The formula below maybe of use

_sub = n + log₂ (N/N_sub)

_sub The new subnet mask

n Original IP addresses block mask

N Total number of IP addresses available in an assigned block

_sub The number of addresses needed in a subnet

An organization is granted 175.17.10.0/20 block of addresses.

Find the total number of addresses in the block.

Translate the /20 mask into dotted decimal notation.

Find the FIRST and the LAST address in the assigned block (175.17.10.0/20).

Design the subnets as follows:

2 subnets with 100 addresses each

1 subnet with 64 addresses

Note: MUST list the first and the last address of each subnet with

the correct mask

e. How many addresses are NOT used from the assigned block

Please fill in the table below with your answer for sub-netting problem

Question	Answer
Total number of addresses
/20 mask in dotted-decimal
First and last addresses in assigned block	FA: LA:
4a. Subnet 1 first and last addresses with correct mask	FA: LA:
4b. Subnet 2 first and last addresses with correct mask	FA: LA:
4c. Subnet 3 first and last addresses with correct mask	FA: LA:
5.Number of addresses not used