UNIVERSITY EXAMINATIONS: 2017/2018
EXAMINATION FOR THE DEGREE OF BACHELOR OF SCIENCE IN INFORMATION
COMMUNICATION TECHNOLOGY
BCT 3102 PERFORMANCE MODELLING OF COMMUNICATIONS NETWORKS
FULL TIME/PARTTIME
DATE: AUGUST, 2018 TIME: 2 HOURS
INSTRUCTIONS: Answer Question One & ANY OTHER TWO questions.
QUESTION ONE
a) Differentiate between the Fault management and Configuration management. [2 Marks]
b) Describe the main steps and activities in each step of network performance management.
[8 Marks]
c) Explain any two networking tools used by the network administrator to check the network
performance. [4 Marks]
d)
e) Explain the difference between serialization delay and propagation delay indicating the main
factors to consider when setting up a network. [6 Marks]
f) Examine the major applications of utilization metrics [6 Marks]
g) Elaborate on any four network application performance factors [4 Marks]
QUESTION TWO
a) Saruni send some data packet to his friend but the friend did not receive some of the data
packets for the first time. The second time he did not receive any data packet.
i) Give four probable causes of Sarunis’s problems. [4 Marks]
ii) As a network administrator, how would you help him? [2 Marks]
iii) Which tools you use in this case? [6 Marks]
b) Define the term network availability [2 Marks]
c) Explain how latency may affect availability. [6 Marks]
QUESTION THREE
a) Describe the steps and process of performance management of networks
[8 Marks]
b) Explain the various tools used in performance management of networks
[8 Marks]
c) Explain the Little’s Theorem [4 Marks]
QUESTION FOUR
Propagation speed is speed at which a bit travels though the medium from source to destination.
Transmission speed is the speed at which all the bits in a message arrive at the destination.
(difference in arrival time of first and last bit). Latency = Propagation delay + Transmission delay +
Queueing time + Processing time
a) What is the propagation time if the distance between the two points is 12,000 km? Assume
the propagation speed to be 2.4 × 108 m/s in cable. 4 Marks
b) What are the propagation time and the transmission time for a 2.5-kbyte message (an e-mail)
if the bandwidth of the network is 1 Gbps? Assume that the distance between the sender and
the receiver is 12,000 km and that light travels at 2.4 × 108 m/s.
4 Marks
c) What are the propagation time and the transmission time for a 2.5-kbyte message (an e-mail)
if the bandwidth of the network is 1 Gbps? Assume that the distance between the sender and
the receiver is 12,000 km and that light travels at 2.4 × 108 m/s.
4 Marks
d) What are the propagation time and the transmission time for a 5-Mbyte message (an image)
if the bandwidth of the network is 1 Mbps? Assume that the distance between the sender and
the receiver is 12,000 km and that light travels at 2.4 × 108 m/s.
4 Marks
e) A network with bandwidth of 10 Mbps can pass only an average of 12,000 frames per
minute with each frame carrying an average of 10,000 bits. What is the throughput of this
network? 4 Marks
QUESTION FIVE
a) Discuss the various metrics that can be used to measure the performance of networks
[10 Marks]
b) describe the properties of Poisson processes as used in performance modelling and analysis
[10 Marks]
