[Conditional] AMF to SMF: Nsmf_PDUSession_UpdateSMContext ().
For an Emergency Registered UE, this step is applied when the Registration Type is Mobility Registration Update.
The AMF invokes the Nsmf_PDUSession_UpdateSMContext (see clause 188.8.131.52.6
) in the following scenario(s):
If the List Of PDU Sessions To Be Activated is included in the Registration Request in step 1, the AMF sends Nsmf_PDUSession_UpdateSMContext Request to SMF(s) associated with the PDU Session(s) in order to activate User Plane connections of these PDU Session(s). Steps from step 5 onwards described in clause 184.108.40.206 are executed to complete the User Plane connection activation without sending the RRC Inactive Assistance Information and without sending MM NAS Service Accept from the AMF to (R)AN described in step 12 of clause 220.127.116.11.
When the serving AMF has changed, the new serving AMF notifies the SMF for each PDU Session that it has taken over the responsibility of the signalling path towards the UE: the new serving AMF invokes the Nsmf_PDUSession_UpdateSMContext service operation using SMF information received from the old AMF at step 5. It also indicates whether the PDU Session is to be re-activated. In the case of PLMN change from V-PLMN to H-PLMN, the new serving AMF only invokes the Nsmf_PDUSession_UpdateSMContext service operation for Home Routed PDU session(s).
NOTE 7: If the UE moves into a V-PLMN, the AMF in the V-PLMN can not insert or change the V-SMF(s) even for Home Routed PDU session(s).
Steps from step 5 onwards described in clause 18.104.22.168 are executed. In the case that the intermediate UPF insertion, removal, or change is performed for the PDU Session(s) not included in "PDU Session(s) to be re-activated", the procedure is performed without N11 and N2 interactions to update the N3 user plane between (R)AN and 5GC.
The AMF invokes the Nsmf_PDUSession_ReleaseSMContext service operation towards the SMF in the following scenario:
If any PDU Session status indicates that it is released at the UE, the AMF invokes the Nsmf_PDUSession_ReleaseSMContext service operation towards the SMF in order to release any network resources related to the PDU Session.
If the serving AMF is changed, the new AMF shall wait until step 18 is finished with all the SMFs associated with the UE. Otherwise, steps 19 to 22 can continue in parallel to this step.