Computer Networks Y3s1 2009 Question Paper
Computer Networks Y3s1 2009
Course:Bachelor Of Computer Science
Institution: Kabarak University question papers
Exam Year:2009
COURSE CODE: COMP 312
COURSE TITLE: COMPUTER NETWORKS
STREAM: Y3S1
DAY: WEDNESDAY
TIME: 9.00 – 11.00 A.M.
DATE: 02/12/2009
INSTRUCTIONS:
1. This question paper has FIVE questions
2. Answer question ONE and any other TWO questions
QUESTION ONE (30 MARKS) COMPULSORY
(a) Explain the meaning of following terms
i. CRC
ii. PCMCIA
iii. Shannon’s theorem (6mks)
(b) Distinguish between
i. Data encryption and data decryption
ii. Wifi and WiMAX (4mks)
(a) Illustrate the difference between TCP/IP and OSI reference model layer systems
(4mks)
(c) Explain three ways in a computer network is more efficient than other networks
(3mks)
(d) Demand priority Access method distinguishes four priority class levels in
controlling data access to a network. List and explain the four access classes.
(4mks)
(e) Consider the IP address: 173.192.173.192
i. Identify the network class, network id, host id and correct sub netting
(2mks)
ii. Convert 17310 and 19210 parts to binary number system
(4mks)
iii. Why is it advisable not to allocate this address to a network node?
(3mks)
QUESTION TWO (20 MARKS) ELECTIVE
(a) Compare and contrast hubs and switches (4mks)
(b) As a network designer, you are tendered to design a network for a army barrack zone.
Between coaxial, twisted cable and fibre optic cables, which cabling would you
prefer? Explain five issues for your preference (10mks)
(a) A 10dB noisy medium transmits signals between 75 MHz and 85 MHz frequencies.
Determine the maximum data capacity the channel can transmit. (6mks)
QUESTION THREE (20 MARKS) ELECTIVE
(a) What is clock synchronization? (2mks)
(b) Clock synchronization in Non-Return to Zero encoding scheme is hard to
achieve. Explain (3mks)
(c) Data encoding techniques include ASCII, Non-Return to Zero, and Manchester.
Discus Manchester encoding system including at least one advantage and one
disadvantage (5mks)
(d) Plot a Differential Manchester encoding scheme graph for the ASCII extended
coding for the two letters aB (10mks)
QUESTION FOUR (20 MARKS) ELECTIVE
(a) IP address is classified as class A, B, C, D and E. Is it necessary to classify IP
addresses into these classes? Explain (2mks)
(b) Explain two importance of sub netting network IP addresses (4mks)
(c) Explain the difference between a class ‘B’ and a class ‘C’ IP addresses (8mks)
(d) A network that uses ASCII coding system transmits the word Bad! Across it’s
network. Determine the checksum of the word Bad! (6mks)
QUESTION FIVE (20 MARKS) ELECTIVE
(a) Explain the meaning of the term ping as used in networking (2mks)
(b) Your are called upon to set up a peer-to-peer connection. One of the computer’s
IP address is 175.168.125.10 and the other node’s IP address is 193.128.16.10.
i. Describe the steps you have to take to configure the IP address is
193.128.16.10 (6mks)
ii. Do you think that the two computers communicated? Explain (3mks)
(c) List any four threats to a network security (4mks)
(d) Choosing an administrative password is one of the easiest and least expensive ways
to guard against unauthorized access. Unfortunately, too many people prefer to use
an easy to remember password. Discuss five characteristics of a good and secure
password.
(5mks)
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