What Is a Network?
Every time you load a webpage, send a message, or stream a video, your device is communicating with other computers. This communication happens over a network — a system of connected devices that can exchange information with each other.
The Basic Idea
A network at its simplest is just two or more devices connected in a way that allows them to share data. Your home Wi-Fi network connects your phone, laptop, and smart TV. Your office network connects dozens or hundreds of computers. The internet connects billions of devices worldwide.
Networks require three things:
- Devices — computers, phones, servers, or any hardware that sends or receives data
- Connections — physical cables, wireless signals, or other media that carry data
- Rules — agreed-upon protocols that define how devices communicate
How Data Travels
When you send data across a network, it doesn't travel as one continuous stream. Instead, it's broken into small chunks called packets. Each packet contains a piece of your data plus addressing information — like putting a letter in an envelope with a destination address.
These packets travel independently through the network, potentially taking different routes, then reassemble at the destination. This approach is more resilient than a single continuous connection — if one path is congested, packets can take another.
Physical and Wireless Connections
Networks use various media to carry data:
Wired connections use physical cables. Ethernet cables connect devices in homes and offices. Fiber optic cables carry data as light pulses across continents and under oceans.
Wireless connections use radio waves. Wi-Fi connects devices within a building. Cellular networks connect phones across cities. Satellite links reach remote locations.
Each medium has tradeoffs. Wired connections are typically faster and more reliable. Wireless connections offer mobility and convenience.
The Postal System Analogy
Think of a network like a postal system. Your device is a house. The network infrastructure — cables, routers, switches — is like roads, sorting facilities, and delivery trucks. Packets are letters traveling through the system.
Just as mail follows addresses to reach destinations, network packets follow IP addresses to find their target devices. And just as postal systems have rules about envelope sizes and addressing formats, networks have protocols that standardize communication.
Why Networks Matter
Networks are the foundation of modern computing. Without them, every computer would be an isolated island. With them, we have email, websites, cloud storage, video calls, and countless other services that depend on devices talking to each other.
Understanding networks helps you understand how the internet works, why some connections are slow, and how applications communicate across the world.