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1 | |
In ________ we try to avoid traffic congestion. |
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| | A) | congestion control |
| | B) | quality of service |
| | C) | either (a) or (b) |
| | D) | both (a) and (b) |
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2 | |
In _________, we try to create an appropriate environment for the traffic. |
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| | A) | congestion control |
| | B) | quality of service |
| | C) | either (a) or (b) |
| | D) | both (a) and (b) |
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3 | |
Traffic ______ are qualitative values that represent a data flow. |
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| | A) | controls |
| | B) | descriptors |
| | C) | values |
| | D) | none of the above |
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4 | |
The _______ defines the maximum data rate of the traffic. |
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| | A) | peak data rate |
| | B) | maximum burst size |
| | C) | effective bandwidth |
| | D) | none of the above |
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5 | |
The________ normally refers to the maximum length of time the traffic is generated at the peak rate. |
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| | A) | peak data rate |
| | B) | maximum burst size |
| | C) | effective bandwidth |
| | D) | none of the above |
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6 | |
The ________ is a function of three values: average data rate, peak data rate, and maximum burst size. |
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| | A) | peak data rate |
| | B) | maximum burst size |
| | C) | effective bandwidth |
| | D) | none of the above |
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7 | |
A _________ traffic model has a data rate that does not change. |
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| | A) | constant bit rate |
| | B) | variable bit rate |
| | C) | bursty |
| | D) | none of the above |
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8 | |
In the ________ traffic model, the rate of the data flow changes in time, with the changes smooth instead of sudden and sharp. |
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| | A) | constant bit rate |
| | B) | variable bit rate |
| | C) | bursty |
| | D) | none of the above |
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9 | |
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 |
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10 | |
_______ happens in any system that involves waiting. |
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| | A) | Congestion |
| | B) | Jamming |
| | C) | Error |
| | D) | none of the above |
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11 | |
Congestion in a network or internetwork occurs because routers and switches have _______. |
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| | A) | tables |
| | B) | queues |
| | C) | crosspoints |
| | D) | none of the above |
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12 | |
In a network, when the load is much less than the capacity of the network, the delay is _________. |
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| | A) | at a maximum |
| | B) | at a minimum |
| | C) | constant |
| | D) | none of the above |
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13 | |
In a network, when the load reaches the network capacity, the delay _______. |
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| | A) | increases sharply |
| | B) | decreases sharply |
| | C) | remains constant |
| | D) | cannot be predicted |
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14 | |
In a network, when the load is below the capacity of the network, the throughput ______________. |
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| | A) | increases sharply |
| | B) | increases proportionally with the load |
| | C) | declines sharply |
| | D) | declines proportionally with the load |
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15 | |
In a network, after the load reaches the capacity, throughput _______. |
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| | A) | increases sharply |
| | B) | increases proportionally with the load |
| | C) | declines sharply |
| | D) | declines proportionally with the load |
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16 | |
In ________ congestion control, policies are applied to prevent congestion before it happens. |
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| | A) | open-loop |
| | B) | closed-loop |
| | C) | either (a) or (b) |
| | D) | neither (a) nor (b) |
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17 | |
In _______ congestion control, mechanisms are used to alleviate congestion after it happens. |
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| | A) | open-loop |
| | B) | closed-loop |
| | C) | either (a) or (b) |
| | D) | neither (a) nor (b) |
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18 | |
The technique of ________refers to a congestion control mechanism in which a congested node stops receiving data from the immediate upstream node or nodes. |
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| | A) | backpressure |
| | B) | choke packet |
| | C) | implicit signaling |
| | D) | explicit signaling |
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19 | |
A ___________ is a packet sent by a node to the source to inform it of congestion. |
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| | A) | backpressure |
| | B) | choke packet |
| | C) | implicit signaling |
| | D) | explicit signaling |
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20 | |
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. |
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| | A) | backpressure |
| | B) | choke packet |
| | C) | implicit signaling |
| | D) | explicit signaling |
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21 | |
In the __________ method, the signal is included in the packets that carry data. |
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| | A) | backpressure |
| | B) | choke packet |
| | C) | implicit signaling |
| | D) | explicit signaling |
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22 | |
In the ________ algorithm of TCP, the size of the congestion window increases exponentially until it reaches a threshold. |
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| | A) | slow-start |
| | B) | congestion avoidance |
| | C) | congestion detection |
| | D) | none of the above |
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23 | |
In the _________ algorithm of TCP, the size of the congestion window increases additively until congestion is detected. |
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| | A) | slow-start |
| | B) | congestion avoidance |
| | C) | congestion detection |
| | D) | none of the above |
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24 | |
In the ___________ algorithm of TCP, the size of the threshold is dropped to one-half, a multiplicative decrease. |
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| | A) | slow-start |
| | B) | congestion avoidance |
| | C) | congestion detection |
| | D) | none of the above |
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25 | |
In Frame Relay, the ________ bit warns the sender of congestion in the network. |
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| | A) | BECN |
| | B) | FECN |
| | C) | either (a) or (b) |
| | D) | neither (a) nor (b) |
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26 | |
In Frame Relay, the ________ bit is used to warn the receiver of congestion in the network. |
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| | A) | BECN |
| | B) | FECN |
| | C) | either (a) or (b) |
| | D) | neither (a) nor (b) |
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27 | |
Traditionally, ________types of characteristics are attributed to a flow. |
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| | A) | two |
| | B) | three |
| | C) | four |
| | D) | five |
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28 | |
_________ is a characteristic that a flow needs. Lack of it means losing a packet or acknowledgment, which entails retransmission. |
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| | A) | Reliability |
| | B) | Delay |
| | C) | Jitter |
| | D) | Bandwidth |
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29 | |
_______ is a flow characteristic that applications can tolerate in different degrees. |
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| | A) | Reliability |
| | B) | Delay |
| | C) | Jitter |
| | D) | Bandwidth |
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30 | |
________ is the variation in delay for packets belonging to the same flow. |
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| | A) | Reliability |
| | B) | Delay |
| | C) | Jitter |
| | D) | Bandwidth |
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31 | |
In ________, queuing packets wait in a buffer (queue) until the node (router or switch) is ready to process them. |
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| | A) | FIFO |
| | B) | priority |
| | C) | weighted fair |
| | D) | none of the above |
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32 | |
In ________ queuing, packets are first assigned to a priority class. Each class has its own queue. |
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| | A) | FIFO |
| | B) | priority |
| | C) | weighted fair |
| | D) | none of the above |
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33 | |
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. |
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| | A) | FIFO |
| | B) | priority |
| | C) | weighted fair |
| | D) | none of the above |
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34 | |
In the ______ bucket algorithm, bursty chunks are stored in the bucket and sent out at an average rate. |
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| | A) | leaky |
| | B) | token |
| | C) | either (a) or (b) |
| | D) | neither (a) nor (b) |
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35 | |
The _______ bucket algorithm allows idle hosts to accumulate credit for the future in the form of tokens. |
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| | A) | leaky |
| | B) | token |
| | C) | either (a) or (b) |
| | D) | neither (a) nor (b) |
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36 | |
In _________, when a source makes a reservation, it needs to define a flow specification. |
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| | A) | Integrated Services |
| | B) | Differentiated Services |
| | C) | Connectionless |
| | D) | Connection-Oriented |
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37 | |
_________ is a class-based QoS model designed for IP. |
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| | A) | Integrated Services |
| | B) | Differentiated Services |
| | C) | Connectionless |
| | D) | Connection-Oriented |
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38 | |
In Frame Relay, the user can never exceed the_________. |
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| | A) | access rate |
| | B) | committed burst size |
| | C) | committed information rate |
| | D) | excess burst size |
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39 | |
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. |
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| | A) | access rate |
| | B) | committed burst size |
| | C) | committed information rate |
| | D) | excess burst size |
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40 | |
In Frame Relay, the _____________ defines an average rate in bits per second. |
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| | A) | access rate |
| | B) | committed burst size |
| | C) | committed information rate |
| | D) | excess burst size |
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41 | |
In Frame Relay, the ___________ is the maximum number of bits in excess of Bc that a user can send during a predefined time. |
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| | A) | access rate |
| | B) | committed burst size |
| | C) | committed information rate |
| | D) | excess burst size |
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42 | |
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. |
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| | A) | CBR |
| | B) | VBR |
| | C) | ABR |
| | D) | UBR |
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43 | |
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. |
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| | A) | CBR |
| | B) | VBR |
| | C) | ABR |
| | D) | UBR |
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44 | |
In ATM, the _________ class delivers cells at a minimum rate. If more network capacity is available, this minimum rate can be exceeded. |
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| | A) | CBR |
| | B) | VBR |
| | C) | ABR |
| | D) | UBR |
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45 | |
In ATM, the _________ class is a best-effort delivery service that does not guarantee anything. |
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| | A) | CBR |
| | B) | VBR |
| | C) | ABR |
| | D) | UBR |