Disjoint in Name Only: Illusory Resilience in the Internet

Overview & Synopsis

Internet path diversity is usually verified at the logical layer: two alternatives may share no AS or IP link yet traverse the same facility, conduit, or submarine landing zone. We call this gap illusory resilience and define the Illusory Resilience Index (IRI) as the latent hazard-weighted physical overlap of a logically disjoint path pair. To detect such hidden exposure without carrier underlay maps, we audit three public signals: correlated BGP withdrawals during documented physical incidents, operator interconnection-footprint overlap, and shared submarine landing zones. Two signals survive calibration; the 60-second BGP signal does not. Across 47 operators in ten regions, same-region pairs have substantially greater listed facility overlap than cross-region pairs, and one Marseille campus colocates 153 operator pairs. Across 68 cable systems in twelve corridors, 31-100% of candidate within-corridor pairs share a 25 km coastal hazard zone; two corridors are fully saturated, and the same rule recovers ten of eleven cable pairs documented as co-damaged in 2024. The rejected temporal predicate has a 0.444 null firing rate and no hits among twelve monitored positive pairs. Public data therefore expose substantial shared-risk structure behind nominal diversity and identify where stronger physical-path verification is warranted.