Release of a second session of a wireless device by an access and mobility management function

1. A method comprising:

receiving, by a target access and mobility management function (AMF) from a source AMF, a first message indicating:

a handover of a wireless device; and

a source session management function (SMF);

sending, by the target AMF to the source AMF, a second message causing a release of at least one second session of the wireless device; and

receiving, by the target AMF from the source AMF, a first indication of the completion of the release of the at least one second session.

2. The method of claim 1 , wherein the first message comprises at least one of:

an identity of the source SMF; or

an address of the source SMF.

3. The method of claim 1 , further comprising:

sending, by the target AMF to the source AMF, a response message for the first message, the response message indicating a forward relocation response for the wireless device.

4. The method of claim 1 , further comprising:

selecting, by the target AMF and in response to the handover, a target SMF different from the source SMF; and

sending, to the target SMF, a third message indicating creation of at least one first session, the third message comprising at least one session identifier of the at least one first session.

5. The method of claim 4 , wherein the third message further comprises at least one of:

a single network slice selection assistance information;

a network slicing instance identifier;

a data network name; or

a user identity of the wireless device.

6. The method of claim 4 , wherein the first message further:

indicates establishment of the at least one first session; and

comprises at least one of:

the at least one session identifier of the at least one first session;

a first Internet protocol (IP) address of the wireless device; or

a data network name.

7. The method of claim 4 , further comprising:

selecting, by the target AMF, a target user plane function (UPF) different from a source UPF; and

sending, to the target UPF, a fourth message requesting establishment of a session context for the at least one first session.

8. The method of claim 7 , wherein the target SMF receives, from the target UPF, a fifth message acknowledging establishment of the session context.

9. A target access and mobility management function (AMF) comprising:

one or more processors;

memory storing instructions that, when executed by the one or more processors, cause the target AMF to perform operations comprising:

receiving, from a source AMF, a first message indicating:

a handover of a wireless device; and

a source session management function (SMF);

sending, to the source AMF, a second message causing a release of at least one second session of the wireless device; and

receiving, from the source AMF, a first indication of the completion of the release of the at least one second session.

10. The target AMF of claim 9 , wherein the first message comprises at least one of:

an identity of the source SMF; or

an address of the source SMF.

11. The target AMF of claim 9 , wherein the operations further comprise:

sending, to the source AMF, a response message for the first message, the response message indicating a forward relocation response for the wireless device.

12. The target AMF of claim 9 , wherein the operations further comprise:

selecting, in response to the handover, a target SMF different from the source SMF; and

sending, to the target SMF, a third message indicating creation of at least one first session, the third message comprising at least one session identifier of the at least one first session.

13. The target AMF of claim 12 , wherein the third message further comprises at least one of:

a single network slice selection assistance information;

a network slicing instance identifier;

a data network name; or

a user identity of the wireless device.

14. The target AMF of claim 12 , wherein the first message further:

indicates establishment of the at least one first session; and

comprises at least one of:

the at least one session identifier of the at least one first session;

a first Internet protocol (IP) address of the wireless device; or

a data network name.

15. The target AMF of claim 12 , wherein the operations further comprise:

selecting a target user plane function (UPF) different from a source UPF; and

sending, to the target UPF, a fourth message requesting establishment of a session context for the at least one first session.

16. The target AMF of claim 15 , wherein the target SMF receives, from the target UPF, a fifth message acknowledging establishment of the session context.

17. A non-transitory computer-readable medium comprising instructions that, when executed by one or more processors, cause a target access and mobility management function (AMF) to perform operations comprising:

receiving, from a source AMF, a first message indicating:

a handover of a wireless device; and

a source session management function (SMF);

sending, to the source AMF, a second message causing a release of at least one second session of the wireless device; and

receiving, from the source AMF, a first indication of the completion of the release of the at least one second session.

18. The non-transitory computer-readable medium of claim 17 , wherein the first message comprises at least one of:

an identity of the source SMF; or

an address of the source SMF.

19. The non-transitory computer-readable medium of claim 17 , wherein the operations further comprise:

sending, to the source AMF, a response message for the first message, the response message indicating a forward relocation response for the wireless device.

20. The non-transitory computer-readable medium of claim 17 , wherein the operations further comprise:

selecting, in response to the handover, a target SMF different from the source SMF; and

sending, to the target SMF, a third message indicating creation of at least one first session, the third message comprising at least one session identifier of the at least one first session.