one problem with CLASSFUL ADDRESSING is that each class is divided into fixed number of blocks with each block having fixed size. A block in class A is too large for almost any organization . This means most of the addresses in class A were wasted and were not used .
A block in class B is also very large , probably too large for almost any organization and a class C block is too small for most midsize organizations.
To overcome this problem of address depletion and give more organizations access to the internet we go for classless addressing. :)
