Ec8551 communication networks mcq question bank

EC8551 -
COMMUNICATION
NETWORKS
MCQ QUESTION BANK
Jai Ganesh S MCQ QUESTIONS AND ANSWERS

EC8551 – COMMUNICATION NETWORKS
MCQ QUESTION BANK
UNIT – 1
FUNDAMENTALS AND LINK LAYER
1. A local area network (LAN) is defined by _______________.
A) the geometric size of the network
B) the maximum number of hosts in the network
C) the maximum number of hosts in the network and/or the geometric size
of the network
D) the topology of the network
2. The largest geographic area a wide area network (WAN) can span is _______________.
A) a town
B) a state
C) a country
D) the world
3. A proposed standard is elevated to ________ standard status after at least two
successful tries.
A) informational
B) historic
C) draft
D) None of the choices are correct
4. Which of the following is not one of the components of a data communication system?
A) Message
B) Sender
C) Medium
D) All of the choices are correct
5. Which of the following is not one of the characteristics of a data communication
system?
A) Delivery
B) Accuracy
C) Jitter
6. Data can flow only in one direction all of the times in a _________ mode.
A) simplex
B) half-duplex
C) full-duplex
7. Data can flow only in both direction all of the times in a _________ mode.
A) simplex

B) half-duplex
C) full-duplex
8. Which of the following is not one of the network criteria?
A) Performance
B) Reliability
C) Security
9. In a _____________ communication, the media needs to be shared between devices.
A) point-to-point
B) multipoint
C) mesh
10. In a _____________ communication, the media is dedicated.
A) point-to-point
B) multipoint
C) mesh
11. In a fully connected mesh topology with six computers, we need ________ links.
[2marks]
A) 6
B) 36
C) 15
12. In a star topology with six computers, we need ________ links. [2marks]
A) 6
B) 1
C) 5
13. An RFC is labeled ________ if it must be implemented by all Internet systems.
A) required
B) elective
C) recommended
14. In the original ARPANET, _______ were directly connected to each other.
A) interface message processors (IMPs)
B) host computers
C) networks
D) routers
15. _______ was formed to connect universities with no defense ties.
A) ARPANET

B) CSNET
C) NSFNET
D) ANSNET
16. In a frequency-domain plot, the horizontal axis measures the ________.
A) signal amplitude
B) frequency
C) phase
D) time
17. In a time-domain plot, the horizontal axis is a measure of ________.
A) signal amplitude
B) frequency
C) phase
D) time
18. _______ data are continuous and take continuous values.
A) Analog
B) Digital
C) Analog or digital
19. _______ data have discrete states and take discrete values.
A) Analog
B) Digital
C) Analog or digital
20. _____ signals have an infinite number of values in a time interval.
A) Analog
B) Digital
C) Either analog or digital
21. _______ signals can have only a limited number of values in a time interval.
A) Analog
B) Digital
C) Either analog or digital
22. Frequency and period are ______.
A) inverse of each other
B) proportional to each other
C) the same
D) are not related
23. ________is the rate of change with respect to time.
A) Amplitude
B) Time

C) Frequency
D) Phase
24. _______ describes the position of the waveform relative to time 0.
A) Amplitude
B) Time
C) Frequency
D) Phase
25. A simple sine wave can be represented by one single spike in the _____ domain.
A) amplitude
B) time
C) frequency
D) phase
26. As frequency increases, the period ________.
A) decreases
B) increases
C) remains the same
27. ________ is a type of transmission impairment in which the signal loses strength due
to the resistance of the transmission medium.
A) Attenuation
B) Distortion
C) Noise
D) Decibel
28. ________ is a type of transmission impairment in which the signal loses strength due
to the different propagation speeds of each frequency that makes up the signal.
A) Attenuation
B) Distortion
C) Noise
D) Decibel
29. ________ is a type of transmission impairment in which an outside source such as
crosstalk corrupts a signal.
A) Attenuation
B) Distortion
C) Noise
D) Decibel
30. When propagation speed is multiplied by propagation time, we get the ________.
A) throughput
B) wavelength of the signal
C) distortion factor
D) distance a signal or bit has traveled
31. Baseband transmission of a digital signal is possible only if we have a ____ channel.

A) low-pass
B) bandpass
C) low rate
D) high rate
32. If the available channel is a ____ channel, we cannot send a digital signal directly to
the channel.
A) low-pass
B) bandpass
C) low rate
D) high rate
33. For a ______ channel, the Nyquist bit rate formula defines the theoretical maximum
bit rate.
A) noisy
B) noiseless
C) bandpass
D) low-pass
34. For a ______ channel, we need to use the Shannon capacity to find the maximum bit
rate.
A) noisy
B) noiseless
C) bandpass
D) low-pass
35. _________ can impair a signal.
A) Attenuation
B) Distortion
C) Noise
36. Communication at the data-link layer is ___________________.
A) end-to-end
B) node-to-node
C) process-to-process
37. A ________ is a local address. Its jurisdiction is over a local network. [2marks]
A) link-layer address
B) logical address
C) port number
38. If the sender is a host and wants to send a packet to another host on the same
network, the logical address that must be mapped to a physical address is ______.
[2marks]
A) the destination IP address in the datagram header
B) the IP address of the router found in the routing table

C) the source IP address
39. If the sender is a host and wants to send a packet to another host on another
network, the logical address that must be mapped to a physical address is ______.
[2marks]
40. The sender is a router that has received a datagram destined for a host on another
network. The logical address that must be mapped to a physical address is ______.
[2marks]
41. The sender is a router that has received a datagram destined for a host in the same
network. The logical address that must be mapped to a physical address is ______.
[2marks]
C) source IP address
42. An ARP reply is normally _______.
A) broadcast
B) multicast
C) unicast
43. An ARP request is normally _______.
A) broadcast
B) multicast
C) unicast
44. A packet at the data-link layer is normally called a _______.
A) datagram
B) message
C) frame
45. In a ________________ link, the link is not shared between devices.
A) broadcast
B) point-to-point
C) multicast

46. In a ________________ link, the link is shared between many devices.
A) broadcast
B) point-to-point
C) unicast
47. Data-link layer of a broadcast link has __________ sublayer(s).
A) one
B) two
C) no
48. Data-link layer of a point-to-point link has __________ sublayer(s).
A) one
B) two
C) no
49. Media access control can be presented only in a __________ link(s).
A) point-to-point
B) multicast
C) both point-to-point and multicast
50. Which of the following best describes a single-bit error? [2marks]
A) A single bit is inverted
B) A single bit per transmission is inverted
C) A single bit per data unit is inverted
51. Which error detection method uses one's complement arithmetic?
A) Simple parity check
B) Checksum
C) Two-dimensional parity check
D) CRC
52. Which error detection method consists of just one redundant bit per data unit?
A) Two-dimensional parity check
B) CRC
C) Simple parity check
D) Checksum
53. Which error detection method involves polynomials?
A) CRC
B) Simple parity check
C) Two-dimensional parity check
D) Checksum

54. If the ASCII character G is sent and the character D is received, what type of error is
this?
A) Single-bit
B) Multiple-bit
C) Burst
D) Recoverable
55. If the ASCII character H is sent and the character L is received, what type of error is
this?
A) Burst
B) Recoverable
C) Single-bit
D) Multiple-bit
56. In cyclic redundancy checking, what forms the check bits?
A) The remainder
B) The divisor
C) The quotient
D) The dividend
57. In CRC, if the dataword is 111111, the divisor 1010, and the remainder 110, what is
the codeword at the receiver? [2marks]
A) 111111011
B) 1010110
C) 111111110
D) 110111111
58. In CRC, if the dataword is 111111 and the divisor 1010, what is the dividend at the
sender? [2marks]
A) 1111110000
B) 111111000
C) 111111
D) 1111111010
59. At the CRC generator, _______ is (are) added to the dataword after the division
process to create the codeword. [2marks]
A) 0’s
B) 1’s
C) the remainder
D) the divisor
60. The sum of the checksum and data at the receiver is _______ if no error is detected.
[2marks]
A) − 0
B) + 0
C) the complement of the checksum
D) the complement of the dataword

61. In CRC, the quotient at the sender _______.
A) becomes the dividend at the receiver
B) becomes the divisor at the receiver
C) is the remainder
D) is discarded
62. At the CRC checker, _______ means that the dataword is damaged.
A) a string of alternating 1s and 0s
B) a nonzero remainder
C) a string of 0s
63. A codeword of 10 bits has only four 0s, how many terms are in the polynomial
representation of this code? [2marks]
A) 4
B) 6
C) 8
64. In CRC, if the remainder is only three bits, the divisor should be __________ bits.
[2marks]
A) 3
B) 2
C) 4
65. How many bits are in the divisor if we use CRC-8? [2marks]
A) 9
B) 8
C) 10
66. Checksum uses ____________ addition.
A) one’s complement
B) two’s complement
C) three’s complement
67. To detect five errors, the Hamming distance between each pair of codewords should
be at least_________.
A) 5
B) 6
C) 11
68. To correct five errors, the Hamming distance between each pair of codewords
should be at least_________. [2marks]
A) 5
B) 6

C) 11
69. A checksum can _________ errors.
A) only detect
B) only correct
C) both detect and correct
70. Currently _______ is responsible for the management of Internet domain names and
addresses. [2marks]
A) NIC
B) ICANN
C) ISOC
D) IEFE
71. The TCP/IP protocol suite consists of _______ layers.
A) two
B) three
C) five
D) six
72. A router is involved in ____________ layers of the TCP/IP protocol suite.
A) two
B) three
C) four
D) five
73. A link-layer switch is involved in ______________ layers of the TCP/IP protocol suite.
A) two
B) three
C) four
D) five
74. In the TCP/IP protocol suite, which of the following is an application layer protocol?
[2marks]
A) The User Datagram Protocol (UDP)
B) The Internet Protocol (IP)
C) The File Transfer Protocol (FTP)
D) The Transmission Control Protocol (TCP)
75. In the TCP/IP protocol suite, which of the following is a transport-layer protocol?
[2marks]
A) The Internet Control Message Protocol (ICMP)
B) The Internet Protocol (IP)
C) The Address Resolution Protocol (ARP)
D) The Transmission Control Protocol (TCP)

76. In the TCP/IP protocol suite, which of the following is a network layer protocol?
[2marks]
A) The Stream Control Transmission Protocol (SCTP)
B) The Secure Shell (SSH)
C) The Internet Protocol (IP)
D) User Datagram Protocol (UDP)
77. The transport-layer packet in the TCP/IP protocol suite is called _______________.
A) a message
B) a datagram
C) a segment or a user datagram
D) a frame
78. In the TCP/IP protocol suite, the ______ layer is responsible for moving frames from
one hop (node) to the next.
A) physical
B) data-link
C) transport
D) network
79. In the TCP/IP protocol suite, the physical layer is concerned with the movement of
_______ over the physical medium.
A) programs
B) dialogs
C) protocols
D) bits
80. In the TCP/IP protocol suite, a port number is the identifier at the____________.
A) application layer
B) transport layer
C) network layer
D) physical layer
81. In the TCP/IP protocol suite, a logical address is the identifier at the _______________.
A) network layer
B) transport layer
C) data-link layer
D) application layer
82. The_________ layer is responsible for the delivery of a message from one process to
another.
A) physical
B) transport
C) network
D) application
83. The Internet Protocol (IP) is ________ protocol.
A) a reliable
B) a connection-oriented

C) a reliable and connection-oriented
D) an unreliable
84. The application layer in the TCP/IP protocol suite is usually considered to be the
combination of ________layers in the OSI model.
A) application, presentation, and session
B) application, transport, and network
C) application, data-link, and physical
D) network, data-link, and physical
85. In TCP/IP, a message at the application layer is encapsulated in a packet at the
________ layer.
A) network
B) transport
C) data-link
D) physical
86. In TCP/IP, a message at the transport layer is encapsulated in a packet at the ________
layer.
A) network
B) transport
C) data-link
D) physical
87. In TCP/IP, a message belonging to the network layer is decapsulated from a packet
at the ________ layer.
A) network
B) transport
C) data-link
D) physical
88. In TCP/IP, a message belonging to the transport layer is decapsulated from a packet
at the ________ layer.
A) network
B) transport
C) data-link
D) physical
89. In TCP/IP, a logical connection between an entity at the network layer can be made
with another entity at the ________ layer.
A) network
B) transport
C) data-link
D) physical
90. In TCP/IP, a logical connection between an entity at the data-link layer can be made
with another entity at the ________ layer.
A) network
B) transport

C) data-link
D) physical
91. In TCP/IP, a packet at the third layer carries data belonging to the ________ layer and
the header belonging to the _________ layer. [2marks]
A) third; third
B) third; fourth
C) fourth; third
D) fourth; fourth
92. Polar and bipolar encoding are types of _______ coding.
A) line
B) block
C) scrambling
93. ___________ conversion involves three techniques: line coding, block coding, and
scrambling.
A) Analog-to-digital
B) Digital-to-analog
C) Analog-to-analog
D) Digital-to-digital
94. In ______ schemes, the voltage level oscillates between a positive and a negative value
although it may remain at zero level between the two values.
A) polar
B) bipolar
C) nonpolar
95. In _____, the level of the voltage determines the value of the bit. [2marks]
A) NRZ-I
B) NRZ-L
C) NRZ-I or NRZ-L
96. In ______, the change or lack of change in the level of the voltage determines the value
of the bit. [2marks]
A) NRZ-I
B) NRZ-L
C) NRZ-I or NRZ-L
97. The idea of RZ and the idea of NRZ-L are combined into the ________ scheme.
[2marks]
A) Manchester
B) differential Manchester
C) Manchester or differential Manchester

98. The idea of RZ and the idea of NRZ-I are combined into the ________ scheme.
A) Manchester
B) differential Manchester
C) Manchester or differential Manchester
99. In Manchester and differential Manchester encoding, the transition at the middle of
the bit is used for __________. [2marks]
A) bit transfer
B) baud transfer
C) synchronization
100. In _______encoding, we use three levels: positive, zero, and negative.
A) polar
B) bipolar
C) nonpolar
101. The _____ scheme uses data patterns of size 2 and encodes the 2-bit patterns as one
signal element belonging to a four-level signal. [2marks]
A) 4B5B
B) 2B1Q
C) B8ZS
102. _______ encoding has a transition at the middle of each bit.
A) RZ
B) Manchester
C) Differential Manchester
D) All the choices are correct
103. _______ encoding has a transition at the beginning of each 0 bit.
A) RZ
B) Manchester
C) Differential Manchester
104. Which of the following encoding methods does not provide for synchronization?
A) NRZ-L
B) RZ
C) NRZ-I
D) Manchester
105. Which encoding method uses alternating positive and negative values for 1s?
A) NRZ-I
B) RZ
C) Manchester

D) AMI
106. Block coding can help in _______ and _________ at the receiver. [2marks]
A) synchronization and error detection
B) synchronization and attenuation
C) error detection and attenuation
D) error detection and distortion
107. ________ is the process of converting digital data to a digital signal.
A) Block coding
B) Line coding
C) Scrambling
108. _______ provides redundancy to ensure synchronization and inherent error
detection.
A) Block coding
B) Line coding
C) Line coding or block coding
109. ________ is normally referred to as mB/nB coding; it replaces each m-bit group with
an n-bit group. [2marks]
A) Block coding
B) Line coding
C) Scrambling
110. ________ provides synchronization without increasing the number of bits.
A) Scrambling
B) Line coding
C) Block coding
111. Two common scrambling techniques are ________. [2marks]
A) NRZ and RZ
B) AMI and NRZ
C) B8ZS and HDB3
D) Manchester and differential Manchester
112. PCM is an example of _______ conversion.
A) digital-to-digital
B) digital-to-analog
C) analog-to-analog
D) analog-to-digital
113. The most common technique to change an analog signal to digital data is called
__________.
A) PAL

B) PCM
C) sampling
114. The first step in PCM is ________.
A) quantization
B) modulation
C) sampling
115. ______ finds the value of the signal amplitude for each sample; ____ finds the change
from the previous sample. [2marks]
A) DM; PCM
B) PCM; DM
C) DM; CM
ANSWER KEY:
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UNIT – 2
MEDIA ACCESS & INTERNETWORKING
1. HDLC is an acronym for _______.
A) High-Duplex Line Communication
B) Half-Duplex Link Combination
C) High-Level Data Link Control
D) Host Double-Level Circuit
2. The shortest frame in HDLC protocol is usually the _______ frame.
A) information
B) management
C) supervisory
3. The address field of a frame in HDLC protocol contains the address of the _______
station.
A) primary
B) secondary
C) tertiary
D) primary or secondary
4. The HDLC _______ field defines the beginning and end of a frame.
A) control
B) flag
C) FCS
5. What is present in all HDLC control fields?
A) N(R)
B) N(S)
C) Code bits
D) P/F bit
6. According to the PPP transition-phase diagram, options are negotiated in the _______
state.
A) networking
B) terminating
C) establishing
D) authenticating
7. According to the PPP transition-phase diagram, verification of user identification
occurs in the _______ state.
A) networking
B) terminating
C) establishing
D) authenticating

8. In the PPP frame, the _______ field defines the contents of the data field.
A) FCS
B) flag
C) control
D) protocol
9. In the PPP frame, the _______ field is similar to that of the U-frame in HDLC.
A) flag
B) protocol
C) FCS
D) control
10. In the PPP frame, the _______ field has a value of 11111111 to indicate the broadcast
address of HDLC. [2marks]
A) protocol
B) address
C) control
D) FCS
11. In PPP, what is the purpose of LCP packets?
A) Configuration
B) Termination
C) Option negotiation
12. In the PPP frame, the _______ field is for error control.
A) FCS
B) flag
C) control
D) protocol
13. For CHAP authentication, the user takes the system’s _______ and its own _______ to
create a result that is then sent to the system. [2marks]
A) authentication identification; password
B) password; authentication identification
C) challenge value; password
D) password; challenge value
14. In byte stuffing, we need sometimes to add a (an) ___________ in the payload.
A) flag byte
B) ESC byte
C) null byte
15. In bit stuffing, we sometimes need to add an extra ___________ bit in the payload.
A) 0’s
B) 1’s
C) 0’s or 1’s

16. HDLC is a ________ oriented protocol
A) byte
B) bit
C) byte or bit
17. PPP is a ________ oriented protocol
A) byte
B) bit
C) byte or bit
18. In PPP, the address field defines ___________ of the packet.
A) the sender
B) the receiver
C) either the sender or the receiver
19. In PPP, the ___________ field defines the type of payload encapsulated in the frame.
A) address
B) control
C) protocol
20. In PPP, the CHAP protocol uses ____________ steps to authenticate the parties in
communication. [2marks]
A) one
B) two
C) three
21. In the _______ random-access method collision is avoided.
A) CSMA/CD
B) CSMA/CA
C) ALOHA
D) token-passing
22. In the 1-persistent approach, when a station finds an idle line, it _______. [2marks]
A) sends immediately
B) waits 0.1 s before sending
C) waits 1 s before sending
D) waits a time equal to 1 − p seconds before sending
23. _______ requires one primary station and one or more secondary stations.
A) Token ring
B) Reservation
C) Polling

D) CSMA
24. In the p-persistent approach, when a station finds an idle line, it _______. [2marks]
A) sends immediately
B) waits 1 s before sending
C) sends with probability 1 − p
D) sends with probability p
25. The 1-persistent approach can be considered a special case of the p-persistent
approach with p equal to _______. [2marks]
A) 1.0
B) 2.0
C) 0.1
D) 0.5
26. In the reservation access method, if there are 10 stations on a network, then there
are _______ reservation minislots in the reservation frame. [2marks]
A) 10
B) 11
C) 5
D) 9
27. _______ is a controlled-access protocol.
A) FDMA
B) TDMA
C) CSMA
D) Reservation
28. _______ is (are) a channelization protocol.
A) FDMA
B) TDMA
C) CDMA
29. In the _______ random-access method, stations do not sense the medium.
A) CSMA/CA
B) ALOHA
C) CSMA/CD
D) Ethernet
30. Which of the following is an example of a random-access protocol? [2marks]
A) Polling
B) FDMA
C) Token passing
31. Which of the following is an example of a controlled-access protocol? [2marks]
A) CDMA
B) FDMA

C) Token passing
32. The vulnerable time for a pure ALOHA is __________ the one for slotted ALOHA.
A) less than
B) greater than
C) equal to
33. The vulnerable time for CSMA is ___________. [2marks]
A) Tp
B) 2 x Tp
C) 3 x Tp
34. We need RTS and CTS packets in ____________ protocol.
A) CDMA/CA
B) CDMA/CD
C) token-passing
35. In FDMA, we use different ___________ to achieve channelization.
A) frequency ranges
B) time slots
C) codes
D) None of the choices are correct.
36. In CDMA, we use different ___________ to achieve channelization.
A) frequency ranges
B) time slots
C) codes
37. In TDMA, we use different ___________ to achieve channelization.
A) frequency ranges
B) time slots
C) codes
38. Walsh tables are used in _________________.
A) FDMA
B) TDMA
C) CDMA
39. Given the Ethernet address 01011010 00010001 01010101 00011000 10101010
00001111 in binary, what is the address in hexadecimal notation? [2marks]
A) 5A:88:AA:18:55:F0
B) 5A:81:BA:81:AA:0F

C) 5A:18:5A:18:55:0F
D) 5A:11:55:18:AA:0F
40. If an Ethernet destination address is 07:01:02:03:04:05, then this is a ______ address.
A) unicast
B) multicast
C) broadcast
D) either multicast or broadcast
41. If an Ethernet destination address is 08:07:06:05:44:33, then this is a ______ address.
A) unicast
B) multicast
C) broadcast
D) either multicast or broadcast
42. Which of the following could not be an Ethernet multicast destination address?
[2marks]
A) 43:7B:6C:DE:10:00
B) 44:AA:C1:23:45:32
C) 46:56:21:1A:DE:F4
D) 48:32:21:21:4D:34
43. Which of the following could not be an Ethernet unicast destination address?
[2marks]
A) B7:7B:6C:DE:10:00
B) 7B:AA:C1:23:45:32
C) 7C:56:21:1A:DE:F4
D) 83:32:21:21:4D:34
44. The _______ layer of Ethernet consists of the LLC sublayer and the MAC sublayer.
A) data link
B) physical
C) network
45. The _____ sublayer is responsible for the operation of the CSMA/CD access method
and framing.
A) LLC
B) MII
C) MAC
46. Each station on an Ethernet network has a unique _______ address imprinted on its
network interface card (NIC).
A) 16-bit
B) 32-bit
C) 64-bit

47. The minimum frame length for Ethernet is _______bytes.
A) 32
B) 80
C) 128
48. Fast Ethernet has a data rate of ________Mbps.
A) 10
B) 100
C) 1000
D) 10,000
49. In _________, auto negotiation allows two devices to negotiate the mode or data rate of
operation. [2marks]
A) Standard
B) Fast Ethernet
C) Gigabit Ethernet
D) Ten-Gigabit Ethernet
50. Gigabit Ethernet has a data rate of ________Mbps.
A) 10
B) 100
C) 1000
D) 10,000
51. In Ethernet addressing, if the least significant bit of the first byte is 0, the address is
_________.
A) unicast
B) multicast
C) broadcast
52. In Ethernet addressing, if the least significant bit of the first byte is 1, the address is
_________.
A) unicast
B) multicast
C) broadcast
53. In Ethernet addressing, if all the bits are 1s, the address is _________.
A) unicast
B) multicast
C) broadcast
54. In the Ethernet, the _______field is actually added at the physical layer and is not
(formally) part of the frame.
A) CRC
B) preamble

C) address
D) SFD
55. In the Ethernet frame, the _______ field contains error detection information.
A) CRC
B) preamble
C) address
D) SFD
56. Which of the following statements about wired and wireless LANs is correct?
[2marks]
A) Both operate in the lower two layers of the TCP/IP protocol suite.
B) Wired LANs operate in the lower two layers and wireless LANs operate in
the lower three layers of the TCP/IP protocol suite.
C) Wired LANs operate in the lower three layers and wireless LANs operate
in the lower two layers of the TCP/IP protocol suite.
D) Both operate in the lower three layers of the TCP/IP protocol suite.
57. IEEE has defined the specifications for a wireless LAN, called _______, which covers
the physical and data-link layers. [2marks]
A) IEEE 802.3
B) IEEE 802.5
C) IEEE 802.11
D) IEEE 802.2
58. The CSMA/CD algorithm does not work in wireless LAN because [2marks]
A) wireless host does not have enough power to work in a duplex mode.
B) of the hidden station problem.
C) signal fading could prevent a station at one end from hearing a collision at
the other end.
D) all of the choices are correct.
59. In IEEE 802.11, a ___ is made of stationary or mobile wireless stations and an
optional central base station, known as the access point (AP).
A) ESS
B) BSS
C) CSS
60. In IEEE 802.11, a BSS without an AP is called _________.
A) an ad hoc architecture
B) an infrastructure network
C) either an ad hoc architecture or an infrastructure network
61. In IEEE 802.11, a BSS with an AP is sometimes referred to as ____________.
A) an ad hoc architecture
B) an infrastructure network
C) either an ad hoc architecture or an infrastructure network

62. In IEEE 802.11, communication between two stations in two different BSSs usually
occurs via two ________.
A) BSSs
B) ESSs
C) APs
63. In IEEE 802.11, a station with ________ mobility is either stationary (not moving) or
moving only inside a BSS.
A) no-transition
B) BSS-transition
C) ESS-transition
64. In IEEE 802.11, a station with ________mobility can move from one BSS to another,
but the movement is confined inside one ESS.
A) no-transition
B) BSS-transition
C) ESS-transition
65. In IEEE 802.11, a station with ________ mobility can move from one ESS to another.
A) no-transition
B) BSS-transition
C) ESS-transition
66. In IEEE 802.11, distributed coordination function (DCF) uses _______ as the access
method.
A) CSMA/CA
B) CSMA/CD
C) ALOHA
67. In IEEE 802.11, when a frame is going from one station in a BSS to another station in
the same BSS, the address flag is _____.
A) 00
B) 01
C) 10
D) 11
68. In IEEE 802.11, when a frame is coming from an AP and going to a station, the
address flag is _______.
A) 00
B) 01
C) 10
D) 11

69. In IEEE 802.11, when a frame is going from a station to an AP, the address flag is
_____.
A) 00
B) 01
C) 10
D) 11
70. In IEEE 802.11, when a frame is going from one AP to another AP in a wireless
distribution system, the address flag is _____.
A) 00
B) 01
C) 10
D) 11
71. In IEEE 802.11, the access method used in the PCF sublayer is ______.
A) contention
B) controlled
C) polling
72. In IEEE 802.11, the ______ is a time period used for collision avoidance.
A) NAV
B) BSS
C) ESS
73. In IEEE 802.11, the addressing mechanism can include up to ______addresses.
A) four
B) five
C) six
74. The original IEEE 802.11 uses _________.
A) FHSS
B) DSSS
C) OFDM
D) either FHSS or DSSS
75. The IEEE 802.11a uses _________.
A) FHSS
B) DSSS
C) OFDM
76. The IEEE 802.11b uses _________.
A) FHSS
B) DSSS
C) OFDM

77. The IEEE 802.11g uses _________.
A) FHSS
B) DSSS
C) OFDM
78. The IEEE 802.11 FHSS uses ______ modulation.
A) ASK
B) FSK
C) PSK
79. The IEEE 802.11 or IEEE 802.11b DSSS uses ______ modulation.
A) ASK
B) FSK
C) PSK
80. The IEEE 802.11a, IEEE 802.11g, or IEEE 802.11n OFDM uses ______ modulation.
A) ASK
B) FSK
C) PSK
81. Bluetooth is a _______ technology that connects devices (called gadgets) in a small
area.
A) wired LAN
B) wireless LAN
C) VLAN
82. In Bluetooth, multiple ________ form a network called a _________. [2marks]
A) scatternet; piconets
B) piconets: scatternet
C) piconets: bluenet
D) bluenet; scatternet
83. A Bluetooth network consists of _____ primary device(s) and up to ____ secondary
devices. [2marks]
A) one; five
B) five; three
C) two; six
D) one; seven
84. In Bluetooth, the current data rate is ____Mbps.
A) 2
B) 5

C) 11
85. The access method in Bluetooth is ________.
A) FDMA
B) TDD-TDMA
C) CDMA
86. In Bluetooth, the _____ link is used when data integrity is more important than
avoiding latency.
A) SCO
B) ACL
C) ACO
D) SCL
87. Bluetooth uses ______ in the physical layer to avoid interference from other devices
or other networks.
A) DSSS
B) FHSS
C) FDMA
88. Packetizing at the network layer involves ___________________________. [2marks]
A) encapsulating the payload at the source
B) adds a header that contains the source and destination information
C) decapsulating the payload at the destination
89. Routers in the path are not allowed to ___________________________. [2marks]
A) fragment the packet they receive
B) decapsulate the packet
C) change source or destination address
90. The network layer in the Internet provides _________________.
A) comprehensive error and flow control
B) limited error control, but no flow control
C) comprehensive error control but limited flow control
91. In a virtual-circuit approach, the forwarding decision is based on the value of the
_____________ field in the packet header. [2marks]
A) source address
B) destination address
C) label

92. In a datagram approach, the forwarding decision is based on the value of the
_____________ field in the packet header. [2marks]
A) source address
B) destination address
C) label
93. The performance of a network can be measured in terms of ________.
A) delay
B) throughput
C) packet loss
94. Transmission delay (time) is the ratio of______________________. [2marks]
A) transmission rate to packet length
B) transmission rate to distance
C) packet length to transmission rate
D) processing time to transmission rate
95. Propagation delay (time) is the ratio of______________________. [2marks]
A) transmission rate to propagation speed
B) propagation speed to distance
C) packet length to propagation speed
D) distance to propagation speed
96. When the load in the network reaches the network capacity, the packet delay
___________ and the network throughput reaches ______________. [2marks]
A) increases sharply; its minimum
B) increases sharply; its maximum
C) decreases sharply; its minimum
D) decreases sharply; its maximum
97. In open-loop congestion control, policies are applied ____________________.
A) to prevent congestion before it happens
B) to alleviate congestion after it happens
C) to either prevent congestion before it happens or alleviate congestion
after it happens
98. The __________________ technique is one of the open-loop congestion policies.
A) backpressure
B) choke packet
C) implicit signaling
99. The__________________ technique is one of the close-loop congestion policies.
A) acknowledgment policy
B) choke packet
C) discarding policy

100. An IPv4 address is normally represented in base ____ in dotted-decimal notation.
A) 16
B) 256
C) 10
101. In classful addressing, the IPv4 address space is divided into _______ classes.
A) 3
B) 4
C) 5
102. The number of addresses assigned to an organization in classless addressing
_______.
A) can be any number
B) must be a multiple of 256
C) must be a power of 2
103. The first address assigned to an organization in classless addressing _______.
[2marks]
A) must be evenly divisible by the number of addresses in the organization
B) must be divisible by 128
C) must belong to one of the A, B, or C classes
104. In subnetting, the number of addresses in each subnet must _______. [2marks]
A) be a power of 2
B) be a multiple of 128
C) be divisible by 128
105. What is the default prefix length for class A in CIDR notation?
A) 9
B) 8
C) 16
106. What is the default prefix length for class B in CIDR notation?
A) 9
B) 8
C) 16
107. What is the default prefix length for class C in CIDR notation?
A) 24
B) 8

C) 16
108. DHCP is a (an) ___________ layer protocol.
A) application
B) transport
C) network
D) data-link
109. In DHCP, the client uses ________ port and the server uses _________port. [2marks]
A) an ephemeral; a well-known
B) a well-known; a well-known
C) a well-known; an ephemeral
110. DHCP uses the services of _______.
A) UDP
B) TCP
C) IP
111. _________ allows a site to use a set of private addresses for internal communication
and a set of global Internet addresses for communication with the rest of the world.
A) DHCP
B) NAT
C) IMCP
112. The idea of address aggregation was designed to alleviate the increase in routing
table entries when using ________ addressing.
A) classful
B) classless
C) classful or classless
113. The use of hierarchy in routing tables can ________ the size of the routing tables.
A) reduce
B) increase
C) neither reduce nor increase
114. IP is a _________ protocol.
A) connection-oriented unreliable
B) connection-oriented reliable
C) connectionless unreliable
D) connectionless reliable
115. An HLEN value of decimal 10 means _______. [2marks]
A) there are 10 bytes of options

B) there are 10 bytes in the header
C) there are 40 bytes of options
D) there are 40 bytes in the header
116. If the fragment offset has a value of 100, it means that _______.
A) the datagram has not been fragmented
B) the datagram is 100 bytes in size
C) the first byte of the datagram is byte 800
117. What is needed to determine the number of the last byte of a fragment?
A) offset number
B) total length
C) both offset number and the total length
118. The IP header size is _______ bytes long.
A) 20 to 60
B) 20
C) 60
119. Packets in the IP layer are called _________.
A) segments
B) datagrams
C) frames
120. The total length field defines the total length of the datagram _________.
A) including the header
B) excluding the header
C) excluding the option length
121. When a datagram is encapsulated in a frame, the total size of the datagram must be
less than the _______.
A) MUT
B) MAT
C) MTU
122. ICMP is a (an) _________ layer protocol. [2marks]
A) application-layer protocol that helps TCP/IP at the network layer
B) transport-layer protocol that helps TCP/IP at the network layer
C) network-layer protocol
D) data-link layer protocol that helps TCP/IP at the network layer
123. Which of the following is true about ICMP messages?
A) An ICMP error message may be generated for an ICMP error message

B) An ICMP error message may be generated for a fragmented datagram
C) An ICMP error message may be generated for a multicast datagram
124. When a host moves to a new network, its original address is referred to as
__________.
A) home
B) care-of
C) foreign
125. Which of the following addresses are permanent in mobile IP?
A) home
B) care-of
C) foreign
126. To communicate with a remote host, a computer needs to go through __________
phase(s).
A) one
B) two
C) three
127. In mobile IP communication, the first phase is called __________.
A) agent discovery
B) registration
C) data transfer
128. In mobile IP communication, the second phase is called __________.
A) agent discovery
B) registration
C) data transfer
129. In mobile IP communication, the third phase is called __________.
A) agent discovery
B) registration
C) data transfer
130. In mobile IP communication, inefficiency in triangle routing is ________ the one in
double crossing.
A) more severe than
B) less severe than
C) in the same level as

ANSWER KEY:

UNIT – 3
ROUTING
1. An IPv6 address is _________ bits long.
A) 32
B) 64
C) 128
D) 256
2. An IPv6 address consists of ________ bytes (octets).
A) 4
B) 8
C) 16
3. In hexadecimal colon notation, a 128-bit address is divided into _______ sections, each
_____ hexadecimal digits in length. [2marks]
A) 8; 2
B) 8; 3
C) 8; 4
4. An IPv6 address can have up to __________ hexadecimal digits.
A) 16
B) 32
C) 8
5. In IPv6, the _______ field in the base header restricts the lifetime of a datagram.
A) version
B) priority
C) hop limit
6. The _________ in IPv6 is designed to provide special handling for a particular flow of
data.
A) flow label
B) next header
C) hop limit
7. When two computers using IPv6 want to communicate but the packet must pass
through an IPv4 region, which transition strategy should be used? [2marks]
A) tunneling
B) header translation
C) either tunneling or header translation

8. When the majority of the Internet has moved to the IPv6 but some still use IPv4,
which transition strategy should be used? [2marks]
A) tunneling
B) header translation
C) either tunneling or header translation
9. The protocols __________________________ in version 4 are combined into one single
protocol, ICMPv6.
A) ARP and IGMP
B) ICMP and IGMP
C) ICMP, ARP, and IGMP
10. The block prefix for global unicast address in IPv6 is __________.
A) (110)2
B) (101)2
C) (100)2
D) (001)2
11. The global prefix in IPv6 is __________ bits long.
A) 16
B) 32
C) 48
D) 64
12. The subnet identifier in IPv6 is __________ bits long.
A) 16
B) 32
C) 48
D) 64
13. The interface identifier in IPv6 is __________ bits long. [2marks]
A) 16
B) 32
C) 48
D) 64
14. The EUI link-layer (physical) address is _________ bits long. [2marks]
A) 16
B) 32
C) 48
D) 64
15. The MAC address in the Ethernet is_________ bits long.
A) 16
B) 32
C) 48
D) 64

16. Routing inside an autonomous system is referred to as ________ routing.
A) interdomain
B) intradomain
C) out-of-domain
17. Routing between autonomous systems is referred to as ______ routing.
A) interdomain routing
B) intradomain routing
C) out-of-domain
18. In _______ routing, the least cost route between any two nodes is the route with the
minimum distance.
A) path vector
B) distance vector
C) link state
19. In ________, each node maintains a vector (table) of minimum distances to every node.
A) path vector
B) distance vector
C) link state
20. In distance vector routing, each node periodically shares its routing table with
_________ and whenever there is a change.
A) every other node
B) its immediate neighbors
C) one neighbor
21. The Routing Information Protocol (RIP) is an intradomain routing based on _________
routing.
A) distance vector
B) link state
C) path vector
22. The metric used by _______ is the hop count.
A) OSPF
B) RIP
C) BGP
23. In RIP, the ________ timer controls the advertising of regular update messages.
[2marks]
A) garbage collection

B) expiration
C) periodic
24. In RIP, the ________ timer is used to purge invalid routes from the table. [2marks]
B) expiration
C) periodic
25. In RIP, the ________ timer controls the validity of the route. [2marks]
B) expiration
C) periodic
26. RIP uses the services of _______.
A) TCP
B) UDP
C) IP
27. The _________ routing uses the Dijkstra algorithm to build a routing table.
A) distance vector
B) link state
C) path vector
28. The Open Shortest Path First (OSPF) protocol is an intradomain routing protocol
based on _______ routing.
A) distance vector
B) link state
C) path vector
29. The _______ protocol allows the administrator to assign a cost, called the metric, to
each route.
A) OSPF
B) RIP
C) BGP
30. In OSPF, a ________ link connects two routers without any other host or router in
between.
A) point-to-point
B) transient
C) stub

31. In OSPF, a _______ link is a network with several routers attached to it.
A) point-to-point
B) transient
C) stub
32. In OSPF, a ________ link is a network connected to only one router.
A) point-to-point
B) transient
C) stub
33. In OSPF, a ________ defines the links of a network.
A) network link
B) router link
C) summary link to network
34. ___________ is an interdomain routing protocol using path vector routing.
A) BGP
B) RIP
C) OSPF
35. A one-to-all communication between one source and all hosts on a network is
classified as a _______ communication.
A) unicast
B) multicast
C) broadcast
36. A one-to-many communication between one source and a specific group of hosts is
classified as a _______ communication.
A) unicast
B) multicast
C) broadcast
37. A one-to-one communication between one source and one destination is classified
as a _______ communication.
A) unicast
B) multicast
C) broadcast
38. In ______, the router forwards the received packet through only one of its interfaces.
A) unicasting
B) multicasting
C) broadcasting

39. In multicast routing, each involved router needs to construct a ________ path tree for
each group.
A) average
B) longest
C) shortest
40. In the _______ tree approach to multicasting, each router needs to create a separate
tree for each source-group.
A) group-shared
B) source-based
C) destination-based
41. The Multicast Open Shortest Path First (MOSPF) routing uses the _______ tree
approach.
A) source-based
B) group-shared
42. The Multicast Open Shortest Path First (MOSPF) protocol is an extension of the OSPF
protocol that uses multicast routing to create source-based trees. The protocol is based
on _______ routing. [2marks]
A) distance vector
B) link state
C) path vector
43. In RPF, a router forwards only the copy that has traveled the _______ path from the
source to the router.
A) shortest
B) longest
C) average
44. RPF eliminates the ________ in the flooding process.
A) forwarding
B) backwarding
C) flooding
45. RPB creates a shortest path _______ tree from the source to each destination.
A) unicast
B) multicast
C) broadcast

46. RPB guarantees that each destination receives _________ of the packet.
A) only one copy
B) no copies
C) multiple copies
47. In ________, the multicast packet must reach only those networks that have active
members for that particular group.
A) RPF
B) RPB
C) RPM
48. _______ adds pruning and grafting to _______ to create a multicast shortest path tree
that supports dynamic membership changes. [2marks]
A) RPM; RPB
B) RPB; RPM
C) RPF; RPM
49. __________ is an implementation of multicast distance vector routing. It is a source-
based routing protocol based on RIP. [2marks]
A) MOSPF
B) DVMRP
C) CBT
50. DVMRP is a ________routing protocol based on RIP.
A) source-based
B) group-shared
51. Pruning and grafting are strategies used in _______.
A) RPF
B) RPB
C) RPM
52. PIM-DM is used when the number of routers with attached members is ______
relative to the number of routers in the internet.
A) large
B) small
C) moderate
53. PIM-SM is used when the number of routers with attached members is ______ relative
to the number of routers in the internet. [2marks]

A) large
B) small
C) moderate
54. An OSPF router receives an LSA, the router checks its sequence number, and this
number matches the sequence number of the LSA that the receiving router already has.
What does the receiving router do with the LSA? [2marks]
A) Ignores the LSA
B) Adds it to the database
C) Sends newer LSU update to source router
D) Floods the LSA to the other routers
55. An OSPF router receives an LSA. The router checks its sequence number and finds
that this number is higher than the sequence number it already has. Which two tasks
does the router perform with the LSA? [2marks]
a) Ignores the LSA
b) Adds it to the database
c) Sends newer LSU update to source router
d) Floods the LSA to the other routers
56. Each LSA has its own age timer. By default, how long does an LSA wait before
requiring an update? [2marks]
a) 30 seconds
b) 1 minute
c) 30 minutes
d) 1 hour
57. Distance vector protocols use the concept of split horizon, but link-state routing
protocols, such as OSPF, do not.
a) True
b) False
58. The outcome of Dijkstra’s calculation is used to populate the __________
a) Topology table
b) Routing table
c) Neighbor table
d) Adjacency table
59. What is the IP protocol number for OSPF packets? [2marks]
a) 89
b) 86
c) 20
d) 76
60. Which multicast address does the OSPF Hello protocol use? [2marks]
a) 224.0.0.5
b) 224.0.0.6
c) 224.0.0.7

d) 224.0.0.8
61. The Hello protocol sends periodic updates to ensure that a neighbor relationship is
maintained between adjacent routers.
a) True
b) False
62. DBD packets are involved during which two states? [2marks]
a) Exstart and exchange
b) Loading and Two-way
c) Init and Full
d) Down and Loading
63. Which field is NOT a field within an OSPF packet header? [2marks]
a) Packet length
b) Router ID
c) Authentication type
d) Maxage time
64. In the IPv6 header, the traffic class field is similar to which field in the IPv4 header?
a) Fragmentation field
b) Fast-switching
c) ToS field
d) Option field
65. Which among the following features is present in IPv6 but not in IPv4? [2marks]
a) Fragmentation
b) Header checksum
c) Options
d) Anycast address
66. Dual-stack approach refers to _________ [2marks]
a) implementing Ipv4 with 2 stacks
b) implementing Ipv6 with 2 stacks
c) node has both IPv4 and IPv6 support
d) implementing a MAC address with 2 stacks
67. Suppose two IPv6 nodes want to interoperate using IPv6 datagrams, but they are
connected to each other by intervening IPv4 routers. The best solution here is ________
[2marks]
a) Use dual-stack approach
b) Tunneling
c) No solution
d) Replace the system
68. Which of these is not applicable for IP protocol?
a) Connectionless
b) Offer reliable service
c) Offer unreliable service

d) Does not offer error reporting
69. Which of the following demerits does Fragmentation have? [2marks]
a) Complicates routers
b) Open to DOS attack
c) Overlapping of fragments
d) All of the mentioned
70. Which field helps to check rearrangement of the fragments?
a) Offset
b) Flag
c) TTL
d) Identifier
71. In classless addressing, there are no classes but addresses are still granted in ______
a) IPs
b) Blocks
c) Codes
d) Sizes
72. In IPv4 Addresses, classful addressing is replaced with ________
a) Classless Addressing
b) Classful Addressing
c) Classful Advertising
d) Classless Advertising
73. First address in a block is used as network address that represents the ________
a) Class Network
b) Entity
c) Organization
d) Codes
74. In classful addressing, a large part of available addresses are ________
a) Organized
b) Blocked
c) Wasted
d) Communicated
75. Which of this is not a class of IP address?
a) Class E
b) Class C
c) Class D
d) Class F

UNIT – 4
TRANSPORT LAYER
1. One of the main duties of the transport layer is to provide ____________ communication.
A) node-to-node
B) host-to-host
C) process-to-process
2. A client program normally uses ____________ port number. A server program normally
uses __________ port number. [2marks]
A) a well-known; an ephemeral
B) an ephemeral; a well-known
C) a private; a well-known
3. A socket address is a combination of __________.
A) a MAC address and a logical address
B) a MAC address and a port number
C) a user-specific address and a logical address
4. ______________ means accepting items from more than one source. ______________ means
delivering items to more than one source. [2marks]
A) Demultiplexing; Multiplexing
B) Multiplexing; Demultiplexing
C) Encapsulation; Decapsulation
D) Pulling; Pushing
5. ________ means the producer delivers the items when they are produced. _______ means
the consumer takes the items when it is ready to do so. [2marks]
A) Pushing; Pulling
B) Pulling; Pushing
C) Forwarding; Accepting
6. In the stop-and-wait protocol, the maximum send window size is ______ and the
maximum receive window size is _______, where m is the number of bits in the sequence.
[2marks]
A) 1; 1
B) 2m; 1
C) 1; 2m
D) 2m; 2m
7. In the Go-Back-N protocol, the maximum send window size is ______ and the maximum
receive window size is _______, where m is related to the number of bits in the sequence
number. [2marks]
A) 1; 1

B) 1; 2m
C) 2m − 1; 1
D) 2m − 1; 2m − 1
8. In the selective-repeat protocol, the maximum send window size is ______ and the
maximum receive window size is _______, where m is the number of bits in the sequence.
[2marks]
A) 1; 1
B) 1; 2m − 1
C) 2m − 1; 1
D) 2m − 1; 2m – 1
9. UDP is a ________________transport protocol.
A) connectionless, reliable
B) connection-oriented, unreliable
C) connectionless, unreliable
10. UDP is an acronym for _______.
A) User Delivery Protocol
B) User Datagram Procedure
C) User Datagram Protocol
11. At the transport layer, to define the processes, we need two identifiers called
____________.
A) logical addresses
B) physical addresses
C) port addresses
12. The ports ranging from 0 to 1,023 are called the ___________ ports. The ports ranging
from 1,024 to 49,151 are called ___________ ports. The ports ranging from 49,152 to
65,535 are called the ___________ ports. [2marks]
A) well-known; registered; dynamic or private
B) registered; dynamic or private; well-known
C) private or dynamic; well-known; registered
D) private or dynamic; registered; well-known
13. UDP and TCP are two protocols at the ___________ layer.
A) data-link
B) network
C) transport
D) application
14. A port number is _______ bits long.
A) 8
B) 16
C) 32

D) 64
15. Communication at the transport layer is _________.
A) node-to-node
B) end-to-end
C) node-to-host
D) host-to-node
16. In Go-Back-N, the values of Sf = 3 and Sn = 7, after receiving a packet with ackNo = 6,
the value of Sf is _______________. [2marks]
A) 6
B) 7
C) 5
the value of Sn is _______________. [2marks]
A) 6
B) 7
C) 5
the window ________. [2marks]
A) slides two slots
B) slides one slot
C) slides three slots
D) does not slide
19. In Selective Repeat, the values of Sf = 3 and Sn = 7, after receiving a packet with
ackNo = 5, the window ________. [2marks]
A) slides two slots
B) slides one slot
C) slides three slots
D) does not slide
20. In Selective Repeat, when a timeout occurs, the timer is ________.
A) stopped
B) started
C) reset (stopped and started)
21. UDP and TCP are two protocols at the ___________ layer.
A) data-link
B) network
C) transport
D) application
22. A port number is _______ bits long.

A) 8
B) 16
C) 32
D) 64
23. Which of the following does UDP provide?
A) Flow control
B) Connection-oriented delivery
C) Error control
24. The source port number on the UDP user datagram header defines _______.
A) the sending computer
B) the receiving computer
C) the process running on the sending computer
25. To use the services of UDP, we need ________ socket addresses.
A) four
B) two
C) three
26. UDP packets are called __________.
A) user datagrams
B) segments
C) frames
27. UDP packets have a fixed-size header of _______ bytes.
A) 16
B) 8
C) 40
D) 32
28. TCP is a __________protocol.
A) byte-oriented
B) message-oriented
C) block-oriented
29. TCP groups a number of bytes together into a packet called a ___________.
A) user datagram
B) segment
C) datagram
30. TCP is a(n) ___________ protocol.
A) connection-oriented

B) connectionless
C) both connection-oriented and connectionless
31. TCP is a(n) _______ transport protocol.
A) unreliable
B) best-effort delivery
C) reliable
32. TCP uses _________________ to check the safe and sound arrival of data.
A) an acknowledgment mechanism
B) out-of-band signaling
C) the services of another protocol
33. The bytes of data being transferred in each connection are numbered by TCP. The
numbering starts with a __________________. [2marks]
A) 0
B) 1
C) randomly generated number
34. In TCP, the sequence number for each segment is the number of the _______ byte
(virtual byte) carried in that segment.
A) first
B) last
C) middle
35. Communication in TCP is ___________.
A) simplex
B) half-duplex
C) full-duplex
36. In TCP, the value of the acknowledgment field in a sent segment defines the
sequence number related to the ______byte a party expects to receive next.
A) first
B) last
C) next
37. The inclusion of the checksum in the TCP segment is ________.
A) optional
B) mandatory
C) depends on the type of data

38. In TCP, a SYN segment consumes _____ sequence number(s).
A) no
B) one
C) two
39. In TCP, a SYN + ACK segment consumes _____ sequence numbers.
A) no
B) three
C) two
D) one
40. In TCP, an ACK segment, if carrying no data, consumes ______ sequence number(s).
A) no
B) one
C) two
41. The connection establishment procedure in TCP is susceptible to a serious security
problem called the _________ attack.
A) ACK flooding
B) FIN flooding
C) SYN flooding
42. The SYN flooding attack belongs to a group of security attacks known as a _____
attack.
A) denial of service
B) replay
C) man-in-the middle
43. In TCP, a FIN segment consumes ____ sequence numbers if it does not carry data.
A) two
B) three
C) no
D) one
44. In TCP, a FIN + ACK segment consumes _____ sequence number(s) if it does not carry
data.
A) two
B) three
C) one
D) no
45. In TCP, one end can stop sending data while still receiving data. This is called a ______
termination.
A) half-close
B) half-open

C) full-close
46. TCP sliding windows are __________ oriented.
A) packet
B) segment
C) byte
47. In TCP, the size of the send window is the ________ of rwnd and cwnd.
A) maximum
B) sum of
C) minimum
48. In TCP, the window should not be _________.
A) opened
B) closed
C) shrunk
D) slide
49. In TCP, the receiver can temporarily shut down the window; the sender, however,
can always send a segment of _____ byte(s) after the window is shut down. [2marks]
A) ten
B) zero
C) one
50. A serious problem can arise in the sliding window operation when either the
sending application program creates data slowly or the receiving application program
consumes data slowly, or both. This problem is called the ______. [2marks]
A) silly window syndrome
B) unexpected syndrome
C) window bug
51. Nagle's algorithm can solve the silly window syndrome created by the _________.
A) sender
B) receiver
C) both sender and receiver
52. Clark's solution can solve the silly window syndrome created by the _________.
A) sender
B) receiver

53. Delayed acknowledgment can solve the silly window syndrome created by the
_________.
A) sender
B) receiver
54. In TCP, an ACK segments that carry no data consumes _______ sequence number(s).
A) no
B) one
C) two
55. In modern implementations of TCP, a retransmission occurs if the retransmission
timer expires or ________ duplicate ACK segments have arrived.
A) one
B) two
C) three
56. In TCP, ________ retransmission timer is set for an ACK segment.
A) one
B) a previous
C) no
57. In TCP, there can be ______ RTT measurement(s) in progress at any time.
A) two
B) only one
C) several
58. We need to multiply the header length field by _______ to find the total number of
bytes in the TCP header. [2marks]
A) 2
B) 4
C) 6
59. In TCP, urgent data requires the urgent pointer field as well as the URG bit (to be
set) in the _______ field. [2marks]
A) control
B) offset
C) sequence number
60. In TCP, if the ACK value is 200, then byte _______ has been received successfully.
[2marks]
A) 199

B) 200
C) 201
61. __________ control refers to the mechanisms and techniques to keep the load below
the capacity.
A) Flow
B) Error
C) Congestion
62. In TCP's ________ algorithm the size of the congestion window increases exponentially
until it reaches a threshold.
A) congestion avoidance
B) congestion detection
C) slow start
63. In TCP's __________ algorithm the size of the congestion window increases additively
until congestion is detected.
C) slow start
64. ________ treats the two signs of congestion detections, timeout and three duplicate
ACKs, in the same way. [2marks]
A) Taho TCP
B) Reno TCP
C) New Reno TCP
65. In ______ TCP, when the connection is established, TCP starts the slow start
algorithms and sets the ssthresh variable to a pre-agreed value (normally 64 or 128
kilobytes) and the cwnd variable to 1 MSS. [2marks]
A) Taho
B) Reno
C) new Reno
66. The ___________ added a new state to the congestion control FSM, called the fast
recovery state. [2marks]
A) Taho TCP
B) Reno TCP
C) new Reno TCP
67. The ___________ treated the two signals of congestion, timeout and arrival of three
duplicate ACKs, differently. [2marks]

A) Taho TCP
B) Reno TCP
C) new Reno TCP
68. The __________ state in Reno TCP is a state somehow between the slow start and the
congestion avoidance states.
C) slow recovery
69. In the Reno TCP, when TCP enters the fast recovery, if duplicate ACKs continue to
come, TCP ____________________________________. [2marks]
A) stays in this state, but the cwnd grows additively
B) stays in this state, but the cwnd grows exponentially
C) moves to slow start state
D) moves to the congestion avoidance state but deflate the size of the cwnd
to ssthresh value
70. In the Reno TCP, when TCP enters the fast recovery, if a timeout occurs, TCP
____________________________________. [2marks]
D) moves to the congestion avoidance state but deflate the size of the cwnd
to ssthresh value
71. In the Reno TCP, when TCP enters the fast recovery, if a new (non duplicate) ACK
arrives, TCP ____________________________________. [2marks]
D) moves to the congestion avoidance state but deflates the size of the cwnd
to ssthresh value
72. A later version of TCP, called ______ TCP, made an extra optimization on the _______
TCP. [2marks]
A) new Reno; Reno
B) new Taho; Taho
C) new Reno; Taho
D) new Taho; Reno
73. In the slow start algorithm, the size of the congestion window grows ______________
until ___________________. [2marks]
A) exponentially; it reaches a threshold
B) exponentially; congestion is detected
C) additively; it reaches a threshold
D) additively; congestion is detected

74. In the congestion avoidance algorithm, the size of the congestion window grows
______________. [2marks]
A) exponentially; it reaches a threshold
B) exponentially; congestion is detected
C) additively; it reaches a threshold
D) additively; congestion is detected
75. The congestion window size, after it passes the initial slow start state, follows a saw
tooth pattern called _________________________________. [2marks]
A) exponential increase, additive decrease
B) additive increase, exponential decrease
C) multiplicative increase, additive decrease
D) additive increase, multiplicative decrease
76. Stream Control Transmission Protocol (SCTP) is a new _____________protocol.
A) reliable, character-oriented
B) reliable, message-oriented
C) unreliable, message-oriented
77. SCTP allows __________ service in each association.
A) only single-stream
B) multistream
C) only double-stream
78. In SCTP, a data chunk is numbered using ________.
A) a TSN
B) an SI
C) an SSN
79. To distinguish between different streams, SCTP uses ___________.
A) a TSN
B) an SI
C) an SSN
80. The control information in SCTP is carried in the ________.
A) header control field
B) control chunks
C) data chunks
81. Which of the following is not a characteristic attributed to a data flow?
A) Reliability
B) Delay
C) Bandwidth

D) All choices are correct
82. Which of the following method is used to improve QoS?
A) Scheduling
B) Resource reservation
C) Traffic shaping or policing
83. Which of the following method is a scheduling technique?
A) FIFO queuing
B) Priority queuing
C) Weighted-fair queuing
84. A _______ algorithm is a policing technique that shapes bursty traffic into fixed-rate
traffic by averaging the data rate, but it does not give credit to the user during idle
periods.
A) leaky bucket
B) token bucket
C) priority queuing
D) weighted-fair queuing
85. A _______algorithm is a policing technique that allows bursty traffic at a regulated
maximum rate and give some credits to the user during idle periods.
A) leaky bucket
B) token bucket
C) priority queuing
D) weighted-fair queuing
86. Which QoS model depends heavily on resource reservation? [2marks]
A) IntServ
B) DiffServ
C) Scheduling
D) Policing
87. Integrated Services is a _______________ QoS model designed for IP.
A) flow-based
B) class-based
C) reliability-based
D) efficiency-based
88. Differentiated Services is a _______________ QoS model designed for IP.
A) flow-based
B) class-based
C) reliability-based
D) efficiency-based
89. Guaranteed services in IntServ model are required for __________application.
[2marks]

A) on-demand audio/video
B) stored audio/video
C) real-time
90. Controlled-Load services in IntServ model are designed for applications that
______________________. [2marks]
A) can accept some delays, but are sensitive to packet loss
B) can accept some packet loss, but are sensitive to delay
C) are sensitive to both delay and packet loss
D) are sensitive to neither delay nor packet loss
91. IntServ model is ________________________________________ [2marks]
A) scalable but has service type limitation.
B) scalable and does not have service type limitation.
C) not scalable and has service type limitation.
D) not scalable but does not have service type limitation.
92. To implement _________, the DS node uses _________________ such as meters, markers,
shapers, and droppers. [2marks]
A) Diffserv; traffic conditioners
B) Diffserv; gadgets
C) IntServ; traffic conditioners
D) IntServ; gadgets
93. FTP requires a _________ level of reliability.
A) low
B) medium
C) high
94. Voice over IP requires a _________ level of reliability.
A) low
B) medium
C) high
95. In priority queuing, when the higher-priority queue is full, the next packet is
_________.
A) sent to the lower priority queue
B) kept in the higher priority queue
C) discarded
96. In weighted-fair queuing, there is _________ starvation.
A) sometimes
B) never
C) always

97. In the leaky-bucket implementation, we use ____________.
A) FIFO queuing
B) priority queuing
C) weighted-fair queuing
98. In the token-bucket implementation, we use ____________.
A) FIFO queuing
B) priority queuing
C) weighted-fair queuing
99. Integrated Services use ____________ class(es) of service.
A) one
B) two
C) three
D) four.
100. Integrated Services use ____________ messages.
A) path
B) reservation
C) neither path nor reservation
D) both path and reservation
ANSWER KEY:

UNIT – 5
APPLICATION LAYER
1. HTTP uses the services of _________.
A) UDP
B) IP
C) TCP
D) DNS
2. In HTTP, the first line in a request message is called a _______ line; the first line in the
response message is called the ________ line. [2marks]
A) request; response
B) status; response
C) status; status
3. In a ___________ connection, one TCP connection is made for each request/response.
A) persistent
B) nonpersistent
C) persistent or a nonpersistent
4. In a ___________connection, the server leaves the connection open for more requests
after sending a response.
A) persistent
B) nonpersistent
C) persistent or nonpersistent
5. In HTTP, _______ server is a computer that keeps copies of responses to recent
requests.
A) a regular
B) a proxy
C) an auxiliary
D) a remote
6. An HTTP request message always contains _______. [2marks]
A) a header line and a body
B) a request line and a header line
C) a request line, a header line, and a body
D) a request line, a header line, a blank line, and a body
7. Which of the following is present in both an HTTP request line and a status line?
A) Version number
B) URL
C) Status code
D) Method

8. FTP uses the services of ________.
A) UDP
B) IP
C) TCP
9. In FTP, _________ well-known port(s) is (are) used.
A) one
B) two
C) three
D) four
10. During an FTP session the control connection is opened _______.
A) once
B) twice
C) many times
11. During an FTP session the data connection may be opened _______.
A) only once
B) only two times
C) as many times as needed
12. In FTP, a file can be organized into records, pages, or a stream of bytes. These are
types of an attribute called _______. [2marks]
A) file types
B) data structures
C) transmission modes
13. In FTP, there are three types of _______: stream, block, and compressed.
A) file types
B) data types
C) transmission modes
14. An FTP, ASCII, EBCDIC, and image define an attribute called _______.
A) file type
B) data structure
C) transmission mode
15. In FTP, when we _______, it is copied from the client to the server.
A) retrieve a file
B) store a file
C) open a file

16. In the common scenario, the electronic mail system needs _________________________.
[2marks]
A) two UAs, two MTAs, and one MAA
B) two UAs, two MTAs, and two MAAs
C) two UAs, two pairs of MTAs, and a pair of MAAs
D) two UAs, two pairs of MTAs, and two pairs of MAAs
17. ________ provides service to the user to make the process of sending or receiving a
message easier.
A) An MTA
B) An MAA
C) A UA
18. An e-mail message contains the ________ and the __________. [2marks]
A) header; envelop
B) header; body
C) envelop; body
19. In the Internet, an e-mail address consists of two parts: a _______ and a _______.
[2marks]
A) local part; domain name
B) global part; domain name
C) label; domain name
D) local part; label
20. _________ is a supplementary protocol that allows non-ASCII data to be sent through
e-mail. [2marks]
A) SMPT
B) MPEG
C) MIME
D) POP
21. The formal protocol that defines the MTA client and server in the Internet is called
___________. [2marks]
A) SMTP
B) SNMP
C) TELNET
D) SSH
22. SMTP is a __________protocol.
A) pull
B) push
C) push and pull
23. The message access protocol is a ________ protocol.
A) pull

B) push
C) push and pull
24. In the _______ encoding scheme, each 24 bits become four 6-bit chunks, and
eventually are sent as 32 bits. [2marks]
A) 8bit
B) binary
C) base64
D) quoted-printable
25. In the _______ encoding scheme, a non-ASCII character is sent as 3 characters.
A) 8bit
B) base64
C) quoted-printable
D) binary
26. TELNET is an abbreviation for ____________.
A) terminal network
B) telephone network
C) telecommunication network
27. When a user logs into a local time-sharing system, it is called ________ login.
A) local
B) remote
C) local or remote
28. When a user wants to access an application program or utility located on a remote
machine, he or she performs ___________ login.
A) local
B) remote
C) local or remote
29. Network Virtual Terminal (NVT) uses two sets of characters, one for _____and one for
__________. [2marks]
A) sending; receiving
B) request; reply
C) data; control
30. For data, NVT uses US ASCII characters with the highest order bit set to ______.
[2marks]
A) 1
B) 0
C) 1 or 0

31. For control, NVT uses US ASCII characters with the highest order bit set to ______.
[2marks]
A) 1
B) 0
C) 1 or 0
32. The _______ translates local characters into NVT characters. [2marks]
A) terminal driver
B) TELNET client
C) TELNET server
D) pseudoterminal driver
33. The _______ translates local characters into NVT characters. [2marks]
A) terminal driver
B) TELNET client
C) TELNET server
D) pseudoterminal driver
34. The _________ component in the SSH provides confidentiality, integrity,
authentication, and compression. [2marks]
A) SSH Application
B) SSH-AUTH
C) SSH-CONN
D) SSH-TRAN
35. Port forwarding is ____________________________. [2marks]
A) a protocol used to forward messages from one port to another port
B) a procedure for changing an ephemeral port to a well-known port
C) a service, provided by SSH, that creates a secure channel for applications
that do not have security services
36. In a (an) _______ name space, a name is a sequence of characters without structure.
A) linear
B) flat
C) hierarchical
D) organized
37. In a (an) _________name space, each name is made of several parts.
A) linear
B) flat
C) hierarchical
D) organized
38. In the DNS, the names are defined in ___________ structure.
A) a linear list
B) an inverted-tree

C) a three-dimensional
39. The root of the DNS tree is _______. [2marks]
A) a string of 127 characters
B) a string of 63 characters
C) a string of 15 characters
D) an empty string
40. In the domain name space, a full domain name is a sequence of labels separated by
________.
A) colons
B) semicolons
C) dots
D) commas
41. In the domain name space, if a label is terminated by a null string, it is called a
__________.
A) PQDN
B) CQDN
C) SQDN
42. In the domain name space, if a label is not terminated by a null string, it is called a
__________.
A) FQDN
B) PQDN
C) SQDN
43. In the domain name space, a _________ is a subtree of the domain name space.
A) label
B) name
C) domain
44. In the domain name space, what a server is responsible for or has authority over is
called a _________.
A) domain
B) label
C) zone
45. A _______ server is a computer whose zone system consists of the whole tree.
A) domain
B) zone
C) root
D) primary

46. A ________ server is a computer that stores a file about the zone for which it has an
authority.
A) primary
B) secondary
C) zone
D) root
47. A ________ server is a computer that transfers the complete information about a zone
from another server.
A) primary
B) secondary
C) zone
D) root
48. In the Internet, the country domain section uses ___________ country abbreviations.
A) two-character
B) three-character
C) four-character
49. In __________ resolution, the resolver expects the server to supply the final answer.
A) iterative
B) recursive
C) straight
50. In __________ resolution, the server returns the IP address of the server that it thinks
can resolve the query.
A) iterative
B) recursive
C) straight
51. DNS can use the services of ________.
A) UDP
B) TCP
C) either UDP or TCP
52. In a centralized P2P network, the directory system uses the ________paradigm; the
storing and downloading of the files are done using __________ paradigm. [2marks]
A) client-server; client-server
B) peer-to-peer; client-server
C) client-server; peer-to-peer
D) peer-to-peer; peer-to-peer.
53. Napster is an example of a ____________ peer-to-peer network.
A) centralized

B) structured-decentralized
C) unstructured-decentralized
54. Gnutella is an example of a ____________ peer-to-peer network. [2marks]
A) centralized
55. BitTorrent is an example of a ____________ peer-to-peer network. [2marks]
A) centralized
56. In a structured-decentralized P2P network ________________.
A) the directory system is kept in a center
B) a query to find a file must be flooded through the network
C) a pre-defined set of rules is used to link nodes so that a query can be
effectively and efficiently resolved
57. In a DHT-based network, each peer [2marks]
A) has a partial knowledge about the whole network.
B) has a complete knowledge about the whole network.
C) only has knowledge about its successor.
58. The finger table is the routing table used in ______________.
A) Gnutella
B) Pastry
C) Kademlia
59. Which of the following is not a Chord interface?
A) Lookup
B) Fix node
C) Stabilize
D) Join
60. In__________ a key is stored in a node whose identifier is numerically closest to the
key. [2marks]
A) Chord
B) Pastry
C) Kademlia

61. To resolve a query, _________ uses two entities: a routing table and a leaf set.
[2marks]
A) Chord
B) Pastry
C) Kademlia
62. In Kademlia, the distance between the two identifiers (nodes or keys) is measured
as the bitwise- ___________ between them.
A) AND
B) NOR
C) OR
63. In________, nodes and data items are m-bit identifiers that create an identifier space of
2m points distributed at the leaves of a binary tree.
A) Chord
B) Pastry
C) Kademlia
64. In Kademlia, each node in the network divides the binary tree into m subtrees
that___________.
A) include the node itself
B) do not include the node itself
C) include the node itself and the successor node
65. Trackerless BitTorrent uses __________ DHT to do the job of tracking. [2marks]
A) Chord
B) Pastry
C) Kademlia
66. Finger tables are used by __________.
A) Chord
B) Pastry
C) Kademlia
67. Three security goals are _______________________________________.
A) confidentiality, cryptography, and nonrepudiation
B) confidentiality, encryption, and decryption
C) confidentiality, integrity, and availability
68. Which of the following attacks is threatening integrity?
A) Masquerading
B) Traffic Analysis

C) Denial of service
69. Which of the following attacks is threatening availability?
A) Replaying
B) Modification
C) Denial of service
70. _____________ means concealing the contents of a message by enciphering.
A) Steganography
B) Cryptography
C) Compressing
71. ______________means concealing the message by covering it with something else.
A) Cryptography
B) Steganography
C) Compressing
72. In __________cryptography, the same key is used by the sender and the receiver.
A) symmetric-key
B) asymmetric-key
C) public-key
73. In _________ cryptography, the same key is used in both directions.
A) symmetric-key
B) asymmetric-key
C) public-key
74. _________ cryptography is often used for long messages.
A) Symmetric-key
B) Asymmetric-key
C) Public-key
75. ___________ cryptography is often used for short messages.
A) Symmetric-key
B) Asymmetric-key
C) Secret-key
76. __________means that the sender and the receiver expect confidentiality.
A) Nonrepudiation
B) Integrity
C) Authentication

77. ___________ means that the data must arrive at the receiver exactly as they were sent.
A) Nonrepudiation
B) Message integrity
C) Authentication
78. ______________ can provide authentication, integrity, and nonrepudiation for a
message.
A) Encryption/decryption
B) Digital signature
C) Compression
79. Digital signature does not provide _________.
A) nonrepudiation
B) privacy
C) authentication
D) Provides all of the choices
80. In ___________, the identity of a party is verified once for the entire duration of system
access.
A) entity authentication
B) message integrity
C) message authentication
81. In __________ cryptography, everyone has access to everyone's public key.
A) symmetric-key
B) asymmetric-key
C) secret-key
82. After a message is encrypted, it is called _______.
A) plaintext
B) ciphertext
C) cryptotext
83. In the asymmetric-key method used for confidentiality, which key is publicly
known?
A) Encryption key only
B) Decryption key only
C) Both keys
84. In the asymmetric-key method used for confidentiality, the receiver uses his/her
own ______________ to decrypt the message.

A) private key
B) public key
C) no key
85. The RSA algorithm for confidentiality uses _______ cryptography.
A) asymmetric-key
B) symmetric-key
C) substitution
86. In RSA, if user A wants to send an encrypted message to user B, the plaintext is
encrypted with the public key of _______.
A) user A
B) user B
C) the network
87. In the digital signature technique when the whole message is signed using an
asymmetric key, the sender of the message uses _______ to sign the message. [2marks]
A) his or her own symmetric key
B) his or her own private key
C) his or her own public key
88. In the digital signature technique when the whole message is signed using an
asymmetric key, the receiver of the message uses _______ to verify the signature.
[2marks]
A) her or his own public key
B) her or his own private key
C) the sender's public key
89. A _______ is a trusted third party that solves the problem of symmetric-key
distribution. [2marks]
A) CA
B) KDC
C) TLS
D) firewall
90. A _______ certifies the binding between a public key and its owner. [2marks]
A) CA
B) KDC
C) TLS

ANSWER KEY:
***KEEP LEARNING***HAPPY LEARNING***

Ec8551 communication networks mcq question bank

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