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How to make your “Eyeballs Happy”

Cisco has taken a leadership role in driving the industry on the creation of standards associated with IPv6. At recent count we had over 458 RFCs related to IPv6 – over a third of the total!

One example of this is how our technical leaders have taken on the challenge in dual stack (IPv4 and IPv6) networks to reduce user-noticeable delays in when the IPv6 path is broken or slow. We’ve documented a method called “Happy Eyeballs” as described in Internet-Draft “Happy Eyeballs: Trending Towards Success (IPv6 and SCTP”).

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Happy Eyeballs for World IPv6 Day

Imagine how “happy” your eyeballs would become when you realize that your Internet connection failover time was drastically reduced from a full minute to less than half a second, Dan Wing and Andrew Yourtchenko of Cisco developed a methodology to do just that.

The Internet is changing. Network operators and content providers are beginning the widespread global deployment of IPv6, while keeping IPv4 up and running until IPv6 is ready to take over. Dan and Andrew have contributed to the cause of easing the adoption of IPv6 by documenting a methodology that will enable client applications to react more responsively in dual-stack failure scenarios by aggressively rectifying intermittent access issues and therefore preserve the end user experience for dual-stack IPv4 and IPv6 devices. This solution is documented in their IETF draft, cleverly named Happy Eyeballs. It is designed to keep the eyeballs of a computer end user “happy” in the face of problems that may exist when a host is attempting to establish IPv4 or IPv6 connectivity. The IETF draft document describes how client applications should behave when establishing IPv6 and IPv4 connectivity simultaneously, preferring IPv6 if the connectivity is successful, and disconnecting any remaining redundant (IPv4 / TCP) connections. By failing over quickly from IPv6 to IPv4, or from IPv4 to IPv6, the user is not affected by problems that occur in only one of the two IP versions in a dual-stack deployment. This can greatly reduce the connection times in problematic situations -- from minutes to milliseconds, compared to the typical behavior in many implementations today.

In anticipation of World Ipv6 Day, Google Chrome has adopted a similar approach to what Dan and Andrew have documented, under the somewhat less light-hearted name “IPv4-Fallback”. This modification promises to ease potential trouble spots on World IPv6 Day, as well as future browser interactions with dual-stack network configurations. Google’s Internet browser, Chrome 11, uses a “hybrid” variation of Happy Eyeballs that is responsible for establishing, monitoring, and management of simultaneous parallel IP connections. This software enhancement produces significant results by reducing the fallback latency of a problematic IPv6 connection from between 20 and 75 seconds as is often seen today, to as little as 300 milliseconds.

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