4.7.2.1 General

The mobility management procedures defined over 3GPP access are re-used over non-3GPP access with the following exceptions:

• the registration status, and the 5GMM parameters of the UE's 3GPP access and non-3GPP access 5GMM state machine instances are independent in each of these accesses and can be different;
• single-registration mode and dual-registration mode do not apply for 5GMM over non-3GPP access;
• the RPLMN over non-3GPP access can be different from the RPLMN over 3GPP access. The MCC of the RPLMN over 3GPP access and the MCC of the RPLMN over the non-3GPP access can also be different;
• the registration for 3GPP access and for non-3GPP access are performed separately. Like for 3GPP access, an access stratum connection exists before the UE can perform the registration procedure for non-3GPP access. As at registration over non-3GPP access the UE is allocated a registration area, which is associated with a single TAI, list management of registration areas is not required, and registration updating due to registration area change with the registered PLMN is not performed. Furthermore, the registration procedure for periodic registration update is also not performed. New registration at change of PLMN is required;
• the 5GMM over non-3GPP access in the UE considers that the N1 NAS signalling connection is established when the lower layers indicate that the access stratum connection is established succcessfully;
• the UE-initiated service request procedure via non-3GPP access is supported. Upon indication from the lower layers of non-3GPP access, that the access stratum connection is established between the UE and the network, the UE in 5GMM-REGISTERED state and in 5GMM-IDLE mode over non-3GPP access shall initiate the service request procedure via non-3GPP access. The UE may indicate with the service request message the PDU session(s) associated with non-3GPP access to re-establish user-plane resources for which the UE has pending user data to be sent;
• paging procedure is not performed via non-3GPP access;
• service area restrictions do not apply for non-3GPP access other than the wireline access;
• the establishment cause for non-3GPP access is determined according to clause 4.7.2.2;
• eCall inactivity procedure is not performed via non-3GPP access;
• local area data network (LADN) does not apply for non-3GPP access;
• the Allowed PDU session status IE shall not be included in the REGISTRATION REQUEST message or the SERVICE REQUEST message sent over non-3GPP access;
• DRX parameters do not apply for non-3GPP access;
• Mobile initiated connection only mode (MICO) does not apply for non-3GPP access;
• CIoT 5GS optimizations do not apply for non-3GPP access;
• unified access control does not apply for non-3GPP access;
• UE radio capability signalling optimisation (RACS) does not apply for non-3GPP access;
• Closed access group (CAG) does not apply for non-3GPP access;
• the N1 NAS signalling connection release, the paging indication for voice services and reject the paging request do not apply for non-3GPP access. The Paging restriction IE shall not be included in the REGISTRATION REQUEST message, the SERVICE REQUEST message or the CONTROL PLANE SERVICE REQUEST message sent over non-3GPP access. The AMF shall not delete any stored paging restriction preferences for the UE and shall not stop restricting paging when receiving REGISTRATION REQUEST message, SERVICE REQUEST message or CONTROL PLANE SERVICE REQUEST message over non-3GPP access;
• the partially allowed NSSAI and the partially rejected NSSAI do not apply for non-3GPP access;
• support for unavailability period (see clause 5.3.26) does not apply for non-3GPP access;
• disaster roaming services (see clause 4.24) do not apply for non-3GPP access; and
• access technology utilization control does not apply for non-3GPP access.

If there is an ongoing procedure over non-3GPP access and there is a trigger for an emergency call from upper layers, the UE shall abort the ongoing procedure over non-3GPP access, and utilize the procedures specified in 3GPP TS 23.167 [6] and 3GPP TS 24.229 [14] to select a domain for the emergency session attempt over 3GPP access.