Virtual Network Embedding in Ring Optical Data Centers Using Markov Chain Probability Model

摘要

Cloud data centers nowadays play an important role in providing computing and network resources for online applications and services. Such applications obtain cloud resources by submitting resource requests in the form of virtual networks that are embedded in the cloud infrastructures, referred to as virtual network embedding (VNE). Developing an effective VNE algorithm is crucial since it affects the performance of data centers, such as rejection ratio, resource utilization, and revenue. The problem is much more challenging when considering ring optical data centers due to multiple issues: wavelength continuity constraint, wavelength selection, and physical path selection for a lightpath. In this paper, we first develop an optimization programming formulation, which is computationally prohibitive. We then develop a novel VNE algorithm that adopts the Web page ranking approach to evaluate the goodness of a top-of-the-rack (ToR)-based on its resources in correlation with that of other ToRs. We also develop efficient methods for wavelength and physical path selections for a lightpath dynamically created during the embedding. We evaluate the proposed algorithm through comprehensive simulations in comparing with the optimal results and baseline algorithms. The simulation results show that the proposed algorithm performs close to the optimal one. It significantly reduces the rejection ratio by at least 23 compared to the baseline algorithms, leading to an increase in revenue by at least 14.