Two Efficient QoS-Based Approaches for a Resource Splitting Strategy across Multiple Cloud Providers

In this paper, we address the problem of com-putational and networking virtual resources embedding across multiple Infrastructure-as-a-Service (IaaS) providers. This issue, usually referred to as the Virtual Network Embedding (VNE) problem, requires two phases of operation in such a context: the multicloud virtual network requests (VNRs) splitting, followed by the intracloud VNR segments mapping. This paper focuses on the splitting phase problem, by proposing a splitting strategy based on two optimization approaches, with the objective of improving the performance and the quality of service (QoS) of resulting mapped VNR segments. An Integer Linear Program (ILP) is used to formalize our splitting strategy as a mathematical minimization problem with constraints. The ILP model is first solved with the exact approach. Subsequently, a metaheuristic approach based on the Tabu Search (TS) is proposed in order to find optimal or near-optimal solutions in polynomial solving time. The simulation results obtained show the efficiency of the proposed VNRs splitting approaches according to several performance criteria. Solution costs of the heuristic are on average close to the exact solution, with an average cost gap ranging from 0% to a maximum of 2.05%, performed in a highly reduced computing time. In comparison with other baseline approaches, the acceptance rate and the delay are improved by approximately 15%, while preventing QoS violations.