What are the necessary procedures in calculating subnet mask or simply subnetting?

To calculate a subnet mask, first determine the number of subnets or the number of hosts required, which will dictate how many bits you need to borrow from the host portion of the IP address. Convert the required number of bits into binary, then combine this with the default subnet mask for the IP class (Class A, B, or C). Finally, count the total number of bits used for the network (original bits plus borrowed bits) and convert this into the subnet mask format, typically expressed in CIDR notation (e.g., /24). Validate your calculation by ensuring the number of available subnets or hosts meets your requirements.