# [Intern] 28/06/2022 Introducing of O-DU High, FAPI, O-DU Low and their roles in the O-RAN
###### tags: `BMW-Lab`, `Intern`

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**Goal:** To understand the O-DU High, FAPI, O-DU Low and their roles in the O-RAN.
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**References**
- [Introducing of O-DU High, FAPI, O-DU Low and their roles in the O-RAN](https://docs.o-ran-sc.org/projects/o-ran-sc-o-du-l2/en/latest/overview.html)
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## O-DU High.

The O-DU High scans the list of cells received and sends corresponding cell configurations to 5G NR MAC. 5G NR MAC, in-turn configures the 5G NR SCH. It also configures the O-DU Low via the Lower MAC module. On receiving the cell config response, DU APP sends a gNB DU Config Update towards the O-CU.


## FAPI


This functional application platform interface (FAPI) is an internal interface within an integrated or disaggregated small cell. The 5G PHY API specification defines a control interface (P5) and a user plane or data path interface (P7).

## O-DU Low.

The O-DU low project focus on the baseband PHY Reference Design, which uses Xeon® series Processor with Intel Architecture. This 5GNR Reference PHY consists of a L1 binary and three kinds of interfaces which are validated on a CPU's platforms and demonstrates the capabilities of the software running different 5GNR L1 features.