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Computer Networks · Class 12 · Network Protocols · Web Pages and Files
networksprotocols⏱️ 7 min read

HTTP

🎬 This chapter has a 10:53 video: Network Protocols →

Every time you open a web page, two programs have a very short conversation. Your browser asks for the page. A computer somewhere else sends it. The rules for that conversation are called HTTP.

1What HTTP is

HTTP
HTTP stands for HyperText Transfer Protocol. It is the main protocol used to access the World Wide Web. It is a request–response protocol: the web browser sends a request, and the web server sends back a response.

Two words from the next chapter, Web Services, in one line each:

  • A web browser (Chrome, Firefox, Edge) is the program you use to open web pages. It is the client — the one that asks.
  • A web server is a computer that stores web pages and sends them to browsers. It is the server — the one that answers.

Hypertext is text with links in it: click one, and you go to another page. HTTP is the protocol that transfers those pages.

The browser asks, the server answers

Choose a page, then play the story or go one step at a time. Drag sideways to turn.

Ask for
Press ▶ Play to follow one request to the web server and the response back.

2Request and response

Every page you open is at least one request and one response:

  1. You type an address, such as http://www.ncert.nic.in, or click a link.
  2. The browser sends an HTTP request to the web server where that site is kept.
  3. The web server finds the page and sends an HTTP response containing it.
  4. The browser shows the page.

Every response starts with a short status. 200 OK means “here is your page”. 404 Not Found means the server is working but has no page at that address — which is why a mistyped link gives you a 404 page.

Think of a library counter

You hand the librarian a slip with a book’s name (the request). The librarian looks on the shelves and hands the book back (the response) — or says “we don’t have that one” (a 404). You never walk into the shelves yourself.
Where it came from
HTTP was developed at CERN, in Switzerland, by a team led by Tim Berners-Lee, starting in 1989 — together with HTML and the URL, the three things the web is built from.
A misprint in your NCERT book
NCERT’s example prints the address as http//www.ncert.nic.in. The colon is missing: it is http://www.ncert.nic.in.

HTTP only decides what the browser and server say to each other. Getting the request and the page across the Internet, in packets, is the job of TCP/IP — HTTP runs on top of it.

3From the board papers

1
Which of the following is the correct protocol used for accessing a Web page? (A) HTTP (B) FTP (C) VoIP (D) SMTPCBSE compartment exam 2026
1 mark
▶Show the answer

(A) HTTP. FTP moves files, VoIP carries calls, and SMTP sends email.

2
Which protocol is used to transmit hypertext across the web?CBSE board exam 2026 (part of a 2-mark question)
1 mark
▶Show the answer

HTTP — HyperText Transfer Protocol (or HTTPS, its secure form).

3
Expand the term HTTP.CBSE sample paper 2025-26 (with FTP)
1 mark
▶Show the answer

HyperText Transfer Protocol.

4Check yourself

Quick Check

In HTTP, which program sends the request?

Quick Check

A web server receives a request for a page it does not have. What does it do?

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