Connectivity-aware Virtual Network Embedding

The problem of ensuring virtual network (VN) connectivity in presence of multiple link failures in the substrate network (SN) is not well investigated in Network Virtualization (NV) literature. We name this problem as Connectivity-aware Virtual Network Embedding (CoViNE). Solving CoViNE will enable a VN operator to perform failure recovery without depending on the SN provider, similar to the IP restoration mechanisms in IPover- WDM networks. There are two steps in solving CoViNE: i) finding the virtual links that should be embedded disjointly, and ii) finding a substrate resource efficient embedding that ensures the virtual link disjointness constraint. We present two solutions to the CoViNE problem. The first solution uses a heuristic to compute the disjointness constraint, while an optimization model is used for VN embedding. The second solution, in contrast, uses heuristic for both the steps, and thus can solve larger instances of the problem. We compare our solutions with a cut set based approach that ensures VN connectivity for a single substrate link failure. Evaluation results show that our heuristics allocate similar to 15% extra resources on average compared to the cut set based optimal solution, and executes two to three orders of magnitude faster on the same problem instances.