B227 Data Communications
Quiz 2 2001
Directions
You are required to place you answers on a computer readable answer
sheet. Hand your completed sheet in at the end of the quiz.
Remember! Place your name and student No. on the answer sheet.
KEEP YOUR EYES ON YOUR OWN PAPER!!!
1.
Node-to-node delivery of the data unit is the responsibility of the
a) physical
b) data link
c) transport
d) network
2.
As the data packet moves from the lower to the upper layers, headers are
a) added
b) subtracted
c) rearranged
d) modified
3.
The
a)
b)
c)
d)
4.
Layer 2 lies between the physical layer and the
a) Network
b) data link
c) transport
d) presentation
5.
In the
layer, translations from one character code to another occur.
a) Transport
b) Session
c) Presentation
d) application
layer lies between the network layer and the session layer.
physical
data link
transport
presentation
6. What is the main function of the transport layer?
a) node-to-node delivery
b) end-to-end message delivery
c) synchronization
d) updating and maintenance of routing tables
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layer.
layer.
B227 Data Communications
Quiz 2 2001
7.
What is the major factor that makes coaxial cable less susceptible to noise than
twisted-pair cable?
a) inner conductor
b) diameter of cable
c) outer conductor
d) insulating material
8.
When making connections in fiber optics, which of the following could contribute
to signal distortion?
a) inner cores of connecting fibers angularly or laterally misaligned
b) a gap between connecting inner cores
c) roughness of connecting fiber faces
d) all of the above
9.
When a beam of light travels through media of two different densities, if the angle
of incidence is greater than the critical angle,
occurs.
a) reflection
b) refraction
c) incidence
d) criticism
10.
When we talk about unguided media, usually we are referring to
a) metallic wires
b) non-metallic wires
c) the atmosphere
d) none of the above
11.
The
has units of meters/second or kilometers/second.
a) throughput
b) propagation speed
c) propagation time
d) b or c
12.
a)
b)
c)
d)
13.
.
has units of bits/second.
Throughput
Propagation speed
Propagation time
b or c
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 travelled
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B227 Data Communications
Quiz 2 2001
14.
The wavelength of a signal depends on the
a) frequencies of the signal
b) medium
c) phase of the signal
d) a and b
15.
If odd parity is used for ASCII error detection, the number of 0s per eight-bit
symbol is
.
a) even
b) odd
c) indeterminate
d) 42
16.
.
In CRC there is no error if the remainder at the receiver is
a) equal to the remainder at the sender
b) zero
c) nonzero
d) the quotient at the sender
.
17.
In sliding window flow control, if the window size is 63, what is the range of
sequence numbers?
a) 0 to 63
b) 0 to 64
c) 1 to 63
d) 1 to 64
18.
In sliding window flow control, the frames to the left of the receiver window are
frames
.
a) received but not acknowledged
b) received and acknowledged
c) not received
d) not sent
19.
Regulation of the rate of transmission of data frames is known as
a) line discipline
b) flow control
c) data rate control
d) switch control
20.
The retransmission of damaged or lost frames in the data link layer is known as
a) error control
b) error conditioning
c) line discipline
d) flow control
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B227 Data Communications
Quiz 2 2001
21.
When a primary device wants to send data to a secondary device, it needs to first
send
frame.
a) an ACK
b) a poll
c) a SEL
d) an ENQ
22.
When a secondary device is ready to send data, it must wait for
a) an ACK
b) a poll
c) a SEL
d) an ENQ
frame.
23.
Flow control is needed to prevent
a) bit errors
b) overflow of the sender buffer
c) overflow of the receiver buffer
d) collision between sender and receiver
24.
In go-back-n ARQ, if frames 4, 5, and 6 are received successfully, the receiver
may send an ACK
to the sender.
a) 5
b) 6
c) 7
d) any of the above
25.
26.
27.
.
For a sliding window of size n - 1 (n sequence numbers), there can be a maximum
of
frames sent but unacknowledged.
a) 0
b) n - 1
c) n
d) n + 1
In
ARQ, when a NAK is received, all frames sent since the last frame
acknowledged are retransmitted.
a) stop-and-wait
b) go-back-n
c) selective-reject
d) a and b
ARQ stands for
.
a) automatic repeat quantization
b) automatic repeat request
c) automatic retransmission request
d) acknowledge repeat request
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B227 Data Communications
28.
Quiz 2 2001
Which of the following is a data link layer function?
a) line discipline
b) flow control
c) error control
d) all of the above
29. A timer is set when
a) a packet
b) an ACK
c) a NAK
d) all of the above
is sent out.
30. HDLC is an acronym for
.
a) high-duplex line communication
b) high-level data link control
c) half-duplex digital link combination
d) host double level circuit
31. The address field of a frame in HDLC protocol contains the address of the
a) primary
b) secondary
c) tertiary
d) a and b
32. HDLC is a
protocol.
a) character-oriented
b) bit-oriented
c) byte-oriented
d) count-oriented
33. The HDLC
a) fl ag
b) address
c) control
d) FCS
field defines the beginning and end of a frame.
34. What is present in all HDLC control fields?
a) P/F bit
b) N(R)
c) N(S)
d) code bits
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station.
B227 Data Communications
Quiz 2 2001
35. The shortest frame in HDLC protocol is usually the
a) information
b) supervisory
c) management
d) none of the above
frame.
36. When data and acknowledgment are sent on the same frame, this is called
a) piggybacking
b) backpacking
c) piggypacking
d) a good idea
37.
In CSMA/CD, the number of collisions is
a) greater than
b) less than
c) equal to
d) twice
that in MA.
38. In Ethernet, the source address field in the MAC frame is
a) the original sender's physical
b) the previous station's physical
c) the next destination's physical
d) the original sender's service port
39.
a)
b)
c)
d)
address.
uses a physical star topology.
10Base5
10Base2
10Base-T
none of the above
40. 10Base2 uses
cable, while 10Base5 uses
a) thick coaxial, thin coaxial
b) twisted-pair, thick coaxial
c) thin coaxial, thick coaxial
d) fiber-optic, thin coaxial
41. 10Base2 and 10Base5 have different
a) signal band types
b) fields on the 802.3 frame
c) maximum segment lengths
d) maximum data rates
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.
.
B227 Data Communications
42.
a)
b)
c)
d)
43. The
a)
b)
c)
d)
specifies a star topology featuring a central hub and daisy chaining.
10Base5
10Base2
10Base-T
10Base5
is a product of the LLC sublayer.
802.3 frame
802.5 frame
PDU
preamble
44. The monitor station in the
circulating.
a) 802.3
b) 802.5
c) FDDI
d) all of the above
45. The
a)
b)
c)
d)
Quiz 2 2001
standard ensures that only one token is
houses the switches in Token Ring.
NIC
MAU
nine-pin connector
transceiver
46. What can happen at a Token Ring station?
a) examination of the destination address
b) regeneration of the frame
c) passing of the frame to the next station
d) all of the above
47. In Token Ring, where is the token when a data frame is in circulation?
a) at the receiving station
b) at the sending station
c) circulating in the ring
d) none of the above
48. In Token Ring, when a frame reaches its destination station, which of the following
occurs?
a) The message is copied.
b) Four bits in the packet are changed.
c) The message is taken off the ring and replaced by the token.
d) a and b
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B227 Data Communications
49.
Quiz 2 2001
Which of the following frame types is specified in the 802.5 standard?
a) token
b) abort
c) data/command
d) all of the above
50.
Which Project 802 standard provides for a collision-free protocol?
a) 802.2
b) 802.3
c) 802.5
d) 802.6
51.
Which LAN has the highest data rate?
a) 10Base5
b) 10Base-T
c) twisted-pair Token Ring
d) FDDI
52.
Another term for CSMA/CD and the IEEE 802.3 standard is
a) Ethemet
b) Token Ring
c) FDDI
d) Token Bus
53. IEEE Project 802 divides the data link layer into an upper.
lower
sublayer.
a) LLC, MAC
b) MAC, LLC
c) C.PDU,HDLC
d) HDLC, PDU
54. FDDI is an acronym for
.
a) fast data delivery interface
b) fiber distributed data interface
c) fiber distributed digital interface
d) fast distributed data interface
55. In FDDI, data normally travel on
a) the primary ring
b) the secondary ring
c) both rings
d) neither ring
.
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sublayer and a
B227 Data Communications
Quiz 2 2001
56. What is the main purpose of the secondary ring in FDDI protocol?
a) If the primary ring fails, the secondary takes over.
b) If the primary ring fails, the primary makes a wrap connection with the
secondary to heal the ring.
c) The secondary alternates with the primary in transmission of data.
d) The secondary is used to send emergency messages when the primary is busy.
57. In which OSI layers does the FDDI protocol operate?
a) physical
b) data link
c) network
d) a and b
58. In
a)
b)
c)
d)
a frame goes to just one destination instead of all stations.
traditional Ethernet
Switched Ethernet
Token Ring
a and b
59. In
a)
b)
c)
d)
a frame goes to all stations.
traditional Ethernet
Switched Ethernet
Token Ring
a and b
60.
The collision domain is the
a) minimum
b) maximum
c) virtual
d) a and b
distance data travels between two stations.
61. The collision domain of traditional Ethernet is
domain of Fast Ethernet is
meters.
a) 250; 250
b) 250; 2500
c) 2500;250
d) 2500;2500
62.
In an Ethernet network, if the round-trip time
a) increases; decreases
b) decreases; decreases
c) decreases; increases
d) none of the above
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meters; the collision
, the collision domain
.
B227 Data Communications
Quiz 2 2001
63. 100Base-X differs from 100Base-T4 in
.
a) the data transmission rate
b) topology
c) the frame format
d) the number of cables between the station and the hub
64. The station-to-hub distance in
is 2000 meters.
a) 100Base-TX
b) 100Base-FX
c) 100Base-T4
d) 100Base-T1
65. Gigabit Ethernet has a
data rate than Fast Ethernet and a
domain.
a) higher; higher
b) higher; lower
c) lower; lower
d) lower; higher
66. Which type of switching uses the entire capacity of a dedicated link?
a) circuit switching
b) datagram packet switching
c) virtual circuit packet switching
d) message switching
67. A switched virtual circuit involves
a) connection establishment
b) data transfer
c) connection release
d) all of the above
.
68. Apermanent virtual circuit involves
a) connection establishment
b) data transfer
c) connection release
d) all of the above
.
69. Which of the following is true about the IP address?
a) It's divided into exactly two classes.
b) It contains a fixed-length hostid.
c) It was established as a user-friendly interface.
d) It is 32 bits long.
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collision
B227 Data Communications
Quiz 2 2001
70. Which IP address class has few hosts per network?
a) A
b) B
c) C
d) D
71. For what does the data link layer look for as it sends a frame from one link to
another?
a) hostid
b) IP address
c) domain name
d) station address
72.
The purpose of ARP on a network is to find the
a) Internet address, domain name
b) Internet address, netid
c) Intemet address, station address
d) station address, Intemet address
73.
Which of the following apply to UDP?
a) is unreliable and connectionless
b) contains destination and source port addresses
c) reports certain errors
d) all of the above
74.
Which of the following applies(y) to both UDP and TCP?
a) transport layer protocols
b) port-to-port communication
c) services of IP layer used
d) all of the above
75. Which of the following is a class A host address?
a) 128.4.5.6
b) 117.4.5.1
c) 117.0.0.0
d) 117.8.0.0
76.
Which of the following is a class B host address?
a) 230.0.0.0
b) 130.4.5.6
c) 230.0.0.0
d) 30.4.5.6
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given the
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B227 Data Communications
Quiz 2 2001
77. Which of the following is a class C host address?
a) 230.0.0.0
b) 130.4.5.6
c) 200.1.2.3
d) 30.4.1.6
78.
The data unit in the TCP/IP application layer is called a
a) message
b) segment
c) datagram
d) frame
.
79.
When a host knows its physical address but not its IP address, it can use
a) ICMP
b) IGMP
c) ARP
d) RARP
80. Which of the following is the default mask for the address 198.0.46.201?
a) 255.0.0.0
b) 255.255.0.0
c) 255.255.255.0
d) 255.255.255.255
End of Quiz
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