The Internet Engineering Task Force (IETF), which for all intents and purposes is the standards body of the Internet Protocol, has declared that "IPv6 is no longer considered optional." In RFC 6540 officially published late last week as an Internet Best Current Practice, the IETF cites the impending depletion of IPv4 address space with the continued growth of the Internet as drivers for widespread IPv6 deployment. While the RFC defines requirements for all developers of IP nodes, the main target seems to be consumer device vendors, many of whom have delayed implementation of IPv6. With consumers just implementing these IPv4-only devices today, they are likely to remain installed for many years, extending the IPv4 support lifecycle. Of course IPv4 will be around for quite some time, but the more of these devices that are IPv4+IPv6 instead of IPv4-only, the easier co-existence will be to manage.
Among the best practices recommended, the RFC stipulates that all new "IP implementations" must support IPv6, and IPv6 support must be equivalent to or better than corresponding IPv4 feature support and quality, that dual-stack support is required though IPv4 must not be required for operation, and existing hardware and software implementations should be considered for upgrade to IPv6 support.
Another interesting statement from the RFC is that "the term "IP" can now be interpreted to mean IPv4 + IPv6, IPv6-only, or IPv4-only." While separate standards exist for IPv4 and IPv6, the term "IP" now officially encompasses both protocols. Requirements for features specific to a given version should be so indicated, while general "IP" features will be assumed to apply to both.
This IETF statement complements what the Regional Internet Registries have been promoting for some time, and the World IPv6 Launch seven weeks away testifies to Internet heavyweights' participation in supporting IPv6 deployment. The IPAM Worldwide homepage features a graph embedded from the RIPE NCC which illustrates the relative density of IPv6 networks being advertised on the Internet. While the graph certainly shows a growing influence of IPv6, the raw numbers are also of interest. Considering the worldwide average, 5320 IPv6 networks are being advertised as of the end of March, 2012, while only 3594 were in March, 2011. This represents a 48% jump in advertised IPv6 networks. The industry momentum continues to build for IPv6!