On geographic coordinates of PlanetLab Europe

PlanetLab is a global IP research network of computers located across the world. The primary aim of PlanetLab is to support evaluation and deployment of new IP communication technologies. Due to its global scale, PlanetLab is used as an experimental testbed for a number of geographically oriented research. Therefore, the geographical properties of the PlanetLab nodes are of significant importance for correct and trustworthy results of the experiments. In the paper, we analyse the geographical properties of PlanetLab Europe, which is the European part of the PlanetLab global network. It describes different methods used for estimating the location information correctness provided for the PlanetLab nodes. The results show that the nodes' location is commonly burdened with an error varying from units to hundreds of kilometres. We propose a location uncertainty index to assist the PlanetLab users with a proper selection of the nodes for their experiments. The location index allows a selection of the nodes for the experiments requiring diverse input location accuracy data. We used the proposed index to evaluate the location accuracy of the PlanetLab Europe nodes. We estimate that below 1 % of the active PlanetLab Europe nodes have a maximum location error less than 1 km, 42 % less than 5 km, 60 % less than 10 km, and 85 % less than 100 km.