Efficient handling of subscriptions

1. A method in a second node, comprising:

receiving, from a first node, a first message, wherein said first message is a request for a subscription;

sending, to said first node, a second message, wherein said second message comprises a subscription ID for the subscription and an initial subscription validity time;

receiving, from said first node, a third message, wherein said third message comprises a new subscription validity time for said subscription; and

accepting an extension of the subscription validity time and sending a fourth message in response to said third message, wherein said fourth message indicates an updated subscription validity time for said subscription that is different than the initial subscription validity time.

2. The method of claim 1 , wherein said updated subscription validity time for said subscription is different than the validity time period indicated by said new validity time.

3. The method of claim 1 , wherein said fourth message is an HTTP 200 OK message comprising subscription data.

4. The method of claim 3 , wherein said subscription data comprises one or more of said updated time period, said subscription ID, and a subscription type.

5. The method of claim 1 , further comprising:

receiving, from a third node, a fifth message, wherein said fifth message is a registration message; and

sending, to said third node, a sixth message, wherein said sixth message indicates a registration status.

6. The method of claim 5 , wherein said second node is a Network Repository Function, NRF, said first node is a NF Service Consumer, and said third node is a NF Service Producer.

7. The method of claim 1 , wherein said first message comprises input criteria, wherein said input criteria comprise one or more of an event type, an instance identifier corresponding to said second node, or a set of conditions identifying one or more network functions for said subscription.

8. The method of claim 7 , wherein said first message is an HTTP POST message and said input criteria are in the form of a JSON document contained in the body of said HTTP POST message.

9. The method of claim 7 ,

wherein said event type comprises one or more of register, de-register, or profile change, or

wherein said set of conditions comprises one or of more network functions, NF, of a given type, all NFs supporting a given service, or all NFs belonging to a common set or group ID.

10. The method of claim 1 , further comprising:

generating said subscription ID; and

determining said initial subscription validity time.

11. The method of claim 1 , wherein said second message is an HTTP 201 message indicating that said first node has been successfully subscribed in accordance with said request for subscription.

12. The method of claim 1 , wherein said third message is an HTTP PATCH message.

13. The method of claim 1 , wherein said fourth message is an HTTP 204 No Content message.

14. A method in a first node, comprising: sending to a second node, a first message, wherein said first message is a request for a subscription;

receiving, from said second node, a second message, wherein said second message comprises a subscription ID for the subscription and an initial subscription validity time;

sending, to said second node, a third message, wherein said third message comprises a requested new validity time for said subscription; and

receiving a fourth message, wherein said fourth message indicates an updated validity time period for said subscription that is different than the initial subscription validity time.

15. The method of claim 14 , wherein

said updated validity time period for said subscription is different than the validity time indicated by said requested new validity time, and

said fourth message is an HTTP 200 message comprising subscription data, wherein said subscription data comprises one or more of said updated time period, said subscription ID, and a subscription type.

16. The method of claim 14 , wherein said first message comprises input criteria, wherein said input criteria comprise one or more of an event type, an instance identifier corresponding to said second node, and a set of conditions identifying one or more network functions for said subscription, wherein

said first message is an HTTP POST message and said input criteria are in the form of a JSON document contained in the body said HTTP POST message, or

said event type comprises one or more of register, de-register, and profile change, or

said set of conditions comprises one or more of network functions, NF, of a given type, all NFs supporting a given service, or all NFs belonging to a common set or group ID.

17. The method of claim 14 , wherein said second node is a Network Repository Function, NRF, said first node an NF Service Consumer, and said subscription relates to services provided by an NF Service Producer.

18. The method of claim 14 , further comprising:

determining the new subscription validity time.

19. The method of claim 14 , wherein said second message is an HTTP 201 message indicating successful subscription in accordance with said request for subscription, or said third message is an HTTP PATCH message.

20. The method of claim 14 , wherein said fourth message is an HTTP 204 No Content message.