In the previous tutorial, we have studied How to do subnetting. We studied how to divide the network into equal parts. Sometimes, we may need to divide a network into unequal parts and for that we need variable length subnet masking. In this tutorial, we will study about variable length subnet masking using an example.
– Assume we wish to divide a network into 3 parts such that –
Network ID – 18.104.22.168
1st part contains 128 addresses.
2nd part contains 64 addresses.
3rd part contains 64 addresses.
– We are dividing the network into 3 parts and thus we need at least 2 bits for subnet. But since the subnet is not divided into equal length addresses, we first divide the network into 2 equal parts, and then further divide one part into another two parts.
– Thus, the range of the divided network:
22.214.171.124 – 126.96.36.199
188.8.131.52 – 184.108.40.206
220.127.116.11 – 18.104.22.168
– Subnet Mask for Subnet 1: 255.255.255.128
– Subnet Mask for Subnet 2: 255.255.255.192
– Subnet Mask for Subnet 3: 255.255.255.192
– Subnet Mask is same for all subnets in fixed length subnet masking.
– Subnet Mask may be different for subnets in variable length subnet masking.
In the next tutorial, we will study about supernetting with example