What Is a Computer Network?
- Networking Fundamentals & OSI Model
- TCP/IP Model
- Network Topologies
- IP Addressing & Subnetting
- Routing Algorithms & Protocols
- Switching Concepts
- Transport Layer Protocols (TCP & UDP)
- Application Layer Protocols
- Network Security & Firewalls
- Wireless Networking & Wi-Fi
- Network Address Translation (NAT)
- DNS Deep Dive
- Congestion Control & Flow Control
- Error Detection & Correction
- Network Devices
- VPN & Tunneling
- Load Balancing & CDN Networking
- Socket Programming
- Network Troubleshooting Tools
- Physical Layer & Transmission Media
- Data Link Layer & MAC Addressing
- Ethernet Protocol
- ARP (Address Resolution Protocol)
- ICMP Protocol
- Unicast, Multicast, Broadcast and Anycast
- Proxy Servers
- Port Numbers Reference
- Network Performance Metrics
- Quality of Service (QoS)
- Software-Defined Networking (SDN)
- HTTP/2 and HTTP/3 Overview
- 5G and Mobile Networks
- IoT Networking Basics
- VoIP Networking Basics
Defining a Computer Network
A computer network is a group of two or more devices connected together so they can share data and resources. That connection can be a physical cable, a wireless radio signal, or a chain of intermediate devices spanning the globe - the defining feature is not the medium, but the ability for devices to exchange information reliably.
Why Networks Exist
- Resource sharing - one printer, one internet connection, or one file server can serve many devices.
- Communication - email, messaging and video calls all depend on a network moving data between people.
- Centralized data - a shared database or file store means everyone works from the same information instead of scattered copies.
The Basic Building Blocks
| Component | Role |
|---|---|
| Node | Any device on the network - a computer, phone, printer or server |
| Link | The medium connecting nodes - a cable or a wireless signal |
| Protocol | The agreed rules two nodes follow so their messages make sense to each other |
Networks Come in Different Sizes
A network can be as small as two laptops connected directly to each other, or as large as the internet itself - billions of devices, none of which need to know about most of the others, connected through layers of routers and links. The same core ideas - nodes, links and protocols - apply at every scale.