Quiz:

From the number of IPv6-enabled households to the amount of IPv6 traffic carried by ISPs, the United States has made enormous strides during the last two years. Indeed, the latest statistics indicate that the United States is the global leader in several categories, including the amount of IPv6-enabled users, Web content and networking products. [See sidebar]

"The U.S. has put a lot of effort into IPv6," says Christine Schweickert, senior engagement manager for public sector at Akamai, a leading content delivery network. "Government agencies were putting pressure on the big networking vendors. They were pushing all the major telco providers and requiring them to put IPv6 in their road maps...It was a strategic move on their part."

is an upgrade to the Internet's addressing scheme, which was created using a protocol 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 can support a virtually limitless number of devices: 2 to the 128th power. IPv6 is necessary because the Internet is running out of IPv4 addresses. However, IPv6 is not backwards compatible with IPv4, requiring network operators to support both protocols at an added cost.

One sign of U.S. progress in IPv6 is that there are now three U.S. carriers - Verizon , AT&T and Comcast - that are among the top six ISPs carrying the majority of the world's IPv6 traffic. Around 15% of Verizon Wireless customers, 6% of AT&T's DSL customers and 2.5% of Comcast broadband customers are using IPv6.