Sub-netting & Super-netting


Sub-netting means dividing a huge network into small pieces of network.

Suppose we have a large block of IP address and it is purchased by some university, so a university does have a number of labs, so we can divide our block of IP’s into small small parts.

Here is an example of Subnetting.


Now let us understand it using the concept of IP addresses.Suppose the university has 64 pc’s and has 3 labs, lab 1 has 32 pc’s while lab 2 & lab 3 do gave 16 pc’s each.

Now assume that  the block of IP university has is As it has /26 which indicates that 2^6=64 pc’s are available.

Now we know that lab 1 has 32 pc’s.So block provided to that lab will be: to

Now here /27 has appeared because the new network has 32 pc’s equal to 2^5.

Also lab 2 & lab 3 have 16 pc’s each so in their IP addresses it will have /28.

Lab 2: to

Lab 3: to  

This is how subnetting is done in the institutes.


Super-netting means combining small networks to form a big network. A reverse process of subnetting is called supernetting.

Here is an example of Supernetting:

In supernetting the process is  just the reverse of subnetting and u need to adjust the mask using trial and error method.


1) In sub-netting the number of host decreases.

2) In super-netting it increases.



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