Fortifying large scale, geospatial networks: Implications for supervisory control and data acquisition systems

Large scale, geospatial networks-such as the Internet, the interstate highway system, gas pipelines, and the electrical grid-are integral parts of modern society, facilitating the capability to communicate, transport goods and services between locations, and connect homes and businesses to basic necessities like water and electricity. The associated management and protection of this critical infrastructure is a challenging task because it is often compromised or damaged by natural disasters, human error, or sabotage. Further, the cascading effects associated with disruptions can impact related interdependent infrastructure, such as supervisory control and data acquisition systems (SCADA). In this context, although the protection and/or hardening of network elements can reduce disruptive impacts, the cost to protect all equipment in the system is prohibitive. The purpose of this chapter is to detail an optimization approach for selecting elements on a network to be protected, under budget constraints, in order to maximize system performance if one or more components are damaged or destroyed. Applications results for a large scale, geospatial network are explored and presented, illustrating problem complexities as well as the potential for informed strategic investment decision making. The implications for SCADA systems relying on large scale geospatial networks, including the public Internet, are also discussed.