Improving Routing Security for Global Research and Education#

steven wallace — Internet2.edu (with CAIDA, per ROOTBEER/NSF CICI)

• Why: R&E networks deterministically prefer R&E routes over commodity, which makes their route leaks high-impact (US scientific traffic transiting unintended international paths). Beyond the R&E story, this is a template for measuring local-pref policies you cannot see in public BGP views.
• What: A measurement system that announces the same prefix from two origins — one via an R&E path (Internet2), one via commodity transit — with varying AS-path prepends, then pings responsive hosts to infer which route each of ~2,600 R&E ASes actually chose. June 2025 results: 80.8% of prefixes/75.3% of ASes always used the R&E route regardless of prepending; 7% always commodity; ~9% switch by AS-path length (implying equal local-pref). Real 2024 incidents documented: a South American R&E network leaking commercial routes (traffic rerouted through South America) and a Middle East member leaking R&E routes to a commercial provider (cloud return traffic transiting the Middle East, some members withdrawing specifics defensively).
• How: Building on this, the ROOTBEER project is constructing an operational routing-security observatory at Internet2 — leak detection between R&E and commodity, a stakeholder dashboard, and a move toward an actively maintained public route filter on all peers, shareable by other R&E transit networks.
• Where applicable: R&E-specific topology (route-preference policy), and public BGP visibility is thin here (only 27 of 2,659 R&E ASes provide RouteViews/RIS views). The dual-origin measurement technique, though, transfers to any policy-visibility problem, and the public-filter approach is a model for any community network with trusted transit.