internet tech lessons
TRANSCRIPT
• 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.
Computer Networking
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.
Brief History of Networking
• 1961: Kleinrock - queuing theory showseffectiveness of packet-switching
• 1964: Baran - packet-switching in militaryapplications for survivable networks
• 1967: ARPAnet conceived by Advanced ResearchProjects Agency
History: Networking
• 1969: First ARPAnet node operational
–Prof.Kleinrock sends a message across fromUCLA to Stanford
• 1972:
–ARPAnet demonstrated publicly
–NCP (Network Control Protocol) first host-hostprotocol
–First e-mail program
–ARPAnet has 15 nodes
History: Networking
• Time sharing became difficult since different machineshad different operating systems, versions and programs–however, these led to development of Internet
• Vinton Cerf. Bob Kahn, Bob Braden and Jon Pesteldeveloped TCP/IP
• Cerf and Kahn’s internetworking principles:
– minimalism, autonomy - no internal changes requiredto interconnect networks
– best effort service model
– stateless routers
– decentralized control define today’s Internetarchitecture
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
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
History: Networking
• Early 1990’s: ARPAnet decommissioned
• Early 1990s: WWW
– Hypertext (1945 Bush: “As We May Think” article, TedNelson, Engelbert, Andries in 1968 )
– HTTP: Tim Berners-Lee develops WWW an Internet basedhypermedia initiative at CERN, specifies URLs, HTTP andHTML which became basis for today’s WWW
– 1994: Mosaic (Univ. of Illinois), later Netscape the majorbrowsers until late 1990’s
– late 1990’s: commercialization of the WWW, with introductionof HTTPS e-commerce is realized
Late 1990’s:
• est. 50 million computers on Internet
• est. 100 million+ users
• backbone links running at 1 Gbps
History: Networking
• 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.
What is Internet?
1960’sUS 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
1989Tim Berners-Lee proposes a new set of Internet
protocols
1995 US government releases Internet
for commercial use
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
o Do not copy copyrighted software
without the author’s permission.
o Always respect copyright laws and
policies.
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..
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
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 valuesare considered in the broadest sense so we musttake care while shaping content and services and weshould recognize that internet is not apart from universalsociety but it is a primary component of it.
Sensitivity to National and Local CulturesIt belongs to all and there is no barrier of national
and local cultures. It cannot be subject to one set ofvalues like the local TV channel or the localnewspaper We have to accommodate multiplicity ofusage.
While using e-Mail and chattingInternet must be used for communication with familyand friends. Avoid chatting with strangers andforwarding e-mails from unknown people /strangers. Andwe must teach children about risks involved in chattingand forwarding e-mails to strangers.
Pretending to be someone elseWe must not use internet to fool others by pretendingto be someone else. Hiding our own identity to foolothers in the Internet world is a crime and may also be arisk to others. It’s our responsibility to teachchildren the same.
Avoid Bad languageWe must not use rude or bad language while using e-mail, chatting, blogging and social networking, We needto respect their views and should not criticize anyoneon the internet and the same should be taught tochildren.
Hide personal informationWe should teach children not to give personal details
like home address, phone numbers, interests, passwords. Nophotographs should be sent to strangers and they should beasked to hide their personal details from strangers because itmight be misused and shared with others without theirknowledge.
While DownloadingInternet is used to listen and learn about music , It is also
used to watch videos and play games We must not use itto download them or share copyrighted material. The sameshould be taught to children, and they must be aware of theimportance of copyrights and issues of copyright.
SupervisionYou should know what children are doing on the
internet and the sites they visit on the internet andshould check with whom they are communicating.Restrict them browsing inappropriate sites. Parentalinvolvement is essential when a child is using theinternet in order to make him follow the rules.
Encourage children to use InternetWe must encourage children, students and
others to gain the knowledge from the internet and useit wisely. Internet is a great tool where we can gatherinformation which can be used for learning.
Access to InternetThe 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, understandand assess that information. Searching for information on theinternet can help to develop these skills.
Classroom exercises and take-home assessment tasks,where students are required to compare website content, areideal for alerting students to the requirements of writing fordifferent audiences, the purpose of particular content,identifying and judging accuracy and reliability.
Since many sites adopt particular views about issues, theinternet is a useful tool for developing the skills of distinguishingfact from opinion and exploring subjectivity and objectivity.
Internet, Intranet and
Extranets
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 ofprivate and public, academic, business, and governmentnetworks (local or Global),
linked by copper wires, wireless connections, and othertechnologies.
Hardware and Software of Internet
Variety of hardware and software are used to make
Internet functional.
• Modem
Device that enables computers to communicatethrough phone lines.
When we start internet the our modem communicatesto modem of ISP.
• Computer
In addition to a modem, you need a client capable ofhandling multiple data types.
• Software
Two types of software’s required to enable your PC as anInternet PC.
• Communication software to establish connection
• Client software for browsing, e-mail, news.
these software’s are provided with windows itself.
Continued…
Applications Of Internet
• Download programs and files
• Voice and Video Conferencing
• E-Commerce
• File Sharing
• Information browsing
• Search the web addresses for access through search engine
• Chatting and many more…
Disadvantages of Internet
• Theft of personal information such as name, address, credit cardnumber etc.
• Virus threats nothing but a program which disrupts the normalfunctioning of your system.
• Spamming refers to receiving unwanted e-mails in bulk, whichprovide no purpose and needlessly obstruct the entire system.
• Pornography This is perhaps the biggest threat related to children’shealthy mental life. A very serious issue concerning the Internet.
Though, internet can also create havoc, destruction andits misuse can be very fatal,the advantages of it outweigh its disadvantages.
Intranet
What is Intranet ?
• Internal company network that uses Internet standards(HTML, HTTP & TCP/IP protocols) & software.
• Accessed only by authorized persons, especially members oremployees of the organization
Intranet Security
Two levels of Security required:
• Internal
It can be imposed by Public Key Security & Encryption Key.
• External
Through Firewall.
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 ona set of rules.
Note : needs to be upgraded from time to time to check latest potentialsecurity problems.
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
Disadvantages
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
Management
problem Intranet on a routine basis
Extranet
What is Extranet ?
• Extranet is an Intranet for outside authorized users usingsame internet technology.
• Inter-organizational information system.
• Enable outsiders to work together with company’semployees.
• Open to selected suppliers, customers & other businesspartners
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.
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 businesseffectiveness.
Disadvantages
• The suppliers & customer who don’thave technical knowledge feel problem.
• Faceless contact.
• Information can be misused by other competitors.
• Fraud may be possible.
• Technical Employees are required.
Clients, partners, customers
Layered System View
Intranet
Extranet
Internet
Corporate members
Global society: competitors
THE END
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