So far there have been two World IPv6 Days, and two of the five Regional Internet Registries (NICs) have reached IPv4 exhaustion, so everyone has deployed IPv6. Wait, they haven’t? Here’s why.
IPv6 isn’t Compatible
IPv4 is the primary protocol of the Internet. The Internet changed the way we interact with data, with the world around us, and with each other. It is a primary utility as real as water and power.
The primary problem with IPv6 is that it is not directly compatible with IPv4. Transition mechanisms are required to enable IPv6-IPv4 communication, adding an additional level of complication over the protocol transition It is a similar problem to adopting hydrogen-powered cars: people won’t buy them until there are refueling stations, and the stations won’t get built until enough people buy them. However, the problem is more complicated with IPv6: imagine if hydrogen-powered cars couldn’t use the same roads as gas-powered cars. “Transition mechanisms” would consist of car-hauling trucks or changing cars partway through the trip. Even if such mechanisms were automated, there would still be hesitation about adoption.