See this question? If mask 255.255.255.128 were used with a Class B network, how many subnets could
exist, with how many hosts per subnet, respectively?
Answer: E. Class B networks imply 16 network bits, and the mask implies 7 host bits (7
binary 0s in the mask), leaving 9 subnet bits. 29 ? 2 yields 510 subnets, and 27 ? 2 yields
126 hosts per subnet
I would have said the answer is 512 subnets and 126 hosts.
Sometimes the rule is to minus 2 from the subnets?hence 510 and sometimes it?s not???.hence 512.
Do you know when you minus 2 from subnet?s and when you don?t??
Does it have something to do with if subnet zero is defined?