Although network virtualization can improve security by isolating traffic from different networks, routers and links are still vulnerable to attacks on the underlying network. High capacity physical links, in particular, constitute good targets since they may be important for a large number of virtual networks. Previous work protects virtual networks by setting aside backup resources. Although effective, this solution increases the cost to infrastructure providers. In this paper, we present a virtual network embedding approach which enables resilience to attacks and efficiency in resource utilization. Our approach is two-folded: while a preventive strategy embeds virtual links into multiple substrate paths, a reactive strategy attempts to reallocate any capacity affected by an underlying DoS attack. Since the embedding problem is NP-Hard, we devise a Simulated Annealing meta-heuristic to solve it efficiently. Results show our solution can provide resilience to attacks at a lower cost. View full abstract