5G Core Architecture & Call-Flow Analysis

📌 Overview

This project focuses on a conceptual analysis of the 5G Core network architecture, studying how control-plane and user-plane functions interact during UE registration and PDU session establishment.

The goal is to build strong foundational understanding of 5G Core internals before implementing hands-on lab simulations.

📐 5G Core Architecture

🧩 Core Network Functions

AMF (Access & Mobility Management Function)

• Handles UE registration and authentication
• Manages mobility and connection state
• Acts as the main control-plane entry point

SMF (Session Management Function)

• Manages PDU session lifecycle
• Selects UPF and configures data paths
• Controls user-plane behavior

UPF (User Plane Function)

• Forwards user data traffic
• Implements GTP-U tunneling
• Acts as the data plane anchor

🔁 Call-Flow Analysis

1️⃣ UE Registration

• UE sends registration request via gNB
• AMF performs authentication and security setup
• Registration accept is sent to UE

2️⃣ PDU Session Establishment

• UE requests data connectivity
• AMF forwards request to SMF
• SMF selects UPF and configures tunnels

📘 Key Learnings

• Clear separation of control plane and user plane
• Service-based architecture of 5G Core
• Importance of session lifecycle management
• Strong similarity to microservice-based systems

🟢 Current Status

• Architecture and call-flow analysis completed
• Hands-on lab simulation planned

🚀 Future Enhancements

• Deploy Open5GS / Free5GC using Docker
• Simulate UE registration and PDU sessions
• Analyze signaling logs
• Add monitoring and metrics