Energy-aware routing in multiple domains software defined networks

The growing energy consumption of communication networks has attracted the attention of the networking researchers in the last decade. In this context, the new architecture of Software-Defined Networks (SDN) allows a flexible programmability, suitable for the power-consumption optimization problem. In this paper we address the issue of designing a novel distributed routing algorithm that optimizes the power consumption in large scale SDN with multiple domains. The solution proposed, called DEAR (Distributed Energy- Aware Routing), tackles the problem of minimizing the number of links that can be used to satisfy a given data traffic demand under performance constraints such as control traffic delay and link utilization. To this end, we present a complete formulation of the optimization problem that considers routing requirements for control and data plane communications. Simulation results confirm that the proposed solution enables the achievement of significant energy savings.Peer ReviewedPostprint (published version

Self-healing topology discovery protocol for software defined networks

“© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. http://ieeexplore.ieee.org/document/8319433/”This letter presents the design of a self-healing protocol for automatic discovery and maintenance of the network topology in Software Defined Networks (SDN). The proposed protocol integrates two enhanced features (i.e. layer 2 topology discovery and autonomic fault recovery) in a unified mechanism. This novel approach is validated through simulation experiments using OMNET++. Obtained results show that our protocol discovers and recovers the control topology efficiently in terms of time and message load over a wide range of generated networks.Peer ReviewedPostprint (author's final draft

Discovering the network topology: an efficient approach for SDN

Network topology is a physical description of the overall resources in the network. Collecting this information using efficient mechanisms becomes a critical task for important network functions such as routing, network management, quality of service (QoS), among many others. Recent technologies like Software-Defined Networks (SDN) have emerged as promising approaches for managing the next generation networks. In order to ensure a proficient topology discovery service in SDN, we propose a simple agents-based mechanism. This mechanism improves the overall efficiency of the topology discovery process. In this paper, an algorithm for a novel Topology Discovery Protocol (SD-TDP) is described. This protocol will be implemented in each switch through a software agent. Thus, this approach will provide a distributed solution to solve the problem of network topology discovery in a more simple and efficient way.Peer ReviewedPostprint (published version

Historia del Proyecto Gijón de Arqueología

Sin resume

Inscripción romana hallada en la muralla de Gijón: una nueva "gens" entre los astures transmontanos

Presentamos en este articulo el estudio de una inscripción procedente de la muralla tardorromana de Gijón. Se trata de un documento de gran valor tanto por el lugar del hallazgo como por el contenido del texto donde se cita una nueva "gens" en Asturias

La intimidad personal: infinitud, misterio y morada

9 p.Dos de los aportes más significativos de la filosofía contemporánea son: el descubrimiento de la vida, como tema filosófico, debido, sobre todo, a Dilthey (1833-1911) y desarrollado en el ámbito hispánico por don José Ortega y Gasset y don Julián Marías, y el tema de la persona, que aunque hunde sus raíces en la reflexión de los padres de la Iglesia y en Boecio (480-525), llega con Mounier y, sobre todo, con los cultivadores posteriores del personalismo a convertirse en un tema de capital importancia para la antropología filosófica, la ética y la bioética personalista comprometida rotundamente con la dignidad de la persona humana. Uno de los temas más profundos e interesantes que han estudiado los personalistas es el de la intimidad personal, al cual quiero referirme partiendo de los estudios antropológicos de Julián Marías y, tangencialmente, de Romano Guardini. El problema que nos proponemos explorar nos pone frente a la inconmensurabilidad de la realidad personal, de eso que Julián Marías llama el “arcano de la persona”, lo que significa que no es fácil conocerse a sí mismo, que eso que la persona es resulta elusivo o evasivo y hay que perseguirlo con persistencia, porque si no se indaga por esa mismidad en la que reside la persona puede permanecer oculta

Thermally-induced clumped isotope resetting in belemnite and optical calcites: Towards material-specific kinetics

The application of carbonate clumped isotope (Δ47) thermometry in deep-time is often limited by modification of the original temperature signal by thermal resetting. New modeling approaches to estimate the initial isotopic composition of partially reset calcites and maximal burial temperatures, however, open promising avenues in temperature reconstruction. Such approaches strongly depend on laboratory-derived kinetic parameters of calcite materials, which may differ in their microstructure, water content and distribution, and minor and trace element composition, and thus may have different resetting kinetics. The rostra of belemnites, an extinct group of mollusks with a wide temporal and spatial occurrence in the Mesozoic, have been extensively used for deep-time paleoclimate reconstructions using oxygen isotope geochemistry. Belemnites are also important targets for clumped isotope-based temperature reconstructions, but often are found to have reset Δ47 compositions. Here, we present results from heating experiments on belemnite rostral calcite and optical calcite and provide belemnite-specific kinetic parameters for clumped isotope resetting. We show that belemnite calcite is altered faster and at lower temperatures than optical calcite and all other calcites reported in previous studies. We suggest that fast initial resetting results from oxygen isotope exchange of belemnite calcite with internal skeletal water present as fluid inclusions or organic-derived water, a process completed within 2–4 min at the experimental temperatures used here. Extrapolation to geological timescales using different solid-state bond reordering models shows that belemnite calcite resetting starts at lower burial temperatures than brachiopod, spar, and optical calcites. This susceptibility to thermal resetting results in a measurable (+3 ◦C) increase of the apparent Δ47 temperature even under shallow to moderate burial conditions (i.e., 40–50 ◦C for 106–107 years timescales). Following the overprint to higher apparent Δ47 temperatures during burial, the belemnite Δ47 may further reequilibrate during exhumation resulting in a decrease of apparent Δ47 temperatures. Such “retrograde resetting” is similar to what is observed for carbonatites and marbles during cooling, and may cause underestimation of the thermal resetting a sample experienced during its geological history. Overall, our results demonstrate the importance of material-specific kinetic parameters and we urge caution when interpreting Δ47-derived temperatures of biogenic carbonates from deep-time archives.Swiss National Science Foundation project number 200021_169849AF from Juan de la Cierva Fellowship (IJC2019040065-I)Spanish Ministry of Science and InnovationEuropean Development Fund and the European Social FundThe European Commission, Horizon 2020 (ICECAP; grant no. 101024218)The Research Council of Norway Centre of Excellence funding schemeProject number 223272. EBSD data for the WA-CB-11 brachiopod provided by the authors of Henkes et al. (2014)US National Science Foundation (EAR-1226832

A multi-objective routing strategy for QoS and energy awareness in software-defined networks

“© © 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. http://ieeexplore.ieee.org/document/8013750/”Energy consumption is a key concern in the deployment and operation of current data networks, for which Software-Defined Networks (SDN) have become a promising alternative. Although several works have been proposed to improve the energy efficiency, these techniques may lead to performance degradations when QoS requirements are neglected. Inspired by this problem, this letter introduces a new routing strategy, jointly considering QoS requirements and energy awareness in SDN with in-band control traffic. To that end, we present a complete formulation of the optimization problem and implement a Multi- Objective Evolutionary Algorithm. Simulation results validate the performance improvement on critical network parameters.Peer ReviewedPostprint (published version