This test case is to validate mobile terminated control plane data transfer after initial UE message with CIoT control plane service request.

In this test case the CIOT UE ‘s EPS Connection Management or ECM is in Connected State and the UE sends Service Request to MME. After Service Accept, Mobile Terminated user data is sent by CIOT enabled MME in encapsulated format via NAS message S1_DOWNLINK_NAS_ESM_DATA_TRANSPORT.

The scenario executed is S1AP-NAS-Mobile terminating data flow Release 13.

The procedures which are running are –

• ESM Data Transport
• Initial UE Message
• S1 Setup
• Service Request

This test case is run as per 3GPP TS 23.401 and 3GPP TS 24.301

The call flow diagram with the messages exchanged is given below –