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Computer Network

Chapter-1

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Communication channel

  • Communicating data from one location to another requires some form of path or medium. That medium is known

As communication channel.

  • There are two type of communication channel I,e
    1. Guided media(wire medium)
    2. Unguided media(wireless medium)

Communication channel

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Guided media(Wire medium)

  • When we use different cables for data transfer between multiple computers throught a medium, that medium is known as wire medium or guided media.
  • There are three type of cables used in guided media I,e
    1. Twisted paired cable
    2. Co-axial cable
    3. Fiber optics(Optical fiber)Cable

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Twisted paired cable

It is made of plastic insulated which insulate copper wires twisted together to form a single media.

There are two wires, one carries actual data and another used for ground support.

Advantages

Disadvantages

It has low coast and low weight

Signal can’t be transmitted to longer distance due to attenuation.

It is flexible and easily connect.

It has low bandwidth

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Attenuation

the loss of signal strength as it travels through a medium like a cable or wireless connection.

the maximum amount of data that can be transmitted over a network connection in a given amount of time.

Bandwidth

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Co-axial cable

  • It has a single inner conductor that transmits electric signal.
  • It is also known as coax cable.
  • It is primarily used by cable TV companies to connect their satellite antenna facilities to customer homes and businesses.

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Fiber optics cable(Optical fiber cable)

  • It use light for transmission of data.
  • When light hit the critical angle then it reflects 90 degree. This property is known as Total Internal Relaxation.
  • It send data very fast as compare to other cables.
  • It has two mode I,e, one is single mode and multimode fiber.

Single mode:-It carry a single ray of light

Multimode :-It is capable of carrying multiple beams of light.

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Advantages

Disadvantages

It prevent from electrical and magnetic field.

Connecting of two fiber is very difficult.

It is the fasted transmission speed.

It required more protection of it’s core compare to other cable.

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Unguided media(Wireless medium)

  • When data are send without wires, it is known as unguided media or wireless medium.
  • There are three type of transmission wave used in unguided medium I,e,
    1. Radio wave
    2. Micro wave
    3. Infrared waves

Radio wave transmission

  • When two terminals communicate by using radio frequencies then such type of communication is known as Radio wave communication or RF transmission.
  • It has two parts
    • Transmitter
    • receiver

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Transmitter:- The device which transmit signals are called Transmitter.

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Receiver:- The device which received signals, are called as receiver.

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Microwave Transmission

  • It is one of the fastest media of data transmission.
  • It travel data in single direction instead of all direction(Broadcasting).
  • The frequency range is o.3 to 300GHz.
  • It is used in Cellular network and television broadcasting.

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Infrared wave

  • Infrared waves are the high frequency waves used for short-range communication.
  • It can’t penetrate(pass) through the solid-objects.
  • It is used in TV remote, wireless speaker

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Satellite communication

  • Satellite used radio frequency for longer distance transmission.
  • Satellite amplifies signal received from one earth station to another earth station which can be located in many thousands of miles away.
  • It is used in ships,vehicles,planes, etc.

Advantages

Disadvantages

It cover a vast range of area.

It is very costly.

Some area wire connection is impossible to implement, In that are we used satellite communication

There is atmospheric loss of transmitted signals.

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Bluetooth

Bluetooth is a short-range wireless communication technology that allows devices to connect and exchange data without wires.

It is used to create PAN(Personal Area Network).

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Types of network

  • Computer network is divided into three different type based on their geographical area like
    1. PAN(Personal Area Network)
    2. LAN(Local Area Network)
    3. MAN(Metropolitan Area Network)
    4. WAN(Wide Area Network)

PAN

  • It stands for Personal Area Network.
  • It is a computer network present around within a individual person.
  • This network can be constructed either wire or wireless.
  • The range of this network around 10 meter.

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LAN

  • It stands for Local Area Network.
  • This network is create inside office building or home for sharing of files or resources.
  • The rang of this network is a few hundred meter but no more then a mile(1.6 km).
  • The speed of data transmission is from 10mbps to 10Gbps.
  • LAN can be either wire or wireless.
  • It is suitable for bus, ring or star topology.

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MAN

  • It stands for Metropolitan Area Network.
  • It is distributed to a city, college campus or large geographical area.
  • Many LANs are connected to create MAN.
  • This network may be owned and operated by a single organization.
  • It usually cover 5 to 50 km geographical area.

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complete