The fundamental concepts of the Internet, its origin, services provided and how to access it

1. INTRODUCTION TO THE INTERNET

2.  The Meaning of the Internet
◦ The Internet is a global network of interconnected
networks of computers.
◦ The computers are connected via a huge network of
telecommunications links.
◦ The Internet allows you access to a whole resource
of data and information stored at different sites
(called hosts or servers)
◦ hosts /servers are at locations all around the world.

3.  The Meaning of the Internet
◦ The communication links that interconnect each
host computer use a common method of
transmission
 known as TCP/IP
◦ TCP/IP stands for Transmission Control
Protocol/Internet Protocol.
◦ Devices such as routers, bridges and switches are
used in one way or the other to connect one
network to the other.

4.  The Meaning of the Internet
◦ Networks connect to each other at various public or
private connection points, called peering points.
◦ Public peering points are called Network Access
Points (NAPs)
◦ Private peering points follow Acceptable Use
Practices (AUP)
◦ Each computer connected to the Internet can act as
a host or client.

5.  The Meaning of the Internet
◦ A host computer provides information for other
people to access and retrieve
◦ A client computer accesses information from a host
computer on the Internet
◦ The size, scope and design of the Internet allow
users to:
 Connect easily through ordinary personal computers
and local phone numbers
 Exchange electronic mail with friends and colleagues
with accounts on the Internet

6.  The Meaning of the Internet
◦ Post information for others to access, and update it
frequently
◦ access multimedia information that includes sound,
photographic images and even video
◦ Access diverse perspectives from around the world

7.  History of the Internet
◦ The Internet had its origins in the cold war between
Russia and America in the 1960's.
◦ The US air force first and foremost introduced
Internet.
◦ The idea was to enable the forces communicate
through interconnected computers from different
geographical locations, especially during war.

8.  History of the Internet
◦ The RAND corporation proposed a system with no
centralized authority
 As any centralized system would be a target of any
possible attack
◦ The proposed system, developed by Paul Baran,
suggested a decentralized system that would still
operate even if parts of it were destroyed

9.  History of the Internet
◦ Each node decides how to send the packet to the
next available node.
◦ Even if some nodes were destroyed, the message
could still be sent by an alternative route.
◦ In this way, the network would withstand a nuclear
strike.
◦ After implementing the network, it was known as
ARPANET (the Advanced Research Projects Agency
Network)

10.  History of the Internet
◦ The network was used by the US military and US
universities.
◦ Gradually, as more and more connections were
made, it has evolved to the present day Internet.

11.  Uses of the Internet - Obviously, the Internet
can bring you a whole host of capabilities.
Among the ways that users like you are
taking advantage of the Internet are:
◦ Sharing research and business data among
colleagues and like-minded individuals
◦ Communicating with others and transmitting files
via E-mail

12.  Uses of the Internet
◦ Requesting and providing assistance with problems
and questions
◦ Marketing and publicizing products and services.
◦ Gathering valuable feedback and suggestions from
customers and business partners
 NB: The Internet's potential is limited only by users'
vision and creativity

13.  The Components of the Internet - The
Internet consist of a number of computers
called hosts and interconnecting equipment
◦ Four Major Components of the Internet Identified:
 Hardware (Devices) E.g. Computers, routers, and
modem
 Transmission media: (Telecommunication links)

14.  The Components of the Internet
◦ Software: The internal instructions used by
computers to do their job correctly
◦ Protocol: The standard language for communication
by devices on a network (Internet) e.g. TCP/IP,
SMTP, POP, etc)

15.  More on the Components of the Internet:
◦ A host is a computer on the Internet capable of
acting as a provider of information, such as files,
documents or images.
◦ A client is a computer that connects to the Internet
to access information from a host or server
computer.
◦ A network interface is a device that connects a
client computer, server, printer or other component
to your network.

16.  More on the Components of the Internet:
◦ Domain Names and TCP/IP Address - Each host
computer is identified in two ways
 Firstly, each computer on the Internet has a unique
assigned name, such as host1.cit.ac.nz which is
referred to as its domain name.
 Secondly, each computer on the Internet also has a
unique numerical address, called a TCP/IP address.
 Example, the computer known as host1.cit.ac.nz could
have a TCP/IP address of 156.59.20.49

17.  Network Topology - Topology refers to the
way in which the network of computers is
connected.
◦ Each topology is suited to specific tasks and has its
own advantages and disadvantages.

18.  Network Topology
◦ The choice of topology is dependent upon
 type and number of equipment being used
 planned applications and rate of data transfers
 required response times
 cost

19.  Network Topology
◦ There are FOUR major competing topologies
 Bus - all workstations (computers) are connect to the
same cable segment
 Ring - workstations connect to the ring
 Star - all wiring is done from a central point (the
server or hub)
 FDDI (Fiber Distributed Data Interface) - FDDI is based
on two counter rotating 100-Mbit/sec token-passing
rings.

20.  Network Topology

21.  Services or features provided by the Internet
◦ E-mail, for exchange of electronic mail messages.
◦ USENET newsgroups, for posting and responding to
public "bulletin board" messages.
◦ File Transfer Protocol (FTP), a system for
transmission, storing and retrieving data files on
large computer systems.

22.  Services or features provided by the Internet
◦ Gopher, a method of searching for various text-
based Internet resources (largely obsolete).
◦ TELNET, a way of connecting directly to computer
systems on the Internet.
◦ Internet Relay Chat (IRC), a system for sending
public and private messages to other users in "real
time"

23.  Services or features provided by the Internet
◦ CU-SeeMe, a videoconferencing system that allows
users to send and receive sound and pictures
simultaneously over the Internet.
◦ The World Wide Web.
◦ The final component listed here is perhaps the
most exciting element of the Internet today.

24.  The World Wide Web (WWW) - The World Wide
Web is a collection of web pages on host
machines which deliver documents, graphics
and multi-media to users via the Internet.
◦ This is the part of the Internet you can access with
your web browser
◦ WWW or web for short, consists of millions of web
sites (like yahoo.com, microsoft.com, and
davesite.com) and millions of web pages.

25.  Functions of the WWW
◦ The WWW allow users to link documents together
using clickable links.
◦ A browser (viewing application that displays web
pages) is used to view the content that server
computers provide.
◦ This browser automatically displays the documents
correctly formatted along with the graphic images
or additional multimedia components that the
author of the page wishes to incorporate.

26.  Getting access to the Internet - Each user can
access the Internet through connection on an
existing network or via a modem
◦ Modem is a device that allows the computer to use
a telephone line to connect to a remote network or
ISP)
◦

27.  Internet Service Providers (ISP's) are
companies which provide you with access to
the Internet.
◦ Examples include: America-On-Line, Yahoo,
Google, Prodigy, Africa-On-Line, and UCOM.
◦ ISPs are classified into three tiers, based on size
and capacity:

28.  Methods of connecting to the Internet:
◦ Dial-up connection using a modem and a telephone
line.
◦ Dedicated connections
 Broad band connections – Satellite dish is required.
The bandwidth is not fixed.
 Leased or fixed lines – Fixed permanent connection
with fixed bandwidth and constant speed (satellite dish
required).
 OC – High speed connection with very huge bandwidth
(Satellite dish required)

29.  Methods of connecting to the Internet:
◦ Using Digital Subscriber Line (DSL)
◦ Using Wireless Devices such as wireless modem e.g.
Vodafone USB modem and Expresso USB wireless
modem

30.  Internet Technologies - Internet
Technologies refers to a collection of
protocols and applications that drive the
Internet.
◦ A protocols refer to a set of rules that enables
devices interconnected on a network to
communicate.
◦ Applications are software that run on the Internet.

31.  Internet Technologies
◦ Examples of Internet Technologies
 TCP/ IP - Transmission Control Protocol/Internet
Protocol – The underling or fundamental protocols
(language) used by computers to communicate on the
Internet.
 It is responsible for the transport of packets (chunks) of
data from one network to the other.

32.  Internet Technologies
◦ Examples of Internet Technologies
 FTP - File Transfer protocol – Controls the transfer of
file from one network to another.
 HTTP - Hyper Text Transfer Protocol – used in
requesting and transfer of web pages from a web
server by a client computer
 HTML/XML - Hyper text Markup Language/Extended
Markup Language – the underlying languages for web
page development and data presentation.

33.  Internet Technologies
◦ Examples of Internet Technologies
 SMTP - Simple Message Transfer Protocol - for e-mail
 POP – Post Office Protocol - for e-mail
 Database Servers – Database management software
(DBMS) that runs on the host/server computer.
Examples: WampServer and IIS (Internet Information
Server)

34.  Domain names
Servers or host computers are arranged
according to geographical location. For
instance, all countries in the world have a
country suffix, except the USA. Ghana’s suffix
is gh, while United Kingdom's is uk. Typically,
the structure of domain name of a host
computer follows this format:

35.  Domain names - Typically, the structure of
domain name of a host computer follows this
format:
◦ server name
◦ organization name
◦ type of organization
◦ country name

36.  Domain names
◦ For instance, the Internet address such as
www.waec.ac.gh defines it as a host called
 www, belonging to an organization called waec,
 which is an academic institution (ac stands for
academic)
 located in Ghana (gh stands for Ghana).

37.  .Web Browsers - . A web browser is a
software application that interprets
documents that you request from a web
server on the WWW and displays them for you
to view
◦ Two common types of web browsers are Netscape
Navigator and Internet Explorer.

38.  How Web Servers Work

39.  Hyper-Link
A hyperlink is a clickable link to another
document or resource. It is normally shown in
blue underline. When a user clicks on a
hyperlink, the client will retrieve the
document associated with that link, by
requesting the document from the designated
server upon which the document resides
 NB: Behind every hyper-link is a URL

40.  URL - A Uniform Resource Locater is a means
of specifying the pathname for any resource
on the Internet. It consists of three parts
◦ a protocol part
◦ a host part
◦ a document name

41.  URL
◦ For instance, the following URL;
http://www.waec.ac.gh/wassce/2007result.htm
specifies the protocol as http,
◦ the host or WWW server as www.waec.ac.gh and
◦ the document as /wassce/2007result.htm.

42.  Search Engines and Finding Information on
the Internet:
◦ What is a search engine?
A search engine is a program that serves as a
means of searching for information that can be
found on the Internet.
◦ To search for information on the Internet, you need
a keyword about what you want.
◦ Type the keyword in a search box and click search
or press enter.
◦ Examples: google, yahoo, altavista, dogpile,
webcrawler etc

43.  How a search engine works
When a user accesses a search engine, they are
presented with a graphical interface form, on
which they specify what they are looking for.
When they tell the search engine to start the
search (by pressing "enter" or clicking on a
specific button), the search engine invokes a
program that queries its database (a collection of
all the web pages it has access to).
 The results are returned to the user as a number
of possible URL's.

44.  What is a web page?
A web page is a simple text document that
contains information (text, images, sound,
video and links) to be displayed and
instructions on how to format that
information on the screen.
◦ The format instructions are called HTML (hypertext
mark-up language) tags, and are simple
instructions that inform the web browser as to how
the information should be displayed.

45.  Rules and regulations governing the use of the
Internet
 The Internet is just like a world on its own,
having rules and regulations that control the
activities that go on there.

 Netiquette
Netiquette simply means online conduct. It is
how you or others behave online. One of the
problems with the Internet is sometimes you
could pretend to be someone else, and mislead
people.

46.  Bits, Bytes and Bandwidth
In this section you will learn about bits, bytes
and bandwidth.

 Bits
A computer stores information in digital
format as a series of ‘on’ and ‘off’ states,
called logic 1's and logic 0's. The smallest
element of information in a computer is a bit,
and has digital representation of (can hold)
either 1 or 0.

47.  Bytes
Obviously, a computer using only one bit can
hold two states, either 1 or 0. This is not
practical for handling a lot of information! So,
more than one bit is grouped together. A Byte
is actually a grouping of 8 bits, and thus as a
whole can hold 256 possible values. A
computer uses a byte to hold characters,
such as the character 'A' , the digit '3' or the
symbol '*'

48.  Searching for information on the internet
 Copying document from the web into another
application
 Saving web page onto the local drive
 Adding web page to favorite
 Bookmarking web page
 Different b/n bookmarking/favorite and
saving web pages
 Downloading file from the Internet
 Saving picture from the Internet onto the
local disc (eg desktop)