5G • RAN
Secondary Node (SN)
Dual Connectivity Secondary Node
The radio access node providing additional radio resources to the UE without control plane connection to the core.
Technical Explanation
The Secondary Node provides auxiliary radio capacity. In EN-DC (Option 3x), an en-gNB acts as the SN; in NE-DC (Option 4), an ng-eNodeB acts as the SN; in NR-DC, a secondary gNodeB acts as the SN. It manages the Secondary Cell Group (SCG) and coordinates with the Master Node across the Xn or X2 interface.
Key Functions
- Supplies auxiliary radio capacity without terminating core control plane
- Manages Secondary Cell Group (SCG) radio scheduling
- Coordinates with Master Node across inter-node Xn or X2 interface
Specifications
3GPP TS 38.300
Interfaces
XnX2
Related 5G Concepts
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