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IWT711S - INTERNET AND WAN TELECOMMUNICATIONS - 1ST OPP - JUNE 2025 |
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n Am I 8 I A Un IVERS ITY
OF SCIEnCE Ano TECHnOLOGY
Faculty of Computing and Informatics
Department of Computer Science
QUALIFICATION:Bachelor of Computer Science in Cyber Security
QUALIFICATIONCODE: 07BCCS
COURSE:Internet and WAN Telecommunications
LEVEL: 7
COURSECODE: IWT711S
DATE:June 2025
SESSION: 1
DURATION: 2 hours
MARKS: 70
EXAMINER(S):
MODERATOR:
FIRSTOPPORTUNITYEXAMINATION QUESTION PAPER
Mr. Nasimane Ekandjo
Mr. Kudakwashe Madzima
THIS QUESTIONPAPERCONSISTSOF 5 PAGES
(Excluding this front page)
INSTRUCTIONS
1. Answer ALL the questions.
2. Write clearly and neatly.
3. Number the answers clearly.
4. When answering questions you should be guided by the allocation of
marks. Do not give too few or too many facts in your answers.
PERMISSIBLEMATERIALS
1. None
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Section A [14 marks]
Question 1
For the following questions, answer True/False.
[6]
1.1 10.255.254.1 is an example of a public IP Address.
1.2 In Analog WANs, modems are used to convert digital data to analog and vice versa.
1.3 A CODECis a device that is used to simultaneously perform the analog to digital conversion
(encoding) and digital to analog conversion (decoding).
1.4 The Ethernet cables offer data transmission speed ranging from 10 Mbps to 1000 -
1.5 Single-mode fiber has higher bandwidth and lower attenuation than multi-mode fiber.
1.6 The range of private IP addresses for class A starts from 10.0.0.0 to 10.10.255.255.
Question 2
Choosethe correct answer from the multiple-choice questions below.
[8]
2.1 Which of the following is not true regarding 1Pv6?
a) The header includes the flow label field
b) It has a 128 bit source address and a 128 bit destination address
c) The header includes a "header checksum"
d) It makes use of Hop Limit instead of Time To Live
2.2 The frequency of a signal is usually expressed in
a) hertz
b) volts
c) decibels
d) seconds
2.3 The
wave is the simplest analog signal.
a) periodic
b) digital
c) composite
d) sine
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2.4 Which VPN technology implements confidentiality?
a} ESP
b} MOS
c} ISAKMP
d} AES
2.5 The client knows that it no longer needs an IP address, which DHCP packet type will be sent
to a DHCPserver?
a} DHCP renew
b} DHCP decline
c}
DHCP release
d} DHCP NAK
2.6 Which of the following is the correct network address for the IPv6 node with IPv6 address?
a} 2000:3000:8B74:0130:2E0:8FFF:FE89:1A02/64?
b} 2000::2E0:8FFF:FE89:1A02/64
c} 2000:3000:8B74:0130::/64
d} 2000:3000:8B74:0130:2E0::/64
2.7 ___
will control speed and timing of WAN communication?
a} SDLC
b} DCE
c} HDLC
d} DTE
2.8 Terrestrial microwave communication can use ___
for transmission.
a} repeaters
b} parabolic dish antenna
c} aperture antenna
d} all of the above
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Section B (56 marks]
Question 3
Define the following concepts as used in communication networks.
3.1 Delay distortion
[2]
3.2 Circuit switching
[2]
Question 4
4.1 What is unguided media?
[2]
4.2 How do radio waves differ from microwaves in transmission?
[2]
Question 5
5.1 How does Synchronous TOM differ from Asynchronous TOM?
[4]
5.2 For each of the following types of multiplexing, provide a real-world application/scenario
example.
[3]
FDM: ______
_
TOM: ______
_
WDM: _____
_
5.3 What is the role of a multiplexer and a demultiplexer?
[2]
Question 6
6.1 Name and explain the three types of VPN.
[6]
6.2 IPsec is one of the protocols that can be used in VPNs. Explain any two benefits of IPsec.
[2]
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Question 7
7.1 Why must a satellite have distinct uplink and downlink frequencies?
[2]
7.2 What factors determine antenna gain?
[2]
7.3 What is the primary cause of signal loss in satellite communications?
[2]
Question 8
What are the roles of the following MPLSrouters?
8.1 Label Edge Router (LER)or "ingress node".
[2]
8.2 Label Switching Router (LSR)or "transit node"
[2]
8.3 EgressNode
[2]
Question 9
9.1 Give a sample Cisco IOS command that will forward TCP port 80 on public IP 198.51.100.1
to internal server 10.0.0.10.
[3]
9.2 Outline two benefits and two drawbacks of NAT.
[4]
Question 10
10.1 There is a maximum data transmission distance limit when using UPTcables. What is the
maximum distance limit for CAT6?
[1]
10.2 What is the difference between multi-mode and single-mode fiber-optic cable?
[2]
10.3 Which type twisted pair cable will you use to connect:
a) Switch to switch
[1]
b) PCto router
[1]
b) PCto switch
[1]
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Question 11
Consider the figure below and answer the questions that follow:
Ja<J/Q';-,
1841 C) SC':0/0/l
8r1111chl
DHCP
(°' VLAN1Sand25
-./'C:. (9 ~0/0/ 1--...:::
FfJ0/0
184 l
HQ
F60/1
---I~
PC-Pi
Internet PC
~<>P' T
VlANlS•PC
,
PC-PT
VLAN2S-PC
HQ router is used as a DCHPserver for VLANs 15 and 25. Suppose the networks 192.168.25.192/27
and 192.168.25.224/27 are used for VLAN 15 and 25 respectively.
The gateways for all the routers are configured with the last usable IP Address for each subnets.
11.1 Which IP address are you going to use for VLAN 15 gateway?
[1]
11.2 State the network, subnet mask and gateway that is configured on the HQ router for
VLAN25
[3]
11.3 Which address/es will be excluded from automatic assignment for VLAN 15 and VLAN25?
[2]
End of Paper
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