Learning Objectives

By the end of this section, you will be able to:

• Explain the purpose of the Network Layer.
• Understand how Layer 3 fits into the OSI model.
• Describe what an IP packet is.
• Differentiate between IPv4 and IPv6.
• Explain the role of routers.
• Understand how packets move between different networks.
• Recognize why Layer 3 is fundamental to cloud computing and DevOps.

Introduction

Imagine you want to send a parcel from Port Harcourt, Nigeria to Berlin, Germany.

The parcel will travel through several cities, airports, and distribution centers before reaching its destination.

The postal service does not need to know what is inside the parcel. Its responsibility is to determine the best route to deliver it.

The Network Layer (Layer 3) works in a similar way.

Instead of moving parcels, it moves IP packets across interconnected networks.

Its primary responsibility is to determine how data travels from one network to another until it reaches the correct destination.

Without the Network Layer, communication would be limited to devices on the same local network.