Study Guide

Internet technologies

CIE A-Level Computer ScienceΒ· Unit 2: Communication, Topic 4Β· 20 min read

1. Internet vs World Wide Webβ˜…β˜…β˜†β˜†β˜†β± 5 min

This is one of the most commonly confused distinctions in CIE exams, and is often tested as a short 2-3 mark question. The two concepts are fundamentally different.

πŸ“˜ Definition

Internet

A global, public interconnected network of computer networks that uses the TCP/IP protocol suite to exchange data. It includes all physical infrastructure: undersea cables, routers, servers, satellites, and end-user devices.

Example:

A home router connected to an ISP is part of the global internet infrastructure.

The World Wide Web (WWW) is just one of many services that run over the internet. Other internet services include email, FTP, VoIP, and cloud storage, which do not require the WWW to function.

πŸ“ Worked Example

A student claims 'the internet and World Wide Web are the same thing'. Evaluate this claim for 2 marks.

  1. 1
    1. The claim is incorrect; the two are distinct concepts:
  2. 2
    1. The internet is the global physical network of interconnected devices that uses TCP/IP for communication.
  3. 3
    1. The World Wide Web is a service that runs on top of the internet, consisting of interlinked hypertext documents.
  4. 4
    1. Marking: 1 mark for identifying the claim is wrong, 1 mark for the correct distinction.

Exam tip:

Always remember: the internet is the network, WWW is a service that runs on the network. This is a common easy mark if you get the distinction right.

2. URLs and Domain Name System (DNS)β˜…β˜…β˜…β˜†β˜†β± 7 min

Every resource on the WWW needs a unique address so browsers can locate it. Two core addressing systems are URLs and DNS.

πŸ“˜ Definition

Uniform Resource Locator (URL)

URLURL

A full address that specifies the location of a specific resource (web page, image, file) on the web, including the protocol, domain name, resource path, and optional query parameters.

Example:

https://example.com/blog/post1?id=123 is a complete URL.

Humans cannot easily remember numeric IP addresses, so we use human-readable domain names (e.g. google.com). DNS is the service that translates these domain names to IP addresses that routers use to locate the correct server.

πŸ“ Worked Example

Outline the steps a browser takes to resolve www.cambridge.org to an IP address.

  1. 1
    1. The browser first checks its local cache to see if it already has the matching IP address stored.
  2. 2
    1. If not found locally, the browser sends a DNS query to the ISP's recursive DNS server.
  3. 3
    1. The recursive server queries the .org top-level domain (TLD) server, which redirects it to Cambridge's authoritative DNS server.
  4. 4
    1. The authoritative server returns the correct IP address for www.cambridge.org back to the browser.
  5. 5
    1. The browser can now send an HTTPS request to the IP address to fetch the web page.

Exam tip:

The direction of DNS translation is almost always tested. DNS translates domain names to IP addresses, not the reverse.

3. Web Hosting and Web Serversβ˜…β˜…β˜†β˜†β˜†β± 4 min

To make a website publicly available, its files must be stored on a server permanently connected to the internet. Web hosting is the service that provides this access.

πŸ“˜ Definition

Web Hosting

A service provided by hosting companies that allocates storage and bandwidth on a public web server to store a website's files (HTML, CSS, images, code) so they can be accessed by any user connected to the internet.

Example:

A small local business may pay a monthly fee for shared hosting for their 5-page business website.

There are three common hosting tiers: shared hosting (multiple sites on one server, low cost), dedicated hosting (one site per server, high performance), and cloud hosting (distributed across multiple virtual servers, high scalability).

πŸ“ Worked Example

Explain why a large online retailer would choose dedicated hosting over shared hosting for their main website.

  1. 1
    1. Shared hosting allocates one physical server to multiple unrelated websites, so all sites share the server's CPU, RAM, and bandwidth.
  2. 2
    1. A large online retailer gets very high volumes of traffic 24/7, especially during sales events, and needs guaranteed fast load times.
  3. 3
    1. Dedicated hosting gives the retailer full access to all the server's resources, so the site will not slow down or crash even during peak traffic.
  4. 4
    1. Dedicated hosting also provides better security, which is critical for a retailer storing customer payment data.

4. Common Internet Servicesβ˜…β˜…β˜†β˜†β˜†β± 4 min

CIE expects you to know the uses of common internet services beyond the WWW:

  • Email: Uses SMTP for sending mail, POP3 and IMAP for receiving mail from mail servers

  • File Transfer Protocol (FTP): Designed for reliable transfer of large files between computers, commonly used to upload website files to a web host

  • Voice over IP (VoIP): Enables real-time voice and video calls over the internet, used by Zoom and WhatsApp

  • Cloud Storage: Stores user files on remote internet-connected servers, accessible from any device, e.g. Google Drive, Dropbox

πŸ“ Worked Example

State which internet service a web developer would use to upload a completed website from their local computer to a web hosting server, and justify your answer.

  1. 1
    1. The appropriate service is File Transfer Protocol (FTP).
  2. 2
    1. FTP is specifically designed to reliably transfer large files (website HTML, CSS, images, code) between computers over the internet.
  3. 3
    1. FTP supports secure authentication (username/password) to ensure only the authorised developer can upload files to the web server, which is a required feature for web hosting.

5. Common Pitfalls

Wrong move:

Claiming the internet and World Wide Web are the same thing

Why:

This is the most common mistake in this topic, and costs easy marks in 2 mark questions

Correct move:

Always state: the internet is the global network; the WWW is a service that runs over the internet

Wrong move:

Describing DNS as converting IP addresses to domain names

Why:

Candidates often reverse the direction of translation

Correct move:

DNS always translates human-readable domain names to machine-readable IP addresses

Wrong move:

Confusing domain registration with web hosting

Why:

Candidates often mix up these two separate services

Correct move:

Domain registration reserves your domain name; web hosting stores your website's actual files on a public server

Wrong move:

Claiming FTP is used to view web pages in a browser

Why:

Candidates mix up FTP with HTTP/HTTPS

Correct move:

HTTP/HTTPS is used by browsers to load web pages; FTP is used to transfer files between servers

6. Quick Reference Cheatsheet

Concept

Key Definition

Exam Tip

Internet

Global network of connected devices using TCP/IP

Not the same as WWW

WWW

Service running over internet, interlinked hypertext

One of many internet services

URL

Full address of a web resource

Includes protocol + domain + path

DNS

Translates domain names to IP addresses

Direction is always tested

Web Hosting

Stores website files on public server

Domain registration β‰  hosting

FTP

File transfer between networked devices

Used to upload website files to hosting

7. Frequently Asked

What is the difference between the internet and the WWW?

The internet is the physical global network of connected computers and infrastructure. The World Wide Web is one service that runs over the internet, consisting of interlinked hypertext pages.

Is domain registration the same as web hosting?

No. Domain registration only reserves your chosen domain name for your use. Web hosting provides server space to store your website's actual files (HTML, images, code) so they are accessible online.

When this came up on past exams

AI-estimated based on syllabus patterns β€” cross-check with official past papers for accuracy. Use only as revision-focus signals.

  • 2022 Β· 12

    DNS and URL explanation question

  • 2023 Β· 11

    Internet vs WWW distinction

  • 2024 Β· 13

    Web hosting types question

Going deeper

What's Next

The core internet concepts you learned here underpin all other communication topics in CIE 9618 Unit 2. DNS, client-server communication, and internet services are foundational for network security, web development, and cloud computing topics that you will study next. Mastering these basic distinctions will help you answer more complex exam questions that combine multiple communication concepts.