Learning Unit 5: The Internet, Intranets and Extranets
The Internet and the World Wide Web
Understanding the Internet
The Internet is a network of networks, connecting millions of computers
It is a decentralized organisation, no single entity owns or controls it
Networks are locally managed but globally interconnected through collaboration
Internet Backbone
Built with high-bandwidth fibre-optic cables
Includes interconnected commercial, academic, government, and high-capacity data
routers
Acts as the foundation for all other networks
Network Access Points (NAPs)
Connect LANs to the Internet backbone
Route Internet traffic efficiently for smooth network connection
The World Wide Web
Tim Berners transformed the Internet into a graphical, multimedia experience
Web organizes information using hypermedia: documents embedded with audio, video, text,
and images
Internet Access Requires:
A PC with a modem/network connection
An account with an Internet Service Provider (ISP)
Appropriate network cabling (LAN or telephone line)
TCP/IP installed on your computer
Internet applications like a web browser (e.g., Chrome) and email client (e.g., Outlook)
The Domain Name System (DNS)
Computers are identified by IP addresses (e.g., 208.77.188.166)
Humans use domain names (e.g., www.advtech.co.za) for ease of use
Example: http://www.musica.co.za
http → Hypertext Transfer Protocol (to send and receive hypertext documents)
www → Web server domain (World Wide Web)
musica → organization name (name of the server computer containing the web documents)
.co → type of organization (commercial site)
.za → indicates country (South Africa)
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, Domain Types (TLDs):
TLD Use Case
.com Commercial
organizations
.co.za SA commercial
organizations
.edu / . Educational institutions
ac
.gov Government
organizations
.info Information distributors
.int International
organizations
.net Network providers
.org Non-profit organizations
.web Web-related businesses
.biz Businesses of all sizes
How DNS Works:
DNS servers translate domain names into IP addresses
Enables user-friendly browsing by associating URLs to their IP addresses
Types of Internet Connections
Various technologies enable Internet access:
Dial-Up
Cable Modem
Digital Subscriber Line (DSL)
Transmits data over telephone lines:
– Symmetric DSL (SDSL): Equal upload & download speeds
– Asymmetric DSL (ADSL): Faster downloads than uploads
– Very High-Speed DSL (VDSL): High speeds over short distances
Business Lines
T1 and T3 Lines:
– High-speed, reliable lines provided by telecom companies
– Can transmit the equivalent of 24 standard phone lines using only 2 pairs of copper
wires
Navigation Tools, Search Engines And Directories
Navigational Tools
Navigational tools help users move from one website to another.
Web browsers like Chrome, Safari, Firefox, and Internet Explorer act as gateways to the internet.
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The Internet and the World Wide Web
Understanding the Internet
The Internet is a network of networks, connecting millions of computers
It is a decentralized organisation, no single entity owns or controls it
Networks are locally managed but globally interconnected through collaboration
Internet Backbone
Built with high-bandwidth fibre-optic cables
Includes interconnected commercial, academic, government, and high-capacity data
routers
Acts as the foundation for all other networks
Network Access Points (NAPs)
Connect LANs to the Internet backbone
Route Internet traffic efficiently for smooth network connection
The World Wide Web
Tim Berners transformed the Internet into a graphical, multimedia experience
Web organizes information using hypermedia: documents embedded with audio, video, text,
and images
Internet Access Requires:
A PC with a modem/network connection
An account with an Internet Service Provider (ISP)
Appropriate network cabling (LAN or telephone line)
TCP/IP installed on your computer
Internet applications like a web browser (e.g., Chrome) and email client (e.g., Outlook)
The Domain Name System (DNS)
Computers are identified by IP addresses (e.g., 208.77.188.166)
Humans use domain names (e.g., www.advtech.co.za) for ease of use
Example: http://www.musica.co.za
http → Hypertext Transfer Protocol (to send and receive hypertext documents)
www → Web server domain (World Wide Web)
musica → organization name (name of the server computer containing the web documents)
.co → type of organization (commercial site)
.za → indicates country (South Africa)
Page 1 of 8
, Domain Types (TLDs):
TLD Use Case
.com Commercial
organizations
.co.za SA commercial
organizations
.edu / . Educational institutions
ac
.gov Government
organizations
.info Information distributors
.int International
organizations
.net Network providers
.org Non-profit organizations
.web Web-related businesses
.biz Businesses of all sizes
How DNS Works:
DNS servers translate domain names into IP addresses
Enables user-friendly browsing by associating URLs to their IP addresses
Types of Internet Connections
Various technologies enable Internet access:
Dial-Up
Cable Modem
Digital Subscriber Line (DSL)
Transmits data over telephone lines:
– Symmetric DSL (SDSL): Equal upload & download speeds
– Asymmetric DSL (ADSL): Faster downloads than uploads
– Very High-Speed DSL (VDSL): High speeds over short distances
Business Lines
T1 and T3 Lines:
– High-speed, reliable lines provided by telecom companies
– Can transmit the equivalent of 24 standard phone lines using only 2 pairs of copper
wires
Navigation Tools, Search Engines And Directories
Navigational Tools
Navigational tools help users move from one website to another.
Web browsers like Chrome, Safari, Firefox, and Internet Explorer act as gateways to the internet.
Page 2 of 8
