The first big test of the transition will come on June 8 2011, when the Internet Society sponsors World IPv6 Day. Major internet infrastructure operators, including Comcast, Time Warner Cable, Google, Microsoft, Yahoo!, Akamai, and Limelight will enable IPv6 on their systems for a 24-hour test run. As new sites appear on the internet they will only be accessible via IPv6 addresses as there will be no IPv4 addresses available.
You would think that 4,294,967,295 internet addresses was enough, well the answer to that is no. Less than 30 years after the Internet Protocol (IP) was adopted and almost 15 years after the internet went mainstream, the pool of numerical addresses that allow PCs, servers, mobile devices etc to find each other on the internet has been all but exhausted.
There is a solution to this, that will require a lot of background work but something the user will not notice. The internet and most networks currently use IPv4 the solution is to move to IP6. The big change is quadrupling the length of addresses to 128 bits, which provides many trillions of addresses for every person on earth. This year, the inevitable occurred and the Internet Assigned Numbers Authority, which is responsible for address assignments worldwide, announced it had given out the last unallocated blocks of IPv4 addresses. There are still lots of unused addresses around in scattered bits, but if you need a large block, it will have to be a IPv6 address.