The active measurements the RIPE NCC carried out on World IPv6 Day on 8 June 2011 included ICMP (Internet Control Message Protocol) and ICMP6 (ICMP for IPv6) measurements from our vantage points to selected hostnames of World IPv6 Day participants and other dual-stacked parties. We used these measurements to determine the performance of IPv4 versus IPv6 connections.

The figure below shows a histogram of all relative IPv4 versus IPv6 performance data points collected during World IPv6 Day. A single data point consists of the ratio of IPv4 and IPv6 performance from a single vantage point to a single destination during a 10-minute interval.

The image shows that while this distribution has a bell shape, it is a little “fatter” on the IPv4 side. This means that IPv4 is faster more often than IPv6. What this tells us is that you are slightly better off in an IPv4-only environment than in an IPv6-only environment. On a dual-stack client that unconditionally prefers IPv6 to IPv4, IPv4 is more often the faster protocol, but this is far from a universal truth. There is also a significant chance that IPv6 is faster, since the “IPv6-is-faster” part of the histogram also has a significant volume.

Note that we measured ICMP and ICMP6, and not HTTP performance. Also, the IPv4 and IPv6 end points for a given hostname may be topologically and/or geographically in (very) different places, especially when proxies are used for IPv6 to IPv4 translation. In cases where the IPv4 and IPv6 destination end points are not at the same location, the distance between a vantage point and either the IPv4 or IPv6 destination end point has a large influence on the measured performance.

In conclusion, we can say that comparable IPv4 and IPv6 performance can be seen as an indication of a mature deployment of both IPv4 and IPv6 in a network. In the data we analysed, we see that IPv4 is still generally faster then IPv6, but for a significant fraction of measurements IPv6 is the faster protocol.

For more detailed information, please refer to the background article on RIPE Labs: Measuring World IPv6 Day—Comparing IPv4 and IPv6 Performance.