Objective 2.1

Plan a TCP/IP Network Infrastructure Strategy

15-11

C. Incorrect: The supplied address cannot provide users with Internet access using

a NAT router because the address is registered and NAT requires unregistered

addresses. Therefore, it is not true that the address satisfies the secondary goal.

The address does satisfy the primary goal, however, because the host identifier is

large enough to support up to 126 hosts.

D. Incorrect: Although the supplied address does not satisfy the secondary goal

because the address is registered, it does satisfy the primary goal.

4.

Correct Answers: A and D

A. Correct: This answer is correct because it is a Class A address with 14 network

identifier bits. Class A addresses have 8 network identifier bits, which leaves 6 bits

for the subnet identifier and 18 bits for the host identifier. The 6 bits are sufficient

to support 60 subnets, and each subnet can have up to 26,142 hosts.

B. Incorrect: This answer is incorrect because this is an unsubnetted Class C

address, which supports only one subnet with up to 254 hosts.

C. Incorrect: This answer is incorrect because, although a Class B address with 25

network identifier bits leaves 9 bits for the subnet identifier, which easily supports

60 subnets, only 7 bits are left for the host identifier. With only 7 bits for the host

identifier, you can only have up to 126 hosts on each subnet.

D. Correct: This answer is correct because a Class A address with 21 network iden-

tifier bits leaves 13 bits for the subnet identifier, which supports over 8,000 subnets

and over 2,000 hosts per subnet.