Cisy 231:Data Communications Question Paper
Cisy 231:Data Communications
Course:Computer Science
Institution: Kenya Methodist University question papers
Exam Year:2011
FACULTY : COMPUTING AND INFORMATICS
DEPARTMENT : CIS AND BIT
TIME : 2 HOURS
INSTRUCTIONS Answer Question ONE (compulsory) and any Other TWO Questions
Question 1
a) What three logical topologies are commonly used in Local Area Networks (LANs)? (6marks) b) Describe, compare and contrast Connectionless and Connection-oriented link layer protocols in a distributed network used for business data communications. (6marks)
c) Identify four data communication errors and error correction techniques (8marks)
d) Compare and contrast:
i) Gateways and Firewalls. (2marks)
ii) Half duplex and Full duplex. (2marks)
f) What are standards? (2marks)
i) What are data communications standards used for? (2marks)
ii) State one standard setting organization and the standards It is concerned with (2marks)
Question 2
a) Citing an example state the advantages of using open standards (6marks)
b) How are data communication standards arrived? (4marks)
c) What protocols are used in each layer off the OSI model? (7marks)
d) In Local Area Networks (LANs) the ‘access methodology’ determines how devices share a common physical transmission medium.
e) There are various approaches to used to determine how the sharing of media in wired networks what are the disadvantages of each. (3marks)
Question 3
a) Explain what is meant by the term ‘broadband’ and describe its advantages over traditional dial-up access to the internet. (6marks)
b) State two advantages and two disadvantages of analog data communication.(6marks)
c) What are elements of a computer networks (2marks)
d) What are the advantages of computer networking? (2marks)
e) What are the advantages of the wireless networks over guided networks (4marks)
Question 4
a) For each of the following topologies state the advantages and disadvantages and suggest the most appropriate media access techniques
i) Bus topology
ii) Star topology
iii) Ring topology (12marks)
b) Distinguish between frequency shift keying code division shift Keying from communication. (4marks)
c) A media type used in data communication to as 10 base T has what attributes (4marks)
Question 5
a) State TWO advantages and disadvantages of digital communication. (8marks)
b) For the lower three layers of the ISO Open Systems Interconnection model, name one example of a network device that operates at each layer and briefly explain what it does. (6marks)
c) Parity checks are one of the techniques used in error detection. Briefly explain the following error detection techniques.
i) Longitudinal parity
ii) Simple parity (6marks)
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