When the Internet was created more than 30 years ago, 4.3 billion unique addresses seemed more than enough. But what started as an "experiment" within the U.S. Department of Defense's Advanced Research Projects Agency (DARPA) has morphed into the mega global communications network we know today.
Since 1981, Internet Protocol version 4, or IPv4, has formed the backbone upon which the Internet is based. IPv4 uses 32-bit addresses to uniquely identify every computer, smart phone, or other device connected to the Internet. The entities responsible for allocating IP address space are the Internet Corporation for Assigned Names and Numbers (ICANN) and the Internet Assigned Numbers Authority (IANA). IANA allocates IP addresses to five regional registries, which in turn distribute the addresses to Internet service providers. The last block of the remaining addresses was allocated to the registries earlier this month.
The transition to a new protocol that will support a virtually unlimited number of devices on the Internet is currently underway. Whereas IPv4 uses 32 bits for each IP address and can support 4,294,967,296 addresses, IPv6 uses 128-bit addresses to support approximately 340 undecillion unique number sequences (that's 340 with 36 zeroes after it).
To help ease the transition to IPv6, some Internet providers are issuing dual-mode cable modems that support both protocols. A standard from American National Standards Institute (ANSI) member and accredited standards developer the Society of Cable Telecommunications Engineers (SCTE), ANSI/SCTE 140 2007, Cable Modem IPv4 and IPv6 eRouter Specification, allows both IPv4 and IPv6 enabled devices to gain connectivity to the Internet.
The development of IPv6 is being led by the Internet Engineering Task Force (IETF), a community of network designers, operators, vendors, and researchers concerned with the evolution of Internet architecture and the smooth operation of the Internet. IETF develops Internet protocols, cooperating where possible with the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) Joint Technical Committee (JTC) 1 on relevant projects. The U.S. plays a leading role in the work of JTC 1, with ANSI serving as secretariat and ANSI member and accredited standards developer the InterNational Committee for Information Technology Standards (INCITS) administering the U.S. Technical Advisory Group (TAG) to JTC 1.