21. | Which one of the following statements is FALSE ? |
Discuss |
Answer: (b).Packet switching results in less variation in delay than circuit switching
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22. | Which of the following statements is TRUE about CSMA/CD ? |
Discuss |
Answer: (c).CSMA/CD is not suitable for a high propagation delay network like satellite network
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23. | Which of the following statements is FALSE regarding a bridge? |
Discuss |
Answer: (d).Bridge reduces broadcast domain
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24. | A network with CSMA/CD protocol in the MAC layer is running at 1 Gbps over a 1 km cable with no repeaters. The signal speed in the cable is 2 x 108 m/sec. The minimum frame size for this network should be |
Discuss |
Answer: (a).10000 bits
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25. | A channel has a bit rate of 4 kbps and one-way propagation delay of 20 ms. The channel uses stop and wait protocol. The transmission time of the acknowledgement frame is negligible. To get a channel efficiency of at least 50%, the minimum frame size should be |
Discuss |
Answer: (d).160 bits
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26. | In a TDM medium access control bus LAN, each station is assigned one time slot per cycle for transmission. Assume that the length of each time slot is the time to transmit 100 bits plus the end-to-end propagation delay. Assume a propagation speed of 2 x 10^8 m/sec. The length of the LAN is 1 km with a bandwidth of 10 Mbps. The maximum number of stations that can be allowed in the LAN so that the throughput of each station can be 2/3 Mbps is |
Discuss |
Answer: (c).10
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27. | Consider the following message M = 1010001101. The cyclic redundancy check (CRC) for this message using the divisor polynomial x^5 + x^4 + x^2 + 1 is : |
Discuss |
Answer: (a).01110
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28. | A sender uses the Stop-and-Wait ARQ protocol for reliable transmission of frames. Frames are of size 1000 bytes and the transmission rate at the sender is 80 Kbps (1Kbps = 1000 bits/second). Size of an acknowledgement is 100 bytes and the transmission rate at the receiver is 8 Kbps. The one-way propagation delay is 100 milliseconds. Assuming no frame is lost, the sender throughput is __________ bytes/second. |
Discuss |
Answer: (a).2500
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29. | In an Ethernet local area network, which one of the following statements is TRUE ? |
Discuss |
Answer: (d).The exponential backoff mechanism reduces the probability of collision on retransmissions
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30. | A network has a data transmission bandwidth of 20 × 10 6 bits per second. It uses CSMA/CD in the MAC layer. The maximum signal propagation time from one node to another node is 40 microseconds. The minimum size of a frame in the network is _________ bytes. |
Discuss |
Answer: (a).200
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