Standby smf discovery method, apparatus, electronic device, and medium

Abstract

This disclosure provides a method for discovering a backup SMF (Service Provider Function). The method involves receiving a discovery request message from an NF (Network Function), obtaining selection parameters carried within the message, and the NF sending the discovery request message when it detects a failure of the first SMF corresponding to the current session. The selection parameters include the identifier of the SMF group and service parameters. Based on the mapping relationship between the SMF information and the selection parameters, the method determines the information of the second SMF corresponding to the selection parameters. The first and second SMFs belong to the same SMF group and the same SMF cluster. SMFs within the same SMF cluster are mutually primary / backup, manage the same session, and are configured with the same selection parameters. Finally, an NF discovery response message carrying the information of the second SMF is sent to the NF. In this embodiment, when an SMF fails, the backup SMF can be quickly determined based on this mapping relationship, simplifying the backup SMF discovery process, improving system performance and backup SMF discovery efficiency, saving resources, and avoiding network overload. This disclosure also provides an apparatus, a computer device, and a readable medium.

Description

Technical Field

[0001] This disclosure relates to the field of communication technology, and specifically to a backup SMF discovery method, apparatus, electronic device, and medium. Background Technology

[0002] Vertical industry applications (such as coal mines, power, and industrial control) require ultra-high reliability and ultra-low latency. 3GPP (3rd Generation Partnership Project) classifies these scenarios into uRLLC (Ultra-Reliable and Low-Latency Communication) and proposes an end-to-end session redundancy scheme to improve reliability. This scheme establishes two PDU Sessions (Protocol Data Units) between the UE (User Equipment) and the enterprise application network.

[0003] In the uRLLC dual PDU session redundancy scheme, the two redundant PDU sessions need to be established on two different SMFs (Session Management Functions). When these two SMFs are in an SMFSet (SMF group), if one of the SMFs fails, and the Network Function (NF) node arbitrarily selects an SMF from the SMF group as a backup SMF, it is possible that the two redundant PDU sessions will be connected to the same SMF. This does not meet the end-to-end redundancy requirement and reduces reliability. After selecting a backup SMF, to ensure that the two redundant PDU sessions can be located on two different SMFs, a backup SMF discovery scheme exists. When an SMF fails, it first obtains information on all SMFs in the SMF group containing the failed SMF, and then selects a backup SMF from them. However, this scheme's process for selecting a backup SMF is relatively complex. uRLLC is widely used in vertical industries and therefore has a large number of users. For an SMF that carries millions of sessions, if the above-mentioned solution is used to reselect a backup SMF after a failure, the complex processing procedure described above needs to be executed for each session. This will consume a lot of resources and may even cause the core network to overload. Summary of the Invention

[0004] This disclosure provides a backup SMF discovery method, apparatus, electronic device, and medium.

[0005] In a first aspect, embodiments of this disclosure provide a backup SMF discovery method, comprising: in response to receiving an NF discovery request message sent by a network functional node (NF), obtaining selection parameters carried therein, wherein the NF discovery request message is sent by the NF when it detects a failure of a first session management function entity (SMF) corresponding to the current session, and the selection parameters include an identifier of an SMF group and service parameters, wherein the identifier of the SMF group is the identifier of the group to which the first SMF belongs;

[0006] Based on the mapping relationship between the SMF information and the selection parameters, the information of the second SMF corresponding to the selection parameters is determined. The first SMF and the second SMF belong to the same SMF cluster of the same SMF group. The SMFs in the same SMF cluster are mutually primary and backup, manage the same session, and are configured with the same selection parameters.

[0007] Send an NF discovery response message carrying information about the second SMF to the NF.

[0008] In some embodiments, the method further includes:

[0009] In response to receiving an NF registration request message from SMF, retrieve the selection parameters carried therein;

[0010] Establish a mapping relationship between the selection parameters and the information of the SMF.

[0011] In some embodiments, the service parameter is a redundant sequence number (RSN).

[0012] In some embodiments, an SMF group includes at least two SMF clusters, and the selection parameters of SMFs belonging to different SMF clusters are different.

[0013] In another aspect, embodiments of this disclosure also provide an alternative SMF discovery method, including:

[0014] In response to detecting a failure of the first session management function entity (SMF) corresponding to the current session, a network function node (NF) discovery request message is sent to the network data warehouse function entity (NRF). The NF discovery request message carries selection parameters for the first SMF, including the identifier of the SMF group and service parameters. The identifier of the SMF group is the identifier of the group to which the first SMF belongs.

[0015] The system receives the NF discovery response message sent by the NRF, obtains the information of the second SMF carried therein, and determines the backup SMF based on the information of the second SMF. The information of the second SMF is determined by the NRF based on the mapping relationship between the information of the SMF and the selection parameters and the selection parameters.

[0016] The first SMF and the second SMF belong to the same SMF cluster within the same SMF group. The SMFs within the same SMF cluster are mutually primary and backup, manage the same session, and are configured with the same selection parameters.

[0017] In some embodiments, determining the backup SMF based on the information of the second SMF includes:

[0018] In response to obtaining information from at least two second SMFs, information from one second SMF is randomly selected from the information of the second SMFs, and a backup SMF is determined based on the selected second SMF information.

[0019] In some embodiments, before sending an NF discovery request message to the Network Data Warehouse Functional Entity (NRF), the method further includes:

[0020] During the session establishment process, the selection parameters sent by the first SMF are received.

[0021] In some embodiments, receiving the selection parameters sent by the first SMF includes:

[0022] When the Network Function Node (NF) is a User Plane Function Entity (UPF), it receives an N4 session establishment message carrying the selection parameters sent by the first SMF.

[0023] When the network functional node (NF) is a policy control function entity (PCF), it receives a session management policy association establishment message carrying the selection parameters sent by the first SMF.

[0024] In some embodiments, the service parameter is a redundant sequence number (RSN).

[0025] In some embodiments, an SMF group includes at least two SMF clusters, and the selection parameters of SMFs belonging to different SMF clusters are different.

[0026] In another aspect, embodiments of this disclosure also provide an alternative SMF discovery method, including:

[0027] Send a Network Function Node (NF) registration request message to the Network Data Warehouse Functional Entity (NRF). The NF registration request message carries the selection parameters of this SMF, so that the NRF can establish a mapping relationship between the information of this SMF and the selection parameters. The selection parameters include the identifier of the SMF group to which this SMF belongs and service parameters.

[0028] This SMF belongs to an SMF cluster within an SMF group. SMFs within the same SMF cluster are in a primary / backup relationship with each other, manage the same session, and are configured with the same selection parameters.

[0029] In some embodiments, the method further includes:

[0030] During the session establishment process, in response to receiving a session establishment request message from the user equipment, the selection parameters are sent to the network function node (NF) of the session.

[0031] In some embodiments, sending the selection parameters to the Network Function Node (NF) of the session includes:

[0032] In the case that the NF is a User Plane Function Entity (UPF), an N4 session establishment message carrying the selection parameters is sent to the UPF.

[0033] In the case that the NF is a Policy Control Function Entity (PCF), a Session Management Policy Association Establishment Message carrying the selection parameters is sent to the PCF.

[0034] In some embodiments, the service parameter is a redundant sequence number (RSN).

[0035] In some embodiments, an SMF group includes at least two SMF clusters, and the selection parameters of SMFs belonging to different SMF clusters are different.

[0036] In another aspect, this disclosure also provides a network data warehouse functional entity, including a receiving module, an acquisition module, a discovery module, and a sending module. The receiving module is used to receive an NF discovery request message sent by a network functional node (NF). The NF discovery request message is sent by the NF when it detects a failure of the first session management functional entity (SMF) corresponding to the current session.

[0037] The acquisition module is used to acquire the selection parameters carried in the NF discovery request message. The selection parameters include the identifier of the SMF group and service parameters. The identifier of the SMF group is the identifier of the group to which the first SMF belongs.

[0038] The discovery module is used to determine the information of the second SMF corresponding to the selection parameter based on the mapping relationship between the SMF information and the selection parameter. The first SMF and the second SMF belong to the same SMF cluster of the same SMF group. The SMFs in the same SMF cluster are mutually primary and backup, manage the same session, and are configured with the same selection parameter.

[0039] The sending module is used to send an NF discovery response message carrying information of the second SMF to the NF.

[0040] In another aspect, embodiments of this disclosure also provide a network functional node, including a sending module, a receiving module, and a determining module. The sending module is used to send a network functional node (NF) discovery request message to a network data warehouse functional entity (NRF) in response to detecting a fault in the first session management functional entity (SMF) corresponding to the current session. The NF discovery request message carries selection parameters for the first SMF, and the selection parameters include the identifier of the SMF group and service parameters. The identifier of the SMF group is the identifier of the group to which the first SMF belongs.

[0041] The receiving module is used to receive the NF discovery response message sent by the NRF;

[0042] The determining module is used to obtain the information of the second SMF carried therein, and determine the backup SMF based on the information of the second SMF. The information of the second SMF is determined by the NRF based on the mapping relationship between the information of the SMF and the selection parameters and the selection parameters. The first SMF and the second SMF belong to the same SMF cluster of the same SMF group. The SMFs in the same SMF cluster are mutually primary and backup, manage the same session, and are configured with the same selection parameters.

[0043] In another aspect, this disclosure also provides a session management function entity, including a registration module. The registration module is used to send a network function node (NF) registration request message to a network data warehouse function entity (NRF). The NF registration request message carries selection parameters of the current SMF, so that the NRF can establish a mapping relationship between the information of the current SMF and the selection parameters. The selection parameters include the identifier of the SMF group to which the current SMF belongs and service parameters.

[0044] This SMF belongs to an SMF cluster within an SMF group. SMFs within the same SMF cluster are in a primary / backup relationship with each other, manage the same session, and are configured with the same selection parameters.

[0045] In another aspect, embodiments of this disclosure also provide an electronic device, including:

[0046] One or more processors;

[0047] A storage device on which one or more programs are stored;

[0048] When the one or more programs are executed by the one or more processors, the one or more processors implement the alternative SMF discovery method as described above.

[0049] In another aspect, embodiments of this disclosure also provide a computer-readable medium having a computer program stored thereon, wherein the program, when executed, implements the alternative SMF discovery method as described above.

[0050] This disclosure provides a backup SMF discovery method. The method involves receiving a discovery request message from an NF (Network Function), obtaining selection parameters carried therein, whereby the NF sends the NF when it detects a failure in the first SMF corresponding to the current session. The selection parameters include an SMF group identifier and service parameters, with the SMF group identifier being the identifier of the group to which the first SMF belongs. Based on the mapping relationship between SMF information and the selection parameters, the method determines the information of the second SMF corresponding to the selection parameters. The first and second SMFs belong to the same SMF cluster within the same SMF group. SMFs within the same SMF cluster are mutually primary / backup, manage the same session, and are configured with the same selection parameters. Finally, the method sends an NF discovery response message carrying the information of the second SMF to the NF. This embodiment of the disclosure configures the same selection parameters for each SMF in a primary / backup relationship. The selection parameters include the identifier of the SMF group and service parameters, and a mapping relationship between SMF information and selection parameters is pre-established. When an SMF fails, the backup SMF can be quickly determined based on the mapping relationship, without having to obtain information on all SMFs in the SMF group where the failed SMF is located. This simplifies the backup SMF discovery process, improves system performance and backup SMF discovery efficiency, saves resources, and avoids network overload. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the system architecture provided for an embodiment of the present disclosure;

[0052] Figure 2 A flowchart illustrating the backup SMF discovery method with NRF as the execution subject provided in this embodiment of the disclosure;

[0053] Figure 3 A schematic diagram illustrating the process of SMF registration with NRF provided in this embodiment of the disclosure;

[0054] Figure 4 A flowchart illustrating the alternative SMF discovery method with NF as the execution subject provided in this embodiment of the disclosure;

[0055] Figure 5 A flowchart illustrating an alternative SMF discovery method with SMF as the execution entity, provided in an embodiment of this disclosure;

[0056] Figure 6 Signaling flowchart of the backup SMF discovery method for UPF1 detecting SMF1 fault provided in the embodiments of this disclosure;

[0057] Figure 7 Signaling flowchart of the backup SMF discovery method for detecting SMF1 faults in PDF provided in this embodiment of the disclosure;

[0058] Figure 8 This is a schematic diagram of the signaling flow for SMF registration with NRF provided in an embodiment of this disclosure;

[0059] Figure 9 A schematic diagram of the NRF structure provided in the embodiments of this disclosure. Figure 1 ;

[0060] Figure 10 A schematic diagram of the NRF structure provided in the embodiments of this disclosure. Figure 2 ;

[0061] Figure 11 This is a schematic diagram of the structure of NF provided in the embodiments of this disclosure;

[0062] Figure 12 Structural diagram of the SMF provided in the embodiments of this disclosure Figure 1 ;

[0063] Figure 13 Structural diagram of the SMF provided in the embodiments of this disclosure Figure 2 . Detailed Implementation

[0064] Exemplary embodiments will be described more fully below with reference to the accompanying drawings; however, these exemplary embodiments may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will enable those skilled in the art to fully understand the scope of this disclosure.

[0065] As used herein, the term “and / or” includes any and all combinations of one or more related enumerated entries.

[0066] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. As used herein, the singular forms “a” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It will also be understood that when the terms “comprising” and / or “made of” are used in this specification, the presence of the said feature, integral, step, operation, element, and / or component is specified, but the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof is not excluded.

[0067] The embodiments described herein can be described with reference to plan views and / or cross-sectional views using the ideal schematic diagrams of this disclosure. Therefore, the example illustrations can be modified according to manufacturing techniques and / or tolerances. Therefore, the embodiments are not limited to those shown in the drawings, but include modifications to configurations formed based on manufacturing processes. Therefore, the areas illustrated in the drawings are schematic in nature, and the shapes of the areas shown in the figures illustrate specific shapes of areas of an element, but are not intended to be limiting.

[0068] Unless otherwise specified, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and this disclosure, and will not be interpreted as having an idealized or overly formal meaning, unless expressly so defined herein.

[0069] In uRLLC dual-PDU session scenarios, an SMF group comprises multiple SMFs, and the NFs within the SMF group are mutually disaster-tolerant. A traditional backup SMF discovery scheme is as follows: two redundant PDU sessions correspond to different S-NSSAI (Single Network Slice Selection Assistance Information) + DNN (Digital Data Network) combination parameters. When an SMF fails, the NF obtains information on all SMFs within the SMF group and then further selects a suitable backup SMF based on the S-NSSAI + DNN combination parameters of the current session. This scheme requires at least two key steps: first, obtaining information on all SMFs within the SMF group containing the failed SMF; second, selecting a backup SMF from all SMFs obtained in the previous step based on the S-NSSAI + DNN combination parameters. This backup SMF discovery process is complex and consumes significant resources.

[0070] Therefore, this disclosure provides an alternative SMF discovery method, which can be applied to, for example... Figure 1 In the system shown, such as Figure 1 As shown, the system includes at least: NRF (Network Repository Function), PCF (Policy Control Function), UE, access equipment (NG-RAN, 5G access network), UPF (User Plane Function), DN (Data Network), and SMF. UPF and PCF are collectively referred to as NF. Multiple SMFs form an SMF group, which can be divided according to ToC (enterprise-oriented) or ToB (individual-oriented). There can be multiple SMF groups. The backup SMF discovery method of this disclosure embodiment can be applied to uRLLC dual PDU session redundancy scenarios, such as... Figure 1As shown, two redundant PDU sessions are established on different SMFs within the same SMF group. PDU session 1 is established on SMF2 via UPF1, and PDU session 2 is established on SMF4 via UPF2. The UE is a terminal for a vertical industry. For the same vertical industry service, two redundant PDU sessions can be established using independent combined parameters of S-NSSAI+DNN. The Master NG-RAN and Secondary NG-RAN serve the user plane paths of the two redundant PDU sessions established for the vertical industry service, respectively. UPF1 and UPF2 serve the user plane paths of the two redundant PDU sessions established for the vertical industry service, respectively, and are used to provide data forwarding and to discover the backup SMF of the failed SMF in the event of an SMF failure. SMF1 and SMF2 can provide session management for PDU session 1, and SMF3 and SMF4 can provide session management for the other redundant PDU session (i.e., PDU session 2). The NRF provides SMF registration and SMF discovery functions. The PCF is a policy and charging control decision node, used to discover the backup SMF when an SMF (such as SMF1) fails.

[0071] like Figure 2 As shown, the alternative SMF discovery method provided in this disclosure includes the following steps:

[0072] Step 11: In response to receiving the NF discovery request message sent by the NF, obtain the selection parameters carried therein. The NF discovery request message is sent by the NF when it detects the first SMF failure corresponding to the current session. The selection parameters include the SMF group identifier and service parameters. The SMF group identifier is the identifier of the group to which the first SMF belongs.

[0073] When the NF detects a failure in the first SMF corresponding to the current session, it sends an NF discovery request message carrying selection parameters to the NRF. These selection parameters are a combination of identification service parameters for the SMF group, where the identifier is the identifier of the SMF group to which the failed first SMF belongs. In this step, the NRF retrieves the selection parameters carried in the received NF discovery request message. The NF can be a UPF or a PCF. A PDU session requires direct or indirect interaction between the UPF and PCF and the SMF managing the PDU session. Therefore, once an SMF fails, it can be detected by the UPF and PCF managing the PDU session.

[0074] Step 12: Based on the mapping relationship between the SMF information and the selection parameters, determine the information of the second SMF corresponding to the selection parameters. The first SMF and the second SMF belong to the same SMF cluster of the same SMF group. The SMFs in the same SMF cluster are mutually primary and backup, manage the same session, and are configured with the same selection parameters.

[0075] In this embodiment of the disclosure, a mapping relationship between SMF information and selection parameters is pre-established in the NRF. For example, the SMF information can be an SMF identifier. An SMF group can be divided into at least one SMF cluster. An SMF cluster includes at least two SMFs with a primary / backup relationship. Each SMF within the same SMF cluster manages the same PDU session and is configured with the same selection parameters. For example, as... Figure 1 As shown, the SMF group comprises two SMF clusters. SMF cluster 1 includes SMF1 and SMF2, which are mutually primary and backup, and manage PDU session 1. SMF cluster 2 includes SMF3 and SMF4, which are mutually primary and backup, and manage PDU session 2. Figure 1 The two redundant PDU sessions shown belong to the same SMF group. Therefore, the SMF group identifiers in the selection parameters of PDU session 1 and PDU session 2 are the same, but the service parameters are different.

[0076] Since SMFs belonging to the same SMF cluster and having a mutual primary / backup relationship have the same selection parameters, and a mapping relationship between SMF information and selection parameters is pre-established, each SMF within the same SMF cluster corresponds to the same selection parameter. In this step, the NRF can determine other backup SMFs belonging to the same SMF cluster as the first SMF by querying this mapping relationship based on the selection parameters.

[0077] Step 13: Send an NF discovery response message carrying information about the second SMF to the NF.

[0078] In this step, the NRF carries the information of the second SMF obtained from the query in the NF discovery response message and sends it to the NF so that the NF can determine the backup SMF based on the information of the second SMF.

[0079] The backup SMF discovery method provided in this embodiment receives a discovery request message sent by an NF, obtains the selection parameters carried therein, the NF discovery request message is sent by the NF when it detects a failure of the first SMF corresponding to the current session, the selection parameters include the identifier of the SMF group and service parameters, the identifier of the SMF group is the identifier of the group to which the first SMF belongs; according to the mapping relationship between the SMF information and the selection parameters, the information of the second SMF corresponding to the selection parameters is determined, the first SMF and the second SMF belong to the same SMF cluster of the same SMF group, the SMFs in the same SMF cluster are mutually primary and backup, manage the same session, and are configured with the same selection parameters; and an NF discovery response message carrying the information of the second SMF is sent to the NF. This embodiment of the disclosure configures the same selection parameters for each SMF in a primary / backup relationship. The selection parameters include the identifier of the SMF group and service parameters, and a mapping relationship between SMF information and selection parameters is pre-established. When an SMF fails, the backup SMF can be quickly determined based on the mapping relationship, without having to obtain information on all SMFs in the SMF group where the failed SMF is located. This simplifies the backup SMF discovery process, improves system performance and backup SMF discovery efficiency, saves resources, and avoids network overload.

[0080] In some embodiments, the backup SMF discovery method further includes a step of establishing a mapping relationship between SMF information and selection parameters, which is established during SMF registration. The following is a continuation of this process. Figure 3 The process of establishing the mapping relationship between SMF information and selection parameters is explained in detail.

[0081] like Figure 3 As shown, establishing the mapping relationship between SMF information and selection parameters includes the following steps:

[0082] Step 21: In response to receiving the NF registration request message sent by SMF, obtain the selection parameters carried therein.

[0083] In this step, the SMF registers itself by sending an NF Registration Request message to the NRF. This NF Registration Request message carries an NF Profile, which includes the selection parameters for the SMF. The SMF may be either a first SMF or a second SMF.

[0084] Step 22: Establish the mapping relationship between the selection parameters and the SMF information.

[0085] In this step, for each currently registered SMF, the NRF establishes a mapping between the SMF's information and the selection parameters, and stores this mapping locally. It's important to note that each SMF must register with the NRF; therefore, the NRF can establish and store the mapping between each SMF's information and the corresponding selection parameters. This way, when the NF subsequently initiates SMF discovery with the NRF, it can directly find all matching SMFs (i.e., the second SMF) by carrying the selection parameters.

[0086] In some embodiments, after establishing the mapping relationship between the selection parameters and the SMF information (i.e., step 22), the alternative SMF discovery method may further include the following steps: returning an NF registration response message (NFRegisterResponse) to the SMF, the NF registration response message carrying an NF configuration file.

[0087] In some embodiments, the service parameter is used to represent the service scope that the SMF can serve. For example, the service parameter can be RSN (Redundancy Sequence Number), that is, the selection parameter is a combination of the SMF group identifier and RSN.

[0088] The RSN field is an existing field in the Nnrf interface message of NRF and the N4 / N7 interface message of SMF. Therefore, the RSN field of the above interface messages is extended by taking the combination parameter of SMF group identifier + RSN as the selection parameter and carrying it in the RSN field to realize the transmission of selection parameters. The modification to the existing protocol is small and the solution is easy to implement.

[0089] In some embodiments, an SMF group includes at least two SMF clusters, and the selection parameters of SMFs belonging to different SMF clusters are different. This is a scenario of redundant PDU sessions, where different SMF clusters manage one PDU session of the redundant PDU session. The selection parameters of each SMF in the same SMF cluster are the same, while the selection parameters of different SMF clusters are different, that is, the service parameters in the selection parameters are different (the identifier of the SMF group is the same).

[0090] In scenarios with redundant PDU sessions, the backup SMF discovery method provided in this disclosure can not only quickly and easily find the backup SMF of the faulty SMF, but also ensure that the redundant PDU sessions are still managed by different SMFs. That is, the backup SMF is not the same SMF that manages another redundant PDU session, thus meeting end-to-end redundancy requirements and ensuring reliability. Figure 1For example, if SMF1 fails, according to the scheme of this embodiment, only the backup SMF will be searched in the SMF cluster 1 where SMF1 is located, and SMF2 will be found as the backup SMF. SMF2 will manage PDU session 1. There will be no situation where the backup SMF is an SMF in SMF cluster 2, that is, PDU session 1 will not be migrated to the SMF cluster of PDU2.

[0091] It should be noted that the embodiments of this disclosure can also be applied to scenarios with non-redundant sessions, i.e., an SMF group includes only one SMF cluster, and the PDU sessions managed by each SMF in the SMF group do not have a redundant relationship. In this scenario, the backup SMF discovery method provided in the embodiments of this disclosure can also quickly and easily find the backup SMF of the failed SMF.

[0092] In this embodiment of the disclosure, when the service parameter is RSN, for vertical industry services, the two redundant PDU sessions correspond to two different RSN parameter values. It should be noted that the SMFs managing the two redundant PDU sessions belong to the same SMF group. Within an SMF group, for each SMF cluster, the SMFs within the cluster are configured with only one RSN parameter value, thereby ensuring that only one of the two redundant PDU sessions is managed, that is, the SMFs with a primary and backup relationship are configured with the same RSN parameter value.

[0093] This disclosure also provides an alternative SMF discovery method, such as... Figure 4 As shown, the backup SMF discovery method includes the following steps:

[0094] Step 31: In response to the detection of a first SMF failure corresponding to the current session, an NF discovery request message is sent to the NRF. The NF discovery request message carries selection parameters for the first SMF. The selection parameters include the identifier of the SMF group and service parameters. The identifier of the SMF group is the identifier of the group to which the first SMF belongs.

[0095] In this step, if the NF detects a first SMF failure, it sends an NF Discovery Request message carrying the selection parameters of the first SMF to the NRF, so that the NRF can look up the mapping relationship between the SMF information and the selection parameters. It should be noted that the NF can be a UPF or a PCF.

[0096] Step 32: Receive the NF discovery response message sent by the NRF, obtain the information of the second SMF carried therein, and determine the backup SMF based on the information of the second SMF. The information of the second SMF is determined by the NRF based on the mapping relationship between the information of the SMF and the selection parameters and the selection parameters. The first SMF and the second SMF belong to the same SMF cluster of the same SMF group. The SMFs in the same SMF cluster are mutually primary and backup, manage the same session, and are configured with the same selection parameters.

[0097] After the NRF determines the SMF information corresponding to the selection parameter, it returns an NF Discovery Response message to the NF. In this step, the NF obtains the information of the second SMF carried in the NF Discovery Response message and determines a backup SMF based on the information of the second SMF.

[0098] In this embodiment of the disclosure, a mapping relationship between SMF information and selection parameters is pre-established in the NRF. For example, the SMF information can be an SMF identifier. An SMF group includes at least one SMF cluster, and an SMF cluster includes at least two SMFs with a primary / backup relationship. Each SMF within the same SMF cluster manages the same PDU session and is configured with the same selection parameters. For example, as... Figure 1 As shown, the SMF group includes two SMF clusters. SMF cluster 1 includes SMF1 and SMF2, which are mutually primary and backup. SMF1 and SMF2 manage PDU session 1. SMF cluster 2 includes SMF3 and SMF4, which are mutually primary and backup. SMF3 and SMF4 manage PDU session 2.

[0099] Since SMFs belonging to the same SMF cluster and having a mutual primary / backup relationship have the same selection parameters, and the mapping relationship between SMF information and selection parameters is pre-established in NRF, each SMF in the same SMF cluster corresponds to the same selection parameter. In this step, the information of the second SMF obtained is the information of other SMFs in the SMF cluster where the first SMF is located.

[0100] The backup SMF discovery method provided in this disclosure, upon detecting a failure of the first SMF corresponding to the current session, sends an NF discovery request message carrying selection parameters for the first SMF to the NRF. The selection parameters include the identifier of the SMF group and service parameters, where the identifier of the SMF group is the identifier of the group to which the first SMF belongs. The method then receives an NF discovery response message from the NRF, obtains information about the second SMF carried therein, and determines a backup SMF based on the information of the second SMF. The information of the second SMF is determined by the NRF based on the mapping relationship between SMF information and the selection parameters, wherein the first SMF and the second SMF belong to the same SMF group. An SMF cluster is defined, in which SMFs within the same SMF cluster are mutually primary and backup, manage the same session, and are configured with the same selection parameters. This embodiment configures the same selection parameters for each SMF in the primary / backup relationship. These selection parameters include the SMF group identifier and service parameters. A mapping relationship between SMF information and selection parameters is pre-established. When an SMF fails, the backup SMF can be quickly identified based on this mapping relationship, without needing to first obtain information on all SMFs within the SMF group containing the failed SMF. This simplifies the backup SMF discovery process, improves system performance and backup SMF discovery efficiency, saves resources, and avoids network overload.

[0101] An SMF cluster must contain at least two SMFs to form a primary-backup relationship. When an SMF cluster contains three or more SMFs, in step 32, information about multiple second SMFs is obtained. These second SMFs are all SMFs that have a primary-backup relationship with the first SMF. Therefore, one of the multiple second SMFs is selected as the final backup SMF.

[0102] Accordingly, in some embodiments, determining the backup SMF based on the information of the second SMF (i.e., step 32) includes: in response to obtaining information of at least two second SMFs, randomly selecting information of one second SMF from the information of the second SMFs, and determining the backup SMF based on the information of the selected second SMF.

[0103] In some embodiments, before sending an NF discovery request message to the NRF (i.e., step 31), the method further includes the step of receiving selection parameters issued by a first SMF during the session establishment process.

[0104] The PDU session establishment process is as follows: The UE sends a PDU session establishment request message to the first SMF. The PDU session request message carries the combined parameters of S-NSSAI+DNN. After the first SMF sends the selection parameters of the first SMF to the UPF and PCF respectively, the first SMF returns a PDU session establishment response message to the UE.

[0105] In some embodiments, receiving the selection parameters sent by the first SMF includes the following steps: If the local NF is a UPF, receiving an N4 SessionEstablishment message carrying the selection parameters sent by the first SMF; if the local NF is a PCF, receiving a Session Management Policy Association Establishment message carrying the selection parameters sent by the first SMF. Specifically, the first SMF sends the N4 SessionEstablishment message to the UPF via the N4 interface to pass the selection parameters to the UPF, and the first SMF sends the Session Management Policy Association Establishment message to the PCF via the N7 interface to pass the selection parameters to the PCF.

[0106] In some embodiments, after determining the standby SMF based on the information of the second SMF, the standby SMF discovery method may further include the following steps: if the current NF is a UPF, sending an N4 Session Report Request message to the standby SMF; if the current NF is a PCF, sending a Session Management Policy Association Modification message to the standby SMF. By sending the above messages, the switchover between the primary and standby SMFs is completed.

[0107] In some embodiments, the service parameter is used to represent the service scope that the SMF can serve. For example, the service parameter can be an RSN, that is, the selection parameter is a combination parameter of the SMF group identifier and RSN.

[0108] In some embodiments, an SMF group includes at least two SMF clusters, and the SMFs belonging to different SMF clusters have different selection parameters. This is a scenario of redundant PDU sessions, where different SMF clusters manage one PDU session from the redundant PDU sessions. The selection parameters of each SMF in the same SMF cluster are the same, while the selection parameters for different SMF clusters are different, that is, the service parameters in the selection parameters are different (the SMF group identifiers are the same).

[0109] This disclosure also provides an alternative SMF discovery method, such as... Figure 5 As shown, the backup SMF discovery method includes the following steps:

[0110] Step 41: Send an NF registration request message to the NRF. The NF registration request message carries the selection parameters of this SMF so that the NRF can establish a mapping relationship between the information of this SMF and the selection parameters. The selection parameters include the identifier of the SMF group to which this SMF belongs and the service parameters. Here, this SMF belongs to an SMF cluster within the SMF group. The SMFs in the same SMF cluster are mutually primary and backup, manage the same session, and are configured with the same selection parameters.

[0111] In this step, the SMF registers itself by sending an NF registration request message to the NRF. The NF registration request message carries an NF profile, which includes the selection parameters of the SMF, namely the identifier of the SMF group to which the SMF belongs and the service parameters.

[0112] The backup SMF discovery method provided in this disclosure sends the SMF's selection parameters to the NRF when the SMF initiates registration with the NRF. This allows the NRF to establish a mapping relationship between the SMF information and the selection parameters locally. Subsequently, when other nodes initiate SMF discovery with the NRF, they can directly find all matching SMFs by carrying the selection parameters. This disclosure configures the same selection parameters for each SMF in a primary / backup relationship. These selection parameters include the SMF group identifier and service parameters, and a mapping relationship between SMF information and selection parameters is pre-established. When an SMF fails, the backup SMF can be quickly determined based on this mapping relationship, without needing to first obtain information on all SMFs in the SMF group containing the failed SMF. This simplifies the backup SMF discovery process, improves system performance and backup SMF discovery efficiency, saves resources, and avoids network overload.

[0113] In some embodiments, after sending an NF registration request message to the NRF (i.e., step 41), the alternative SMF discovery method may further include the following steps: receiving an NF registration response message returned by the NRF, the NF registration response message carrying an NF configuration file.

[0114] In some embodiments, the backup SMF discovery method further includes the following steps: during session establishment, in response to receiving a session establishment request message sent by the user equipment, sending selection parameters to the NF.

[0115] The PDU session establishment process is as follows: The UE sends a PDU session establishment request message to the first SMF. The PDU session request message carries the combined parameters of S-NSSAI+DNN. After the first SMF sends the selection parameters of the first SMF to the UPF and PCF respectively through different messages, the first SMF returns a PDU session establishment response message to the UE.

[0116] In some embodiments, sending the selection parameters to the NF (i.e., step 41) includes the following steps: when the NF is a UPF, sending an N4 SessionEstablishment message carrying the selection parameters to the UPF; when the NF is a PCF, sending a Session Management Policy Association Establishment message carrying the selection parameters to the PCF. Specifically, the SMF sends the N4 SessionEstablishment message to the UPF via the N4 interface to pass the selection parameters to the UPF, and the SMF sends the Session Management Policy Association Establishment message to the PCF via the N7 interface to pass the selection parameters to the PCF.

[0117] In some embodiments, the service parameter is used to represent the service scope that the SMF can serve. For example, the service parameter can be an RSN, that is, the selection parameter is a combination parameter of the SMF group identifier and RSN.

[0118] In some embodiments, an SMF group includes at least two SMF clusters, and the SMFs belonging to different SMF clusters have different selection parameters. This is a scenario of redundant PDU sessions, where different SMF clusters manage one PDU session from the redundant PDU sessions. The selection parameters of each SMF in the same SMF cluster are the same, while the selection parameters for different SMF clusters are different, that is, the service parameters in the selection parameters are different (the SMF group identifiers are the same).

[0119] To clearly describe the solution of the embodiments of this disclosure, the following detailed explanation of the process by which UPF1 detects an SMF1 fault and discovers a backup SMF is provided in conjunction with a specific example. Figure 6 The signaling flowchart of the backup SMF discovery method for UPF1 detecting SMF1 fault provided in the embodiments of this disclosure is as follows: Figure 6 As shown, the PDU session establishment process includes the following steps:

[0120] S1, the UE sends a PDU Session Establish Request message to SMF1, which carries the combined parameters of S-NSSAI+DNN.

[0121] S2, SMF1 sends an N4 Session Establishment message to UPF1, which carries selection parameters consisting of the SMF group identifier and RSN; SMF1 sends a Session Management Policy Association Establishment message to PCF, which carries selection parameters consisting of the SMF group identifier and RSN.

[0122] S3, SMF1 returns a PDU Session Establish Response message to the UE.

[0123] like Figure 6 As shown, UPF1 detected a fault in SMF1 and performed the following steps:

[0124] S4, UPF1 sends an NF Discovery Request message to the NRF, which carries selection parameters consisting of the SMF group identifier and RSN.

[0125] S5, NRF determines the SMF2 information corresponding to the selection parameter based on the mapping relationship between the SMF information and the selection parameter (SMF group identifier + RSN).

[0126] S6, NRF sends an NF Discovery Response message to UPF1, which carries information about SMF2.

[0127] S7, UPF1 sends an N4 Session Report Request message to SMF2 to complete the switchover between the primary and backup SMFs.

[0128] The following example illustrates in detail the process by which the PCF detects a fault in SMF1 and discovers a backup SMF. Figure 7 This is a signaling flowchart of a backup SMF discovery method for PCF detecting SMF1 faults provided in an embodiment of this disclosure. The PDU session establishment process is not described in detail here. Figure 7 As shown, the PCF detected a fault in SMF1 and performed the following steps:

[0129] S4', the PCF sends an NF Discovery Request message to the NRF, which carries selection parameters consisting of the SMF group identifier + RSN.

[0130] S5', NRF determines the SMF2 information corresponding to the selection parameter based on the mapping relationship between the SMF information and the selection parameter (SMF group identifier + RSN).

[0131] S6', NRF sends an NF Discovery Response message to PCF, which carries information about SMF2.

[0132] S7', PCF sends a Session Management Policy Association Modification message to SMF2 to complete the switchover between the primary and backup SMFs.

[0133] The following example will be used to explain in detail the process of SMF registering with NRF. Figure 8 This is a signaling flowchart for SMF registration with NRF. Figure 8 As shown, SMF registration with NRF includes the following steps:

[0134] S10, the SMF sends an NF Registration Request message to the NRF, which carries selection parameters consisting of the SMF group identifier and RSN.

[0135] S20, NRF establishes a mapping relationship between the selection parameters (SMF group identifier + RSN) and the SMF information.

[0136] S30, NRF returns an NF Registration Response message to SMF, which carries the NF configuration file.

[0137] This disclosure can be applied to vertical industry application scenarios such as industrial applications and control, remote manufacturing, remote surgery, and traffic safety and control. These scenarios require ultra-high reliability and ultra-high low latency. Therefore, 3GPP has specifically defined the uRLLC feature. In vertical industry scenarios, end-to-end session redundancy improves communication reliability. In this case, the UE uses independent DNN+S-NSSAI to establish two redundant PDU sessions, and the two PDU sessions are respectively connected to two independent SMFs. Simultaneously, multiple SMFs serving vertical industry services are located within the same SMF group.

[0138] When the embodiments of this disclosure are applied to vertical industry application scenarios (such as coal mines, power, industrial control, etc.), for different SMFs within an SM group, if they can serve uRLLC dual-redundant PDU sessions, then a service parameter is configured for them, referring to the current 3GPP specifications, namely, a combination parameter of the SMF group identifier + RSN. To ensure that the dual-redundant PDU sessions fall on two different SMFs, these two redundant PDU sessions correspond to two different RSN parameter values, and these two RSN parameter values ​​are configured on different SMFs respectively.

[0139] When an SMF within an SMF group fails, and other NFs (Network Functions) are reselecting an SMF for uRLLC sessions already established on the failed SMF, all SMFs supporting this RSN (Recurrent Service Number) can be directly selected from the SMF group containing the failed SMF. Then, one SMF can be chosen to replace the failed SMF. For an SMF carrying millions of redundant PDU sessions in a vertical industry, if the scheme of this disclosure is used to select a backup SMF after a failure, a backup SMF can be selected in one step for each PDU session, simplifying the process, improving system performance, saving core network resources, and avoiding overload.

[0140] Based on the same technical concept, this disclosure also provides a Network Data Warehouse Functional Entity (NRF), such as... Figure 9 As shown, it includes a receiving module 101, an acquisition module 102, a discovery module 103, and a sending module 104. The receiving module 101 is used to receive an NF discovery request message sent by a network function node NF. The NF discovery request message is sent by the NF when it detects a failure of the first session management function entity SMF corresponding to the current session.

[0141] The acquisition module 102 is used to acquire the selection parameters carried in the NF discovery request message. The selection parameters include the identifier of the SMF group and service parameters. The identifier of the SMF group is the identifier of the group to which the first SMF belongs.

[0142] The discovery module 103 is used to determine the information of the second SMF corresponding to the selection parameter based on the mapping relationship between the SMF information and the selection parameter, wherein the first SMF and the second SMF belong to the same SMF cluster of the same SMF group, the SMFs in the same SMF cluster are mutually primary and backup, manage the same session, and are configured with the same selection parameter.

[0143] The sending module 104 is used to send an NF discovery response message carrying information of the second SMF to the NF.

[0144] In some embodiments, such as Figure 10As shown, the network data warehouse functional entity may further include a creation module 105, and a receiving module 101 is further configured to receive an NF registration request message sent by the SMF.

[0145] The acquisition module 102 is also used to acquire the selection parameters carried in the NF registration request message.

[0146] The module 105 is used to establish a mapping relationship between the selection parameters and the information of the SMF.

[0147] In some embodiments, the service parameter is a redundant sequence number (RSN).

[0148] In some embodiments, an SMF group includes at least two SMF clusters, and the selection parameters of SMFs belonging to different SMF clusters are different.

[0149] This disclosure also provides a Network Functional Node (NF), such as Figure 11 As shown, it includes a sending module 201, a receiving module 202, and an acquisition module 203. The sending module 201 is used to send a Network Function Node (NF) discovery request message to the Network Data Warehouse Function Entity (NRF) in response to detecting a fault in the first Session Management Function Entity (SMF) corresponding to the current session. The NF discovery request message carries selection parameters for the first SMF, including the identifier of the SMF group and service parameters. The identifier of the SMF group is the identifier of the group to which the first SMF belongs.

[0150] The receiving module 202 is used to receive the NF discovery response message sent by the NRF.

[0151] The determination module 203 is used to obtain the information of the second SMF carried therein, and determine the backup SMF based on the information of the second SMF. The information of the second SMF is determined by the NRF based on the mapping relationship between the information of the SMF and the selection parameters and the selection parameters. The first SMF and the second SMF belong to the same SMF cluster of the same SMF group. The SMFs in the same SMF cluster are mutually primary and backup, manage the same session, and are configured with the same selection parameters.

[0152] In some embodiments, the determining module 203 is configured to, in response to obtaining information of at least two second SMFs, randomly select information of one second SMF from the information of the second SMFs, and determine a backup SMF based on the information of the selected second SMF.

[0153] In some embodiments, the receiving module 202 is further configured to receive the selection parameters sent by the first SMF during the session establishment process.

[0154] In some embodiments, the receiving module 202 is configured to, when the local network function node NF is a user plane function entity (UPF), receive an N4 session establishment message carrying the selection parameters sent by the first SMF; and when the local network function node NF is a policy control function entity (PCF), receive a session management policy association establishment message carrying the selection parameters sent by the first SMF.

[0155] In some embodiments, the service parameter is a redundant sequence number (RSN).

[0156] In some embodiments, an SMF group includes at least two SMF clusters, and the selection parameters of SMFs belonging to different SMF clusters are different.

[0157] This disclosure also provides a Session Management Function (SMF) entity, such as... Figure 12 As shown, it includes a registration module 301, which is used to send a Network Function Node (NF) registration request message to the Network Data Warehouse Functional Entity (NRF). The NF registration request message carries selection parameters for the current SMF, so that the NRF can establish a mapping relationship between the information of the current SMF and the selection parameters. The selection parameters include the identifier of the SMF group to which the current SMF belongs and service parameters. The current SMF belongs to an SMF cluster within the SMF group. The SMFs within the same SMF cluster are mutually primary and backup, manage the same session, and are configured with the same selection parameters.

[0158] In some embodiments, such as Figure 13 As shown, the session management function entity also includes a parameter distribution module 302, which is used to distribute the selection parameters to the network function node (NF) of the session in response to receiving a session establishment request message sent by the user equipment during the session establishment process.

[0159] In some embodiments, the parameter delivery module 302 is used to send an N4 session establishment message carrying the selection parameters to the UPF when the NF is a User Plane Function Entity (UPF); and to send a session management policy association establishment message carrying the selection parameters to the PCF when the NF is a Policy Control Function Entity (PCF).

[0160] In some embodiments, the service parameter is a redundant sequence number (RSN).

[0161] In some embodiments, an SMF group includes at least two SMF clusters, and the selection parameters of SMFs belonging to different SMF clusters are different.

[0162] This disclosure also provides an electronic device, which includes one or more processors and a storage device; wherein the storage device stores one or more programs, which, when executed by the one or more processors, cause the one or more processors to implement the alternative SMF discovery method provided in the foregoing embodiments.

[0163] This disclosure also provides a computer-readable medium having a computer program stored thereon, wherein the computer program, when executed, implements the alternative SMF discovery method as provided in the foregoing embodiments.

[0164] It will be understood by those skilled in the art that all or some of the steps in the methods disclosed above, and the functional modules / units in the apparatus, can be implemented as software, firmware, hardware, and suitable combinations thereof. In hardware implementations, the division between functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed collaboratively by several physical components. Some or all physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and can be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0165] Example embodiments have been disclosed herein, and while specific terminology has been used, it is for illustrative purposes only and should be construed as such, and is not intended to be limiting. In some instances, it will be apparent to those skilled in the art that features, characteristics, and / or elements described in conjunction with particular embodiments may be used alone, or in combination with features, characteristics, and / or elements described in conjunction with other embodiments, unless otherwise expressly indicated. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of the invention as set forth in the appended claims.

Claims

1. A backup SMF discovery method, characterized in that, The method includes: In response to receiving an NF discovery request message sent by a network function node (NF), the selection parameters carried therein are obtained. The NF discovery request message is sent by the NF when it detects a failure of the first session management function entity (SMF) corresponding to the current session. The selection parameters include the identifier of the SMF group and service parameters. The identifier of the SMF group is the identifier of the group to which the first SMF belongs. Based on the mapping relationship between the SMF information and the selection parameters, the information of the second SMF corresponding to the selection parameters is determined. The first SMF and the second SMF belong to the same SMF cluster of the same SMF group. The SMFs in the same SMF cluster are mutually primary and backup, manage the same session, and are configured with the same selection parameters. Send an NF discovery response message carrying information about the second SMF to the NF.

2. The method of claim 1, wherein, The method further includes: In response to receiving an NF registration request message from SMF, retrieve the selection parameters carried therein; Establish a mapping relationship between the selection parameters and the information of the SMF.

3. The method of claim 1, wherein, The service parameter is a redundant serial number (RSN).

4. The method according to any one of claims 1 to 3, characterized in that, An SMF group consists of at least two SMF clusters, and the selection parameters of SMFs belonging to different SMF clusters are different. 5.A method for backup SMF discovery, characterized in that, The method includes: In response to detecting a failure of the first session management function entity (SMF) corresponding to the current session, a network function node (NF) discovery request message is sent to the network data warehouse function entity (NRF). The NF discovery request message carries selection parameters for the first SMF, including the identifier of the SMF group and service parameters. The identifier of the SMF group is the identifier of the group to which the first SMF belongs. The system receives the NF discovery response message sent by the NRF, obtains the information of the second SMF carried therein, and determines the backup SMF based on the information of the second SMF. The information of the second SMF is determined by the NRF based on the mapping relationship between the information of the SMF and the selection parameters and the selection parameters. The first SMF and the second SMF belong to the same SMF cluster within the same SMF group. The SMFs within the same SMF cluster are mutually primary and backup, manage the same session, and are configured with the same selection parameters.

6. The method of claim 5, wherein, The step of determining the backup SMF based on the information of the second SMF includes: In response to obtaining information from at least two second SMFs, information from one second SMF is randomly selected from the information of the second SMFs, and a backup SMF is determined based on the selected second SMF information.

7. The method of claim 5, wherein, Before sending an NF discovery request message to the Network Data Warehouse Functional Entity (NRF), the method further includes: During the session establishment process, the selection parameters sent by the first SMF are received.

8. The method of claim 7, wherein, The step of receiving the selection parameters sent by the first SMF includes: When the Network Function Node (NF) is a User Plane Function Entity (UPF), it receives an N4 session establishment message carrying the selection parameters sent by the first SMF. When the network functional node (NF) is a policy control function entity (PCF), it receives a session management policy association establishment message carrying the selection parameters sent by the first SMF.

9. The method of claim 5, wherein, The service parameter is a redundant serial number (RSN).

10. The method according to any one of claims 5 to 9, wherein, An SMF group consists of at least two SMF clusters, and the selection parameters of SMFs belonging to different SMF clusters are different. 11.A backup SMF discovery method, characterized in that, The method includes: Send a Network Function Node (NF) registration request message to the Network Data Warehouse Functional Entity (NRF). The NF registration request message carries the selection parameters of this SMF, so that the NRF can establish a mapping relationship between the information of this SMF and the selection parameters. The selection parameters include the identifier of the SMF group to which this SMF belongs and service parameters. This SMF belongs to an SMF cluster within an SMF group. SMFs within the same SMF cluster are in a primary / backup relationship with each other, manage the same session, and are configured with the same selection parameters.

12. The method of claim 11, wherein, The method further includes: During the session establishment process, in response to receiving a session establishment request message from the user equipment, the selection parameters are sent to the network function node (NF) of the session.

13. The method as described in claim 12, characterized in that, Sending the selection parameters to the Network Function Node (NF) of the session includes: In the case that the NF is a User Plane Function Entity (UPF), an N4 session establishment message carrying the selection parameters is sent to the UPF. In the case that the NF is a Policy Control Function Entity (PCF), a Session Management Policy Association Establishment Message carrying the selection parameters is sent to the PCF.

14. The method as described in claim 11, characterized in that, The service parameter is a redundant serial number (RSN).

15. The method according to any one of claims 11 to 14, wherein, An SMF group consists of at least two SMF clusters, and the selection parameters of SMFs belonging to different SMF clusters are different.

16. A network data repository function entity, characterized by It includes a receiving module, an acquisition module, a discovery module, and a sending module. The receiving module is used to receive an NF discovery request message sent by a network function node (NF). The NF discovery request message is sent by the NF when it detects a failure of the first session management function entity (SMF) corresponding to the current session. The acquisition module is used to acquire the selection parameters carried in the NF discovery request message. The selection parameters include the identifier of the SMF group and service parameters. The identifier of the SMF group is the identifier of the group to which the first SMF belongs. The discovery module is used to determine the information of the second SMF corresponding to the selection parameter based on the mapping relationship between the SMF information and the selection parameter. The first SMF and the second SMF belong to the same SMF cluster of the same SMF group. The SMFs in the same SMF cluster are mutually primary and backup, manage the same session, and are configured with the same selection parameter. The sending module is used to send an NF discovery response message carrying information of the second SMF to the NF.

17. A network function node, the network function node comprising: The system includes a sending module, a receiving module, and a determining module. The sending module is used to send a Network Function Node (NF) discovery request message to the Network Data Warehouse Function Entity (NRF) in response to detecting a fault in the first Session Management Function Entity (SMF) corresponding to the current session. The NF discovery request message carries selection parameters for the first SMF, including the identifier of the SMF group and service parameters. The identifier of the SMF group is the identifier of the group to which the first SMF belongs. The receiving module is used to receive the NF discovery response message sent by the NRF; The determining module is used to obtain the information of the second SMF carried therein, and determine the backup SMF based on the information of the second SMF. The information of the second SMF is determined by the NRF based on the mapping relationship between the information of the SMF and the selection parameters and the selection parameters. The first SMF and the second SMF belong to the same SMF cluster of the same SMF group. The SMFs in the same SMF cluster are mutually primary and backup, manage the same session, and are configured with the same selection parameters.

18. A session management function entity, comprising: The system includes a registration module, which is used to send a Network Function Node (NF) registration request message to the Network Data Warehouse Functional Entity (NRF). The NF registration request message carries selection parameters for the current SMF, so that the NRF can establish a mapping relationship between the information of the current SMF and the selection parameters. The selection parameters include the identifier of the SMF group to which the current SMF belongs and service parameters. This SMF belongs to an SMF cluster within an SMF group. SMFs within the same SMF cluster are in a primary / backup relationship with each other, manage the same session, and are configured with the same selection parameters.

19. An electronic device comprising: One or more processors; A storage device on which one or more programs are stored; When the one or more programs are executed by the one or more processors, the one or more processors implement the alternative SMF discovery method as described in any one of claims 1-15.

20. A computer readable medium having stored thereon a computer program, wherein, When the program is executed, it implements the alternative SMF discovery method as described in any one of claims 1-15.

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