1. Introduction

The TCP/IP Model, also known as the Internet Protocol Suite, is a practical framework that underpins the internet and most modern network communications. Unlike the theoretical OSI Reference Model, the TCP/IP model is a streamlined, four-layer architecture designed to facilitate real-world networking, particularly for the internet. Developed in the 1970s by pioneers like Vinton Cerf and Robert Kahn, it is the backbone of protocols like TCP and IP, which enable global connectivity.

This lecture note covers the four layers of the TCP/IP model—Link, Internet, Transport, and Application—detailing their functions, key responsibilities, and examples of protocols, devices, or technologies associated with each. It also explains data encapsulation and the model’s role in modern networking.