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IWT711S - INTERNET and WAN TELECOM - 2ND OPP - JULY 2022 |
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n Am I BI A u n IVE RSITV
OF SCIEnCE Ano TECHnOLOGY
Faculty of Computing and Informatics
Department of Computer Science
QUALIFICATION:Bachelor of Computer Science in Cyber Security
Bachelor of Compter Science
QUALIFICATIONCODE: 07BCCS;07BACS
LEVEL: 7
COURSE: Internet and WAN Telecommunications
COURSECODE: IWT711S
DATE:July 2022
SESSION: 2
DURATION: 2 hours
MARKS: 70
SECONDOPPORTUNITY/ SUPPLEMENTARYEXAMINATION QUESTION PAPER
EXAMINER(S)
Mr. Nasimane Ekandjo
MODERATOR:
Mr. Kudakwashe Madzima
THIS QUESTION PAPERCONSISTSOF 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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Question 1 [13 Marks)
Section A [13 marks]
Below are multiple choice questions as well as True / False questions. Select the correct answers.
1.1 In a __ _, a wide range of incoming waves is directed to a common point called the focus.
a) repeater
b) parabolic dish antenna
c) satellite
d) Any of the above
1.2
is an analog multiplexing technique usually involving signals in the visible light
frequencies.
a) FDM
b) TDM
c) WDM
d) MDM
1.3 ___
cable carries signals of higher frequency ranges than ____
cable.
a) Twisted-pair; coaxial
b) Twisted-pair; fiber-optic
c)
Coaxial; twisted-pair
d)
Coaxial; fiber-optic
1.4 The purpose of a(n) ___
is to compensate for an attenuated signal loss.
a) amplifier
b) transmitter
c)
antenna
d)
LED
1.5 When making use of audio signals, what is the frequency range of speech?
a) 100 Hz to 7 KHz
b) 100 KHzto 300 KHz
c)
5 Hz to 50 Hz
d) 50 KHzto 70 KHz
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1.6 The ___ wave is the simplest analog signal.
a}
periodic
b}
digital
c}
composite
d}
sine
1.7 In TDM, slots are further divided into __ _
a}
seconds
b} frames
c}
packets
d}
bits
1.8 The frequency of a signal is usually expressed in ___ _
a}
hertz
b} volts
c}
decibels
d}
seconds
1.9 The DHCPNAK is message from the client to the server in response to a DHCPREQUESTT. he
DHCPNAK indicates that the client does not acknowledge the request and does not agree to
lease the specified IP address.
a} False
b} True
1.10 Radio waves are converted to an electrical signal to produce sound.
a} True
b} False
1.11 The IPv6 address 2001:0404:0001:1000:0000:0000:0EF0:BC00, can also be abbreviated
as 2001:0404:0001:1000:0:0:0EF0:BC00.
a} True
b} False
1.12 Outside Local NAT address is an IP address used to translate an outside private IP address.
b} False
b} True
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1.13 A CODECis a device that is used to simultaneously perform the analog to digital conversion
{encoding) and digital to analog conversion {decoding).
a) True
b) False
Section B [57 marks]
Question 2
Explain the following concepts as used in internet and WAN telecommunications:
2.1 Half-duplex
2.2 Impulse noise
[2 marks]
[2 marks]
Question 3
3.1 Explain why do you prefer to utilise ADSL rather than cable modem for internet connectivity?
[3 marks]
3.2 What type of multiplexing method does ADSL utilises?
[1 mark]
3.3 What is the distance range does ADSL scheme provides?
[1 mark]
Question 4
4.1 Explain why you might want to configure VPN in a particular network.
[2 marks]
4.2 Outline three disadvantages of VPN.
[3 marks]
4.3 IPsecis often used to set up VPNs. IPsecis a group of protocols that are used together to set up
encrypted connections between devices. It helps keep data sent over public networks secure.
Mention two primary security protocols that are used by IPsec.
[2 marks]
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Question 5
5.1 Why would a network administrator choose to use an ATM Network?
5.2 What is the size of an ATM payload field?
5.3 Name three advantages for an ATM cell.
[2 marks]
[1 mark]
[3 marks]
5.4 Mention two approaches that are used in establishing an ATM connection.
[2 marks]
Question 6
Differentiate between Time Division Multiplexing and Wavelength Division Multiplexing. [4 marks]
Question 7
Name and explain three causes of transmission impairments.
[6 marks]
Question 8
8.1 State and explain two types of transmission medium.
8.2 Name two varieties of twisted pair transmission medium.
8.3 What is the use of shielding in twisted pair transmission media?
[4 marks]
[2 marks]
[2 marks]
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Question 9
Consider figure 1 below and answer the questions that follow.
Figure1
9.1 Briefly explain the purpose of having a DHCP server inn the topology shown in Figure 17
[2 marks]
9.2 Name the three IP address allocation mechanisms that are supported by DHCP. [3 marks]
9.3 What is the name of the DHCPpacket type/message that is sent by a DHCPclient to the DHCP
server when the client knows that it no longer needs an IP address.
[1 mark]
9.4 What is the default behaviour of Routerl when PC0 requests service from DHCP server and
why?
[2 marks]
9.5 Assume PC0 is configured with IPv4 and PCl is configured with IPv6 or vice-versa; OR both PCs
are configured with IPv6 but the connectivity between the two different networks separated by
the serial link can only route/understand IPv4 traffic. Propose any two ways on how the two
PCscan communicate.
[4 marks]
9.6 Which DHCPconcept will be configured on Router0 so that PC0 can be assigned an IP address
from the DHCPserver? What is the purpose of this concept?
[3 marks]
End of paper
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