Ana Carolina Riekstin

GreenSDN: Bringing energy efficiency to an SDN emulation environment

A significant number of green, energy-saving network protocols have been invented in recent years in response to demand for reducing the amount of energy consumed by network infrastructure. In this paper, we report on the difficulties we encountered when building an SDN environment that could emulate energy saving protocols operating at different layers of the network. We propose solutions, based on the Mininet environment and the POX Openflow controller, that emulate the effects of three different energy saving protocols. Our approach is validated by comparing energy savings obtained by activating these protocols in an emulated network topology inspired by the Brazilian Research Network.

No more electrical infrastructure: towards fuel cell powered data centers

We consider the use of fuel cells for powering data centers, based on benefits in reliability, capital and operational costs, and reduced environmental emissions. Using fuel cells effectively in data centers introduces several challenges and we highlight key research questions for designing a fuel cell based data center power distribution system. We analyze a specific configuration in the design space to quantify the cost benefits for a large scale data center, for the most mature and commonly deployed fuel cell technology, achieving over 20% reduction in costs using conservative projections.

Orchestration of energy efficiency capabilities in networks

The energy demand for operating Information and Communication Technology (ICT) systems has been growing, implying in high operational costs and consequent increase of carbon emissions. Both in datacenters and telecom infrastructures, the networks represent a significant amount of energy spending. Given that, there is an increased demand for energy efficiency solutions, and several capabilities to save energy have been proposed. However, it is very difficult to orchestrate such energy efficiency capabilities, that is, coordinate or combine them in the same network, ensuring a conflict-free operation and choosing the best one for a given scenario, ensuring that a capability not suited to the current bandwidth utilization will not be applied and lead to congestion or packet loss. There is neither a way to do this taking business directives into account. In this regard, a method able to orchestrate different energy efficiency capabilities is proposed considering the possible combinations and conflicts among them, as well as the best option for a given workload and network characteristics. The business policies are refined down to the network level in order to bring high-level directives into the operation, and a Utility Function is used to combine energy efficiency and performance requirements. A Decision Tree able to determine what to do in each scenario is deployed in a Software Defined Network environment. The proposed method was validated with different experiments, testing the Utility Function, checking the extra savings when combining several capabilities, the decision tree interpolation and dynamicity aspects. The orchestration proved valid to solve the problem of finding the best combination for a given scenario, achieving additional savings due to the combination, besides ensuring a conflict-free operation. HighlightsA method able to orchestrate different energy efficiency capabilities is proposed.It considers the possible combinations and conflicts among the capabilities.It refines business policies to bring high-level directives into the operation.The method solves the problem of finding the best combination for a given scenario.And achieved additional savings, besides ensuring a conflict-free operation.

A Survey of Policy Refinement Methods as a Support for Sustainable Networks

Green sustainability-oriented features have become common in network nodes and protocols. Running a network in an energy-efficient way is an important concern of network operators and datacenter networks. The implementation and coordination of the myriad of existing network features poses a challenging task. The energy efficiency capabilities must be selected according to the network conditions and can be combined to increase energy savings. However, they can conflict if not orchestrated in a proper manner. Policy-Based Network Management is a well-known approach to addressing the complexity of network management tasks. In conjunction with a refinement process to translate high-level policies down to low-level policies, it can bring business directives to the network, including sustainability goals. In this survey, we identify the major characteristics of sustainability-oriented policies, as well as the requirements a policy refinement method for such type of policies has to fulfill, including energy efficiency capabilities orchestration. We then analyze existing policy refinement techniques and discuss the challenges on how they address or need to be modified in order to be applicable to sustainability-oriented policies.

Orchestration of Energy Efficiency Functionalities for a Sustainable Network Management

The energy demand for operating Information and Communication Technologies is growing, implying in high operational costs and consequent carbon emissions. Both in datacenters and in telecom infrastructures, the networks represent a significant amount of energy spending. This implies in an increased demand for energy efficiency, and several functionalities to save energy are being proposed. However, there is no proposal on how to coordinate or combine such energy efficiency functionalities in the same network, or choosing the best one for a given scenario. There is neither a way to do this using business directives, telling, for instance, the period of the day to apply such functionalities or the operational conditions (e.g. If the network usage is low). In this regard, we propose a method able to orchestrate different energy efficiency functionalities considering the possible combinations and conflicts among them, as well as the best option for a given workload and network characteristics, such as topology and power profiles of devices. The business policies are refined down to the network level in order to bring high-level directives into the operation. Our method operation is validated with an example which achieves near 50% of savings for the given scenario by combining two different energy efficiency functionalities.

A Survey on Metrics and Measurement Tools for Sustainable Distributed Cloud Networks

Energy efficiency and emissions awareness are core capabilities for sustainable and lower cost distributed cloud networks. In this context, metrics are fundamental for comparison and management purposes, along with the methods and tools which support such metrics’ capture and analysis. However, prior works on green metrics and tools have presented only a partial view, mainly as a result of the recent advances in green networking technologies. In this survey, we present an extensive study of metrics, methods, and tools to support sustainable operations in distributed cloud networks, with the aim of providing an end-to-end and up-to-date scenario to support current and coming research, as well as to analyze existing gaps.

Monitoring and measurement system for green operation of geographically distributed ICT services

Despite recent efforts and important results already achieved, the reduction of energy consumption and carbon emissions by Information and Communication Technologies is still far from the expected goals. As the annual growth in traffic is doubling every two years with more and more connections to the Internet, to be energy and carbon-aware it is paramount to implement a Monitoring and Measurement System which supports green strategies in a geographically distributed environment. Such an environment has some specific challenges that must be taken into account, such as the WAN connection, security and latency concerns. On the other hand, it also provides opportunities to reduce operational costs and emissions, improve reliability and resources management etc. This work proposes a framework which is capable of supporting green metrics in network monitoring. The framework comprises temporally differentiated data on emission factors and provides ground information able to support different applications. We have implemented the framework in a nationwide testbed and our experiments show the framework is able to provide the ground information for customizable green metrics, like power/energy, traffic, and carbon equivalent emissions. This framework can be used as a support for a variety of applications which depend on energy and emissions metrics.

Sustainability Information Model for Energy Efficiency Policies

The need to manage the energy consumption of network infrastructure has been addressed by a significant body of work in recent years. In general, energy management capabilities were developed independently and optimized for particular network layers and node features. The interaction between multiple such green capabilities when deployed simultaneously, as well as potential interactions with other existing functionality such as quality of service functions, need to be managed transparently by the operators. We developed SLIM, the SustainabiLity Information Model for Energy Efficiency Policies, as an addon to the IETF Policy Core Information Model Extension to allow unifying the management of green capabilities throughout the network. We illustrate the flexibility of our approach by presenting a use case and describing an energy management system where SLIM was used.

A demonstration of energy efficiency capabilities orchestration in networks

Various energy efficiency network capabilities have been proposed in recent years in response to the demand of reducing the amount of energy consumed by the network infrastructure. In this regard, we demonstrate SOS, a method able to orchestrate different energy efficiency capabilities considering the possible combinations and conflicts among them, as well as the best option for a given bandwidth utilization and network characteristics, such as topology and power profiles of devices. The method was tested on GreenSDN, a testbed based on the Mininet environment and the POX controller, which emulates the effects of different energy efficiency capabilities. During the demonstration, we will show the energy efficiency achieved by the orchestration method, highlighting the additional savings due to capabilities orchestration, and, at the same time, considering performance constraints and different policies.

Automated refinement of sustainability-oriented policies for a sustainable network management

Sustainable networks management represents a significant opportunity for reducing energy consumption among Information and Communication Technologies. Policy Based Network Management (PBNM) is one of the key approaches to bring sustainability to networks. However, despite its poten-tial, PBNM is not yet widely commercially used. The widespread use depends on an automated policies refinement process in order to translate high-level policies into machine-readable policies able to put the business strategies into practice. This work aims at proposing an automated sustainability-oriented policies refinement method, as well as an architecture and a prototype to a sustainable network management.