Content for TS 33.163 Word version: 18.0.0
6 End to Middle Secured Data Protocol (EMSDP)
6.1 Introduction
6.2 EMSDP Protocol Description
6.2.1 Data Stack
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6 End to Middle Secured Data Protocol (EMSDP) p. 27
6.1 Introduction p. 27
The EMSDP protocol is used for the BEST service. This protocol runs between the UE and the HSE and has been optimised for efficient, secure transfer of both BEST user plane and control plane data.
6.2 EMSDP Protocol Description p. 27
6.2.1 Data Stack p. 27
Figure 6.2.1-1, Figure 6.2.1-2, Figure 6.2.1-3, and Figure 6.2.1-4 show examples with the LTE network of the data stacks for the EMSDP transfers (based on TS 23.401) between the HSE and the UE.
Figure 6.2.1-1: Non-IP PDU Type data stack for the EMSDP transfers over UP
(⇒ copy of original 3GPP image)
(⇒ copy of original 3GPP image)
Figure 6.2.1-2: Non-IP PDU Type data stack for the EMSDP transfers over NAS via the PDN GW
(⇒ copy of original 3GPP image)
(⇒ copy of original 3GPP image)
Figure 6.2.1-3: Non-IP PDU Type data stack for the EMSDP transfers over NAS via the SCEF
(⇒ copy of original 3GPP image)
(⇒ copy of original 3GPP image)
If the UE selects the non-IP PDU data type as defined in clause 4.3.17.8 of TS 23.401, the PDN GW encapsulates the non-IP EMSDP payload in PtP (IP and UDP as detailed in clause 4.3.17.8.3.3.2 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.
