Section: 4.25.7 SMF Initiated SMF-NEF Connection Release procedure
Content: When the PDU Session Release is initiated and if a NEF has been selected as anchor of the Control Plane CIoT 5GS Optimisation enabled PDU session which is Unstructured PDU Session Type as described in clause 4.3.4.2, then the SMF initiates a SMF-NEF Connection Release procedure towards the NEF corresponding to the "NEF ID" for that DNN / S-NSSAI Combination. Figure 4.25.7-1: SMF Initiated SMF-NEF Connection Release procedure 1. The SMF performs Step 1 of PDU Session Release Procedure as described in clause 4.3.4.2. 2. If a NEF has been selected as anchor of the Control Plane CIoT 5GS Optimisation enabled PDU session which is Unstructured PDU Session Type as described in clause 4.3.2.2, the SMF initiates the SMF-NEF Connection release for this PDU Session by sending Nnef_SMContext_Delete Request (User Identity, PDU Session ID, S-NSSAI, DNN, Release Cause) message to the NEF. 3. The NEF deletes the NEF PDU Session Context associated with the User Identity and the PDU session ID. The NEF sends Nnef_SMContext_Delete Response (Cause, [Small Data Control Rate Status], [APN Rate Control Status]) to the SMF confirming release of the SMF-NEF session for the UE. The NEF includes Small Data Rate Control Status if PDU Session used Small Data Rate Control. 4. Steps 3-15 of PDU Session Release Procedure as described in clause 4.3.4.2.