Section: 5.16.2.2 SMS over NAS transport
Content: 5G System supports SMS over NAS via both 3GPP access and non-3GPP access. During Registration procedure, a UE that wants to use SMS provides an "SMS supported" indication over NAS signalling indicating the UE's capability for SMS over NAS transport. "SMS supported" indication indicates whether UE can support SMS delivery over NAS. If the core network supports SMS functionality, the AMF includes "SMS allowed" indication to the UE, and whether SMS delivery over NAS is accepted by the network. SMS is transported via NAS transport message, which can carry SMS messages as payload.