Virtualizing converged optical network and IT infrastructures: The benefits of dynamic virtual infrastructure re-planning

New emerging high performance and distributed applications require the interconnection of IT resources through high capacity and flexible networks. In this context, the FP7 GEYSERS project proposes on-demand provisioning of converged Virtual Infrastructures composed of IT and optical network resources, able to support the delivery of cloud services. Virtual Infrastructures must be specifically designed to support the required service loads. However, due to the unpredictable volume and nature of services, dynamic and on-demand re-planning of Virtual Infrastructures is required to allow the operators to support service requests that are not known in advance, while limiting over-provisioning and optimizing the global infrastructure utilization. This paper investigates the business and technical motivations for infrastructure re-planning, and presents different re-planning models in terms of timescales, involved resources and procedure automation. A dedicated cross-layer architectural solution is proposed, describing its implementation within the GEYSERS prototype. Simulation studies are provided to compare the performance of static planning to that of dynamic re-planning, showing the re-planning benefits in terms of resource utilization and energy consumption. Finally, the paper presents the experimental validation of the prototype over the GEYSERS test-bed.