Which class in traditional subnetting yields the largest default subnet mask, allowing the most hosts?

• A. Class B
• B. Class A
• C. Class C
• D. Class D

Answer: (B)

In traditional subnetting, the number of hosts per network is determined by how many bits are left for the host portion in the default subnet mask. Class A uses a default mask of 255.0.0.0, which leaves 24 bits for hosts. That allows up to 2^24 minus 2 usable addresses per network (16,777,214), which is far more than what Class B or Class C can offer. Class B has 16 host bits (65,534 usable hosts), and Class C has only 8 host bits (254 usable hosts). Class D is for multicast and isn’t used for regular host networks, so it doesn’t provide host addresses in the same sense. Therefore, Class A yields the most hosts.