Methods, systems, and computer-readable media for distributing network function (NF) high availability (HA) topology information in a core network

Abstract

A method for distributing network function (NF) high availability (HA) topology information in a core network includes receiving, at a network repository function (NRF) comprising at least one processor, NFRegister requests from a plurality of producer NFs in a set of NFs including NF HA topology information of the producer NFs. The method further includes registering the producer NFs and storing the NF HA topology information of the producer NFs. The method further includes receiving, from a consumer NF or a service communication proxy (SCP), a NFDiscover request containing at least one service discovery parameter corresponding to a service provided by a producer NF. The method further includes responding to the NFDiscover request by generating a NFDiscover response, including the NF HA topology information of the producer NF in the NFDiscover response, and communicating the NFDiscover response to the consumer NF or the SCP.

Description

[0001] Priority Statement

[0002] This application claims priority to U.S. Patent Application Serial No. 17 / 334,268, filed May 28, 2021, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] This article describes topics related to providing high availability support for NF. More specifically, this article describes methods, systems, and computer-readable media for distributing NF HA topology information in the core network. Background Technology

[0004] In 5G telecommunications networks, network functions that provide services are referred to as producer NFs or NF service producers. Network functions that consume services are referred to as consumer NFs or NF service consumers. A network function can be a producer NF, a consumer NF, or both, depending on whether the network function is consuming, producing, or both consuming and producing services. The terms "producer NF" and "NF service producer" are used interchangeably herein. Similarly, the terms "consumer NF" and "NF service consumer" are used interchangeably herein.

[0005] A given producer NF may have many service endpoints, where a service endpoint is a contact point for one or more NF instances hosted by the producer NF. A service endpoint is identified by a combination of an Internet Protocol (IP) address and port number, or by a fully qualified domain name that resolves to the IP address and port number on the network node hosting the producer NF. An NF instance is an instance of the producer NF that provides a service. A given producer NF may include more than one NF instance. It should also be noted that multiple NF instances can share the same service endpoint.

[0006] Producer NFs register with the Network Functions Repository Function (NRF). The NRF maintains service profiles for available NF instances, which identify the services supported by each NF instance. The terms "service profile" and "NF profile" are used interchangeably in this document. Consumer NFs can subscribe to receive information about producer NF instances that have registered with the NRF.

[0007] Besides the consumer NF, another network node that can subscribe to receive information about NF service instances is the Service Communication Agent (SCP). The SCP subscribes to the NRF and obtains information about the reachability and service profile of the producer NF service instances. The consumer NF connects to the Service Communication Agent, which load balances traffic between the producer NF service instances providing the required services or routes traffic directly to the destination producer NF instance.

[0008] Besides SCP, another example of an intermediate proxy node that routes traffic between producer and consumer NFs is the Secure Edge Protection Proxy (SEPP). SEPP is a network node used to protect control plane traffic exchanged between different 5G Public Land Mobile Networks (PLMNs). Therefore, SEPP performs message filtering, policing, and topology hiding for all Application Programming Interface (API) messages transmitted between PLMNs.

[0009] One issue in 5G communication networks is that the 3GPP standard does not provide a method for NFs (Active Networks) to publish their HA (High Availability) topology information to other NFs in the 5G network. NFs in 5G networks support different HA topologies, including primary-primary, primary-backup, and N+K, where N is the number of active NF instances and K is the number of backup NF instances. Consumer NFs seeking services from producer NFs operating in an HA topology need to know the HA topology for load balancing and rerouting in case of a producer NF failing to provide services to the consumer NF. However, the 3GPP standard currently does not provide a method for producer NFs to publish their HA topology information to the core network. Therefore, load balancing and rerouting in the 5G core network may be performed suboptimally.

[0010] Given these and other difficulties, there is a need for methods, systems, and computer-readable media for distributing NF HA topology information in the core network. Summary of the Invention

[0011] A method for distributing Network Function (NF) High Availability (HA) topology information in a core network includes receiving, at an NF Repository Function (NRF) including at least one processor, an NFRegister request containing NF HA topology information of a producer NF from a plurality of producer NFs in an NF set. The method further includes registering the producer NFs and storing their NF HA topology information. The method also includes receiving, from a consumer NF or a Service Communication Agent (SCP), an NFDiscover request containing at least one service discovery parameter corresponding to a service provided by the producer NF. The method further includes responding to the NFDiscover request by generating an NFDiscover response, including the producer NF's NF HA topology information in the NFDiscover response, and transmitting the NFDiscover response to the consumer NF or SCP.

[0012] According to another aspect of the subject matter described herein, receiving an NFRegister request that includes NF HA topology information includes receiving an NFRegister request that includes information identifying the type of NF HA topology supported by the producer NF.

[0013] According to another aspect of the subject matter described herein, information identifying NF HA topology types includes information identifying one of the following: primary-primary NF HA topology type, primary-backup NF HA topology type, and N+K NF HA topology type, where N and K are integers that identify the number of primary NFs and the number of backup NFs in the NF set, respectively.

[0014] According to another aspect of the subject matter described herein, receiving an NFRegister request that includes NF HA topology information includes receiving NFRegister requests, each including information that identifies the current NF HA topology role of a producer NF in the NF set.

[0015] According to another aspect of the subject matter described in this article, the information identifying the current NF HA topology role of the producer NF in the NF set includes: information that identifies the producer NF as the primary NF or the standby NF.

[0016] According to another aspect of the subject matter described herein, responding to an NFDiscover request with an NFDiscover response that includes NF HA topology information includes information identifying the NF HA topology type and information identifying the current NF HA topology role in the NFDiscover response.

[0017] According to another aspect of the subject matter described herein, a method for distributing NF HA topology information includes receiving an NFUpdate request at an NRF from at least one of the producer NFs, including updated NF HA topology information of the at least one producer NF; and in response to receiving the NFUpdate request with updated NF HA topology information of the at least one producer NF, storing the updated NF HA topology information of the at least one producer NF and automatically transmitting the updated NF HA topology information to consumer NFs subscribed to receive updates of NF profile information of the at least one producer NF.

[0018] According to another aspect of the subject matter described herein, updated NF HA topology information indicates a change in the role of the first producer NF in the NF set from the primary HA role to the standby HA role and a change in the role of the second producer NF in the NF set from the standby HA role to the primary HA role, and wherein the method also includes transmitting a service request to the second producer NF at the consumer NF or SCP.

[0019] According to another aspect of the subject matter described herein, receiving an NFDiscover request from a consumer NF or SCP includes receiving an NFDiscover request from a consumer NF, and also includes using NF HA topology information at the consumer NF to select a producer NF in the NF set to provide services to the consumer NF.

[0020] According to another aspect of the subject matter described herein, receiving an NFDiscover request from a consumer NF or SCP includes receiving an NFDiscover request from an SCP, and also includes using NF HA topology information at the SCP to select a producer NF in the NF set to provide services to the consumer NF.

[0021] According to another aspect of the subject matter described herein, a system is provided for distributing Network Function (NF) High Availability (HA) topology information in a core network. The system includes a Network Function (NF) Repository Function (NRF) comprising at least one processor. The system also includes an NF Profile Manager implemented by at least one processor, configured to receive NFRegister requests including NF HA topology information of producer NFs from multiple producer NFs in an NF set, register producer NFs and store the NF HA topology information of producer NFs, receive NFDiscover requests containing at least one service discovery parameter corresponding to the service provided by the producer NF from a consumer NF or a Service Communication Agent (SCP), and respond to the NFDiscover requests by generating an NFDiscover response, including the NF HA topology information of the producer NFs in the NFDiscover response, and transmitting the NFDiscover response to the consumer NF or SCP.

[0022] According to another aspect of the subject matter described in this article, the NFRegister request includes information identifying the NFHA topology type supported by the producer NF.

[0023] According to another aspect of the subject matter described herein, information identifying NF HA topology types includes information identifying one of the following: primary-primary NF HA topology type, primary-backup NF HA topology type, and N+K NF HA topology type, where N and K are integers that identify the number of primary NFs and the number of backup NFs in the NF set, respectively.

[0024] According to another aspect of the subject matter described in this article, each NFRegister request includes information identifying the current NF HA topology role of the producer NF in the NF set.

[0025] According to another aspect of the subject matter described herein, information identifying the current NF HA topology role of a producer NF in an NF set includes information identifying the producer NF as a primary NF or a standby NF.

[0026] According to another aspect of the subject matter described herein, the NFDiscover response includes information identifying the NF HA topology type and information identifying the current NF HA topology role.

[0027] According to another aspect of the subject matter described herein, the NF profile manager is configured to receive an NFUpdate request from at least one of the producer NFs, including updated NF HA topology information of the at least one producer NF, and in response to receiving the NFUpdate request with updated NF HA topology information of the at least one producer NF, store the updated NF HA topology information of the at least one producer NF and automatically transmit the updated NF HA topology information to consumer NFs subscribed to receive updates of the NF profile information of the at least one producer NF.

[0028] According to another aspect of the subject matter described herein, updated NF HA topology information indicates a change in the role of the first producer NF in the NF set from the primary HA role to the standby HA role, and a change in the role of the second producer NF in the NF set from the standby HA role to the primary HA role.

[0029] According to another aspect of the topic described in this article, the NF profile manager receives NFDiscover requests from consumer NFs.

[0030] According to another aspect of the subject described in this article, the NF Profile Manager receives NFDiscover requests from SCP.

[0031] According to another aspect of the subject matter described herein, a non-transitory computer-readable medium having executable instructions stored thereon is provided, which, when executed by a computer's processor, control the computer to perform steps. The steps are performed at a Network Function (NF) Repository Function (NRF). The steps include receiving an NFRegister request from a plurality of producer NFs in an NF set, including NF high availability (HA) topology information of the producer NFs. The steps also include registering the producer NFs and storing the NF HA topology information of the producer NFs. The steps further include receiving an NFDiscover request from a consumer NF or a Service Communication Agent (SCP), containing at least one service discovery parameter corresponding to a service provided by the producer NF. The steps also include responding to the NFDiscover request by generating an NFDiscover response, including the NF HA topology information of the producer NFs in the NFDiscover response, and transmitting the NFDiscover response to the consumer NF or SCP.

[0032] The topics described herein can be implemented in software in conjunction with hardware and / or firmware. For example, the topics described herein can be implemented in software executed by a processor. In one exemplary implementation, the topics described herein can be implemented using a non-transitory computer-readable medium having computer-executable instructions stored thereon that control computer execution steps when executed by a computer's processor. Exemplary computer-readable media suitable for implementing the topics described herein include non-transitory computer-readable media such as disk storage devices, on-chip memory devices, programmable logic devices, and application-specific integrated circuits (ASICs). Furthermore, computer-readable media implementing the topics described herein can reside on a single device or computing platform or can be distributed across multiple devices or computing platforms. Attached Figure Description

[0033] An exemplary implementation of the subject matter described herein will now be explained with reference to the accompanying drawings, in which:

[0034] Figure 1 This is a network diagram illustrating an exemplary 5G network architecture;

[0035] Figure 2 This is a message flow diagram illustrating exemplary messages exchanged between network functions in a network that does not provide support for the distribution of NF HA topology information, where a consumer NF selects a producer NF that is currently in the standby HA role.

[0036] Figure 3 This is a message flow diagram illustrating exemplary messages exchanged between network functions in a network that does not provide support for the distribution of NF HA topology information, where a producer NF transitions to a standby HA role and a consumer NF attempts to obtain services from the producer NF after the HA state transition.

[0037] Figure 4 This is a message flow diagram illustrating an exemplary network that supports NF HA topology information distribution, where a producer NF provides the NRF with the HA topology type implemented by a set of NFs to which the producer NF is a member and the current HA role of the producer NF, and the NRF provides the consumer NF with HA topology information in the discovery response so that the consumer NF can use the HA topology information when selecting a producer NF to provide services.

[0038] Figure 5 This is a message flow diagram illustrating an exemplary network that supports HA topology information distribution, where the producer NF provides the NRF with the HA topology type implemented by the set of NFs to which the producer NF is a member and the current HA role of the producer NF. The NRF publishes the updated HA topology information to the consumer NF, and the consumer NF uses the updated HA topology information to select the primary producer NF to provide services.

[0039] Figure 6 This is a block diagram illustrating an exemplary architecture of an NRF that facilitates the distribution of NF HA topology information to consumer NFs and SCPs.

[0040] Figure 7 This is a flowchart illustrating an exemplary process performed by the NRF to distribute NF HA topology information to NF and SCP;

[0041] Figure 8 This is a block diagram illustrating an exemplary architecture of a consumer NF used to obtain and use NF HA topology information;

[0042] Figure 9 This is a flowchart illustrating an exemplary process performed by a consumer NF for obtaining and using NF HA topology information;

[0043] Figure 10 This is a block diagram illustrating an exemplary architecture of a producer NF used to distribute NF HA topology information; and

[0044] Figure 11 This is a flowchart illustrating an exemplary process performed by the producer NF for distributing NF HA topology information. Detailed Implementation

[0045] Figure 1 This is a block diagram illustrating an exemplary 5G system network architecture. Figure 1 The architecture includes NRF 100 and SCP 101, which can reside within the same Home Public Land Mobile Network (HPLMN). As described above, NRF 100 can maintain profiles of available producer NF service instances and their supported services, and allow consumer NFs or SCPs to subscribe to new / updated producer NF service instances and be notified of their registration. SCP 101 can also support service discovery and producer NF instance selection. SCP 101 can perform load balancing of connections between consumer and producer NFs.

[0046] NRF 100 is a repository of service profiles for NF or producer NF instances. To communicate with a producer NF instance, a consumer NF or SCP must obtain the producer NF instance's NF or service profile from NRF 100. The NF or service profile is a JavaScript Object Notation (JSON) data structure defined in 3GPP TS29.510. The NF or service profile definition includes at least one of a Fully Qualified Domain Name (FQDN), an Internet Protocol (IP) version 4 (IPv4) address, or an IP version 6 (IPv6) address.

[0047] exist Figure 1In this context, any network function can be a consumer NF, a producer NF, or both, depending on whether it is requesting, providing, or requesting and providing services. In the example shown, the NF includes a policy control function (PCF) 102 that performs policy-related operations in the network, a unified data management (UDM) function 104 that manages user data, and an application function (AF) 106 that provides application services.

[0048] Figure 1 The illustrated NF also includes a Session Management Function (SMF) 108 that manages the session between Access and Mobility Management Function (AMF) 110 and PCF 102. AMF 110 performs mobility management operations similar to those performed by the Mobility Management Entity (MME) in a 4G network. Authentication Server Function (AUSF) 112 performs authentication services for user equipment (UEs) seeking network access (such as UE 114).

[0049] The Network Slice Selection Function (NSSF) 116 provides network slicing services for devices seeking access to specific network capabilities and characteristics associated with a network slice. The Network Open Function (NEF) 118 provides an application programming interface (API) for application functions seeking information about Internet of Things (IoT) devices and other UEs attached to the network. NEF 118 performs functions similar to the Service Capability Open Function (SCEF) in 4G networks.

[0050] Radio Access Network (RAN) 120 connects User Equipment (UE) 114 to the network via a radio link. RAN 120 can utilize gNode B (gNB)... Figure 1 Access can be obtained through a wireless access point (not shown in the image) or other wireless access points. The User Plane Function (UPF) 122 can support various proxy functions for user plane services. An example of such a proxy function is the Multipath Transmission Control Protocol (MPTCP) proxy function. The UPF 122 can also support performance measurement functions, which can be used by the UE 114 to obtain network performance measurements. Figure 1 The diagram also shows a data network (DN) 124 through which the UE accesses data network services, such as Internet services.

[0051] SEPP 126 filters incoming traffic from another PLMN and performs topology hiding for traffic leaving the home PLMN. SEPP 126 can communicate with the SEPP in the external PLMN that manages the security of the external PLMN. Therefore, traffic between NFs in different PLMNs may pass through two SEPP functions, one for the home PLMN and the other for the external PLMN.

[0052] As mentioned above, one issue in 5G networks is the lack of a mechanism for defining NFs to distribute their HA topology information. For example, different NFs in a 5G core (5GC) network can implement different HA topology types. Examples of such HA topology types include:

[0053] Master-Master-In which multiple NFs in the NF set are simultaneously operable and provide services;

[0054] Primary-backup – some of these NFs are operational and provide services, while others are operational but not provide services unless one of the primary NFs fails or otherwise becomes unavailable; and

[0055] The N+K model – where N NFs are operational and provide services, and K NFs are operational but do not provide services unless one of the N primary NFs fails or otherwise becomes unavailable.

[0056] For NF consumers / SCPs, understanding the HA topology of NF producers is crucial for (re)routing and load balancing of 5G SBI traffic. 3GPP does not provide a method for disseminating HA-related information within the network. 3GPP implies a primary-primary HA topology for NF sets, but this is not the case for all deployments. An NF set is a logical group of NFs that provide the same service, support the same network slice, and are identified by the same NF set ID. 3GPP assumes that all NFs in an NF set are primary, but this may not be accurate, for example, if an operator decides to deploy some NFs in an NF set as primary and others as backup.

[0057] This article describes a method for publishing HA topology information for NFs, enabling consumer NFs or SCPs to use this information when selecting NFs to provide services. NF HA topology information can define the NFHA type implemented by the NF set, and the role of the published NF within that NF HA type. Without this solution, 5G SBI routing is impossible for HA topologies other than master-master topologies. As a workaround, NFs implementing N+K HA need to be deployed in master-master topologies, where network operators will face the following challenges:

[0058] In the event of a HA state transition (to standby) after resource creation, NF consumers / SCPs will have to face additional routing attempts; and

[0059] Consumer NF / SCPs will have issues when load balancing traffic between NF instances with different HA roles.

[0060] If a consumer NF or SCP sends an SBI request to a producer NF operating in a standby role, more routing attempts will be required because the standby NF will not expect to receive traffic, and such traffic will have to be rerouted by the consumer NF or SCP to another NF operating in an active role. Load balancing will be difficult if the consumer NF or SCP is unaware of the producer NF's HA role, as the standby NF should not be receiving live traffic.

[0061] Figure 2 This is a message flow diagram illustrating exemplary messages exchanged when a consumer NF or SCP attempts to route traffic to a standby producer NF in an NF set implementing an N+K HA topology. Figure 2 In this setup, producer NF-1 200 operates as the primary HA (High Availability) provider, and producer NF-2 202 operates as the standby HA provider. Producers NF-1 200 and NF-2 202 form NF set 204. NF set 204 implements an N+K HA topology.

[0062] refer to Figure 2 In the message flow, in step 1, the producer NF-1 200 sends an NFRegister request to the NRF 100. The NFRegister request contains the NF profile of the producer NF-1 200. However, 3GPP does not define how the producer NF-1 200 communicates to the NRF 100 the HA topology type implemented by NF set 204 or the role of the producer NF-1 200 in the HA topology type.

[0063] In step 2 of the message flow graph, producer NF-2 202, operating in a standby HA role, sends an NFRegister Request message to NRF 100. The NFRegister Request message does not include an indication that producer NF-2 202 is operating in a standby role. As a result, the consumer NF cannot know the NF HA topology type implemented by NF set 204 or the role of the producer NF in the NF set.

[0064] In step 3 of the message flow diagram, consumer NF or SCP 206 sends an NFDiscover request message to NRF 100. The NFDiscover request message may include discovery parameters for selecting the producer NF to provide the service. In step 4 of the message flow diagram, NRF 100 responds to the NFDiscover request message with an NFDiscover response message that includes the NF profiles of producer NF-1 200 and producer NF-2 202. However, the NFDiscover response message does not include the NF HA type implemented by NF set 204 or the HA roles of producer NF-1 200 and producer NF-2 202. As a result, consumer NF or SCP 206 may route a Service-Based Interface (SBI) service request to the producer NF operating in an alternate role, as shown in step 5 of the message flow diagram. When producer NF-2 202 receives the SBI service request message, it will reject the SBI service request message because it is operating in an alternate role. As a result, the consumer NF or SCP 206 needs to reroute the service request by selecting another NF and sending the SBI service request to another producer NF. The consumer NF or SCP 206 may need to reroute the service request multiple times until the request is received by a producer NF operating in an active HA role. Such rerouting is time-consuming and wastes network resources.

[0065] Figure 3 The diagram illustrates another potential problem that may occur when an NF HA state transition takes place. Figure 3 In this context, it is assumed that producer NF-1 200 and producer NF-2 202 have registered with NRF 100 without specifying the NF HA topology role and its NF HA topology type implemented by an NF set whose members are producer NF-1 200 or producer NF-2 202. Figure 3 In step 1 of the message flow diagram, consumer NF or SCP 206 sends an SBI service request to producer NF-1 200. Because producer NF-1 200 is operating in an active HA role, producer NF-1 200 responds to the SBI service request in step 2 with a 201Created message.

[0066] In step 3, an HA state transition occurs in NF set 204, where producer NF-1200 transitions to a standby HA role, and producer NF-2202 transitions to a primary HA role. In step 4 of the message flow graph, consumer NF or SCP 206 sends a follow-up service request to producer NF-1200, which is currently operating in a standby HA role. Because producer NF-1200 is operating in a standby role, it rejects the service request. As a result, consumer NF or SCP 206 will need to reroute the service request to another NF, leading to routing and network inefficiencies.

[0067] In order to solve Figure 2 and Figure 3 The difficulties illustrated by the message flow in this paper include the ability of a producer NF to communicate to the NRF the NF HA topology type implemented by the set of NFs to which the producer NF is a member, and the current HA role of the producer NF within that HA topology type. The NRF stores information indicating the NF HA topology type and the current NF HA role in an NF profile database or a separate database. When a consumer NF seeks to discover one or more producer NFs for providing services, the NRF includes information indicating the producer NF's NF HA topology role and NF HA topology type in its discovery response. The NF service consumer can then use the NF HA topology type and information to select the producer NF to provide the service.

[0068] Figure 4 This is a message flow diagram illustrating an exemplary network supporting NF HA topology information distribution. A producer NF provides the NRF with the HA topology type implemented by a set of NFs to which the producer NF is a member, as well as the producer NF's current HA role. The NRF then provides the HA topology information to a consumer NF in its discovery response, enabling the consumer NF to use this information to select a producer NF to provide services. (Reference) Figure 4In the message flow diagram, in step 1, producer NF-1 200 sends an NFRegister request message to NRF 100 to register producer NF-1 200 to provide services. The NFRegister request message indicates the NF HA topology type (which is primary / standby in the example shown) and the HF HA role (which is primary for producer NF-2 202). In step 3 of the message flow diagram, consumer NF or SCP 206 sends an NFDiscover request message to NRF 100. The NFDiscover request message may include discovery parameters for selecting a producer NF to provide services to a consumer NF. In step 4 of the message flow diagram, NRF 100 responds to the NFDiscover request message with an NFDiscover response message that includes the NF profiles of producer NF-1 200 and producer NF-2 202. The NFDiscover response message includes NFHA topology information indicating the NF HA type implemented by NF set 204 and the HA roles of producer NF-1 200 and producer NF-2 202. In the example shown, the NF HA topology information indicates that the NF HA topology type implemented by NF set 204 is primary / standby, the current NF HA role implemented by producer NF-1 200 is primary, and the current NF HA role implemented by producer NF-2 202 is standby.

[0069] Using NF HA topology information, consumer NF or SCP 206 selects the producer NF currently in the primary HA role to provide service. In the example shown, consumer NF or SCP 206 selects producer NF-1 200 to provide service. In step 5 of the message flow diagram, producer NF or SCP 206 sends an SBI service request to producer NF-1 200, which is operating in the active HA role. Because producer NF-1 200 is operating in the active HA role, producer NF-1 200 accepts the SBI service request and responds to the SBI service request with a 201Created message in step 6. Therefore, Figure 4 The diagram illustrates a scenario where NF HA topology information is provided to NRF 100 in the NFRegister message, distributed to the consumer NF or SCP in the NFDiscover response message, and used by the consumer NF or SCP to select the primary NF to handle the initial SBI service request message. Because the consumer NF or SCP possesses NF HA topology information, consumer NF or SCP 206 can avoid... Figure 2 The route shown is inefficient.

[0070] Figure 5This is an example message diagram illustrating the exchange of updated NF HA topology information in response to HA state transitions, and the message flow diagram using the updated HA topology information to select a new primary NF to provide service. (Reference) Figure 5 In step 1, an NF HA state transition occurs. This transition occurs when producer NF-1 200 switches its HA role from primary to standby, and producer NF-2 202 switches its HA role from standby to primary. In step 2 of the message flow diagram, producer NF-1 200 sends an NFUpdate request to NRF 100, identifying the new HA role of producer NF-1 200.

[0071] In step 3 of the message flow graph, in response to receiving an NFUpdate request, NRF 100 publishes a notification message to all consumer NFs or SCPs that have subscribed to receive updates regarding changes in the state of producer NF-1 200. In the example shown, producer NF-1 200 sends a notification message to consumer NF or SCP 206. The notification message includes updated NF HA topology information for producer NF-1 200.

[0072] In step 4 of the message flow diagram, producer NF-2 202 sends an NFUpdate request to NRF 100 containing the new NF HA role for producer NF-2 202. In the example shown, the NF Update message indicates that producer NF-2 202 is switching to the primary role. In step 5 of the message flow diagram, NRF 100 sends a notification message with the updated NF HA topology information for producer NF-2 202 to consumer NF or SCP 206.

[0073] In step 6 of the message flow diagram, consumer NF or SCP 206 formulates a follow-up SBI service request message, and consumer NF or SCP 206 sends the follow-up SBI service request to producer NF-2 202 based on the currently updated HF HA topology information, instead of sending the follow-up SBI service request message to producer NF-1 200. Figure 5 In the example shown, it is assumed that when producer NF-2 202 switches to the primary state, producer NF-2 202 has obtained the necessary status information to process subsequent SBI service requests from consumer NF or SCP 206. In step 7 of the message flow diagram, producer NF-2 202 sends a 200 OK message to consumer NF or SCP 206.

[0074] therefore, Figure 5The diagram illustrates a scenario where a producer NF automatically updates its HA role and communicates its new HA role to the NRF100, and where the NRF100 automatically distributes indications of the state change to consumer NFs and SCPs that have subscribed to receive updates regarding the state change of the NF. By using updated NF HA topology information, the subject matter described herein avoids... Figure 3 The scenario shown occurs where the NF HA state transition takes place and the subsequent SBI service request falls on the standby producer NF. Therefore, Figure 5 The scene shown is more Figure 3 The scenario shown provides increased efficiency, in Figure 3 In this process, the consumer NF or SCP needs to reroute the service request to another producer NF.

[0075] Figure 6 This is a block diagram illustrating an exemplary architecture of the NRF 100 capable of acquiring, storing, and distributing producer NF HA topology information. (Reference) Figure 6 The NRF 100 includes at least one processor 600 and memory 602. The NRF 100 also includes an NF profile database 604 that stores NF profiles of producer NFs registered with the NRF 100. The NRF 100 also includes an NF profile manager 606 that receives NFRegister request messages, stores NF profiles of producer NFs in database 604, and distributes NF profile information from consumer NFs. The NF profile manager 606 can also receive NFHA topology information from producer NFs and store the HF HA topology information in the NF profile database 604 or in a separate database maintained by the NRF 100. The NF profile manager 606 can provide NF HA topology information to consumer NFs or SCPs in response to NFDiscover requests and also in response to NFUpdate messages from producer NFs. The NF profile manager 606 can be implemented using computer-executable instructions stored in memory 602 and executed by processor 600.

[0076] Figure 7 This is a flowchart illustrating an exemplary method for distributing NF HA information. Figure 7 The steps in this process are performed at the NRF (such as NRF 100). See reference. Figure 7In step 700, the process includes receiving an NFRegister request from multiple producer NFs in the NF set, including NF HA topology information for the producer NFs. For example, NRF 100 may receive an NFRegister request from a producer NF, wherein the NFRegister request includes information identifying the NF HA topology type implemented by the producer NF and the current NF HA topology role implemented by each producer NF in the NF set. As described above, the NF HA topology type may include primary-primary, primary-standby, and N+K, where N and K are integers that identify the number of primary and standby NFs in the NF set, respectively. The NF HA topology role information provided in the NFRegister request can identify each NF as primary or standby.

[0077] In step 702, the process includes registering the producer NF and storing the NF HA topology information of the producer NF. For example, NRF 100 can register the producer NF by storing the producer NF's NF profile in NF profile database 604 and storing the registration status or status indicator of the NF indicating the REGISTERED status or condition. NRF 100 can store the NF HA topology information in NF profile database 604 or in a separate database used for storing NF HA topology information.

[0078] In step 704, the process includes receiving an NFDiscover request from a consumer NF or service communication agent (SCP) containing at least one service discovery parameter corresponding to a service provided by a producer NF. For example, NRF 100 may receive an NFDiscover request from a consumer NF, the request including parameters identifying that NF discovery is targeting the type of service for which it is requested.

[0079] In step 706, the process includes responding to an NFDiscover request by generating an NFDiscover response, which includes NF HA topology information for the producer NF, and sending the NFDiscover response to a consumer NF or SCP. For example, the NRF 100 may generate an NFDiscover response message in response to a received NFDiscover request message. The NFDiscover response message may include the NF profile of the producer NF that matches the service identifier parameter in the NFDiscover request. For each NF with available NF HA topology information, the NFDiscover response may also include the NF HA type implemented by the set of producer NFs and the current NF HA role of each producer NF. It should be noted that the NF HA topology information may be included as one or more attributes of the NF profile of each producer NF, or it may be communicated separately from the NF profile of the producer NF.

[0080] In step 708, the process includes receiving updated NF HA topology information for the producer NF. For example, when the NF HA topology role of the producer NF changes, the NRF 100 can receive an NFUpdate request message from the producer NF. Examples of NF HA topology role changes include changing from primary to standby or from standby to primary.

[0081] In step 710, the process includes publishing updated NF HA topology information of the producer NF to subscribers who wish to receive NFUpdates (NF updates) for the producer NF. For example, in response to receiving an NFUpdate request message for the producer NF, NRF 100 can update the producer NF's profile in the NF profile database. Additionally, if the producer NF's NF HA role changes, NRF 100 can also update the producer NF's NF HA role. NRF 100 can then send notifications of the changes to the NF profile and NF HA topology information to the consumer NFs and SCPs that are subscribed to receive the updates.

[0082] Figure 8 This is a block diagram illustrating an exemplary architecture for a consumer NF or SCP 206 that obtains and uses NF HA topology information to route SBI service requests. (Reference) Figure 8The consumer NF or SCP 206 includes at least one processor 800 and memory 802. The consumer NF or SCP 206 also includes an NF discovery / SBI request generator 804, which generates and sends an NFDiscover request to NRF 100, receives an NFDiscover response from NRF 100, wherein the NFDiscover response includes NF HA topology information, and generates and sends an SBI request to the producer NF selected using the NF HA topology information. The NF discovery / SBI request generator 804 can be implemented using computer-executable instructions stored in memory 802 and executed by processor 800.

[0083] Figure 9 This is a flowchart illustrating an exemplary process implemented by a consumer NF or SCP for obtaining and using NF HA topology information to select a producer NF to provide services. Figure 9 The steps shown can be performed by Figure 8 This is implemented using the consumer NF or SCP 206 shown. (See reference) Figure 9 In step 900, the process includes generating an NFDiscover request and sending the NFDiscover request to the NRF. For example, a consumer NF or SCP 206 may generate an NFDiscover request that includes discovery parameters for the services required by the consumer NF and send the NFDiscover request to NRF 100.

[0084] In step 902, the process includes receiving an NFDiscover response in response to an NFDiscover request. The NFDiscover response includes an NF profile that matches the discovery parameters from the request and NF HA topology information for the producer NF. The NF HA topology information may be included in the NF profile or may be included in a separate data structure.

[0085] In step 904, the process includes selecting a producer NF to provide service using NF HA topology information. For example, a consumer NF of SCP 206 can use NF HA topology information to select a primary NF to provide service to the consumer NF. In step 906, the process includes sending a new SBI request to the producer NF. For example, the consumer NF or SCP 206 can send an SBI request to the producer NF selected using NF HA topology information.

[0086] In step 908, the process includes receiving an NFUpdate request message containing updated NF HA topology information for the producer NF. For example, a consumer NF of SCP 206 can receive an NFUpdate request message containing updated HF HA topology information for the producer NF currently serving the consumer NF. The updated NF HA topology information can indicate that the role of the producer NF has changed.

[0087] In step 910, the process includes selecting a new producer NF to provide service based on the updated HF HA topology information. For example, when the role of the currently providing service producer NF changes to standby, the consumer NF or SCP 206 can select a new primary producer NF to provide service. In step 912, the consumer NF or SCP 206 generates and sends a new SBI request to the new producer NF. For example, the consumer NF or SCP 206 can generate and send an SBI request to the currently primary producer NF.

[0088] Figure 10 This is a block diagram illustrating an exemplary producer NF 200 or 202 capable of distributing NF HA topology information to other NFs. (Reference) Figure 10 The producer NF 200 or 202 includes at least one processor 1000 and a memory 1002. The producer NF 200 or 202 also includes an NF HA topology manager 1004, which maintains in the memory 1002 indications of the NF HA topology type and NF HA topology role implemented by the producer NF 200 or 202. The NF HA topology manager 1004 can also determine, for example, when the NF HA topology role of the producer NF 200 or 202 needs to be changed based on input from the network operator indicating that the NF HA topology of the producer NF 200 or 202 needs to be changed. The producer NF 200 or 202 also distributes its NF HA topology information to other NFs by sending NFRegister and NFUpdate messages to the NRF 100. The NF HA topology manager 1004 can be implemented using computer-executable instructions stored in the memory 1002 and executed by the processor 1000.

[0089] Figure 11 The diagram illustrates an exemplary process implemented by a producer NF when distributing its NF HA topology information to other NFs. (Reference) Figure 11 In step 1100, the process includes storing an indication of the HA topology type and HA topology role in memory. For example, producer NF 200 or 202 may store an indication of the current HA topology type and HA topology role implemented by producer NF 200 or 202 in memory 1002.

[0090] In step 1102, the process includes conveying NF HA topology information to the NRF. For example, producer NF 200 or 202 can generate and send an NFRegister request including NF HA topology information to NRF 100.

[0091] In step 1104, the process includes detecting the need for a change in the NF HA role. For example, producer NF 200 or 202 may determine that its NF HA topology role needs to be changed in response to receiving a notification from the network operator that a change is required.

[0092] In step 1106, producer NF 200 or 202 changes its NF HA role. For example, producer NF 200 or 202 may change from primary to standby or from standby to primary. In step 1108, producer NF 200 or 202 communicates the updated NF HA role to the NRF. For example, producer NF 200 or 202 may generate and send an NFUpdate request message with the updated NF HA role to NRF 100.

[0093] The benefits of the topics described in this article include the synergy between NRF and SCP in the indirect communication model. Another benefit is that this topic enables NF to open its supported HA topologies in 5GC, resulting in better (re)routing and load balancing at NF consumers / SCPs. The topics described in this article also provide better routing resilience for producers supporting master-slave or N+K HA topologies. Furthermore, the topics described in this article provide better routing resilience for networks with hybrid NF deployments (virtual machines (VMs), hardware, cloud-native) with different HA topologies.

[0094] The publication of each of the following references is incorporated herein by reference in its entirety.

[0095] References

[0096] 1. Third Generation Partner Program; Technical Specification Group Services and Systems; System Architecture of 5G System (5GS); Phase 2 (Release 17) 3GPP TS 23.501 V17.0.0 (2021-03).

[0097] 2. Third Generation Partner Program; Technical Specification Group Core Networks and Terminals; 5G Systems; Network Functions Repository Services; Phase 3 (Release 17) 3GPP TS 29.510 V17.1.0 (2021-03).

[0098] It should be understood that various details of the subject matter described herein may be altered without departing from the scope of the subject matter described herein. Furthermore, the foregoing description is for illustrative purposes only and not for limiting purposes, as the subject matter described herein is defined by the claims set forth below.

Claims

1. A method for distributing Network Function (NF) High Availability (HA) topology information in a core network, the method comprising: At the Network Function (NF) repository function (NRF) that includes at least one processor: Receive an NFRegister request message from multiple producer NFs in the NF set, including NF HA topology information of the producer NFs, wherein the NF HA topology information includes information identifying the current NF HA topology role of each producer NF in the NF set, wherein the information identifying the current NF HA topology role of the producer NF identifies the producer NF as a primary producer NF or a backup producer NF. Register the producer NF and store the NF HA topology information of the producer NF; Receive an NFDiscover request message from the consumer NF or service communication agent (SCP) containing at least one service discovery parameter corresponding to the service provided by the producer NF; as well as The NFDiscover request message is responded to by generating an NFDiscover response message, including the NF HA topology information of the producer NF in the NFDiscover response message, and transmitting the NFDiscover response message to the consumer NF or SCP. and At the consumer NF or SCP, the NFDiscover response message is received, and the information identifying each producer NF in the producer NF as a primary producer NF or a backup producer NF is used to select one of the producer NFs in the NF set that is identified as a primary producer NF and to avoid selecting a producer NF in the NF set that is a backup producer NF.

2. The method of claim 1, wherein receiving the NFRegister request message including the NF HA topology information comprises: Receive the NFRegister request message, which includes information identifying the NF HA topology type supported by the producer NF.

3. The method of claim 2, wherein the information identifying the NF HA topology type includes information identifying one of the following: primary-primary NF HA topology type, primary-backup NF HA topology type, and N+K NF HA topology type, wherein N and K are integers identifying the number of primary NFs and the number of backup NFs in the NF set, respectively.

4. The method of claim 2 or 3, wherein responding to the NFDiscover request message with the NFDiscover response message including the NF HA topology information comprises: The information identifying the NF HA topology type is included in the NFDiscover response message.

5. The method according to any one of claims 1 to 3, comprising: At the NRF, an NFUpdate request message including updated NF HA topology information of at least one of the producer NFs is received from the producer NFs. In response to receiving the NFUpdate request message with the updated NF HA topology information of the at least one producer NF, the updated NF HA topology information of the at least one producer NF is stored and the updated NF HA topology information is automatically transmitted to consumer NFs that have subscribed to receive updates to the NF profile information of the at least one producer NF.

6. The method of claim 5, wherein the updated NF HA topology information indicates a change in the role of a first producer NF in the NF set from a primary HA role to a standby HA role and a change in the role of a second producer NF in the NF set from a standby HA role to a primary HA role, and wherein the method further includes transmitting a service request to the second producer NF at the consumer NF or SCP.

7. The method of any one of claims 1 to 3, wherein receiving the NFDiscover request message from the consumer NF or SCP includes receiving the NFDiscover request message from the consumer NF.

8. The method of any one of claims 1 to 3, wherein receiving the NFDiscover request message from the consumer NF or SCP includes receiving the NFDiscover request message from the SCP.

9. A system for distributing Network Function (NF) High Availability (HA) topology information in a core network, the system comprising: Includes at least one processor's network function (NF) repository function (NRF); An NF profile manager, implemented by the at least one processor, is configured to receive an NFRegister request message from a plurality of producer NFs in an NF set, the NF HA topology information including information identifying the current NF HA topology role of each producer NF in the NF set, wherein the information identifying the current NF HA topology role identifies the producer NF as a primary producer NF or a backup producer NF; register the producer NFs and store the NF HA topology information of the producer NFs; receive an NFDiscover request message containing at least one service discovery parameter corresponding to the service provided by the producer NFs; and respond to the NFDiscover request message by generating an NFDiscover response message, including the NF HA topology information of the producer NFs in the NFDiscover response message, and transmitting the NFDiscover response message. as well as A consumer NF or service communication agent (SCP) is used to receive the NFDiscover response message and to select a producer NF in the NF set that is identified as a primary producer NF or a backup producer NF using the information that identifies each producer NF in the producer NF as a primary producer NF and to avoid selecting a producer NF in the NF set that is a backup producer NF.

10. The system of claim 9, wherein the NFRegister request message includes information identifying the NF HA topology type supported by the producer NF.

11. The system of claim 10, wherein the information identifying the NF HA topology type includes information identifying one of the following: primary-primary NF HA topology type, primary-backup NF HA topology type, and N+K NF HA topology type, wherein N and K are integers identifying the number of primary NFs and the number of backup NFs in the NF set, respectively.

12. The system of claim 10 or 11, wherein the NFDiscover response message includes the information identifying the NF HA topology type.

13. The system of any one of claims 9 to 11, wherein the NF profile manager is configured to receive an NFUpdate request message including updated NF HA topology information of the at least one producer NF from at least one of the producer NFs, and in response to receiving the NFUpdate request message having the updated NF HA topology information of the at least one producer NF, store the updated NF HA topology information of the at least one producer NF and automatically transmit the updated NF HA topology information to consumer NFs subscribed to receive updates of NF profile information of the at least one producer NF.

14. The system of claim 13, wherein the updated NF HA topology information indicates a change in the role of a first producer NF in the NF set from a primary HA role to a standby HA role and a change in the role of a second producer NF in the NF set from a standby HA role to a primary HA role.

15. The system of any one of claims 9 to 11, wherein the NF profile manager receives the NFDiscover request message from the consumer NF.

16. The system of any one of claims 9 to 11, wherein the NF profile manager receives the NFDiscover request message from the SCP.

17. A non-transitory computer-readable medium having executable instructions stored thereon, the executable instructions controlling the computer to perform steps when executed by a processor of a computer, including: At the Network Functions (NF) repository function (NRF): Receive an NFRegister request message from multiple producer NFs in the NF set, including NF high availability (HA) topology information of the producer NFs, wherein the NF HA topology information includes information identifying the current NF HA topology role of each producer NF in the NF set, wherein the information identifying the current NF HA topology role of the producer NF identifies the producer NF as a primary producer NF or a standby producer NF. Register the producer NF and store the NF HA topology information of the producer NF; Receive an NFDiscover request message from the consumer NF or service communication agent (SCP) containing at least one service discovery parameter corresponding to the service provided by the producer NF; as well as The NFDiscover request message is responded to by generating an NFDiscover response message, including the NF HA topology information of the producer NF in the NFDiscover response message, and transmitting the NFDiscover response message to the consumer NF or SCP. and At the consumer NF or SCP, the NFDiscover response message is received, and the information identifying each producer NF in the producer NF as a primary producer NF or a backup producer NF is used to select one of the producer NFs in the NF set that is identified as a primary producer NF and to avoid selecting a producer NF in the NF set that is a backup producer NF.

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