Big picture
The internet is a global network of networks that connects billions of devices. The World Wide Web (WWW) is one service that runs on the internet: a vast collection of linked web pages. Email, chat, video calls and file transfer are other internet services.
This chapter explains how we find and use resources on the web: addresses (URLs, domain names, IP addresses), the software that delivers and displays pages (web servers and browsers), and features like add-ons and cookies. Expect definition and "differentiate between" questions.
Learning goals
Distinguish the internet from the World Wide Web.
Explain URLs, domain names, IP addresses and DNS.
Explain internet applications: email, chat and VoIP.
Distinguish websites, web pages, static and dynamic pages.
Explain web servers, web hosting and web browsers.
Explain browser settings, add-ons, plug-ins and cookies.
Core ideas
1. The internet and the WWW
Internet | World Wide Web |
|---|---|
A global network of interconnected networks (the infrastructure) | A collection of interlinked web pages and resources that runs on the internet |
Supports many services: web, email, file transfer, VoIP | One service of the internet, using HTTP/HTTPS |
Began with ARPANET (1969) | Invented by Tim Berners-Lee in 1989 at CERN |
The web uses three key technologies: HTML (to write web pages), URL (to address resources) and HTTP (to transfer pages).
2. Addresses on the internet
IP address: a unique numerical address for every device on a network, such as 192.168.1.5 (IPv4). IPv6 uses longer addresses to provide many more of them.
Domain name: an easy-to-remember name for a website, such as
ncert.nic.in. It has a top-level domain (the last part, such as.com,.org,.edu,.gov, or country codes like.in), and other levels before it.DNS (Domain Name System): converts domain names into IP addresses so that computers can locate websites. It works like a phone directory for the internet. This conversion is called domain name resolution.
URL (Uniform Resource Locator): the complete address of a resource on the web.
Parts of a URL — https://www.example.org/courses/ip.html:
Part | Example | Meaning |
|---|---|---|
Protocol |
| How the resource is accessed |
Domain name |
| The server hosting the resource |
Path / file |
| The location of the specific page |
3. Internet applications
Application | Description |
|---|---|
Sending messages and attachments electronically. An email address has a user name and domain: | |
Chat | Real-time text communication over the internet, one-to-one or in groups (messaging apps) |
VoIP (Voice over Internet Protocol) | Voice and video calls over the internet instead of traditional phone lines; low cost; needs a good connection (used by apps for video calling) |
Video conferencing | Real-time audio and video meetings among several people |
File transfer | Sending and downloading files (FTP, cloud storage) |
4. Websites and web pages
A web page is a single document on the web, written in HTML, which may contain text, images, video and hyperlinks.
A website is a collection of related web pages under one domain name. The first page is the home page.
A hyperlink is a clickable link to another page or resource.
Static web page | Dynamic web page |
|---|---|
Content is fixed; the same for every visitor until the developer changes the file | Content changes based on the user, time or database data |
Written mainly in HTML and CSS | Uses server-side scripts and databases (e.g. PHP, Python, JavaScript) |
Faster and simpler to create | More complex; more interactive |
Example: a school's "About Us" page | Example: an online exam result page, a shopping cart, a news feed |
5. Web servers and web hosting
A web server is a computer (and software) that stores websites and delivers web pages to browsers on request, using HTTP. When you type a URL, your browser sends a request to the web server, which sends the page back.
Web hosting is a service that provides space on a web server so a website is available on the internet. Hosting companies rent server space; the website owner registers a domain name and links it to the hosting server.
6. Web browsers
A web browser is software used to access and view web pages (for example, Google Chrome, Mozilla Firefox, Microsoft Edge, Safari, Opera).
Browser settings can be changed to set the home page, choose the default search engine, manage history and downloads, control privacy and security (block pop-ups, clear cookies), and enable private or incognito browsing (which doesn't save history and cookies after the session).
Add-ons and plug-ins:
An add-on (extension) adds extra features to the browser, such as ad blockers, translators or password managers.
A plug-in is software that lets the browser display or run specific content that it can't handle by itself, such as certain media formats or documents.
7. Cookies
A cookie is a small text file stored on the user's computer by a website. It remembers information such as login status, language preference, items in a shopping cart and browsing activity.
Benefits: personalised experience, staying logged in, saving preferences.
Concerns: tracking of browsing behaviour (especially third-party cookies used for advertising), and privacy risks.
Users can view, block or delete cookies in browser settings.
A reliable approach to questions
"Differentiate between" questions: internet vs web, static vs dynamic pages, website vs web page, add-on vs plug-in, web server vs web browser.
For a URL, split it into protocol, domain and path.
Remember DNS turns domain names into IP addresses.
For applications, match the task: real-time voice (VoIP), messages with attachments (email), real-time text (chat).
Connections that matter
Computer networks for IP explains the networks that carry internet traffic.
Societal impacts discusses privacy, cookies, phishing and cyber safety.
Computer Science: computer networks covers protocols such as HTTP, SMTP and POP3.
Common mistakes
Treating the internet and the WWW as the same.
Saying a web browser stores websites. A web server stores them; a browser displays them.
Confusing add-ons and plug-ins. Add-ons add features; plug-ins display particular content.
Saying incognito mode hides you from websites completely. It only avoids saving history and cookies on your device.
Revision checklist
I can distinguish the internet and the WWW.
I can explain IP addresses, domain names, DNS and the parts of a URL.
I can explain email, chat and VoIP.
I can distinguish static and dynamic web pages.
I can explain web servers, hosting and browsers.
I can explain add-ons, plug-ins and cookies.