IP version 6, IPv6, is the new Internet Protocol for the world's growing multitude of mobiles, tablets, sensors, computers and routers. The Internet Protocol specifies the numerical addresses of devices on networks so they can locate each other and communicate.
The Internet Engineering Task Force designed the old IPv4 in 1981 to allow about 4.3 billion (4.3 x 109) addresses, which seemed a lot at the time. But as the Internet exploded in size and importance, the IETF realised this address limit was a looming disaster, and designed IPv6.
IPv6 increases this limit to a gigantic 340,282,366,920,938,000,000,000,000,000 billion (3.4 x 1038) addresses. It also provides better mobility, efficiency and security options.
Today the number of connected devices in the world far outstrips the available IPv4 addresses, so Internet and mobile access now depends on expensive stop-gap measures. Most global networks are already IPv6-capable, but many smaller enterprises and users still need to catch up in order to benefit from IPv6.
The two protocols, IPv6 and IPv4, have different formats so they are not backwardly compatible. An IPv4 address looks like 192.168.1.0, while an IPv6 address looks like 2001:db8:0:0:1234:0:0:1, because it is written in hexadecimal notation, which is easily understood by computers.
While is possible to run both protocols in the same network ('dual-stacking'), implementing IPv6 still requires careful planning ahead of time.