A relatively recent addition to the IP address architecture is CIDR. CIDR was born of the crisis that accompanied the Internet's explosive growth during the early 1990s.
As early as 1992, the IETF became concerned with the Internet's capability to continue to scale upward in response to demand for Internet use. Their specific concerns were as follows:
Exhaustion of the remaining, unassigned IPv4 network addresses. The Class B space was in particular danger of depletion.
The rapid, and substantial, increase in the size of the Internet's routing tables as a result of its growth.
All the indications were that the Internet's rapid growth would continue, as more commercial organizations came online. In fact, some members ...