5G • RAN
E1 Interface
E1 Control/User Plane Separation Interface
Interface between gNB-CU Control Plane (gNB-CU-CP) and gNB-CU User Plane (gNB-CU-UP).
Technical Explanation
Under 3GPP 5G CUPS architecture in the RAN, the Centralized Unit is decoupled into gNB-CU-CP (hosting RRC and PDCP-C) and gNB-CU-UP (hosting SDAP and PDCP-U). The E1 interface runs E1AP over SCTP/IP, allowing the CP to instantiate, modify, and terminate bearer processing pipelines in scalable cloud UP engines.
Key Functions
- Decouples Centralized Unit Control Plane from User Plane (CUPS in RAN)
- Allows independent scaling of control capacity and gigabit user plane throughput
- Enables UPF and CU-UP colocation at edge computing server sites
Specifications
3GPP TS 38.460, TS 38.463
Interfaces
E1
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