UNIVERSITY EXAMINATIONS: 2014/2015
ORDINARY EXAMINATION FOR THE BACHELOR OF SCIENCE
IN INFORMATION TECHNOLOGY
BBIT 103 BIT 1305 COMPUTER NETWORKS
DATE: DECEMBER, 2014 TIME: 2 HOURS
INSTRUCTIONS: Answer Question ONE and any other TWO
QUESTION ONE: 30 MARKS – 30 COMPULSORY
(a) List and briefly explain any three (3) different ways in which computer
networks differ from each other. [6
Marks]
(b) LAN technologies account for virtually all deployed LANs and specify cabling
and signaling at the physical and data link layers of the OSI reference model.
With reference to the Token Ring Architecture, explain the process of token
passing. [6 Marks]
(c) Describe the five conversion steps that networks have to perform in order to
encapsulate data. [5 Marks]
(d) State any three (3) reasons why TCP/IP is suited for implementations of intranets
and extranets. [3 Marks]
(e)(i) List and briefly describe the main functions of most Network Operating Systems.
[5Marks]
(ii) Describe any three (3) factors that must be taken into account when deciding
what type of Network Operating System (NOS) to install on a network.
[3
Marks]
(f) Differentiate between a switch and a router. [2 Marks]
QUESTION TWO:20 MARKS
(a) Discuss the following motivations for computer networks:
(i) High Reliability [2 Marks]
(ii) Mix and Match [2 Marks]
(b) List four reasons why bandwidth is important in computer networks
[4Marks]
(c) Explain why the four-repeater rule is important in networking
[3Marks]
(d) State any three advantages of wireless networks. [3 Marks]
(e) Briefly:
(i) Describe a peer-to-peer network. [2 Marks]
(ii) Explain the benefits of a peer-to-peer network [2 Marks]
(iii) Explain two benefits of a client/server network. [2 Marks]
QUESTION THREE: 20 MARKS
(a) List four major characteristics of a LAN
[4 Marks]
(b) Define the following terms as used in Computer networks:
(i) Attenuation [1 Mark]
(ii) Noise [1 Mark]
(iii) Distortion [1 Mark]
(iv) Topology [1 Mark]
(v) Protocol [1 Mark]
(c) Briefly discuss the three (3) fundamental characteristics of a data
communication system. [6 Marks]
(d) Outline the five (5) components of a data communication system. [5 Marks]
QUESTION FOUR: 20 MARKS
(a) With the aid of well-labeled diagrams, differentiate between single-mode and
multi-mode fibre optic cables. [6 Marks]
(b) Discuss each of the following Access methods, and give one example of a
network that uses each.
(i) CSMA/CD [2 Marks]
(ii) CSMA/CA [2 Marks]
(iii) Token passing [2 Marks]
(iv) Demand Priority [2 Marks]
(c) A network topology is a physical layout of the network. Discuss the following
topologies, using appropriate diagrams: star, bus and ring. [6 Marks]
QUESTION FIVE:20 MARKS
(a) Discuss the following configuration aspects used when setting up a peer-to-peer
network using TCP/IP:
(i) Workgroup [2 Marks]
(ii) IP Address [2 Marks]
(iii) Subnet mask [2 Marks]
(b) Each media type has its advantages and disadvantages. Outline five important
factors to consider when selecting media for computer networks. [5 Marks]
(c) Briefly explain the motivation for changing IPv4. [4 Marks]
(d) List five major components that make up a LAN [5 Marks]
