As IT-world celebrates IPv6 Day on Tuesday, Google, Facebook, Mozilla & Others Rev Up for IPv6 adoption. IPv6, the web solution to “the Internet is running out of addresses” dilemma. Allocation of the last extant blocks of IP addresses in February was a wakeup call for those who thought the net could keep growing as it is, forever.

The Internet has run out of Internet addresses… sort of.As the last blocks of IPv4 Internet addresses have already been allocated. IPv6 is the sixth revision to the Internet Protocol and the successor to IPv4. It functions similarly to IPv4 in that it provides the unique, numerical IP addresses necessary for Internet-enabled devices to communicate. However, it does sport one major difference: it utilizes 128-bit addresses. I’ll explain why this is important in a moment.Therefore, it can support 2^128 Internet addresses. That’s a lot of addresses, so many that it requires a hexadecimal system to display the addresses. In other words, there are more than enough IPv6 addresses to keep the Internet operational for a very, very long time. The solution for this problem — IPv6 — was first formalised in 1996, but patchy implementation and successful workarounds have kept it on the backburner.

In January, Google, the Internet Society, and several other web companies announced World IPv6 Day, when each organization would enable IPv6 addresses on their websites for a 24-hour period. Now, that list of organizations has grown to more than 400 tech companies, including Facebook, Mozilla, Bing, YouTube and many others. The depletion of IPv4 addresses was predicted years ago, so the switch has been in progress for the last decade. However, progress has been slow — only a small fraction of the web has switched over to the new protocol. In addition, IPv4 and IPv6 essentially run as parallel networks — exchanging data between these protocols requires special gateways. Where an IPv4 packet is primarily concerned with routing the data from one place to another, an IPv6 packet offers more space to detail how that data is to be delivered and secured. IPv6 addresses are split into two discrete elements: a 64-bit subnetwork prefix that indicates which network the device lives on, and a 64-bit identifier that identifies the specific interface to which the address points.

To make the switch, software and routers will have to be changed to support the more advanced network. This will take time and money. The first real test of the IPv6 network will come on World IPv6 Day. Google, Facebook and other prominent web companies will test drive the IPv6 network to see what it can handle and what still needs to be done to get the world switched over to the new network. At a global level, IPv6 day has the support of Google, Yahoo!, Facebook and Akamai, along with most networking vendors – Huawei, Ericsson, Tellabs, Qualcomm, F5, Bluecoat and RIM to name but a few.

Google said in a blog post that the global IPv6 test would go unnoticed by most of the world's internet users.

These companies’ services have been tweaked, upgraded and prepared for the IPv6 changes. The 24-hour test period will allow the above organizations to ensure bug-free IPv6 support. IPv6 is the sixth revision to the Internet Protocol and is the successor to IPv4. Both protocols provide the unique IP addresses necessary for Internet-connected devices to communicate. However, IPv6 utilizes 128-bit Internet addresses.