The IP version currently used in networks and the Internet is IP Version 4 (IPv4). IPv4 was developed in the early '70s to facilitate communication and information sharing between government researchers and academics in the United States. At the time, the system was closed with a limited number of access points, and consequently the developers didn't envision requirements such as security or quality of service. To its credit, IPv4 has survived for over 30 years and has been an integral part of the Internet revolution. But even the most cleverly designed systems age and eventually become obsolete. This is certainly the case for IPv4. Today's networking requirements extend far beyond support for web pages and email. Explosive growth in network device diversity and mobile communications, along with global adoption of networking technologies, are overwhelming IPv4 and have driven the development of a next-generation Internet Protocol.
IPv6 has been developed based on the rich experience we have from developing and using IPv4. Proven and established mechanisms have been retained, known limitations have been discarded, and scalability and flexibility have been extended. IPv6 is a protocol designed to handle the growth rate of the Internet and to cope with the demanding requirements on services, mobility, and end-to-end security.
When the Internet was switched from using Network Control Protocol (NCP) to Internet Protocol (IP) in one day in 1983, IP was not the mature protocol that we know today. Many of the well-known and commonly used extensions were developed in subsequent years to meet the growing requirements of the Internet. In comparison, hardware vendors and operating system providers have been supporting IPv6 since 1995 when it became a Draft Standard. In the decade since then, those implementations have matured, and IPv6 support has spread beyond the basic network infrastructure and will continue to be extended.
There is certainly a need for caution when considering adoption of IPv6there is still work to be done to reach parity with the maturity of IPv4 (refer to Chapter 10 for more details). The missing pieces of IPv6 will be developed in the coming years, just the way it happened with IPv4. And many enterprises are not finding enough reasons to adopt it right now. However, it is very important for organizations to pay attention to the introduction of IPv6 because its use is inevitable in the long term. If IPv6 is included in strategic planning; if organizations think about possible integration scenarios ahead of time; and if its introduction is considered when investing in IT capital expenditures, organizations can save considerable cost and can enable IPv6 more efficiently when it is needed.
An interesting and humorous overview of the history of the Internet can be found in RFC 2235, "Hobbes' Internet Timeline." The account starts in 1957 with the launch of Sputnik in Russia and the formation of the Advanced Research Projects Agency (ARPA) by the Department of Defense (DoD) in the United States. The RFC contains a list of yearly growth rate of hosts, networks, and domain registrations in the Internet.
Some excerpts from the RFC:
This is as far as the RFC goes. But history goes on. According to http://www.nua.ie/surveys/how_many_online/world.html, the worldwide online population reached 254 million users in 2000 and 580 million users in 2002. According to http://www.clickz.com/stats/web_worldwide, the online user population reached 1.08 billion users in 2005. In 2003, the U.S. Department of Defense (DoD) announced that they would be migrating the DoD network to IPv6 by 2008, and the Moonv6 (http://www.moonv6.com) project was started. In 2005, Google registered a /32 IPv6 prefix, and Vint Cerf, known as "Father of the Internet," joined Google. These are just a few selected events and milestones of the Internet's history. Keep watching as more history unfolds.