The Revenge of Distance: Vulnerability Analysis of Critical Information Infrastructure

Internet Reliability with Realistic Peering

Peering between network providers is modeled as a set of interconnections at hub nodes. The paper employs probabilistic methods to determine the likelihood of a path between nodes, under a variety of simulated disruptions or failures of parts of a network. Reliability is measured as the probability of withstanding failure of network components such as nodes or linkages. A reliability envelope is devised in order to define a range of impacts—with the recognition that the damage to subsets of the network can vary from a relatively benign effect to a much more critical or lethal impact. Thus, we describe a range of scenarios from best to worst, within the same level of infrastructure loss. With the use of simulation data for the United States, results show the critical role of major hubs in sustaining communication among cities. In the paper we highlight especially reliable nodes (for example, Chicago and Atlanta) and those that are most susceptible (for example, Birmingham, Alabama, and Nashville, Tennessee). Failure in major hub cities such as Chicago, Dallas, and San Francisco would significantly influence adjacent areas and could cause severe degradation for the entire network with a loss of resiliency to below tolerable levels. An important finding is that various patterns in the reliability envelope can be influenced by factors such as network structures, hub structures, and geographical locations.

On some recent definitions and analysis frameworks for risk, vulnerability, and resilience

Recently, considerable attention has been paid to a systems-based approach to risk, vulnerability, and resilience analysis. It is argued that risk, vulnerability, and resilience are inherently and fundamentally functions of the states of the system and its environment. Vulnerability is defined as the manifestation of the inherent states of the system that can be subjected to a natural hazard or be exploited to adversely affect that system, whereas resilience is defined as the ability of the system to withstand a major disruption within acceptable degradation parameters and to recover within an acceptable time, and composite costs, and risks. Risk, on the other hand, is probability based, defined by the probability and severity of adverse effects (i.e., the consequences). In this article, we look more closely into this approach. It is observed that the key concepts are inconsistent in the sense that the uncertainty (probability) dimension is included for the risk definition but not for vulnerability and resilience. In the article, we question the rationale for this inconsistency. The suggested approach is compared with an alternative framework that provides a logically defined structure for risk, vulnerability, and resilience, where all three concepts are incorporating the uncertainty (probability) dimension.