Planificación de redes ópticas wavelength-routing con demanda dinámica de tráfico

Escueal Técnica Superior de Ingeniería de Telecomunicació

Planificación de Redes Troncales de Conmutación Óptica Transparente

El continuo crecimiento de Internet está obligando a buscar nuevos medios para proporcionar mayores capacidades de transmisión en las redes de comunicaciones. Las redes troncales de conmutación óptica transparente representan una respuesta factible a corto y medio plazo para lograr este fin. Por tanto, la planificación de estas redes, buscando un diseño que minimice los costes de la red, tanto OPEX como CAPEX, adquiere una especial relevancia. Este articulo pretende hacer una breve exposición de los conceptos básicos de este tipo de planificación. Para concluir se muestra un caso de estudio, donde se compararan las principales metodologías de planificación de redes ópticas transparentes

Virtual topology design and flow routing in optical networks under multi-hour traffic demand

This paper addresses the problem of finding a static virtual topology design and flow routing in transparent optical WDM networks under a time-varying (multi-hour) traffic demand. Four variants of the problem are considered, using fixed or dynamically adaptable (i.e., variable) flow routing, which can be splittable or unsplittable. Our main objective is to minimize the number of transceivers needed which make up for the main network cost. We formulate the problem variants as exact ILPs (Integer Linear Programs) and MILPs (Mixed ILPs). For larger problem instances, we also propose a family of heuristics based on the concept of domination between traffic matrices. This concept provides the theoretical foundations for a set of techniques proposed to reduce the problem complexity. We present a lower bound to the network cost for the case in which the virtual topology could be dynamically reconfigured along time. This allows us to assess the limit on the maximum possible benefit that could be achieved by using optical reconfigurable equipment. Extensive tests have been conducted, using both synthetically generated and real-traced traffic demands. In the cases studied, results show that combining variable routing with splittable flows obtains a significant, although moderate, cost reduction. The maximum cost reduction achievable with reconfigurable virtual topologies was shown to be negligible compared to the static case in medium and high loads.The work described in this paper was carried out with the support of the BONE project (“Building the Future Optical Network in Europe”); a Network of Excellence funded by the European Commission through the 7th ICT-Framework Program. This research has been partially supported by the projects from the Spanish Ministry Of Education TEC2007-67966-01/TCM CON-PARTE-1, and TEC2008-02552-E, and it is also developed in the framework of the projects from Fundación Seneca (Regional Agency of Science and Technology of Region of Murcia ) 00002/CS/08 (FORMA) and "Programa de Ayudas a Grupos de Excelencia de la Región. de Murcia”, F. Séneca (Plan Regional de Ciencia y Tecnología 2007/2010)."

Scheduled virtual topology design under periodic traffic in transparent optical networks

This paper investigates offline planning and scheduling in transparent optical networks for a given periodic traffic demand. The main objective is to minimize the number of transceivers needed which make up for the main network cost. We call this problem ldquoScheduled Virtual Topology Designrdquo and consider two variants: non-reconfigurable and reconfigurable equipment. We formulate both problems as exact MILPs (Mixed Integer Linear Programs). Due to their high complexity, we propose a more scalable tabu search heuristic approach, in conjunction with smaller MILP formulations for the associated subproblems. The main motivation of our research efforts is to assess the benefits of using reconfigurable equipment, realized as a reduction in the number of required transceivers. Our results show that the achieved reductions are not very significant, except for cases with large network loads and high traffic variability.The work described in this paper was carried out with the support of the BONE-project ("Building the Future Optical Network in Europe”), a Network of Excellence funded by the European Commission through the 7th ICTFramework Programme, support of the MEC Spanish project TEC2007- 67966-01/TCM CONPARTE-1 and developed in the framework of "Programa de Ayudas a Grupos de Excelencia de la Región de Murcia, de la Fundación Séneca (Plan Regional de Ciencia y Tecnología 2007/2010).

Algorithms for virtual topology reconfiguration under multi-hour traffic using Lagrangian relaxation and Tabu Search approaches

Periodic reconfiguration of the virtual topology in transparent optical networks has been recently investigated as a mechanism to more efficiently adapt the network to predictable periodic traffic variations along the day or week. The scheduling of periodic reconfigurations should consider the trade-off between a lower network cost obtained through better resource allocation, and the undesired traffic disruptions that these reconfigurations may cause. This paper presents and compares two algorithms for planning virtual topology reconfiguration suitable for exploring this trade-off. The first is based on a Lagrangian relaxation of the planning problem, and the second is based on a Tabu Search meta-heuristic. The merits of both algorithms are compared

MatPlanWDM: An Educational Open-source Tool for Communication Networks Planning Courses. Póster

[SPA]Este póster presenta la herramienta MatPlanWDM y su aplicación como recurso docente en asignaturas de Planificación de Redes de Comunicaciones en la Universidad Politécnica de Cartagena (España). MatPlanWDM está implementada como una toolbox de MATLAB junto con una interfaz gráfica. Se utiliza para la planificación de redes ópticas Wavelength-Routed (WR) Wavelength Division Multiplexing (WDM). La herramienta incluye un algoritmo heurístico y dos solvers para obtener la planificación óptima en topologías pequeñas. MatPlanWDM está diseñada para ayudar al estudiante en la definición y evaluación comparativa de sus propios algoritmos de planificación. El software puede ser descargado gratuitamente desde la página Web de MatPlanWDM. [ENG]This poster presents MatPlanWDM tool and its application as an educational resource in Communication Networks Planning courses in the Technical University of Cartagena (Spain). MatPlanWDM is implemented as a MATLAB toolbox, together with a Graphical User Interface. It is devoted to the network planning of Wavelength- Routed (WR) optical Wavelength Division Multiplexing (WDM) networks. The tool includes a built-in heuristic algorithm and two solvers to obtain the optimum planning solution in small topologies. MatPlanWDM is designed to assist the student in the definition and comparative evaluation of its original network planning algorithms. The software can be publicly downloaded at the MatPlanWDM site.Campus Mare Nostrum, Universidad Politécnica de Cartagena, Universidad de Murcia, Región de Murci

MILP formulations for scheduling lightpaths under periodic traffic

This paper addresses offline virtual topology design in transparent optical networks under given periodic traffic. We call this planning problem ldquoScheduled Virtual Topology Designrdquo. Two problem variants are considered: for a network based on non-reconfigurable equipment and for a network based on reconfigurable equipment. Two MILP (Mixed Integer Linear Program) formulations are proposed, one for each alternative. The number of transceivers in the network is the selected cost figure to minimize. Tests are performed to evaluate the benefits of using reconfigurable equipment under different traffic conditions and network sizes. The reduction in the number of transceivers obtained by allowing temporal variations in the virtual topology seems low in all cases, indicating that using reconfigurable equipment may not be cost-effective for periodic traffic.The work described in this paper was carried out with the support of the BONE-project ("Building the Future Optical Network in Europe”), a Network of Excellence funded by the European Commission through the 7th ICT-Framework Programme, the support of the MEC Spanish project TEC2007-67966-01/TCM CONPARTE-1, the support of the Fundación Séneca project FORMA 00002/CS/08, and developed in the framework of "Programa de Ayudas a Grupos de Excelencia de la Región de Murcia, de la Fundación Séneca (Plan Regional de Ciencia y Tecnología 2007/2010)”

Emotional Strengths and Difficulties in Italian Adolescents: Analysis of Adaptation through the SDQ

An adolescent’s knowledge of him/herself (positive aspects and weaknesses) is shaped by interactions with external and internal factors, including the family context and the educational environment. The assessment of this knowledge serves to construct the concept of self-esteem. The main objective of the present study was to examine the prevalence of self-reported emotional and behavioral symptoms in a representative sample of Italian adolescents and their relationship with gender and age, using Goodman’s Strengths and Difficulties Questionnaire (SDQ). A total of 440 adolescents (49.8% female) aged 15–18 years from the southern Italy region participated. The results show the prevalence of emotional and behavioral symptoms in the analyzed sample. Gender differences were also found in the variables under study. In conclusion, the SDQ test is offered as an agile, simplified, and effective tool, to be proposed to all formative agents who are concerned with the interest and care not only of young people, but also of the future of socio-political realities

Offline Iipairment aware RWA algorithms for cross-layer planning of optical networks

Transparent optical networks are the enabling infrastructure for converged multi-granular networks in the future Internet. The cross-layer planning of these networks considers physical impairments in the network layer design. This is complicated by the diversity of modulation formats, transmission rates, amplification and compensation equipments, or deployed fiber links. Thereby, the concept of quality of transmission (QoT) attempts to embrace the effects of the physical layer impairments, to introduce them in a multi-criterium optimization and planning process. This paper contributes in this field by the proposal and comparative evaluation of two novel offline impairment aware planning algorithms for transparent optical networks, which share a common QoT evaluation function. The first algorithm is based on an iterative global search driven by a set of binary integer linear programming formulations. Heuristic techniques are included to limit the binary programming complexity. The second algorithm performs different pre-orderings of the lightpath demand, followed by a sequential processing of the lightpath demands. The performance and the scalability of both approaches are investigated. Results reveal great scalability properties of the global search algorithm, and a performance similar to or better than the sequential schemes.The work described in this paper was carried out with the support of the BONE project (“Building the Future Optical Network in Europe”); a Network of Excellence, and the DICONET project (“Dynamic Impairment Constraint Networking for Transparent Mesh Networks”), both funded by the European Commission through the 7th ICTFramework Program. This research has been partially supported by the MEC project TEC2007- 67966-01/TCM CON-PARTE-1, and it is also developed in the framework of "Programa de Ayudas a Grupos de Excelencia de la R. de Murcia, F. Séneca"

Informe elaborado desde la Plataforma Temática Interdisciplinar Salud Global / Global Health del CSIC

Victoria Moreno, Vicepresidencia Adjunta de Áreas Científico-Técnicas, coordinadora del informe.Newsletter PTI Salud Global / Global Health Cov19. Píldoras: https://cutt.ly/sgmXa2vLa pandemia COVID-19, causada por un nuevo coronavirus, el SARS-CoV-2, se ha convertido en pocos meses en una amenaza para la humanidad, desencadenando la peor crisis sanitaria de este siglo. Más de veinte millones de personas han sido ya infectadas por el virus y más de 700.000 han muerto en todo el mundo como resultado de esta infección. En el ámbito de la investigación, esta pandemia ha obligado a un esfuerzo extraordinario de colaboración nacional e internacional. El Consejo Superior de Investigaciones Científicas (CSIC) ha canalizado este esfuerzo creando una Plataforma Temática Interdisciplinar (PTI) denominada Salud Global/Global Health, con el objetivo de encontrar soluciones a corto, medio y largo plazo, para reducir el impacto de esta pandemia en nuestra sociedad. La plataforma ha movilizado y coordina a más de 300 grupos de investigación de más de 90 centros del CSIC, en seis grupos de trabajo temáticos, que tratan de cubrir con un enfoque interdisciplinar todos los aspectos de la pandemia: Prevención, Enfermedad, Contención y Diagnóstico, Tratamiento y Vacunas, Impacto social, y Comunicación. Este informe, elaborado desde esta plataforma, presenta por una parte el conocimiento actual a nivel global que tenemos en estas temáticas sobre la pandemia, basado en las publicaciones e informes científicos y técnicos publicados hasta el momento, y en paralelo los proyectos de investigación en desarrollo por los grupos de investigación del CSIC. Gracias al apoyo a través de convocatorias y donaciones directas de entidades públicas y privadas, y también de particulares, a quienes desde aquí queremos agradecer la confianza depositada, el CSIC ha puesto en marcha más de 80 proyectos y acciones de investigación, que abarcan desde el estudio del genoma del virus, la genética de los pacientes, su respuesta inmune, la gravedad de la infección, hasta el desarrollo de antivirales, vacunas, sistemas de diagnóstico, de monitorización, de protección, de desinfección, etc. Nuestro conocimiento sobre la pandemia y su evolución está cambiando rápidamente, y por ello una parte importante de los contenidos de este informe deberán actualizarse, esperamos que tanto la investigación en el CSIC como a escala nacional y global logren que podamos describir en el futuro como estos avances han logrado que la pandemia quede controlada.Peer reviewe