Networking and telecommunication

By Roshan Maharjan
For Class 10

1. NETWORKING AND TELECOMMUNICATION
By : RoshanMaharajan
Networking and Telecommunication 1

2. Communication
■Sending and receiving information between two or more persons is called
communication.
■Communication is giving, receiving or exchanging ideas, information, signals or
messages through appropriate media
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3. Telecommunication
■A system of transmission of text, image, data and sound in the form of electronic
signalsis known as telecommunication.
■Telecommunication isthe transmission of information by various types of
technologies over wire, radio, optical or other electromagnetic systems.
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4. Data communication
■Data communication system is the collection ofhardware, software and other
devices that allows exchanging data, information and voice between two or more
device through a wire or radio wave.
■For examples: E-mail, Chat etc.
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5. Components of Data communication
❑Message:Itistheinformationtobedelivered.
❑Sender:Senderisthepersonwhoissendingthemessage.
❑Receiver:Receiveristhepersontowhomthemessageisbeingsentto.
❑Medium:Itisthemediumthroughwhichthemessageissent.For
example:AModem.
❑Protocol:Thesearesomesetofruleswhichgoverndatacommunication.
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6. Protocol
•A set of rules that must be
followed by sender and
receiver to make
communication possible is
known as protocol.
Medium
•A path through which the
sender makes
communication to the
receiver is known as
medium.
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7. Modes of Data Transmission
a) Simplex mode :
■Simplex mode communication is a mode of communication or data transmission in
which data flows in one direction only.
■The communication is unidirectional.
■E.g.: Newspaper and television broadcast.
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8. Continue…..
b) Half duplex mode :
■Half duplex communication is a mode of transmission in which data can be
transmitted in both directions but only in one direction at a time.
■It is also referred to as Semi-Duplex.In other words, each station can both transmit
and receive the data but not at the same time. When one device is sending the
other can only receive and vice-versa.
■E.g.: Wireless handset and walky-talky.
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9. Continue…..
c) Full Duplex Mode:
■Full duplex communication is a mode of transmission in which data is transmitted in
both the direction simultaneously on the same channel.
■It is bi-directional in nature.
■It is two-way communication in which both the stations can transmit and receive the
data simultaneously.
■E.g.: Telephone, internet chat, etc.
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10. Bandwidth
■Bandwidth can be defined as the data handling capacity of a communication
system. It is measured in cycles per second (cps) and bits per second (bps) in
analogue and digital devices respectively.
■The maximum volume of data that can be transmitted through communication
is called bandwidth.
■We can measure bandwidth in digital devices by bits per secondand in
analogue devices by cycles per second or Hertz (Hz).
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11. Communication or Transmission
Medium
■Communicationortransmissionmediumisachannelthroughwhich
dataorsignalscanbetransmittedfromonepointtoanother.
■Transmissionmediaisacommunicationchannelmeansitisa
mediumfordatatransmission.Inotherwords,whentwodeviceswant
tocommunicate,atthattimethecommunicationchanneltheyusedis
calledtransmissionmedia.
■TransmissionMediumisusedtocarrydatafromthetransmittertothe
receiver.
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12. Types of communication Medium
■Guidedorboundedorwiredmedium
•Itisthetransmissionmediuminwhichdatasignalsflowthroughspecifiedpathincableor
wires.
•Asignaltravelingalonganyofthesemediaisdirectedandcontainedbythephysicallimitsof
themedium.
➢E.g.:Twistedpaircable,Co-axialcable,Fiberopticscable,etc.
■Unguidedmediumorunboundedorwireless
•Itisthetransmissionmediuminwhichdata/signalsflowthroughtheair.
•Unguidedmediumtransportelectromagneticwaveswithoutusingaphysicalconductor.
•Signalsarenormallybroadcastthroughfreespaceandthusareavailabletoanyonewhohas
adevicecapableofreceivingthem.
➢E.g.:radiofrequency,microwave,infraredtransmission,etc.
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13. Guided Transmission Media
Twisted pair cable
■The type of wires which are made of copper and a pair of wires are twisted
together is known as twisted pair cable.
■RJ –45 is the connector used.
■A twisted pair cable comprises of two separate insulated copper wires,
which are twisted together and run in parallel. The copper wires are typically
1mm in diameter. One of the wires is used to transmit data and the other is
the ground reference.
■Example: Ethernet cable, telephone
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14. Continue…..
Co-axial cable
■A wire with single ended single reference where the central conductor
carries the data signal.
■Coax has a central core of stiff copper conductor for transmitting
signals. This is covered by an insulating material. The insulator is
encased by a closely woven braided metal outer conductor that acts as
a shield against noise. The outer conductor is again enclosed by a
plastic insulating cover.
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15. Continue….
Fiber optics cable
■Fiber optics cable is one of the costlier cables used in data communication which uses
light to carry a data signal through the cable.
■ST and SC are the connectors used in this cables.
■A fiber optic cable is anetwork cable that contains strands of glass fibers inside an
insulated casing.
■They're designed for long-distance, high-performance data networking, and
telecommunications.
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16. Unguided Transmission Media
Radio wave transmission
■A type of unguided transmission in which the signal is carried over by carrier wave is known
as radio wave transmission.
Microwave transmission
■Microwave, which is also called line of sight communication, is a wireless technology that can
be used to transmit data between two different networks or computers.
■They are electromagnetic waves with a wavelength longer than infrared light and shorter than
radio wave.
Infrared transmission
■Infrared transmissions are just below visible transmission light which allows high speed data
transmission.
■It is optical in nature, carried by beams of light invisible to naked eye.
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17. Differentiate between Guided and Unguided media
Guidedmedia Unguided media
It is the transmission media in which data signals
flows through specified path.
It is the transmission media in which data signal
flows through air.
Data or a signal sent through it propagates in the
form of voltage, current or photons.
Data or a signal sent through it propagates in the
form of electromagnetic waves.
It is mainly suited for point to point line
configuration.
It is mainly used for broadcasting purposes.
Example: twisted pair cable, co-axial cable, fiber
optics, etc.
Example: radio wave, microwave, infrared, etc
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18. Differentiate between shielded and unshielded
twisted pair.
Shielded twisted Pair Unshielded twisted pair
It is made up of twisted pair wires with additional
shielded and drain wires.
It is made up of twisted pair wires without
additional shielded and drain wires.
D-shell connectors are used with shielded twisted
pair.
RJ-45 connector is commonly used with
unshielded twisted pair.
It is costlier than UTP cables. It is cheaper than STP cables.
It has got better noise rejection capacity. It has poor noise rejection capacity.
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19. Differentiate between radio wave and microwave
communication media.
Radio communication media Microwave communication media
It is a form of wireless communications in which
signals are sent through radio frequency waves.
It is a form of wireless communication in which
data signals are sent through pulses of
electromagnetic energy.
It requires antenna for connection. It requires repeater or amplifier for
communication.
It provides low bandwidth for data communication.It provides higher bandwidth for data
communication.
It doesn’t require a line of sight. It requires a line of sight.
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20. Computer network
■Computer network means two or more computers connected with each other to
share data, hardware, software and other resources.
■The interconnection of computer through transmission media in order to
communicate and share resources.
■Networks are usually used to share resources, exchange files or communicate with
other users.
■A network is a set of nodes connected by communication links.
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21. Advantages and disadvantages of
computer network
Advantages
i) Computer in a network can access
network connected hardware devices
like printer, disk drives, etc.
ii) Information can be exchanged
rapidly in computer network.
iii) Computers in a network environment
can be updated from any computer.
iv) Software packages can be shared
between network connected
computers.
Disadvantages
i) Failure of server stops application
being available.
ii) Network failure causes loss of data.
iii) Network makes user works
dependent.
iv) System opens to hackers.
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22. Hardware components
Physical parts and devices used to connect computers in the network
environment are called hardware components.
■Computer System
Server
A server is the main computer that provides services, data and other resources to the
other computers in the network environment.
❖File server Database server
❖Printer server Network server
❖Modem server
Workstation
▪Network Interface Unit
▪Communication Channel or Transmission media
▪Network Devices
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23. Types of Networks
■On the basis of coverage area, there are three types of computer network.
a.Local Area Network (LAN)
b.Metropolitan Area Network (MAN)
c.Wide Area Network (WAN)
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24. Local Area Network (LAN)
■A LAN is a network of computers that are relatively near to each other and are
connected in a way that enables them to communicate by using cables and small
wireless devices.
■LAN are usually connected with cables (Coaxial cable or twisted pair cable).
■Wireless media are also used for connecting computers on the LAN which is known
as WLAN (Wireless Local Area Network)
Features of LAN
i) The diameter is not more than a few km.
ii) LAN offers high bandwidth of 10-100 Mbps.
iii) It is controlled by single organization.
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25. Metropolitan AreaNetwork(MAN)
■A MAN is a network of computer is computers which are spread over a metropolitan
area such as within a city.
■It is Mid range network i.e. larger than LAN and smaller than WAN.
■In MAN, cables (especially fiber optic cable) and unbounded Communication media
( microwave transmission, radio wave, etc) are used as transmission channels.
Features of MAN
i) It covers a limited geographical area.
ii) It may be owned by single or multiple organizations.
iii) It uses cable or wireless connections.
iv) It uses private or public connection medium.
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26. Wide Area Network (WAN)
■A WAN is a network system of connecting two or more computers generally across a
wide geographical area such as cities, districts, and countries.
■A WAN contains many groups of LANs and MANs.
■It uses telephone line, microwave, radio wave or satellite links to connect.
■The internet is the largest WAN.
Features of WAN
i) It covers a large geographical area.
ii) It is owned by multiple organizations.
iii) It uses public connection medium.
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27. Network Topology(LAN Topology)
■The topology is a term used to describe the way In which the end points or nodes of
a network are linked together.
■It describes the manner in which nodes and network devices on the network are
connected with cables and how they communicate.
■The physical layout of cabling for connecting computers and other network devices
on the LAN is known as Network Topology.
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28. Bus topology
■The topology in which computers and other devices are arranged in linear format is called
bus topology/ linear topology.
■Coaxial cables of different length are used.
■Both ends of each segment of coaxial cable BNC(Bayonet Neill–Concelman) are connected
and further connected with T –connectors.
■Terminators are attached at both the ends of the network bus.
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31. Ring topology
■The topology in which computers are connected in a closed loop or a circle /
ring without any end points is called ring topology.
■Signals are transmitted in one direction i.e. clockwise or counterclockwise.
■Generally coaxial cables are used along with BNC connector and T-
connector.
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33. Star topology
■The topology in which all computers or the network devices are connected through a
central device in the shape of star structure is called star topology.
■Twisted pair cables(especially UTP cables) are used.
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35. Mesh topology
■A mesh topology is anetwork setup where each computer and network device is
interconnected with one another.
■This topology setup allows for most transmissions to be distributed even if one of
the connections goes down.
■It is a topology commonly used for wireless networks.
■Each node is connected with more than one node separately.
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36. Client/Server network
■Client/ server network is a type of network architecture that consist of at least one server and one or more
workstations.
■It is also known as Domain Model.
■Server computer controls and manages clients and provides resources to the client when requested.
■Server is also called back-end and client is front-end.
Advantages
■It is more secured
■Network administration work is easier.
■Network can be expanded easily.
■Required application software cab be installed on the server computer
Disadvantages
■It is more expensive than peer-to-peer and difficult to set up.
■A well-trained network administration is required to manage network.
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37. Client/Server network
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38. Peer-to-peer network (P2P)
■A Peer-to-peer network is a type of network architecture in which computers function both as
workstation and server.
■It is also known as Workgroup Model.
■Each computer has equal right as each computer is server itself.
Advantages
■It simple and easy to manage.
■It is easier to setup.
■Each computer can determine resources to be shared .
Disadvantages
■The expansion of network is limited.
■It tends to slow down with network load.
■It has low level security.
.
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39. Centralized computing network
■A centralized computing network is a network in which a central host computer performs data
processing and storage on behalf of clients.
Workstation
■Workstation is a computer network that utilizes network resources.
■It is also known as client computer.
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40. Differentiate between client/server network and
peer-to-peer network.
client/server network Peer-to-peer network.
It consists of at least one server and one or more
client.
It is a group of computers which function both
as server and workstation.
It provides centralized network administration. It lacks centralized network administration
It provides high security of data and other
resources.
It provides no reliable security and might put data
on risk.
It is suitable for large organization where data
security is required
It is suitable for small organization and home
usage where data and other securities are not
required.
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41. Network Devices
Router
■A router is an intelligent network device which connects two different networks having same
protocol.
■It keeps data flowing between networks and keeps the networks connected through the most
efficient available route.
■When router receives data packets, it checks the network address i.e. IP address of the data
packets and determines whether the data packets need to forward to other network or not.
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42. Hub
■A hub is a network device that joins multiple computers and other devices
through its port.
■A hub looks like a small rectangular box which has a series of connecting
ports.
■When a hub receives a packet of data at one of its port from a PC on a
network, it transmits the packets to all the ports.
■It is also referred as multi-port repeater.
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43. Switch
■A switch is a network device that connects computers, network devices and LAN
segments.
■Aswitch, in the context ofnetworking, is a high-speed device that receives
incoming data packets and redirects them to their destination on a local area
network (LAN).
■It can support all types of packet protocols.
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44. Bridge
■A Bridge is a device that joins the segments of a similar (having same topology)
or dissimilar network(having different topology) to transfer data and
information using the same protocol
■When any node on a segment sends data or message, it checks the source
and the destination of each packet and if the destination node is in the same
segment it does not forward the packet to other segment.
■The bridges are intelligent devices that allow the passing of only selective packets
from them.
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45. Gateway
■Gateway is a dedicated server that connects two networks having dissimilar
communication protocols.
■The gateways accept the data and message from a computer on a network
having different protocol and it translates and repackages the incoming data
and forwards to another network of the different protocol.
■A gateway is often characterized as being the combination of arouterand a
modem.
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46. Repeater
■Repeater is a device that amplifies the incoming signals, creates a copy of it and
transmits the signal on network.
■It can be used to join two network segments which use the same protocol
Cable
■Cables are commonly used media of physical channel for transmitting data between
computers in network.
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47. MODEM
■MODEM (Modulator Demodulator) is a device which is used to transfer the data of one
computer to another computer using telephone lines.
■It can convert digital signals into analog signals and vice versa.
■The conversion of digital signal into analog signal is Modulation.
■The conversion of analog signal into digital signal is Demodulation.
Importance of MODEMare:
■Access internet
■Perform modulation and demodulation process
■Transfer data from one computer to another through telephone lines.
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48. MODEM
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49. Network Interface Card (NIC)
■A Network Interface Card (NIC) is the adapter through which the computer is
connected to the network.
Function of NIC
■To act as the interface to connect the computer to network and control the flow
of data in computer network.
■To convert data into electronic signals and transfer them through cables and
vice-versa.
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50. Connector
■Connector is an interface between the NIC of the computer and the cable
that passes data between computers in network.
■It is a device that is used to join cables to a device.
■Connectors varies with the cables that we use to connect device in a network.
■BNC(Bayonet NaurConnector),T -Connector, Terminator, RJ-45 are commonly
used in networking.
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51. Device driver
■Device driver is a program that controls the functionality of the hardware device.
Intranet
■An intranet is a private computer network that uses the internet protocol to securely
share any part of information of an organization.
Extranet
■An extranet is a computer network that allows controlled access from outside for
specific business or educational purposes.
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52. Network operating system
■Network operating system is a set of computer program that manages the
resources on network.
Some examples are :
■Novell network
■Microsoft Windows NT
■Linux
■Unix
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53. Any question?
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54. Roshan Maharjan
[email protected]
Networking and
Telecommunication
54