16.14.6 AMF (Re-)Selection

The gNB implements the NAS Node Selection Function specified in TS 38.410 [16].

For an RRC_CONNECTED UE, when the gNB is configured to ensure that the UE connects to an AMF that serves the country in which the UE is located, if the gNB detects that the UE is in a different country to that served by the serving AMF, then it should perform an NG handover to change to an appropriate AMF, or initiate an UE Context Release Request procedure towards the serving AMF (in which case the AMF may decide to de-register the UE).

For the purpose of selecting an appropriate AMF, the 5GC may verify the UE location according to TS 23.501 [3] and TS 38.305 [42] after the UE has attached to the network.

NOTE: UE location verification for AMF selection should not be necessary if NTN cell(s) do not extend across countries.