Researcher: Osman Yagan
Research Area: Next Generation Secure and Available Networks
Today’s Internet is one of the largest and the most complex systems ever created. Complexity is now the limiting constraint in the design, engineering, and operation of large-scale networks and communication protocols. A direct consequence of complexity is that the correctness, security, and availability of the Internet cannot be guaranteed. For example, a failure in one part of the Internet may cause wide spread failures and performance degradation of critical services in a very different part of the network. A major consequence of such interdependence is that systems and networks are often more fragile in the face of node failures, attacks, and natural hazards than their isolated counterparts. For example, failures in one network or network node may propagate to other networks and vice versa, leading to a cascade of failures that could potentially collapse an entire infrastructure. However, most existing network-science research focuses on single, isolated networks, and thus lacks the methods and tools necessary to address vulnerabilities of even simple interdependent networks. In fact, limited preliminary research on networks of networks has already demonstrated great potential for advancing the state of the art in building robust and resilient systems. Preliminary findings suggest that there are unprecedented differences in the behaviors of networks of networks as compared to individual networks. For instance, CMU research has already demonstrated that a network design that is optimal in countering adversarial attacks in a single network could be a catastrophic choice for the resiliency of interdependent networks.
We envision several advances through interdisciplinary research combining theoretical analyses with empirical studies and algorithm design. Specific expected research outcomes would include i) design parameters and conditions that achieve optimal robustness and resiliency in a network of networks against random attacks as well as targeted attacks, ii) accurate interdependent network models motivated by real-world applications, iii) accurate and realistic node-failure models inspired by practical cases, iv) new metrics to evaluate robustness in interdependent structures, v) algorithms to determine the vulnerable points in an interdependent network, vi) recovery and healing strategies for systems that are under attack, and vii) robustness analysis of systems that are under physical and cyber attack simultaneously.