3GPP 23.501 v20.2.0 — the document's own text
4.4.2.1 Architecture to support SMS over NAS
Taught in 21. Emergency calls, messages, voice and location (The 5G system architecture, in depth).
Figure 4.4.2.1-1 shows the non-roaming architecture to support SMS over NAS using the Service-based interfaces within the Control Plane.
Figure 4.4.2.1-2 shows the non-roaming architecture to support SMS over NAS using the reference point representation.
NOTE 1: SMS Function (SMSF) may be connected to the SMS-GMSC/IWMSC/SMS Router via one of the standardized interfaces as shown in TS 23.040 [5].
NOTE 2: UDM may be connected to the SMS-GMSC/IWMSC/SMS Router via one of the standardized interfaces as shown in TS 23.040 [5].
NOTE 3: Each UE is associated with only one SMS Function in the registered PLMN.
NOTE 4: SMSF re-allocation while the UE is in RM-REGISTERED state in the serving PLMN is not supported in this Release of the specification. When serving AMF is re-allocated for a given UE, the source AMF includes SMSF identifier as part of UE context transfer to target AMF. If the target AMF, e.g. in the case of inter-PLMN mobility, detects that no SMSF has been selected in the serving PLMN, then the AMF performs SMSF selection as specified in clause 6.3.10.
NOTE 5: To support MT SMS domain selection by IP-SM-GW/SMS Router, IP-SM-GW/SMS Router may connect to SGs MSC, MME and SMSF via one of the standardized interfaces as shown in TS 23.040 [5].
Figure 4.4.2.1-3 shows the roaming architecture to support SMS over NAS using the Service-based interfaces within the Control Plane.
Figure 4.4.2.1-4 shows the roaming architecture to support SMS over NAS using the reference point representation.
