The Internet Engineering Task Force, (IETF) specification for advising companies making the transition from IPv4 to IPv6 is the RTF 1933 specification. For transitioning, this document sets out these transition mechanisms:
When you upgrade your hosts and routers to IPv6, they retain their IPv4 functionality to provide compatibility for all IPv4 protocols and applications. These hosts and routers are known as dual stack.
They use the name service (for example, DNS) to carry information about which nodes are IPv6 capable.
IPv6 address formats can contain IPv4 addresses.
You can tunnel IPv6 packets in IPv4 packets as a means of crossing routers that have not been upgraded to IPv6.