An ISP has purchased address domain 200.100.0.0/20. If this ISP has 5 customers who want 120, 350, 68, 623 and 128 addresses, respectively. Answer the following qustions.

- Specify the address space required for each customer. Address space means determining the network mask along with determining the start and end address of each network.

- After assigning the address to these customers, how many free addresses are left to the ISP?

Tip: To determine the range of customer addresses, start with customers who want more addresses and then allocate address space to customers with fewer addresses.