Since every IPv4 address has been assigned, engineers have been forced to utilize subnetting to extend the lifetime of the IPv4 addressing system.
Subnets take a network range and split it into subnetworks. When done properly this:
- Speeds the network up
- Allows for differing permissions per network
Subnetting requires an initial network address and a subnet mask. The subnet mask tells the system where the divide between the network address and device address is.
The first address is known as the Network Address. Immediately after that, the First Host Address is typically given to the subnet's router. The Broadcast Address is always the last address on the subnet. Therefore, the useable hosts will always be two less than the total hosts.