IPv6 is the web's solution to "the Internet is running out of addresses" dilemma that's been floating around for a few months.
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.
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.
Most users won't likely notice the test, says Google. The company estimates that around .05% of systems involved, especially home network equipment such as routers, may not revert to IPv4 after the tests. Affected users might find some of the aforementioned sites slow or unresponsive.
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. IPv4 and IPv6 run as parallel networks, so exchanging data between these protocols requires special gateways.