提供一种芯片，所述芯片与存储器耦合，用于读取并执行所述存储器中存储的程序指令，使得第二方面或第二方面任一种可能的实现方式中所述方法被执行。
第十一方面，提供一种计算机程序产品，包括指令，当其在计算机上运行时，使得上述第一方面或第一方面任一种可能的实现方式中所述方法被执行。
第十二方面，提供一种计算机程序产品，包括指令，当其在计算机上运行时，使得上述第二方面或第二方面任一种可能的实现方式中所述方法被执行。
附图说明
图1为目标信息的内容的示意图；
图2A为Intra-AMF切换的示意图；
图2B为Inter-AMF切换的示意图；
图3为一种可能的网络切片部署方式的示意图；
图4为Inter-PLMN切换的流程图；
图5为Intra-PLMN切换的流程图；
图6为本申请实施例适用的一种可能的通信系统的网络架构图；
图7为本申请实施例提供的一种发现目标AMF的方法的流程图；
图8为切换准备阶段的流程图；
图9为切换执行阶段的流程图；
图10为本申请实施例提供的一种具体的发现目标AMF的方法的流程图；
图11为本申请实施例提供的另一种具体的发现目标AMF的方法的流程图；
图12为本申请实施例提供的另一种具体的发现目标AMF的方法的流程图；
图13为本申请实施例提供的一种通信装置的结构示意图；
图14为本申请实施例提供的另一种通信装置的结构示意图；
图15为本申请实施例提供的另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
切换(Handover)是电信网络中的一个基本概念，是一种保证终端设备业务连续性的方案，即：源接入网设备(Source NG-RAN，S-NG-RAN)会通过终端设备的信号强度等测量数据感知终端设备的移动性，当终端设备要离开本接入网设备进入相邻接入网设备的覆盖区域时，源接入网设备会为该终端设备选择一个目标接入网设备(Target NG-RAN，T-NG-RAN)，同时通知核心网和目标接入网设备准备资源完备后再通知终端设备接入到目标接入网设备。
在切换流程中，源接入网设备会向AMF发送切换请求消息，以将切换的目标信息(Target ID)发给AMF。图1为目标信息的内容的示意图，目标信息中包括目标接入网设备标识(如RAN Node ID、eNB ID、RNC-ID)、目标跟踪区标识(Tracking Area Identity，TAI)等信息，其中目标接入网设备标识中还包含了目标网络的公共陆地移动网(Public Land Mobile Network，PLMN)标识。
AMF从源接入网设备收到切换请求消息(Handover Required)后，检查目标接入网设备是否跟自身存在N2连接，如果存在即定义切换为AMF内(Intra-AMF)切换，如图2A所示，只需要切换接入网络设备而不需要切换AMF；否则为AMF间(Inter-AMF)切换，如图2B所示，需要切换接入网络设备且需要切换AMF。
在Inter-AMF的切换流程中，源AMF需要根据源接入网设备提供的切换目标信息找到目标AMF，再通过目标AMF通知目标接入网设备提前准备资源，等网络侧万事俱备，源接入网设备再通知终端设备切换到目标接入网设备。
上面介绍了切换的基本概念。在第五代移动通信技术(Fifth-Generation，5G)网络中， 第三代合作伙伴计划(3rd Generation Partnership Project，3GPP)协议引入了网络切片(Network Slice，NS)的概念(本文中网络切片还可简称为“切片”)。所谓网络切片，简单理解就是一张虚拟的网络，通过给这些虚拟网络分配不同的资源，能够满足各行各业对电信网络的差异化应用需求。网络切片通过单网络切片选择辅助信息(Single Network Slice Selection Assistance Information，S-NSSAI)进行标识，单网络切片选择辅助信息又可被俗称网络切片标识。
电信网络中各个网络功能(Network Function，NF)支持的网络切片存在差异性。例如，参见图3，网络1中的AMF支持切片1(下文简称NS1)、NS2(下文简称NS2)，网络2中的AMF支持NS3(下文简称NS3)。
在Inter-AMF的切换过程中，源AMF需要能够找到一个能满足终端设备当前使用切片的目标AMF，切换才能成功，比如终端设备需要从网络1的接入网设备移动到网络2的接入网络设备时，终端设备正在使用NS1，但是源AMF为其选择了一个仅支持NS2的目标AMF，那么切换就会失败。基于此，源AMF在选择目标AMF的时候需要携带终端设备正在使用的网络切片信息，以确保目标AMF至少能支持终端设备正在使用的一个切片。
但实际情况中，除了少数标准切片外，大部分网络切片都是各个运营商自己规划的，基于不同运营商的规划，相同切片在不同运营商网络中的标识可能不同，而不同切片在不同运营商网络中的标识也有可能相同。例如，中国移动规划了NS1作为医疗网络切片，但香港电讯盈科(PCCW)规划NS9作为医疗网络切片。并且，这种跨网络的场景除了不同运营商(即不同PLMN)之间的切换外，还包括同一运营商不同子网之间的切换，如中国移动的各省公司之间也存在网络切片的规划差异。这样会出现一个问题，在跨网络的切换过程中，源AMF基于本网的网络切片标识去其它网络发现目标网元的结果是不可信的。
针对跨网络切换终端设备的接入网设备的场景，目前存在以下两种切换方案：
第1种、在跨运营商网络切换(即PLMN间(Inter-PLMN)切换)时，3GPP给出的切换方案是：源AMF通过源网络存储库功能(NF Repository Function，NRF)、目标NRF发现目标AMF，发现请求中不携带网络切片信息，所以源AMF选择的目标AMF很大概率不能为终端设备提供原切片服务。如果源AMF初始选择的目标AMF不能为终端设备提供原切片服务，那么源AMF可以通过AMF重定向(Reroute)的方式重新选择能支持相关网络切片的目标AMF。但实际上，并非所有的AMF都支持AMF重定向功能，所以如果初选的AMF不能提供相应的网络切片服务且不支持AMF重定向功能，那么切换流程会失败。另外，对于支持AMF重定向功能的AMF，由于初选的AMF并非准确的AMF，源头存在缺陷(如发现参数不准确)，所以即便后续重选，也不一定能够选择准确的AMF。这增加了网络中的切换失败的概率，同时也增加了切换时延。
示例性的，参见图4，为Inter-PLMN切换的流程图，包括：
S401、源接入网设备给源AMF发送切换请求，切换请求中包含切换的目标信息(Target ID)；
S402、源AMF根据目标信息确定目标接入网设备与自身无N2连接，确定需要通过NRF发现目标AMF；
S403、源AMF向源NRF发送发现请求，发现请求中包含查询条件，该查询条件可以包括目标PLMN的标识(如PLMN2)、目标网络功能类型(如AMF)等；
S404、源NRF向目标NRF发送发现请求，发现请求中包含查询条件，该查询条件可以包括目标PLMN的标识(如PLMN2)、目标网络功能类型(如AMF)等；
S405、目标NRF确定PLMN2网络中的AMF都满足查询条件，确定将PLMN2网络中AMF的信息都发送给源NRF(例如可以向源NRF发送PLMN2网络所支持的AMF列表)；
S406、目标NRF向源NRF发送发现响应，发现响应中包含PLMN2网络中的AMF的信息(例如包含PLMN2网络所支持的AMF列表)；
S407、源NRF向源AMF发送发现响应，发现响应中包含PLMN2网络中的AMF的信息；
S408、源AMF根据优先级、权重、负荷等因素从发现响应中的AMF中选择一个AMF，作为目标AMF，例如目标AMF1；
S409、源AMF向目标AMF1发送创建UE上下文请求(Namf_Communication_CreateUEContext Request)；目标AMF1接收来自源AMF的请求；
S410、如果目标AMF1不支持本次协议数据单元(Protocol Data Unit，PDU)会话使用的切片，则本次PDU会话切换失败；一种极端的情况是：目标AMF1不支持终端正在使用的所有PDU会话的切片，那么整个切换流程失败。
第2种、对于在运营商内部子网切换(即PLMN内(Intra-PLMN)切换))场景，目前给出的切换方案是：源AMF通过源NRF、目标NRF发现目标AMF，发现请求中携带网络切片信息。但是，如果一个运营商内部按照覆盖区域等因素细分成了若干子网，并且不同的子网之间也有不同的网络切片规划，在跨子网的切换过程中也会由于目标网络不能识别源网络的切片导致切换失败或者网络切片误用的问题。
示例性的，参见图5，为Intra-PLMN切换的流程图，包括：
S501、源接入网设备给源AMF发送切换请求，切换请求中包含切换的目标信息(Target ID)；
S502、源AMF根据目标信息确定目标接入网设备与自身无N2连接，确定需要通过NRF发现目标AMF；
S503、源AMF向源NRF发送发现请求，发现请求中包含查询条件，该查询条件可以包括终端设备在内网1使用的切片的标识(如NS1、NS2)、目标网络功能类型(如AMF)等；
S504、源NRF向目标NRF发送发现请求，发现请求中包含查询条件，该查询条件可以包括终端设备在内网1使用的切片的标识(如NS1、NS2)、目标网络功能类型(如AMF)等；
S505、目标NRF确定子网2内所有AMF都不能提供NS1和NS2的服务，确定本次发现目标AMF失败；
由于子网1和子网2之间不同的网络切片规划，导致同一切片(或者说相同功能的切片)在子网1和子网2中的标识不同。例如，子网1中切片标识NS1和子网2中的切片标识NS3不同，但NS1所标识的切片和NS3所标识的切片实质是同一切片，换而言之，子网2内的AMF是可以提供NS1所标识的切片的服务。
但是，子网2并不知道子网1中的切片标识与子网2中的切片标识的对应关系，子网2仅根据子网1和子网2中是否存在相同的切片标识判断子网1和子网2中是否部署有相 同的切片。例如，目标NRF查找子网2中AMF所支持的切片的标识中是否有NS1或NS2，发现本网中AMF所支持的切片的标识只有NS3，而NS3与NS1、NS2均不同，故确定子网2内AMF既不能提供NS1所标识的切片的服务也不能提供NS2所标识的切片的服务，故确定本次发现目标AMF失败。
S506、目标NRF发送发现响应给源NRF，发现响应中包含错误信息，用于指示本次发现目标AMF失败；
S507、源NRF发送发现响应给源AMF，发现响应中包含错误信息，用于指示本次发现目标AMF失败；
S508、源AMF和源接入网设备确定发现目标AMF失败，切换终止。
由于S505目标NRF误判了子网2内的AMF不能提供NS1的服务，导致终端设备无法切换到子网2。但实际上，子网2内的AMF是可以提供NS1所标识的切片的服务的，终端设备是可以切换到子网2的。
通过上述图4和图5可以看出：终端设备在跨网络切换接入网设备时，存在发现目标AMF不准确的问题。
鉴于此，本申请实施例提供一种发现目标AMF的方法和装置。当终端设备需要跨网络切换接入网设备时，源网络先将终端设备在源网络中使用的切片的源标识映射为目标网络中的目标标识，然后再基于该目标标识去目标网络中发现目标AMF，这样可以精确命中目标网络中支持终端设备使用的切片的AMF，以确保后续切换流程不会由于目标AMF的选择错误而引起的失败，进而解决终端设备在跨网络切换接入网设备时发现目标AMF不准确的问题，可以提升网络切换的关键绩效指标(Key Performance Indicator，KPI)。具体方案将在后文进一步详细介绍。
本申请实施例的技术方案可以应用于各种通信系统，例如：第四代(4th generation，4G)通信系统、第五代(5th generation，5G)通信系统、第六代(6th generation，6G)通信系统或未来的其他演进系统、或其他各种采用无线接入技术的无线通信系统等，只要该通信系统中终端设备存发现目标AMF的需求，则均可以采用本申请实施例的技术方案。
例如，图6为本申请实施例适用的一种可能的通信系统的网络架构图。该通信系统中包括终端设备、源接入网设备、源NRF、源AMF、源网络切片选择功能(Network Slice Selection Function，NSSF)、目标NSSF、目标NRF、目标接入网设备以及目标AMF。其中源接入网设备、源NRF、源AMF以及源NSSF位于第一网络，目标NSSF、目标NRF、目标接入网设备以及目标AMF位于第二网络。终端设备可以从第一网络的服务范围移动到第二网络的服务范围。当然，在实际情况中终端设备也可以从第二网络的服务范围移动到第一网络的服务范围。为了便于表述，在接下来的实施例中，主要以终端设备从第一网络的服务范围移动到第二网络的服务范围为例，即终端设备从源接入网设备移动至目标接入网设备。
第一网络中的网元和第二网络中的网元可以分别独立部署，也可以统一部署。
例如，第一网络和第二网络分别是两个不同运营商的网络(即终端设备跨运营商网络切换接入网设备)，则第一网络中的网元和第二网络中的网元是各自运营商分别独立部署，换而言之，第一网络和第二网元没有共用的网元。
例如，第一网络和第二网络是同一运营商内部的不同子网(即终端设备在运营商内部子网切换接入网设备)，则第一网络和第二网元可以共用网元，也可以不共用网元。例如： 第一网络中的源AMF和第二网元中的目标AMF是两个不同的AMF，第一网络中的源NRF和第二网元中的目标NRF可以是同一NRF，第一网络中的源NSSF和第二网元中的目标NSSF可以是同一NSSF或者两个不同的NSSF。其中，AMF是5G网络中核心网的接入和移动性管理功能网元，包括了长期演进(long term evolution，LTE)中网络框架中移动管理实体(mobility management entity，MME)的移动性管理功能，并加入了接入管理功能。AMF可用于对终端设备的接入控制和移动性进行管理，例如可执行终端设备的注册、连接、可达性、移动性管理，可以为终端设备和SMF提供会话管理消息传输通道，还可以为终端设备接入时提供认证、鉴权功能等。应理解，AMF仅仅是5G网络中的名称，在未来的通信系统中，如6G中，核心网的接入和移动性管理功能网元仍可以是AMF，或有其它的名称，本申请不做限定。
NSSF是5G核心网中网络切片信息的集中管理点，支持根据UE的切片选择辅助信息、签约信息等确定UE允许接入的网络切片实例。
NRF，一个提供NF注册和NF发现功能的功能，不同网络中的NF可以相互发现并通过API接口进行通信。
接入网设备，例如包括基站(例如，接入点)，可以是指接入网中在空中接口上通过一个或多个扇区与无线终端通信的设备。基站可用于将收到的空中帧与网际协议(IP)分组进行相互转换，作为终端与接入网的其余部分之间的路由器，其中接入网的其余部分可包括IP网络。基站还可协调对空中接口的属性管理。例如，基站可以包括LTE系统或演进的LTE系统(LTE-Advanced，LTE-A)中的演进型基站(eNB或e-NodeB，evolutional Node B)，或LTE系统或LTE-A系统中的小基站(micro/pico eNB)，或者也可以包括NR系统中的下一代节点B(next generation node B，gNB)，或者是传输点(transmission point，TP)，也可以是收发节点(transmission and receiver point，TRP)等，本申请实施例并不限定。
终端设备，又可称为终端，包括向用户提供语音和/或数据连通性的设备，例如可以包括具有无线连接功能的手持式设备、或连接到无线调制解调器的处理设备。该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。该终端设备可以包括用户设备(user equipment，UE)、无线终端设备、移动终端设备、设备到设备通信(device-to-device，D2D)终端设备、V2X终端设备、机器到机器/机器类通信(machine-to-machine/machine-type communications，M2M/MTC)终端设备、物联网(internet of things，IoT)终端设备、订户单元(subscriber unit)、订户站(subscriber station)，移动站(mobile station)、远程站(remote station)、接入点(access point，AP)、远程终端(remote terminal)、接入终端(access terminal)、用户终端(user terminal)、用户代理(user agent)、或用户装备(user device)等。例如，可以包括移动电话(或称为“蜂窝”电话)，具有移动终端设备的计算机，便携式、袖珍式、手持式、计算机内置的移动装置等。例如，个人通信业务(personal communication service，PCS)电话、无绳电话、会话发起协议(session initiation protocol，SIP)话机、无线本地环路(wireless local loop，WLL)站、个人数字助理(personal digital assistant，PDA)、等设备。还包括受限设备，例如功耗较低的设备，或存储能力有限的设备，或计算能力有限的设备等。例如包括条码、射频识别(radio frequency identification，RFID)、传感器、全球定位系统(global positioning system，GPS)、激光扫描器等信息传感设备。
作为示例而非限定，在本申请实施例中，该终端设备还可以是可穿戴设备。可穿戴设 备也可以称为穿戴式智能设备或智能穿戴式设备等，是应用穿戴式技术对日常穿戴进行智能化设计、开发出可以穿戴的设备的总称，如眼镜、手套、手表、服饰及鞋等。可穿戴设备即直接穿在身上，或是整合到用户的衣服或配件的一种便携式设备。可穿戴设备不仅仅是一种硬件设备，更是通过软件支持以及数据交互、云端交互来实现强大的功能。广义穿戴式智能设备包括功能全、尺寸大、可不依赖智能手机实现完整或者部分的功能，例如：智能手表或智能眼镜等，以及只专注于某一类应用功能，需要和其它设备如智能手机配合使用，如各类进行体征监测的智能手环、智能头盔、智能首饰等。
而如上介绍的各种终端设备，如果位于车辆上(例如放置在车辆内或安装在车辆内)，都可以认为是车载终端设备，车载终端设备例如也称为车载单元(on-board unit，OBU)。
应理解，图6中的网络功能仅为示例而非限定，在实际情况中，第一网络或第二网络还可能包括其它网络功能，例如统一数据管理(Unified Data Management，UDM)等。
为了使本申请实施例的目的、技术方案和优点更加清楚，下面将结合附图对本申请实施例的技术方案作进一步地详细描述。
应理解，本申请实施例中的术语“系统”和“网络”可被互换使用。“至少一个”是指一个或者多个，“多个”是指两个或两个以上。“和/或”，描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B的情况，其中A,B可以是单数或者复数。字符“/”一般表示前后关联对象是一种“或”的关系。“以下至少一项(个)”或其类似表达，是指的这些项中的任意组合，包括单项(个)或复数项(个)的任意组合，例如a、b或c中的至少一项(个)，可以表示：a，或b，或c，或a和b，或b和c，或a和c，或a和b和c。
以及，除非有相反的说明，本申请实施例提及“第一”、“第二”等序数词是用于对多个对象进行区分，不用于限定多个对象的顺序、时序、优先级或者重要程度。例如，第一优先级准则和第二优先级准则，只是为了区分不同的准则，而并不是表示这两种准则的内容、优先级或者重要程度等的不同。
此外，本申请实施例和权利要求书及附图中的术语“包括”和“具有”不是排他的。例如，包括了一系列步骤或模块的过程、方法、系统、产品或设备，不限定于已列出的步骤或模块，还可以包括没有列出的步骤或模块。
如图7所示，为本申请实施例提供的一种发现目标AMF的方法的流程图。在下文的介绍过程中，以该方法应用于图6所示的通信系统为例。
S701、当终端设备需要从第一网络中的源接入网设备切换至第二网络中的目标接入网设备时，第一网络中的第一网元获取终端设备在第一网络中的第一切片在第二网络中的目标标识。
终端设备在移动的过程中，从源接入网设备的覆盖范围(或者说服务范围)移动到目标接入网设备的覆盖范围(或者说服务范围)时，终端设备需要从第一网络中的源接入网设备切换至第二网络中的目标接入网设备。如图6所示，源接入网设备外围的椭圆形的虚线框表征源接入网设备的覆盖范围，目标接入网设备外围的椭圆形的虚线框表征目标接入网设备的覆盖范围。
当终端设备需要从第一网络中的源接入网设备切换至第二网络中的目标接入网设备时，第一网元确定本次切换是跨网络切换，则获取第一网络中的第一切片在第二网络中的目标标识。
第一网元确定该切换是跨网络切换的场景的方式包括但不限于以下两种：
第1种、第一网络的公共陆地移动网PLMN标识和第二网络的PLMN标识不同，则第一网元确定该切换是跨网络切换。例如，该切换是在不同运营商网络间进行切换。
第2种、第一网元确定第一网络的PLMN标识和第二网络的PLMN标识相同且第一网络的跟踪区标识TAI和第二网络的TAI不同，则第一网元确定该切换是跨网络切换。例如，该切换是在同一运营商内部不同子网间进行切换。
在本申请实施例中，第二网元储存有第一网络的切片标识与第二网络的切片标识之间的映射关系。第二网元可以是第一网络中的源AMF，或者第一网络中的源NRF，或者第一网络中的源NSSF，或者第二网络中的目标NRF，或者第二网络中的目标NSSF等等，本申请实施例不做限定。
应理解，第一网络的切片标识与第二网络的切片标识之间的映射关系包括但不限于以下几种：第一网络中的一个切片标识对应第二网络中的多个切片标识；或者，第二网络中的一个切片标识对应第一网络中的多个切片标识；或者，第一网络的切片标识与第二网络的切片标识一一对应。本申请实施例对映射关系不做具体的限定，为了便于描述，在接下来的实施例中主要以映射关系是一一对应为例。
第一网元可以是第一网络中任一网元，例如源AMF或源NRF等，本申请实施例不做限定。相应的，第一网元可以根据第一网络的切片标识与第二网络的切片标识之间的映射关系，以及第一切片在第一网络中的源标识，确定第一切片在第二网络中的目标标识；或者，第二网元可以根据第一网络的切片标识与第二网络的切片标识之间的映射关系，以及第一切片在第一网络中的源标识，确定第一切片在第二网络中的目标标识，然后将确定出的目标标识发送给第一网元。
下面列举第一网元获取第一切片在第二网络中的目标标识的几种可能的具体实现方式。
方式1、第一网元是源AMF，第二网元和第一网元相同，即源AMF储存第一网络的切片标识与第二网络的切片标识之间的映射关系。
源AMF接收到来自源接入网设备切换请求消息后，确定终端设备在第一网络中使用的第一切片在第一网络中的源标识；然后，源AMF基于第一网络的切片标识与第二网络的切片标识之间的映射关系、第一切片在第一网络中的源标识，查找第一切片在第二网络中的目标标识。
方式2、第一网元是源AMF，第二网元是源NSSF，即源NSSF储存第一网络的切片标识与第二网络的切片标识之间的映射关系。
源AMF接收到来自源接入网设备切换请求消息后，确定终端设备在第一网络中使用的第一切片在第一网络中的源标识；源AMF向源NSSF发送第一请求消息，第一请求消息中包含第一切片在第一网络中的源标识；源NSSF收到第一请求消息后，根据第一网络的切片标识与第二网络的切片标识之间的映射关系、第一切片在第一网络中的源标识，查找第一切片在第二网络中的目标标识，基于第一切片在第二网络中的目标标识生成第一响应消息，第一响应消息中包括第一切片在第二网络中的目标标识，将第一响应消息发送给源AMF；源AMF接收来自源NSSF的第一响应消息，从第一响应消息中获得第一切片在第二网络中的目标标识。
或者，源AMF接收到来自源接入网设备切换请求消息后，确定终端设备在第一网络 中使用的第一切片在第一网络中的源标识；源AMF向源NSSF发送第一请求消息，第一请求消息中包含第一切片在第一网络中的源标识；源NSSF收到第一请求消息后，根据第一网络的切片标识与第二网络的切片标识之间的映射关系生成第一响应消息，第一响应消息中包括第一网络的切片标识与第二网络的切片标识之间的映射关系，将第一响应消息发送给源AMF；源AMF接收来自源NSSF的第一响应消息，根据第一网络的切片标识与第二网络的切片标识之间的映射关系、第一切片在第一网络中的源标识，查找第一切片在第二网络中的目标标识。
方式3、第一网元是源AMF，第二网元是目标NSSF，即目标NSSF储存第一网络的切片标识与第二网络的切片标识之间的映射关系。
源AMF接收到来自源接入网设备切换请求消息后，确定终端设备在第一网络中使用的第一切片在第一网络中的源标识；源AMF向源NSSF发送第一请求消息，第一请求消息中包含第一切片在第一网络中的源标识；源NSSF收到第一请求消息后，向目标NSSF发送第二请求消息，第二请求消息中包含第一切片在第一网络中的源标识；目标NSSF收到第二请求消息后，根据第一网络的切片标识与第二网络的切片标识之间的映射关系、第一切片在第一网络中的源标识，查找第一切片在第二网络中的目标标识，基于第一切片在第二网络中的目标标识生成第二响应消息，第二响应消息中包括第一切片在第二网络中的目标标识，将第二响应消息发送给源NSSF；源NSSF收到第二响应消息后，发送第一响应消息给源AMF，第一响应消息中包括第一切片在第二网络中的目标标识；源AMF接收来自源NSSF的第一响应消息，从第一响应消息中获得第一切片在第二网络中的目标标识。
或者，源AMF接收到来自源接入网设备切换请求消息后，确定终端设备在第一网络中使用的第一切片在第一网络中的源标识；源AMF向源NSSF发送第一请求消息，第一请求消息中包含第一切片在第一网络中的源标识；源NSSF收到第一请求消息后，向目标NSSF发送第二请求消息，第二请求消息中包含第一切片在第一网络中的源标识；目标NSSF收到第二请求消息后，根据第一网络的切片标识与第二网络的切片标识之间的映射关系生成第二响应消息，第二响应消息中包括第一网络的切片标识与第二网络的切片标识之间的映射关系，将第二响应消息发送给源NSSF；源NSSF收到第二响应消息后，发送第一响应消息给源AMF，第一响应消息中包括第一网络的切片标识与第二网络的切片标识之间的映射关系；源AMF接收来自源NSSF的第一响应消息，根据第一网络的切片标识与第二网络的切片标识之间的映射关系、第一切片在第一网络中的源标识，查找第一切片在第二网络中的目标标识。
或者，源AMF接收到来自源接入网设备切换请求消息后，确定终端设备在第一网络中使用的第一切片在第一网络中的源标识；源AMF向源NSSF发送第一请求消息，第一请求消息中包含第一切片在第一网络中的源标识；源NSSF收到第一请求消息后，向目标NSSF发送第二请求消息，第二请求消息中包含第一切片在第一网络中的源标识；目标NSSF收到第二请求消息后，根据第一网络的切片标识与第二网络的切片标识之间的映射关系生成第二响应消息，第二响应消息中包括第一网络的切片标识与第二网络的切片标识之间的映射关系，将第二响应消息发送给源NSSF；源NSSF收到第二请求消息后，根据第一网络的切片标识与第二网络的切片标识之间的映射关系、第一切片在第一网络中的源标识，查找第一切片在第二网络中的目标标识，基于第一切片在第二网络中的目标标识生成第一响应消息，第一响应消息中包括第一切片在第二网络中的目标标识，将第一响应消 息发送给源AMF；源AMF接收来自源NSSF的第一响应消息，从第一响应消息中获得第一切片在第二网络中的目标标识。
方式4、第一网元是源NRF，第二网元是源NSSF，即源NSSF储存第一网络的切片标识与第二网络的切片标识之间的映射关系。
源AMF接收到来自源接入网设备切换请求消息后，确定终端设备在第一网络中使用的第一切片在第一网络中的源标识，并向源NRF发送发现请求，该发现请求中包含第一切片在第一网络中的源标识；源NRF收到来自源AMF的发现请求后，发送第一请求消息给源NSSF，第一请求消息中包含第一切片在第一网络中的源标识；源NSSF收到第一请求消息后，根据第一网络的切片标识与第二网络的切片标识之间的映射关系、第一切片在第一网络中的源标识，查找第一切片在第二网络中的目标标识，基于第一切片在第二网络中的目标标识生成第一响应消息，第一响应消息中包括第一切片在第二网络中的目标标识，将第一响应消息发送给源NRF；源NRF接收来自源NSSF的第一响应消息，从第一响应消息中获得第一切片在第二网络中的目标标识。
或者，源AMF接收到来自源接入网设备切换请求消息后，确定终端设备在第一网络中使用的第一切片在第一网络中的源标识，并向源NRF发送发现请求，该发现请求中包含第一切片在第一网络中的源标识；源NRF收到来自源AMF的发现请求后，发送第一请求消息给源NSSF，第一请求消息中包含第一切片在第一网络中的源标识；源NSSF收到第一请求消息后，根据第一网络的切片标识与第二网络的切片标识之间的映射关系生成第一响应消息，第一响应消息中包括第一网络的切片标识与第二网络的切片标识之间的映射关系，将第一响应消息发送给源NRF；源NRF接收来自源NSSF的第一响应消息，根据第一网络的切片标识与第二网络的切片标识之间的映射关系、第一切片在第一网络中的源标识，查找第一切片在第二网络中的目标标识。
方式5、第一网元是源NRF，第二网元是目标NSSF，即目标NSSF储存第一网络的切片标识与第二网络的切片标识之间的映射关系。
源AMF接收到来自源接入网设备切换请求消息后，确定终端设备在第一网络中使用的第一切片在第一网络中的源标识，并向源NRF发送发现请求，该发现请求中包含第一切片在第一网络中的源标识；源NRF收到来自源AMF的发现请求后，发送第一请求消息给源NSSF；源NSSF收到第一请求消息后，向目标NSSF发送第二请求消息，第二请求消息中包含第一切片在第一网络中的源标识；目标NSSF收到第二请求消息后，根据第一网络的切片标识与第二网络的切片标识之间的映射关系、第一切片在第一网络中的源标识，查找第一切片在第二网络中的目标标识，基于第一切片在第二网络中的目标标识生成第二响应消息，第二响应消息中包括第一切片在第二网络中的目标标识，将第二响应消息发送给源NSSF；源NSSF收到第二请求消息后，发送第一响应消息给源NRF，第一响应消息中包括第一切片在第二网络中的目标标识；源NRF接收来自源NSSF的第一响应消息，从第一响应消息中获得第一切片在第二网络中的目标标识。
或者，源AMF接收到来自源接入网设备切换请求消息后，确定终端设备在第一网络中使用的第一切片在第一网络中的源标识，并向源NRF发送发现请求，该发现请求中包含第一切片在第一网络中的源标识；源NRF收到来自源AMF的发现请求后，发送第一请求消息给源NSSF；源NSSF收到第一请求消息后，向目标NSSF发送第二请求消息，第二请求消息中包含第一切片在第一网络中的源标识；目标NSSF收到第二请求消息后，根据第 一网络的切片标识与第二网络的切片标识之间的映射关系生成第二响应消息，第二响应消息中包括第一网络的切片标识与第二网络的切片标识之间的映射关系，将第二响应消息发送给源NSSF；源NSSF收到第二响应消息后，发送第一响应消息给源NRF，第一响应消息中包括第一网络的切片标识与第二网络的切片标识之间的映射关系；源NRF接收来自源NSSF的第一响应消息，根据第一网络的切片标识与第二网络的切片标识之间的映射关系、第一切片在第一网络中的源标识，查找第一切片在第二网络中的目标标识。
或者，源AMF接收到来自源接入网设备切换请求消息后，确定终端设备在第一网络中使用的第一切片在第一网络中的源标识，并向源NRF发送发现请求，该发现请求中包含第一切片在第一网络中的源标识；源NRF收到来自源AMF的发现请求后，发送第一请求消息给源NSSF；源NSSF收到第一请求消息后，向目标NSSF发送第二请求消息，第二请求消息中包含第一切片在第一网络中的源标识；目标NSSF收到第二请求消息后，根据第一网络的切片标识与第二网络的切片标识之间的映射关系生成第二响应消息，第二响应消息中包括第一网络的切片标识与第二网络的切片标识之间的映射关系，将第二响应消息发送给源NSSF；源NSSF收到第二请求消息后，根据第一网络的切片标识与第二网络的切片标识之间的映射关系、第一切片在第一网络中的源标识，查找第一切片在第二网络中的目标标识，基于第一切片在第二网络中的目标标识生成第一响应消息，第一响应消息中包括第一切片在第二网络中的目标标识，将第一响应消息发送给源NRF；源NRF接收来自源NSSF的第一响应消息，从第一响应消息中获得第一切片在第二网络中的目标标识。
应理解，以上五种方式仅为示例而非限定，在实际应用中不排除第一网元采用其他方式获取第一切片在第二网络中的目标标识的可能性。
需要说明的是，在本申请实施例中，终端设备在第一网络中使用的切片可以有多个。例如，终端设备在第一网络中使用的切片包括第一切片和第二切片。相应的，源AMF可以针对终端设备在第一网络中使用的多个切片中的每个切片分别查找对应的目标标识，针对每个切片的具体查找方式可以参考上述查找第一切片在第二网络中的目标标识的方式。例如：源AMF基于第一网络的切片标识与第二网络的切片标识之间的映射关系、第一切片在第一网络中的源标识，查找第一切片在第二网络中的目标标识；源AMF基于第一网络的切片标识与第二网络的切片标识之间的映射关系、第二切片在第一网络中的源标识，查找第二切片在第二网络中的目标标识。
进一步需要说明的是，终端设备在第一网络中使用的每个切片并不一定都在第二网络中存在目标标识。例如，终端设备在第一网络使用的切片包括第一切片和第二切片，但第二网络仅部署了第一切片未部署有第二切片，所以源AMF或源NRF只能获取到第一切片在第二网络中的目标标识。例如，终端设备在第一网络使用的切片包括第一切片、第二切片以及第三切片，但第二网络仅部署了第一切片和第三切片未部署有第二切片，所以源AMF或源NRF只能获取到第一切片和第三切片在第二网络中的目标标识。当然，不排除第一网络中使用的每个切片在第二网络中都不存在目标标识的可行性，即第二网络未部署有终端设备在第一网络中使用的任何一个切片，在这种情况下，切换失败。
在下文中，以第二网络部署了第一切片且源AMF或源NRF能够获取到第一切片在第二网络中的目标标识为例。
S702、第一网元基于目标标识确定第二网络中的目标AMF，其中目标AMF支持第一切片。
具体的，第一网元获得第一切片在第二网络中的目标标识后，基于第一切片在第二网络中的目标标识发起发现目标AMF的流程，使得第二网络中的目标NRF根据第一切片在第二网络中的目标标识查询第二网络中能提供第一切片服务的AMF，并将查询到的第二网络中能提供第一切片服务的AMF的信息返回给第一网元；第一网元从第二网络中能提供第一切片服务的AMF中选择一个AMF作为目标AMF，执行切换准备阶段的流程，例如通知目标AMF执行切换相关的准备活动，更新终端设备的接入网设备信息等。在切换准备阶段的流程完成后，再进行将终端设备接入到目标接入网设备的流程。
参见图8，为切换准备阶段的流程图，准备流程包括：
S801、S-AMF接收来自S-NG-RAN的切换请求，确定终端设备需要从S-NG-RAN切换至T-NG-RAN，且确定本次切换是跨网络切换；
S802、S-AMF执行发现目标AMF的流程；
S801-S802的具体实现过程可以参考上文S701-S702的具体实现过程，此处不再赘述。
S803、S-AMF向T-AMF发送创建UE上下文请求(Nsmf_Communication_CreateUEContext Request)；
S804、T-AMF向SMF发送更新会话管理(Session Management，SM)上下文请求(Nsmf_PDUSession_UpdateSMContext Request)；
S805、SMF选择用户面功能(User Plane Function，UPF)(UPF Selection)；
S806A、(可选)SMF向协议数据单元会话锚点(PDU Session Anchor，PSA)UPF发送N4会话修改请求(N4Session Modification Request)；
S806B、(可选)UPF向SMF发送N4会话修改响应(N4Session Modification Response)；
S806C、(可选)SMF向目标UPF(Target UPF，T-UPF)发送N4会话建立请求(N4Session Establishment Request)；
S806D、(可选)T-UPF向SMF发送N4会话建立响应(N4Session Establishment Response)；
S807、SMF向T-AMF发送更新SM上下文响应(Nsmf_PDUSession_UpdateSMContext Response)；
S808、T-AMF执行PDU切换响应监控(PDU Handover Response Supervision)，即如果切换涉及多个PDU会话，那么T-AMF会分别等待这些PDU会话的更新响应消息，随后再继续往下执行。
S809、T-AMF向T-NG-RAN发送切换请求(Handover Request)；
S810、T-NG-RAN向T-AMF发送切换请求确认(Handover Request Acknowledge)；
S811A、T-AMF向SMF发送更新SM会话上下文请求(Nsmf_PDUSession_UpdateSMContext Request)；
S811B、(可选)SMF向T-UPF发送N4会话修改请求(N4Session Modification Request)；
S811C、(可选)T-UPF向SMF发送N4会话修改响应(N4Session Modification Response)；
S811D、(可选)SMF向源-UPF(Source UPF，S-UPF)发送N4会话建立请求(N4Session Establishment Request)；
S811E、(可选)S-UPF向SMF发送N4会话建立响应(N4Session Establishment Response)；
S811F、SMF向T-AMF发送更新SM会话上下文响应 (Nsmf_PDUSession_UpdateSMContext Response)；
S812、T-AMF向S-AMF发送创建UE上下文响应(Nsmf_Communication_CreateUEContext Response)。
在S812之后，便开始正式的切换流程。
参见图9，为切换执行阶段的流程图，切换流程包括：
S901、S-AMF向S-NG-RAN发送切换命令(Handover Command)；
S902、S-NG-RAN向终端设备发送切换命令(Handover Command)；
S902A、(可选)源基站向源AMF发送上行的RAN状态传输(Uplink RAN Status Transfer)；
S902B、(可选)源AMF通过N1N2消息传输接口，向目标AMF转发RAN状态传输信息(Namf_Communication_N1N2MessageTransfer)；
S902C、(可选)目标AMF向目标基站发送下行的RAN状态传输(Downlink RAN Status Transfer)；
S903A、(可选)S-NG-RAN向T-NG-RAN发送直接数据转发(Derect data forwarding)；
S903B、(可选)S-NG-RAN向S-UPF发送间接数据转发(Inderect data forwarding)；
S904、终端设备向T-NG-RAN发送切换确认(Handover Confirm)；
S905、T-NG-RAN向T-AMF发送切换通知(Handover Notify)；
S906A、(可选)目标AMF向源AMF告知收到了目标基站的切换通知_(Namf_Communication_N2InfoNotify)；
S906B、(可选)源AMF向目标AMF返回应答消息(Namf_Communication_N2InfoNotify ACK)；
S906C、(可选)源AMF通知SMF释放切换失败的SM上下文_(Nsmf_PDUSession_ReleaseSMContext Request)；
S907、目标AMF向SMF发送更新SM上下文请求(Nsmf_PDUSession_UpdateSMContext Request)；
S908A、(可选)SMF向目标UPF发送N4会话修改请求(N4Session Modification Request)_；
S908B、(可选)目标UPF向SMF返回N4会话修改响应(N4Session Modification Response)；
S909A、(可选)SMF向源UPF发送N4会话修改请求(N4Session Modification Request)；
S909B、(可选)源UPF向SMF返回N4会话修改响应(N4Session Modification Response)；
S910A、(可选)SMF向锚点UPF发送N4会话修改请求(N4Session Modification Request)；
S910B、(可选)锚点UPF向SMF返回N4会话修改响应(N4Session Modification Response)；
S911、SMF向目标AMF返回更新SM上下文响应(Nsmf_PDUSession_UpdateSMContext Response)；
S912、注册程序(Registration Procedure)；
由于终端设备发生了跨AMF的移动，所以中的更换设备在切换流程后还需要触发注 册更新流程。
S913A、(可选)SMF向S-UPF发送N4会话释放请求(N4Session Release Request)；
S913B、(可选)S-UPF向SMF发送N4会话释放响应(N4Session Release Response)；
S914A、S-AMF向S-NG-RAN发送用户上下文释放命令(UE Context Release Command)；
S914B、S-NG-RAN向S-AMF发送用户上下文释放命令完成(UE Context Release Command Complete)；
S915A、(可选)SMF向T-UPF发送N4会话修改请求(N4Session Modification Request)；
S915B、(可选)T-UPF向SMF发送N4会话修改响应(N4Session Modification Response)。
通过上述可知，在本申请实施例中，当终端设备需要从第一网络中的源接入网设备切换至第二网络中的目标接入网设备时，第一网络中的第一网元先获取终端设备在第一网络中的第一切片在第二网络中的目标标识，然后再基于该目标标识确定第二网络中的目标AMF，这样可以精确命中目标网络中支持第一切片的AMF，将其作为目标AMF，进而确保后续切换流程不会由于目标AMF的选择错误而引起的失败，解决终端设备在跨网络切换接入网设备时发现目标AMF不准确的问题，可以提升网络切换的KPI。
应理解，本申请实施例中的各个实施方式可以相互结合以实现不同的技术效果。
为了便于更清楚地理解本申请实施例所提供的技术方案，下面列举几个更加详细的实施例。
实施例1
参见图10，为本申请实施例提供的一种具体的发现目标AMF的方法的流程图。源网络(第一网络)的切片标识与目标网络(第二网络)的切片标识的映射关系储存在源NSSF上，源AMF选择目标AMF的具体方法包括：
S1001、源接入网设备发起切换流程，携带切换的目标信息(Target ID信元参见图1)给源AMF。
S1002、源AMF根据目标信息判断是Inter-AMF切换，则向源NSSF发送请求消息，请求消息中包含终端设备在源网络中使用的切片的标识NS1和NS2。
源NSSF具有获取目标网络切片(GetTargetNSSAI)服务，可以为请求者提供网络切片的映射功能。这里源AMF向源NSSF发送的请求消息用于调用GetTargetNSSAI服务。请求消息中提供切换的Target ID信息、终端设备在源网络使用的网络切片(即NS1和NS2)，以及终端设备的原服务(Serving)PLMN(即源网络的PLMN)等信息。
S1003、源NSSF使用GetTargetNSSAI服务，查询NS1和NS2在目标网络中的目标标识，并返回响应消息(包含NS1映射后的网络切片信息NS3)给源AMF。
具体的，如果源网络与目标网络的PLMN不同，那么源NSSF根据两个网络的运营商约定的网络切片对应关系做转换；如果源网络与目标网络的PLMN相同，那么源NSSF再根据切换的Target ID信息中的Selected TAI识别是否跨网络切换、以及如何做不同区域的网络切片映射。
源NSSF可以维护源网络中各AMF的网络切片可用性信息，网络切片可用性信息的结构组成是AMF下支持的TAI列表，以及每个TAI下支持的网络切片列表。所以，源NSSF可以检查切换Target ID信息中的Selected TAI是否包含在自己管理的网络切片可用性列表中，就能判断是否跨网络切换。
当源NSSF识别终端设备跨网络切换时，根据源NSSF本地储存的不同网络间切片标识的映射关系获取目标网络切片。
源NSSF将映射后的网络切片信息返回给源AMF，具体可以是以列表的形式返回。图10中是以源网络的NS1对应目标网络的NS3，而NS2相关的业务在目标网络中没有部署为例，所以源NSSF无法找到NS2对应的切片信息，仅向AMF返回NS1对应的映射网络切片列表NS3，而没有NS2对应的映射网络切片列表。
可选的，目标网络可以在响应消息中携带指示信息，用以指示源NSSF没有返回NS2映射后的网络切片信息的原因(即目标网络中未部署NS2)；或者，响应消息中不携带该指示信息，源AMF判断响应消息中没有NS2映射后的网络切片信息则确定目标网络中未部署NS2。
另外，如果存在某个切片不需要映射，即该切片在目标网络和源网络中的标识相同，不需要做转换，则源NSSF可以针对该切片返回空映射网络切片列表给源AMF，以节省资源开销。
可选的，源AMF向源NSSF发送的请求消息，可以复用源NSSF已有的网络切片选择的GET接口(Nnssf_NSSelection)。
示例性的，可以在GET接口中增如下信元：
切片信息转换请求(slice-info-request-for-handover)。
进一步的，slice-info-request-for-handover具体可包含如下子信元：
1)、target-id：表示切换的目标信息，由Target PLMN和Target TAI组成；
2)、allowedNssaiCurrentAccess：表示待切换的UE在源网络中可使用的切片列表，需要映射到目标网络中的网络切片标识。
相应的，源NSSF向源AMF返回的响应消息，可以复用源NSSF已有的网络切片GET响应。例如，查询结果可以通过3GPP技术规范(Technical Specification，TS)29531中定义的网络切片映射(MappingOfSnssai)返回。
S1004、源AMF携带目标PLMN、映射后的网络切片信息(NS3)等向源网络中的源NRF发起目标AMF发现流程。
S1005、源NRF根据目标PLMN寻址到目标网络中的目标NRF，向目标NRF发送发现请求，发现请求中携带网络切片信息NS3。
S1006、目标NRF根据发现请求中的网络切片信息NS3，查询目标网络中能提供NS3切片服务的AMF，目标NRF将能提供NS3切片服务的AMF列表返回给源NRF，源NRF再将该AMF列表返回给源AMF。
之后，源AMF根据优先级、权重、负荷等因素从该AMF列表中选择一个目标AMF，进行后续的切换流程。后续切换流程可参考图8和图9所示的实施例，这里不再赘述。
本实施例中，当终端设备需要跨网络切换接入网设备时，源网络中的源NSSF将终端设备在源网络中使用的切片在源网络中的源标识(NS1)映射为目标网络中的目标标识(NS3)后，源AMF再基于映射后的切片标识(NS3)执行AMF发现流程，这样可以避免目标网络不能识别源网络的切片导致切换失败或者网络切片误用的问题，提升网络切换的KPI。
实施例2
参见图11，为本申请实施例提供的另一种具体的发现目标AMF的方法的流程图。源 网络(即第一网络)的切片标识与目标网络(即第二网络)的切片标识的映射关系储存在目标NSSF上，源AMF选择目标AMF的具体方法包括：
S1101、源接入网设备发起切换流程，携带切换的目标信息(Target ID信元参见图1)给源AMF。
S1102、源AMF根据目标基站信息判断是Inter-AMF切换，则向源NSSF发送请求消息，请求消息中包含终端设备在源网络中使用的切片的标识NS1和NS2。
S1103、源NSSF向目标NSSF发送请求消息，请求查询终端设备在源网络中使用的切片(如NS1和NS2)在目标网络中的目标标识。请求消息中包含终端设备在源网络中使用的切片的标识NS1和NS2。
S1104、目标NSSF使用GetTargetNSSAI服务，查询NS1和NS2在目标网络中的目标标识，并返回响应消息(包含NS1映射后的网络切片信息NS3)给源NSSF。
目标NSSF的GetTargetNSSAI服务的具体实现方式可以参考实施例1中源NSSF的GetTargetNSSAI服务的具体实现方式，这里不再赘述。
S1105、源NSSF返回响应消息(包含NS1映射后的网络切片信息NS3)给源AMF。
S1106、源AMF携带目标PLMN、NS1映射后的网络切片信息(NS3)等向源网络中的源NRF发起目标AMF发现流程。
S1107、源NRF根据目标PLMN寻址到目标网络中的目标NRF，向目标NRF发送发现请求，发现请求中携带网络切片信息NS3。
S1108、目标NRF根据发现请求中的网络切片信息NS3，查询目标网络中能提供NS3切片服务的AMF，将能提供NS3切片服务的AMF列表返回给源NRF，源NRF再将该AMF列表返回给源AMF。
之后，源AMF根据优先级、权重、负荷等因素从该AMF列表中选择一个目标AMF，进行后续的切换流程。后续切换流程可参考图8和图9所示的实施例，这里不再赘述。
本实施例中，当终端设备需要跨网络切换接入网设备时，目标网络中的目标NSSF将终端设备在源网络中使用的切片在源网络中的源标识(NS1)映射为目标网络中的目标标识(NS3)后，源AMF再基于该映射后的切片标识(NS3)执行AMF发现流程，这样可以避免目标网络不能识别源网络的切片导致切换失败或者网络切片误用的问题，提升网络切换的KPI。
实施例3
参见图12，为本申请实施例提供的另一种具体的发现目标AMF的方法的流程图。源网络(即第一网络)的切片标识与目标网络(即第二网络)的切片标识的映射关系储存在目标NSSF上，源NRF选择目标AMF的具体方法包括：
S1201、源接入网设备发起切换流程，携带切换的目标信息(Target ID信元参见图1)给源AMF。
S1202、源AMF向源NRF发送发现请求，发现请求中包含终端设备在源网络中使用的切片的标识NS1和NS2。
S1203、源NRF向源NSSF发送请求消息，请求消息中包含终端设备在源网络中使用的切片的标识NS1和NS2。
S1204、源NSSF向目标NSSF发送请求消息，请求消息中包含终端设备在源网络中使用的切片的标识NS1和NS2。
S1205、目标NSSF使用GetTargetNSSAI服务，查询NS1和NS2在目标网络中的目标标识，并返回响应消息(包含NS1映射后的网络切片信息NS3)给源NSSF。
这里目标NSSF的GetTargetNSSAI服务的具体实现方式可以参考实施例1中源NSSF的GetTargetNSSAI服务的具体实现方式，这里不再赘述。
S1206、源NSSF返回响应消息(包含NS1映射后的网络切片信息NS3)给源NRF。
S1207、源NRF获得NS1映射后的网络切片信息NS3后，根据目标PLMN寻址到目标网络中的目标NRF，向目标NRF发送发现请求，该发现请求中携带网络切片信息NS3。
S1208、目标NRF根据发现请求中的网络切片信息NS3，查询目标网络中能提供NS3切片服务的AMF，目标NRF将能提供NS3切片服务的AMF列表返回给源NRF，源NRF再将该AMF列表返回给源AMF。
之后，源AMF根据优先级、权重、负荷等因素从该AMF列表中选择一个目标AMF，进行后续的切换流程。后续切换流程可参考图8和图9所示的实施例，这里不再赘述。
本实施例中，当终端设备需要跨网络切换接入网设备时，目标网络中的目标NSSF将终端设备在源网络中使用的切片在源网络中的源标识(NS1)映射为目标网络中的目标标识(NS3)后，源NRF再基于该映射后的切片标识(NS3)执行AMF发现流程，这样可以避免目标网络不能识别源网络的切片导致切换失败或者网络切片误用的问题，提升网络切换的KPI。
以上结合附图7～12介绍了本申请实施例提供的方法，以下结合附图13～图16介绍本申请实施例提供的装置。
基于同一技术构思，本申请实施例提供一种通信装置1300，该装置1300可以为第一网元或者设置在第一网元内部的芯片(第一网元例如为源AMF或源NRF)。该装置1300具备实现上述附图7～12所示实施例中第一网元的功能，比如，该装置1300包括执行上述附图7～12所示实施例中第一网元所执行的步骤所对应的模块或单元或手段(means)，所述功能或单元或手段可以通过软件实现，或者通过硬件实现，也可以通过硬件执行相应的软件实现。
示例性的，参见图13，装置1300可以包括：
获取单元1301，用于当终端设备需要从所述第一网络中的源接入网设备切换至第二网络中的目标接入网设备时，获取所述终端设备在所述第一网络中的第一切片在所述第二网络中的目标标识；
确定单元1302，用于基于所述目标标识确定所述第二网络中的目标AMF，其中所述目标AMF支持所述第一切片。
一种可能的实施方式中，所述获取单元1301具体用于：
向所述第一网络中的源网络切片选择功能NSSF发送第一请求消息，所述第一请求消息中包含所述第一切片在所述第一网络中的源标识；
接收来自所述源NSSF的第一响应消息，所述第一响应消息中包括所述第一切片在所述第二网络中的目标标识，其中，所述第二网络支持所述第一切片。
一种可能的实施方式中，所述源NSSF储存有所述第一网络的切片标识与所述第二网络的切片标识之间的映射关系；或者，
所述第二网络中的目标NSSF储存有所述第一网络的切片标识与所述第二网络的切片标识之间的映射关系，所述第一响应消息是所述源NSSF根据从所述目标NSSF查询到的 所述第一切片在所述第二网络中的目标标识生成的。
一种可能的实施方式中，所述获取单元1301具体用于：
根据所述第一切片在所述第一网络中的源标识、所述第一网络的切片标识与所述第二网络的切片标识之间的映射关系，确定所述第一切片在所述第二网络中的目标标识。
一种可能的实施方式中，所述装置还包括储存单元，用于储存所述第一网络的切片标识与所述第二网络的切片标识之间的映射关系。
一种可能的实施方式中，所述装置为所述第一网络中的源AMF或源网络存储库功能NRF。
一种可能的实施方式中，所述确定单元1302还用于：
在所获取单元1301获取所述终端设备在所述第一网络中的第一切片在所述第二网络中的目标标识之前，确定所述第一网络的公共陆地移动网PLMN标识和所述第二网络的PLMN标识不同；或者，确定所述第一网络的PLMN标识和所述第二网络的PLMN标识相同且所述第一网络的跟踪区标识TAI和所述第二网络的TAI不同。
上述方法实施例涉及的各步骤的所有相关内容均可以援引到对应功能模块的功能描述，在此不再赘述。
基于同一技术构思，本申请实施例提供一种通信装置1400，该装置1400可以为第二网元或者设置在第二网元内部的芯片，第二网元例如为源NSSF或目标NSSF。该装置1400具备实现上述附图7～12所示实施例中第二网元的功能，比如，该装置1400包括执行上述附图7～12所示实施例中第二网元所执行的步骤所对应的模块或单元或手段(means)，所述功能或单元或手段可以通过软件实现，或者通过硬件实现，也可以通过硬件执行相应的软件实现。
示例性的，参见图14，装置1400可以包括：
接收单元1401，用于当终端设备需要从所述第一网络中的源接入网设备切换至所述第二网络中的目标接入网设备时，接收请求消息，其中所述请求消息中包含所述终端设备在所述第一网络中的第一切片在所述第一网络中的源标识，所述装置储存有所述第一网络的切片标识与所述第二网络的切片标识之间的映射关系；
处理单元1402，用于根据所述源标识、所述映射关系，确定所述第一切片在所述第二网络中的目标标识；根据所述目标标识生成响应消息；
发送单元1403，用于发送所述响应消息。
一种可能的实施方式中，所述装置为所述第一网络中的源网络切片选择功能NSSF；
所述接收单元1401具体用于：接收来自第一网元的第一请求消息；
所述发送单元1403具体用于：向所述第一网元发送所述第一响应消息。
一种可能的实施方式中，所述第一网元为所述第一网络中的源AMF或源网络存储库功能NRF。
一种可能的实施方式中，所述装置为所述第二网络中的目标NSSF；
所述接收单元1401具体用于：接收来自所述第一网络中的源NSSF的第二请求消息；
所述发送单元1403具体用于：向所述源NSSF发送所述第二响应消息。
上述方法实施例涉及的各步骤的所有相关内容均可以援引到对应功能模块的功能描述，在此不再赘述。
基于同一技术构思，参见图15，本申请实施例还提供一种通信装置1500，包括：
至少一个处理器1501；以及与所述至少一个处理器1501通信连接的通信接口1503；所述至少一个处理器1501通过执行存储器1502存储的指令，使得所述装置通过所述通信接口1503执行图7-12所示实施例中第一网元所执行的方法步骤。
可选的，所述存储器1502位于所述装置1500之外。
可选的，所述装置1500包括所述存储器1502，所述存储器1502与所述至少一个处理器1501相连，所述存储器1502存储有可被所述至少一个处理器1501执行的指令。
可选的，所述存储器1502位于所述装置1500之外。
可选的，所述装置1500包括所述存储器1502，所述存储器1502与所述至少一个处理器1501相连，所述存储器1502存储有可被所述至少一个处理器1501执行的指令。附图15用虚线表示存储器1502对于装置1500是可选的。
其中，所述处理器1501和所述存储器1502可以通过接口电路耦合，也可以集成在一起，这里不做限制。
本申请实施例中不限定上述处理器1501、存储器1502以及通信接口1503之间的具体连接介质。本申请实施例在图15中以处理器1501、存储器1502以及通信接口1503之间通过总线1504连接，总线在图15中以粗线表示，其它部件之间的连接方式，仅是进行示意性说明，并不引以为限。所述总线可以分为地址总线、数据总线、控制总线等。为便于表示，图15中仅用一条粗线表示，但并不表示仅有一根总线或一种类型的总线。
基于同一技术构思，参见图16，本申请实施例还提供一种通信装置1600，包括：
至少一个处理器1601；以及与所述至少一个处理器1601通信连接的通信接口1603；所述至少一个处理器1601通过执行存储器1602存储的指令，使得所述装置通过所述通信接口1603执行图7-12所示实施例中第二网元所执行的方法步骤。
可选的，所述存储器1602位于所述装置1600之外。
可选的，所述装置1600包括所述存储器1602，所述存储器1602与所述至少一个处理器1601相连，所述存储器1602存储有可被所述至少一个处理器1601执行的指令。
可选的，所述存储器1602位于所述装置1600之外。
可选的，所述装置1600包括所述存储器1602，所述存储器1602与所述至少一个处理器1601相连，所述存储器1602存储有可被所述至少一个处理器1601执行的指令。附图16用虚线表示存储器1602对于装置1600是可选的。
其中，所述处理器1601和所述存储器1602可以通过接口电路耦合，也可以集成在一起，这里不做限制。
本申请实施例中不限定上述处理器1601、存储器1602以及通信接口1603之间的具体连接介质。本申请实施例在图16中以处理器1601、存储器1602以及通信接口1603之间通过总线1604连接，总线在图16中以粗线表示，其它部件之间的连接方式，仅是进行示意性说明，并不引以为限。所述总线可以分为地址总线、数据总线、控制总线等。为便于表示，图16中仅用一条粗线表示，但并不表示仅有一根总线或一种类型的总线。
应理解，本申请实施例中提及的处理器可以通过硬件实现也可以通过软件实现。当通过硬件实现时，该处理器可以是逻辑电路、集成电路等。当通过软件实现时，该处理器可以是一个通用处理器，通过读取存储器中存储的软件代码来实现。
示例性的，处理器可以是中央处理单元(Central Processing Unit，CPU)，还可以是其他通用处理器、数字信号处理器(Digital Signal Processor，DSP)、专用集成电路(Application  Specific Integrated Circuit，ASIC)、现成可编程门阵列(Field Programmable Gate Array，FPGA)或者其他可编程逻辑器件、分立门或者晶体管逻辑器件、分立硬件组件等。通用处理器可以是微处理器或者该处理器也可以是任何常规的处理器等。
应理解，本申请实施例中提及的存储器可以是易失性存储器或非易失性存储器，或可包括易失性和非易失性存储器两者。其中，非易失性存储器可以是只读存储器(Read-Only Memory，ROM)、可编程只读存储器(Programmable ROM，PROM)、可擦除可编程只读存储器(Erasable PROM，EPROM)、电可擦除可编程只读存储器(Electrically EPROM，EEPROM)或闪存。易失性存储器可以是随机存取存储器(Random Access Memory，RAM)，其用作外部高速缓存。通过示例性但不是限制性说明，许多形式的RAM可用，例如静态随机存取存储器(Static RAM，SRAM)、动态随机存取存储器(Dynamic RAM，DRAM)、同步动态随机存取存储器(Synchronous DRAM，SDRAM)、双倍数据速率同步动态随机存取存储器(Double Data Eate SDRAM，DDR SDRAM)、增强型同步动态随机存取存储器(Enhanced SDRAM，ESDRAM)、同步连接动态随机存取存储器(Synchlink DRAM，SLDRAM)和直接内存总线随机存取存储器(Direct Rambus RAM，DR RAM)。
需要说明的是，当处理器为通用处理器、DSP、ASIC、FPGA或者其他可编程逻辑器件、分立门或者晶体管逻辑器件、分立硬件组件时，存储器(存储模块)可以集成在处理器中。
应注意，本文描述的存储器旨在包括但不限于这些和任意其它适合类型的存储器。
基于同一技术构思，本申请实施例还提供一种计算机可读存储介质，包括程序或指令，当所述程序或指令在计算机上运行时，使得如图7-12所示实施例中第一网元所执行的方法被执行。
基于同一技术构思，本申请实施例还提供一种计算机可读存储介质，包括程序或指令，当所述程序或指令在计算机上运行时，使得如图7-12所示实施例中第二网元所执行的方法被执行。
基于同一技术构思，本申请实施例还提供一种芯片，所述芯片与存储器耦合，用于读取并执行所述存储器中存储的程序指令，使得如图7-12所示实施例中第一网元所执行的方法被执行。
基于同一技术构思，本申请实施例还提供一种芯片，所述芯片与存储器耦合，用于读取并执行所述存储器中存储的程序指令，使得如图7-12所示实施例中第二网元所执行的方法被执行。
基于同一技术构思，本申请实施例还提供一种计算机程序产品，包括指令，当其在计算机上运行时，使得如图7-12所示实施例中第一网元所执行的方法被执行。
基于同一技术构思，本申请实施例还提供一种计算机程序产品，包括指令，当其在计算机上运行时，使得如图7-12所示实施例中第二网元所执行的方法被执行。
上述方法实施例涉及的各步骤的所有相关内容均可以援引到对应功能模块的功能描述，在此不再赘述。
由于本申请实施例提供的通信装置1300、通信装置1400、通信装置1500、通信装置1600可用于执行图7-12所示的实施例中相应的实施例所提供的方法，因此其所能获得的技术效果可参考上述方法实施例，在此不再赘述。
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 (24)

  1. 一种发现目标接入和移动性管理功能AMF的方法，其特征在于，包括：
    当终端设备需要从第一网络中的源接入网设备切换至第二网络中的目标接入网设备时，所述第一网络中的第一网元获取所述终端设备在所述第一网络中的第一切片在所述第二网络中的目标标识；
    所述第一网元基于所述目标标识确定所述第二网络中的目标AMF，其中所述目标AMF支持所述第一切片。
  2. 如权利要求1所述的方法，其特征在于，所述第一网络中的第一网元获取所述终端设备在所述第一网络中的第一切片在所述第二网络中的目标标识，包括：
    所述第一网元向所述第一网络中的源网络切片选择功能NSSF发送第一请求消息，所述第一请求消息中包含所述第一切片在所述第一网络中的源标识；
    所述第一网元接收来自所述源NSSF的第一响应消息，所述第一响应消息中包括所述第一切片在所述第二网络中的目标标识，其中，所述第二网络支持所述第一切片。
  3. 如权利要求2所述的方法，其特征在于，
    所述源NSSF储存有所述第一网络的切片标识与所述第二网络的切片标识之间的映射关系；或者，
    所述第二网络中的目标NSSF储存有所述第一网络的切片标识与所述第二网络的切片标识之间的映射关系，所述第一响应消息是所述源NSSF根据从所述目标NSSF查询到的所述第一切片在所述第二网络中的目标标识生成的。
  4. 如权利要求1所述的方法，其特征在于，所述第一网络中的第一网元获取所述终端设备在所述第一网络中的第一切片在所述第二网络中的目标标识，包括：
    所述第一网元根据所述第一切片在所述第一网络中的源标识、所述第一网络的切片标识与所述第二网络的切片标识之间的映射关系，确定所述第一切片在所述第二网络中的目标标识。
  5. 如权利要求4所述的方法，其特征在于，所述第一网元储存所述第一网络的切片标识与所述第二网络的切片标识之间的映射关系。
  6. 如权利要求1-5任一项所述的方法，其特征在于，所述第一网元为所述第一网络中的源AMF或源网络存储库功能NRF。
  7. 如权利要求1-5任一项所述的方法，其特征在于，在所述第一网络中的第一网元获取所述终端设备在所述第一网络中的第一切片在所述第二网络中的目标标识之前，所述方法还包括：
    所述第一网元确定所述第一网络的公共陆地移动网PLMN标识和所述第二网络的PLMN标识不同；或者，
    所述第一网元确定所述第一网络的PLMN标识和所述第二网络的PLMN标识相同且所述第一网络的跟踪区标识TAI和所述第二网络的TAI不同。
  8. 一种发现目标接入和移动性管理功能AMF的方法，其特征在于，包括：
    当终端设备需要从第一网络中的源接入网设备切换至第二网络中的目标接入网设备时，第二网元接收请求消息，其中所述请求消息中包含所述终端设备在所述第一网络中的第一切片在所述第一网络中的源标识，所述第二网元储存有所述第一网络的切片标识与所 述第二网络的切片标识之间的映射关系；
    所述第二网元根据所述源标识、所述映射关系，确定所述第一切片在所述第二网络中的目标标识；
    所述第二网元根据所述目标标识生成响应消息，所述第二网元发送所述响应消息。
  9. 如权利要求8所述的方法，其特征在于，所述第二网元为所述第一网络中的源网络切片选择功能NSSF；
    所述第二网元接收请求消息，包括：
    所述源NSSF接收来自第一网元的第一请求消息；
    所述第二网元根据所述目标标识生成响应消息，所述第二网元发送所述响应消息，包括：
    所述源NSSF根据所述目标标识生成第一响应消息，所述源NSSF向所述第一网元发送所述第一响应消息。
  10. 如权利要求9所述的方法，其特征在于，所述第一网元为所述第一网络中的源AMF或源网络存储库功能NRF。
  11. 如权利要求8所述的方法，其特征在于，所述第二网元为所述第二网络中的目标NSSF；
    所述第二网元接收请求消息，包括：
    所述目标NSSF接收来自所述第一网络中的源NSSF的第二请求消息；
    所述第二网元根据所述目标标识生成响应消息，所述第二网元发送所述响应消息，包括：
    所述目标NSSF根据所述目标标识生成第二响应消息，所述目标NSSF向所述源NSSF发送所述第二响应消息。
  12. 一种通信装置，其特征在于，所述装置位于第一网络，所述装置包括：
    获取单元，用于当终端设备需要从所述第一网络中的源接入网设备切换至第二网络中的目标接入网设备时，获取所述终端设备在所述第一网络中的第一切片在所述第二网络中的目标标识；
    确定单元，用于基于所述目标标识确定所述第二网络中的目标AMF，其中所述目标AMF支持所述第一切片。
  13. 如权利要求12所述的装置，其特征在于，所述获取单元具体用于：
    向所述第一网络中的源网络切片选择功能NSSF发送第一请求消息，所述第一请求消息中包含所述第一切片在所述第一网络中的源标识；
    接收来自所述源NSSF的第一响应消息，所述第一响应消息中包括所述第一切片在所述第二网络中的目标标识，其中，所述第二网络支持所述第一切片。
  14. 如权利要求13所述的装置，其特征在于，
    所述源NSSF储存有所述第一网络的切片标识与所述第二网络的切片标识之间的映射关系；或者，
    所述第二网络中的目标NSSF储存有所述第一网络的切片标识与所述第二网络的切片标识之间的映射关系，所述第一响应消息是所述源NSSF根据从所述目标NSSF查询到的所述第一切片在所述第二网络中的目标标识生成的。
  15. 如权利要求12所述的装置，其特征在于，所述获取单元具体用于：
    根据所述第一切片在所述第一网络中的源标识、所述第一网络的切片标识与所述第二网络的切片标识之间的映射关系，确定所述第一切片在所述第二网络中的目标标识。
  16. 如权利要求15所述的装置，其特征在于，所述装置还包括储存单元，用于储存所述第一网络的切片标识与所述第二网络的切片标识之间的映射关系。
  17. 如权利要求12-16任一项所述的装置，其特征在于，所述装置为所述第一网络中的源AMF或源网络存储库功能NRF。
  18. 如权利要求12-16任一项所述的装置，其特征在于，所述确定单元还用于：
    在所获取单元获取所述终端设备在所述第一网络中的第一切片在所述第二网络中的目标标识之前，确定所述第一网络的公共陆地移动网PLMN标识和所述第二网络的PLMN标识不同；或者，确定所述第一网络的PLMN标识和所述第二网络的PLMN标识相同且所述第一网络的跟踪区标识TAI和所述第二网络的TAI不同。
  19. 一种通信装置，其特征在于，所述装置位于第一网络或第二网络，所述装置包括：
    接收单元，用于当终端设备需要从所述第一网络中的源接入网设备切换至所述第二网络中的目标接入网设备时，接收请求消息，其中所述请求消息中包含所述终端设备在所述第一网络中的第一切片在所述第一网络中的源标识，所述装置储存有所述第一网络的切片标识与所述第二网络的切片标识之间的映射关系；
    处理单元，用于根据所述源标识、所述映射关系，确定所述第一切片在所述第二网络中的目标标识；根据所述目标标识生成响应消息；
    发送单元，用于发送所述响应消息。
  20. 如权利要求19所述的装置，其特征在于，所述装置为所述第一网络中的源网络切片选择功能NSSF；
    所述接收单元具体用于：接收来自第一网元的第一请求消息；
    所述发送单元具体用于：向所述第一网元发送所述第一响应消息。
  21. 如权利要求20所述的装置，其特征在于，所述第一网元为所述第一网络中的源AMF或源网络存储库功能NRF。
  22. 如权利要求19所述的装置，其特征在于，所述装置为所述第二网络中的目标NSSF；
    所述接收单元具体用于：接收来自所述第一网络中的源NSSF的第二请求消息；
    所述发送单元具体用于：向所述源NSSF发送所述第二响应消息。
  23. 一种通信装置，其特征在于，包括：
    至少一个处理器；以及与所述至少一个处理器通信连接的存储器、通信接口；
    其中，所述存储器存储有可被所述至少一个处理器执行的指令，所述至少一个处理器通过执行所述存储器存储的指令，使得所述装置通过所述通信接口执行如权利要求1-7或8-11中任一项所述的方法。
  24. 一种计算机可读存储介质，其特征在于，包括程序或指令，当所述程序或指令在计算机上运行时，使得如权利要求1-7或8-11中任一项所述的方法被执行。
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116489731A (zh) * 2023-06-21 2023-07-25 中国电信股份有限公司 切片信息映射方法、装置、计算机设备和存储介质

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108323245A (zh) * 2017-06-19 2018-07-24 华为技术有限公司 一种注册及会话建立的方法、终端和amf实体
CN109314917A (zh) * 2017-05-09 2019-02-05 华为技术有限公司 网络切片选择策略更新方法、及装置
CN109429295A (zh) * 2017-08-31 2019-03-05 中兴通讯股份有限公司 一种选择amf的方法、amf、系统及存储介质
CN110677884A (zh) * 2018-07-03 2020-01-10 中国电信股份有限公司 终端、网络接入方法、装置、系统和计算机可读存储介质
US20200029264A1 (en) * 2018-07-20 2020-01-23 Google Llc Network slicing for wlan

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR102210896B1 (ko) * 2016-11-04 2021-02-01 후아웨이 테크놀러지 컴퍼니 리미티드 네트워크 간 변경 방법 및 장치, 그리고 관련 장치
CN109413702A (zh) * 2017-08-16 2019-03-01 中国移动通信有限公司研究院 一种网络切换方法、装置及核心网
CN110691384B (zh) * 2019-10-23 2022-09-27 中国联合网络通信集团有限公司 一种网络切片使用方法及装置

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109314917A (zh) * 2017-05-09 2019-02-05 华为技术有限公司 网络切片选择策略更新方法、及装置
CN108323245A (zh) * 2017-06-19 2018-07-24 华为技术有限公司 一种注册及会话建立的方法、终端和amf实体
CN109429295A (zh) * 2017-08-31 2019-03-05 中兴通讯股份有限公司 一种选择amf的方法、amf、系统及存储介质
CN110677884A (zh) * 2018-07-03 2020-01-10 中国电信股份有限公司 终端、网络接入方法、装置、系统和计算机可读存储介质
US20200029264A1 (en) * 2018-07-20 2020-01-23 Google Llc Network slicing for wlan

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
HUAWEI, HISILICON, ERICSSON: "OI#4h: TS 23.501: Selection of a Target AMF supporting the Network Slices due to UE mobility", 3GPP DRAFT; S2-179431_9351_8399_OI#4H TS23 501_INTER REGION MOBILITY V1.4, 3RD GENERATION PARTNERSHIP PROJECT (3GPP), MOBILE COMPETENCE CENTRE ; 650, ROUTE DES LUCIOLES ; F-06921 SOPHIA-ANTIPOLIS CEDEX ; FRANCE, vol. SA WG2, no. Reno, Nevada, USA; 20171127 - 20171201, 1 December 2017 (2017-12-01), Mobile Competence Centre ; 650, route des Lucioles ; F-06921 Sophia-Antipolis Cedex ; France , XP051365958 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116489731A (zh) * 2023-06-21 2023-07-25 中国电信股份有限公司 切片信息映射方法、装置、计算机设备和存储介质
CN116489731B (zh) * 2023-06-21 2023-09-29 中国电信股份有限公司 切片信息映射方法、装置、计算机设备和存储介质

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