Creating network resilience against disasters using Service Level Agreements

Building networks that are resilient to natural disasters and other geographically correlated events involves both proactive network design and remediation after the event. Network provisioning is one of the steps used to provide redundancy and diversity in networks that are key elements in resilient network design. Once the disaster has occurred, remediation may include rerouting of the most important services affected by the event. Both components involve understanding the quality of service that may be affected, knowing which services are critical, and having an understanding of the geographic events that may impact the network. Furthermore, if resources are limited following the disaster, how do we select which services to reroute? In this work, we propose to use Service Level Agreements (SLA) to provide much of the information necessary to solve the provisioning and rerouting problems. On the provisioning side, the SLAs will provide the required system response time, availability and survivability of a service. On the remediation side, the SLA can provide the priority of a service to restore and reroute. We present mixed-integer linear programming (MILP) models and heuristics to show how the most important services are provisioned and rerouted to be available in the event of a geographic disaster. Our approaches are found to be more efficient than other priority-based approaches.