NATIONAL OPEN UNIVERSITY OF NIGERIA

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

COURSE CODE: DAM361

COURSE TITLE: BUSINESS COMMUNICATION AND NETWORKS

CREDIT UNIT: 2

TIME ALLOWED : 2 Hours

INSTRUCTION: ANSWER QUESTION ONE (1) AND ANY THREE OTHERS

1 a. What is transmission medium/media? (1mark)

b. Explain with examples of two types of transmission media (6marks)

c. What is MAC address and IP address? (1mark)

d. Differentiate between MAC address and IP address (3marks)

e. What is difference between The Internet and The Web? (1marks)

f. Historically, how did TCP/IP emerged? (3marks)

g. Indicate the meaning of the acronym of the common protocols of TCP/IP - HTTP, HTTPS, FTP. (3marks)

h. You have been allocated a class A network address of 29.0.0.0. You need to create at least 20 networks and each network will support a maximum of 160 hosts. Would the following two subnet masks - 255.255.0.0 and or 255.255.255.0- work? (3marks)

i. What are these three forms of business organizations that are recognized in Nigeria? Provide a definition of each of the forms of the business organization you specified (4marks)

1. sole proprietorship

2. general partnership

3. corporation

4. limited liability company

Question 2

a. Explain the types of networking media would be most appropriate for the following scenarios and justify the reasons for selecting it. (4 marks)

b. An IT research lab researching big data search and storage solutions with data center research facilities located across a large geographic area (4 marks)

c. A festival venue based at a farm with a fixed broadband connection, where several thousand festival goers attend a festival several times a year and for the remaining time the fields are used for sheep grazing (4 marks)

d. Explain and justify which IP routing protocol is best for WAN connectivity in a scenario where two large organization either by merge or acquisition become one organization with different vendor’s routers and they want to minimize the impact of routing changes between the organizations (3 marks)

Question 3:

a. Briefly discuss the functions of each of the following terms and explain their relationship to WAN connectivity.

i. DCE (Data Communications Equipment) (2marks)

ii. DTE (Data Termination Equipment) (2marks)

iii. CSU/DSU/NTU (Channel Service Unit/Data Service Unit/Network Terminating Unit) (3marks)

iv. CPE (Customer Premises Equipment) (2marks)

v.. Demarcation point - Also called point of demarcation (POD) (2marks)

vi. Local loop (1mark)

b.. Discuss why fiber optic cables are more suitable than copper wired or wireless media for high voltage AC environments. (3marks)

Question 4

a.. Explain the key protocol and operational differences between Ethernet (IEE 802.3) and Wireless LAN’s (IEEE80.11) (3marks)

b. Study the diagram provided and answer each of the following question

i. Given that the subnet mask used in the scenario is /24: Explain which IP addresses can be assigned and the ones not assigned to the computers or hosts in both the left and right side of the router R and indicate why? (5marks)

ii. Which IP addresses can be assigned to the left and right interfaces interface of the router R (2marks)

iii. Suppose computer A wants to send an IP datagram to computer B and knows B’s IP address. Does computer A need to know computer B’s MAC address to send the datagram to computer B? If yes, explain the operation used by A to obtain B’s MAC address. If not, explain why not and what information would be used for the datagram to arrive to computer B. (3marks)

iv. Suppose computer A wants to send an IP datagram to computer C and knows C’s IP address. Does computer A also need to know C’s MAC address to send the datagram to computer C? If yes, explain the operation used by A to obtain C’s MAC address. If not, explain why not and what information would be used for the datagram to arrive to computer C. (2marks)

Question 5

a. How can you identify the IP class of a given IP address? (4marks)

b. Given the following protocols, indicate in which layer of the TCP/IP protocol architecture each can be found? (3marks)

i. Ethernet

ii. SMTP

iii. Optical fiber c. What is Domain Name Service (DNS). (3marks)

d. How DNS queries are resolved in the DNS system with recursive and iterative queries (2marks)

e. What is the difference between Network Hub, Network Switch, and Network Router? (3marks)