How is the number of hosts in a subnet calculated?

The calculation of the number of hosts in a subnet is based on the formula 2 raised to the power of the number of host bits minus 2. This formula arises from how IP addressing works in conjunction with subnetting. Each subnet has a certain number of bits dedicated to host addresses; the total number of addressable hosts in that subnet is represented by the power of 2 of those bits.

Specifically, the subtraction of 2 accounts for two special addresses that cannot be assigned to hosts: the subnet address, which identifies the subnet itself, and the broadcast address, which is used to communicate with all hosts on the subnet. Therefore, when determining the number of usable IP addresses for devices, the formula accurately reflects the allowable hosts by factoring in these reservations.

Understanding this formula is crucial for network design and management, as it helps ensure efficient use of IP addresses within your network architecture.