Telecom dependency is a service relationship in which an organization depends on a carrier or communications provider for connectivity, voice, messaging, or network transport. That dependency may be direct, such as a primary circuit, or indirect, such as a wholesale reseller, interconnection partner, or signaling path.
It matters because telecom providers can become part of the trust chain for sensitive traffic. If a dependency is poorly documented, a restricted provider, legacy route, or third-party carrier may still touch business communications after policy changes. Attackers can abuse these hidden paths for interception, disruption, or traffic redirection, while defenders use dependency mapping to identify exposure, verify routing, and reduce residual trust. In practice, telecom security starts with knowing exactly which carriers can carry your data.