A Novel Methodology to Address the Internet AS-Level Data Incompleteness

In the last decade, many studies have used the Internet autonomous system (AS)-level topology to perform several analyses, from discovering its graph properties to assessing its impact on the effectiveness of worm-containment strategies. Yet, the Border Gateway Protocol (BGP) data used to reveal the topologies are far from complete. Our contribution is threefold. First, we analyze BGP data currently gathered by the most famous route collector projects, highlighting and explaining the causes of their incompleteness. We found that large areas of the Internet are not properly captured due to the geographical location of route collector feeders and due to BGP filters, such as export policies and decision processes. Second, we propose a methodology based on a new metric, named p2c-distance, which is able to: 1) identify the minimum number of ASs required to obtain an Internet AS-level topology that is closer to reality; and 2) identify a ranking list of these ASs to show that it is possible to obtain nonnegligible coverage improvements with a limited number of appropriately chosen feeding ASs. Third, we characterize the ASs that were found to be part of the solution of the above covering problems. We found that the route collectors are rarely connected to these ASs, thus highlighting that much effort is needed to devise a route collector infrastructure that ideally would be able to capture a complete view of the Internet.