Planning for teaching, Internet, importance of internet, network, some important reasons for networking, applications of network, benefits of network, types of network, entering URL, Navigation buttons, browsing internet, uniform resource locator, email, email address, parts of mail, attach files to message, email features

1. INTERNET
By
Dr. I. Uma Maheswari
iuma_maheswari@yahoo.co.in

2. • Several networks, small and big all over the
world, are connected together to form a Global
network called the Internet.
• Today’s Internet is a network of about 50 million
or more computers spread across 200 countries.
• Anyone connected to the Internet can reach,
communicate and access information from any
other computer connected to it.

3. Importance of Internet
• Research: The web provides research materials
from libraries, research institutions,
encyclopedia, magazines and newspapers.
Some sample sites www.encarta.com the
Internet Public Library site www.ipl.com and
Library of Congress www.loc.gov.
• Chatting: Some websites proved chat rooms to
interact with an individual or a group.
• Free-wares: Some sites provide free download
of software’s, tutorials and benchmarks.

4. • Education online: Educational institutions offer
courses via the web. Student can attend and
interact in a class from home using a computer.
• Online services: Online shopping, online
booking for travels and entertainments
managing investments are the upcoming areas
of Internet that reaches every home.
• Job searches: The digital revolution is
changing everything it touches and the job
market is no exception. Several web sites are
assisting people in finding internship, jobs and
helps companies to fill job vacancies. There are
sites relating to specific job and profession also.
Some of these sites charge a fee for the
services while others are free.

5. Network
• A large number of computers are
interconnected by copper wire, fiber optic
cable, microwave and infrared or through
satellite.
• A system consisting of connected nodes
made to share data, hardware and
software is called a Computer Network.

6. Some Important Reasons for
Networking
• Sharing of resources:
– Primary goal of a computer network is to share resources. For
example several PCs can be connected to a single expensive
line printer.
• Sharing information:
– Information on a single computer can be accessed by other
computers in the network. Duplication of data file on separate
PCs can be avoided.
• Communication:
– When several PCs are connected to each other, messages can
be sent and received. From a remote location, a mobile
salesman can relay important messages to the central office
regarding orders. Relevant databases are updated and the
business commitments are fulfilled.

7. Applications of Network
• Electronic data interchange
• Tele-conferencing
• Cellular telephone
• Cable Television
• Financial services, marketing and sales
• Reservation of Airlines, trains, Theatres and
buses
• Telemedicine
• ATM
• Internet banking

8. Benefits of Network
• Effective handling of personal
communications
• Allowing several users to access
simultaneously Important programs and
data:
• Making it easy for the users to keep all
critical data on shared storage device and
safeguard the data.
• Allowing people to share costly equipment.

9. The computer communication should ensure safe,
secure and reliable data transfer.
• Safe : The data received is the same as the data
sent.
• Secure : The data being transferred cannot be
damaged either will fully or accidentally.
• Reliable: Both the sender and the receiver
knows the status of the data sent. Thus the
sender knows whether the receiver got the
correct data or not.

10. Types of Network
• Local Area Network (LAN)
• Metropolitan Area Network (MAN)
• Wide Area Network (WAN)

11. Local Area Network
• A network connecting systems and devices inside a
single building or buildings close to each other is called
Local Area Network (LAN)
• Generally LANs do not use the telephone network.
• They are connected either by wire or wireless.
• Wired connection may be using twisted pairs, coaxial
cables or Fiber Optic cables.
• In a wireless LAN, connections may be using infrared or
radio waves.
• Wireless networks are useful when computers are
portable.
• Wireless network communicates slowly than a wired
network.

13. • The number of Computers in the network is
between two to several hundreds.
• LAN is generally used to share hardware,
software and data.
• A computer sharing software package and hard
disk is called a file server or network server.
• A Network that spans a geographical area
covering a Metropolitan city is called
Metropolitan Area Network (MAN).
• A WAN is typically two or more LANs connected
together across a wide geographical area.
• The individual LANs separated by large
distances may be connected by dedicated links,
fiber optic cables or satellite links.

14. Metropolitan Area Networks
(MANs)
• The network size falls intermediate between
LANs and WANs. A MAN typically covers an
area of between 5 and 50 km diameter. Many
MANs cover an area the size of a city, although
in some cases MANs may be as small as a
group of buildings or as large as the North of
Scotland.
• A MAN (like a WAN) is not generally owned by
a single organisation.

15. • The MAN, its communications links and
equipment are generally owned by either a
consortium of users or by a single network
provider who sells the service to the users. This
level of service provided to each user must
therefore be negotiated with the MAN operator,
and some performance guarantees are normally
specified.
• A MAN often acts as a high speed network to
allow sharing of regional resources (similar to a
large LAN).
• It is also frequently used to provide a shared
connection to other networks using a link to a
WAN.

16. • A typical use of MANs to provide shared
access to a wide area network

17. Wide Area Network (WAN)
• The information traveling on your wide
area network (WAN) traverses longer
distances and encounters a wider variety
of physical and logical environments en
route.
• WAN technologies, including 56 Kbps
circuits, ISDN, leased lines, and frame
relay, are optimized for these lengthy
journeys.

18. World Wide Web
• Web is a multimedia portion of the
Internet.
• It consists of an interconnection system of
sites or servers all over the world that can
store information in the multimedia form.
• The Multimedia sites include text,
animated graph, voice and images.
• The World Wide Web is the most
graphically inviting and easily navigable
section of the Internet.

19. • The World Wide Web contains several
millions of pages of information. Each
page is called a web page.
• A group of related web pages linked
together forms a web site.
• The first page of the website is called a
Home page.
• The Home page usually contains
information about the site and links to
other pages on that site.

20. Getting connected to Internet
To use an Internet in the simplest way, we need
• A Computer
• A Telephone line
• A Modem
• Internet Service Provided or ISP

21. The ISPs are the companies which allows the user to use
the Internet for a price. One has to register with the ISP
for an Internet account. ISP provides the following:
• User name - An unique name that identifies the user
• Password - A secret code that prevents other users from
using your account
• E-mail address - Unique address that you can send or
receive E-mails.
• Access telephone number - Internet users can use this
number to connect to the service provider.

22. • The figure shows dialog boxes on the computer screen
wherein the user name, a password (alpha numeric of
word length 8 characters appearing as ‘x’) and access
telephone number are entered. By clicking on the dial
button, the modem establishes a connection with the
ISP.
Dialogue Box for Connecting to the Internet

23. • There are two ways to look for the
information on the Web.
• If the URL of the website is known, enter it
on the address bar.
• If URL is not known, then ‘Search Engines’
will help us to get the information.
• Search Engines are tools that allow the
user to find specific document through key
words or menu choices.
• Some of the popular Search engines are
Yahoo, Lycos, AltaVista, Hotbot , Google
and Askjeeves.

24. Entering the URL
Back button
Forward button:
Stop button:
Refresh button
Home button

25. Navigation Buttons
Internet explorer helps to use the net more
effectively with the navigation buttons on the
toolbar.
1. Back button: This button helps to go back to the
previous link. The small triangle adjacent to it
displays a dropdown list of several recently used
pages. Instead of pressing the back button
several times, select a page from the list.
2. Forward button: This is a similar to the back
button. One can jump forward by one page or
several pages.

26. 3. Stop button: After clicking on a link, some
times we may realize that the link is not
necessary. The click stop button and move back
without wasting time.
4. Refresh button: Sometimes a page may take
longer time or may not load properly. Click on
the refresh button, helps reload the page faster.
5. Home button: While following the hyperlink, it is
very easy to get lost. The home button reverts to
the home page of the website.

27. Browsing the Internet
• Searching the information from the Internet is
called as browsing the internet.
• Browsing is also called as surfing.
• Browsing can be down with the help of browsing
software.
• Internet explorer, Netscape Navigator etc are
some of the browsing softwares.

28. URL – Uniform Resource Locator
• http:/www.yahoo.com
• http – Hyper Text Transfer Protocol
• www – World wide web
• Yahoo – search engine
• Com - Commercial

29. E - mail
• E–mail is much faster than old – fashioned
mail, called ‘snail mail’.
• An e–mail message can travel around the
world in minutes.
• Once you pay a service provider for a
connection to the internet, there is no
charge for sending and receiving e-mail.
• Exchanging e-mail can save you money
on long distance calls.

30. E-mail Address
• An e-mail address defines the location of the
individual’s mailbox on the internet.
• An email consists of two parts separated by the
@ (“at”) symbol.
• An email address cannot contain spaces.
– The user name is the name of the person’s account.
This can be a real name or a nick name.
– The domain name is the location of the person’s
account on the internet. Period (.) separate the
various parts of the domain.
– Eg tcp@yahoo.com

31. Parts of a message
• From : Address of the person sending the
message
• To : Address of the person receiving the message.
• Subject : Identifies the contents of the message.
Make sure your subject is informative.
• Cc : A carbon copy is an exact copy of a
message.
• Bcc : A Blind carbon copy which lets you send the
same message to several people without them
knowing that others have also received the same
message

32. Attach files to messages
• We can attach document, pictures, sound,
video or program to a message we are
sending.
• Compress attached files

33. E-mail Features
• Receive messages:
– we do have to be at our computer to receive a
message.
– Service provider keeps all our messages until
we retrieve them.
• Forward a message
– After reading a message, we can add
comments and then send the message to a
friend or colleague.

34. • Print a message
– We can print a message to produce a paper
copy.
• Organize messages
– Email programs usually store messages we
have sent, received and deleted in separate
folders which helps us to keep messages
organized so we can review them later.