5.5.3.1 UE reachability in CM-IDLE

This clause applies to Non-3GPP access network corresponding to the Untrusted Non-3GPP access network, to the Trusted Non-3GPP access network and to the W-5GAN. The UE mentioned in this clause corresponds to 5G-RG, in the case of W-5GAN or to W-AGF in the case of support of FN-RG. In the case of N5CW devices access 5GC via trusted WLAN access networks, the UE mentioned in this clause corresponds to TWIF.

An UE cannot be paged over Non-3GPP access network.

If the UE states in the AMF are CM-IDLE and RM-REGISTERED for the non-3GPP access, there may be PDU Sessions that were last routed over the non-3GPP access and without user plane resources. If the AMF receives a message with a Non-3GPP Access Type indication from an SMF for a PDU Session corresponding to a UE that is CM-IDLE for non-3GPP access and the UE is registered over 3GPP access in the same PLMN as the one registered over non-3GPP access, a Network Triggered Service Request may be performed over the 3GPP access independently of whether the UE is CM-IDLE or CM-CONNECTED over the 3GPP access. In this case, the AMF provides an indication that the procedure is related to non-3GPP access, as specified in clause 5.6.8.

NOTE: The UE behaviour upon such network triggered Service Request is specified in clause 5.6.8.