5.5.2.2.7 Abnormal cases in the network side

The following abnormal cases can be identified:

• De-registration request received in a cell belonging to an SNPN with a non-globally-unique SNPN identity for which the UE has no valid subscription

If the UE initiates a de-registration procedure in a cell belonging to an SNPN with a non-globally-unique SNPN identity for which the UE has no valid subscription, and the de-registration procedure is not due to "switch off", the network shall initiate the de-registration procedure. The AMF shall send a DEREGISTRATION REQUEST message including the 5GMM cause #74 "Temporarily not authorized for this SNPN".

• De-registration request received in a cell belonging to an SNPN with a globally-unique SNPN identity for which the UE has no valid subscription

If the UE initiates a de-registration procedure in a cell belonging to an SNPN with a globally-unique SNPN identity for which the UE has no valid subscription, and the de-registration procedure is not due to "switch off", the network shall initiate the de-registration procedure. The AMF shall send a DEREGISTRATION REQUEST message including the 5GMM cause #75 "Permanently not authorized for this SNPN".

• De-registration request received in a CAG cell and none of the CAG ID broadcasted by the CAG cell is authorized based on the UE's "allowed CAG list" for the current PLMN

If the UE initiates a de-registration procedure in a CAG cell and none of the CAG ID broadcasted by the CAG cell is authorized based on the UE's "allowed CAG list" for the current PLMN and the de-registration procedure is not due to "switch off", the AMF shall initiate the de-registration procedure. The AMF shall send a DEREGISTRATION REQUEST message including the 5GMM cause #76 "Not authorized for this CAG or authorized for CAG cells only" if the UE supports CAG. Otherwise, the network shall operate as described in bullet g) of clause 5.5.2.3.5.

• De-registration request received in a non-CAG cell from a UE whose "CAG information list" includes an entry associated with the current PLMN, where the entry contains an "indication that the UE is only allowed to access 5GS via CAG cells"

If the UE initiates a de-registration procedure in a non-CAG cell from a UE whose "CAG information list" includes an entry associated with the current PLMN, where the entry contains an "indication that the UE is only allowed to access 5GS via CAG cells" and the de-registration procedure is not due to "switch off", the AMF shall initiate the de-registration procedure. The AMF shall send a DEREGISTRATION REQUEST message including the 5GMM cause #76 "Not authorized for this CAG or authorized for CAG cells only" if the UE supports CAG. Otherwise, the network shall operate as described in bullet g) of clause 5.5.2.3.5.

• De-registration and registration procedure for initial registration collision

If the network receives a REGISTRATION REQUEST message indicating either "initial registration" or "emergency registration" in the 5GS registration type IE from the UE before the UE-initiated de-registration procedure, which is not due to switch off, has been completed, the network shall abort the de-registration procedure and the registration procedure shall be progressed.

• Lower layers indication of non-delivered NAS PDU due to handover.

If the DEREGISTRATION ACCEPT message could not be delivered due to an intra AMF handover and the target TA is included in the TAI list, then upon successful completion of the intra AMF handover the AMF shall retransmit the DEREGISTRATION ACCEPT message. If a failure of handover procedure is reported by the lower layer and the N1 NAS signalling connection exists, the AMF shall retransmit the DEREGISTRATION ACCEPT message.