In this article we understand what is CIDR (Classless Inter Domain Routing) in sub netting and Why we use it instead of class full addressing. Before understand the concept of CIDR let’s first understand why this technique is comes in sub netting means why we use in it. Why we use CIDR:- In now a day’s class full addressing is used. Which may be class A, B, C. These class full addressing are not sufficient because of now a days in world many small networks so the class C is used more. This is also called class C depletion ( …