Like IPv4, IPv6 is also an internet-layer protocol for packet-switched internetworking that provides end-to-end datagram transmission across multiple IP networks. The currently used IPv4 allows 32 bits for an IP address, and therefore has an address space of 232 (4 294 967 296) possible addresses while IPv6 will use 128-bit addresses, for an address space of 2128 (approximately 3.4×1038) addresses. This expansion will allow many more devices and Internet users and an extra flexibility for allocating addresses and enhanced efficiency for routing traffic. Moreover, this will also eliminate the need for network address translation (NAT), which is a primary need at present.
However, the regular users may not find any difference due to this, as they will keep using the previous version IPv4 by default until their computers, the networks and the content and service providers gets ready for the use of IPv6.
However, according to the Internet Society, the Internet Service Providers (ISPs), home-networking equipment manufacturers and web companies will join the project as they have already undergone a test drive conducted on June 11, 2011, when many companies went the IPv6 way for a day.