acm sigcomm

The topic of Internet eXchange Points (IXPs) has attracted growing interest in the last few years as our community becomes aware of their increasingly central role in the Internet, from interdomain connectivity and overall network structure to performance and economics. Anyone starting to look at the topic (there’s plenty to take on) quickly becomes aware of the dearth of publicly available information, the value of three main datasets – from PeeringDB, the European Internet Exchange Association (Euro-IX) and the Packet Clearing House (PCH), and the pain that dealing with them entails. For the intrepid, this article should ease some of that pain. The authors present the first analysis and detailed cross-comparison of these three public datasets. They analyze data from between 500 and 700 IXPs found in each of the different sources and highlight the similarities, complementary information and discrepancies they found. For those considering doing work in the area, the authors are also sharing the combined data as well as the code used for data collection and analysis. Not everything is resolved, of course, and there is still much pain to cope with. The reviewers point to the fact that the sources are far from rigorous, manual inspection is needed and question the ability of the code to handle discrepancies that exist between the different datasets. As the authors note, a fully automated approach to linking all IXPs may not be desirable given the many ambiguous mappings (one of my favorites – “SIX” occurs as an identifier with minor variations 5 times in PeeringDB with the “S” standing alternatively for Seattle, Stuttgart, Slovak, Slovenia and Stavanger, all of them different IXPs!). There is also potential linkage between these datasets to an extent not yet clear and the clearly difficult problem of getting to the elusive ground truth. All said, this is a good, very welcome step forward and the community should appreciate the effort.