We started hearing about IPv4 depletion in the mid-1990s, when distribution mechanisms and classful addressing made it a legitimate concern. Then the IETF did three significant things to ensure sustainable growth on the Internet:
- Classless Inter-Domain Routing (CIDR) – This allowed variable length subnet addressing, moving away from only three standard block sizes and making IP address space administration much more efficient. CIDR is one of the main reasons we still have IPv4 addresses available today.
- RFC 1918: Address Allocation for Private Internets – This RFC identified a set of IPv4 address space blocks for everyone to use on the private/internal side of their networks. These IP addresses are still commonly used across the world today. Without RFC 1918, the IPv4 address pool would have been depleted years ago.
- IPv6 – Knowing IPv4 would not satisfy the needs of a global commercial Internet, the IETF developed a new Internet Protocol that could satisfy the needs of a growing, global, commercial Internet.
CIDR and RFC 1918 were such great conservation measures that we still have available IPv4 address space to allocate today. Even so, the network has grown so large that billions of devices are now connected, steadily depleting IPv4 resources. At our current rate of global distribution, IPv4 will fully deplete sometime in the second half of 2011.
Now is the time to deploy IPv6, the newer numbering system that provides a much larger pool of IP addresses, amongst other features. Learn more in the Education Section, or dig down into the technical aspects of IPv6 on the IPv6 Wiki at www.getipv6.info.