4 research outputs found
Stable and Practical AS Relationship Inference with ProbLink
Knowledge of the business relationships between Autonomous Systems (ASes) is essential to understanding the behavior of the Internet routing system. Despite significant progress in the development of sophisticated relationship inference algorithms, the resulting datasets are impractical for many critical real-world applications, cannot offer adequate predictability in the configuration of routing policies, and suffer from inference oscillations. To achieve more practical and stable relationship inferences we first illuminate the root causes of the contradictions between these shortcomings and the near-perfect validation results of AS-Rank, the state-of-the-art relationship inference algorithm. Using a "naive" inference approach as a benchmark, we find that the available validation datasets over-represent AS links with easier inference requirements. We identify which types of links are harder to infer, and we develop appropriate validation subsets to enable more representative evaluation. We then develop a probabilistic algorithm, ProbLink, to overcome the inference barriers for hard links, such as non-valley-free routing, limited visibility, and non-conventional peering practices. To this end, we identify key interconnection features that provide stochastically informative and highly predictive relationship inference signals. Compared to AS-Rank, our approach reduces the error rate for all links by 1.6\times×, and importantly, by up to 6.1 times for different types of hard links. We demonstrate the practical significance of our improvements by evaluating their impact on three applications. Compared to the current state-of-the-art, ProbLink increases the precision and recall of route leak detection by 4.1 times and 3.4 times respectively, reveals 27% more complex relationships, and increases the precision of predicting the impact of selective advertisements by 34%
Understanding the confounding factors of inter-domain routing modeling
The Border Gateway Protocol (BGP) is a policy-based protocol, which enables Autonomous Systems (ASes) to independently define their routing policies with little or no global coordination. AS-level topology and AS-level paths inference have been long-standing problems for the past two decades, yet, an important question remains open: "which elements of Internet routing affect the AS-path inference accuracy and how much do they contribute to the error?". In this work, we: (1) identify the confounding factors behind Internet routing modeling, and (2) quantify their contribution on the inference error. Our results indicate that by solving the first-hop inference problem, we can increase the exact-path score from 33.6% to 84.1%, and, by taking geolocation into consideration, we can refine the accuracy up to 94.6%
BGP-Multipath Routing in the Internet
BGP-Multipath, or BGP-M, is a routing technique for balancing traffic load in the Internet. It enables a Border Gateway Protocol (BGP) border router to install multiple ‘equally-good’ paths to a destination prefix. While other multipath routing techniques are deployed at internal routers, BGP-M is deployed at border routers where traffic is shared on multiple border links between Autonomous Systems (ASes). Although there are a considerable number of research efforts on multipath routing, there is so far no dedicated measurement or study on BGP-M in the literature. This thesis presents the first systematic study on BGP-M. I proposed a novel approach to inferring the deployment of BGP-M by querying Looking Glass (LG) servers. I conducted a detailed investigation on the deployment of BGP-M in the Internet. I also analysed BGP-M’s routing properties based on traceroute measurements using RIPE Atlas probes. My research has revealed that BGP-M has already been used in the Internet. In particular, Hurricane Electric (AS6939), a Tier-1 network operator, has deployed BGP-M at border routers across its global network to hundreds of its neighbour ASes on both IPv4 and IPv6 Internet. My research has provided the state-of-the-art knowledge and insights in the deployment, configuration and operation of BGP-M. The data, methods and analysis introduced in this thesis can be immensely valuable to researchers, network operators and regulators who are interested in improving the performance and security of Internet routing. This work has raised awareness of BGP-M and may promote more deployment of BGP-M in future because BGP-M not only provides all benefits of multipath routing but also has distinct advantages in terms of flexibility, compatibility and transparency