CS8591 Computer Networks - UNIT IV TRANSPORT LAYER - - Multiple Choice Questions (MCQ)

 

CS8591 Computer Networks 

UNIT IV TRANSPORT LAYER

(Multiple Choice Questions (MCQ))

Introduction – Transport Layer Protocols – Services – Port Numbers – User Datagram Protocol – Transmission Control Protocol – SCTP.

 

1. Transport layer is the _________ layer in OSI layered architecture.

 A. First B. Second C. third D. fourth

Ans. D

2. The ______________ layer is responsible for the delivery of a message from one process to another. 

A. physical B. network C. transport D. data link

Ans. C

3. The __________ layer is lying between the network layer and session layer

A. physical B. network C. transport D. data link

Ans. C

4. The __________ layer gets the entire message to the correct process on the destination systems by adding a type of address called a service-point address (or port address).

A. physical B. network C. transport D. data link

Ans. C

5. Segmentation and reassembly are the functions (responsibilities) of _____________ layer.

A. physical B. network C. transport D. data link

Ans. C

6. Functions of Transport Layer are

A. End-to-end Delivery, Addressing

B. Reliable Delivery, Flow Control

C. Multiplexing

D. All of the above

Ans. D

7. Two basic types of transport services are

A. Connection services

B. Connectionless services

C. Both (a) and (b)

D. None of the above

Ans. C

8. Aspects related to the reliable delivery of the data are

A. Error control, Sequence control, Loss control, Duplication control

B. Error control, Sequence control, Loss control

C.  Sequence control, Loss control, Duplication control

D.  Error control, Sequence control, Duplication control

Ans. A

9. The _____________ layer oversees the end-to-end (source-to-destination) delivery of an entire message.

A. physical B. network C. transport D. data link

Ans. C

10. The _________ layer breaks messages into packets.

A. physical B. network C. transport D. data link

Ans. C

11. _________ layer performs error control if the lower layers are not adequately error free.

A. physical B. network C. transport D. data link

Ans. C

12. __________ layer performs flow control if flow control is not done adequately at the network layer.

A. physical B. network C. transport D. data link

Ans. C

13. Transport layer requires transport layer address called a ___________ for selecting multiple processes running on the destination host.

A. physical address

B. logical address

C. port number (port address)

D. none of the above

Ans. C

14. In the Internet model, the port numbers are ___ bits integers between 0 and 65,535.

A. 16 B. 32 C. 64 D. 128

Ans. A

15. The client program defines itself with a port number, chosen randomly by the transport layer software running on the client host. This is the _____ port number.

A. ephemeral

B. well-known

C. either (a) or (b)

D. none of the above

Ans. A

16. Server define a port number but not randomly. Internet has decided to use universal port numbers for servers, these are called __________ port numbers.

A. ephemeral

B. well-known

C. either (a) or (b)

D. none of the above

Ans. B

17. Well-known port numbers ranging from ________ are assigned and controlled by Internet Assigned Number Authority (IANA).

A. 0 to 1023

B. 1024 to 49151

C. 49152 to 65535

D. none of the above

Ans. A

18. Registered port numbers ranging from ________ are not assigned and controlled by IANA.(only registered to prevent duplication)

A. 0 to 1023

B. 1024 to 49151

C. 49152 to 65535

D. none of the above

Ans. B

19. Ephemeral port numbers (Dynamic port numbers) ranging from ______ are neither controlled nor registered. (used by any process)

A. 0 to 1023

B. 1024 to 49151

C. 49152 to 65535

D. none of the above

Ans. C

20. ________________ has Error Control, Sequence Control, Loss Control and Duplication Control.

A. Reliable delivery

B. unreliable delivery

C. either (a) or (b)

D. none of the above

Ans. A

21. In the transport layer, when transferring data, the primary goal of reliability is __________. Data must be delivered to their destination exactly as they originated from the source.

A. Error Control

B. Sequence Control

C. Loss Control and Duplication Control

D. all of the above

Ans. A

22. When the size of the data unit received from the upper layer is too long for the network layer datagram or data link frame to handle, the transport protocol divides it into smaller usable blocks called segments. This process is called ________.

A. Segmentation

B. Concatenation

C. both (a) and (b)

D. none of the above

Ans. A

23. When the size of the data units belonging to a single session are so small, the transport protocol can fit several data units together into a single datagram or frame. The combining process is called _____________.

A. Segmentation

B. Concatenation

C. both (a) and (b)

D. none of the above

Ans. B

24. In transport layer, some segments may be lost in transit, sequence numbers allow the receiver’s transport layer protocol to identify any missing segments and request redelivery. This is called ______________.

A. Error Control

B. Sequence Control

C. Loss Control

D. Duplication Control

Ans. C

25. The transport layer functions must guarantee that no piece of data arrive at the receiving system duplicated. This is called _____________.

A. Error Control

B. Sequence Control

C. Loss Control

D. Duplication Control

Ans. D

26. In transport layer, ____________ is a mechanism which controls overwhelming of data.

A. Error Control

B. Flow Control

C. Loss Control

D. Duplication Control

Ans. B

27.  ____________ is the process of combining multiple signals into one signal, over a shared medium.

A. Multiplexing

B. Demultiplexing

C. Synchronization

D. None of the above.

Ans. A

28.  ___________ a process reconverting a signal containing multiple analog or digital signal streams back into the original separate and unrelated signals.

A. Multiplexing

B. Demultiplexing

C. Synchronization

D. None of the above.

Ans. B

29. Basic techniques of multiplexing are:

A. Frequency Division Multiplexing

B. Time Division Multiplexing

C. Wave Division Multiplexing

D. All of the above

Ans. D

30. Which of the following is true about User Datagram Protocol (UDP)?

A. connectionless, unreliable TCP/IP transport layer protocol.

B. It provides process-to-to-process communication.

C. UDP has no error recovery procedures.

D. all of the above

Ans. D

31. Fields on which the UDP checksum is calculated are:

A. pseudoheader

B. UDP header

C. Data coming the application layer

D. All of the above

32. Applications of UDP are:

A. UDP is used for some route upding protocols such as RIP.

B. UDP is a convenient protocol for multimedia and multicasting applications.

C. It is suitable for a process with internal flow and error control mechanisms.

D. all of the above

33. UDP is preferred over TCP in the following applications

A. In multicasting

B. Route update protocol in RIP

C. both (a) and (b)

D. None of the above

Ans. C

34. Which of the following are true about Socket?

A. Socket is Communication end point.

B. It uses IP address and port number

C. both (a) and (b)

D. None of the above 

35. In ______, packets are called user datagrams.

A. UDP

B. TCP

C. IP

D. none of the above

Ans.A

36. Datagrams have fixed-size header of ___ bytes.

A.4 B.8 C.16 D.32

Ans. B

37. _______________________ runs over UDP and it is a network protocol for delivering audio and video over IP networks.

A. Real-time Transport Protocol (RTP)

B. TCP

C. IP

D. none of the above

Ans. A    

38. Both UDP and ______________________ are used in the transport layer.

A. Real-time Transport Protocol (RTP)

B. Transmission Control Protocol (TCP)

C. IP

D. none of the above

Ans. B    

39. TCP provides a _____________________________________.

A. connectionless, reliable, byte stream service

B. connection-oriented, unreliable, byte stream service

C. connection-oriented, reliable, byte stream service

D. none of the above

Ans. C

40. The Internet’s _______________________ is probably the most widely used protocol of this type.

A. Transmission Control Protocol (TCP)

B. User Datagram Protocol (UDP)

C. either (a) or (b)

D. none of the above

Ans. A

41. ______________ provides a reliable end-to-end byte stream delivery over an unreliable internetwork.

A. Transmission Control Protocol (TCP)

B. User Datagram Protocol (UDP)

C. either (a) or (b)

D. none of the above

Ans. A

42. TCP uses _________________________________________ mechanisms at the transport layer.

A. flow control and error control

B. flow control and access control

C. error control and access control

D. none of the above

Ans. A

43. TCP provides process-to-process communication using _________________.

A. logical addresses

B. physical addresses

C. port numbers

D. none of the above

Ans. C

44. ___________________ is a stream-oriented protocol.

A. User Datagram Protocol (UDP)

B. Transmission Control Protocol (TCP)

C. either (a) or (b)

D. none of the above

Ans. B

45. TCP groups a number of bytes together into a packet called __________.

A. Segment

B. data unit

C. either (a) or (b)

D. none of the above

Ans. A

46. A packet in TCP is called a _______________.

A. Segment

B. data unit

C. either (a) or (b)

D. none of the above

Ans. A

47. TCP Services include

A. Stream Delivery Service

B. Full-Duplex Communication

C. Connection-oriented Service & Reliable Service

D. all of the above

Ans. D

48. TCP allows the sending process to deliver data as a stream of bytes and the receiving process to receive data as a stream of bytes. This is _________________.

A. Stream Delivery Service

B. Full-Duplex Communication

C. Connection-oriented Service & Reliable Service

D. all of the above

Ans. A

49. TCP offers ________________, in which data can flow in both directions at the same time.

A. Stream Delivery Service

B. Full-Duplex Communication

C. Connection-oriented Service & Reliable Service

D. all of the above

Ans. B

50. TCP offers a _______________________, in which the two TCPs establish a connection between them, data are exchange in both directions, and the connection is terminated.

A. Stream Delivery Service

B. Full-Duplex Communication

C. Connection-oriented Service

D. Reliable Service

Ans. C

51. Transport layer creates the connection between source and destination. Events involved in the connection are:

A. Connection establishment

B. Data transfer

C. Connection release

D. All of the above

Ans. D

52. TCP provides a _________________ in which it uses an acknowledgment mechanism to check the safe and sound arrival of data.

A. Stream Delivery Service

B. Full-Duplex Communication

C. Connection-oriented Service

D. Reliable Service

Ans. D

53. The bytes of data being transferred in each connection are numbered by _____________. The numbering starts with a randomly generated number.

A. User Datagram Protocol (UDP)

B. Transmission Control Protocol (TCP)

C. either (a) or (b)

D. none of the above

Ans. B

54. Fields (expressed in bytes) in the numbering of bytes are

A. Sequence Number

B. Acknowledgment Number

C. both (a) and (b)

D. none of the above

Ans. C

55. After the bytes have been numbered, TCP assigns a sequence number to each segment that is being sent. The ______________ for each segment is the number of the first byte carried in that segment.

A. Sequence Number

B. Acknowledgment Number

C. both (a) and (b)

D. none of the above

Ans. A

56. TCP packets can contain an ________________ which is the sequence number of the next byte the sender expects to receive. The acknowledgement number is cumulative.

A. Sequence Number

B. Acknowledgment Number

C. both (a) and (b)

D. none of the above

Ans. B

57. Suppose a TCP connection is transferring a file of 5000 bytes. The first byte is numbered 10001. What is the sequence number for Segment 1 if data is sent in five segments, each carrying 1000 bytes?

A. 10,001

B. 11,001

C. 12,001

D. none of the above

58. In TCP, connection-oriented transmission require the following procedure(s).

A. Connection establishment

B. Connection termination

C. both (a) and (b)

D. either (a) or (b)

Ans. C

59. The algorithm used by TCP to establish and terminate a connection is called a __________________.

A. three-way handshake

B. two-way handshake

C. four-way handshake

D. none of the above

Ans. A

60. To keep track of all the different events happening during connection establishment, connection termination, and data transfer, TCP is specified as a _________.

A. Finite State Machine

B. Infinite State Machine

C. either (a) or (b)

D. none of the above

Ans. A

61. A connection progresses through a series of states during its lifetime. The diagram showing the transition of the these states is called ______________ .

A. State Transition Diagram

B. Finite State Machine

C. either (a) or (b)

D. none of the above

Ans. A

62. URG, ACK, PSH, RST, SYN and FIN are six flags in ___________ header

A. TCP

B. UDP

C. SCTP

D. None of the above

Ans. A

63. ___________ balances the rate a producer creates data with the rate a consumer can use the data.

A. flow control

B. error control

C. access control

D. none of the above

Ans. A

64. To accomplish flow control, TCP uses a ________________ protocol.

A. sliding window

B. silly window

C. either (a) or (b)

D. none of the above

65. A _______________ is used to make transmission more efficient as well as to control the flow of data so that the destination does not become overwhelmed with data.

A. silly window

B. sliding window

C. either (a) or (b)

D. none of the above

Ans. B

66. TCP’s variant of the sliding window algorithm serves the following.

A. It guarantees the reliable delivery of data,

B. It ensures that data is delivered in order, and

C. It enforces flow control between the sender and the receiver.

D. all of the above

Ans. D

67. A serious problem can arise in the sliding window operation when the receiver is only able to accept a few bytes at a time or when the sender transmits data in small segments repeatedly. This is called ____________ syndrome.

A. sliding window

B. silly window

C. either (a) or (b)

D. B

Ans. B

68. TCP guarantees the _______ delivery of data. So, it retransmits each segment if an ACK is not received in a certain period of time.

A. reliable

B. prompt

C. unreliable

D. none of the above

Ans. A

69. In retransmission, TCP sets the timeout as a function of the________________, it expects between the two ends of the connection.

A. Round Trip Time (RTT)

B. Time to Live (TTL)

C. either (a) or (b)

D. none of the above

Ans. A

70. ______________ is a measure of the time it takes for a packet to travel from a computer, across a network to another computer, and back.

A. Round Trip Time (RTT)

B. Time to Live (TTL)

C. either (a) or (b)

D. none of the above

Ans. A

71. To overcome the problem in calculating the RTT in today's world, TCP uses an ____________ retransmission mechanism.

A. adaptive

B. incremental

C. additive

D. multiplicative

Ans. A

72. Whenever TCP retransmits a segment, it stops taking sample of the RTT it only measures sample RTT for segments that have been sent only once. This solution is called ________________________________.

A. Karn / Partridge Algorithm

B. Jacobson / Karels Algorithm

C. either (a) or (b)

D. None of the above

Ans. A

73. In _______________________ algorithm, the sender measures a new sample RTT as before. It then folds this new sample into the timeout calculation. This algorithm is used by any end-to-end protocol.

A. Karn / Partridge

B. Jacobson / Karels

C. either (a) or (b)

D. None of the above

Ans. B

74. ____________ refers to techniques and mechanisms that can either prevent congestion, before it happens, or remove congestion, after it has happened.

A. Access Control

B. Congestion Control

C. Flow Control

D. Error control

Ans. B

75. Congestion control are of the following types:

A. Open-loop congestion control (prevention)

B. Closed-loop congestion control (removal)

C. both (a) and (b)

D. None of the above

Ans. C

76. In ____________ congestion control, policies are applied to prevent congestion before it happens.

A. open-loop

B. closed-loop

C. either (a) or (b)

D. None of the above

Ans. A

77. In _____________ control, mechanisms are used to alleviate congestion after it happens.

A. open-loop

B. closed-loop

C. either (a) or (b)

D. None of the above

Ans. B

78. _________________________ algorithm is a feedback control algorithm best known for its use in TCP congestion control.

A. Additive-Increase/Multiplicative-Decrease (AIMD)

B. Slow Start

C. either (a) or (b)

D. both (a) and (b)

Ans. A

79. In ________________________________, TCP maintains a new state variable for each connection, called Congestion Window, which is used by the source to limit how much data it is allowed to have in transit at a given time.

A. Additive-Increase/Multiplicative-Decrease

B. Slow Start

C. either (a) or (b)

D. both (a) and (b)

Ans. A

80. TCP provides a mechanism, called ___________, which is used to increase the congestion window rapidly from a cold start. Slow start effectively increases the congestion window exponentially, rather than linearly.

A. Additive-Increase/Multiplicative-Decrease (AIMD)

B. Slow Start

C. either (a) or (b)

D. both (a) and (b)

Ans. B

81. When too many packets are rushing to a node or part of network, the network performance degrades, and this situation is called as __________.

A. Collision

B. Congestion

C. trap

D. error

Ans. B

82. ____________ occurs because the switches in a network have a limited buffer size to store arrived packets before and after processing.

A. Congestion

B. Collision

C. Jamming

D. None of the above

Ans. A

83. The ways to handle congestion are:

A. Packet elimination

B. Flow control

C. Buffer allocation & Choke packets

D. All of the above

Ans. D

84. A ________________________ scheme allows a network to operate in the region of low delay and high throughput. It is a prevention mechanism.

A. Congestion control

B. Congestion avoidance

C. both (a) and (b)

D. None of the above

Ans. B

85. Congestion control is a ___________ whereas congestion avoidance is a _______________.

A. recovery mechanism, prevention mechanism.

B. prevention mechanism, recovery mechanism

C. either (a) or (b)

D. None of the above

Ans. A

86. The first mechanism ____________ was developed for use on the Digital Network Architecture (DNA), a connectionless network with a connection-oriented transport protocol. This technique is implemented in routers to avoid congestion.

A. DECBit

B. Random Early Detection (RED)

C. TCP Vegas

D. None of the above

Ans. A

87. When too many packets are rushing to a node or part of network, the network performance degrades, and this situation is called as __________.

A. Collision

B. Congestion

C. trap

D. error

Ans. B

88. A ________________________ scheme allows a network to operate in the region of low delay and high throughput. It is a prevention mechanism.

A. Congestion control

B. Congestion avoidance

C. both (a) and (b)

D. None of the above

Ans. B

89. Congestion control is a ___________ whereas congestion avoidance is a _______________.

A. recovery mechanism, prevention mechanism.

B. prevention mechanism, recovery mechanism

C. either (a) or (b)

D. None of the above

Ans. A

90. The first mechanism ____________ was developed for use on the Digital Network Architecture (DNA), a connectionless network with a connection-oriented transport protocol. This technique is implemented in routers to avoid congestion.

A. DECBit

B. Random Early Detection (RED)

C. TCP Vegas

D. None of the above

Ans. A

91. _____________ is a traffic shaping mechanism. In it, the input rate can vary but the output rate remains constant. A technique called leaky bucket can smooth out bursty traffic.

A. Leaky bucket

B. DECBit

C. RED

D. None of the above

Ans. A

92. The technique of back pressure refers to a congestion control mechanism in which a congested node stops receiving data from the immediate upstream node or nodes.

A. backpressure

B. choke packet

C. implicit signaling

D. explicit signaling

Ans. A

93. A ___________ is a packet sent by a node to the source to inform it of congestion.

A. backpressure

B. choke packet

C. implicit signaling

D. explicit signaling

Ans. B

94. In __________, there is no communication between the congested node or nodes and the source. The source guesses that there is a congestion somewhere in the network from other symptoms.

A. backpressure

B. choke packet

C. implicit signaling

D. explicit signaling

Ans. C

95. In the __________ method, the signal is included in the packets that carry data.

A. backpressure

B. choke packet

C. implicit signaling

D. explicit signaling

Ans. D     

96. Which of the following are true about Stream Control Transmission Protocol (SCTP)?

A. SCTP is a message-oriented,

B. reliable protocol that combines the best features of UDP and TCP

C. transport layer protocol

D. All of the above

Ans. D

97. SCTP allows __________ service in each association.

A. single stream

B. multistream

C. double stream

D. None of the above

Ans. B

98. SCTP association allows _____________ for each end.

A. only one IP address

B. multiple IP address

C. only two IP address

D. None of the above

Ans. B

99. In SCTP, a data chunk is numbered using ____________.

A. a Transmisson Sequencce Number (TSN)

B. an SI

C. an SSN

D. None of the above

Ans. A

100. To distinguish between different data chunks belonging to the same stream, SCTP uses _______________.

A. TSNs

B. SIs

C. Stream Sequence Numbers (SSNs)

D. None of the above

Ans. C

101. TCP has __________; SCTP has _______________

A. segment; packets

B. packets; segments

C. frames; segments

D. None of the above

Ans. A

102. The control information in SCTP is included in the ________.

A. header control field

B. data chunks

C. control chunks

D. none of the above

Ans. C

103. An SCTP packet can carry _______________.

A. no data chunks

B. only one data chunk

C. several data chunks

D. None of the above

Ans. C

104. In SCTP, the acknowledgment number and window size are part of each ________________.

A. Control chunk

B. data chunk

C. (a) or (b)

D. None of the above

Ans. A

105. There is no need for a header length field in SCTP because

A. the size of the header is fixed.

B. there are no options in the general header.

C. both (a) and (b)

D. none of the above

Ans. C

106. The checksum in SCTP is ___________ bits.

A. 8

B. 16

C. 32

D. 64

Ans. C

107. The association identifier in SCTP is _________________.

A. a combination of logical address and port address

B. a unique verification tag

C. either (a) or (b)

D. None of the above

Ans. B

108. In STP, control information and data information are carried in ________ chunks.

A. the same chunk

B. different chunks

C. either (a) or (b)

D. None of the above

Ans. B

109. In SCTP, acknowledgment numbers are used to acknowledge ______________.

A. only data chunks

B. only control chunks

C. both data chunks and control chunks

D. None of the above

Ans. A

110. In SCTP packet, control chunks come _________ data chunks.

A. before

B. after

C. either (a) or (b)

D. None of the above

Ans. A

111. In SCTP, ________________ can be carried in a packet that carries an INIT chunk.

A. no other chunk

B. only control chunks

C. only data chunks)

D. None of the above

Ans. A

112. A connection in SCTP is called an ___________________.

A. transmission

B. negotiation

C. association

D. None of the above

Ans. C

113. Which of the following is/are true about Quality of Service (QoS)?

A. Quality of Service (QoS) is a set of technologies that work on a network to guarantee its ability to dependably run high-.priority applications and traffic under limited network capacity.

B Measurements of concern to QoS are bandwidth (throughput), latency (delay), jitter (variance in latency), and error rate.

C. Both (a) and (b)

D. None of the above

Ans. C

114. The _____________________ defines a set of attributes related to the performance of the connection. For each connection, the user can request a particular attribute; each service class is associated with a set of attributes.

A. Quality of Service (QoS)

B. Stream service

C. None of the above

D. All of the above

Ans. A

115. The parameters/attributes of QoS are

A. Reliability

B. Bandwidth

C. Delay and Jitter

D. All of the above

Ans. D

116. The main goal of QoS is

A. to provide preferential treatment to an identified flow(s).

B. to increase delay

C. both (a) and (b)

D. None of the above

Ans. A

117. Main categories of QoS are

A. User-oriented

B. Network-oriented

C. both (a) and (b)

D. None of the above

Ans. C

118. Techniques used to improve QoS are

A. Scheduling, Traffic shaping, Admission control, Resource reservation

B. Scheduling, Traffic shaping, Admission control

C. Traffic shaping, Admission control, Resource reservation

D. Scheduling, Traffic shaping, Resource reservation

Ans. A

119. Which of the following are true about delay and jitter?

A. Delay is the time it takes a packet to travel across the network from source to destination.

B. Jitter is the fluctuation of end-to-end delay from packet to the next packet.

C. both (a) and (b)

D. None of the above

Ans. C

120. Packets from different flows arrive at a switch or router for processing. The routers and switches have queues (buffers) that hold the packets before and after processing. The scheduling method of processing the packets waiting in a queue is called _________________.

A. Waiting

B. Queuing

C. Flowing

D. None of the above

Ans. B      

121. Types of queuing are

A. First In First Out queuing

B. Priority queuing

C. Weighted fair queuing

D. All of the above

Ans. D

122. __________ on networks is an error-correction technique which can be used to correct data loss in packets sent over networks.  The way in which interleaving works can create latency issues (the time delay between data being sent and data being received).

A. intruding

B. interleaving

C. mixing

D. None of the above

Ans. B

123. One of more synchronization bits are usually added to the beginning of each frame. These bits are called ___________.

A. framing bits

B. DECbit

C. both (a) and (b)

D. None of the above

Ans. A

Dr. Selvaganesan
Dept of IT, JJCET