5G Core Networks

- Overview

A 5G core network is the central brain of a 5G network, managing and directing all traffic with enhanced flexibility, scalability, and security. 

It uses a service-based architecture (SBA) where modular network functions interact through standard APIs, allowing it to run in cloud environments and support advanced features like network slicing and edge computing. 

This enables higher speeds, lower latency, and the ability to create customized virtual networks for different applications.  

1. Key features:

• Service-Based Architecture (SBA): A modular, cloud-native design where network functions (NFs) are individual services that communicate with each other via standard APIs, promoting flexibility and efficiency.
• Network Slicing: Creates multiple, virtual networks on a single physical infrastructure. Each slice can be customized to meet the specific requirements of different applications, such as high bandwidth for video streaming or ultra-low latency for autonomous vehicles.
• Edge Computing: Integrates with edge computing, allowing data to be processed closer to the user or device. This significantly reduces latency and improves the efficiency of data-intensive applications.
• Enhanced Security: Provides advanced security features, including more robust encryption, which is crucial for protecting sensitive data, especially in private networks.
• Flexibility and Scalability: The modular and cloud-native nature allows the network to be easily scaled and adapted to accommodate growing demands and new technologies.

2. How it works: 

• Registration and Discovery: Network Functions (NFs) register their services with a Network Repository Function (NRF), allowing other NFs to discover and communicate with them.
• User Mobility and Access: The Access and Mobility Management Function (AMF) handles user registration, authentication, and tracking mobility.
• Session Management: The Session Management Function (SMF) manages user sessions, including controlling data flow and quality of service (QoS).
• Data Forwarding: The User Plane Function (UPF) is responsible for the actual forwarding of user data packets between the device and the network.
• Network Slice Selection: The Network Slice Selection Function (NSSF) selects the appropriate network slice for a user's session based on their application needs.

- 5G Core Network Functions

The main network functions of a 5G Core (5GC) are to establish connectivity, manage mobility, handle authentication and authorization, and control subscriber data and policies. 

Unlike 4G, 5G Core is a cloud-native, software-based system that enables greater flexibility and agility. It is the heart of the 5G network, providing high speeds, low latency, and supporting advanced capabilities like network slicing, which allows for the creation of multiple virtual networks on a single physical infrastructure. 

1. Core 5G network functions: 

• Mobility management: Tracks and manages the movement of a user device through the network.
• Authentication and authorization: Verifies that the user is legitimate and has permission to access the network and its services.
• Subscriber data management: Stores and manages user-specific information, such as their subscription details.
• Policy management: Controls the rules and policies that govern how network services are delivered, including data packet routing.

2. Key characteristics of the 5G Core:

• Cloud-native architecture: The 5GC is built on a virtualized, cloud-native architecture, allowing for greater flexibility and scalability.
• Service-Based Architecture (SBA): The architecture decomposes network functions into modular services that can be independently updated or scaled.
• Network slicing: The ability to create multiple, isolated virtual networks on the same physical infrastructure to cater to different services, like enhanced mobile broadband or ultra-reliable low-latency communications.
• Automation: New automation capabilities are essential for managing the complexity of the 5G network.
• Edge computing: The network's design supports edge computing, enabling data processing closer to the end user to further reduce latency for applications like autonomous vehicles. 

- Core Components of 5G Networks

The core components of a 5G network include the User Equipment (UE), the Radio Access Network (RAN) which includes the gNodeB (gNB) base station and the Distributed Unit (DU), and the 5G Core Network (5GC). 

The 5GC itself has functions like the Access and Mobility Management Function (AMF), and external infrastructure is also critical for services like security and load balancing. 

Core Components of 5G Networks: 

1. User Equipment (UE): The devices that users operate, such as smartphones, tablets, and other connected devices. 

2. gNodeB (gNB): The base station in the 5G Radio Access Network (RAN) that handles wireless communication for a specific area, also known as a cell. 

3. Distributed Unit (DU): A key part of the 5G RAN, which handles the real-time processing of radio functions. 

4. 5G Core Network (5GC): The central brain of the network, composed of cloud-native and service-based components that provide core functions and services.

• Access and Mobility Management Function (AMF): A specific function within the 5GC that manages a device's connection to the network and its location.
• Other core functions: Include the Session Management Function (SMF), User Plane Function (UPF), and Unified Data Management (UDM).

5. External Network Infrastructure: The underlying hardware and software that supports the 5G core, providing capabilities like load balancing, security, and the data center fabric.