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CCNA Practice Questions (Exam 640-802), Third Edition by Jeremy CCIE No. 11727 Cioara

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Answers and Explanations

  1. C. 172.16.0-3.0/22 breaks down into the following binary equivalents:

    172.16.0.0 = 10101100.00010000.00000000.00000000
    172.16.1.0 = 10101100.00010000.00000001.00000000
    172.16.2.0 = 10101100.00010000.00000010.00000000
    172.16.3.0 = 10101100.00010000.00000011.00000000

    Based on these binary values, you can see that the first 22 bits on each one of these IP addresses are the same. This makes the accurate summary address 172.16.0.0/22. All other answers are not valid.

  2. D. To find the valid number of hosts on a subnet, use the formula (2x) – 2, where “x” is the number of host bits in the subnet mask. A /21 (255.255.248.0) subnet mask has 11 host bits. (211) – 2 = 2046. All other answers are not valid.

  3. C, F. These styles of VLSM are ...

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