Abstract-In this paper we propose energy efficient design and operation of infrastructures incorporating integrated optical network and IT resources. For the first time we quantify significant energy savings of a complete solution jointly optimizing the allocation and provisioning of both network and IT resources. Our approach involves virtualization of the infrastructure resources and it is proposed and developed in the framework of the European project GEYSERS -Generalised Architecture for Dynamic Infrastructure Services.

This paper studies the impact of node degree distribution to availability and capital and deployment expenditure of optical WDM transport networks. Three structured degree-3 graphs with fair node degree distribution are proposed in this context. Using a realistic network optimization framework based on genetic algorithms, we evaluate the performance of structured topologies and compare it against a practical topology (NSFNET). The results manifest that nodal degree fairness leads to increased availability compared to conventional topologies, while not incurring higher capital and deployment cost.

Abstract-Rising energy costs and climate change have led to an increased concern for energy-efficiency (EE). As Information and Communication Technology (ICT) is responsible for about 4% of total energy consumption worldwide, it is essential to devise policies aimed at reducing it. In this paper, we propose a routing and scheduling algorithm for a cloud architecture, which targets minimal total energy consumption by enabling switching off unused network and/or Information Technology (IT) resources, exploiting the cloud-specific anycast principle. A detailed energy model for the entire cloud infrastructure comprising wide area optical network and IT resources is provided. This model is used to make a single-step decision on which IT end points to use for a given request, including the routing of the network connection towards these end points. Our simulations quantitatively assess the EE algorithm's potential energy savings, but also assess the influence this may have on traditional Quality of Service parameters such as service blocking. Furthermore, we compare the one-step scheduling with traditional scheduling and routing schemes, which calculate the resource provisioning in a two-step approach (selecting first the destination IT end point, and subsequently using unicast routing towards it). We show that depending on the offered infrastructure load, our proposed onestep calculation considerably lowers the total energy consumption (reduction up to 50%) compared to the traditional iterative scheduling and routing, especially in low to medium load scenarios, without any significant increase in the service blocking.

Abstract-This paper is aiming at facilitating the energyefficient operation of an integrated optical network and IT infrastructure. In this context we propose an energy-efficient routing algorithm for provisioning of IT services that originate from specific source sites and which need to be executed by suitable IT resources (e.g. data centers). The routing approach followed is anycast, since the requirement for the IT services is the delivery of results, while the exact location of the execution of the job can be freely chosen. In this scenario, energy efficiency is achieved by identifying the least energy consuming IT and network resources required to support the services, enabling the switching off of any unused network and IT resources. Our results show significant energy savings that can reach up to 55% compared to energy-unaware schemes, depending on the granularity with which a data center is able to switch on/off servers.

This paper presents a detailed study of planning virtual infrastructures (VIs) over a physical infrastructure comprising integrated optical network and data center resources with the aim of enabling sharing of physical resources among several virtual operators and services. Through the planning process, the VI topology and virtual resources are identified and mapped to the physical resources. Our study assumes a practical VI demand model without any in advance global knowledge of the VI requests that are handled sequentially. Through detailed integer linear program modeling, two objective functions-one that minimizes the overall power consumption of the infrastructure and one that minimizes the wavelength utilization-are compared. Both are evaluated for the virtual wavelength path and wavelength path optical network architectures. The first objective results in power consumption savings and the two optical network architectures provide similar performances. However, the trend changes for higher load values, due to the inefficient wavelength utilization that the first objective leads to. Finally, we compare the virtual infrastructures created by the two objectives through online traffic provisioning simulations. The objective minimizing wavelength utilization results in VIs suffering higher request blocking compared to the VIs created by the objective minimizing the overall power consumption.