Can’t reach your favorite site? IPv6 may be to blame

FRAMINGHAM, Mass. — A small number of Internet users will experience delays or time-outs today as they attempt to visit Facebook, Google, Yahoo and other popular Web sites due to the 24-hour IPv6 trial.

Estimates of how many will experience problems with IPv6 range from 0.03 per cent to 0.05 per cent of all Internet users — or as many as 1 million of the Internet’s 2 billion users worldwide.

IPv6, which features an expanded addressing scheme, is an upgrade to the Internet’s main communications protocol, which is known as IPv4.

Internet engineers have dubbed this problem “IPv6 brokenness.” The term refers to PCs and smartphones that have IPv6 addresses and run operating systems such as Apple Mac OS X or Microsoft Windows 7 that default to IPv6. However, these systems do not have end-to-end IPv6 connectivity due to misconfigurations somewhere along their paths to the Internet.

 

Broken IPv6 connections will cause these systems to suffer delays and timeouts when they try to visit websites running IPv6.
The problem of IPv6 brokenness will be significant today because there are at least 418 corporations, universities and government agencies participating in a large-scale trial of IPv6 known as World IPv6 Day. One of the primary goals of World IPv6 Day, which is being sponsored by the Internet Society, is to determine the magnitude of IPv6 brokenness.

“The one thing we want to measure on World IPv6 Day is what’s the percentage of users that have IPv6 brokenness and for what reason,” says Alain Fiocco, leader of the IPv6 program at Cisco Systems Inc., which is participating in the IPv6 trial. “Right now, we think this number is a very, very small percentage. But this [test] has never been done at global scale. …We need to find out if it’s a big problem or a small problem.”

Experts say that most Internet users will have no difficulty reaching Web content on June 8 because they have IPv4 addresses and IPv4 connectivity.

“The average home user is not going to be aware of [World IPv6 Day],” says Hari Krishnan, director of product management at Nominum, a DNS vendor that is working with several ISPs to prepare for World IPv6 Day and is a World IPv6 Day participant, too. “They have IPv4 connectivity so they wouldn’t see any impact.”

“We are going to see pockets of problems, but I think by and large the experiment will be transparent,” agrees Andy Champagne, vice president of engineering at Akamai, a content delivery network that carries anywhere from 15 to 30 per cent of Internet traffic for sites such as Fox Interactive and USA Today. “Some users will be impacted … but based on projections of error rates, we don’t expect it to be serious.”

Internet users who do experience IPv6 brokenness may include residential customers participating in IPv6 trials through their ISPs or running IPv6 tunneling mechanisms. Employees of enterprises, universities and government agencies that have IPv6 services on their networks also may experience trouble if devices such as firewalls aren’t configured properly for IPv6 traffic.
“The vast majority of those issues are going to be around people using 6to4 [tunneling] in a broken configuration — broken meaning that the home network is misconfigured or the operating system has an irregular setting,” predicts John Brzozowski, distinguished engineer and chief architect for IPv6 at U.S. cable company Comcast Corp.

 

Another issue that could disrupt Internet service is a lack of peering arrangements between carriers that will cause inefficient routing of IPv6 traffic. For example, Cogent does not have an IPv6 peering arrangement with Hurricane Electric, which operates one of the Internet’s most-connected IPv6 backbones and provides a popular IPv6 tunneling broker. Similarly, Level 3 Communications reportedly lacks peering arrangements for IPv6 traffic with some carriers.

The lack of peering arrangements could cause delays because IPv6 traffic won’t travel from the sender to the destination in the most optimal route.