Principles Of Data Communications Question Paper
Principles Of Data Communications
Course:Bachelor Of Science In Information Technology
Institution: Kca University question papers
Exam Year:2011
UNIVERSITY EXAMINATIONS: 2010/2011
SECOND YEAR EXAMINATION FOR THE DEGREE OF BACHELOR OF
SCIENCE IN INFORMATION TECHNOLOGY
BIT 2208: PRINCIPLES OF DATA COMMUNICATIONS
DATE: APRIL 2011 TIME: 2 HOURS
INSTRUCTIONS: Answer question ONE and any other TWO questions
QUESTION ONE
a) Briefly describe the following types of noise in data communications:
(i) Thermal noise (2 Marks)
(ii) Inter-modulation Noise (2 Marks)
(iii) Crosstalk (2 Marks)
(iv) Impulse noise (2 Marks)
b) Describe three situations when Satellite communications are more effective than any other means
of communication. (3 Marks)
c) Differentiate between:
(i) Logical and Physical network topologies (2 Marks)
(ii) Broadband and Baseband transmissions (2 Marks)
(iii) Cut-through switching and store-and-forward switching (2 Marks)
d) (i) Define data encoding. (2 Marks)
(ii) Why is it necessary to encode data before transmission? (2 Marks)
(iii) List and briefly describe the trade-offs that one needs to make before encoding data.
(6 Marks)
e) Why is multiplexing important in data communication? (3 Marks)
2
QUESTION TWO
a) (i) Differentiate between single-bit error and burst error. (2 Marks)
(ii) Distinguish between backward error correction and forward error correction. (4 Marks)
b) (i) Define Congestion as it relates to data communication. (2 Marks)
(ii) Discuss any two (2) causes of congestion. (4 Marks)
c) Why is serial transmission commonly used in data communication (5 Marks)
d) Briefly discuss “Signal Spectrum”, “Error detection” and “Cost and Complexity” as factors that
need to be considered when comparing encoding schemes. (3 Marks)
QUESTION THREE
a) Identify and discuss the three (3) steps involved in data communication through circuit switching.
(3 Marks)
b) (i) List three (3) types of signals that wireless LANs use to communicate. (3 Marks)
(ii) Briefly discuss the limitations and challenges of Wireless LANs. (4 Marks)
c) Describe the sequence of events that occur between computer and modem during communication.
(6 Marks)
d) Describe the following types of routers
(i) Internal router (1 Mark)
(ii) Border router (1 Mark)
(iii) External router (1 Mark)
(iv) Dial-up router (1 Mark)
QUESTION FOUR
a) Discuss briefly the importance of error detection and correction, flow control and recovery in data
communications. (8 Marks)
b) (i) Why is routing important in packet-switched networks? (2 Marks)
(ii) What are the primary conditions that affect routing? (2 Marks)
c) Describe the half-duplex (CSMA/CD) access method. (5Marks)
d) State the causes of the following errors and how to prevent them. (3 Marks)
(i) White noise
(ii) Jitter
3
QUESTION FIVE
Due to its recent expansion caused by a higher intake of students, KCA Kisumu campus has been
forced to rent and occupy four (4) floors of a 10-storey building. The campus intends to use the lower
two floors for administration and lecturers’ offices and the third floor for computer labs while the
fourth one dedicated for lecture rooms. The campus also intends to set up a LAN, which is adequately
secure and easy to manage. As the Network Administrator/Engineer:
Required:
(i). What type of network will you set up for the college? (1 Mark)
(ii). You are required to employ sub-netting. Explain how this will be achieved and the
benefits of subnetting. (7 Marks)
(iii). What are the security threats that are likely to occur? Provide a possible solution for
each threat. Note: Provide only three (3) threats. (6 Marks)
(iv). Briefly describe a solution that you will provide for the college for Internet
connectivity. (4 Marks)
(v). Differentiate between “User Authentication” and “User Authorisation”. (2 Marks)
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