This is supernetting tutorial. we will learn about supernetting definition, the need of supernetting and the rules followed to supernet a network. We will also look at an example of supernetting and the model questions possible.

In previous articles, we have studied about subnetting of fixed length Subnet mask and Subnetting of variable length mask . Subnetting and supernetting are opposite of each other. So, if you are not familiar with these terms, please visit the post first.

What is Supernetting?

– Joining two or more networks to form a larger network according to the requirements of user is known as supernetting.
– In case of a huge no of small networks, the size of routing table may increase exponentially, therefore, the router takes large time to process the routing table. Thus, to reduce the size of routing tables we require supernetting.
– Rules of supernetting:
      (i) All networks should be contiguous.
      (ii) Size of all the networks should be same and in the power of 2.
      (iii) First network ID should be divisible by total no. of networks.

Model Question 1:

In a class C network, if supernet mask is 255.255.252.0. Calculate the no. of networks that can be joined?

Supernetting Model Question

No. of networks that can be joined = $2^{Supernet Bits} = 4$

Note:
– During Supernetting, bits are borrowed from network portion.
– During Subnetting, bits are borrowed from the host portion.

Model Question 2:

If one of the address of supernet is 201.55.89.126. Supernet Mask is 255.255.252.0. Calculate the range of supernet.

Solutions –
As we already know, Supernet ID can be calculated by bitwise AND operation of IP address and Supernet Mask. So,
By AND operation of 201.55.89.126 and 255.255.252.0 –
201.55.89.126
255.255.252.0
= 201.55.88.0
So, range of the supernet is 201.55.88.0 – 201.55.91.255

That’s it about supernetting tutorial.

Now that we have studied everything about classful addressing, we will take a step ahead and study Classless Inter-domain routing in the next routing.
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