3GPP 24.501 v20.0.0 — the document's own text

5.4.5.1 General

Taught in 4. Inside TS 24.501, the document at the centre (CT1 — the group that writes what your phone says, overview).

The purpose of the NAS transport procedures is to provide a transport of payload between the UE and the AMF. The type of the payload is identified by the Payload container type IE and includes one of the following:

a single 5GSM message;
SMS;
an LPP message (see 3GPP TS 37.355 [26]);

c1) an SLPP message (see 3GPP TS 38.355 [26A]);

an SOR transparent container;
a UE policy container;
a UE parameters update transparent container;
a location services message (see 3GPP TS 24.080 [13A]);
a CIoT user data container;
a Service-level-AA container;
a UPP-CMI container; or
Multiple payloads.

For payload type a) to e), g) and h), along with the payload, the NAS transport procedure may transport the associated information (e.g. PDU session information for 5GSM message payload).

For payload type k), the Payload container IE consists a list of payload container entries, where each of payload container entry contains the payload and optional associated information (e.g. PDU session information for 5GSM message payload).

NOTE: Payload type can be set to "Multiple payloads" if there are more than one payloads to be transported using the NAS transport procedures.