If the UE selects the non-IP PDU data type as defined in clause 18.104.22.168 of TS 23.401, the PDN GW encapsulates the non-IP EMSDP payload in PtP (IP and UDP as detailed in clause 22.214.171.124.3.3.2 of TS 23.401) for the communication with the HSE. In case of the EMSDP is in IP PDU Type, the PtP encapsulation is unnecessary, and the UE's IP packet is directly forwarded to the HSE. This is shown on Figure 6.2.1-2.
In all four scenarios for UE-to-EAS BEST sessions, the HSE may forward the EMSDP user plane unmodified to the EAS. When the session uses a non-IP PDU Type connection that terminates at the SCEF, SCEF API's are used to forward the EMSDP user plane unmodified to the HSE. The signalling plane always terminates in the HSE.