Internet Protocol version 6 (IPv6) is the latest revision of the Internet Protocol (IP), the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet. IPv6 was developed to deal with the long-anticipated problem of IPv4 address exhaustion.
IPv6 is intended to replace IPv4, which still carries the vast majority of Internet traffic. Every device on the Internet must be assigned an IP address in order to communicate with other devices. With the ever-increasing number of new devices being connected to the Internet, the need arose for more addresses than IPv4 is able to accommodate. IPv6 uses a 128-bit address, whereas IPv4 uses 32-bit addresses. IPv4 allows only approximately 4.3 billion addresses whereas IPv6 provides Trillians and Trillians of addresses.
Since the two protocols are not designed to be interoperable, the transition to IPv6 will be a bit complicated and initially dual stack networks would exist to ensure the stability of the existing Internet on IPv4 and catering to the increased demand of more IP addresses through IPv6.