5.1.1 - 5.1.3 THE INTERNET

Topics from the Cambridge IGCSE (9-1) Computer Science 0984 syllabus 2023 - 2025

OBJECTIVES
5.1 Understand the difference between the internet and the world wide web
• The internet is the infrastructure
• The world wide web is the collection of websites and web pages accessed using the internet
5.2 Understand what is meant by a uniform resource locator (URL)
• A URL is a text-based address for a web page; it can contain the protocol, the domain name and the web page/file name
5.3 Describe the purpose and operation of hypertext transfer protocol (HTTP) and hypertext transfer protocol secure (HTTPS)

ALSO IN THIS TOPIC
 YOU ARE HERE | 5.1.1 - 5.1.3 THE INTERNET AND THE WWW
5.1.4 WEB BROWSERS
5.1.5 WEB PROTOCOLS
5.1.6 COOKIES AND SESSIONS
5.2.1 - 5.2.2 DIGITAL CURRENCY
 5.3.1 CYBER SECURITY
5.3.2 KEEPING DATA SAFE
TOPIC 5 REVISION CARDS
TOPIC 5 KEY TERMINOLOGY (CIE)
TOPIC 5 ANSWERS
TOPIC 5 TEACHER RESOURCES

SECTION 1 | 5.1 THE INTERNET AND THE WORLD WIDE WEB

THE WORLD WIDE WEB Vs THE INTERNET
Remember that the World Wide Web and the internet are two different things. The world wide Web is the protocols, language and webpages we access, whereas the internet is the network that provides a medium for the transfer of data.
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WHAT IS  THE INTERNET
The internet is simply a computer network that has grown and grown and is now the largest WAN available to the public all over the world. Underground cables all over the world carry data across the internet. When someone creates a webpage, the computer or server that holds/hosts the page is made available to the public and an address is provided on how to access the page. The internet is the network and components that provide a means for the data transfer.
Whilst various data transfer mediums are used the internet still predominantly uses cables. When you access the internet from your mobile phone data service the data will travel from your phone to the nearest receiving mast and then the rest of the journey for the data will be done via cables, even laid under the oceans throughout the world.

SECTION 2 | 5.2 UNDERSTAND WHAT IS MEANT BY THE TERM URL

WEB BROWSERS
A web browser is the application software we use to view webpages. Web browsers provide a front-end with user friendly features such as scroll bars, refresh and navigation buttons and work back-end to send and receive page requests along with interpreting the HTML that webpages are predominantly written in. Google Chrome and Microsoft Edge are examples of web-browser software. When you type a web address, normally in the bar at the top of the browser you are using the URL.

WHAT IS A URL
A URL or Uniform Resource Locator is the address of a webpage, the URL for the homepage of this website is www.computersciencecafe.com. The structure of a url can be broken up into 5 main parts, looking at the url of this page the parts would be:

PART 1 - PROTOCOL: https: - This refers to the protocol used the main two protocols are HTTP and HTTPS
PART 2 - DOMAIN NAME: computersciencecafe.com - This could be further divided into TLD (Top Level Domain) and SLD (Second Level Domain)
PART 3 - PATH OR SUB-DIRECTORY: /resources/internetprinciples - This refers to where there page requested is saved
PART 4 - QUERY: ? Used to provide dynamic web pages with custom features for the user.
PART 5 - PARAMETERS - Parameters show further breakdown of the query returned

Check out doepud and click on Anatomy of a URL for more information on URLs.

SECTION 3 | 5.3 THE PURPOSE OF HTTP AND HTTPS

In computer networking, a protocol is a set of rules and standards that defines how data is transmitted and received between devices on a network. Protocols are used to enable communication between different devices and systems by defining a common language that they can use to exchange information.
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HTTP (Hypertext Transfer Protocol) and HTTPS (Hypertext Transfer Protocol Secure) are two protocols used to transfer data between a client (usually a web browser) and a server (usually a web server). Both HTTP and HTTPS are communication protocols that allow for the transfer of data over the internet.

HTTP is the standard protocol used for transferring data between a client and a server on the web. It is a set of rules that determine how data is transmitted, how requests and responses are formatted, and how errors are handled. HTTP operates on top of the TCP/IP protocol, which is the standard protocol used for transmitting data over the internet.

HTTPS is a more secure version of HTTP that uses SSL/TLS (Secure Sockets Layer/Transport Layer Security) encryption to protect the data that is being transmitted. When a user connects to a website using HTTPS, the data that is transmitted between the client and server is encrypted, making it more difficult for hackers to intercept and steal sensitive information.
The SSL protocol (Secure Sockets Layer) has two layers:

• SSL Record Protocol Layer: This layer is responsible for breaking down the messages to be transmitted into manageable blocks called SSL records, and for ensuring that these records are reliably transmitted between the two communicating parties. The SSL record protocol layer also provides message integrity, confidentiality, and authenticity using encryption and hashing techniques.
• SSL Handshake Protocol Layer: This layer is responsible for initiating a secure SSL connection between the two communicating parties by negotiating the encryption algorithm and parameters to be used for the SSL session. The SSL handshake protocol layer also authenticates the communicating parties by exchanging digital certificates, and verifies the authenticity of the certificates by checking them against trusted Certificate Authorities.

These two layers of the SSL protocol provide a secure and reliable method for transmitting sensitive information over the internet. The SSL record protocol layer provides message confidentiality and integrity, while the SSL handshake protocol layer provides mutual authentication and negotiation of encryption parameters for the secure SSL session.

The purpose of HTTP is to enable the transfer of hypertext documents (such as HTML files) over the internet. It is the foundation of the World Wide Web and is used by web browsers to communicate with web servers. HTTP is a stateless protocol, which means that each request from the client is processed independently of previous requests.

The purpose of HTTPS is to provide a secure and encrypted way of transmitting data between a client and server. It is used to protect sensitive information such as passwords, credit card numbers, and other personal data. HTTPS ensures that the data being transmitted cannot be intercepted or tampered with by hackers or other third parties.

HTTP is the standard protocol used for transferring data between a client and server on the web, while HTTPS is a more secure version of HTTP that uses encryption to protect sensitive data.

ALSO IN THIS TOPIC

5.1.1 - 5.1.3 THE INTERNET AND THE WWW
5.1.4 WEB BROWSERS
5.1.5 WEB PROTOCOLS
5.1.6 COOKIES AND SESSIONS
5.2.1 - 5.2.2 DIGITAL CURRENCY
5.3.1 CYBER SECURITY
5.3.2 KEEPING DATA SAFE
TOPIC 5 REVISION CARDS
TOPIC 5 KEY TERMINOLOGY (CIE)
TOPIC 5 ANSWERS
TOPIC 5 TEACHER RESOURCES