, ~.

DANI KY UNIVERSITY OF GHANA

(All rights reserved)

B. A.lB.SC INFORMATION TECHNOLOGY, FIRST SEMESTER UNIVERSITY

EXAMINATIONS, 2023

DEPARTMENT OF DISTANCE EDUCATION

DCIT 303: COMPUTER NETWORKS (3 CREDITS)

INSTRUCTION:

ALL Answers Must Be Provided In The Table Below

TIME ALLOWED: ONE AND HALF (1 %) HOURS

1 18 35 52 69 86

2 19 36 53 70 87

3 20 37 54 71 88

4 21 38 55 72 89

5 22 39 56 73 90

6 23 40 57 74 91

7 24 41 58 75 92

8 25 42 59 76 93

9 26 43 60 77 94

10 27 44 61 78 95

11 28 45 62 79 96

12 29 46 63 80 97

13 30 47 64 81 98

14 31 48 65 82 99

15 32 49 66 83 100

16 33 50 67 84

17 34 51 68 85

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1. What Network device monitors, restricts, and modifies data flows passing through it to shield
information, structure, and running status of internal networks from the public network?
A. Router
B. Gateway
C. Switch
D. Firewall

2. Forwarding communication data by the central node in a _ _ topology facilitates network

A. Ring, monitoring
B. Ring, mismanagement
C. Star, mismanagement
D. Star, monitoring

3. What is the basis of the computer network?

A. Forwarding and Routing
B. Switching and Forwarding
C. Routing and Switching
D. Decapsulation and Encapsulation.

4. What is the data payload of a packet?

A. The information segment added before the data payload during packet assembly to
facilitate information transmission
B. The information segment added after the payload to facilitate information
transmission
C. The information to be transmitted
D. A set of nodes that can receive broadcast packets from a node

5. What is the primary function of an AC ?

A. Provide wireless data control services
B. Support the fat AP, fit AP, and cloud-based management modes
C. Provide high-speed, secure, and reliable WLAN services
D. Support plug-and-play

6. OSI stands for _ _ _ __

A. Open systems interconnection
B. Operating systems interface
C. Optical services implementation
D. Open services Internet

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 7. Which layer implements connection-oriented and non-connection-oriented data transmission,
as well as error checking before retransmission?
A. Transport Layer
B. Presentation Layer
C. Data Link Layer
D. Network Layer

8. What is the purpose of the options field in the TCP header?

A. To provide the source and destination IP addresses.
B. To provide the protocol (TCP or UDP).
C. To provide the checksum.
D. To provide additional information, up to 40 bytes long.

9. What is the purpose of an access device in a PPPoE connection?

A. To connect multiple hosts on a network to a remote access concentrator
B. To provide interfaces for application software
C. To broadcast data link layer protocol
D. To provide a local area network technology

10. Which of the following events occur when you access Huawei's official website?
A. The browser invokes HTTP to encapsulate the application layer data.
B. The browser uses TCP to encapsulate the application layer data.
C. The browser transmits the application layer data.
D. The browser parses the application layer data.

11. What is the purpose of a routing device?

A. To store IP addresses
B. To forward packets to a destination subnet
C. To identify a unique network node
D. To identify a unique subnet

12. What are the three pieces of information contained in a route?

A. Destination, mask, outbound interface
B. Outbound interface, next hop, destination
C. Destination, outbound interface, gateway
D. Next hop, mask, destination

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 13. What does a router do after an IP packet matches a specific route?
A. It forwards the packet
B. It selects the best path
C. It installs the route in its IP routing table
D. It determines the forwarding path

14. The purpose of an IP address is _ _ __

A. To select paths on a network along which packets are sent from a source to a
destination.
B. To identify a destination subnet and specify the path for forwarding data packets.
C. To identify a unique network node.
D. To identify a subnet together with a destination IP address.

15. How does a router select the optimal route when multiple routes to the same destination have
the same preference?
A. By comparing the metrics of the two routes
B. By selecting the route with the highest preference
C. By selecting the route with the lowest cost
D. By selecting the route with the lowest metric

16. What is the subnet address of a destination host or router when the destination address is
1.l.l.1 and the mask is 255.255.255.0?
A. l.l.l.1
B. 255.255.255.0
C. 0.0.0.0
D. l.l.l.0

17. What is the command used to specify an outbound interface for a static route on a Huawei
device?
A. [Huawei] ip route-static ip-address nexthop-address
B. [Huawei] ip route-static ip-address {mask I mask-length} nexthop-address
C. [Huawei] ip route-static ip-address {mask I mask-length} interface-type interface-
number
D. [Huawei] ip route-static ip-address {mask I mask-length} interface-type interface-
num ber [nexthop-address]

18. What command is used to specify a next-hop IP address for a static route?
A. ip route-static ip-address mask nexthop-address
B. ip route-static nexthop-address mask ip-address
C. ip route-static ip-address mask-length nexthop-address

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DANI KY
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D. ip route-static nexthop-address ip-address mask-length

19. Which of the following is a possible outbound interface in a route?

A. A physical interface such as a 100M or GE interface
B. A logical interface such as a VLANIF or tunnel interface
C. A summary route
D. A Null interface

20. What is the first step the router takes when selecting the optimal route?
A. Comparing the destinations of specific routes
B. Comparing the metrics of routes
C. Calculating the summarized network address
D. Comparing the preferences of routes

21. What is the CSMAlCD process?

A. Listen before send, listen while sending, stop sending due to collision, and resend
after random delay
B. Listen before send, listen while sending, stop sending due to instability, and resend
after random delay
C. Listen before send, listen while sending, stop sending due to collision, and resend
after specific delay
D. Listen before send, listen while sending, stop sending due to instability, and resend
after specific delay

22. What is the purpose of a NIC?

A. To connect a network device to an external network
B. To uniquely identify a network interface card
C. To forward data through a NIC
D. To broadcast packets to all hosts

23. What are the two types of Ethernet networks mentioned?

A. Early Ethernet and Switch Networking
B. Collision Domain and Broadcast Domain
C. CSMAlCD and All-I MAC Address
D. Hubs and Switches

24. How is a broadcast MAC address formatted?

A. 01-00-00-00-00-00
B. FF-FF-FF-FF-FF-FF

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DANI KY
 c. 00-00-00-00-00-00
D. 11-11-11-11-11-11

25. What is the minimum frame length on an Ethernet network?

A. 46 bytes
B. 64 bytes
C. 1500 bytes
D. 15 18 bytes

26. What does the eighth bit of the fIrst byte indicate in the QUI of a MAC address?
A. The total length of a data frame
B. The protocol type
C. The address type
D. The MAC address

27. What is the reason for the data frame length of 1518 bytes?
A. To meet the minimum frame length of 64 bytes
B. To achieve a tradeoff between transmission efficiency and transmission reliability
C. To prevent the transmission of data over long distances
D. To enable faster transmission of data

28. What does a Layer 2 switch do ifit finds a matching entry in the MAC address table for a
unicast frame?
A. Discards the frame
B. Floods the frame
C. Forwards the frame
D. Searches the MAC address table

29. What is the purpose of the access layer in a campus network?

A. To connect terminals to the campus network
B. To enable data communication between different LANs
C. To store the mapping between MAC addresses and switch interfaces
D. To store the mapping between IP addresses and switch interfaces

30. What are the components of a typical campus network?

A. Routers, switches, and frrewalls
B. Access layer, core layer, and egress layer
C. MAC address table, Ethernet frames, and Ethernet interfaces

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DANI KY
 D. Collision domains and MAC address table

31. What happens when the MAC address table of a Layer 2 switch does not contain an entry
corresponding to the destination MAC address of a frame?
A. The frame is forwarded through the outbound interface in the entry.
B. The switch looks up the MAC address table.
C. The switch floods the frame on all interfaces.
D. Each interface belongs to a different collision domain.
32. What is the lifespan of a MAC address table entry?
A. lOs
B. 30s
C. 60s
D. 300s

33. What type of packet does the switch flood when it cannot find the destination MAC address
of the frame in the MAC address table?
A. Unicast Frame
B. Broadcast Frame
C. ARP Request
D. MAC Address Table

34. How does a host obtain the IP address and MAC address of another host?
A. Through the MAC address table
B. Through the IP address table
C. Through the switch
D. Through DHCP

35. What is the initial state of the ARP cache table of Host I?
A. Empty
B. Full
C. Updated

D. Unavailable

36. What is the purpose of introducing VLAN technology?

A. To ensure network breakdowns
B. To improve network access
C. To reduce the number of PCs on the Ethernet
D. To prevent security risks and broadcast storms

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DANI KY
'-'"

3 7. What problems can larger broadcast domains cause in a network?

A. Improved network processing
B. Security issues
C. Direct communication between devices in different VLANs
D. Faults in one VLAN affecting other VLANs

38. Switchl and Switch2 belong to the network of the same enterprise. What happens ifno
processing is implemented when a frame sent from PC 1 reaches Switch2 through the link
between Switchl and Switch2?
A. Switch2 can identify the VLAN to which the frame belongs
B. Switch2 can determine the local VLAN to which the frame should be sent
C. Switch2 cannot identify the VLAN to which the frame belongs
D. Switch2 can identify the local VLAN to which the frame should be sent
39. What is the purpose of the VLAN tag?
A. To identify the VLAN to which the frame belongs
B. To specify the VLAN to which the frame belongs
C. To identify the switch to which the frame belongs
D. To specify the switch to which the frame belongs

40. Which of the following is the definition of IEEE 802.lQ?

A. A system ofVLAN tagging for Ethernet frames by inserting an 802.lQ tag
B. A method for distinguishing frames of different VLANs
C. A system of data tagging for Ethernet frames
D. A method of VLAN implementation

41. Which of the following is true regarding MAC address-based assignment?

A. A network adm inistrator pre configures the mapping between VLAN IDs and MAC
addresses.
B. A switch adds the VLAN tag carrying the PVID of the interface to the frame.
C. The frame is transmitted in the specified VLAN.
D. An untagged frame arrives at an interface of a switch.

42. What happens if an untagged frame is received by a switch that is using IP subnet-based
assignment?
A. The VLAN tag is added to the frame, mapping the source IP address to the frame.
B. The VLAN tag is added to the frame, mapping the protocol (suite) type to the frame.
C. The frame is discarded.
D. The frame is transmitted in the default VLAN.

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DANI KY
",

43. What is the disadvantage of MAC Address-based VLAN Assignment?

A. It is more secure.
B. It is easy to configure.
C. It is less complex,

D. Malicious PCs can easily forge MAC addresses.

44. What type of interface is used when VLANs do not need to be differentiated?
A. Access interface
B. Trunk interface
C. Hybrid interface
D. User terminal

45. What is used to differentiate frames on a trunk interface?

A. 802.3Q tag
B, 802.1Q tag
C. 802.4Q tag

D. 802.5Q tag

46. What type of communication mode is Layer 2 communication?

A. Inter-VLAN communication
B. Communication between PCs on the same network segment in the same VLAN
C. Communication between Layer 2 switches and Layer 3 devices
D. Communication between Layer 3 devices.

47. What is the function of the Dotlq VLAN tag termination on a sub-interface?
A. To remove VLAN tags from the received packets before forwarding or processing the
packets
B. To add VLAN tags to the packets before forwarding the packets
C. To enable ARP broadcast on a VLAN tag termination sub-interface
D, To allow a VLAN tag termination sub-interface to forward broadcast packets

48. What is the main purpose of a Layer 3 device?

A. To terminate VLAN tags
B. To provide Layer 2 communication services
C. To route packets between different VLANs
D. To provide a default gateway for devices on the same VLAN

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DANI KY
 49. How can the number of required physical interfaces be determined?
A. By connecting a Layer 2 switch to a Layer 3 interface of a Layer 3 device.
B. By using the interface interface-type interface-number. sub-interface number
command.
C. By setting the interface connecting the switch to the router to a trunk interface.
D. By the quantity of the deployed VLANs.
50. What does the PCI do when it fmds that the destination device PC2 is not on its network
segment?
A. It sends the traffic directly to PC2
B. It sends the traffic to its gateway
C. It sends the traffic to its VLANIF interface
D. It sends the traffic to the Layer 3 switch

51. What does NAT allow multiple private IP addresses to do?

A. Access the Internet using the same public IP address
B. Access the local network using the same public IP address
C. Access the Internet using the same local IP address
D. Access the local network using the same local IP address

52. What does PC I determine when it performs calculations based on its local IP address, local
subnet mask, and destination IP address?
A. Whether the packet needs to be forwarded at Layer 3
B. The MAC address of the destination device
C. Whether the destination device is on its network segment
D. The IP address of the destination device

53. What does the switch do after determining that the packet has reached the last hop?
A. Searches its ARP table for the destination IP address
B. Searches its MAC address table for the destination IP address
C. Sends the packet to the routing module for re-encapsulation
D. Sends the packet to the switching module for re-encapsulation

54. What is the purpose of the switching module?

A. To determine the outbound interface of the frame
B. To carry a VLAN tag
C. To search the MAC address table
D. To re-encapsulate the packet

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DANI KY
 55. What is the IP address of a VLANIF interface used for?
A. As the gateway IP address of a PC
B. To remove and add VLAN tags
C. To create a VLANIF interface
D. To display the VLANIF interface view
56. What are the advantages of using Eth-Trunk technology?
A. Increased flexibility
B. Time-consuming troubleshooting
C. Complex configuration
D. Improved network bandwidth
57. What is network reliability?
A. The capability of ensuring nonstop network services when a single point or multiple
points of failure occur on a device or link.
B. The capability of ensuring nonstop network security when a single point or multiple
points of failure occur on a link.
e. The capability of ensuring nonstop network services when only multiple points of
failure occur on a device or link.
D. The capability of ensuring data integrity when only a single point of failure occur on
a device or link.

58. What are the levels of network reliability?

A. Card, device, and link
B. Card, application, and link
C. Device, application, and link
D. Card, device, and application

59. What components make up a modular switch?

A. Chassis, power module, fan module, MPU, SFU, LPU
B. Chassis, power module, fan module, MPU, LPU
C. Chassis, power module, fan module, MPU, SFU
D. Chassis, power module, fan module, SFU, LPU

60. What happens if the active uplink or upstream switch fails on a network with device
redundancy design?
A. All downstream networks are interrupted.
B. The links switch to activelbackup mode.
C. The backup link is switched off.
D. The downstream switch is dual-homed to two upstream switches.

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DANI KY
" .
61. What is the main disadvantage of using manual mode in LAG?
A. All active links forward data and evenly share traffic.
B. Defects of the Manual Mode are minimized.
C. Devices cannot exchange packets.
D. Devices cannot determine whether the peer interface is working properly.
62. What is the purpose of load balancing in an Eth-Trunk?
A. To forward data frames over different links
B. To ensure data frames arrive at the peer end in the same order
C. To evenly distribute the data flows to different member interfaces
D. To ensure that frames of the same flow are transmitted over the same physical link
63. What is an iStack?
A. A logical device consisting of two switches
B. A physical device consisting of two switches
C. A logical device consisting of two firewalls
D. A physical device consisting of two firewalls
64. What can be used to simplify network management and improve network reliability?
A. STP
B. VRRP
C. Eth-Trunk
D. iStack and CSS
65. What type of aggregation mode is used by LACP?
A. Static
B. Packet negotiation
C. Per-flow
D. Bridge MAC
66. What is the purpose of Access Control Lists (ACLs)?
A. To control network access behaviors
B. To prevent network attacks
C. To improve network bandwidth utilization
D. All the above
67. What are the elements that an ACL can match?
A. Source and destination IP addresses
B. Source and destination port numbers
C. Protocol types in IP datagrams
D. All of the above

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DANI KY
,',

68. What is the wildcard used to match the network segment address corresponding to
192.168.1.1/24 ?
A. 0.0.0.0
B. 0.0.0.255
C. 0.0.0.1
D. 0.0.0.254
69. Which type of ACL can be identified using a name and number?
A. Basic ACL
B. Advanced ACL
C. NamedACL
D. User ACL
70. What is the difference between a network mask and a wildcard?
A. A network mask is used to match an IP address, while a wildcard is used to match an
IP address.

B. A wildcard is used to match an IP address, while a network mask is used to match a

network segment.
C. A network mask is used to match an IP address, while a wildcard is used to match a
network segment.

D. A wildcard is used to match a network segment, while a network mask is used to

match an IP address.
71. What is the number range of Basic ACL?
A. 2000 to 2999
B. 3000 to 3999
C. 4000 to 4999
D. 5000 to 5999
72. What type of ACL defines rules based on source and destination IPv4 addresses, IPv4
protocol types, ICMP types, TCP source/destination port numbers, and UDP
source/destination port numbers?
A. User ACL
B. Layer 2 ACL
C. Basic ACL
D. Advanced ACL
73. What does the permit action do when an ACL is used with traffic filtering technology?
A. Rejects traffic
B. Stops matching
C. Allows traffic to pass
D. Returns the result "negative match"

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DANI KY
,',

74. What is the difference between "auto" and "config" matching orders?
A. Auto is simpler and config is more complicated
B. Auto matches packets against rules in ascending order of rule ID and config matches
packets against rules in descending order of precision
C. Config matches packets against rules in ascending order of rule ID and auto matches
packets against rules in descending order of precision
D. Auto matches packets against rules in descending order of precision and config
matches packets against rules in ascending order of rule ID

75. What is the command format for the traffic-filter command?

A. traffic-filter acl ac1-number
B. traffic-filter { inbound I outbound} ac1 { ac1-number I name ac1-name }
C. traffic-filter ac1 name ac1-name
D. traffic-filter { inbound I outbound}

76. What command is used to create an advanced ACL?

A. [Huawei] ac1 name ac1-name { advance I ac1-number }
B. [Huawei] ac1 [ number] ac1-number [ match-order config ]
C. [Huawei] ac1 name ac1-name { basic I ac1-number } [match-order config]
D. [Huawei-ac1-basic-2000] rule [ rule-id] { deny I permit}

77. What is the most commonly used protocol to implement AAA?

A. Remote Authentication Dial-In User Service
B. Open Authentication Protocol
C. Authentication, Authorization and Accounting
D. Network Access Control Protocol

78. What is required for a user to access the network?

A. Authentication
B. Authorization
C. Accounting
D. Domain name

79. What is the main disadvantage of local authentication?

A. It requires expensive hardware
B. It takes too long to process
C. The amount of stored information is limited
D. It is not secure

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DANI KY
,',

80. What type of authentication uses a RADIUS or HWTACACS server?

A. Non-authentication
B. Local authentication
C. Remote authentication
D. HWTACACS
81. What are the three authorization modes supported by AAA?
A. Remote authorization, local authorization, non-authorization
B. Non-authorization, Standard authorization, Remote authorization
C. Remote authorization, local authorization, Standard authorization
D. Local Authorization, Standard authorization, non-authorization
82. What are the port numbers used by RADIUS?
A. 1813 and 1812
B. 1813 and 1815
C. 1814 and 1812
D. 1815 and 1813

83. What is the last step of the message exchange process between the RADIUS server and
client?
A. User initiates a connection request.
B. RADIUS client sends an authentication request to the RADIUS server.
C. RADIUS server sends an Accounting-Response (Stop) packet.
D. User sends a logout request.

84. In local authentication and authorization, what happens when the authentication succeeds on
the Router?
A. The user is granted Internet access permission
B. The Router sends the username and password to the RADIUS server
C. The network administrator is granted certain permissions
D. The RADIUS server records the user's network resource utilization

85. What command is used to display the configuration ofa domain?

A. [Huawei-aaa] local-user user-name privilege level level
B. [Huawei-aaa] local-user user-name service-type { { terminal I te1net I fip I ssh I snmp I
http }
C. [Huawei-aaa] domain domain-name
D. display domain [name domain-name]

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DANI KY
 86. What command is used to bind the authentication scheme to the domain?
A. [Huawei-aaa] authentication-scheme authentication-scheme-name
B. [Huawei-aaa] domain domain-name
C. [Huawei-aaa] local-user user-name service-type
D. [Huawei-aaa] local-user user-name privilege level

87. What is the main benefit of using NAT at the network egress?
A. To improve public IP address utilization
B. To enable hosts on an external network to access an internal network
C. To improve the security of the internal network
D. To reduce the number of required public IPv4 addresses

88. What is the range of Class A private IP addresses?

A. 10.0.0.0-172.31.255.255
B. 10.0.0.0-10.255.255.255
C. 10.0.0.0-192.168.255.255
D. 172.16.0.0-192.168.255.255

89. What must be configured on the network egress device if a host that uses a private IP address
needs to access the Internet?
A. NAT
B. A route-forwarding protocol
C. A public IP address
D. A software application

90. What type of NAT is used when a private IP address is mapped to a fixed public IP address?
A. Static NAT
B. Dynamic NAT
C. Network Address and Port Translation (NAPT)
D. Easy IP

91. What type of NA T is used when an internal server is mapped to a public network through a
one-to-one mapping between a [public IP address:port number] and a [private IP address:port
number]?
A. Static NAT
B. Dynamic NAT
C. Network Address and Port Translation (NAPT)
D. NAT Server

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DANI KY
 92. What is the difference between Dynamic NAT and NAPT?
A. Dynamic NAT does not translate port numbers, while NAPT does.
B. Dynamic NAT does not involve address pools, while NAPT does.
C. Dynamic NAT translates both IP addresses and port numbers, while NAPT does not.
D. Dynamic NAT uses an interface address as a public address, while NAPT does not.
93. What is the default port number for the FTP server?
A. 1024
B. 20
C. 21
D. 80

94. How does the FTP server respond to the PORT command from the FTP client in active
mode?
A. It opens port P to notify the FTP client.
B. It sends a connection request from port 20 to port P of the FTP client.
C. It sets up a control connection with the FTP client.
D. It sends a connection request from port 21 to a random port of the FTP client.

95. What is the main difference between FTP and TFTP?

A. FTP supports authentication while TFTP doesn't
B. FTP is easier to implement than TFTP
C. TFTP supports larger files than FTP
D. TFTP supports multiple packet formats

96. When does a DHCP client enter the rebinding state?

A. At 50% of the lease
B. At 87.5% of the lease
C. When the DHCP server assigns a new IP address
D. When the DHCP server sends a broadcast DHCP Request packet

97. What does the server do when a URL is entered in the address box of a browser?
A. Obtain the IP address corresponding to the domain name
B. Parse and render the received HTML file
C. Find the locally stored page file
D. Send the page file to the client

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- "

98. What is the difference between the recursive query and the iterative query?
A. The recursive query queries other DNS servers and returns the query result to the
DNS client, whereas the iterative query informs the DNS client of the IP address of
another DNS server.
B. The recursive query queries other DNS servers and returns the query result to the
DNS client, whereas the iterative query stores the mappings between domain names
and IP addresses.
C. The recursive query stores the mappings between domain names and IP addresses,
whereas the iterative query queries other DNS servers and returns the query result to
the DNS client.
D. The recursive query informs the DNS client of the IP address of another DNS server,
whereas the iterative query queries other DNS servers and returns the query result to
the DNS client.

99. What is the purpose of clocks being synchronized on the backup server and clients?
A. To ensure a proper sequence of implementation
B. To know the time when users log in to the system
C. To analyze logs or debug messages
D. To ensure incremental backup between backup server and clients

100. What is the purpose of the NTP protocol?

A. To synchronize the clocks of devices
B. To manually enter commands to change the system time
C. To synchronize the clocks of access controllers
D. To send time information to other hosts

DANI KY

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