2. CONTENTS
C O M P U T E R N E T W O R K
o Introduction of computer network
o The network diagram
o Network media
o Wireless networks
o Summary
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3. INTRODUCTION
C O M P U T E R N E T W O R K
o Computer networking refers to interconnected computing devices that can exchange data and share
resources with each other. These networked devices use a system of rules, called communications
protocols, to transmit information over physical or wireless technologies.
o Nodes and links are the basic building blocks in computer networking. A network node may be data
communication equipment (DCE) such as a modem, hub or, switch, or data terminal equipment (DTE)
such as two or more computers and printers. A link refers to the transmission media connecting two
nodes. Links may be physical, like cable wires or optical fibers, or free space used by wireless
networks.
o In a working computer network, nodes follow a set of rules or protocols that define how to send and
receive electronic data via the links. The computer network architecture defines the design of these
physical and logical components. It provides the specifications for the network’s physical
components, functional organization, protocols, and procedures.
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5. NETWORK MEDIA
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o Transmission media used to link devices to form a
computer network include electrical cable, optical
fiber, and free space.
o A widely adopted family that uses copper and fiber
media in local area network (LAN) technology are
collectively known as Ethernet.
o Wireless LAN standards use radio waves, others use
infrared signals as a transmission medium. Power line
communication uses a building's power cabling to
transmit data.
6. WIRED MEDIA
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o Wired communication media are also known as Guided media and are a type of Transmission media. This
type of communication is most stable which is why it is considered better than wireless. These
connections are less prone to other outer interferences.
o In wired communication media, wire is used to transfer data from source to destination.
o These are also called wired media. Wired media offer high speed, good security and low cost.
o It transmits data in the form of electrical or optical are transmission speed is generally faster. This
Could be through the wire, Fibre optics, vacuums or coaxial cable.
o Wired networks use Ethernet cables to transfer data between connected PSC. In wired media data is
transmitted using three different types of wire which are described below.
o Twisted Pair cable
o Coaxial cable
o Fibre optical cable
7. Twisted pair cable:
It is a popular media for LAN (Local area network) and a telephone network.
It contains multiple pairs of cables twisted with each other .
The cables are twisted to minimize interference between each other.
It is cheaper, lighter thinner more flexible and easier to install. However, it can
transmit data only for a short distance and the transmission speed is slow.
UTP is also the most common cable
used in computer networking.
Twisted-pair cabling is often used in data
networks for short and medium-length
connections because of its relatively
lower costs compared to optical fiber and
coaxial cable.
UTP is now used in some video
applications, primarily in security
cameras.
8. Coaxial cable is commonly used for broadband connections and cable TV networks. It
is appropriate for contacting computers in MAN(Metropolitan Area Network).
It can transmit data at a faster speed for a longer distance than a twisted pair cable.
It is expensive, heavier, thick and difficult to bend compared to twisted pair cable.
It consists of single copper wires covered by a plastic layer and aluminium foil. It
requires a BNC connector to connect the cable with the computer.
One advantage of coaxial over other types of radio transmission line is that in an ideal
coaxial cable the electromagnetic field carrying the signal exists only in the space
between the inner and outer conductors.
COAXIAL CABLE:
9. FIBRE OPTICAL CABLE :
Fibre optics cable is also called optical fibre cable. It is the fastest transmission
media at the present. Fibre optics cable is popularly used for long-distance
communication, telecommunications network.
It transmits data in the form of a light signal. It contains multiple hair -like fibres
made of glass or plastic.
Data is transmitted through the fibre in form of a light signal using the total internal
reflection of light. It requires an ST connector.
10. Wireless media:
The wireless network system is a type of network system in which the
computing devices are connected without using a physical cable/ wire.
They can share data and instructions using radio, microwaves through
the air. The wireless network system can be developed using wireless
transmission media like terrestrial microwave, satellite communication,
Bluetooth connection, and Wi-Fi connection Infrared communication.
11. TERRESTIAL MICROWAVE
C O M P U T E R N E T W O R K
• It is a technology which transmits the focused beam of a radio signal from one ground-based microwave
transmission antenna to another antenna.
• Microwaves are generally an electromagnetic wave which has the frequency in the range from 1GHz to 1000
GHz.
• These are unidirectional waves, whereas the sending and receiving antenna is to be aligned which means the
antennas are narrowly focused.
• Here antennas are mounted on the towers to send a beam to another antenna which is present at km away.
• It works on the line-of-sight transmission, which means the antennas mounted on the towers are at the direct
sight of each other.
• Some of the examples of terrestrial microwave are as follows −
• Used for long distance telephone services.
• Parabolic dish transmitter mounted high.
• Used for both voice and TV transmission.
• Used by common carriers as well as private networks.
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12. SATELLITE COMMUNICATION
• A communications satellite is an artificial satellite that relays and
amplifies radio telecommunication signals via a transponder; it creates
a communication channel between a source transmitter and a receiver
at different locations on Earth.
• The communication satellites are similar to the space mirrors that help us bounce
signals such as radio, internet data, and television from one side of the earth to
another. Three stages are involved, which explain the working of satellite
communications. These are:
• Uplink
• Transponders
• Downlink
• Communications satellites are used for television, telephone, radio, internet,
and military applications
• Communications satellites use a wide range of radio and microwave frequencies.
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13. BLUETOOTH CONNECTION
• Bluetooth is a short-range wireless technology standard that is used for
exchanging data between fixed and mobile devices over short distances
and building personal area networks (PANs).
• It is mainly used as an alternative to wire connections, to exchange files
between nearby portable devices and connect cell phones and music
players with wireless headphones.
• In the most widely used mode, transmission power is limited to 2.5
milliwatts, giving it a very short range of up to 10 metres (33 ft).
• Wireless control and communication between a mobile phone and a
handsfree headset. This was one of the earliest applications to become
popular.
• Wireless control of and communication between a mobile phone and a
Bluetooth compatible car stereo system (and sometimes between the SIM
card and the car phone
• Wireless communication between a smartphone and a smart lock for
unlocking doors.
• Wireless control of and communication with iOS and Android device
phones, tablets and portable wireless speakers.
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14. • WI-FI is a family of wireless network protocols, based on the IEEE 802.11
family of standards, which are commonly used for local area networking of
devices and Internet access, allowing nearby digital devices to exchange
data by radio waves.
• These are the most widely used computer networks in the world, used
globally in home and small office networks to link desktop and laptop
computers, tablet computers, smartphones, smart TVs, printers, and smart
speakers together and to a wireless router to connect them to the Internet,
and in wireless access points in public places like coffee shops, hotels,
libraries and airports to provide visitors with Internet access for their
mobile devices.
• Wi-Fi technology may be used to provide local network and Internet
access to devices that are within Wi-Fi range of one or more routers that
are connected to the Internet. The coverage of one or more interconnected
access points (hotspots) can extend from an area as small as a few rooms
to as large as many square kilometres (miles)
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WI-FI CONNECTION
