Computer Networks

Core computer networking topics include the OSI and TCP/IP models, network topologies, IP addressing and subnetting, network devices, transmission modes and media, routing protocols, network security, wireless networks, MAC and IP addressing, error detection and correction, LAN/WAN/MAN, DNS and HTTP, and Quality of Service (QoS). This page organises all of them into 14 structured modules.

The OSI model is a seven-layer reference framework that describes networking functions in theory, while the TCP/IP model is a four-layer practical model that the internet actually runs on. The OSI model separates the application, presentation and session functions that TCP/IP combines into a single application layer. Our dedicated lesson on OSI vs TCP/IP covers the mapping in detail.

Start with Module 01 (OSI & TCP/IP models) to understand how networks are layered, then learn IP addressing and subnetting, followed by network devices and routing. Once the fundamentals are clear, move on to network security, DNS, and Quality of Service. Following the modules in order gives you a complete, exam-ready foundation.

Subnetting divides a single large IP network into smaller, more manageable sub-networks. It improves performance by reducing broadcast traffic, strengthens security through isolation, and uses address space more efficiently. The IP Addressing & Subnetting module covers IPv4/IPv6, CIDR, subnetting and supernetting step by step.

Yes — every lesson linked on this page is completely free to read. Each opens a detailed, beginner-friendly guide written for students, exam preparation, and working IT professionals who want a quick, reliable revision.