NATIONAL OPEN UNIVERSITY OF NIGERIA

UNIVERSITY VILLAGE, PLOT 91, CASDASTRAL ZONE, NNAMDI AZIKIWE EXPRESS WAY, JABI, ABUJA.
FACULTY OF SCIENCES
OCTOBER 2019 EXAMINATION

COURSE CODE: CIT305
COURSE CREDIT: 3
COURSE TITLE: NETWORKING AND COMMUNICATION TECHNOLOGY TIME ALLOWED: 21/2 HOURS
INSTRUCTION: ANSWER QUESTION ONE (1) AND ANY OTHER (4) QUESTIONS

QUESTION ONE
1a.A common model in Networking and Communication Technology, is the Open System Interconnection (OSI) model. Produce a table of the OSI model from the topmost layer
the bottom layer, depicting each of the following:
i. The number of each layer (3 1/2 marks)
ii. The name of each layer (3 1/2 marks)
iii. The main function of each layer (7 marks)
(14 marks)
1b.Demonstrate the application of multiplexing within the following contexts:
i. Telephony (2 marks)
ii. Video processing (2 marks)
iii. Digital broadcasting (2 marks)
(6 marks)
1c.Establish a clear distinction between a digital system and a non-digital system
(2 marks)
[Total = 22 marls]

QUESTION TWO
2a. Name and briefly discuss the three (3) common forms of transmission impairment in digital signals. (6marks)
2b. Generally, the Integrated Services Digital Network’ (ISDN) Standards define three basic types of channels. Identify and give a brief explanation of these channels.
(6 marks)
[Total = 12 marks]

QUESTION THREE
3. Efficient network security is required for corporations, universities, schools, publiclibraries, internet cafes and other applications where administrator has to secure and maintain a lot of network workstations located in different places. Outline and briefly deliberate on any six (6) strategies for ensuring efficient network security.
(12 marks)

QUESTION FOUR
4a.Write short notes on the following:
i. GSM and GPRS
ii. Power Over Ethernet(POE) ) 2 marks each; 2 x 3 = 6 marks
iii. Radio Modems
4b.Give a brief explanation of the followig :
i. Space Division Multiplexing
ii. Time Division Multiplexing
iii. Code Division Multiplexing ) ) 2 marks each; 2 x 3 = 6 marks
[Total = 12 marks]

QUESTION FIVE
5a. Synchronous Optical Networking also known as SONET, establishes the end-to-end connection as being composed of three (3) different equipment layers.
State and briefly illustrate the role of each of these equipment layers. ( 9 marks)
5b. The TCP/IP protocol suite has two sets of protocols at the internet layer, Write down and designate the main purpose of these two sets of protocols( 3 marks)
[Total = 12 marks]

QUESTION SIX
6a. All digital information possess common properties that distinguish them from analog communications methods. Write down and analyse any four (4) of these properties ( 8 marks)
6b. Write a short note on the concept of “Packet Switching” (4 marks)
[Total = 12 marks]