What is IPv6?:
IPv6, short for Internet Protocol Version 6, is the next generation Internet Layer protocol that will be replacing the current version used today: IPv4. In Deccember 1998, IPv6 was designated as the successor to version 4 by the IETF, Internet Engineering Task Force.

The need for IPv6 was due to the exhaustion of IPv4 addressees. It is estimated that by 2011 most, if not all, of the IPv4 address will be in use (see counter on the left). IPv4 is still the protocol of choice for most of the Internet and thus the transition to IPv6 will be a steady one. One of the main features of IPv6 is that it allows for a significantly larger address space than IPv4. This is due to the fact that IPv6 addresses are 128-bits compared to IPv4 addresses which are 32-bits. Whereas IPv4 allows for a total of 2^12 addresses (~4.2 billion), IPv6 allows for a total of 2^128 addresses (~340 undecillion, the exact number is right below the My-IPv6.com Logo) -- that is approximately 2^95 addresses for each person alive in the world!!

Beside the larger address space there are other improvements in IPv6, such as: stateless address auto-configuration, mandatory Internet Protocol Security (IPsec), and simplified processing by routers.
www.my-ipv6.com