IPv4 has served the Internet well, but it was always limited in terms of its addressing capability, being able to support only 4 billion addresses. The boom in network and device (both fixed and mobile) growth has pushed the protocol to its limit and we are nearing address exhaustion.
So what happens when IPv4 runs out of space? Essentially it means that networks will lose the ability to grow (there are workarounds, but they are challenging and really only a short term bandage to the problem). IPv6 is designed to replace IPv4.
IPv6 addresses are 128 bits long (e.g. 2607:f0d0:4545:3:200:f8ff:fe21:67cf), compared to the 32 bit IPv4 addresses (e.g. 126.96.36.199). The end result is that IPv6 delivers a much larger address capacity than IPv4, supporting approximately 3.4 x 1038 addresses (or 8.5 x 1028 more addresses than IPv4 - big numbers).
Over a multi-year transition period, both IPv4 and IPv6 will be supported. IPv6 will eventually replace IPv4.
SoftLayer has provided native IPv6 support to our publicly available services since December 2008. SoftLayer does not have to worry about tunneling to carry IPv6 over IPv4 networks, which in turn means that our networks are not limited by the diminishing pool of IPv4 addresses. In addition, our support personnel are IPv6 savvy today.