INTRODUCTION TO COMPUTER NETWORK
1. Computer Network: The collection of interconnected computers is called a computer network.
2. LAN – Local Area Network: When the network of computer is confined to a small or localised
area, it is known as Local Area Network (LAN).
3. MAN – Metropolitan Area Network: A metropolitan area network is the network which is
spread over a city.
4. WAN – Wide Area Network: The network of computers which is spread across the countries
probably over the entire world is known as a Wide Area Network (WAN).
5. PAN – Personal Area Network: PAN refers to a computer network, which is used for
communication among computer devices spread over a few meters.
6. Switch: A switch is a network device which is used to interconnect computers or devices on a
network.
7. Repeater: A repeater is a device that is used to amplify and regenerate a signal which is on its
way through a communication channel.
8. Gateway: It connects different computer networks so that information can be passed between
them.
9. Router: A device that forwards data packets from one network to another by finding the
shortest route, based on an internal routing table
10. Nodes: It refers to the computers that are attached to a network and are seeking to share the
resources.
11. Server: A computer that facilitates the sharing of data, software and hardware resources on the
network is called server.
12. Modem: A modem (modulator/demodulator) is a hardware device that allows a computer to
send and receive information over telephone lines.
13. Hub: A hub is an electronic device that connects several nodes to form a network and redirects
the received information to all the connected nodes in broadcast mode.
14. Bus Topology: Bus topology is a topology for a Local Area Network (LAN) in which all the nodes
are connected to a single cable.
15. Terminator: The starting and ending point of cable is called terminator.
16. Star Topology: A star topology is a topology where all the computers connect to the single
central computer using it as a hub.
17. Tree Topology: Tree topology is a topology which has a root node and all other nodes are
connected to it forming a hierarchy. It is also called hierarchical topology.
18. Mesh Topology: Mesh topology is a group of nodes which are all connected to each other and
many types of connections are possible in a mesh topology.
19. Internet: Internet is a massive network of networks which connects millions of computers
together globally, forming a network in which any computer can communicate with another
computer.
20. World Wide Web (WWW): World Wide Web is an information system that identifies all the web
resources by Uniform Resource Locator (URL).
21. Uniform Resource Locator (URL): A URL is the address of a given unique resource on the Web
that matches users to a specific resource online.
22. E-mail: E-mail is defined as the transmission of messages over communications networks.
23. Messages: Messages are notes entered from keyboard and sent over internet using computer or
mobile.
24. Chat: Chat refers to any kind of communication over the Internet that offers a real-time
transmission of text messages from sender to receiver.
25. VoIP: Voice over Internet Protocol (VoIP) is a technology that allows you to make voice calls
using a broadband Internet connection instead of a regular phone line.
26. Website: Website is a collection of web pages which are grouped and connected together in
various ways.
27. Webpage: A document which can be displayed in a web browser is called Webpage.
28. Web Server: Web server is a computer that stores web server software and a website's
component files.
29. Web Hosting: Web hosting is an online service that enables you to publish your website or web
application on the internet.
30. Web Brower: Web browser is an application used to access and view websites.
31. Plug-ins: A software component that adds a specific feature to an existing computer program is
called plug-ins.
32. Add-ons: Add-ons are hardware units that can be added to a computer to increase the
capabilities or a program unit that enhances primary program.
33. Cookies: Cookies are small files which are stored on a user’s computer and contains information
such as webpages visited in the past, log-in details, etc.
34. HTTP: The information over the web is shared using a protocol called Hyper Text Transfer
Protocol (HTTP).
35. Hyper Text Mark-up Language (HTML): It is a mark-up language that defines a web page and is
used to create HTML documents.
36. Static Webpages: Static web pages are simple HTML written pages which serve as response from
browser to server in which all the information and data is static in nature.
37. Dynamic Webpages: Dynamic webpages are the pages written in some complex language in
which data is rendered after some interpretation and capacity to produce distinctive content for
different calls.
SOCIETY, LAW AND ETHICS
1. Digital Footprint: A digital footprint is a body of data that you create while using the Internet.
2. Net Etiquette: Net Etiquette are the rules that have developed as people have begun to
communicate and interact on the Internet.
3. Communication Etiquette: It refers to the accepted codes of conduct with respect to
interpersonal communication.
4. Data Protection: Data protection refers to the practices, safeguards, and binding rules put in
place to protect your personal information and ensure that you remain in control of it.
5. Personal Data: Personal data is any information relating to you, whether it relates to your
private, professional or public life.
6. Intellectual Property Rights (IPR): It refers to the rights of the owner of information to decide
how much information is to be exchanged, shared or distributed.
7. Plagiarism: It refers to stealing someone else’s intellectual work and representing it as your own
work without citing the source of information.
8. Paraphrasing: The act of changing the words or sentence construction of a copied document is
called paraphrasing.
9. Accidental Plagiarism: It involves careless paraphrasing, quoting text excessively along with poor
documentation.
10. Deliberate Plagiarism: It includes copying someone else’s work or any kind of information from
electronic sources without the permission of the original author.
11. Digital Property: It refers to any information about you or created by you that exists in digital
form, either online or electronic storage device.
12. Free Software: It is a software that is freely accessible and can be freely used, changed,
improved, copied and distributed by all who wish to do so.
13. Open Source Software: It is a software that can be freely used but does not have to be free of
charge.
14. Free and Open Source Software (FOSS): It refers to the software which is free as well as open.
15. Privacy: It is the protection of personal information given online.
16. Online Fraud: It is the fraud committed using the internet.
17. Cyber Crime: It is any criminal offense that involves the use of electronic communications or
information systems.
18. Phishing: It is the practice of attempting to acquire sensitive information from individuals over
the Internet by means of deception.
19. Scams: Any fraudulent business practice that extracts money from an unsuspecting, ignorant
person is called scam.
20. Online Scams: Scams that are committed over the Internet are called online scams.
21. Copyright: It is a form of protection given to the authors of “original works of authorship”.
22. Software Copyright: It is used by software developers and proprietary software companies to
prevent the unauthorized copying of their software.
23. Cyber Law: It is a generic form which refers to all the legal and regulatory aspects of Internet
and the World Wide Web.
24. Hacking: Hacking is an unauthorised access to or control over computer network security
systems for some illicit purpose.
25. Cyber Bullying: Cyber bullying is the harassment or bullying executed through digital devices.
26. E-waste: E-waste broadly covers waste from all electronic and electrical appliances and
comprises of items such as computers, mobile phones, etc.
27. Identity Theft: It occurs when someone uses another person’s personal information to take on
that person’s identity in order to commit fraud or other crimes.
TYPES OF TOPOLOGIES – ADVANTAGES AND DISADVANTAGES:
1
Topology Name
Bus Topology
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2
Tree Topology
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3
Star Topology
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Advantages
Easy to install
Requires less cable length, i.e.,
cost effective
Failure of a node does not
affect the network
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Extension of bus and star
topology
Easy expansion of nodes
Easily managed and maintained
Easy error detection
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Easy to trouble shoot
Single node failure does not
affect the entire network
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Disadvantages
Entire network might break
due to terminator fault
Not suitable for large number
of computers
Only one node can transmit
data at a time
Heavily cabled
Costly
Difficult to maintain when
more nodes are added
Network fails when central
hub fails
Difficult to expand
Longer cable is required
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4
Mesh Topology
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Easy fault detection and
removal of faulty parts
Network is not affected when
workstation fails
Possible to transmit data from
one node to many nodes
Easy diagnosis of fault
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Expensive due to cost of hub
and longer cables
Entire network fails if hub
fails
Difficult to install and
configure
Cabling cost is more
Bulk wiring is required
IT (AMENDMENT) ACT, 2008:
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In India, the cyber laws are enforced through Information Technology Act, 2000, which was
notified on 17 October 2000.
Its prime purpose was to provide legal recognition to electronic commerce and to facilitate filing
of electronic records with the Government.
The act was later amended in December 2008 through the IT (Amendment) Act, 2008.
It provided additional focus on Information Security.
The Information Technology Amendment Act, 2008 came into force from October 27, 2009
onwards.
E-WASTE DISPOSAL PROCESS:
A. Dismantling:
 Removal of parts containing dangerous substances
 Removal of easily accessible parts containing valuable substances
B. Segregation:
 This separation is done in a shredder process
C. Refurbishment and Reuse:
 It has potential for those used electrical and electronic equipments which can be easily
refurbished to put to its original use
D. Recycling:
 Ferrous metals in electrical
 Non-ferrous metals in smelting plants
 Precious metals in separating works
E. Treatment of Dangerous Waste:
 Shredder light fraction is disposed off in landfill sites or incinerated
 Chlorofluoro-carbons are treated thermally
 Printed Circuit Board is incinerated or disposed off in underground storages
 Mercury is recycled or disposed off in underground landfill sites