This document discusses computer networks and networking concepts. It defines a computer network and describes the main objectives of sharing information and resources. It discusses different types of networks like LAN, WAN, MAN and wireless networks. It also covers various networking terminologies like bandwidth, protocols, multiplexing, and network devices like hubs, switches, routers and gateways. Finally, it discusses different data transmission media and modes used in computer networks.

1. Computer NetworkComputer Network
ByBy
Dr. Pravin H. GhosekarDr. Pravin H. Ghosekar
M.Sc.(C/S), MCM, DBM, M.Phil(IT), M.Phil(Comm), MBA, BJ. Ph.D.M.Sc.(C/S), MCM, DBM, M.Phil(IT), M.Phil(Comm), MBA, BJ. Ph.D.
HOD Computer DepartmentHOD Computer Department
Dhanwate National CollegeDhanwate National College
NagpurNagpur
08/10/201008/10/2010

2. Network
• Computer networks is an interconnected collection of
autonomous computers.
• These computers are said to be interconnected if
they are able to exchange information
• A computer network is a network of computers that
are geographically distributed, but connected in such
a way that which enable meaningful transmission and
exchange of data among them.
• Sharing of information, resources (both hardware &
software including printer, fax, files, folders, etc.),
and processing load is main objective of computer
network.

3. Applications Network
• File Sharing
• Printer Sharing
• Communication & Collaboration
• Organisation
• Remote Access
• Data Protection
• Distributed Processing

4. Forms of Data Communication
• Analog eg. Telephone produce analog signals
• Digital eg. Computers produce digital signals
(0s and 1s)

5. Data Transmission Modes
• Transmission on a communications channel between two
machines is performed in three different modes. viz.
Simplex, Half-Duplex, Full Duplex.
• Transmission mode determine the number of bits sent over
the medium simultaneously

6. Types of Network
• LAN (Local Area Network) upto 2 km
• WAN (Wide Area Network) more than 100 km
• MAN (Metropolitan Area Network) upto 100 km

7. Network Topology
• Each computer or device in a network is
called a node.
• The geometrical arrangement of computer
resources, remote device, and communication
facilities is known as network topology

8. Data Transmission Media/Channels
• Data Communication Media (channels) are a
medium through which data travels between
from sender to receiver.
• Transmission are of different types as
follows :
• Twisted pair
• Co-axial

9. Data Transmission Media/Channels
• Fibre Optic
• Microwave
• Satellite communication

10. Wireless Network
• Wireless networks are different types of computer network
that are wireless.
• Wireless telecommunications networks are generally
implemented using electromagnetic waves, such as radio
waves, microwave, short waves, etc
• Wireless network can be divided into three categories
• Wireless PAN :(interconnects devices within a relatively
small area)
• Wireless LAN :
• Wi-Fi: Wireless Fidelity
• Fixed Wireless Data:
• Wireless MAN : Wi-Max (Worldwide Interoperability
for Microwave Access )

11. Network Terminologies
• Bandwidth : the amount of data that can be
carried from one point to another in a given
time period (usually a second) which is
measured in bits (of data) per second (bps)
• Protocol : It is a set of rules and procedures
that govern transmission between the
components in a network
These rules provide a method for orderly
and efficient exchange of data between
sender and receiver

12. Network Terminologies
• Protocols :
• TCP/IP (Transmission Control Protocol /
Internet Protocol): TCP/IP is a protocol suite,
which consists of protocols for all 4 layers. It is
used for Intranet and Internet. The protocol
ensures error-free transmission.
• HTTP (HyperText Transmission Protocol) : is a
networking protocol for distributed,
collaborative, hypermedia information systems.

13. Network Terminologies
• Protocols :
• POP3 (Post Office Protocol) : It is used for E-
mail client to retrieve E-mail from server
• SMTP (Simple Mail Transfer Protocol) : used
for transmission of E-mail across Internet
• FTP (File Transfer Protocol) : It enables a host
to send and receive files over the network –
internet as well as intranet.
• DNS (Domain Name Service Protocol) :
Translates server address to IP address.

14. Network Terminologies
• Modem : Modem stands for Modulator –
Demodulator. Modulator converts Digital signals
generated by computer into analog signals.
Demodulator converts an analog signal into a
digital signal. The goal is to produce a signal
that can be transmitted easily and decoded to
reproduce the original digital data.

15. Network Terminologies
• Multiplexer : It is the process of combining
signals from multiple sources for transmission
across a single data link.
• Multiplexing a voice telephone call means that
two or more separate conversations are sent
simultaneously over one communication circuit
between two different cities..
• Types :
• Frequency Division Multiplexing (FDM)
• Time Division Multiplexing (TDM)

16. Network Terminologies
• Telnet : The telnet application enables a use on
one computer to log on to another computer on
the network.
• Baud rate : The maximum number of signal
pulses that a communication line can handle per
second. Higher baud rates indicate greater
transmission capacities.
• Bridge : An internetworking device that
connects two similar networks.

17. Network Terminologies
• BPS : Bits per second. A unit of measurement
for data transfer rates.
• Client : A network node that uses services
provided by a server
• Server: Which provides services to clients
• Data compression : A procedure that uses
mathematical techniques to encode data so that
it uses less space.
• Data encryption : A security procedure that
encodes data so that it cannot easily be
understood.

18. Network Terminologies
• Ethernet : A popular local area network that
uses a contention media-access method over a
bus topology of coaxial cable.
• Gateway : A computer that interconnects
different types of networks, translating
protocols as necessary. For example, a gateway
might connect personal computers on a LAN to
a mainframe computer
• Host : Computer that controls network
communication in a hierarchical network
• Hub :
• Switch :

19. Network Terminologies
• IEEE : Institute of Electrical and Electronics
Engineers. A standards organization
• OSI Open Systems Interconnection. : A proto-
type for network communication that promotes
interconnectivity.
• Peer-to-peer : Communication between two
network devices that have the same status on
the network
• Router A device that connects networks and
can determine the best path for data when
there are multiple paths

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