Spatial Dispersion of Interconnection Clusters in the European Internet

This paper studies the effects of geographical distance on the interconnection agreements between providers participating at Internet Exchange Points (IXPs) in Europe. We assess separately two main issues: the extent of existing clustering, as well as the role of proximity in bilateral interconnection decisions. Our results show the dominance of spatial random patterns in the interconnection agreement distributions. On the other hand, we find that proximity positively affects the probability of establishing interconnection for all the IXPs studied but one. Interesting, the latter is the only one showing an initially clustered morphology. This indicates a prevalence of centripetal forces — local spillovers and mutual knowledge — over geographical differentiation for any pre-existing interconnection pattern morphology except the clustered ones