5G • Core Network
N1 Interface
N1 Reference Point (NAS)
Reference point between User Equipment and AMF transporting encrypted Non-Access Stratum (NAS) signaling.
Technical Explanation
The N1 interface carries all NAS signaling: 5GS Connection Management (5G-CM), Registration Management (5G-RM), Session Management (5G-SM messages tunneled to SMF), and SMS. N1 is encapsulated across the radio link (SRB1/SRB2 over Uu) and forwarded across N2 to the AMF.
Key Functions
- Transports Non-Access Stratum (NAS) control messages between UE and AMF
- Protected by NAS ciphering and integrity keys (K_NASenc, K_NASint)
- Carries registration, authentication, PDU session, and mobility commands
Specifications
3GPP TS 23.501, TS 24.501
Interfaces
N1
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