Computer networks allow devices to exchange data by passing packets of information between nodes through connections. The earliest computer networks were developed in the 1960s to allow computers to share resources more efficiently. The best known computer network today is the Internet, which originated from ARPANET and has evolved from connecting universities to becoming a global network relying on TCP/IP protocols.

2. Computer Networking
• A computer network or data network is
a telecommunications network that
allows computers to exchange data.
• In computer networks, networked computing
devices pass data to each other along data
connections.
• Data is transferred in the form of packets. The
connections (network links) between nodes are
established using either cable media or wireless
media.
• The best-known computer network is the Internet.

3. Making devices talk to each other for the
purposes of communication is nothing new. Early
forays into telephony such as the telegraph and
telephone have since evolved
into more complicated devices, and now a
computer can be networked to the Internet, another
PC, or even a home stereo.
In the early 1960s, individual computers had
to be physically shared, making the sharing of data
and other information difficult. Seeing this was
impractical, researchers developed a way to
“connect” the computers so they could share their
resources more efficiently. Hence, the early
computer network was born.

4. Brief History
of Networking

5. History: Networking
• 1961: Kleinrock - queuing theory shows
effectiveness of packet-switching
• 1964: Baran - packet-switching in military
applications for survivable networks
• 1967: ARPAnet conceived by Advanced Research
Projects Agency

6. History: Networking
• 1969: First ARPAnet node operational
– Prof.Kleinrock sends a message across from
UCLA to Stanford
• 1972:
–ARPAnet demonstrated publicly
–NCP (Network Control Protocol) first host-host
protocol
– First e-mail program
–ARPAnet has 15 nodes

7. History: Networking
• Time sharing became difficult since different machines
had different operating systems, versions and programs
–however, these led to development of Internet
• Vinton Cerf. Bob Kahn, Bob Braden and Jon Pestel
developed TCP/IP
• Cerf and Kahn’s internetworking principles:
– minimalism, autonomy - no internal changes required
to interconnect networks
– best effort service model
– stateless routers
– decentralized control define today’s Internet
architecture

8. History: Networking
• 1978: TCP/IP v4 was released
– Aimed to interconnect different kinds of networks
• 1979: ARPAnet has 200 nodes
• 1983: deployment of TCP/IP in ARPAnet
• 1983: SMTP e-mail protocol defined
• 1983: DNS defined for name-to-IP-address
translation
• 1985: FTP protocol defined
• 1988: TCP congestion control
100,000 hosts connected to confederation of networks

9. History: Networking
• 1970: ALOHAnet satellite network in Hawaii
(CSMA developed), later connects to ARPANet
• 1973: Bob Metcalfe’s PhD thesis proposes
Ethernet (CSMA/CD developed)
• 1974: Cerf and Kahn - architecture for
interconnecting networks: the word “Internet”
makes its appearance from Cerf’s writings

10. History: Networking
• Early 1990’s: ARPAnet decommissioned
• Early 1990s:WWW
– Hypertext (1945 Bush: “As We May Think” article, Ted
Nelson, Engelbert, Andries in 1968 )
– HTTP: Tim Berners-Lee develops WWW an Internet based
hypermedia initiative at CERN, specifies URLs, HTTP and
HTML which became basis for today’sWWW
– 1994: Mosaic (Univ. of Illinois), later Netscape the major
browsers until late 1990’s
– late 1990’s: commercialization of the WWW, with introduction
of HTTPS e-commerce is realized
Late 1990’s:
• est. 50 million computers on Internet
• est. 100 million+ users
• backbone links running at 1 Gbps

11. What is Internet?
• Worldwide collection of networks,
gateways, servers and computers using a
common set of telecommunication
protocols to link them together.
• It is a system connecting millions of
computers around the world. Which also
known as information super highway.

12. 1960’s US government seeks nuclear war proof
communications, briefs project to ARPA
1969 Universities and researches connected to ARPAnet
1977 ARPAnet engineers realize the network is going to
grow beyond expectations
1983 ARPAnet switched to TCP/IP
1989 Tim Berners-Lee proposes a new set of Internet
protocols
1995 US government releases Internet
for commercial use

13. Ethical rules for Computer Users
Some of the rules that individuals should
follow while using a computer are listed
below:
o Do not use computers to harm other
users
o Do not use computers to steal others
information
o Do not access files without the
permission of the owner

14. o Do not copy copyrighted software
without the author’s permission.
o Always respect copyright laws and
policies.

15. o Complain about illegal communication and activities,
if found, to Internet service Providers and local law
enforcement authorities
o Users are responsible for safeguarding their User ID
and Passwords. They should not write them on
paper or anywhere else for remembrance
o Users should not intentionally use the computers to
retrieve or modify the information of others, which
may include password information, files, etc..

16. o Respect the privacy of others, just as you expect
the same from others
o Do not use other user's computer resources
without their permission
o Use Internet ethically

17. Internet Ethics
Internet Ethics - means acceptable behavior for
using internet. We should be honest, respect the
rights and property of others on the internet.
Acceptance
One has to accept that Internet is not a value free-zone
.It means World Wide Web is a place where values
are considered in the broadest sense so we must
take care while shaping content and services and we
should recognize that internet is not apart from universal
society but it is a primary component of it.

18. Sensitivity to National and Local Cultures
It belongs to all and there is no barrier of national
and local cultures. It cannot be subject to one set of
values like the local TV channel or the local
newspaper We have to accommodate multiplicity of
usage.
While using e-Mail and chatting
Internet must be used for communication with family
and friends. Avoid chatting with strangers and
forwarding e-mails from unknown people /strangers. And
we must teach children about risks involved in chatting
and forwarding e-mails to strangers.

19. Pretending to be someone else
We must not use internet to fool others by pretending
to be someone else. Hiding our own identity to fool
others in the Internet world is a crime and may also be a
risk to others. It’s our responsibility to teach
children the same.
Avoid Bad language
We must not use rude or bad language while using e-mail,
chatting, blogging and social networking, We need
to respect their views and should not criticize anyone
on the internet and the same should be taught to
children.

20. Hide personal information
We should teach children not to give personal details
like home address, phone numbers, interests, passwords. No
photographs should be sent to strangers and they should be
asked to hide their personal details from strangers because it
might be misused and shared with others without their
knowledge.
While Downloading
Internet is used to listen and learn about music , It is also
used to watch videos and play games We must not use it
to download them or share copyrighted material. The same
should be taught to children, and they must be aware of the
importance of copyrights and issues of copyright.

21. Supervision
You should know what children are doing on the
internet and the sites they visit on the internet and
should check with whom they are communicating.
Restrict them browsing inappropriate sites. Parental
involvement is essential when a child is using the
internet in order to make him follow the rules.
Encourage children to use Internet
We must encourage children, students and
others to gain the knowledge from the internet and use
it wisely. Internet is a great tool where we can gather
information which can be used for learning.

22. Access to Internet
The internet is a time-efficient tool for everyone that
enlarges the possibilities for curriculum growth.
Learning depends on the ability to find relevant and
reliable information quickly and easily, and to select, understand
and assess that information. Searching for information on the
internet can help to develop these skills.
Classroom exercises and take-home assessment tasks,
where students are required to compare website content, are
ideal for alerting students to the requirements of writing for
different audiences, the purpose of particular content,
identifying and judging accuracy and reliability.
Since many sites adopt particular views about issues, the
internet is a useful tool for developing the skills of distinguishing
fact from opinion and exploring subjectivity and objectivity.

23. Internet, Intranet and
Extranets

24. What is Internet ?
• It is a Global network of computers, (servers or clients).
to exchange information.
• It is a "network of networks" that includes millions of
private and public, academic, business, and government
networks (local or Global),
linked by copper wires, wireless connections, and other
technologies.

25. Hardware and Software of Internet
Variety of hardware and software are used to make
Internet functional.
• Modem
Device that enables computers to communicate
through phone lines.
When we start internet the our modem communicates
to modem of ISP.

26. • Computer
Continued…
In addition to a modem, you need a client capable of
handling multiple data types.
• Software
Two types of software’s required to enable your PC as an
Internet PC.
• Communication software to establish connection
• Client software for browsing, e-mail, news.
these software’s are provided with windows itself.

27. Applications Of Internet
• Download programs and files
• E-Mail
• Voice and Video Conferencing
• E-Commerce
• File Sharing
• Information browsing
• Search the web addresses for access through search engine
• Chatting and many more…

28. Disadvantages of Internet
• Theft of personal information such as name, address, credit card
number etc.
• Virus threats nothing but a program which disrupts the normal
functioning of your system.
• Spamming refers to receiving unwanted e-mails in bulk, which
provide no purpose and needlessly obstruct the entire system.
• Pornography This is perhaps the biggest threat related to children’s
healthy mental life. A very serious issue concerning the Internet.
Though, internet can also create havoc, destruction and
its misuse can be very fatal,
the advantages of it outweigh its disadvantages.

29. Intranet

30. What is Intranet ?
• Internal company network that uses Internet standards
(HTML, HTTP & TCP/IP protocols) & software.
• Accessed only by authorized persons, especially members or
employees of the organization

31. Intranet Security
Two levels of Security required:
• Internal
It can be imposed by Public Key Security & Encryption Key.
• External
Through Firewall.

32. What is Firewall ?
• Security device located between firm’s internal network
(intranet) & external network (internet).
• Regulates access into & out of a company’s network based on
a set of rules.
Note : needs to be upgraded from time to time to check latest potential
security problems.

33. Applications of Intranet
• Sharing of company policies/rules & regulations
• Access employee database
• Distribution of circulars/Office Orders
• Access product & customer data
• Sharing of information of common interest
• Launching of personal/departmental home pages
• Submission of reports
• Corporate telephone directories

34. Disadvantages
Management
problem Intranet on a routine basis
 Information overload lowers productivity
 True purpose of the Intranet is unknown to many
employees/departments
 Hidden or unknown complexity and costs
Productivity
problem
 Unauthorized access
 Abuse of access
 Denial of service
Security
problem
 A company may not have person to update their
 Fear of sharing information and the loss of control
 Limited bandwidth for the business

35. Extranet

36. What is Extranet ?
• Extranet is an Intranet for outside authorized users using
same internet technology.
• Inter-organizational information system.
• Enable outsiders to work together with company’s
employees.
• Open to selected suppliers, customers & other business
partners

37. Examples..
• Dealers/distributors have access to
product files such as :-
1. product specification,
2. pictures,
3. images, etc.
to answer the queries of the customer.

38. Benefits of Extranet
• Improved quality.
• lower travel costs.
• lower administrative & other overhead costs.
• reduction in paperwork.
• delivery of accurate information on time.
• improved customer service.
• better communication.
• overall improvement in business
effectiveness.

39. Disadvantages
• The suppliers & customer who don’t
have technical knowledge feel problem.
• Faceless contact.
• Information can be misused by other competitors.
• Fraud may be possible.
• Technical Employees are required.

40. Layered System View
Clients, partners, customers
Intranet
Extranet
Internet
Corporate members
Global society: competitors

41. THE END
Thank You