1. NETWORKING

2. DEFINATION
 A NETWORK IS A COLLECTION OF COMPUTER AND
DEVICES CONNECTED TO EACH OTHER AND SHARE
RESOURCES AND INFORMATION. THE ADVANCED
RESEARCH PROJECTS AGENCY (ARPA) DESIGNED
“ADVANCED RESEARCH PROJECTS AGENCY
NETWORK” (ARPANET) FOR THE UNITED STATES
DEPARTMENT OF DEFENCE. IT WAS THE FIRST
COMPUTER NETWORK IN THE WORLD IN LATE 1960’s
AND EARLY 1970’s.

3. NEED FOR NETWORKING
 SPEEDING THE WORK
 NO NEED TO PHYSICALCOLLECTION OF DATA
 ONE BRANCH OF ORGANIZATION CAN ACCESS DATA
FROM OTHER BRANCH WHICH IS SPREAD ACROSS
LARGE GEOGRAPHICAL AREA.
 MODERN AGE OF COMMUNICATION E.G. SENDING AND
RECEIVING E-MAILS.
 ONLINE CHAT SERVICES AND VIDEO CONFERENCING.

4. APPLICATIONS OF
NETWORKING
 Resource Sharing
 Hardware (computing resources, disks,
printers)
 Software (application software)
 Information Sharing
 Easy accessibility from anywhere (files,
databases)
 Search Capability (WWW)
 Communication
 Email
 Message broadcast
 Remote computing

5. BASIC EQUIPMENT –
NETWORK CARD
 A network interface
controller (also known
as a network interface
card, network
adapter, LAN adapter
and by similar terms)
is a computer
hardware component
that connects a
computer to a
computer network.

6. BASIC EQUIPMENT - CABLE
 Networking Cables
are used to connect
one network device to
other or to connect
two or more
computers to share
printer, scanner etc.
Different types of
network cables like
Coaxial cable, Optical
fiber cable, Twisted
Pair cables are used
depending on the
network's topology,
protocol and size.
Crimping Tool

7. BASIC EQUIPMENT – SWITCH
/ HUB
 A network switch is
a small hardware
device that joins
multiple computers
together within one
network.

8. BASIC EQUIPMENT –
ROUTER
 A router is
specialized
computer
connected to more
than one network.
A router runs
software that
allows the device
to move data from
one network to
another.

9. TYPES OF CABLES –
TWISTED PAIR
 Twisted pair cabling is a
type of wiring in which
two conductors (the
forward and return
conductors of a single
circuit) are twisted
together for the
purposes of canceling
out electromagnetic
interference (EMI) from
external sources; for
instance,
electromagnetic
radiation from
unshielded twisted pair
(UTP) cables, and
crosstalk between
neighboring pairs. It was
invented by Alexander

10. TYPES OF CABLES –
COAXIAL
 Coaxial cable, or coax,
is an electrical cable with
an inner conductor
surrounded by a flexible,
tubular insulating layer,
surrounded by a tubular
conducting shield. The
term coaxial comes from
the inner conductor and
the outer shield sharing
the same geometric
axis. Coaxial cable was
invented by English
engineer and
mathematician Oliver
Heaviside, who patented
the design in 1880

11. TYPES OF CABLES – FIBRE
OPTICS
 An optical fiber cable
is a cable containing
one or more optical
fibers. The optical
fiber elements are
typically individually
coated with plastic
layers and contained
in a protective tube
suitable for the
environment where
the cable will be
deployed.

12. MICROWAVES
 Microwave is a form of wireless technology which
is used to transfer digital information between two
computers that are at a distance of 10-12
kilometers.
 A microwave device has to be installed if a person
wants to communicate using microwave.
 A microwave always contains a digital modem,
radio frequency & antenna.
 If a microwave has a line of sight then only it can
work effectively.

13. TYPES OF NETWORKS – LAN
 A LAN is a Local Area Network. Local is generally
referred to a network contained within the
building or an office or a campus.
 To set up a LAN – relatively speaking – is cheap.

14. TYPES OF NETWORKS – WAN
 WAN (Wide Area Network)
 These networks are long distance networks
spread over different countries, states, cities etc.
 WAN services are provided by certain companies
like AT & T.
 The computers are connected to each other via
satellites or telephone lines
USA
WAN
Student Computer
Centre

15. TYPES OF NETWORKS – MAN
 MAN (Metropolitan Area Network)
 MAN covers different locations of a town or a city.
It is not limited to a geographical area as in LAN.
 Cable Television Network is one of the example
of MAN.

16. TYPES OF NETWORKS – HAN
 HAN (Home Area Network)
 This network is in an individual home that
connects a persons Digital devices from
computers and other devices such as printers to
telephones, DVD and other digital devices are
wired into network.

17. TYPES OF NETWORKS – CAN
 CAM (Campus Area Network)
 It is a network which link different campus offices
together.

18. NETWORK STRUCTURE –
PEER TO PEER
 In peer – to – peer network all the computer
connected to each other in a network.
 There is no server on this computer.
 The security is very less in this network.
 The network shares software / hardware / data
between all the computers

19. CLIENT / SERVER
NETWORKS
 Servers are used to perform certain specific task
such as database management, communication,
etc.
 The server distributes database files and
programs to the computers (client) on the
network.
 A client can be any computer on network. For
e.g. when a file is downloaded from a particular
server the client sends request to the server to
download the particular file.

20. NETWORK TOPOLOGIES -
BUS
 In this network all the computers are connected to each other
through bus.
 In this network number of computers are connected to each
other on a single coaxial cable.
 A Bus topology is normally advisable for limited number of
computers on the network.
 The computers are connected to each other on a single coaxial
cable there is no hub used in the network. The only
disadvantage is that failure in cable will cause complete network
failure.

21. NETWORK TOPOLOGIES -
RING
 In Ring network all the computers are connected to each
other in a ring shape.
 The computers are connected using Fiber Optics cable.
 The messages are transferred from one device/computer to
another only in one direction.
 A disadvantage of a token ring is if one computer is broken or
down, the message cannot be passed to the other computers.

22. NETWORK TOPOLOGIES -
STAR
 It has a central concentrator (hubs, switches) all the other
network devices / computers are connected to each other
through central concentration.
 This network is mostly used because failure in a single
system does not fail the network but the failure in central
concentrator causes the entire network breakdown.
 This network is costlier than other networks.

23. NETWORK MEDIA
(WIRELESS)
 Radio Network – is a network system which
distributes programming to multiple stations
simultaneously or slightly delayed for the
purpose of extending total coverage beyond
limits of a single broadcast signal.
 Infrared – data transmission is also a short
range communication among computer
peripherals and personal digital assistants.
These devices are usually conforms to
standards by IrDA – Infrared Data
Association e.g. Remote controls used
infrared LED’s (Light Emitting Diodes).

24. WHAT IS AN INTRANET?
An intranet is a computer network that uses Internet Protocol technology
to securely share any part of an organization's information or network
operating system within that organization. The term is used in contrast
to internet, a network between organizations, and instead refers to a
network within an organization. Sometimes the term refers only to the
organization's internal website, but may be a more extensive part of the
organization's information technology infrastructure. It may host multiple
private websites and constitute an important component and focal point
of internal communication and collaboration. Any of the well known
Internet protocols may be found in an intranet, such as HTTP (web
services), SMTP (e-mail), and FTP (file transfer protocol). Internet
technologies are often deployed to provide modern interfaces to legacy
information systems hosting corporate data.
An intranet can be understood as a private analog of the Internet, or as
a private extension of the Internet confined to an organization. The first
intranet websites and home pages began to appear in organizations in
1996-1997. Although not officially noted, the term intranet first became
common-place among early adopters, such as universities and
technology corporations, in 1992

25. INTRANET BENEFITS
 Workforce productivity: Intranets can help users to locate and view
information faster and use applications relevant to their roles and
responsibilities.
 Time: Intranets allow organizations to distribute information to
employees on an as-needed basis.
 Communication: Intranets can serve as powerful tools for
communication within an organization, vertically and horizontally
 Business operations and management: Intranets are also being
used as a platform for developing and deploying applications to
support business operations and decisions across the
internetworked enterprise
 Built for one audience: Many companies dictate computer
specifications which, in turn, may allow Intranet developers to write
applications that only have to work on one browser (no cross-
browser compatibility issues).
 Immediate updates: When dealing with the public in any capacity,
laws, specifications, and parameters can change. Intranets make it
possible to provide your audience with "live" changes so they are

26. EXTRANET
 An extranet is a computer network that allows
controlled access from the outside, for specific
business or educational purposes. An extranet can
be viewed as an extension of a company's intranet
that is extended to users outside the company,
usually partners, vendors, and suppliers. It has
also been described as a "state of mind" in which
the Internet is perceived as a way to do business
with a selected set of other companies (business-
to-business, B2B), in isolation from all other
Internet users. In contrast, business-to-consumer
(B2C) models involve known servers of one or
more companies, communicating with previously
unknown consumer users

27. EXTRANET ADVANTAGES AND
DISADVANTAGES
 Advantages
◦ Exchange large volumes of data using Electronic Data
Interchange (EDI)
◦ Share product catalogs exclusively with trade partners
◦ Collaborate with other companies on joint development efforts
◦ Jointly develop and use training programs with other companies
◦ Provide or access services provided by one company to a group
of other companies, such as an online banking application
managed by one company on behalf of affiliated banks
 Disadvantages
◦ Extranets can be expensive to implement and maintain within an
organization (e.g., hardware, software, employee training costs),
if hosted internally rather than by an application service provider.
◦ Security of extranets can be a concern when hosting valuable or
proprietary information.

28. ETHERNET
 Ethernet is a family of computer networking technologies for
local area networks (LANs) commercially introduced in 1980.
Standardized in IEEE 802.3, Ethernet has largely replaced
competing wired LAN technologies.
 Systems communicating over Ethernet divide a stream of data
into individual packets called frames. Each frame contains
source and destination addresses and error-checking data so
that damaged data can be detected and re-transmitted.
 Ethernet was developed at Xerox PARC between 1973 and
1975. It was inspired by ALOHAnet, which Robert Metcalfe had
studied as part of his Ph.D. dissertation. In 1975, Xerox filed a
patent application listing Metcalfe, David Boggs, Chuck Thacker
and Butler Lampson as inventors. In 1976, after the system was
deployed at PARC, Metcalfe and Boggs published a seminal
paper. Metcalfe left Xerox in 1979 to form 3Com. He convinced
Digital Equipment Corporation (DEC), Intel, and Xerox to work
together to promote Ethernet as a standard.

29. INTRODUCTION TO TCP/IP
 The Internet Protocol Suite is the set of
communications protocols used for the Internet
and other similar networks. It is commonly also
known as TCP/IP named from two of the most
important protocols in it: the Transmission
Control Protocol (TCP) and the Internet
Protocol (IP), which were the first two
networking protocols defined in this standard.
Modern IP networking represents a synthesis
of several developments that began to evolve
in the 1960s and 1970s, namely the Internet
and local area networks, which emerged during
the 1980s, together with the advent of the

30. DATA COMMUNICATION

31. INTRODUCTION
 Today computer is available in many offices and
homes and therefore there is a need to share data
and programs among various computers. With the
advancement of data communication facilities the
communication between computers has increased
and thus it has extended the power of computer
beyond the computer room. Now a user sitting at
one place can communicate with computers of any
remote site through communication channel. The
aim of this lesson is to introduce you the various
aspects of computer network.

32. DATA COMMUNICATION
 We all are acquainted with some sorts of communication in our day
to day life. For communication of information and messages we use
telephone and postal communication systems. Similarly data and
information from one computer system can be transmitted to other
systems across geographical areas. Thus data transmission is the
movement of information using some standard methods. These
methods include electrical signals carried along a conductor, optical
signals along an optical fibers and electromagnetic areas.
 Suppose a manager has to write several letters to various clients.
First he has to use his PC and Word Processing package to prepare
the letter, if the PC is connected to all the client's PC through
networking, he can send the letters to all the clients within minutes.
Thus irrespective of geographical areas, if PCs are connected
through communication channel, the data and information, computer
files and any other programs can be transmitted to other computer
systems within seconds. The modern form of communication like e-
mail and Internet is possible only because of computer networking.

33. BASIC ELEMENTS OF A
COMMUNICATION SYSTEM
 The following are the basic requirements for working of a
communication system.
◦ The sender (source) who creates the message to be
transmitted
◦ A medium that carries the message
◦ The receiver (sink) who receives the message
 In data communication four basic terms are frequently used.
They are:
◦ Data : A collection of facts in raw forms that become
information after processing.
◦ Signals : Electric or electromagnetic encoding of data.
◦ Signaling : Propagation of signals across a communication
medium.
◦ Transmission : Communication of data achieved by the

34. COMMUNICATION
PROTOCOL
 You may be wondering how computers send and receive data across
communication links. The answer is data communication software. It is this
software that enables us to communicate with other systems. The data
communication software instructs computer systems and devices as to how
exactly data is to be transferred from one place to another. The procedure of
data transformation in the form of software is commonly known as protocol.
 The data transmission software or protocols perform the following functions
for the efficient and error free transmission of data.
 Data sequencing : A long message to be transmitted is broken into smaller
packets of fixed size for error free data transmission.
 Data Routing : It is the process of finding the most efficient route between
source and destination before sending the data.
 Flow control : All machines are not equally efficient in terms of speed.
Hence the flow control regulates the process of sending data between fast
sender and slow receiver.
 Error Control : Error detecting and recovering is the one of the main
functions of communication software. It ensures that data are transmitted
without any error.

35. DATA TRANSMISSION MODES
 There are three ways for transmitting data from one point to
another

 Simplex : In simplex mode the communication can take place
in one direction. The receiver receives the signal from the
transmitting device. In this mode the flow of information is
Uni-directional. Hence it is rarely used for data
communication.

 Half-duplex : In half-duplex mode the communication
channel is used in both directions, but only in one direction at
a time. Thus a half-duplex line can alternately send and
receive data.

 3. Full-duplex : In full duplex the communication channel is
used in both directions at the same time. Use of full-duplex
line improves the efficiency as the line turnaround time
required in half-duplex arrangement is eliminated. Example of
this mode of transmission is the telephone line.

36. TYPES OF COMMUNICATION
SERVICES
 A term used to describe the data-handling capacity of a communication service is
bandwidth. Bandwidth is the range of frequencies that is available for the transmission of
data. A narrow range of frequencies in a communication system is analogous to a
garden hose with a small diameter. The flow of information in such a system its data rate
is restricted, just as is the flow of water in the narrow hose. Wider bandwidths permit
more rapid information flow. The communication data transfer rate is measured in a unit
called baud. Baud is identical to bits per second. Therefore, a rate of 300 baud is 300
bits per second.
 Communication companies such as American Telephone and Telegraph (AT&T) and
Western Union are called common carriers, and they provide three general classes of
service for both voice and data communication:
 Narrowband handles low data volumes. Data transmission rates are from 45 to 300
baud. The low-speed devices might use narrow band communications.
 Voiceband handles moderate data transmission volumes between 300 and 9600 baud.
They are used for applications ranging from operating a CRT to running a line printer.
Their major application is for telephone voice communication hence, the term voiceband.
 Broadband handles very large volumes of data. These systems provide data
transmission rates of 1 million baud or more. High-speed data analysis and satellite
communications are examples of broadband communication systems.

37. MODEM
 A modem (modulator-demodulator) is a device that modulates
an analog carrier signal to encode digital information, and
also demodulates such a carrier signal to decode the
transmitted information. The goal is to produce a signal that
can be transmitted easily and decoded to reproduce the
original digital data. Modems can be used over any means of
transmitting analog signals, from light emitting diodes to
radio. The most familiar example is a voice band modem that
turns the digital data of a personal computer into modulated
electrical signals in the voice frequency range of a telephone
channel. These signals can be transmitted over telephone
lines and demodulated by another modem at the receiver
side to recover the digital data.
FAX MODEM
 A fax modem enables a computer to transmit and receive
documents as faxes. A fax modem is like a data modem but is
designed to transmit and receive documents to and from a fax
machine or another fax modem. Some, but not all, fax
modems do double duty as data modems. As with other
modems, fax modems can be internal or external. Internal fax
modems are often called fax boards.

38. WIRELESS NETWORK
 Wireless network refers to any type of computer network that is not
connected by cables of any kind. It is a method by which telecommunications
networks and enterprise (business), installations avoid the costly process of
introducing cables into a building, or as a connection between various
equipment locations. Wireless telecommunications networks are generally
implemented and administered using a transmission system called radio
waves. This implementation takes place at the physical level (layer) of the
network structure.
WIFI
 Wi-Fi is a mechanism for wirelessly connecting electronic devices. A device
enabled with Wi-Fi, such as a personal computer, video game console,
smartphone, or digital audio player, can connect to the Internet via a wireless
network access point. An access point (or hotspot) has a range of about 20
meters (65 ft) indoors and a greater range outdoors. Multiple overlapping
access points can cover large areas.
 "Wi-Fi" is a trademark of the Wi-Fi Alliance and the brand name for products
using the IEEE 802.11 family of standards. Wi-Fi is used by over 700 million
people. There are over four million hotspots (places with Wi-Fi Internet
connectivity) around the world, and about 800 million new Wi-Fi devices are
sold every year.[citation needed] Wi-Fi products that complete Wi-Fi Alliance
interoperability certification testing successfully may use the "Wi-Fi
CERTIFIED" designation and trademark.

39. WAP
 Wireless Application Protocol (WAP) is a
technical standard for accessing information
over a mobile wireless network. A WAP
browser is a web browser for mobile devices
such as mobile phones (called "cellular
phones" in some countries) that uses the
protocol.
 Before the introduction of WAP, mobile
service providers had limited opportunities to
offer interactive data services, but needed
interactivity to support Internet and Web
applications such as:
◦ Email by mobile phone
◦ Tracking of stock-market prices
◦ Sports results
◦ News headlines
◦ Music downloads

40. WAP
 Wireless Access Point(WAP) is required
for accessing wireless LAN (Local Area
Network). Multiple computers can be
connected through a single WAP. It
connects to Ethernet locate Area
Network and allow computers connected
on wireless to function in Ethernet LAN
environment.