Loqman Salamatian

2024

1. ACM IMC

   metAScritic: Reframing AS-Level Topology Discovery as a Recommendation System

   Loqman Salamatian, Kevin Vermeulen, Italo Cunha, Vasilis Giotsas, and Ethan Katz-Bassett

   Proceedings of the 2024 ACM on Internet Measurement Conference, 2024

   Abs PDF Slides

   Despite prior efforts, the vast majority of the AS-level topology of the Internet remains hidden from BGP and traceroute vantage points. In this work, we introduce metAScritic, a novel system inspired by recommender system literature, designed to infer interconnections within a given metro. metAScritic uses the intuition that the connectivity matrix at a given metro is a low-rank system, since ASes employ similar peering strategies according to their infrastructures, traffic profiles, and business models. This approach allows metAScritic to accurately reconstruct the complete peering connectivity by measuring a strategic subset of interconnections that capture ASes’ underlying peering strategies. We evaluate metAScritic’s performance across six large metropolitan areas, achieving an average F-score of 0.88 on various validation datasets, including ground truth. metAScritic measures more than 86K edges and infers more than 368K edges, compared to the 13K edges observed for this subset of ASes in public BGP feeds – an increase of (24X) what is currently seen. We study the impact of our inferred links on Internet properties, illustrating the extent of the Internet’s flattening and demonstrating our ability to better predict the impact of route leaks and prefix hijacks, compared to relying only on the existing public view.

2023

1. Communications of ACM

   A Manifold View of Connectivity in the Private Backbone Networks of Hyperscalers

   Loqman Salamatian, Scott Anderson, Joshua Mathews, Paul Barford, Walter Willinger, and Mark Crovella

   Commun. ACM, 2023

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   As hyperscalers such as Google, Microsoft, and Amazon play an increasingly important role in today’s Internet, they are also capable of manipulating probe packets that traverse their privately owned and operated backbones. As a result, standard traceroute-based measurement techniques are no longer a reliable means for assessing network connectivity in these global-scale cloud provider infrastructures. In response to these developments, we present a new empirical approach for elucidating connectivity in these private backbone networks. Our approach relies on using only "lightweight" (i.e., simple, easily interpretable, and readily available) measurements, but requires applying "heavyweight" mathematical techniques for analyzing these measurements. In particular, we describe a new method that uses network latency measurements and relies on concepts from Riemannian geometry (i.e., Ricci curvature) to assess the characteristics of the connectivity fabric of a given network infrastructure. We complement this method with a visualization tool that generates a novel manifold view of a network’s delay space. We demonstrate our approach by utilizing latency measurements from available vantage points and virtual machines running in datacenters of three large cloud providers to study different aspects of connectivity in their private backbones and show how our generated manifold views enable us to expose and visualize critical aspects of this connectivity.

2021

1. Journal of Cybersecurity

   The geopolitics behind the routes data travel: a case study of Iran

   Loqman Salamatian, Frédérick Douzet, Kavé Salamatian, and Kévin Limonier

   Journal of Cybersecurity, 2021

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   In November 2019, in the wake of political demonstrations against the regime, Iran managed to selectively cut off most traffic from the global Internet while fully operating its own domestic network. It seemingly confirmed the main hypothesis our research had led us to, based on prior observation of data routing: Iran’s architecture of connectivity enables selective censorship of international traffic. This paper examines, through the case of Iran, how states can leverage the Border Gateway Protocol (BGP) as a tool of geopolitical control and what are the trade-offs they face. This question raises a methodological question that we also address: how the analysis of BGP can infer and document these strategies of territorialization of cyberspace. The Internet is a network of networks where each network is an autonomous system. Autonomous systems (ASes) are independent administrative entities controlled by a variety of actors such as governments, companies and universities. Their administrators have to agree and communicate on the path followed by packets travelling across the Internet, which is made possible by BGP. Agreements between ASes are often confidential but BGP requires neighbouring ASes to interact with each other in order to coordinate routing through the constant release of connectivity update messages. These messages announce the availability (or withdrawal) of a sequence of ASes that can be followed to reach an IP address prefix. In our study, we inferred the structure of Iran’s connectivity through the capture and analysis of these BGP announcements. We show how the particularities of Iran’s BGP and connectivity structure can enable active measures, such as censorship, both internally and externally throughout the network. We argue that Iran has found a way to reconcile a priori conflicting strategic goals: developing a self-sustaining and resilient domestic Internet, but with tight control at its borders. It thus enables the regime to leverage connectivity as a tool of censorship in the face of social instability and as a tool of regional influence in the context of strategic competition.