23.0403GPPRelease 17Technical realization of the Short Message Service (SMS)TS
When a replying MS receives an original MT SM, it then has:
1) originating SME = TP‑Originating‑Address in the SMS‑DELIVER PDU,
2) original SC = RP‑Originating‑Address in RPS‑MT‑DATA, and
3) reply path exists/reply path does not exist = TP‑Reply‑Path in SMS‑DELIVER PDU (set/not set).