Topic 11: The Internet & World Wide Web
The Internet is a worldwide connection of many
thousands of computer networks. These networks use
a common language, Transmission Communication
Protocol/Internet Protocol, TCP/IP, to communicate.
The networks are connected to one another through
communications channels, many of which remain
permanently open. The standardised organisation and
structure of the networks that form the Internet enables
the instantaneous transmission and reception of digital
data in many forms between computer systems across
the globe.
The Internet is a cooperative community of networks.
No particular body owns the Internet. It is made up of
many small parts in many different countries. Within
each country, there is an organisation that supports the
Internet and provides the main communications
channels. Within the world, there is a group that
coordinates the overall network. It is a facility which
anyone can use. People often comment that the
Internet belongs to everyone and to no one.
11.1 The Internet Network
The Internet is structured in an hierarchical form. At
the top, each country has at least one major backbone
network that carries Internet data between its main
cities and centres. These networks consist of high
speed communication channels that carry the digital
data. There are then many smaller networks that
connect homes, schools, universities and commercial
users to the backbone networks. A network of
channels are then used for connections between
countries and continents. Today, there are more than
500 thousand networks in all the countries in the world.


Network C
eg. Telstra Internet

Network A
eg. Edith Cowan
University, WA





Network D
the bandwidth. Bandwidth is measured in terms of the
number of bits of information that can be passed
through a channel in one second. A channel with a
40 Mbps (Mega bits per second) bandwidth can carry
over 40 million bits of information per second. Internet
channels now carry data at the rate of billions of bits
per second Gbps.
The Internet involves a large number of channels and
data can travel many ways between different points.
The capability of the Internet to redirect data traffic
from one channel to another when the need arises is a
major strength of the system.
11.3 The Internet in Australia
Australians are very big users of the Internet. There
were over 13 million Internet users in Australia in
2004 which represents 66% of the population.
In Australia, the Internet backbone is provided and
maintained by Telstra Internet Direct and their partner
Reach. Telstra Internet Direct coordinates all Internet
network access in Australia. The Internet is supported
by a backbone network (Figure 1.2) which connects the
various capital cities. The network comprises dual
channels to ensure services are never broken.
Telstra Internet Direct connects to the global Internet
through high bandwidth underwater cables.
Bandwidths are1.265 Mbps to the USA, 200 Mbps to
NZ, 55 Mbps to Japan, 8 Mbps to South Korea, 45
Mbps to Hong Kong and 45 Mbps to Singapore.


Network B
eg. Qantas, NSW
eg. AT&T, USA

Network E
eg. Apple, California
Figure 11.1 The Internet
The Internet consists of many small networks which
communicate using the TCP/IP protocol.
11.2 Bandwidth
The communication channels that form the Internet
backbone have a large but limited capacity for carrying
data. The amount of data a channel can carry is called
Topic 11: The Internet and World Wide Web
Figure 11.2 The Internet Backbone in Australia
http://www.telstra.com.au/internetdirect
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It is interesting to observe the growth of the Internet in
Australia. In 1997 Telstra's domestic Internet capacity
exceeded 100 Mbps. The bandwidth of the channels
was very small by today’s standards, Mbytes as
compared to Gbytes (Figure 1.3)
Darwin •
Korea
2 Mb
the data, just in case something gets jumbled during the
journey. If and when errors are found, for example,
missing packets or jumbled data, TCP gets the original
computer to send the data again.
Japan
2 Mb
2 Mb
8 Mb
6 Mb
Brisbane
•
USA
4 Mb
12 Mb
106 Mb USA
Perth
6 Mb
•
4 Mb
Adelaide
•6 Mb
Melbourne
• Sydney
4 Mb
8 Mb
34 Mb
•
4 Mb
• Canberra
8 Mb
4 Mb
NZ
USA
32 Mb
Hobart •
Figure 11.3
The Australian Internet Backbone in 1997
11.4 TCP/IP
Probably, the most important part of the Internet is the
data transmission protocol on which it is based,
TCP/IP. The TCP/IP standard describes a set of
methods for all Internet communications use. It is the
Internet's method of transmitting data and ensuring its
accurate reception at the receival point.
To understand how TCP/IP works, it is necessary to
consider the network itself and the problems associated
with sending data across such a vast system. The
Internet is comprised of many host computers,
computers which connect and manage the smaller
networks. When data is to be sent over the Internet, it
is broken up using the IP protocol into small packets,
each of which contains some of the data and the
address where it is being sent.
The data is then transmitted through the
communications channels. Often it doesn’t all go the
same route. The computers which control the traffic
through the networks which from the Internet, the
routers, direct the packets through available channels.
If one channel becomes congested with data, the data is
routed through another. Because each packet has an
address on it, no matter which channel it passes
through, it can always travel to the correct computer.
The packets rarely arrive in the order in which they
were sent. For example, packets that travel to the USA
via England will take longer than others that are
directed through other routers. The time difference
may be in the thousandths of seconds but it matters.
TCP is used by the Internet to control this problem.
This protocol keeps a record of the data’s original
order and as the packets arrive, TCP puts them back
into the correct order. TCP also checks for errors in
Topic 11: The Internet and World Wide Web
Figure 11.4 Internet Communications
Data travels through the Internet in the form of packets of data
containing parts of the message and the destination address.
a. IP Addresses
Each computer, when it connects to the Internet, has a
unique address assigned to it. The address is
comprised of 4 numbers in the range 0-255 connected
by periods. eg. 230.345.100.054. This is known as the
IP (Internet Protocol) address. All Web servers have a
fixed IP address and this address provides the means
by which they can be accessed.
When a personal computer is connected to the Internet,
it is allocated a dynamic IP address by which it can be
accessed by other machines. In this way, at any time,
all computers on the Internet have unique addresses to
enable others to communicate with them.
b. Domain Names
To make life easy for people who can’t remember
numbers, people can register Domain Names, for
example, company names or university names against
these numbers. For email access and Web access, we
don’t have to remember numbers but words. An email
address might be john.oneill@bigpond.com and a Web
address might be www.bigpond.com. In both cases the
addresses name the server which is to be used and
every named server has a unique IP address. Special
computers on the Internet, called Domain Name
Servers, store the myriad of domain names and their IP
addresses. When a user enters a domain name, its IP
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address is quickly discovered when it is automatically
looked up on the nearest Domain Name Server (DNS).
11.5 Email
When a person on the Internet uses a mail package to
send an email, the email is addressed to a person using
a common format of address person@server, for
example bill_hughes@bigpond.com As the email is
sent, the DNS is looked up to discover the IP address
of the server and the message is sent to that server.
When the intended recipient logs into their email, the
message is downloaded to them. The server knows
which message goes to which person because each
message is addressed to a person.
Figure 11.5: email
an email system showing the mail servers
11.6 Web Servers
The World Wide Web is a collection of Web servers
connected to the Internet. Web servers contain a
variety of resources that have been organised in a way
that enables other users on the Web to download them.
In this way, the Web represents a vast network of
resource sharing computers.
The Web consists of a large number of servers which
contain the Web content and a large number of users
whose computers run Web browsers eg. Internet
Explorer. When a person uses his computer to access
the Web, he or she enters the Web address of the server
to be accessed and the browser downloads the main
page (Home Page) from that server. The main page
typically contains links to a variety of resources
contained within the server that has been accessed.
a. Web Functions
The Web supports a number of different forms of
activities for users and it is this flexibility and
functionality that makes the Web the useful application
that it is.
Table 11.1: functions supported by the Internet and
Web
Function
Description
Information
access
Web pages can be used to share
information globally and instantaneously. A
Web page on a server anywhere in the
world can be accessed in a fraction of the
time by other computers on the Web.
Multimedia
The Web can display media of many forms
including images, photographs, audio,
videos and 3 dimensional images
Topic 11: The Internet and World Wide Web
Document
sharing
The Web can be used to upload and
download documents between computers
and servers. A word document of one
computer can be uploaded to the server
and downloaded to another’s computer.
Data
streaming
Data from a Web server can be streamed
continuously to other computers on the
Web. In this way, people can listen to radio
over the Web, can view videos over the
Web and since the data can stream in 2
ways, the Web supports videoconferencing
and audioconferencing.
Database
activities
The Web can be used to provide users with
access to vast amounts of information
stored on databases. Users can view this
information and can often upload
information to databases.
b. Web Services
With all these capabilities, the Web is used for a
variety of applications that serve many useful
functions. The Web is now used frequently for such
activities as:
Home Banking. The Web enables customers to
connect to their banks and to conduct such banking
transactions online as bill-paying, funds transfer,
account reconciliation etc. More and more people are
using this facility to keep track of all their financial
transactions.
Stocks and Shares, The Web enables people to
monitor the share markets across the world and to buy
and sell shares online. The online facility provides
instant access to stock information and the capability to
buy and sell at the touch of a button (and without the
need for a stock-broker!).
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Figure 11.6 financial applications on the Web
http://www.asx..com.au
Australian Stock Exchange
Online Shopping. There are now many vendors who
offer the capacity for people to buy goods and services
online across the Web. The customer browses through
the online catalogue and places things into the virtual
shopping basket before charging them to a credit card
to effect the purchase. Online shopping has become
quite popular especially with products which are hard
to find. On the Internet and the Web, the shopping
opportunities are worldwide.
Figure 11.8: online learning
http://flexiblelearning.net.au
online learning resources
There are a myriad of other ways in which people can
now use the Internet and Web. There are online
auctions, online movies and online information of
many types.
Figure 11.7: Online shopping
http://fragrancenet.com
Online perfume shopping
Online learning. Many people use the Internet and
Web these days to access their learning materials and
online courseware. Online learning provides many
opportunities and advantages as a support for
conventional learning and as a means to study at a
distance. Learners use the Web as a source of
information and also as a means of communication to
talk with the teachers and other students.
Topic 11: The Internet and World Wide Web
Figure 11.9: Airline tracking
At Flytecomm, users can enter the airline and flight
number and view the current position of the plane with
flight details sourced from a flight tracking database. The
page updates the image every 5 minutes.
http://www.flytecomm.com
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11.7 Web Browsers
A Web browser is a piece of software that runs on a
computer with Internet connectivity. It allows the user
to access information from Web sites worldwide. The
browser software facilitates the connection between a
person’s computer, their Internet Service Provider
(ISP) and the network which is the World Wide Web.
to record a Web page so that it can be visited at a later
date. The bookmarks can usually be organised into
folders and files so they can be found again. History
links show all the links that have been previously
visited, a useful feature when trying to relocate a page
after the link has been disconnected.
Fig 11.11: Internet Explorer Navigation
A page showing the navigation links as they appear in IE 5.
b. Display Options and Preferences
Fig 11.10: How the Web works
http://www.thebeehive.org
Browsers come in many shapes and sizes and although
they share the same basic functionality, different
browsers offer different features to users. The most
popular browsers include Internet Explorer, Netscape
Navigator, Safari, Mozilla Firefox, and Opera.
Browsers offer a range of standard functions which
include:
• Navigation facilities;
• Bookmarks and History links;
• Display Options;
• Personalised features
There are a many display options and preferences that
can usually be set by users within their Internet
browsers. The display options enable fonts and font
sizes to be set, the various menus to be displayed, even
the colour of the browser.
Personalised Features
As more and more people use the Web, the browsers
are becoming more and more clever in terms of the
supports they can provide to users. A very useful
personalised option most browsers provide is auto form
fill. When a user is required to fill a form with name
and address etc, the browser can prompt with preset
items eg. name, address etc. This can be a very useful
time saving feature when used.
a. Navigation Options
The navigation options in most browsers provide the
facility for the user to go backwards through the Web
pages that have been visited and to go forwards to the
most recent page. If a page is taking too long to
download, it can be stopped. The browser can be made
to refresh the current page or to return to the user’s
nominated Home Page. Among the navigation
features, browsers can show the Uniform Resource
Locator of the current page and those of the links on
the current page.
Bookmarks and History Links
Browsers have features that enable users to store
bookmarks in the form of links to visited pages.
Bookmarks, as the name suggests, are able to be used
Topic 11: The Internet and World Wide Web
Fig 11.12 Auto Forms Fill
A page showing some settings for auto forms fill in IE 5.
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Links of Interest and Relevance
Topic 11: Test Your Knowledge
http://www.economist.co.uk/printedition/PrinterFriendl
y.cfm?Story_ID=3172188
How Googles Pagerank system works
1. What is meant by the term backbone in the context
of a computer network? Give an example.
http://www.w3.org/
The World Wide Web Consortium (W3C) develops
interoperable technologies (specifications, guidelines,
software, and tools) to lead the Web to its full
potential. W3C is a forum for information, commerce,
communication, and collective understanding.
2. Describe how data is transferred between
computers on the Internet.
3. What is TCP/IP? How does it work?
4. What is an IP address? Use an example to describe
how IP addresses are used.
http://www.lib.berkeley.edu/TeachingLib/Guides/Inter
net/Glossary.html
Glossary of Internet & Web Jargon
5. What is a domain name? Give some examples of
common domain names and strategies that can be
used to guess domain names.
http://www.webopedia.com/
Webopedia - an online dictionary and search engine for
your computer and Internet technology definitions.
6. What is a URL? How are they used
http://www.learnthenet.com/english/html/70alan.htm
Under the Hood of the World Wide Web
8. Explain the difference between a Web server and a
Web browser.
http://www.learnthenet.com/english/html/13wworks.ht
m
How the Web Works
9. List the different types of functions supported by
the Internet and WWW.
http://www.cio.com/WebMaster/sem2_home.html
An overview of the World Wide Web
7. Describe how the WWW works.
10. What is a browser plug-in? Describe how a plugin works.
http://www.isoc.org/internet/history/brief.shtml
A Brief History of the Internet
http://about-the-web.com/
An internet guide for newcomers to the World Wide
Web
http://www.private.org.il/harvest.html
How do spammers harvest email addresses?
http://websearch.about.com/od/whatistheinternet/a/hist
oryinternet.htm
A Brief History of the Internet - To understand the
Internet, it's a good idea to look at its' history.
Topic 11: The Internet and World Wide Web
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