Question 5 - Subnet mask and VLSM Flashcards
1
Q
Given the Class A network 10.0.0.0, create a subnet mask for the 600 subnets. Identify the 100th and VLSM for a further 25 subnets. Assume subnet 0 is used. Show all your working.
A
10 bits allows a maximum of 1024 subnets, so for 600 subnets the mask is 255.255.192.0 or /18.
The binary value for 99 (which is the 100th when you count from 0) has to be matched against the available bits.
Therefore the 100th is 10.24.192.0.
A further 25 subnets requires 5 extra bits, which is 255.255.254.0 or /23.
