MCQs in Congestion Control and Quality of Service

MCQs in Congestion Control and Quality of Service from the book Data Communications and Networking 4th Edition by Behrouz A. Forouzan. Reviewer in Electronics Systems and Technologies (Communications Engineering).

MCQs for Congestion Control and Quality of Service

This is the MCQs in Congestion Control and Quality of Service from book the Data Communications and Networking 4th Edition by Behrouz A. Forouzan. If you are looking for a reviewer in Electronics Systems and Technologies (Communications Engineering) this will definitely help you before taking the Board Exam.

Topic Outline

  • DATA TRAFFIC
  • CONGESTION
    • Open-Loop Congestion Control
    • Closed-Loop Congestion Control
  • TWO EXAMPLES
    • Congestion Control in TCP
    • Congestion Control in Frame Relay
  • QUALITY OF SERVICE
  • TECHNIQUES TO IMPROVE QoS
  • INTEGRATED SERVICES
  • DIFFERENTIATED SERVICES
  • QoS IN SWITCHED NETWORKS
    • QoS in Frame Relay
    • QoS in ATM

Begin and Good luck!

Choose the letter of the best answer in each questions.

1. _______ is a flow characteristic that applications can tolerate in different degrees.

  • A)            Reliability
  • B)            Delay
  • C)            Jitter
  • D)            Bandwidth

2. The _______ defines the maximum data rate of the traffic.

  • A)            peak data rate
  • B)            maximum burst size
  • C)            effective bandwidth
  • D)            none of the above

3. In Frame Relay, the _____________ defines an average rate in bits per second.

  • A)            access rate
  • B)            committed burst size
  • C)            committed information rate
  • D)            excess burst size

4. In ________ congestion control, policies are applied to prevent congestion before it happens.

  • A)            open-loop
  • B)            closed-loop
  • C)            either (a) or (b)
  • D)            neither (a) nor (b)

5. In ________ we try to avoid traffic congestion.

  • A)            congestion control
  • B)            quality of service
  • C)            either (a) or (b)
  • D)            both (a) and (b)

6. _________ is a characteristic that a flow needs. Lack of it means losing a packet or acknowledgment, which entails retransmission.

  • A)            Reliability
  • B)            Delay
  • C)            Jitter
  • D)            Bandwidth

7. In a network, after the load reaches the capacity, throughput _______.

  • A)            increases sharply
  • B)            increases proportionally with the load
  • C)            declines sharply
  • D)            declines proportionally with the load

8. In _________ queuing, the packets are assigned to different classes and admitted to different queues. The queues, however, are weighted based on the priority of the queues; higher priority means a higher weight. The system processes packets in each queue in a round-robin fashion with the number of packets selected from each queue based on the corresponding weight.

  • A)            FIFO
  • B)            priority
  • C)            weighted fair
  • D)            none of the above

9. In ATM, the _________ class is a best-effort delivery service that does not guarantee anything.

  • A)            CBR
  • B)            VBR
  • C)            ABR
  • D)           UBR

10. The________ normally refers to the maximum length of time the traffic is generated at the peak rate.

  • A)            peak data rate
  • B)            maximum burst size
  • C)            effective bandwidth
  • D)            none of the above

11. In _______ congestion control, mechanisms are used to alleviate congestion after it happens.

  • A)             open-loop
  • B)             closed-loop
  • C)             either (a) or (b)
  • D)             neither (a) nor (b)

12. _______ happens in any system that involves waiting.

  • A)             Congestion
  • B)             Jamming
  • C)             Error
  • D)             none of the above

13. In the ________ algorithm of TCP, the size of the congestion window increases exponentially until it reaches a threshold.

  • A)             slow-start
  • B)             congestion avoidance
  • C)             congestion detection
  • D)             none of the above

14. In Frame Relay, the user can never exceed the_________.

  • A)             access rate
  • B)             committed burst size
  • C)             committed information rate
  • D)             excess burst size

15. In the ___________ algorithm of TCP, the size of the threshold is dropped to one-half, a multiplicative decrease.

  • A)             slow-start
  • B)             congestion avoidance
  • C)             congestion detection
  • D)             none of the above

16. In _________, when a source makes a reservation, it needs to define a flow specification.

  • A)             Integrated Services
  • B)             Differentiated Services
  • C)             Connectionless
  • D)             Connection-Oriented

17. A _________ traffic model has a data rate that does not change.

  • A)             constant bit rate
  • B)             variable bit rate
  • C)             bursty
  • D)             none of the above

18. ________ is the variation in delay for packets belonging to the same flow.

  • A)             Reliability
  • B)             Delay
  • C)             Jitter
  • D)             Bandwidth

19. 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

20. In ATM, the _________ class delivers cells at a minimum rate. If more network capacity is available, this minimum rate can be exceeded.

  • A)             CBR
  • B)             VBR
  • C)             ABR
  • D)             UBR

21. In the ________ traffic model, the rate of the data flow changes in time, with the changes smooth instead of sudden and sharp.

  • A)             constant bit rate
  • B)             variable bit rate
  • C)             bursty
  • D)             none of the above

22. 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

23. In a network, when the load reaches the network capacity, the delay _______.

  • A)             increases sharply
  • B)             decreases sharply
  • C)             remains constant
  • D)             cannot be predicted

24. The technique of ________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

25. In ________ queuing, packets are first assigned to a priority class. Each class has its own queue.

  • A)             FIFO
  • B)             priority
  • C)             weighted fair
  • D)             none of the above

26. In ________, queuing packets wait in a buffer (queue) until the node (router or switch) is ready to process them.

  • A)             FIFO
  • B)             priority
  • C)             weighted fair
  • D)             none of the above

27. Traditionally, ________types of characteristics are attributed to a flow.

  • A)             two
  • B)             three
  • C)             four
  • D)             five

28. In Frame Relay, the ___________ is the maximum number of bits in excess of Bc that a user can send during a predefined time.

  • A)             access rate
  • B)             committed burst size
  • C)             committed information rate
  • D)             excess burst size

29. In a network, when the load is below the capacity of the network, the throughput ______________.

  • A)             increases sharply
  • B)             increases proportionally with the load
  • C)             declines sharply
  • D)             declines proportionally with the load

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

  • A)             backpressure
  • B)             choke packet
  • C)             implicit signaling
  • D)             explicit signaling

31. In a network, when the load is much less than the capacity of the network, the delay is _________.

  • A)             at a maximum
  • B)             at a minimum
  • C)             constant
  • D)             none of the above

32. Congestion in a network or internetwork occurs because routers and switches have _______.

  • A)             tables
  • B)             queues
  • C)             crosspoints
  • D)             none of the above

33. In _________, we try to create an appropriate environment for the traffic.

  • A)             congestion control
  • B)             quality of service
  • C)             either (a) or (b)
  • D)             both (a) and (b)

34. In Frame Relay, the ________ bit warns the sender of congestion in the network.

  • A)             BECN
  • B)             FECN
  • C)             either (a) or (b)
  • D)             neither (a) nor (b)

35. In Frame Relay, the ________ bit is used to warn the receiver of congestion in the network.

  • A)             BECN
  • B)             FECN
  • C)             either (a) or (b)
  • D)             neither (a) nor (b)

36. The ________ is a function of three values: average data rate, peak data rate, and maximum burst size.

  • A)             peak data rate
  • B)             maximum burst size
  • C)             effective bandwidth
  • D)             none of the above

37. In the _________ algorithm of TCP, the size of the congestion window increases additively until congestion is detected.

  • A)             slow-start
  • B)             congestion avoidance
  • C)             congestion detection
  • D)             none of the above

38. In ATM, the _________ class is divided into two subclasses: real-time (VBR-RT) and non-real-time (VBR-NRT). VBR-RT is designed for those users who need real-time services (such as voice and video transmission) and use compression techniques to create a variable bit rate. VBR-NRT is designed for those users who do not need real-time services but use compression techniques to create a variable bit rate.

  • A)             CBR
  • B)             VBR
  • C)             ABR
  • D)             UBR

39. Traffic ______ are qualitative values that represent a data flow.

  • A)             controls
  • B)             descriptors
  • C)             values
  • D)             none of the above

40. _________ is a class-based QoS model designed for IP.

  • A)             Integrated Services
  • B)             Differentiated Services
  • C)             Connectionless
  • D)             Connection-Oriented

41. In the ______ bucket algorithm, bursty chunks are stored in the bucket and sent out at an average rate.

  • A)             leaky
  • B)             token
  • C)             either (a) or (b)
  • D)             neither (a) nor (b)

42. The _______ bucket algorithm allows idle hosts to accumulate credit for the future in the form of tokens.

  • A)             leaky
  • B)             token
  • C)             either (a) or (b)
  • D)             neither (a) nor (b)

43. In ATM, the _________ class is designed for customers who need real-time audio or video services. The service is similar to that provided by a dedicated line such as a T line.

  • A)             CBR
  • B)             VBR
  • C)             ABR
  • D)             UBR

44. In the ______ traffic model, the data rate changes suddenly in a very short time.

  • A)             constant bit rate
  • B)             variable bit rate
  • C)             bursty
  • D)             none of the above

45. In Frame Relay, a ___________ is the maximum number of bits in a predefined time that the network is committed to transfer without discarding any frame or setting the DE bit.

  • A)             access rate
  • B)             committed burst size
  • C)             committed information rate
  • D)             excess burst size

Check your work.

Complete List of Chapter Quiz in Data Communications and Networking

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credit: Behrouz A. Forouzan© 2014 www.PinoyBIX.org

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