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CMN620S - COMMUNICATION NETWORKS - 1ST OPP - NOV 2023 |
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nAm I BIA un IVE RSITY
OF SCIEnCE Ano TECHnOLOGY
Faculty of Computing and Informatics
Department of Computer Science
QUALIFICATION:BACHELOROF COMPUTER SCIENCEIN CYBERSECURITY
BACHELOR OF COMPTER SCIENCE
QUALIFICATIONCODE: 07BCCS; 07BACS; 07BCMS LEVEL:7
COURSE:COMMUNICATION NETWORl<S
COURSECODE: CMN620S
DATE: NOVEMBER 2023
SESSION: PAPER 1
DURATION: 2 HOURS 30 MINUTES
MARKS: 70
EXAMINER{S)
MODERATOR:
FIRSTOPPORTUNITYEXAMINATION QUESTION PAPER
MR. NASIMANE El<ANDJO
MS. LOINI IIYAMBO
MR. EDWARD NEPOLO
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. Non-programmable calculator.
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Question 1
Indicate whether the following statements are true or false.
[6]
1.1 In a cable access network, the responsibility of a Cable Modem Termination System
(CMTS is to translate/convert analog signals sent from the cable modems in many
downstream houses/residents back into digital format.
1.2 The purpose of a DSLAM is a DSL access network is to convert between analog and
digital data.
1.3 In circuit switching, there is no sharing of resources.
1.4 Within an AS, all routers run the same intra-AS routing protocol.
1.5 Secure Sockets Layer {SSL)can be applied of UDP to enhance security.
1.6 An IP address 172.32.0.1 can be issued to a LAN because it is a private IP address.
Question 2
Choose the correct answer from the multiple choice questions below:
[6]
2.1 Which of the following is correct regarding class C address of IP address?
a) Network bits = 22; Host bits = 10
b) Network bits= 26; Host bits= 6
c)
Network bits =24; Host bits =10
d) Network bits = 20; Host bits = 12
2.2 How many usable host IP addresses are available on the 192.168.10.128 /26 network?
a) 30
b) 32
c) 62
d) 64
2.3 What layer will you use to generate the data if you use either Telnet or FTP?
a) Application
b) Transport
c)
Network
d)
Presentation
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2.4 Assuming the default switch configuration, which VLAN range can be added, modified,
and removed on a Cisco switch?
a) 1 through 1002
b) 2 through 1001
c) 1 through 1001
d) 2 through 1002
2.5 Open Shortest Path first (OSPF)disseminates information in the form of __ .
a) anycast
b) unicast
c)
multicast
d) broadcast
2.6 A type of routing protocol that exchanges entire routing tables at regular intervals is ...
a) Link-state
b) Interior Gateway Protocol
c)
Distance vector
d) All of the above
Question 3
Define the following concepts/key words used in communication networks.
3.1 Socket
[2]
3.2 Boundary router
[2]
Question 4
4.1 Differentiate between contiguous and discontiguous network.
[2]
4.2 Discontiguous subnets have several advantages over contiguous subnets. (Yes or No?)
[1]
Question 5
5.1 Explain why a layer 2 cisco switch is regarded as a self-learning device.
[2]
5.2 Explain the concept of flooding that is used by link-layer switches.
[2]
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Question 6
6.1 With a focus on addressing at layer 2 and 3, what destination addresses will be used by
the PCto send data to the server as shown in the figure? Assume that the PCdoes not
know the server's IP address but knows the address of the first hop count. [2]
2~ 24TT
~h_2
t
Server-PT
Server
4.-,.../,J
PC-PT
PC
6.2 Briefly describe the purpose of IEEE802.lQ encapsulation protocol.
[2)
6.3 What is the difference between an access port and a trunk port?
[2]
Question 7
7.1 ISPs are responsible for assigning companies/organisations with IP address
networks/blocks. Where does the ISPs get these IP address networks/blocks from?
[2]
7.2 Name any two Regional Internet Registers (RIRs) that allocates addresses to their
respective regions.
[2]
Question 8
Consider the following figure that illustrates an institutional
switches.
Web
server
network connected by four
To external ____
internet
__{X)
~"'!'
1 Gbps
[D 1 Gbps
Mail
server
1 Gbps
100 Mbps
(fiber)
Electrical Engineering
Computer Science
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Computer Engineering
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Explain three drawbacks that can be identified in the figure above.
[6]
Question 9
Consider the topology below and answer the questions that will follow:
,--------,1 2111
Karl~erg
192.168.0.0 /28
.
...:.....__;/""
PC-PT
l,lorning
2960 24TT
Sw ch3
192.168.20.0 126
...,;___J
PC-PT
l,1ichael
192.168.0.240 /30
192.168.0.248 /30
2fo
Okai.lirara
192.168.30.0 /28
2960-241T
Switch0
2911
Opuwo
Paulina
29o0-24TT
Switch1
9.1 What type of unencrypted router password need to be configured if a user want to
accessthe privileged EXECmode of Okakarara router?
[1]
9.2 A suggested IP address for Morning PC is the last usable IP address within the range.
Write down this IP add address.
[2]
9.3 A suggested IP address for Martha PCis 192.168.10.130. Is this an accepted IP address?
(Yes or No).
[1]
9.4 What default gateway will be configured on Michael PC?
[2]
9.5 A network administrator decides to configure Opuwo router with RIP routing protocol.
Assist her by writing down the networks that she needs to configure.
[3]
9.6 What is the purpose of configuring a routing protocol?
[2]
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Question 10
You are the Network Administrator of a company in Windhoek. The company has just
established new branches in three suburbs. Utulising VLSM, calculate subnets that will meet
the needs of the company. Concider the class B IP address block: 172.18.0.0 /18
• Pioneers park - 3000 users
• Havana - 500 users
• Otjomuise - 60 users
• Eros - 8 users
You are required to re-draw the table below and then fill it in with the necessary information
as per your subnetting.
[20]
Network Name Network Address Usable host range
Pioneerspark
Havana
Otjomuise
Eros
Broadcast
Address
Subnet Mask
Marks distribution:
[1.5 marks for each network address]
[1.5 marks for each host range]
[1 mark for each broadcast address]
[1 mark for each subnet mask]
Total= 20 marks
End of Paper
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