NATIONAL OPEN UNIVERSITY OF NIGERIA

UNIVERSITY VILLAGE, PLOT 91, CASDASTRAL ZONE, NNAMDI AZIKIWE EXPRESS WAY, JABI, ABUJA.
FACULTY OF SCIENCES
JANUARY 2021 EXAMINATION

CIT 465 - Network Administration

Credit: 2 units

TIME ALLOWED: 2 Hours

INSTRUCTION: Answer Question 1 and any other THREE (3)

Questions 1a) For four devices in a network, what is the number of cable links required for each of the following topologies:

i. Mesh

ii. Ring

iii. Bus(4 ½ marks)

1b) Define communication protocol. List the elements of a communication protocol (4 ½ marks)

1c) What do you understand by Network Address Translation, and what is its main purpose? (5 marks)

1d) Explain the basic tools used for testing network connectivity. Outline other related services rendered by these tools(4 marks)

1e) Discuss the various ways to shut down a UNIX system (7 marks)

2a) Explain any six responsibilities of the network administrator (9 marks)

2b) State the advantages and disadvantages of the following network topologies

i. Bus (2 marks)

ii. Star (2 marks)

iii. Ring (2 marks)

3a) Outline any eight challenges of system administration (8 marks)

3b)Summarize the functionalities of the transport layer of the 4 - layer TCP/IP communication model (7 marks)

4a)List the OSI reference communication model in the correct sequence (4 marks)

4b) Summarize the functionalities of the Network Interface layer of the TCP/IP model (4 marks) 4c. Identify the likely causes of network services suddenly becoming unavailable (4 marks) 4d. Outline the basic features of a firewall (3 marks)

5a)Differentiate between IPv4 and IPv6 (4 marks)

5b) Define MAC address(2 marks).

5c) Explain the services responsible for the following:

i. Relating Internet Domain Names to IP addresses(1 mark)

ii. Translating IP addresses to MAC addresses (1 mark)

iii. Translating MAC addresses to IP addresses (1 mark)

5d) What do you understand by dual-homed host? (2 marks)

5e) Describe any two categories of security threats to a system (3 marks) 5f) When you are working on a UNIX system and the disk becomes full, identify two main things to look out for (1 mark)