How biased is our validation (data) for AS relationships?
Lars Prehn, Anja Feldmann · 2021
The business relationships between Autonomous Systems (ASes) can provide fundamental insights into the Internet's routing ecosystem. Throughout the last two decades, many works focused on how to improve the inference of those relationships. Yet, it has proven difficult to assemble extensive ground-truth data sets for validation. Therefore, more recent works rely entirely on relationships extracted from BGP communities to serve as "best-effort" ground-truth. In this paper, we highlight the shortcomings of this trend. We show that the best-effort validation data does not cover relationships between ASes within the Latin American (LACNIC) service region even though ~14% of all inferred relationships are from that region. We further show that the overall precision of 96-98 % for peering relationships achieved by three of the most prominent algorithms can drop by 14-25 % when considering only peering relationships between Tier-1 and other transit providers. Finally, we discuss potential ways to overcome the presented challenges in the future.