Ookla's Speedtest Throughput Measures

We are interested in validating/comparing the PingER derived throughputs with those obtained by the Ookla Speed test measurements. I therefore contacted Ookla by email on November 27, 2007 and they were kind enough to reply and December 6, 2007, and provide data suitable for importing into Excel (CSV format) and analyzing. Ookla maintains a fleet of speed-testing servers all over the world. A user chosen server downloads a file of incompressible data  to the user's clinet and then uploads it. They calculate the throughput by knowing the amount of data transferred and then dividing this by the time taken to transfer the data in each direction.  A summary of this data is provided to the client user in real-time showing average download speed, upload speed, and ping time, which is the time it takes, in milliseconds, to send a packet of data from the server to the client computer and back.

The data is also archived together with the location of the client. This is s determined based on the client IP address. Speedtest.net uses GeoIP databases from MaxMind to position the client and by default locate the closest server since the transfer speed depends on the TCP window and it is not usually optimized for increased Round Trip Time (RTT). While the information in MaxMind's GeoIP databases is very accurate, it is not perfect. More information on Ookla's speed test can be found here.

Ookla then uses the 95th percentile speeds for the IP address of each client. This way if a connection speed improves over time (or a better testing server for the region is added), it will improve the overall results. The same can be said for degradation of speed. These 95th percentile speeds are then what are averaged to determine the speeds shown in their data set. The ip_addresses column is the number of unique IP addresses from a specific country that have taken a test at Speedtest.net. The file provided contained aggregated data with one line for each country. It included data from 174 countries. The columns contained: the Top Level Domain, the Country name, the number of IP addresses, the average donload speed in kbits/s, the average upload speed in kbits/s. The data for each country was from >= 100 IP addresses.

A rough summary of the results shows: US has most IP addresses = 5.7M. Highest download speed is Japan=11Mbits/s, followed by Sweden, Latvia, Romania, Netherlands, Bulgaria, Singapore, Germany, France, US. Slowest download speed is Cameroon (199kbits/s) followed by Mauritius, Botswana, Angola, Madagascar, Nepal, French Polynesia, New Caledonia, Tanzania, Kenya (i.e. bottom 5 in Africa). Fastest upload is Japan (5.1Mbits/s) followed by Russia, Romania, Sweden, Bulgaria, Latvia, Hong Kong, Lithuania, S. Korea, Moldova. The large number of Eastern European countries is interesting and not understood. The slowest download speeds are Madagascar (70kbits/s), followed by Yemen, Angola, Cameroon, New Caledonia, Botswana, Uruguay, Nepal, Zambia, French Polynesia (276 kbits/s). 50% of the slowest 10 download speed countries are in Africa.The median upload speed (303kbis/s) is 1/3 of the median download speed. Currently the African representation by country is only 26 (out of I think 54). It will be interesting to see if this improves as more measurements are made.

A map of the Ookla throughputs measured for clients in the various countries of the world is shown below. The poor coverage for Sub-Saharan Africa (there was no data for countries in white) is seen as is the much better performance for developed regions such as N. America, Europe, Japan and Australaisia compared to developing regions.

A comparison of  the Ookla upload versus download throughput speeds is seen below on the left. In all cases the download exceeds the upload speed. The best value for the ratio of up/down is 80% (Azerbaijan). the worst is 9% (Portugal), the median is 34% +- 17%. It is seen that several Eastern European countries such as Russia, Romania, Bulgaria, and Moldova  have anomalously high upload throughput speeds.  Also several countries in Western Europe such as Portugal, Belgium, France and Germany have anomalously low upload throughput speeds.

To validate whether the order of magnitude of the throughputs measured by Ookla agreed with those derived from the PingER losses and Round Trip Time (RTT) measurements we plotted the Ookla speedtest download measurements versus the Normalized Derived throughputs (NDT) from Pinger.  It is seen that the order of magnitudes agree and there is a good positive correlation (R2 ~ 0.53). To see how well the Ookla speedtest download results agreed with those of the ZDnet's Australia Speedtest (though the name Speedtest appears in both they are not related) we also plotted the two speedtests against one another. As a comparison we also show the ZDnet Speedtest results vs. the PingER NDT.