Cork Institute of Technology
Bachelor of Science (Honours) in Software Development and Computer
Networking – Stage 3
(NFQ Level 8)
Autumn 2006
Internetworking and Security
(Time: 3 Hours)
Answer any FOUR questions.
All questions carry equal marks.
Examiners: Dr. J. Buckley
Dr. A. Kinsella
Mr. A. McDonald
Q1. a. Outline the operation of NAT in a security device. What perceived problem in the Internet was
NAT originally devised to solve? (6 marks)
b. What does DHCP do? Why is it better than BOOTP? Outline how DHCP operates? Why is
DHCP Relay necessary? (8 marks)
c. DSL is a physical layer technology. Explain. (4 marks)
d. Illustrate the structure of a DSL network, explaining the functions of the three network devices
found in such a network. (7 marks)
Q2. a. There are two access methods available to an ISDN networks, what are they? Outline the
differences? (4 marks)
b. ISDN offers logical channels using TDM on a physical channel, explain? (7 marks)
c. ISDN uses Q.931 signalling. Outline a basic Q.931 message exchange for a successful call-
setup. (10 marks)
d. At the data-link layer, ISDN uses two values to address the end-application on a remote
terminal, what are they? (4 marks)
