Date Added: Aug 2012
The Internet was designed to always find a route if there is a policy-compliant path. However, in many cases, connectivity is disrupted despite the existence of an underlying valid path. The research community has focused on short-term outages that occur during route convergence. There has been less progress on addressing avoidable long-lasting outages. The authors' measurements show that long-lasting events contribute significantly to overall unavailability. To address these problems, they develop LIFEGUARD, a system for automatic failure localization and remediation. LIFEGUARD uses active measurements and a historical path atlas to locate faults, even in the presence of asymmetric paths and failures.