Question

A network administrator has the address block 10.0.0.0/22 and needs to create at least 6 equally-sized subnets. What subnet mask should be used, and how many usable host addresses will each resulting subnet support?

Q: Answer-A network administrator has the address block 10.0.0.0/22 and needs to create at least 6 equally-siz...

A 22 block has 3222 10 host bits available to redistribute. To create at least 6 subnets, we need to borrow enough bits so that 2borrowed bits 6 borrowing 3 bits gives 23 8 subnets enough, while borrowing only 2 bits gives just 22 4 subnets insufficient. Borrowing 3 bits moves the mask from 22 to 25 223. This leaves 3225 7 host bits per subnet, giving 27 2 126 usable host addresses per subnet subtracting 2 for the network and broadcast addresses.