Your network design calls for 17 subnets supporting 35 hosts

Your network design calls for 17 subnets supporting 35 hosts each. Your company provides the 135.72.0.0 address space. Which subnet mask would you create to satisfy the requirement?

A. 255.255.252.0

B. 255.255.254.0

C. 255.255.248.0

D. 255.255.240.0

Solution

Given address spce: 135.72.0.0

So, Subnet mask without subnetting: 255.255.0.0

Now, we need 17 subnet: means we need 5 bits from 3rd octet (32 subnet), we can not take 4 bits because it only cretes 16 subnet (subnet size is always in power of 2)

So, we have now, 135.72.11111000. 00000000

= 255. 255.248.0