MONITORING OF INTERNETWORK RESILIENCE
The key to inter-domain routing resilience is the establishment of redundancy at multiple physical endpoints and, if possible, also across multiple levels. The most fundamental inter-domain protection concept is the establishment of multihoming, that is, the presence of at least two distinct uplink connections toward non-local destinations. To realize the maximum possible
resilience from such a setup, the critical dependencies of the upstream providers should ideally
be investigated (e.g., where the transit providers’ fibers run, from which grid their equipment is powered, or where they interconnect), but obtaining a comprehensive view of this is frequently difficult.