Steps involved in 5G Registration Call Flow:
1️⃣ Initiation 📱💡:
The UE (User Equipment) initiates the registration process after establishing an RRC (Radio Resource Control) connection with the 5G network.
2️⃣ Registration Request 📝📤:
The UE sends a Registration Request NAS (Non-Access Stratum) message to the 5G Core Network (5GC), containing its SUPI/PEI (Subscription Permanent Identifier/Public Equipment Identity) and requested NSSAI (Network Slice Selection Assistance Information).
3️⃣ Authentication Request 🔒🔍:
The AMF (Access and Mobility Management Function) sends an Authentication Request message to the UE, which contains the authentication challenge.
4️⃣ Authentication Response 🔑📥:
The UE verifies the authentication challenge, calculates the response, and sends an Authentication Response message to the AMF.
5️⃣ Authentication Result ✅🔓:
The AMF verifies the received response, and if successful, the authentication process is considered complete.
6️⃣ Security Mode Command 🛡️📲:
The AMF sends a Security Mode Command message to the UE to activate the NAS security context.
7️⃣ Security Mode Complete 🛡️✔️:
The UE sends a Security Mode Complete message to the AMF, indicating that the NAS security context has been activated.
8️⃣ Registration Accept 📨👍:
The AMF sends a Registration Accept NAS message to the UE, which contains the GUTI (Globally Unique Temporary Identifier) and other relevant network information.
9️⃣ Registration Complete 🎉✅:
The UE sends a Registration Complete NAS message to the AMF, confirming the successful completion of the registration procedure.
