How the OSI Model's Seven Layers Work Together to Deliver a Network Request

The OSI model is a seven-layer framework that standardises how data travels across networks, from application software down to physical signals like electrical or radio waves. Each layer has a distinct role: the Application layer handles user-facing data, Transport breaks it into segments, Network adds IP addresses for routing, and lower layers manage local addressing and physical transmission. As data moves down the stack, each layer wraps the previous layer's output with its own header — a process called encapsulation — and the receiving device reverses this through decapsulation. The model was developed to replace proprietary, vendor-specific networking systems that could not communicate with one another. Understanding it helps explain why modern internet infrastructure — including routers, switches, and encryption protocols — is designed the way it is.