What Are Computer Networks? A Simple Guide for Students
By K. Boopathikumar, CEO & Founder · 14 November 2026 · 5 min read
A computer network is two or more devices connected so they can share data. Your phone on home Wi-Fi, a college computer lab and the whole internet are all networks; the internet is simply a network of networks.
Networking is not only for network engineers. Developers, cloud engineers, testers and security analysts all hit networking problems, and the person who understands them solves issues in minutes instead of days.
The building blocks
- IP address: the address of a device on a network, such as 192.168.1.10 at home.
- Router: connects networks together and decides where each packet goes.
- Switch: connects devices inside one local network.
- Port: a number that says which program on a device should get the data (web servers usually use 443 for HTTPS).
- DNS: the internet's phone book, turning names like trainingtrains.com into IP addresses.
TCP and UDP
TCP makes sure data arrives complete and in order, resending anything lost. It is used for web pages, email and file downloads. UDP is faster but does not guarantee delivery, which suits video calls and online games, where a late packet is useless anyway.
What happens when you open a website
This question is asked in many interviews. If you can explain each step clearly, you understand the core of networking.
- Your browser asks DNS for the site's IP address.
- It opens a TCP connection to that address on port 443.
- TLS sets up encryption, which is the padlock in the address bar.
- The browser sends an HTTP request, and the server sends back the page.
- The browser then requests images, styles and scripts the page needs.
How to practise
Use commands you already have: ping, tracert (traceroute on Linux and Mac), nslookup and ipconfig. Install Wireshark and watch the packets when you open a website. Cisco Packet Tracer lets you build and break virtual networks for free.
The Network Engineer track goes from these basics to routing and security, and the network engineering internship gives you hands-on tasks with review.