TopoScope: Recover AS Relationships From Fragmentary Observations

Knowledge of the Internet topology and the business relationships between Autonomous Systems (ASes) is the basis for studying many aspects of the Internet. Despite the significant progress achieved by latest inference algorithms, their inference results still suffer from errors on some critical links due to limited data, thus hindering many applications that rely on the inferred relationships. We take an in-depth analysis on the challenges inherent in the data, especially the limited coverage and biased concentration of the vantage points (VPs). Some aspects of them have been largely overlooked but will become more exacerbated when the Internet further grows. Then we develop TopoScope, a framework for accurately recovering AS relationships from such fragmentary observations. TopoScope uses ensemble learning and Bayesian Network to mitigate the observation bias originating not only from a single VP, but also from the uneven distribution of available VPs. It also discovers the intrinsic similarities between groups of adjacent links, and infers the relationships on hidden links that are not directly observable. Compared to state-of-the-art inference algorithms, TopoScope reduces the inference error by up to 2.7-4 times, discovers the relationships for around 30,000 upper layer hidden AS links, and is still more accurate and stable under more incomplete or biased observations.