Network Topology, Star topology, ring topology, bus topology, mesh topology. Transmission media. Guided and Unguided transmission media. Wired and wireless medium.

1. Computer Networks
Network Topologies
Date:
Presented By:
Rubal Sagwal
Department of Computer Science,
NIT, Kurukshetra
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2. Contents
• Topology
• Types of Topology
• Transmission Medium
• Guided
• Unguided
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3. Topologies
Types of topologies– Sample Architecture
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4. Topology
• Network topology means how we are arranging elements
of a communication network.
• It could be physical arrangement or logical arrangement.
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5. Physical and Logical Topology
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Physical Topology:
Placement of various
physical components
of a network .
Logical Topology:
Define how data flows
within a network.
Defines the
architecture of the
communication
mechanism for all
nodes in a network.

6. Types of Topologies
Star – Bus – Ring – Tree – Mesh Topology
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7. Star Topology
• Centralized.
• Dedicated point-
to-point link to a
central controller.
• Devices are not
directly linked to
one another.
• Dedicated: link carries
traffic only between the
two devices it connects.
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8. Advantages and Disadvantages of Star Topology
• ADVANTAGES:
Robustness (if one device fails, only that link is affected)
Less expansive.
Less connection needs.
Easy to Install.
Easy fault detection.
• DISADVANTAGES:
If central device failed, entire system is dead.
Doesn’t allow direct traffic between two devices.
The controller act as data exchanger.
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9. Ring Topology
• Each device has a
dedicated point-to-
point connection
with only two
devices.
• Only single pass (first
packet reaches to
destination only then
second can transfer).
• Can be un or bi-
directional.
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10. Advantages and Disadvantages of Ring Topology
• ADVANTAGES:
Easy to install.
Less expensive.
Any node failure doesn’t affect entire system.
• DISADVANTAGES:
If any fault in bus cable then stop entire transmission.
As signal travelled, become week when goes long.
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11. Bus Topology
• Multipoint.
• Link is Backbone to
all the devices.
• Can install limited
number on nodes.
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12. Advantages and Disadvantages of Bus Topology
• ADVANTAGES:
Easy to configure.
Add or delete a device requires changing only two connections.
Fault detection is easy.
• DISADVANTAGES:
Any fault in backbone cable will disable the entire topology.
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13. Mesh Topology
• Dedicated point-to-
point link to every
other device.
• Fully connected.
• Node 1 must be
connected to n-1
nodes, node 2
must be connected
to n-1, finally ‘n’
must be connected
to n-1.
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14. Advantages and Disadvantages of Mesh
Topology
• ADVANTAGES:
No work load (each link caries its own data).
Robust (If one link fails, it doesn’t affect the system).
Privacy and Security (dedicated links).
Fault identification and isolation is easy.
• DISADVANTAGES:
Costly (Cabling and i/o port requires).
Reconnection and new connection are difficult( because one is
connected to all and vice-versa).
Complex.
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15. Selecting the Right Topology
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16. Transmission Media
Types of Transmission Media – Communication Mode
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17. Transmission Medium
• A transmission medium is that can carry information from
a source to a destination.
• For ex: The transmission medium for two people having a
tea conversation is the air.
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18. Transmission
Medium
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Transmission
Medium
Guided
(Wired)
Twisted Pair
Cable
Coaxial Cable
Fibber Optics
Cable
Unguided
(Wireless)
Free Space

19. Guided
• Provide channel (physical) from one device to another.
• Three types:
• Twisted Pair Cable
• Coaxial Cable
• Fiber Optic Cable
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20. 1. Twisted Pair
Cable
• Consist of two
conductors with
each own plastic
insulation, twisted
together.
• One for carry signals
and other for ground
reference.
• Two types:
• Unshielded
• Shielded
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21. Two Types of Twisted Pair Cable
1. Shielded Twisted Pair Cable (STP) 2. Unshielded Twisted Pair Cable (UTP)
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22. Categories of unshielded Twisted Pair
Cables(standards provided by EIA)
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23. Application of Twisted Pair Cables
• Used in telephone lines to provide voice and data
channels.
• For DSL (Digital subscribe lines)
• For LAN
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24. Coaxial Cables
• Carries signal of
higher frequency
ranges than those in
twisted pair cables.
• Central core
conductor of solid
copper wire enclosed
in insulating shield
and then wrapped in
a one more
conductor shield, all
are wrapped in a
outer insulator.
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25. Coaxial Cable Standards
• Categorized by RG (Radio Government) ratings.
• APPLICATIONS:
• telephone networks.
• Cable TV
• Ethernet LAN
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Category Use
RG-59 Cable TV
RG-58 Thin Ethernet
RG-11 Thick Ethernet

26. Fiber-Optic
Cable
• Made of glass or
plastic.
• Transmit signal in
the form of light.
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27. • APPLICATIONS:
• Backbone networks (wide area).
• Some cable TV companies also.
• ADVANTAGES:
• Higher bandwidth.
• Immunity to electromagnetic interference.
• Light weight.
• DISADVANTAGES:
• Cost
• Unidirectional light propagation.
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28. Unguided Media
• Wireless.
• Transport electromagnetic waves.
• Signals are broadcast through free space and thus available to
everyone.
• Unguided signals can travel from the source to destination
through:
1. Ground Propagation
2. Sky Propagation
3. Line-of-sight Propagation
• Wireless transmission waves:
1. Radio waves
2. Microwave
3. Infrared waves
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29. Propagation Methods
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30. Wireless Transmission Waves
1. Radio Waves:
• Omnidirectional, when antenna transmit waves, they
are propagated in all directions.
• A sending antenna send waves, received can be by any
antenna.
• Frequency 3kHz to 1GHz.
• Propagates in sky mode, long distance.
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31. Radio Waves Application:
• Useful in multicasting
• AM and FM radio
• Television
• Cordless phones
Advantages:
• Good for long distance broadcast.
Disadvantage:
• Radio wave band is narrow.
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32. Wireless Transmission Waves
2. Microwave:
• Unidirectional
• Sending and receiving antenna should be aligned
• Frequency 1 GHz to 300GHz
• Wide band
• Antenna should be long, so that no one can interfere.
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33. Microwaves Application:
• Useful in unicast
• Cellular phones
• Satellite networks
Advantages:
• Good for one-to-one communication.
Disadvantage:
• Require huge antennas.
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34. Wireless Transmission Waves
3. Infrared Waves
• Frequency 300GHz to 400THz
• High frequency, can not penetrate walls.
• Antenna should be long, so that no one can interfere.
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35. Infrared Application:
• In short range communication
• Wireless mouse, keyboards, Remotes.
Advantages:
• Good for small range communication
• No interference within a room
Disadvantage:
• Useless for long distance communication.
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36. Thank You!
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