SIT202 Computer Networks Trimester 2

Running head: SIT202 COMPUTER NETWORKS TRIMESTER 2
SIT202 Computer Networks Trimester 2
Name of the Student
Name of the University
Author’s Note

1
SIT202 COMPUTER NETWORKS TRIMESTER 2
Answer to Question 1 (Chapter 3)
1. What is the bit rate?
Bit rate is defined as the number of bits which is passed at a given point in network in a
specific time period in seconds. Bit rate is measured in multiple of bits / second (Batalla et al.,
2016). The bit rate is used for the data transfer rate and used for discussing details of
transmission technology when it is compared with the technology of transmission for the end
users.
2. If the number of signal level is 8 and the bandwidth is 3 MHz, what is the bit rate?
Bit rate is calculated below:
2 * 3 * log2(8) = 3 mbps
3. Suppose that the signal-to-noise ratio (SNR) is 6 dB. What is the capacity (in bits per second)
if the bandwidth is 3 MHz?
The capacity of the channel is calculated using the following formula:
SNRdb = 10log10SNR
 SNR = 10SNRdb/10
 SNR = 10.6
 3.9810
C = B log2 (1+SNR)
= 3*106 * log23.9810
= 3* 106 * 1.993

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SIT202 COMPUTER NETWORKS TRIMESTER 2
= 6 Mbps
4. Discuss the difference between the data rate and the capacity (e.g., answer why they are
different?)
Data rate is defined as the speed of transferring data between the two devices and it is
measured in mbps.
The capacity is defined as the maximum rate in which the data can be transmitted over
the given link of communication or the channel.
Answer to Question 2 (Chapter 6, 7, 8):
1. Explain the purposes of multiplexing and demultiplexing?
Multiplexing – It is the process of transmission of multiple analog or digital input signal over a
single channel. It can also integrate multiple channels of slow speed into a high speed channel
for transmission of the data packets and utilizing it effectively (Bahareva & Tarasov, 2016). The
use of multiplexing avoids the need of maintenance of multiple lines and thus reducing the
operating cost of a network.
Demultiplexing – It is the process of reconverting a signal that contains multiple stream of
analog or digital signal into original unrelated and separated signals. The demultiplexer is used
for receiving the output signal from multiplexer and converting them back into the original form
as sent by the receiver (Ruffato et al., 2017).
2. Place one of “circuit-switching” and “packet-switching” into the followings sentences
• “...” can further be divided into two subcategories – virtual-circuit approach and datagram
approach. - Packet switching