An overlay mapping model for achieving enhanced QoS and resilience performance

In this paper, we investigate the issue of how to map an application request upon a substrate network in such a way that the selected hosting node and link sets can provide not only enhanced Quality-of-Service (QoS) but also resilience against potential substrate link failure(s). Different from previous works which only strive to solve this problem heuristically, this paper formulates it as an Integer Linear Program (ILP). In multi-layer networks, diversity of the working and backup paths is important because a single link failure in the lower layer can result in failures of all the upper-layer links that go through it. Thus, we further strengthen the proposed ILP model by incorporating the objective of finding effective backup paths during the application request mapping process. This is achieved by exploiting the substrate topology information. The effectiveness of the proposed ILP model is verified through extensive simulations. This novel ILP model is proved to perform significantly better in terms of QoS performance as compared to the heuristic solutions. Moreover, the proposed ILP model can provide diversified working and backup paths using few additional substrate nodes.