5G • RAN
F1-U Interface
F1 User Plane Interface
User plane interface between gNB-CU and gNB-DU running GTP-U over UDP/IP.
Technical Explanation
The F1-U interface transports user plane PDCP PDUs between the CU and the DU. It carries GTP-U encapsulation and includes user plane frame protocols that convey Downlink Data Delivery Status (DDDS), providing flow control information to ensure the CU does not overflow the DU's RLC buffers.
Key Functions
- Transports user plane PDCP packets between gNB-CU and gNB-DU
- Features Downlink Data Delivery Status (DDDS) flow control feedback
- Runs standardized GTP-U over UDP/IP transport
Specifications
3GPP TS 38.470, TS 38.475
Interfaces
F1F1-U
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