How many usable host IP addresses are on a network with a /28 CIDR subnet mask?

How many usable host IP addresses are on a network with a /28 CIDR subnet mask?

• A. 14
• B. 16
• C. 30
• D. 32

Answer: (A)

In a network with a /28 CIDR (Classless Inter-Domain Routing) subnet mask, the subnet mask indicates that the first 28 bits of the IP address are used for the network portion, leaving 4 bits for host addresses. To calculate the total number of addresses available for hosts, you use the formula \(2^n\), where \(n\) is the number of bits allocated for host addresses. In this case, with 4 bits available, you can calculate: \[ 2^4 = 16 \] This total of 16 includes all possible combinations of those 4 bits. However, in any subnet, two addresses are reserved: one for the network address (the address where all host bits are set to 0) and one for the broadcast address (the address where all host bits are set to 1). Consequently, to find the number of usable host IP addresses, you subtract these 2 reserved addresses from the total: \[ 16 - 2 = 14 \] Therefore, the correct number of usable host IP addresses in a /28 subnet is 14. This understanding is fundamental in network design, as it ensures that you're accounting for the reserved addresses while calculating

In a network with a /28 CIDR (Classless Inter-Domain Routing) subnet mask, the subnet mask indicates that the first 28 bits of the IP address are used for the network portion, leaving 4 bits for host addresses.

To calculate the total number of addresses available for hosts, you use the formula (2^n), where (n) is the number of bits allocated for host addresses. In this case, with 4 bits available, you can calculate:

[

2^4 = 16

]

This total of 16 includes all possible combinations of those 4 bits. However, in any subnet, two addresses are reserved: one for the network address (the address where all host bits are set to 0) and one for the broadcast address (the address where all host bits are set to 1).

Consequently, to find the number of usable host IP addresses, you subtract these 2 reserved addresses from the total:

[

16 - 2 = 14

]

Therefore, the correct number of usable host IP addresses in a /28 subnet is 14. This understanding is fundamental in network design, as it ensures that you're accounting for the reserved addresses while calculating