Computer Science (Paper-II)
5. Networking Technology
Network /Computer Network
A computer network is a group of interconnected nodes or computing devices which
can share resources and services.
Networking
- The concept of sharing resources and Services is called Networking.
- Resources can be data Scanner, a modem and a printer, and
- Services can be e-mail service databases etc.
- All the systems connected through a pathway called as transmission media.
- Transmission media uses a set of communication rule called as Protocols.
Transmission media
Transmission media is a pathway through which systems are connected and also it
is used to transmit electronic signals (Binary pulses i.e. on/off) from one computer to
another.
Transmission of data
Transmission media transmit Binary pulses i.e, electronic signals through
frequencies. Different media are used for different frequencies.
The frequencies used to transmit data or signals
- There are three types frequencies used to transmit data or signals
1. Radio frequency
2. Infrared Light Frequency
3. Microwave frequency
1. Radio frequency:-
It uses for short distance i.e. it is used in local area network i.e. LAN and transmit
data using twisted pair or co-axial cable.
2. Infrared Light Frequency:-
It uses for short distance, within 100 feet and transmit data using Fiber-optic cable.
eg:- Remote control of T.V uses infrared light frequency.
3. Microwave frequency:-
It uses for long distance. ie it is used to transmit data between earth stations and
between earth stations and satellites. It transmits data using fiber optic cable.
Transmission media characteristics
1) Cost 2) Installation Requirement 3) Band width
4) Band usage 5) EMI 6) Attenuation
,1) Cost:-
Cost is important factor to purchase transmission media. If you want fastest then it will be
more expensive. Network designer suggest inexpensive and strong.
2) Installation Requirement:-
Some transmission media you can install at home but some needs. Skilled person so it
increases cost of network and also takes some time to install.
3) Band width:-
A Band width is the capacity of medium to transmit data (bits) per
Second. If an network transmit 20 million bits per second then its band width will be
20mbps (megabits per second)
4) Band Usage: -
Band usage means band uses by network i.e Base Band or Broad Band.
Base band uses only one Communication channel whereas broad band uses multiple
communication channel
5) Attenuation :-
Attenuation is used to measure how much signals becomes weak when it travels through a
medium. Here, Repeaters are used to regenerate signals.
6) Electromagnetic Interference (EMI):-
EMI means outsider disturbance which affects the signals in a medium.
eg:- cross talk (it occurs when signal from one wire is picked by another wire.)
Multiplexing
Multiplexing means combining multiple data channels for transmission on a common
medium.
De-multiplexing
De-multiplexing means recovering the original separate channel from a multiplexed signal.
Multiplexing useful under following conditions/circumstances
- When media band width is costly.
- When band width is idle.
- When large amount of data must be transmitted through low capacity channels.
Types of multiplexing
- There are two types of multiplexing:
1. FDM (Frequency Division Multiplexing)
2. TDM (Time Division Multiplexing)
, 1. FDM (Frequency Division Multiplexing):-
- The technique of dividing bandwidth into frequency bands is called frequency
division multiplexing (FDM))
- FDM works only with analog signals.
- In FDM all data channels are converted to analog form.
- Each analog signal is modulated by a separate frequency called carrier frequency. At
receiving end the de-multiplexer can select signal and recovers the data signal.
- In FDM bidirectional signaling is also possible on same cable.
Fig. Frequency Division Multiplexing
2. TDM (Time Division multiplexing)
- TDM divides a channel into time slots that are allocated to the data streams to be
transmitted.
- TDM Works with digital signals.
- For recovering original data signals the sender and receiver should agree on time
slots.
Fig. Time Division Multiplexing
Types of transmission media
I. Cable(Wired) Media/Bounded/Guided transmission media
II. Wireless Media/Unbounded/Unguided transmission media
5. Networking Technology
Network /Computer Network
A computer network is a group of interconnected nodes or computing devices which
can share resources and services.
Networking
- The concept of sharing resources and Services is called Networking.
- Resources can be data Scanner, a modem and a printer, and
- Services can be e-mail service databases etc.
- All the systems connected through a pathway called as transmission media.
- Transmission media uses a set of communication rule called as Protocols.
Transmission media
Transmission media is a pathway through which systems are connected and also it
is used to transmit electronic signals (Binary pulses i.e. on/off) from one computer to
another.
Transmission of data
Transmission media transmit Binary pulses i.e, electronic signals through
frequencies. Different media are used for different frequencies.
The frequencies used to transmit data or signals
- There are three types frequencies used to transmit data or signals
1. Radio frequency
2. Infrared Light Frequency
3. Microwave frequency
1. Radio frequency:-
It uses for short distance i.e. it is used in local area network i.e. LAN and transmit
data using twisted pair or co-axial cable.
2. Infrared Light Frequency:-
It uses for short distance, within 100 feet and transmit data using Fiber-optic cable.
eg:- Remote control of T.V uses infrared light frequency.
3. Microwave frequency:-
It uses for long distance. ie it is used to transmit data between earth stations and
between earth stations and satellites. It transmits data using fiber optic cable.
Transmission media characteristics
1) Cost 2) Installation Requirement 3) Band width
4) Band usage 5) EMI 6) Attenuation
,1) Cost:-
Cost is important factor to purchase transmission media. If you want fastest then it will be
more expensive. Network designer suggest inexpensive and strong.
2) Installation Requirement:-
Some transmission media you can install at home but some needs. Skilled person so it
increases cost of network and also takes some time to install.
3) Band width:-
A Band width is the capacity of medium to transmit data (bits) per
Second. If an network transmit 20 million bits per second then its band width will be
20mbps (megabits per second)
4) Band Usage: -
Band usage means band uses by network i.e Base Band or Broad Band.
Base band uses only one Communication channel whereas broad band uses multiple
communication channel
5) Attenuation :-
Attenuation is used to measure how much signals becomes weak when it travels through a
medium. Here, Repeaters are used to regenerate signals.
6) Electromagnetic Interference (EMI):-
EMI means outsider disturbance which affects the signals in a medium.
eg:- cross talk (it occurs when signal from one wire is picked by another wire.)
Multiplexing
Multiplexing means combining multiple data channels for transmission on a common
medium.
De-multiplexing
De-multiplexing means recovering the original separate channel from a multiplexed signal.
Multiplexing useful under following conditions/circumstances
- When media band width is costly.
- When band width is idle.
- When large amount of data must be transmitted through low capacity channels.
Types of multiplexing
- There are two types of multiplexing:
1. FDM (Frequency Division Multiplexing)
2. TDM (Time Division Multiplexing)
, 1. FDM (Frequency Division Multiplexing):-
- The technique of dividing bandwidth into frequency bands is called frequency
division multiplexing (FDM))
- FDM works only with analog signals.
- In FDM all data channels are converted to analog form.
- Each analog signal is modulated by a separate frequency called carrier frequency. At
receiving end the de-multiplexer can select signal and recovers the data signal.
- In FDM bidirectional signaling is also possible on same cable.
Fig. Frequency Division Multiplexing
2. TDM (Time Division multiplexing)
- TDM divides a channel into time slots that are allocated to the data streams to be
transmitted.
- TDM Works with digital signals.
- For recovering original data signals the sender and receiver should agree on time
slots.
Fig. Time Division Multiplexing
Types of transmission media
I. Cable(Wired) Media/Bounded/Guided transmission media
II. Wireless Media/Unbounded/Unguided transmission media
