Refer to the exhibit. A network engineer has been given the network address of 192.168.99.0 and a subnet mask of 255.255.255.192 to subnet across the four networks shown. How many total host addresses are unused across all four subnets?

Refer to the exhibit. A network engineer has been given the network address of 192.168.99.0 and a subnet mask of 255.255.255.192 to subnet across the four networks shown. How many total host addresses are unused across all four subnets?

• 88
• 200
• 72
• 224
• 158

Explanation:

Usable hosts per subnet: A subnet mask of 255.255.255.192 (/26) leaves 6 host bits (32−26=6). Using the formula 2ⁿ−2, each subnet provides 62 usable host addresses (2⁶−2=62).

Used addresses: Across the four subnets, the total used addresses are 48 (30 for Network A, 14 for Network D, and 2 each for the router-to-router links in Networks B and C).

Total unused: With four subnets, there are 248 total usable addresses (62×4=248). Subtracting the 48 used addresses results in 200 unused host addresses (248−48=200).

Related exam: Introduction to Networks (Version 7.00) – Final Exam