How many usable hosts are available in a subnet with a /28 prefix?

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Question: How many usable hosts are available in a subnet with a /28 prefix?

Options:

Correct Answer: 14

Solution:

A /28 subnet has 16 total addresses, but 2 are reserved (network and broadcast), leaving 14 usable host addresses.

How many usable hosts are available in a subnet with a /28 prefix?

How many usable hosts are available in a subnet with a /28 prefix?

Step 1: Understand what a /28 prefix means. A /28 prefix indicates that the first 28 bits of the IP address are used for the network part, and the remaining bits are used for host addresses.
Step 2: Calculate the total number of addresses in a /28 subnet. A /28 subnet has 32 - 28 = 4 bits left for host addresses. The total number of addresses is 2 raised to the power of the number of host bits: 2^4 = 16.
Step 3: Identify the reserved addresses. In every subnet, 1 address is reserved for the network address and 1 address is reserved for the broadcast address.
Step 4: Subtract the reserved addresses from the total addresses. So, 16 total addresses - 2 reserved addresses = 14 usable host addresses.

Subnetting – Understanding how to calculate the number of usable hosts in a subnet based on the CIDR notation.
CIDR Notation – Knowledge of how the prefix length (e.g., /28) affects the total number of addresses in a subnet.
Reserved Addresses – Recognizing that the first address is the network address and the last address is the broadcast address, which cannot be assigned to hosts.