A Virtualization Layer Approach to Survivability

Network virtualization facilitates sharing and efficient utilization of computing and bandwidth resources of an underlying substrate network. As network virtualization becomes popular, it is important to efficiently map a virtual infrastructure (VI) onto a substrate network, such that the survivability of the former can be guaranteed against failures in the latter. In this paper, we study a virtualization layer approach to survivability, whereby the virtualization layer customizes a VI request with redundant nodes and links according to its reliability requirements and then passes limited information about the augmented VI to the physical layer, where the mapping of the augmented VI takes place. More specifically, we develop a flexible scheme to enhance the original VI graph with K redundant nodes, in order to fight against an arbitrary substrate node failure. In addition, a scenario-based component group (SBCG) concept is proposed to describe resource sharing of enhanced VI requests at the physical layer. We also develop an efficient heuristic that takes advantage of the limited information on SBCG to reduce costs when mapping the enhanced VI to the substrate network. The efficiency of the proposed solution is compared using extensive simulation under various performance metrics. It is shown that the K-redundant-node scheme with SBCG information is more cost efficient than the existing 1-redundant-node solution.