N2 Interface
The reference point between the (R)AN and the AMF carrying NGAP signaling for UE context management, handover, and paging procedures.
N2 is the control-plane link between the radio access network and the AMF, and it runs the NGAP protocol (over SCTP). This is where the RAN and core coordinate everything about a UE that isn't user data: setting up and releasing the UE's context in the gNB, carrying the NAS messages back and forth, triggering paging, and managing handovers that cross gNBs.
It's the 5G counterpart to S1-AP in LTE, and if you've worked S1 issues the rhythm feels familiar. A typical exchange is the initial UE message that brings a new subscriber to the AMF, the context-setup that arms the gNB with security and bearer info, and the handover signalling when N2 has to be involved because Xn between gNBs isn't available or sufficient. SCTP underneath means you also care about association health — a flapping N2/SCTP link shows up as mass registration churn.
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