Leveraging tenant flexibility in resource allocation for virtual networks

Virtual networks that allow tenants to explicitly specify their computing as well as networking resources are recently proposed to be better interfaces between cloud providers and tenants. Many virtual networks have time-varying resource demands, as evidenced in prior studies [1-3]. New opportunities emerge when such variation is exploited. In this paper, we design a novel resource demand model for tenants to flexibly trade off between application performance and cost, and propose a work-conserving allocation algorithm, WCA, for deploying virtual networks with time-varying resource demands. WCA places virtual nodes in a first-fit fashion, and places virtual links through path-splitting. In each physical node or link, by opportunistically sharing physical resources among multiple variable parts of resource demands, physical utilization can be improved, and more virtual networks can be deployed concurrently. Our evaluation results show that WCA achieves a 4% higher physical resource utilization and rejects 18% less virtual network requests than a state-of-the-art algorithm [4].