Graph resilience improvement of backbone networks via node additions

Backbone networks are critical infrastructure that interconnect networks across cities, countries, and continents. Maintaining and expanding such networks is a progressive task as the number of network users increases. High capacity and availability are amongst the main objectives of backbone networks planning because they serve critical services in healthcare, business, and education. Disrupting these services can have catastrophic effects on people's daily activities. Targeted attacks are among several challenges that can disconnect backbone networks. Designing resilient networks against such attacks can save money and lives. Improving the resilience of existing networks can be obtained by adding more nodes and links. In this paper, we propose a heuristic algorithm to improve the resilience of a given graph by adding a set of nodes and links to meet given objective functions such as maximizing algebraic connectivity, minimizing network criticality, and weighted spectral distribution. Moreover, we apply our algorithm to several US-based backbone networks and evaluate their improved network resilience against centrality-based attacks. Our results show that adding links to maximizing algebraic connectivity yields better network resilience than minimizing network criticality and weighted spectral distribution.