IPv4 (Internet Protocol version 4) has been the most widely used Internet Layer protocol since the inception of the Internet. This protocol uses 32-bit addresses to identify computing devices in a network. With 32-bits to use that means you can have 232, or 4,294,967,296 distinct addresses.
4.3 billion addresses in a world with 6.7 billion people doesn’t seem like nearly enough since everyone will eventually have their own desktop, netbook and handheld devices all of which will require an IP address. Consequently, the end result is that we will eventually run out of IPv4 addresses and civilization will grind to a halt.
Well, not exactly. The obvious solution to the IPv4 addressing scheme is to simply make the addresses larger. That’s where IPv6 comes in. IPv6 uses 128 bits for an address, 4 times as many bits as IPv4. Thanks to combinatorial math, however, it will make possible a substantially larger amount of addresses. To be exact 2128, or 3.4028236692093846346337460743177e+38 addresses in total.
BGPMon.net has a map showing IPv6 adoption worldwide. The U.S. is a laggard at only 3% while Japan is at 17% and Germany at 13% (Strangely enough, Cuba is the country with the highest adoption rate at 75%. BGPMon shows Jersey at 100% but I really don’t think Jersey is a country).
There are varying estimates for when IPv4 address exhaustion will occur, but the consensus is that this will happen sometime in 2010 to 2012. That doesn’t mean your IPv4 machine will stop working of course; it just means that if your company wants additional IPv4 addresses it won’t be able to get them. Many network devices and computers are already IPv6-capable but many are not. The transition will be interesting to watch. I plan to watch this more closely and I will share my findings here.