3GPP 24.501 v20.0.0 — the document's own text
6.2.15 Handling of Reliable Data Service
Taught in 4. Inside TS 24.501, the document at the centre (CT1 — the group that writes what your phone says, overview).
If the UE supports Reliable Data Service (see 3GPP TS 23.501 [8] and 3GPP TS 24.250 [14A]), the UE may request data transfer using Reliable Data Service for a PDU session in the Extended protocol configuration options IE during UE-requested PDU session establishment procedure (see clause 6.4.1).
The Reliable Data Service may only be used with PDU sessions for which the "Control Plane CIoT 5GS Optimisation" indicator is set or with PDU sessions using the control plane CIoT 5GS optimization when the AMF does not move such PDU sessions to the user plane.
The network shall inform the UE about the acceptance of UE's request for Reliable Data Service usage during the PDU session establishment procedure (see clause 6.4.1) in the Extended protocol configuration options IE.
If the network accepts the use of Reliable Data Service to transfer data for the specified PDU session, the UE shall use this PDU session exclusively for data transfer using Reliable Data Service; otherwise the UE shall not use this PDU session for data transfer using Reliable Data Service.