We present Hubble, a system designed to identify and diagnose reachability problems on the Internet in real-time. Using Hubble, we are able to evaluate the extent to which global reachability is violated: how many prefixes are reachable from some vantages and not others, and how long do these problems persist?
Whereas previous work focused on either reachability within a single AS or simple passive monitoring of BGP updates, we have designed Hubble to unify RouteViews and distributed vantage points into a system that can perform active probe monitoring and diagnosis of reachability problems to about 90% of the Internet's edge prefixes. Our results show that 10% of prefixes experience reachability problems on a given day.
Beyond identifying problems, Hubble gathers data and can trigger measurements to help troubleshoot and categorize commonly occuring reachability problems in real-time. Is a prefix currently unreachable from portions of the Internet? Is the problem due to issues with multi-homed failover? Is some AS dropping all traffic to the prefix? Hubble can provide answers to these questions.
