5.5.2.2.3 UE-initiated de-registration procedure completion for 5GS services over 3GPP access

If the access type in the DEREGISTRATION REQUEST message indicates that the de-registration procedure is for 3GPP access, the AMF shall trigger the SMF to perform a local release of the PDU session(s) established over 3GPP access, if any, for this UE. The UE shall perform a local release of the PDU session(s) established over 3GPP access, if any. If a PDU session is associated with one or more multicast MBS sessions, the UE shall locally leave the associated multicast MBS sessions and the SMF shall consider the UE as removed from the associated multicast MBS sessions. If there is an MA PDU session with user plane resources established on both 3GPP access and non-3GPP access in the same PLMN or in different PLMNs, the AMF shall trigger SMF to perform release of user plane resources on 3GPP access, and the UE shall consider the user plane resources on 3GPP access as released. If there is an MA PDU session with user plane resources established on 3GPP access only, the AMF shall trigger the SMF to perform a local release of the MA PDU session, and the UE shall perform a local release of the MA PDU session. If the MA PDU session is associated with one or more MBS multicast sessions, the UE shall locally leave the associated MBS multicast sessions. The UE is marked as inactive in the AMF for 5GS services for 3GPP access. The AMF shall enter the state 5GMM-DEREGISTERED for 3GPP access.

If the UE supports N1 mode only and the de-registration request is not due to switch off, then:

• if the de-registration procedure was performed due to disabling of 5GS services, then the UE shall enter the 5GMM-NULL state for 3GPP access;
• otherwise, the UE shall enter the 5GMM-DEREGISTERED state for 3GPP access.

NOTE: Case b) is applicable when the UE is also registered over non-3GPP access.

If the access type indicates that the de-registration procedure is for 3GPP access or for 3GPP access and non-3GPP access, and the UE is operating in single-registration mode, it shall additionally proceed as specified in 3GPP TS 24.301 [15], clause 5.5.2.2.2, for the case when the UE receives an EMM message DETACH ACCEPT.

Furthermore, if the UE supports A/Gb or Iu mode and the de-registration procedure was not performed:

• due to the last running Tsor-cm timer expired or was stopped (see 3GPP TS 23.122 [5]) clause C.4.2);
• as part of eCall inactivity procedure;or
• due to switch off;

the UE shall disable the N1 mode capability for 3GPP access.