WO2020200488A1

WO2020200488A1 - Service operation execution

Info

Publication number: WO2020200488A1
Application number: PCT/EP2019/064124
Authority: WO
Inventors: Maria Cruz BARTOLOMÉ RODRIGO; Attila MIHÁLY
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2019-04-01
Filing date: 2019-05-29
Publication date: 2020-10-08
Also published as: EP3949340A1

Abstract

There is provided method of operating a first network function, NF, node for execution of a service operation. The first NF node is a provider of a first service. The method comprises, in response to a request from a second service of a second NF node for execution of a service operation of the first service, initiating (100) a transfer of context data to a third NF node with a transfer of the service operation of the first service to the third NF node. The context data comprises data required for the service operation of the first service to be executed.

Description

SERVICE OPERATION EXECUTION

Technical Field

The present idea relates to network function nodes and methods of operating the network function nodes for execution of a service operation.

Background

The architecture of the next generation (i.e. the fifth generation, 5G) of networks is defined in 3GPP TS 23.501 V15.4.0 and 3GPP TS 23.502 V15.4.1 . A way in which these networks differ is that the Core Network (CN) architecture is mostly built around a Service Based Architecture (SBA) paradigm. That is, the networks comprise a network domain, which is basically the CN, in which different functional components are defined as services. These services are self-contained functionalities that can be changed and/or modified in an isolated manner, without affecting other functionalities.

The services in a 5G CN are built in a stateless way, i.e. the business logic and data context is separated. This means that services store their context externally in a proprietary database (DB). This enables various cloud infrastructure features, such as auto-scaling and/or auto-healing. Also, the services are deployed as part of a Network Function (NF). 3GPP TS 23.501 defines a NF as a 3GPP adopted or 3GPP defined processing function in a 5G network, which has defined functional behaviour and 3GPP defined interfaces. In a 5G network, multiple NF instances may be deployed in a set, as long as these instances have access to the same context data.

As illustrated in Figure 1 , one NF instance is always supplied by a single vendor, including multiple services (as standardized by 3GPP). Each service may be instantiated in a pool and have access to a storage resource that may be shared by other services in the NF instance. However, this is dependent on implementation and deployment, rather than being standardized by 3GPP.

As illustrated in Figure 2, one or multiple NF instances, in the same or different Data Centers (DCs), may be deployed in the same NF set. This means that those instances provide the same business logic and have access to the same data. The access to the same data may be by different means, providing different levels of data consistency, e.g. if replication is required among locally deployed storage resources, this replication may be synchronous or asynchronous. In order to have access to the same data, all the NF instances in an NF set are by same vendor as the data is not standardized. As illustrated in Figure 3, it may also be possible that an NF instance spans multiple DCs.

However, an issue exists in that there is currently no resolution for an operator if an NF set fails or is decommissioned, e.g. by operation and maintenance (O&M) or by specific events. As such, there is a need for an improved technique, which is aimed at addressing this problem.

Summary

It is thus an object to obviate or eliminate at least some of the above disadvantages associated with existing techniques and provide an improved technique.

Therefore, according to an aspect of the idea, there is provided a method of operating a first network function (NF) node for execution of a service operation. The first NF node is a provider of a first service. The method comprises, in response to a request from a second service of a second NF node for execution of a service operation of the first service, initiating a transfer of context data to a third NF node with a transfer of the service operation of the first service to the third NF node. The context data comprises data required for the service operation of the first service to be executed.

In some embodiments, the transfer of context data may be initiated by the first service of the first NF node in response to information from an operation and maintenance procedure and/or the first service of the first NF node in response to an event at the first NF node or an event at another NF node of which the first NF node is informed. In some embodiments, the information from the operation and maintenance procedure is indicative that load balancing is required to reduce the load of the first NF node and the event is indicative of a load of the first NF node reaching a maximum threshold.

In some embodiments, the method may comprise identifying the context data prior to initiating the transfer of context data, locking the context data prior to initiating the transfer of the context data, and/or adapting the context data to a standard format valid for the third NF node prior to initiating the transfer of the context data.

In some embodiments, the method may comprise initiating a transfer of additional context data to the third NF node with the transfer of the context data. In some of these embodiments, the additional context data may comprise data that is not required for the service operation of the first service to be executed.

In some embodiments, the method may comprise receiving a response from the third NF node. In some of these embodiments, the response may comprise an indication that subsequent execution of the service operation of the first service is to be performed by the third NF node and/or an indication that identifies the third NF node.

According to another aspect of the idea, there is provided a first NF node configured to operate in accordance with the method described earlier.

In some embodiments, the first NF node may comprise processing circuitry and at least one memory for storing instructions which, when executed by the processing circuitry, cause the first NF node to operate in accordance with the method described earlier.

According to another aspect of the idea, there is provided a method of operating a third network function (NF) node for execution of a service operation. The third NF node is a provider of a first service. The method comprises, in response to a first NF node initiating a transfer of context data to the third NF node with a transfer of a service operation of the first service to the third NF node, executing the service operation of the first service using the context data. The context data comprises data required for the service operation of the first service to be executed. The transfer of context data is in response to a request from a second service of a second NF node for execution of the service operation of the first service.

In some embodiments, the method may comprise creating a resource to execute the service operation of the first service, storing the context data in a memory of the third NF node, processing the context data to restore other data for use in executing the service operation of the first service, and/or updating the context data following the execution of the service operation of the first service. In some embodiments, the method may comprise initiating a transfer of a response to the first NF node. In some of these embodiments, the response may comprise an indication that subsequent execution of the service operation of the first service is to be performed by the third NF node and/or an indication that identifies the third NF node.

According to another aspect of the idea, there is provided a third NF node configured to operate in accordance with the method described earlier. In some embodiments, the third NF node may comprise processing circuitry and at least one memory for storing instructions which, when executed by the processing circuitry, cause the third NF node to operate in accordance with the method described earlier. According to another aspect of the idea, there is provided a method of operating a second network function (NF) node for execution of a service operation. The second NF node implements a second service that is a consumer of a first service. The method comprises initiating a request for execution of a service operation of the first service to cause the initiation of a transfer of context data to a third NF node with a transfer of the service operation of the first service to the third NF node. The context data comprises data required for the service operation of the first service to be executed.

In some embodiments, the request may be initiated in response to information from an operation and maintenance procedure or the request is initiated in response to an event at the second NF node.

In some embodiments, the method comprises receiving a response from the first NF node or from a single point of access (SPoA) for a set of network functions comprising the third NF node. In some of these embodiments, the response may comprise an indication that subsequent execution of the service operation of the first service is to be performed by the third NF node.

According to another aspect of the idea, there is provided a second NF node configured to operate in accordance with the method described earlier. In some embodiments, the second NF node may comprise processing circuitry and at least one memory for storing instructions which, when executed by the processing circuitry, cause the second NF node to operate in accordance with the method described earlier.

According to another aspect of the idea, there is provided a computer program comprising instructions which, when executed by processing circuitry, cause the processing circuitry to perform the method described earlier.

According to another aspect of the idea, there is provided a computer program product, embodied on a non-transitory machine-readable medium, comprising instructions which are executable by processing circuitry to cause the processing circuitry to perform the method described earlier.

Therefore, an improved technique for the execution of a service operation is provided. Brief description of the drawings For a better understanding of the idea, and to show how it may be put into effect, reference will now be made, by way of example, to the accompanying drawings, in which:

Figure 1 is a block diagram illustrating the construction of an NF instance;

Figure 2 is a block diagram illustrating the construction of an NF set with more than one NF instance;

Figure 3 is a block diagram illustrating an NF instance spanning multiple DCs;

Figure 4 is a block diagram illustrating an NF according to an embodiment;

Figure 5 is a block diagram illustrating a method of operating an NF node according to an embodiment; Figure 6 is a block diagram illustrating a method of operating an NF node according to an embodiment;

Figure 7 is a block diagram illustrating an NF node according to an embodiment;

Figure 8 is a block diagram illustrating a method of operating an NF node according to an embodiment;

Figure 9 is a block diagram illustrating a method of operating an NF node according to an embodiment;

Figure 10 is a block diagram illustrating an NF node according to an embodiment;

Figure 1 1 is a block diagram illustrating a method of operating an NF node according to an embodiment;

Figure 12(a)-(c) is a signalling diagram illustrating an exchange of signals in an embodiment;

Figure 13(a)-(b) is a signalling diagram illustrating an exchange of signals in an embodiment;

Figure 14(a)-(c) is a signalling diagram illustrating an exchange of signals in an embodiment;

Figure 15(a)-(b) is a signalling diagram illustrating an exchange of signals in an embodiment;

Figure 16(a)-(b) is a signalling diagram illustrating an exchange of signals in an embodiment;

Figure 17 is a block diagram illustrating an NF node according to an embodiment;

Figure 18 is a block diagram illustrating an NF node according to an embodiment; and Figure 19 is a block diagram illustrating an NF node according to an embodiment. Detailed Description

There is described herein an improved technique for use in the execution of a service operation. The technique is implemented by way of one or more NF nodes (or NF instances). Examples of an NF node include, but are not limited to, an Access and Mobility Management function (AMF) node, a Session Management Function (SMF) node, a Policy Control function (PCF) node, a Unified Data Management (UDM) node, an Application Function (AF) node, a User plane Function (UPF) node, an Authentication Server Function (AUSF) node, or any other NF node.

The intention of an operator is to deploy at least two different sets of the same NF type, each one by a different vendor. Then, if one set fails or is decommissioned, the operator has the option to start using another set. That is, if a Set 1 fails or is decommissioned, the operator has the option to start using a Set 2. In order to continue processing as close as possible from the state that Set 1 reached before failing or being decommissioned, it has been recognised by the inventors of the present application that some of the context data stored in Set 1 (e.g. user equipment (UE) context data and/or protocol data unit (PDU) session related context data) needs to be transferred to Set 2. The context data that is required to be transferred may vary but, in any case, it needs to be enough to allow the receiver Set, i.e. Set 2, to re-build the processing state as close as it was in Set 1 , e.g. to allow the receiver to restore internal business logic state in order to continue processing.

A procedure to achieve this is described herein. It may be assumed that there is a standardized subset of attributes to be transferred defined in 3GPP for each specific context data to be transferred, which is not identical, but may be mapped to a subset of the context data (e.g. UE-related and/or PDU Session data) stored in the network functions, NFs. A limited amount of context data can be transferred, but enough for the receiver to restore an internal business logic state. A desirable feature of the transfers is to impact the SBA services business logic as little as possible, which includes also the serial based interfaces (SBIs) provided and the service operations involving those SBIs. The context data to be transferred is the data required for the service operation execution but also be additional context data, such as associated data (e.g. data that may be used by other services as well), which may be transferred at the same time to ensure consistency.

Figure 4 illustrates a first NF node (or first NF instance) 10 for execution of a service operation in accordance with an embodiment. The first NF node 10 is a provider of a first service. Herein, the first service may also be referred to as“Service A”. In some embodiments, the first NF node 10 may be deployed in a first set of NF nodes (“Set 1”). That is, a first set of NF nodes (“Set 1”) may comprise the first NF node 10 according to some embodiments. However, in other embodiments, the first NF node 10 may be a single node. That is, the first NF node 10 may not be part of any set according to other embodiments.

As illustrated in Figure 4, the first NF node 10 comprises processing circuitry (or logic) 12. The processing circuitry 12 controls the operation of the first NF node 10 and can implement the method described herein in respect to the first NF node 10. The processing circuitry 12 can comprise one or more processors, processing units, multi core processors or modules that are configured or programmed to control the first NF node 10 in the manner described herein. In particular implementations, the processing circuitry 12 can comprise a plurality of software and/or hardware modules that are each configured to perform, or are for performing, individual or multiple steps of the method described herein.

Briefly, the processing circuitry 12 of the first NF node 10 is configured to, in response to a request from a second service of a second NF node for execution of a service operation of the first service, initiate a transfer of context data to a third NF node with a transfer of the service operation of the first service to the third NF node. The context data comprises data required for the service operation of the first service to be executed. The first NF node 10 may operate in the manner described herein. Herein, the second service may be referred to as“service B”. Also, herein, the request for execution of the service operation of the first service may be referred to as “an operation request”,“a service operation request”,“an operation execution request”, or “a service operation execution request”.

As illustrated in Figure 4, the first NF node 10 may optionally comprise a memory 14. The memory 14 of the first NF node 10 can comprise a volatile memory or a non- volatile memory. In some embodiments, the memory 14 of the first NF node 10 may comprise a non-transitory media. Examples of the memory 14 of the first NF node 10 include, but are not limited to, a random access memory (RAM), a read only memory (ROM), a mass storage media such as a hard disk, a removable storage media such as a compact disk (CD) or a digital video disk (DVD), and/or any other memory.

The processing circuitry 12 of the first NF node 10 can be connected to the memory 14 of the first NF node 10. In some embodiments, the memory 14 of the first NF node 10 may be for storing program code or instructions which, when executed by the processing circuitry 12 of the first NF node 10, cause the first NF node 10 to operate in the manner described herein in respect of the first NF node 10. For example, in some embodiments, the memory 14 of the first NF node 10 may be configured to store program code or instructions that can be executed by the processing circuitry 12 of the first NF node 10 to perform the method described herein in respect of the first NF node 10.

Alternatively or in addition, the memory 14 of the first NF node 10 can be configured to store any requests, responses, indications, information, data, notifications, signals, or similar, that are described herein. The processing circuitry 12 of the first NF node 10 may be configured to control the memory 14 of the first NF node 10 to store any requests, responses, indications, information, data, notifications, signals, or similar, that are described herein.

In some embodiments, as illustrated in Figure 4, the first NF node 10 may optionally comprise a communications interface 16. The communications interface 16 of the first NF node 10 can be connected to the processing circuitry 12 of the first NF node 10 and/or the memory 14 of the first NF node 10. The communications interface 16 of the first NF node 10 may be operable to allow the processing circuitry 12 of the first NF node 10 to communicate with the memory 14 of the first NF node 10 and/or vice versa. The communications interface 16 of the first NF node 10 can be configured to transmit and/or receive any requests, responses, indications, information, data, notifications, signals, or similar, that are described herein. In some embodiments, the processing circuitry 12 of the first NF node 10 may be configured to control the communications interface 16 of the first NF node 10 to transmit and/or receive any requests, responses, indications, information, data, notifications, signals, or similar, that are described herein.

Although the first NF node 10 is illustrated in Figure 4 as comprising a single memory 14, it will be appreciated that the first NF node 10 may comprise at least one memory (i.e. a single memory or a plurality of memories) 14 that operate in the manner described herein. Similarly, although the first NF node 10 is illustrated in Figure 4 as comprising a single communications interface 16, it will be appreciated that the first NF node 10 may comprise at least one communications interface (i.e. a single communications interface or a plurality of communications interface) 16 that operate in the manner described herein.

It will also be appreciated that Figure 4 only shows the components required to illustrate an embodiment of the first NF node 10 and, in practical implementations, the first NF node 10 may comprise additional or alternative components to those shown.

Figure 5 is a flowchart illustrating a method of operating a first NF node (or first NF instance) 10 for execution of a service operation in accordance with an embodiment. The first NF node 10 (e.g. the first service of the first NF node 10) described earlier with reference to Figure 4 is configured to operate in accordance with the method of Figure 5. The method can be performed by or under the control of the processing circuitry 12 of the first NF node 10. With reference to Figure 5, at block 100, in response to a request from a second service of a second NF node for execution of a service operation of the first service, a transfer of context data is initiated to a third NF node with a transfer of the service operation of the first service to the third NF node. Any one or more NF nodes (e.g. of the first set of NF nodes) and/or any one or more services (e.g. of a first set of services) may be operable to perform the method of Figure 5.

Figure 6 is a flowchart illustrating a method of operating a first NF node (or first NF instance) 10 for execution of a service operation in accordance with another embodiment. The first NF node 10 (e.g. the first service of the first NF node 10) described earlier with reference to Figure 4 may, in some embodiments, be configured to operate in accordance with the method of Figure 6. The method can be performed by or under the control of the processing circuitry 12 of the first NF node 10. In more detail, Figure 6 shows a flowchart with sender (“Service A”) entity logic for the idea. The numbering inside the blocks is used to display the steps of Figure 6 in the call flow illustrated in Figure 12(a)-(c). Any one or more NF nodes (e.g. of the first set of NF nodes) and/or any one or more services (e.g. of a first set of services) may be operable to perform the method of Figure 6.

With reference to Figure 6, at block 102, an operation request is received. The operation request may include a flag for context transfer. Alternatively or in addition, the operation request may include a destination for the operation request. At block 104, context data associated with the service operation is identified and the identified context data is prepared for transfer. At block 106, the service operation is sent to the destination with the associated context data. At block 108, a response is transmitted. This response may also may be referred to herein as“an operation response”, “a service operation response”,“an operation execution response”, or“a service operation execution response”.

Figure 7 illustrates a third NF node (or third NF instance) 20 for execution of a service operation in accordance with an embodiment. The third NF node 20 is a provider of a first service, which may also be referred to herein as “Service A”. In some embodiments, the third NF node 20 may be deployed in a second set of NF nodes (“Set 2”). That is, a second set of NF nodes (“Set 2”) may comprise the third NF node 20 according to some embodiments. However, in other embodiments, the third NF node 20 may be a single node. That is, the third NF node 20 may not be part of any set according to other embodiments.

As illustrated in Figure 7, the third NF node 20 comprises processing circuitry (or logic) 22. The processing circuitry 22 controls the operation of the third NF node 20 and can implement the method described herein in respect to the third NF node 20. The processing circuitry 22 can comprise one or more processors, processing units, multi core processors or modules that are configured or programmed to control the third NF node 20 in the manner described herein. In particular implementations, the processing circuitry 22 can comprise a plurality of software and/or hardware modules that are each configured to perform, or are for performing, individual or multiple steps of the method described herein. Briefly, the processing circuitry 22 of the third NF node 20 is configured to, in response to a first NF node initiating a transfer of context data to the third NF node 20 with a transfer of a service operation of the first service to the third NF node 20, execute the service operation of the first service using the context data. The context data comprises data required for the service operation of the first service to be executed. The transfer of context data is in response to a request from a second service of a second NF node for execution of the service operation of the first service. The third NF node 20 may operate in the manner described herein.

As illustrated in Figure 7, the third NF node 20 may optionally comprise a memory 24. The memory 24 of the third NF node 20 can comprise a volatile memory or a non volatile memory. In some embodiments, the memory 24 of the third NF node 20 may comprise a non-transitory media. Examples of the memory 24 of the third NF node 20 include, but are not limited to, a random access memory (RAM), a read only memory (ROM), a mass storage media such as a hard disk, a removable storage media such as a compact disk (CD) or a digital video disk (DVD), and/or any other memory.

The processing circuitry 22 of the third NF node 20 can be connected to the memory 24 of the third NF node 20. In some embodiments, the memory 24 of the third NF node 20 may be for storing program code or instructions which, when executed by the processing circuitry 22 of the third NF node 20, cause the third NF node 20 to operate in the manner described herein in respect of the third NF node 20. For example, in some embodiments, the memory 24 of the third NF node 20 may be configured to store program code or instructions that can be executed by the processing circuitry 22 of the third NF node 20 to perform the method described herein in respect of the third NF node 20.

Alternatively or in addition, the memory 24 of the third NF node 20 can be configured to store any requests, responses, indications, information, data, notifications, signals, or similar, that are described herein. The processing circuitry 22 of the third NF node 20 may be configured to control the memory 24 of the third NF node 20 to store any requests, responses, indications, information, data, notifications, signals, or similar, that are described herein. In some embodiments, as illustrated in Figure 7, the third NF node 20 may optionally comprise a communications interface 26. The communications interface 26 of the third NF node 20 can be connected to the processing circuitry 22 of the third NF node 20 and/or the memory 24 of the third NF node 20. The communications interface 26 of the third NF node 20 may be operable to allow the processing circuitry 22 of the third NF node 20 to communicate with the memory 24 of the third NF node 20 and/or vice versa. The communications interface 26 of the third NF node 20 can be configured to transmit and/or receive any requests, responses, indications, information, data, notifications, signals, or similar, that are described herein. In some embodiments, the processing circuitry 22 of the third NF node 20 may be configured to control the communications interface 26 of the third NF node 20 to transmit and/or receive any requests, responses, indications, information, data, notifications, signals, or similar, that are described herein.

Although the third NF node 20 is illustrated in Figure 7 as comprising a single memory 24, it will be appreciated that the third NF node 20 may comprise at least one memory (i.e. a single memory or a plurality of memories) 24 that operate in the manner described herein. Similarly, although the third NF node 20 is illustrated in Figure 7 as comprising a single communications interface 26, it will be appreciated that the third NF node 20 may comprise at least one communications interface (i.e. a single communications interface or a plurality of communications interface) 26 that operate in the manner described herein.

It will also be appreciated that Figure 7 only shows the components required to illustrate an embodiment of the third NF node 20 and, in practical implementations, the third NF node 20 may comprise additional or alternative components to those shown.

Figure 8 is a flowchart illustrating a method of operating a third NF node (or third NF instance) 20 for execution of a service operation in accordance with an embodiment. The third NF node 20 (e.g. the first service of the third NF node 20) described earlier with reference to Figure 7 is configured to operate in accordance with the method of Figure 8. The method can be performed by or under the control of the processing circuitry 22 of the third NF node 20. With reference to Figure 8, at block 200, in response to a first NF node initiating a transfer of context data to the third NF node 20 with a transfer of a service operation of the first service to the third NF node, the service operation of the first service is executed using the context data. The context data comprises data required for the service operation of the first service to be executed. The transfer of context data is in response to a request from a second service of a second NF node for execution of the service operation of the first service. Any one or more NF nodes (e.g. of the second set of NF nodes) and/or any one or more services (e.g. of a second set of services) may be operable to perform the method of Figure 8.

Figure 9 is a flowchart illustrating a method of operating a third NF node (or third NF instance) 20 for execution of a service operation in accordance with another embodiment. The third NF node 20 described earlier with reference to Figure 7 may, in some embodiments, be configured to operate in accordance with the method of Figure 9. The method can be performed by or under the control of the processing circuitry 22 of the third NF node 20.

In more detail, Figure 9 shows a flowchart with the consumer (“Service B”) entity logic for the idea. The numbering inside the blocks is used to display the steps of Figure 9 in the call flow illustrated in Figure 12(a)-(c). With reference to Figure 9, at block 202, context data transfer is triggered. This can be triggered per operation request. At block 204, regular business logic is executed and the operation request is sent. The operation request may include a flag for context transfer. Alternatively or in addition, the operation request may include a destination for the operation request. At block 206, a response is received. This response may also may be referred to herein as“an operation response”, “a service operation response”, “an operation execution response”, or a“service operation execution response”. The response may include the new destination (or location) for the execution of the service operation. At block 208, generic keys are updated to the new destination (and conditionally, new Resource Id) mapping. The generic keys may be, for example, subscription permanent identifier (SUPI), protocol data unit (PDU) Session Id, etc.

Figure 10 illustrates a second NF node (or second NF instance) 30 for execution of a service operation in accordance with an embodiment. The second NF node 30 implements a second service. The second service is a consumer of a first service, which may also be referred to herein as“Service A”. Herein, the second service may also be referred to as“Service B”. In some embodiments, the second NF node 30 may be deployed in a third set of NF nodes. That is, a third set of NF nodes may comprise the second NF node 30 according to some embodiments. However, in other embodiments, the second NF node 30 may be a single node. That is, the second NF node 30 may not be part of any set according to other embodiments.

As illustrated in Figure 10, the second NF node 30 comprises processing circuitry (or logic) 32. The processing circuitry 32 controls the operation of the second NF node 30 and can implement the method described herein in respect to the second NF node 30. The processing circuitry 32 can comprise one or more processors, processing units, multi-core processors or modules that are configured or programmed to control the second NF node 30 in the manner described herein. In particular implementations, the processing circuitry 32 can comprise a plurality of software and/or hardware modules that are each configured to perform, or are for performing, individual or multiple steps of the method described herein.

Briefly, the processing circuitry 32 of the second NF node 30 is configured to, initiate a request from the second service of the second NF node 30 for execution of a service operation of the first service to cause the initiation of a transfer of context data to a third NF node with a transfer of the service operation of the first service to the third NF node. The context data comprises data required for the service operation of the first service to be executed. The second NF node 30 may operate in the manner described herein.

As illustrated in Figure 10, the second NF node 30 may optionally comprise a memory 34. The memory 34 of the second NF node 30 can comprise a volatile memory or a non-volatile memory. In some embodiments, the memory 34 of the second NF node 30 may comprise a non-transitory media. Examples of the memory 34 of the second NF node 30 include, but are not limited to, a random access memory (RAM), a read only memory (ROM), a mass storage media such as a hard disk, a removable storage media such as a compact disk (CD) or a digital video disk (DVD), and/or any other memory.

The processing circuitry 32 of the second NF node 30 can be connected to the memory 34 of the second NF node 30. In some embodiments, the memory 34 of the second NF node 30 may be for storing program code or instructions which, when executed by the processing circuitry 32 of the second NF node 30, cause the second NF node 30 to operate in the manner described herein in respect of the second NF node 30. For example, in some embodiments, the memory 34 of the second NF node 30 may be configured to store program code or instructions that can be executed by the processing circuitry 32 of the second NF node 30 to perform the method described herein in respect of the second NF node 30.

Alternatively or in addition, the memory 34 of the second NF node 30 can be configured to store any requests, responses, indications, information, data, notifications, signals, or similar, that are described herein. The processing circuitry 32 of the second NF node 30 may be configured to control the memory 34 of the second NF node 30 to store any requests, responses, indications, information, data, notifications, signals, or similar, that are described herein.

In some embodiments, as illustrated in Figure 10, the second NF node 30 may optionally comprise a communications interface 36. The communications interface 36 of the second NF node 30 can be connected to the processing circuitry 32 of the second NF node 30 and/or the memory 34 of the second NF node 30. The communications interface 36 of the second NF node 30 may be operable to allow the processing circuitry 32 of the second NF node 30 to communicate with the memory 34 of the second NF node 30 and/or vice versa. The communications interface 36 of the second NF node 30 can be configured to transmit and/or receive any requests, responses, indications, information, data, notifications, signals, or similar, that are described herein. In some embodiments, the processing circuitry 32 of the second NF node 30 may be configured to control the communications interface 36 of the second NF node 30 to transmit and/or receive any requests, responses, indications, information, data, notifications, signals, or similar, that are described herein.

Although the second NF node 30 is illustrated in Figure 10 as comprising a single memory 34, it will be appreciated that the second NF node 30 may comprise at least one memory (i.e. a single memory or a plurality of memories) 34 that operate in the manner described herein. Similarly, although the second NF node 30 is illustrated in Figure 10 as comprising a single communications interface 36, it will be appreciated that the second NF node 30 may comprise at least one communications interface (i.e. a single communications interface or a plurality of communications interface) 36 that operate in the manner described herein.

It will also be appreciated that Figure 10 only shows the components required to illustrate an embodiment of the second NF node 30 and, in practical implementations, the second NF node 30 may comprise additional or alternative components to those shown.

Figure 11 is a flowchart illustrating a method of operating a second NF node (or second NF instance) 30 for execution of a service operation in accordance with an embodiment. The second NF node 30 (e.g. the second service of the second NF node 30) described earlier with reference to Figure 10 is configured to operate in accordance with the method of Figure 1 1. The method can be performed by or under the control of the processing circuitry 32 of the second NF node 30.

With reference to Figure 1 1 , at block 300, a request is initiated from the second service of the second NF node 30 for execution of a service operation of the first service to cause the initiation of a transfer of context data to a third NF node with a transfer of the service operation of the first service to the third NF node. The context data comprises data required for the service operation of the first service to be executed. Any one or more NF nodes (e.g. of the third set of NF nodes) and/or any one or more services (e.g. of a third set of services) may be operable to perform the method of Figure 1 1.

Although not illustrated in the earlier described figures, there is also provided a network and, more specifically, a core network (CN) comprising any one or more of the first NF node 10 described herein, the second NF node 30 described herein and the third NF node 20 described herein.

Figure 12(a)-(c) is a signalling (or call flow) diagram illustrating an exchange of signals in an embodiment. The exchange of signals is in a CN, which comprises a first NF node 10, a second NF node 30 (not illustrated), and a third NF node 20. The first NF node 10 is as described earlier with reference to Figure 4, the second NF node 30 is as described earlier with reference to Figure 10, and the third NF node 20 is as described earlier with reference to Figure 7. The first NF node 10 is a provider of a first service (“Service A”) 18. The third NF node 20 is also a provider of (e.g. another instance of) Service A 28. The second NF node 30 implements a second service 38 that is a consumer of Service A 18, 28. Herein, the second service will be referred to as “Service B” 38.

In the CN illustrated in Figure 12(a)-(c), a first set of NF nodes (“Set 1”) comprises the first NF node 10. That is, the first NF node 10 is deployed in Set 1 . A second set of NF nodes (“Set 2”) comprises the third NF node 20. That is, the third NF node 20 is deployed in Set 2. The CN comprises a single point of access (SPoA) 40 for the set of NFs comprising the first NF node 10, which is referred to herein as“Set 1 (SPoA)”. The CN also comprises a single point of access (SPoA) 50 for the set of NFs comprising the third NF node 20, which is referred to herein as“Set 2 (SPoA)”.

In the illustrated embodiment, the context data is transferred from the first NF node 10 to the second NF node 30. At block 800, access to context data in the first set of NF nodes (“Set 1”) is provided. Steps 1 to 8 in block 800 of the signalling in Figure 12(a)- (c) depict legacy operations, which illustrate communication patterns to/for the first NF node 10 before the context data is transferred. Steps from 1 to 8 describe a basic behaviour when a Service B 38 of the second NF node 30 wants to reach Service A. At block 802, operation context transfer is triggered. In this illustrated embodiment, this includes transfer of the service operation and an indication that context data is to be transferred. At block 804, context data is transferred and the service operation is executed. At block 806, a service operation response is initiated. In this illustrated embodiment, the service operation response comprises an indication that identifies the third NF node 20 (e.g. a location of the third NF node 20).

Further details regarding each step of the signalling in Figure 12(a)-(c) are provided below:

Step 1 - Service B (as a consumer in the second NF node 30, NF-Y) 38 needs to discover Service A (as a producer in the first NF node 10 and third NF node 20, NF-X). A discovery request is initiated at Service B 38. Service B 38 may either provide some selection criteria in the discovery request or it may perform a selection based on the discovery results. An address is selected to contact Service A. Step 2 - Service B 38 subscribes to an NF Repository Function (NRF), with Nnrf_NFManagement_NFSubscribe (NF-X profile updates & Deregistration), in order to receive information of the update of the NF-X status. In particular, in this use case, Service B 38 is interested in the destination NF-X set that is updated as part of the registration or with an NF update (see Step 10). This is a new attribute to be included into the NF-X instance profile.

Step 3 - Service B 38 (a consumer of service A 18, 28) requests a Service A operation, which is sent to an address obtained from the discovery and selection in Stepl . This address may identify an SPoA or one instance of Service A 18, 28.

Step 4 - Any instance of Set 1 is potentially reachable, one instance in the set may be selected based on various criteria (e.g. load). One instance in Set 1 is attempted to be selected and the Service A operation request is forwarded to this set.

Step 5 - Context data may be read from the memory (e.g. a storage resource) 14 of this set. This is the unique place where the context data is stored and up- to-date. Note that the storage resource 14 is shown as being part of the first NF node 10 of Set 1 . The storage resource 14 may alternatively be elsewhere in the set. This is rather a logical relation showing that only the NF nodes of a given set may reach the storage resource 14. In other examples, the storage resource 14 can be a separate entity, e.g. a data storage network function (UDSF).

Step 6 - After the first NF node 10 executes its processing circuitry (or logic, e.g.

business logic) 12, if the context data is modified, the context data may be updated in the storage resource 14.

Step 7-8 - A response is initiated from Service A 18 of the first NF node 10 to Service

B 38 of the second NF node 30. The response indicates that the Service A operation requests is successful. Step 9 - An internal event is interpreted by Service B 38 as the need to transfer context data. This may be, for example, that Set 1 is reaching a maximum load threshold (producer load and capacity can be information comprised in the NF profile in NRF). Alternatively, the trigger may not be an internal event, but Service B 38 may receive an external indication that context data is to be transferred, e.g. by an operation and maintenance procedure (O&M) or by another NF (which may end up being the receiver of the context data). In this example, it is considered that Service B 38 knows which NF node is to be the destination set (Set 2). However, it may be known by other means. For example, it may be configured, or provided by another NF, or by O&M. Alternatively, Service B 38 may incorporate logic to be able to select a destination set, e.g. based on capabilities of the receiver set, configuration, etc.

Step 10 - As described earlier (e.g. with reference to Figure 1 1 ), a request is initiated from the second service 38 of the second NF node 30 (e.g. via a context transfer requester 60) for execution of the service operation of the first service to cause the initiation of the transfer of context data to the third NF node 20 with a transfer of the service operation of the first service to the third NF node 20. Service B 38 wants to execute Service A operation, which remains the same operation, but newly extended with an indication that provides the information that the context data is to be transferred. It refers to the context data that this operation needs to access and potentially modify, but may also refer to the additional (e.g. related) context data. The additional context data may be context data that is read/modified when accessing the context data required for that Service A operation (see Step 13). The Service A operation may also newly include information about the destination set.

Step 1 1 - The Service A operation may reach an SPoA for the NF nodes that are part of the same set (Set 1 ). For example, the Service A operation may reach Set 1 (SPoA) 40. A single entity is selected, e.g. based on internal criteria such as load. Step 12 - From the indication included in the Service A operation (that context data is to be transferred), Service A 18 identifies that it is not to execute business logic locally, but it is to forward the Service A operation with context data to the destination, which may also be included the indication. This is executed in steps 12 to 26. In this example, it is considered that the processing circuitry 12 of the first NF node 10 has the functionality (“Context Transfer”) responsible to perform some tasks for context data transfer. If this functionality in the example is not considered as an independent service-based architecture (SBA) service, then no new service operations are required. From an SBA perspective, it may be interpreted as part of Service A 18, 28. From a software (SW) implementation point of view, it may be a different SW module. Alternatively, context data transfer may be defined as a new SBA service. Step 13 - Context data is identified. This includes the context data required to execute the Service A operation and may also include additional context data (e.g. to ensure data consistency, all related context data may be stored in the same place, avoiding that part of it is modified without updating any other related context data to that modification).

Step 14 - The identified context data is read from the corresponding storage resource

14, which stores context data for Set 1 . This context data may be locked for writing operations since it is to be transferred to a new destination. Modification may not be allowed to avoid causing data inconsistency, since any updates after Step 14 are not be transferred. If this access is proprietary, then each implementation may have a different data structure.

Step 15 - The context data (implementation specific) may be adapted to standardized context data. It can be advantageous that the context data to be transferred is standardized, e.g. the context data transfer may to be between different vendors implementations. It may be that the context data that is required by the service operation is already standardized and only any additional context data is to be standardize at Step 15. The amount of context data to be standardized may vary for each service and service operation. Some context data may be re-built at the destination (e.g. based on the transferred context data), which avoids the need to transfer all context data.

Step 16 As described earlier (e.g. with reference to Figure 5), in response to a request from the second service of the second NF node 30 for execution of a service operation of the first service, a transfer of context data is initiated to the third NF node 20 with a transfer of the service operation of the first service to the third NF node 20. Here, the same Service A operation is sent to the destination Service A 28 of the third NF node 20. The Service A operation is extended to include the context data to be transferred, which includes the context data required for execution of the Service A operation and may optionally also include additional context data.

Step 17 The Set 2 (SPoA) 50 may be used, as indicated in Step 1 1.

Step 18 At reception of the Service A operation, as it contains context data, Service

A 28 of the third NF node 20 can identify that this corresponds to a transfer. Service A 28 of the third NF node 20 may create a new resource, e.g. which may be applicable to a hypertext transfer protocol (HTTP).

Step 19 The received context data may be stored in a storage resource of Set 2, such as a storage resource (or the memory) of the third NF node 20. This storage may occur before execution of the service A operation (Step 21 ) to ensure any context data that may be required for other services in the same NF for the operation execution is already available.

Step 20 - Once the context data is transferred to the third NF node 20 of Set 2, in some cases, the context data may be processed to restore the state, e.g. to restore internal data from the minimum amount of data that was conveyed (to minimize standardization), or contact other NFs/services that need derived updates. The option of whether or not to process the context data may depend on the amount of context data that is to be standardized (as explained above), and/or on the specific business logic of each service. Step 21 - As described earlier, in response to the first NF node 10 initiating a transfer of context data to the third NF node 20 with the transfer of the service operation of the first service to the third NF node 20, the service operation of the first service is executed using the context data. It may be that the original Service A operation (in step 10) has not previously been executed at the destination, namely at the third NF node 20 of Set2.

Step 22 - As a result of the operation execution, some context data may be updated. Step 23 An operation response to the service A operation request is transmitted, which may include an indication that identifies the third NF node (e.g. a location of the third NF node or a new resource if created in Step 18).

Step 24 The operation response may be sent via the Set 2 (SPoA) 50.

Step 25 When the first NF node 10 of Set 1 (e.g. Context Transfer in Service A 18) receives the operation response, if successful, it may update the storage resource 14 with an indication that there is a new destination for the context data. If the location of the new destination is available, this location may also be stored.

Step 26 - As indicated in step 12, the processing circuitry 12 of the first NF node 10 may comprise context transfer functionality as a specific functionality for transferring the context data. In this case, the context transfer functionality may forward the operation response to Service A 18 at the first NF node 10. In some embodiments, the context transfer functionality may be a part of Service A 18 (e.g. from an SBA perspective).

Step 27 - The operation response may reach Service B 38 via the Set1 (SPoA) 40.

Step 28 - The operation response is received by Service B 38 of the second NF node

30. The operation response may include at least an indication of the new destination set (Set 2). If a new resource is created in Step 18, the operation response may include location information (e.g. a reference to the newly created context in Set 2). Step 29 - Service B 38 of the second NF node 30 may update at least that, for this context data, the new destination is Set 2. Additionality, if the location is included, it may update local mapping, e.g. from general keys (such as SUPI, PDU, Session id, etc.) to the newly created resource.

Figure 13(a)-(b) is a signalling (or call flow) diagram illustrating an exchange of signals in an embodiment. The exchange of signals is in a CN, which comprises a first NF node 10, a second NF node 30 (not illustrated), and a third NF node 20. The first NF node 10 is as described earlier with reference to Figure 4, the second NF node 30 is as described earlier with reference to Figure 10, and the third NF node 20 is as described earlier with reference to Figure 7. The first NF node 10 is a provider of a first service (“Service A”) 18. The third NF node 20 is also a provider of (e.g. another instance of) Service A 28. The second NF node 30 implements a second service 38 that is a consumer of Service A 18, 28. Herein, the second service will be referred to as “Service B” 38.

In the CN illustrated in Figure 13(a)-(b), a first set of NF nodes (“Set 1”) comprises the first NF node 10. That is, the first NF node 10 is deployed in Set 1 . A second set of NF nodes (“Set 2”) comprises the third NF node 20. That is, the third NF node 20 is deployed in Set 2. The CN comprises a single point of access (SPoA) 40 for the set of

NFs comprising the first NF node 10, which is referred to herein as“Set 1 (SPoA)”. The CN also comprises a single point of access (SPoA) 50 for the set of NFs comprising the third NF node 20, which is referred to herein as“Set 2 (SPoA)”.

In the illustrated embodiment, the context data is transferred from the first NF node 10 to the second NF node 30. At block 900, access to context data in the first set of NF nodes (“Set 1”) is provided. Steps 1 to 8 in block 900 of the signalling in Figure 13(a)- (b) depict legacy operations, which illustrate communication patterns to/for the first NF node 10 before the context data is transferred. Steps from 1 to 8 describe a basic behaviour when a Service B 38 of the second NF node 30 wants to reach Service A.

Steps 1 to 8 are as described earlier with respect to Figure 12(a)-(c). At block 902, operation context transfer is triggered. In this illustrated embodiment, this includes transfer of the service operation but not an indication that context data is to be transferred. At block 904, context data is transferred and the service operation is executed. At block 906, a service operation response is initiated. In this illustrated embodiment, the service operation response comprises an indication that identifies the third NF node 20 (e.g. a location of the third NF node 20).

In contrast to Figure 12(a)-(c), Step 9 of Figure 13(a)-(b) is performed by Service A 18 of the first NF node 10. This means that, in Steps 10 and 1 1 , the service A operations do not need to be extended. Steps 12 to 15 of Figure 13(a)-(b) are as described earlier with respect to Steps 13 to 16 of Figure 12(a)-(c) respectively, except that Service A 18 of the first NF node 10 performs the steps in Figure 13(a)-(b) (rather than the context transfer functionality performing the steps as in Figure 12(a)-(c)).

Steps 16 to 24 of Figure 13(a)-(b) are as described earlier with respect to Steps 17 to 25 of Figure 12(a)-(c) respectively, except that the operation response is sent to Service A 18 of the first NF node 10 in Step 23 of Figure 13(a)-(b) (rather than to the context transfer functionality as in Figure 12(a)-(c)). Thus, Service A 18 of the first NF node 10 performs the update at Step 24 of Figure 13(a)-(b) (rather than the context transfer functionality performing the update as in Step 25 of Figure 12(a)-(c)). Steps 25 to 27 of Figure 13(a)-(b) are as described earlier with respect to Steps 27 to 29 of Figure 12(a)-(c) respectively.

Thus, in Figure 13(a)-(b), a context data transfer enablement or activation flag is generated in Service A 18 of the first NF node 10 and logic of Service A 18 is extended to manage the context data transfer. There is no need for a new service, but just extension to include context data.

A variant may be to answer from the Set 2 (SPoA) directly to the Service B 38 of the second NF node 30, avoiding the operation response traversing Set 1. For example, in Figure 13(a)-(b), there may be a Step 23a going back to service B 38 (like Step 26) and, in parallel, a Step 23b (like Step 23) and the Step 24.

Another variant may be that the context data update and the answer to Service B 38 of the second NF node 30 happens directly from Set 1 . That is, the execution (in Step 20 of Figure 13(a)-(b)) and the operation response (in Step 25 of Figure 13(a)-(b)) may happen before Step 15 in Figure 13(a)-(b). This avoids the additional latency due to the context data preparation, transfer and activation to Set 2. Thus, as an alternative embodiment, operation may be executed locally to provide a response at that moment, while the service operation forwarded may be used only for context data transfer and not for business logic execution.

Figure 14(a)-(c) is a signalling (or call flow) diagram illustrating an exchange of signals in an embodiment. The exchange of signals is in a CN, which comprises a first NF node 10, a second NF node 30 (not illustrated), and a third NF node 20. The first NF node 10 is as described earlier with reference to Figure 4, the second NF node 30 is as described earlier with reference to Figure 10, and the third NF node 20 is as described earlier with reference to Figure 7. The first NF node 10 is a provider of a first service (“Service A”) 18. The third NF node 20 is also a provider of (e.g. another instance of) Service A 28. The second NF node 30 implements a second service 38 that is a consumer of Service A 18, 28. Herein, the second service will be referred to as “Service B” 38.

In the CN illustrated in Figure 14(a)-(c), a first set of NF nodes (“Set 1”) comprises the first NF node 10. That is, the first NF node 10 is deployed in Set 1. A second set of NF nodes (“Set 2”) comprises the third NF node 20. That is, the third NF node 20 is deployed in Set 2. The CN comprises a single point of access (SPoA) 40 for the set of NFs comprising the first NF node 10, which is referred to herein as“Set 1 (SPoA)”. The CN also comprises a single point of access (SPoA) 50 for the set of NFs comprising the third NF node 20, which is referred to herein as“Set 2 (SPoA)”.

In the illustrated embodiment, the context data is transferred from the first NF node 10 to the second NF node 30. At block 1000, access to context data in the first set of NF nodes (“Set 1”) is provided. Steps 1 to 8 in block 1000 of the signalling in Figure 14(a)- (c) depict legacy operations, which illustrate communication patterns to/for the first NF node 10 before the context data is transferred. Steps from 1 to 8 describe a basic behaviour when a Service B 38 of the second NF node 30 wants to reach Service A. Steps 1 to 8 are as described earlier with respect to Figure 12(a)-(c). At block 1002, operation context transfer is triggered. At block 1004, context data is transferred and the service operation is executed. At block 1006, a service operation response is initiated. In this illustrated embodiment, the service operation response comprises an indication that identifies the third NF node 20 (e.g. a location of the third NF node 20). In this illustrated embodiment, the operation context transfer includes the transfer of the service operation request directly to the destination. More particularly, at Steps 10 and 1 1 of Figure 14(a)-(c), Service B 38 of the third NF node 20 sends the service operation request directly to the destination. In this illustrated embodiment, the service operation request comprises the address/identification of the NF node that holds the context data, which is the first NF node of Set 1. At Step 12, it is the receiver Service A 28 of the third NF node 20 of Set 2 that requests the context data from the Service A 18 of the first NF node 10 of Set 1. Thus, at Step 16, the Service A 18 of the first NF node 10 of Set 1 transfers the context data to Service A 28 of the third NF node 20 of Set 2. This may be achieved by way of new operations, existing operations (that may already exist for context transfer purposes), or a possible extension of other operations.

Steps 13 to 15 of Figure 14(a)-(c) are as described earlier with respect to Steps 13 to 15 of Figure 12(a)-(c) respectively, except that Service A 18 of the first NF node 10 performs the steps in Figure 14(a)-(c) (rather than the context transfer functionality performing the steps as in Figure 12(a)-(c)). Steps 17 to 22 of Figure 13(a)-(b) are as described earlier with respect to Steps 18 to 23 of Figure 12(a)-(c) respectively. Then, it is the Set 2 SPoA 50 that provides the operation response to Service B 38 of the second NF node 30. The operation response may include at least an indication of the new destination set (Set 2). If a new resource is created in Step 17, the operation response may include location information (e.g. a reference to the newly created context in Set 2). Step 25 of Figure 14(a)-(c) is as described earlier with respect to Step 29 of Figure 12(a)-(c).

In some embodiments, after the last step of Figure 12(a)-(c), 13(a)-(b) or 14(a)-(c), the second service B 38 that initiated this context data transfer, may be updated with the information to reach the destination set (Set 2) and, if required, the location (e.g. URI) of the created resource. However, other services that are consumers of Service A may need to use same context data and thus may also need to reach it in the new destination. If another service is in the same set as Service B, then it may have access to the same data stored in the last step of Figure 12(a)-(c), 13(a)-(b) or 14(a)-(c). However, for any other consumer that is not in the same set, extra means needs to be employed and one example will now be described with reference to Figure 15(a)-(b). Figure 15(a)-(b) is a signalling (or call flow) diagram illustrating an exchange of signals in an embodiment. The exchange of signals is in a CN, which comprises a first NF node 10, a third NF node 20, and a fourth NF node (not illustrated).

The first NF node 10 is as described earlier with reference to Figure 4 and the third NF node 20 is as described earlier with reference to Figure 7. The fourth NF node is as described earlier with reference to Figure 10 for the second NF node 30. The first NF node 10 is a provider of a first service (“Service A”) 18. The third NF node 20 is also a provider of (e.g. another instance of) Service A 28. The fourth NF node implements a third service 70 that is a consumer of Service A 18, 28. The third service will be referred to as“Service C” 70.

In the CN illustrated in Figure 15(a)-(b), a first set of NF nodes (“Set 1”) comprises the first NF node 10. That is, the first NF node 10 is deployed in Set 1 . A second set of NF nodes (“Set 2”) comprises the third NF node 20. That is, the third NF node 20 is deployed in Set 2. The CN comprises a single point of access (SPoA) 40 for the set of NFs comprising the first NF node 10, which is referred to herein as“Set 1 (SPoA)”. The CN also comprises a single point of access (SPoA) 50 for the set of NFs comprising the third NF node 20, which is referred to herein as“Set 2 (SPoA)”.

In Figure 15(a)-(b), Service C 70 receives an indication of a new destination (and, if required, a new resource Id) in an error response from Service A 18 of the first NF node 10.

Further details regarding each step of the signalling in Figure 15(a)-(b) are provided below:

Step 30 - The Service C 70, which has been using the context data transferred in the manner described earlier, sends an operation request to access that context data.

Step 31 - The operation may be routed via the Set 1 (SPoA) 40 in the manner described earlier in respect of various steps (e.g. Step 1 1 of Figure 12(a)-

(c)). Step 32 After execution of the service operation, if Service A 18 tries to modify the corresponding context data, it gets an error since the context data is protected (due to the write lock described earlier in respect of various steps, e.g. Step 14 of Figure 12(a)-(c)). The error response may be generated by the storage resource (or memory) 14. In the error response, the information of the alternative destination is included (Set 2). It may also include (e.g. when a resource is created in the manner described earlier in respect of various steps, such as Step 18 of Figure 12(a)-(c)), the context reference and/or the location (e.g. a reference to the newly created context in Set 2, such as the resource Id). The error response may be a HTTP response in some embodiments, e.g. a HTTP 4xx or 5xx status code.

Step 33 - The error response may be sent to Service C 70 via the Set 1 (SPoA) 40. Step 34 - The error response is received by Service C 70, including the information about the new destination set (Set 2) and optionally also the context reference and/or the location.

Step 35 - Service C 70 of the fourth NF node may update at least that, for this context data, the new destination is Set 2. Additionality, if the location is included, it may update local mapping, e.g. from general keys (such as SUPI, PDU, Session id, etc.) to the newly created resource.

Figure 16(a)-(b) is a signalling (or call flow) diagram illustrating an exchange of signals in an embodiment. The exchange of signals is in a CN, which comprises a first NF node 10, a third NF node 20, and a fourth NF node (not illustrated).

The first NF node 10 is as described earlier with reference to Figure 4 and the third NF node 20 is as described earlier with reference to Figure 7. The fourth NF node is as described earlier with reference to Figure 10 for the second NF node 30. The first NF node 10 is a provider of a first service (“Service A”) 18. The third NF node 20 is also a provider of (e.g. another instance of) Service A 28. The fourth NF node implements a third service 70 that is a consumer of Service A 18, 28. The third service will be referred to as“Service C” 70. In the CN illustrated in Figure 15(a)-(b), a first set of NF nodes (“Set 1”) comprises the first NF node 10. That is, the first NF node 10 is deployed in Set 1 . A second set of NF nodes (“Set 2”) comprises the third NF node 20. That is, the third NF node 20 is deployed in Set 2. The CN comprises a single point of access (SPoA) 40 for the set of NFs comprising the first NF node 10, which is referred to herein as“Set 1 (SPoA)”. The CN also comprises a single point of access (SPoA) 50 for the set of NFs comprising the third NF node 20, which is referred to herein as“Set 2 (SPoA)”.

In Figure 16(a)-(b), a redirection indication is provided. Further details regarding each step of the signalling in Figure 16(a)-(b) are provided below:

Step 31 - The operation may be routed via the Set 1 (SPoA) 40 in the manner described earlier in respect of various steps (e.g. Step 1 1 of Figure 12(a)-(c)). Step 32 - After execution of the service operation, if Service A 18 tries to modify the corresponding context data, it gets an error since the context data is protected (due to the write lock described earlier in respect of various steps, e.g. Step 14 of Figure 12(a)-(c)). The error response may be generated by the storage resource (or memory) 14. In the error response, the information of the alternative destination is included (Set 2). It may also include (e.g. when a resource is created in the manner described earlier in respect of various steps, such as Step 18 of Figure 12(a)-(c)), the context reference and/or the location (e.g. a reference to the newly created context in Set 2, such as the resource Id). Service A interprets the error and prepares a (e.g. permanent) redirection response, such as a HTTP 3xx status code (e.g. HTTP 301 ). This redirection response may include an identifier (e.g. URI or similar) pointing to the new destination (Set 2) and identifying the dynamic resource location, if required. Step 33 - The redirection response may be sent to Service C 70 via the Set 1 (SPoA) 40.

Step 34 - The redirection response is received by Service C 70, including the information about the new destination set (Set 2) and optionally also the context reference and/or the location.

Steps 36-37 - Service C 70 sends a request to the new destination in Set 2 and optionally also the location (e.g. Resource Id). That is, Service C 70 sends a request to the third NF node 20, e.g. via Set 2 (SPoA) 50.

Steps 38-41 - A similar method is performed to that described earlier with reference to Steps 5-8 of Figure 12(a)-(c).

In some embodiments, when combined with the embodiment illustrated in Figure 12(a)- (c) of Figure 13(a)-(b), it may be indicated in Step 25 of Figure 12(a)-(c) or Step 24 of Figure 13(a)-(b), that the redirection is the response in case of an attempt to modify the context data. In the above description, it has been considered that each operation related context data is transferred, step by step. This may not ensure whole NF node/service context data is transferred, and then Set 1 has to remain up and running in the network. However, if there is interest by the operation to decommission the full NF node/service, then a decision can be taken on what to do with any context data left (i.e. not transferred).

Some context data, e.g. after a certain time, may turn to be obsolete and it may not be subject to transfer any longer. This may depend on each service business logic. Some context data may not be obsolete, but it may be acceptable by the operator that, e.g. after some time, this context data is lost. This may ultimately require that a UE/subscriber may need to reconnect/re-register. This is a regular practice today and re-registration is assumed in some cases after some time. However, in case none of these possibilities is valid for some specific context, after some time, the context data may still need to be transferred.

Thus, the full decommissioning of the first NF node may be started after some time, e.g. by O&M. This is received in places indicated, e.g. in Step 9 of Figure 12(a)-(c). This requests full decommission of Service A. If the intention is to decommission a full NF, the request may be repeated for all the services in the NF. In this case, there may be an extra indication to remark this is a kind of“forced” transfer of context“leftovers”. Then, Service A may check the remaining context data in the storage resource (or memory) 14, i.e. the one that is not marked with a new location. For that context data, Service A may contact the context transfer service, which may then handle the decommissioning in any suitable manner.

Note that an alternative for this step exists. It relies on a“dummy” Service A operation being executed for the given context data. The intention is to transfer context data but, in this case, the service operation may not be executed. Then, a service operation can be marked with a new indication that it is “only for context data transfer”. This indicates, at reception by (Set 2) Service A, that only the context transfer actions are to be performed, not the service operation execution. That is, for example, the Step 20 in Figure 12(a)-(c) may not be executed. As mentioned, a new context transfer service may be used instead of Service A operation extension.

Figure 17 is a block diagram illustrating a first NF node 1 100 in accordance with an embodiment. The first NF node 1 100 comprises an initiating module 1 102 configured to, in response to a request from a second service of a second NF node for execution of a service operation of the first service, initiate a transfer of context data to a third NF node with a transfer of the service operation of the first service to the third NF node. The context data comprises data required for the service operation of the first service to be executed. The first NF node 1 100 may operate in the manner described herein.

Figure 18 is a block diagram illustrating a third NF node 1200 in accordance with an embodiment. The third NF node 1200 comprises an executing module 1202 configured to, in response to a first NF node initiating a transfer of context data to the third NF node 1200 with a transfer of a service operation of the first service to the third NF node 1200, execute the service operation of the first service using the context data. The context data comprises data required for the service operation of the first service to be executed. The transfer of context data is in response to a request from a second service of a second NF node for execution of the service operation of the first service. The third NF node 1200 may operate in the manner described herein.

Figure 19 is a block diagram illustrating a second NF node 1300 in accordance with an embodiment. The second NF node 1300 comprises an initiating module 1302 configured to, initiate a request from the second service of the second NF node 1300 for execution of a service operation of the first service to cause the initiation of a transfer of context data to a third NF node with a transfer of the service operation of the first service to the third NF node. The context data comprises data required for the service operation of the first service to be executed. The second NF node 1300 may operate in the manner described herein.

There is provided a computer program comprising instructions which, when executed by processing circuitry (such as the processing circuitry 12, 22, 32 of any of the NF nodes 10, 20, 30 described earlier), cause the processing circuitry to perform at least part of the method described herein. There is provided a computer program product, embodied on a non-transitory machine-readable medium, comprising instructions which are executable by processing circuitry (such as the processing circuitry 12, 22, 32 of any of the NF nodes 10, 20, 30 described earlier) to cause the processing circuitry to perform at least part of the method described herein. There is provided a computer program product comprising a carrier containing instructions for causing processing circuitry (such as the processing circuitry 12, 22, 32 of any of the NF nodes 10, 20, 30 described earlier) to perform at least part of the method described herein. In some embodiments, the carrier can be any one of an electronic signal, an optical signal, an electromagnetic signal, an electrical signal, a radio signal, a microwave signal, or a computer-readable storage medium.

The following numbered statements set out embodiments of the disclosure: 1. A method of operating a first network function, NF, node of a network for execution of a service operation, wherein the first NF node is a provider of a first service, the method comprising:

in response to a request from a second service of a second NF node for execution of a service operation of the first service:

initiating a transfer of context data to a third NF node with a transfer of the service operation of the first service to the third NF node,

wherein the context data comprises data required for the service operation of the first service to be executed.

2. A method according to embodiment 1 , wherein:

the first service of the first NF node is operable to perform the method.

3. A method according to any of the preceding embodiments, wherein:

the first NF node comprises an NF node of a first set of NF nodes.

4. A method according to any of the preceding embodiments, wherein:

the first service comprises a service of a first set of services.

5. A method according to any of the preceding embodiments, wherein:

the transfer of context data is initiated by the first service of the first NF node in response to information from an operation and maintenance procedure, O&M.

6. A method according to embodiment 5, wherein:

the information from the operation and maintenance procedure is indicative that load balancing is required to reduce the load of the first NF node.

7. A method according to any of embodiments 1 to 4, wherein:

the transfer of context data is initiated by the first service of the first NF node in response to an event at the first NF node or an event at another NF node of which the first NF node is informed.

8. A method according to embodiment 7, wherein:

the event at the first NF node or the event at another NF node comprises an event indicative of a load of the first NF node reaching a maximum threshold. 9. A method according to any of embodiments 1 to 4, wherein:

the request is initiated by the second service of the second NF node in response to information from an operation and maintenance procedure.

10. A method according to embodiment 9, wherein:

the information from the operation and maintenance procedure is indicative that load balancing is required to reduce the load of the first NF node. 1 1 . A method according to any of embodiments 1 to 4, wherein:

the request is initiated by the second service of the second NF node in response to an event at the second NF node.

12. A method according to embodiment 1 1 , wherein:

the event at the second NF node comprises an event indicative of a load of the first NF node reaching a maximum threshold.

13. A method according to any of the preceding embodiments, wherein:

the request comprises any one or more of:

an indication that the context data is to be transferred; and/or an indication of a set of network functions comprising the third NF node.

14. A method according to any of the preceding embodiments, wherein:

the request comprises an indication of a set of network functions comprising a NF node at which the context data is stored.

15. A method according to any of the preceding embodiments, wherein:

the service operation is transferred to the third NF node from the second service of the second NF node.

16. A method according to any of embodiments 1 to 14, wherein:

the service operation is transferred to the third NF node from the first service of the first NF node. 17. A method according to any of the preceding embodiments, wherein: the transfer of the context data to the third NF node is via a single point of access, SPoA, for a set of network functions comprising the third NF node.

18. A method according to any of the preceding embodiments, the method comprising:

identifying the context data prior to initiating the transfer of context data.

19. A method according to any of the preceding embodiments, the method comprising:

locking the context data prior to initiating the transfer of the context data.

20. A method according to any of the preceding embodiments, the method comprising:

adapting the context data to a standard format valid for the third NF node prior to initiating the transfer of the context data.

21 . A method according to any of the preceding embodiments, wherein:

the context data is acquired from a memory of the first NF node.

22. A method according to any of the preceding embodiments, the method comprising:

initiating a transfer of additional context data to the third NF node with the transfer of the context data, wherein the additional context data comprises data that is not required for the service operation of the first service to be executed.

23. A method according to embodiment 22, wherein:

the additional context data comprises data that is dependent on the context data and/or managed by the first service at the first NF node.

24. A method according to any of embodiments 22 to 23, the method comprising: identifying the additional context data prior to initiating the transfer of additional context data.

25. A method according to any of embodiments 22 to 24, the method comprising: locking the additional context data prior to initiating the transfer of the additional context data.

26. A method according to any of embodiments 22 to 25, the method comprising: adapting the additional context data to a standard format valid for the third NF node prior to initiating the transfer of the additional context data.

27. A method according to any of embodiments 22 to 26, wherein:

the additional context data is acquired from a memory of the first NF node.

28. A method according to any of the preceding embodiments, the method comprising:

receiving a response from the third NF node, wherein the response comprises an indication that subsequent execution of the service operation of the first service is to be performed by the third NF node.

29. A method according to embodiment 28, wherein:

the response further comprises an indication that identifies the third NF node.

30. A method according to embodiment 29, wherein:

the indication that identifies the third NF node comprises any one or more of: a uniform resource identifier, URI, for the third NF node;

a fully qualified domain name, FQDN, of the third NF node; and an Internet Protocol, IP, address of the third NF node.

31 . A method according to any of embodiments 28 to 30, the method comprising: storing the response in a memory of the first NF node.

32. A method according to any of embodiments 28 to 31 , the method comprising: updating the context data based on the response.

33. A method according to any of embodiments 28 to 32, the method comprising: initiating transmission of the response to the second NF node.

34. A method according to embodiment 33, wherein: the transmission of the response to the second NF node is via a single point of access, SPoA, for a set of network functions comprising the first NF node.

35. A method according to any of the preceding embodiments, the method comprising:

attempting to modify the context data; and

in response to the attempt to modify the context data, receiving an error response comprising an indication that an error occurred and/or an indication that subsequent execution of the service operation of the first service is to be performed by the third NF node.

36. A method according to embodiment 35, the method comprising:

initiating a transfer of the error response to a third service of a fourth NF node.

37. A method according to any of embodiments 35 to 36, the method comprising: generating a redirection response comprising an identifier pointing to the third NF node; and

initiating a transfer of the redirection response to a third service of a fourth NF node.

38. A first NF node configured to operate in accordance with any of embodiments 1 to 37.

39. A first NF node according to embodiment 38, wherein the first NF node comprises:

processing circuitry; and

at least one memory for storing instructions which, when executed by the processing circuitry, cause the first NF node to operate in accordance with any of embodiments 1 to 37.

40. A method of operating a third network function, NF, node of a network for execution of a service operation, wherein the third NF node is a provider of a first service, the method comprising:

in response to a first NF node initiating a transfer of context data to the third NF node with a transfer of a service operation of the first service to the third NF node: executing the service operation of the first service using the context data, wherein the context data comprises data required for the service operation of the first service to be executed,

wherein the transfer of context data is in response to a request from a second service of a second NF node for execution of the service operation of the first service.

41 . A method according to embodiment 40, wherein:

the first service of the third NF node is operable to perform the method.

42. A method according to any of the embodiments 40 to 41 , wherein:

the third NF node comprises an NF node of a second set of NF nodes.

43. A method according to any of embodiments 40 to 42, wherein:

the first service comprises a service of a first set of services.

44. A method according to any of embodiments 40 to 43, the method comprising: creating a resource to execute the service operation of the first service.

45. A method according to any of embodiments 40 to 44, the method comprising: storing the context data in a memory of the third NF node.

46. A method according to embodiment 45, wherein:

the context data is stored prior to the execution of the service operation of the first service.

47. A method according to any of embodiments 40 to 46, the method comprising: processing the context data to restore other data for use in executing the service operation of the first service.

48. A method according to any of embodiments 40 to 47, the method comprising: initiating a transfer, from the third NF node to one or more other NF nodes, wherein the transfer comprises a transfer of information and/or a request for actions to be performed to enable the one or more other NF nodes to manage changes in the network that result from the transfer of the context data to the third NF node. 49. A method according to any of embodiments 40 to 48, the method comprising: updating the context data following the execution of the service operation of the first service.

50. A method according to any of embodiments 40 to 49, the method comprising: initiating a transfer of a response to the first NF node,

wherein the response comprises an indication that subsequent execution of the service operation of the first service is to be performed by the third NF node.

51 . A method according to embodiment 50, wherein:

the response further comprises an indication that identifies the third NF node.

52. A method according to embodiment 51 , wherein:

a fully qualified domain name, FQDN, of the third NF node; and an Internet Protocol, IP, address of the third NF node. 53. A method according to any of embodiments 40 to 52, wherein:

the transfer of the response to the first NF node is via a single point of access, SPoA, for a set of network functions comprising the third NF node.

54. A third NF node configured to operate in accordance with any of embodiments 40 to 53.

55. A third NF node according to embodiment 54, wherein the third NF node comprises:

processing circuitry; and

at least one memory for storing instructions which, when executed by the processing circuitry, cause the third NF node to operate in accordance with any of embodiments 40 to 53. 56. A method of operating a second network function, NF, node of a network for execution of a service operation, wherein the second NF node implements a second service that is a consumer of a first service, the method comprising:

initiating a request for execution of a service operation of the first service to cause the initiation of a transfer of context data to a third NF node with a transfer of the service operation of the first service to the third NF node,

57. A method according to embodiment 56, wherein:

the second service of the second NF node is operable to perform the method.

58. A method according to any of embodiments 56 to 57, wherein:

the second NF node comprises an NF node of a third set of NF nodes.

59. A method according to any of embodiments 56 to 58, wherein:

the second service comprises a service of a third set of services.

60. A method according to any of embodiments 56 to 59, wherein:

the request is initiated in response to information from an operation and maintenance procedure.

61 . A method according to embodiment 60, wherein:

62. A method according to any of embodiments 56 to 59, wherein:

the request is initiated in response to an event at the second NF node.

63. A method according to embodiment 62, wherein:

64. A method according to any of embodiments 56 to 63, the method comprising: transferring the service operation to the third NF node from the third service of the NF node.

65. A method according to any of embodiments 56 to 64, the method comprising: receiving a response from the first NF node or from a single point of access,

SPoA, for a set of network functions comprising the third NF node,

66. A method according to embodiment 65, wherein:

the response further comprises an indication that identifies the third NF node.

67. A method according to embodiment 66, wherein:

68. A method according to any of embodiments 65 to 67, wherein:

the receipt of the response from the first NF node is via a single point of access, SPoA, for a set of network functions comprising the first NF node.

69. A second NF node configured to operate in accordance with any of embodiments 56 to 68.

70. A second NF node according to embodiment 69, wherein the second NF node comprises:

processing circuitry; and

at least one memory for storing instructions which, when executed by the processing circuitry, cause the second NF node to operate in accordance with any of embodiments 56 to 68.

71 . A computer program comprising instructions which, when executed by processing circuitry, cause the processing circuitry to perform the method according to any of embodiments 1 to 37, 40 to 53, or 56 to 68. 72. A computer program product, embodied on a non-transitory machine-readable medium, comprising instructions which are executable by processing circuitry to cause the processing circuitry to perform the method according to any of embodiments 1 to 37, 40 to 53, or 56 to 68.

The NF node functionality described herein can be performed by hardware. Thus, any one or more of the NF nodes described herein can be a hardware NF node. However, it will also be understood that at least part or all of the NF node functionality described herein can be virtualized. For example, the functions performed by any one or more of the NF nodes can be implemented in software running on generic hardware that is configured to orchestrate the system functionality. Thus, in some embodiments, any one or more of the NF nodes can be a virtual NF node. In some embodiments, at least part or all of the NF node functionality described herein may be performed in a network enabled cloud. The NF node functionality described herein may all be at the same location or at least some of the NF node functionality may be distributed.

Any one or more NF nodes (e.g. of a set of NF nodes) and/or any one or more services (e.g. of a set of services) may be operable to perform any of the methods described herein. It will be understood that at least some or all of the method steps described herein can be automated in some embodiments. That is, in some embodiments, at least some or all of the method steps described herein can be performed automatically.

Thus, in the manner described herein, there is advantageously provided an improved technique for use in executing a service operation. The separation of service logic and data in the manner described herein facilitates applying cloud-native design principles for services in the SBA domain. This improved technique described herein provides a mechanism to transfer context data between two sets (or NF/service instances) per service operation request, by both executing the operation, and transferring context data related to this operation.

There technique described is used to transfer context data from one service (Service A of the first NF node 10 of Set 1 ) to another service of the same type (Service A of the third NF node 20 of Set 2), which may be by same or different vendor. The technique can be enabled/activated by an indication either from O&M or other service/NF, or internal to the service (by an event, e.g. identification of load limits in the producer). The service that initiates the context data transfer may be Service B of the second NF node 30 or Service A of the first NF node 10 of Set 1 itself. The context transfer can be performed upon a service operation request from Service B of the second NF node 30, which can then result in both the execution of the service operation and the transfer of the context data required for the service operation to be executed and any additional context data (e.g. all dependent context data may be transferred at once). At least one of the service operations may be extended to include an indication of the context data transfer being requested and, based on that indication, the technique may provide the means for the operation to be executed in the alternative service (Service A of the third NF set 20 of Set 2), including the context data to be transferred.

The technique can apply to context data to be transferred between services belonging to an NF node (or instance), services where the NF nodes (or instances) may be organized in NF sets, services deployed as individual service instance, and services that are part of a service set. The technique may apply to cases where the services are organized in different constructs, such as individual NF nodes (or instances), or other independent constructs that may be defined in the future, such as individual independent services or service sets.

The technique allows for a context data transfer when that context data is to be accessed by a service operation execution, i.e. when a service operation is to be executed. This implies that the extra processing and signalling that context data transfer requires is per user activity (per service operation request), which avoids overloading and/or extra dimensioning and/or the need to plan the execution of the context data transfer during low peak hours. It also allows resource utilization balancing by moving resources from Set 1 to Set 2. The technique provides the means to transfer context data by an extension of the service operations, with no need for the creation of a new service and/or operations. It should be noted that the above-mentioned embodiments illustrate rather than limit the idea, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. The word “comprising” does not exclude the presence of elements or steps other than those listed in a claim,“a” or“an” does not exclude a plurality, and a single processor or other unit may fulfil the functions of several units recited in the claims. Any reference signs in the claims shall not be construed so as to limit their scope.

Claims

1. A method of operating a first network function, NF, node (10) for execution of a service operation, wherein the first NF node (10) is a provider of a first service (18), the method comprising:

in response to a request from a second service (38) of a second NF node (30) for execution of a service operation of the first service:

initiating (100) a transfer of context data to a third NF node (20) with a transfer of the service operation of the first service to the third NF node (20), wherein the context data comprises data required for the service operation of the first service to be executed.

2. A method according to claim 1 , wherein:

the transfer of context data is initiated by:

the first service (18) of the first NF node (10) in response to information from an operation and maintenance procedure; and/or

the first service (18) of the first NF node (10) in response to an event at the first NF node (10) or an event at another NF node of which the first NF node (10) is informed.

3. A method according to claim 2, wherein:

the information from the operation and maintenance procedure is indicative that load balancing is required to reduce the load of the first NF node (10); and

the event is indicative of a load of the first NF node (10) reaching a maximum threshold.

4. A method according to any of the preceding claims, the method comprising: identifying the context data prior to initiating the transfer of context data;

locking the context data prior to initiating the transfer of the context data; and/or adapting the context data to a standard format valid for the third NF node (20) prior to initiating the transfer of the context data.

5. A method according to any of the preceding claims, the method comprising: initiating a transfer of additional context data to the third NF node (20) with the transfer of the context data, wherein the additional context data comprises data that is not required for the service operation of the first service to be executed.

6. A method according to any of the preceding claims, the method comprising: receiving a response from the third NF node (20), wherein the response comprises an indication that subsequent execution of the service operation of the first service is to be performed by the third NF node (20) and/or an indication that identifies the third NF node (20).

7. A first NF node (10) configured to operate in accordance with any of claims 1 to 6.

8. A first NF node (10) according to claim 7, wherein the first NF node comprises: processing circuitry (12); and

at least one memory (14) for storing instructions which, when executed by the processing circuitry (12), cause the first NF node (10) to operate in accordance with any of claims 1 to 6.

9. A method of operating a third network function, NF, node (20) for execution of a service operation, wherein the third NF node (20) is a provider of a first service (28), the method comprising:

in response to a first NF node (10) initiating a transfer of context data to the third NF node (20) with a transfer of a service operation of the first service (28) to the third NF node (20):

executing the service operation of the first service using the context data, wherein the context data comprises data required for the service operation of the first service to be executed,

wherein the transfer of context data is in response to a request from a second service of a second NF node (30) for execution of the service operation of the first service.

10. A method according to claim 9, the method comprising:

creating a resource to execute the service operation of the first service;

storing the context data in a memory of the third NF node (20); processing the context data to restore other data for use in executing the service operation of the first service; and/or

updating the context data following the execution of the service operation of the first service.

1 1 . A method according to any of claims 9 to 10, the method comprising:

initiating a transfer of a response to the first NF node (10),

wherein the response comprises an indication that subsequent execution of the service operation of the first service is to be performed by the third NF node (20) and/or an indication that identifies the third NF node (20).

12. A third NF node (20) configured to operate in accordance with any of claims 9 to 1 1 .

13. A third NF node (20) according to claim 12, wherein the third NF node comprises: processing circuitry (22); and

at least one memory (24) for storing instructions which, when executed by the processing circuitry (22), cause the third NF node (20) to operate in accordance with any of claims 9 to 1 1.

14. A method of operating a second network function, NF, node (30) for execution of a service operation, wherein the second NF node (30) implements a second service (38) that is a consumer of a first service (18), the method comprising:

initiating a request for execution of a service operation of the first service to cause the initiation of a transfer of context data to a third NF node (20) with a transfer of the service operation of the first service to the third NF node (20),

15. A method according to claim 14, wherein:

the request is initiated in response to information from an operation and maintenance procedure; or

the request is initiated in response to an event at the second NF node (30).

16. A method according to any of claims 14 to 15, the method comprising: receiving a response from the first NF node (10) or from a single point of access, SPoA (50), for a set of network functions comprising the third NF node (20),

wherein the response comprises an indication that subsequent execution of the service operation of the first service is to be performed by the third NF node (20).

17. A second NF node (30) configured to operate in accordance with any of claims 14 to 16.

18. A second NF node (30) according to claim 17, wherein the second NF node comprises:

processing circuitry (32); and

at least one memory (34) for storing instructions which, when executed by the processing circuitry (32), cause the second NF node (30) to operate in accordance with any of claims 14 to 16.

19. A computer program comprising instructions which, when executed by processing circuitry, cause the processing circuitry to perform the method according to any of claims 1 to 6, 9 to 1 1 , or 14 to 16.

20. A computer program product, embodied on a non-transitory machine-readable medium, comprising instructions which are executable by processing circuitry to cause the processing circuitry to perform the method according to any of claims 1 to 6, 9 to 1 1 , or 14 to 16.