Two portions of my Question:
As the internet grew, the original Classful addressing scheme became a limitation. The IP address space was being exhausted. (the question is how)
In case of classful addressing scheme, all networks had to choose one of three possible sizes, many addresses were unused (this sentence requires explanation)
What Is my point of view about this sentence, for example we have two networks using class c addressing scheme, in this case we can have 254 hosts , but we need to have only 12 hosts with our network. It means we only need 12 IP addresses, now in the second network we need to have 254 hosts, now we assign the IP addresses in sequence to these hosts (as the same suffix can be assigned to the computers on different networks because there network numbers are different so the IP addresses are unique).
Teacher says that if you need only 12 hosts in your network and you use class c Addressing scheme then you need only 4 bits in your suffix, but in case of class C you will assign the suffix portion to 12 computers and all the remaining possible IP addresses will be wasted. Question is what is the problem if they are wasted, I think they are not wasted we can use them in another network as I have described above.
Please note that i am a beginer not an expert like you people, therefore answer should be such that can be understood.