subnetting

Question 1

How do you get the num of subnets available for a CIDR subnet?

Answer 1

2^x (x = number of borrowed bits)

Question 2

How do you calculate the size of a cidr subnet?

Answer 2

last network bit and add it to the address

ie (2^5 = 32 for /27, 192.168.255.0 -> 192.168.255.32)

Question 3

How do you calculate the number of available hosts?

Answer 3

2^n -2 (n=host bits)