Stop 01 · Internet & Web BasicsTopics · 1/14

Internet

In short

Every app you open, from Instagram to your college portal, runs on the internet. Once you know how data actually travels, everything else in web development clicks faster.

The global network of interconnected computers that lets browsers, servers and devices exchange data using standardized protocols like TCP/IP. It includes the physical network infrastructure, routers, switches, wireless networks, data centers, and the protocols that allow independently operated networks to communicate reliably across the world.

The jaadu postman sends small parcels down different roads to the same building.

Think of it like this

Like India Post, but super fast

Your message is cut into small parcels called packets. Each packet carries a 'from' and 'to' address, takes whichever road is free, and the receiver puts them back in order. That's the internet in one line.

Watch it happen

Packets on the move

Your laptop

Router

Internet

Server

packets 1, 2, 3

1/5Your laptop splits the message into small numbered packets and hands them to your Wi-Fi router.

The big ideas

What you need to know

A network of networks

Your home Wi-Fi, Jio's network and Google's data centres are separate networks that agree to talk to each other.

Data travels in packets

Big files are split into small packets. If one gets lost, only that packet is sent again, not the whole file.

Every device has an IP address

An IP address is how packets know where to go, a bit like a PIN code for computers.

TCP/IP are the rules

IP gets each packet to the right machine. TCP checks they all arrived and puts them back in order.

See it in code

A tiny example

bash

1# See the route your packets take to google.com2traceroute google.com      # macOS / Linux3tracert google.com         # Windows4 5# Check a server is reachable and how long it takes (macOS / Linux)6ping -c 4 google.com

Each line in the traceroute output is one router your packets passed through. The ms numbers show how long each hop took.

Save yourself the pain

Common mistakes

Oops

Thinking the internet and the web are the same thing.

Do this instead

The internet is the network. The web (websites over HTTP) is one service running on it, just like email and WhatsApp.

Oops

Picturing your data going from your phone to the server in one piece.

Do this instead

Picture lots of small packets, each finding its own way, then getting put back together at the other end.

Your mission

Trace your own packets

~10 min

Quick check

Your file reaches the other side, but one packet went missing on the way. What happens?

Go deeper

1Learn the basics of TCP/IP and how packets travel between devices. Focus on understanding the underlying reason it works, not only memorizing the definition.
2Understand the difference between the Internet and the World Wide Web. Be able to explain the concept in your own words and identify where it appears in a real application.
3Watch a short explainer on how data physically moves across networks.