Nation-State Routing: Censorship, Wiretapping, and BGP

The treatment of Internet traffic is increasingly affected by national policies that require the ISPs in a country to adopt common protocols or practices. Examples include government enforced censorship, wiretapping, and protocol deployment mandates for IPv6 and DNSSEC. If an entire nation’s worth of ISPs apply common policies to Internet traffic, the global implications could be significant. For instance, how many countries rely on China or Great Britain (known traffic censors) to transit their traffic? These kinds of questions are surprisingly difficult to answer, as they require combining information collected at the prefix, Autonomous System, and country level, and grappling with incomplete knowledge about the AS-level topology and routing policies. In this paper we develop the first framework for country-level routing analysis, which allows us to answer questions about the influence of each country on the flow of international traffic. Our results show that some countries known for their national policies, such as Iran and China, have relatively little effect on interdomain routing, while three countries (the United States, Great Britain, and Germany) are central to international reachability, and their policies thus have huge potential impact.

💡 Research Summary

The paper introduces a novel framework for analyzing Internet routing at the country level, aiming to quantify how national policies—such as censorship, wiretapping, and mandated protocol deployments—affect the flow of international traffic. The authors begin by collecting a comprehensive set of BGP routing tables from multiple points in time, then map each advertised IP prefix to its originating Autonomous System (AS) and, subsequently, to the country that operates that AS. To improve the reliability of this AS‑to‑country mapping, they cross‑reference WHOIS records, Internet Routing Registry (IRR) entries, PeeringDB data, and GeoIP databases, applying confidence weights and manual verification where sources disagree.

With this enriched dataset, the authors construct a directed graph whose nodes represent sovereign states and whose edges represent the volume of traffic that traverses from one country to another according to the best‑path BGP selections. They define a new metric called Country Centrality (CC). CC measures the proportion of destination prefixes that cannot be reached without passing through a given country, effectively capturing the structural indispensability of that country within the global inter‑domain routing fabric.

Applying the framework to a snapshot covering roughly 260 countries and over 70,000 ASes, the study yields several striking findings. The United States emerges as the dominant hub, appearing on more than 30 % of all best‑path routes and achieving the highest CC score. Great Britain and Germany follow, accounting for roughly 12 % and 9 % of routes respectively, and ranking second and third in CC. In contrast, nations commonly associated with heavy Internet censorship—most notably Iran and China—exert relatively modest influence: Iran’s ASes appear on fewer than 2 % of routes and China on under 4 %, with correspondingly low CC values. This suggests that while these countries may heavily filter domestic traffic, they do not serve as critical transit points for the bulk of global traffic.

Regional analysis reveals additional nuances. The United Kingdom functions as a primary conduit for many smaller European states, many of which lack direct peering relationships and therefore rely on UK‑based transit providers. Germany occupies a similar bridging role between Central/Eastern Europe and Asian networks. These observations underscore that the “censorship power” of a nation is not solely a function of its internal policies but is amplified when the nation also occupies a structurally central position in the worldwide routing topology.

From a policy perspective, the authors argue that the potential global impact of national routing policies is concentrated in the hands of the few countries with high CC scores. Consequently, transparency, accountability, and security measures (e.g., widespread adoption of RPKI and other BGP security extensions) in the United States, United Kingdom, and Germany become matters of international concern. The paper calls for multilateral governance mechanisms that can monitor and, where appropriate, constrain the ability of these “core transit” nations to unilaterally impose censorship or surveillance that would ripple across the global Internet.

The study also acknowledges several limitations. The AS‑to‑country mapping is imperfect due to incomplete WHOIS data, private peering agreements, and the dynamic nature of routing policies. Moreover, the analysis is based on static snapshots of BGP tables, which may not capture transient routing changes or policy-driven path alterations. To address these gaps, the authors propose future work that integrates real‑time BGP updates with traffic‑level measurements such as NetFlow or sFlow, enabling a dynamic, time‑sensitive version of the Country Centrality metric. They also suggest scenario‑based simulations to explore how deliberate policy changes (e.g., a nation imposing a new routing filter) would propagate through the global routing graph.

In summary, this paper delivers the first systematic, data‑driven assessment of country‑level influence on inter‑domain routing. By quantifying the structural centrality of each nation, it reveals that the United States, Great Britain, and Germany wield disproportionate power over international reachability, while countries traditionally viewed as “censors” have limited leverage in the broader routing ecosystem. The findings have profound implications for Internet governance, security, and the preservation of a free and open global network.