IPv6 Essentials, 2nd Edition

Chapter 1. Why IPv6?

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 ...