Apparatus, methods, and computer programs

1. A network apparatus for a network function, the network apparatus comprising: at least one processor; and at least one memory comprising code of a service communication proxy that, when executed by the at least one processor, causes the network apparatus to perform:

in response to receiving a request from a network function service consumer, discovering a plurality of network function service instances configured for providing one or more services and determining a first network function service instance configured for providing the one or more services to the network function service consumer;

determining a second network function service instance, wherein the second network function service instance is an alternative or backup network function service instance configured to provide the one or more services to the network function service consumer; and

sending a response to the request to the network function service consumer, the response comprising an identity of the second network function service instance.

2. A The network apparatus as claimed in claim 1 , wherein the discovering comprises;

sending, to a network repository function, a discovery request for discovering the plurality of network function service instances; and

receiving, from the network repository function, the identity of the first network function service instance, the identity of the second network function service instance, and an indication that the second network function service instance is an alternative to the first network function service instance.

3. The network apparatus as claimed in claim 1 , wherein the first network function service instance comprises at least a first charging function instance, and the second network function service instance comprises at least a second charging function instance, and the one or more services comprises a charging service.

4. The network apparatus as claimed in claim 3 , the code, when executed by the at least one processor, further causes the network apparatus to perform:

sending a charging request for said charging service to the first charging function instance; and

receiving, from the first charging function instance, the identity of the second charging function instance, and an indication that the second charging function instance is an alternative charging function instance for the charging service.

5. A The network apparatus as claimed in claim 1 , wherein the code, when executed by the at least one processor, further causes the network apparatus to:

inserting the identity of the second network function service instance into a header of a message; and

sending the message to the network function service consumer.

6. The network apparatus as claimed in claim 5 , wherein the second network function service instance is explicitly indicated as being a backup network function service instance to the first network function service instance in said header.

7. The network apparatus as claimed in claim 5 , wherein said message is a charging data response received from a first charging function instance.

8. A network apparatus, the network apparatus comprising: at least one processor; and at least one memory comprising code of a network function service consumer that, when executed by the at least one processor, causes the network apparatus to perform:

sending a request to a service communication proxy for selecting a first network function service instance, the first network function service instance configured to provide one or more services to a network function service consumer;

receiving, in response to said request, an identity of a second network function service instance, wherein the second network function service instance is an alternative or backup network function service instance configured to provide the one or more services to the network function service consumer.

9. The network apparatus as claimed in claim 8 , wherein said identity of the first network function service instance and the identity of a second network function instance are comprised within a header of the response to said request.

10. The network apparatus as claimed in claim 9 , wherein the second network function service instance is explicitly indicated as being a backup network function service instance to the first network function service instance in said header.

11. The network apparatus as claimed in claim 8 , wherein the code, when executed by the at least one processor further causes the network apparatus to perform:

receive an indication that the first network function service instance is unable to provide the one or more services to the network function service consumer; and

in response to receiving said indication, directing at least one future request for the one or more services to the second network function service instance.

12. The network apparatus as claimed in claim 8 , wherein the first network function service instance comprises at least a first charging function instance, the second network function-service instance comprises a second charging function instance, and the one or more services comprise a charging service.

13. A method for a network apparatus comprising a service communication proxy, the method comprising:

in response to receiving a request from a network function service consumer, discovering a plurality of network function service instances configured for providing one or more services and determining a first network function service instance configured for providing the one or more services to the network function service consumer;

determining a second network function service instance, wherein the second network function service instance is an alternative or backup network function service instance configured to provide the one or more services to the network function service consumer; and

sending a response to the request to the network function service consumer, the response comprising with an identity of the second network function service instance.

14. The method as claimed in claim 13 , wherein the discovering comprises:

sending, to a network repository function, a discovery request for discovering the plurality of network function service instances; and

receiving, from the network repository function, the identity of the first network function service instance, the identity of the second network function service instance, and an indication that the second network function service instance is an alternative to the first network function service instance.

15. The method as claimed in claim 13 , wherein the first network function service instance comprises a first charging function instance, and a second network service function comprises first and a second charging function instance, and the one or more services comprises a charging service.

16. The method as claimed in claim 15 , further comprising:

sending a charging request for said charging service to the first charging function instance; and

receiving, from the first charging function instance, the identity of the second charging function instance, and an indication that the second charging function instance is an alternative charging function instance for providing the charging service.

17. The method as claimed in claim 13 , further comprising:

inserting the identity of the second network function service instance into a header of a message; and

sending the message to the network function service consumer.

18. A method as claimed in claim 17 , wherein the second network function service instance is explicitly indicated as being a backup network function service instance to the first network function service instance in said header.

19. The method as claimed in claim 17 , wherein said message is a charging data response received from first charging function instance.