Hierarchical Approach for Efficient Virtual Network Embedding Based on Exact Subgraph Matching

The virtual network (VN) embedding problem is concerned with mapping the nodes and links of a VN request to a shared substrate network while maximizing some objective function such as maximizing profit or resource utilization. This mapping must satisfy specific node capacity and link bandwidth requirements. This paper presents a novel hierarchical approach for scalable VN embedding that achieves a balance between centralized schemes that have a network-wide view of available resources but represent a management bottleneck and scalable distributed ones that incur a high message overhead. The contribution of this work is two fold; we introduce a novel hierarchical substrate management framework that finds more than one candidate VN mapping in parallel, thus, increasing the chances of finding an optimal mapping. The second contribution is a novel VN mapping scheme that recasts the VN mapping problem as a subgraph matching one using modified graph-powers, and introduces a simple heuristic matching scheme to find an efficient VN mapping. In contrast to existing solutions, the proposed framework does not impose any limitations on the size or topology of the VN request, rather the search is tailored based on the VN size. Experimental results demonstrate the performance of the proposed scheme.