The number of possible addresses is 2^x. What does x represent?

• A. The number of bits the address uses
• B. The size of the subnet
• C. The number of networks
• D. The number of devices per network

Answer: (A)

The number of possible addresses grows as 2 raised to the power of how many bits are used in the address. That means x is the length of the address in bits. Each bit can be 0 or 1, so one bit gives 2 possibilities, two bits give 4, and with x bits you get 2^x possible addresses. For example, an 8-bit address has 256 possible addresses, while a 32-bit address (like IPv4) has 4,294,967,296 possibilities. The subnet size, number of networks, or devices per network depend on how those bits are divided between network and host parts, not on the total count of addresses alone.