IPv6 is the long-anticipated upgrade to the Internet's main communications protocol, which is known as IPv4.
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.
Here are the basics you need to know to get your network ready to support both IPv6 and IPv4.
The Internet Engineering Task Force (IETF), a standards body, created IPv6 as a replacement to IPv4 in 1998, when it became clear that the Internet would eventually run out of IPv4 addresses.
IPv6's primary goal is to increase the Internet's address space, but the protocol also has some enhancements, including autoconfiguration, easier network renumbering and built-in security through the IPsec protocol.
IPv6 has been slow to gain adoption, but momentum began picking up in 2009. Hurricane Electric and NTT America said their IPv6 traffic doubled in 2009, while Google added IPv6 support to several applications including Search, Docs, Gmail and News.
The push towards IPv6 has continued in 2010, with Comcast and Verizon announcing their first public trials of the protocol.
The U.S. federal government is a proponent of IPv6, setting a mandate of June 2008 for all agencies to demonstrate that their backbone networks are capable of carrying IPv6 traffic. After July 2010, the Federal Acquisition Regulation will be changed to require agencies to purchase only IPv6-capable IT systems.
Experts are urging U.S. network managers to prepare their external facing Web sites to support IPv6 by 2012 or risk upsetting IPv6-enabled visitors with lower-grade connectivity.
As of March 2010, experts said that IPv6 had grown to represent 1% of all Internet traffic.
IPv4 Address Exhaustion
IPv4 address exhaustion has been a concern since the 1980s, when Internet engineers came up with several techniques that would allow the Internet to continue growing while a replacement to IPv4 was developed.
These techniques include network address translation (NAT), which allows organizations to hide private network addresses behind a single public IPv4 address, and Classless Inter-Domain Routing (CIDR), a more scalable way of allocating and routing IP address blocks. CIDR and NAT worked, which allowed the Internet engineering community to delay upgrading the Internet infrastructure from IPv4 to IPv6.
Now, however, the upgrade to IPv6 is looming for carriers and enterprises. The regional Internet registries said in April 2010 that less than 8% of IPv4 addresses remain unallocated.
Experts predict that IPv4 address space will run out in 2011 or 2012.
IPv6 Transition Mechanisms
The Internet engineering community has developed several transition mechanisms that will allow network operators to gradually migrate from IPv4 to IPv6.
One option, called Dual Stack, allows network operators to run IPv4 and IPv6 side-by-side on their networks.
Another option is carrier-grade NAT that would allow multiple customers to share a single, public IPv4 address.
A third option, called 6rd, was used by the French ISP Free to rapidly deploy IPv6 to its residential customers by encapsulating IPv6 packets for transmission over IPv4 backbone networks.
End users can choose from a variety of tunneling techniques, including 6to4, Teredo and ISATAP for carrying IPv6 packets over IPv4 networks, but these techniques raise security concerns.