What are the limitations of IPv4?
IPv4 is supposed to allow 232 (approximately four billion) addresses. The IPv4 scheme uses node addresses which are allocated from a 32-bit space. This 32-bit address space is further classified to provision Class A, B, and C ranges. And these ranges constitute network part of 8, 16, or 24-bit with corresponding host part of 24, 16, and 8-bit depending on the number of expected hosts on a network. This led to inefficient use of the 232 possible addresses. Many organizations automatically asked for Class A or B addresses and used up 224 or 216 addresses at each single assignment, even when they had a few host computers or many subnets with several computers on each. When two companies with Class A addresses merged, a lot of addresses were left unused and rarely re-claimed later. A network is designed to have a core, a distribution, and an access layer and we have to summarize at the different layers. There are chances that you cannot use addresses in a linear fashion. You have to divide
