Techniques of Bandwidth utilization: Multiplexing
What is Bandwidth Utilization?
Bandwidth utilization can be defined as the amount of bandwidth consumed on a network or network segment and the breakdown of its composite traffic.
What is Multiplexing?
Multiplexing refers to multiple sources but one link. In the multiplexing approach, all the devices are connected to MUX and one line to host. The link carries multiple channels of information and the number of lines in it is the same as the number of lines out.
What are the different types of Multiplexers?
The different types of multiplexers are as follows:
- Frequency Division Multiplexing
- Time Division Multiplexing
- Wavelength Division Multiplexing
Frequency Division Multiplexing
The frequency spectrum is divided into logical channels and each user has exclusive access to the channels, it sends signals into different frequency ranges and carries multiple video channels on a single cable. Every signal is modulated onto separate carrier frequencies which are divided by guard bands. All the assignment for non-overlapping frequency ranges from each user or signal on medium. Therefore, all the signals are transmitted at the same time but through different frequencies. The multiplexer accepts inputs and assigns frequency to each device.
Disadvantages of FDM:
It has only one drawback that it cannot utilize the full capacity of the cable.
Time Division Multiplexing
Time Division Multiplexing is generally used in computer communication and telecommunications. In this, the sharing of channels is accomplished by dividing the available transmission time on a medium among the users.
TDM uses digital signalling instead of dividing the cables into frequency bands.
There are two types of TDMs:
- Synchronous Time Division Multiplexing: In this, the multiplexer and the de-multiplexer have to decide on time slots.
- Statistical Time Division Multiplexing: In this, the time division is fixed.
Wavelength Division Multiplexing
WDM is similar to Frequency Division Multiplexing but it is applied to fibers. The only difference between them is that the operating frequencies are much higher than they are in the optical range. It multiplexes multiple data streams onto a single fiber optic line and different wavelength lasers transmit the multiple signals.
It is of two types:
- Dense wavelength division multiplexing: It combines many channels into one fiber.
- Coarse wavelength division multiplexing: It combines fewer channels into one fiber.