Facebook said Thursday that it was offering "experimental, non-production" support for IPv6, the long-anticipated upgrade to the Internet's main communications protocol.

The news about Facebook's IPv6 support was expected; Facebook told Network World in February, that it planned to support native IPv6 user requests "by the midpoint of this year."

In a presentation at the Google IPv6 Implementors Conference, Facebook's network engineers said it was "easy to make [the] site available on v6."

Facebook said it deployed dual-stack IPv4 and IPv6 support on its routers, and that it made no changes to its hosts in order to support IPv6.

Facebook also said it was supporting an emerging encapsulation mechanism known as Locator/ID Separation Protocol (LISP), which separates Internet addresses from endpoint identifiers to improve the scalability of IPv6 deployments.

"Facebook was the first major website on LISP (v4 and v6)," Facebook engineers said during their presentation. Facebook said that using LISP allowed them to deploy IPv6 services quickly with no extra cost.

Facebook's IPv6 services are available at www.v6.facebook.com, m.v6.facebook.com, www.lisp6.facebook.com and m.listp6.facebook.com.

Facebook is following in the footsteps of Google, Comcast, Netflix and other leading websites that are early adopters of IPv6

The Internet infrastructure is migrating to IPv6 because it is running out of address space using the current protocol, which is known as IPv4. The Regional Internet Registries said in April that only 8% of IPv4 address are unallocated. The remaining IPv4 addresses are expected to run out by 2012.

IPv4 uses 32-bit addresses and can support 4.3 billion devices connected directly to the Internet. IPv6, on the other hand, uses 128-bit addresses and supports a virtually unlimited number of devices – 2 to the 128th power.

John Curran, president and CEO of the American Registry for Internet Numbers (ARIN), has been urging Web site operators to deploy IPv6. Curran set a deadline of 1 January, 2012 when all public facing websites must support IPv6 or risk providing visitors with lower-grade connectivity.

Other popular websites that are known to be working on their IPv6 deployments include eBay, which plans production-quality IPv6 services in mid-2011, and the US federal government, which says that all components of its popular portal www.usa.gov are IPv6 capable.