Assuming the n= number of host bits, which of the following choices shows the correct formula for
finding maximum number of hosts per subnet?

A.
2n+2

B.
2n

C.
2n-2

D.
n+2

Explanation:
What the question is asking refers to the subnet mask. When it says number of host bits, it refers
to the number of bits in the subnet mask that represents the host. So, if I have a Class C address,
which gives me 24 bits for the network and 8 bits for the host, the question asks how many hosts

does the 8 bits give me. Well, two to the eighth power is 256. However, there are two special
situations where I can’t use addresses in the range. There are two special bit configurations for
broadcasts, the all zeros and the all ones broadcasts. This means that in the range of possible 256
addresses. I can’t use Zero or 255. So, I have to subtract 2, and that leaves me with 254 possible
host addresses.
Incorrect Answers:
A: This would be two many addresses, since I can never go over 2n, and even that is too many.
B: This is not enough, because there are two reserved addresses that cannot be used.
D: This is not correct, and actually doesn’t even come close.