Riskroute: A Framework For Mitigating Network Outage Threats

A comprehensive understanding of outage threats is critical for robust network design and operation, and evaluating cost trade-offs for recovery planning. In this paper, we describe a study of network infrastructure events due to outage events and a framework for mitigating these risks through backup routing and additional provisioning. We evaluate risk via the concept of bit-risk miles, the geographically-scaled outage risk of traffic in a network. Our focus on bit-riskmiles allows for first-of-its-kind analysis of the tradeoffs of shortest path routing and risk-averse routing. We leverage the concept of bit-risk miles to present RiskRoute, a flexible routing framework that allows for backup routes to be configured to respond to both historical and immediately forecasted outage threats. Specifically, RiskRoute is an optimization framework that minimizes bit-risk miles between arbitrary points in a network. RiskRoute also reveals the best locations for provisioning additional network infrastructure in the form of new PoP-to-PoP links for single-network domains, and the best new peering relationships for multi-network domains. To assess and evaluate RiskRoute, we assemble diverse data sets including (i) - detailed topological maps and peering relationships of Internet Service Providers (ISPs) in the US, and (ii) - historical information on different types of natural disasters which threaten physical infrastructure. Our analysis reveals the providers that have the highest risk to disaster-based outage events. We also provide provisioning recommendations for network operators that can in some cases significantly lower bit-risk miles for their infrastructures.