Toward multilayer disaggregated node telemetry and local decision making

A generic node agent supporting disaggregated node telemetry is presented. Data collection close to devices enable making local decisions, leveraging SDN controllers for network-wide operations. The agent is demonstrated in a BER-triggered transponder reconfiguration scenario.Peer ReviewedPostprint (published version

REACTION: Research and experimental assessment of control plane architectures for in-operation flexgrid network re-optimization

CONNECT: The magazine from the GÉANT community. Issue 18, 2015.The REACTION project proposes, designs, and validates flexi-grid elastic optical networks enabling software-controlled high-rate transmissions. In this paper, the main project objectives are reported, together with a brief summary on two main REACTION studies.Postprint (published version

Autonomic disaggregated multilayer networking

Focused on reducing capital expenditures by opening the data plane to multiple vendors without impacting performance, node disaggregation is attracting the interest of network operators. Although the software-defined networking (SDN) paradigm is key for the control of such networks, the increased complexity of multilayer networks strictly requires monitoring/telemetry and data analytics capabilities to assist in creating and operating self-managed (autonomic) networks. Such autonomicity greatly reduces operational expenditures, while improving network performance. In this context, a monitoring and data analytics (MDA) architecture consisting of centralized data storage with data analytics capabilities, together with a generic node agent for monitoring/telemetry supporting disaggregation, is presented. A YANG data model that allows one to clearly separate responsibilities for monitoring configuration from node configuration is also proposed. The MDA architecture and YANG data models are experimentally demonstrated through three different use cases: i) virtual link creation supported by an optical connection, where monitoring is automatically activated; ii) multilayer self-configuration after bit error rate (BER) degradation detection, where a modulation format adaptation is recommended for the SDN controller to minimize errors (this entails reducing the capacity of both the virtual link and supported multiprotocol label switching-transport profile (MPLS-TP) paths); and iii) optical layer selfhealing, including failure localization at the optical layer to find the cause of BER degradation. A combination of active and passive monitoring procedures allows one to localize the cause of the failure, leading to lightpath rerouting recommendations toward the SDN controller avoiding the failing element(s).Peer ReviewedPostprint (author's final draft

CASTOR: An architecture to bring cognition to transport networks

CASTOR architecture to enable cognitive networking is demonstrated. Extended nodes make local decisions, whilst a centralized system beside the network controller makes network-wide decisions. Interaction with ONOS, Net2Plan, and passive monitoring devices is exhibited.Peer ReviewedPostprint (published version

Dynamic core VNT adaptability based on predictive metro-flow traffic models

© 2017 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.MPLS-over-optical virtual network topologies (VNTs) can be adapted to near-future traffic matrices based on predictive models that are estimated by applying data analytics on monitored origin-destination (OD) traffic. However, the deployment of independent SDN controllers for core and metro segments can bring large inefficiencies to this core network reconfiguration based on traffic prediction when traffic flows from metro areas are rerouted to different ingress nodes in the core. In such cases, OD traffic patterns in the core might severely change, thus affecting the quality of the predictive OD models. New traffic model re-estimation usually takes a long time, during which no predictive capabilities are available for the network operator. To alleviate this problem, we propose to extend data analytics to metro networks to obtain predictive models for the metro flows; by knowing how these flows are aggregated into OD pairs in the core, we can also aggregate their predictive models, thus accurately predicting OD traffic and therefore enabling core VNT reconfiguration. To obtain quality metro-flow models, we propose an estimation algorithmthat processes monitored data and returns a predictive model. In addition, a flow controller is proposed for the control architecture to allow metro and core controllers to exchange metro-flow model information. The proposed model aggregation is evaluated through exhaustive simulation, and eventually experimentally assessed together with the flow controller in a testbed connecting premises in CNIT (Pisa, Italy) and UPC (Barcelona, Spain).Peer ReviewedPostprint (author's final draft

First experimental demonstration of ABNO-driven in-operation flexgrid network re-optimization

The after failure repair optimization problem is used to experimentally validate in-operation planning using the ABNO architecture to control a flexgrid optical network. A back-end PCE is used to solve this computationally-intensive planning problem.Postprint (published version

First experimental assessment of ABNO-driven in-operation flexgrid network re-optimization

Traffic affected by link failures can be recovered using path restoration schemes. In dynamically operated networks provided with a control plane, restoration algorithms run in a centralized element, such as the path computation element (PCE). To increase traffic restorability in flexgrid networks, multiple paths, subconnections, can be used to restore every single affected connection. However, the multipath restoration scheme might result in a poor resource utilization entailing a lesser grade of service. In-operation network planning algorithms can be used to mitigate this problem once the failed link is repaired; we propose solving the so-called multipath after failure repair optimization problem (MP-AFRO) to reduce subconnections count by aggregating those belonging to the same original connection and rerouting the resulting connection to release spectral resources. The MP-AFRO problem is modeled using a mixed integer linear program formulation. In view of the complexity of the model and the limited time to solve the problem, we propose a heuristic algorithm that provides a good tradeoff between complexity and optimality. The performance on the MP-AFRO heuristic is firstly validated by simulation. Next, the heuristic algorithm is deployed inside an in-operation planning tool in the form of back-end PCE (bPCE) inside the application-based network operations architecture controlling a network; the bPCE is connected to the centralized active stateful PCE. MP-AFRO is experimentally demonstrated using a distributed field trial test-bed connecting the premises of Telefonica (Madrid), CNIT (Pisa), and UPC (Barcelona).Peer ReviewedPostprint (author’s final draft

A control and management architecture supporting autonomic NFV services

The proposed control, orchestration and management (COM) architecture is presented from a high-level point of view; it enables the dynamic provisioning of services such as network data connectivity or generic network slicing instances based on virtual network functions (VNF). The COM is based on Software Defined Networking (SDN) principles and is hierarchical, with a dedicated controller per technology domain. Along with the SDN control plane for the provisioning of connectivity, an ETSI NFV management and orchestration system is responsible for the instantiation of Network Services, understood in this context as interconnected VNFs. A key, novel component of the COM architecture is the monitoring and data analytics (MDA) system, able to collect monitoring data from the network, datacenters and applications which outputs can be used to proactively reconfigure resources thus adapting to future conditions, like load or degradations. To illustrate the COM architecture, a use case of a Content Delivery Network service taking advantage of the MDA ability to collect and deliver monitoring data is experimentally demonstrated.Peer ReviewedPostprint (author's final draft

Accesibilidad a medicamentos oncológicos. Análisis comparativo según jurisdicción de residencia de la población de cobertura estatal, abordaje cuantitativo y cualitativo. Argentina 2006-2012

Introducción: considerando la importancia creciente del cáncer en la carga de enfermedad, resulta relevante estudiar la accesibilidad a medicamentos oncológicos. Objetivo: Analizar los niveles de utilización y equidad en la población con cobertura estatal en provincias y departamentos, las percepciones de pacientes y personal del sistema de salud sobre la accesibilidad, y las relaciones explicativas entre ambos análisis. Métodos: diseño poblacional retrospectivo, cuantitativo y cualitativo; el indicador de acceso es la tasa de uso, y el de equidad el cociente entre tasas extremas de departamentos. La muestra: Córdoba, Neuquén, Misiones, Tucumán, Mendoza y el Área Metropolitana Buenos Aires. Se entrevistaron informantes de niveles gerenciales, operativos, y pacientes. Resultados: en lo cuantitativo se reveló heterogeneidad en el uso y equidad: la comparación entre provincias de niveles extremos muestra a Mendoza con una combinación de uso/equidad once veces mayor que Misiones. También, asimetrías en el nivel de utilización por departamentos, de todas las provincias estudiadas. En lo cualitativo, se manifiesta un fuerte interés de los Estados provinciales en mejorar la provisión de servicios. Se expresaron problemas en la adquisición (por procesos contables lentos), en la provisión (por el lugar de entrega del medicamento) y en la administración (por insuficiencia de estructura, RRHH y equipo), que afectan la accesibilidad. Se percibe que algunos de estos problemas pueden resolverse con mayor integración de las redes pública y privada. Los pacientes destacan positivamente la cobertura que reciben, pero también revelan inconvenientes con los turnos de administración. Conclusiones: existen asimetrías del uso entre provincias y departamentos que constituyen inequidades. Es necesaria mayor integración público-privada. Los mecanismos de compra poco ágiles, la logística de provisión de medicamentos y los déficits de RRHH y equipo son problemas a resolver

Experimental Demonstration of Multivendor and Multidomain EON With Data and Control Interoperability Over a Pan-European Test Bed

The operation of multidomain and multivendor EONs can be achieved by interoperable sliceable bandwidth variable transponders (S-BVTs), a GMPLS/BGP-LS-based control plane, and a planning tool. The control plane is extended to include the control of S-BVTs and elastic cross connects, which combine a large port-count fiber-switch (optical backplane) and bandwidth-variable wavelength-selective switches, enabling the end-to-end provisioning and recovery of network services. A multipartner testbed is built to demonstrate and validate the proposed end-to-end architecture. Interoperability among S-BVTs is experimentally tested between different implementations. In this case, transponders are configured using the proposed control plane. The achieved performance with hard-decision and soft-decision FECs using only the information distributed by the control plane is measured against the performance of the single-vendor implementation, where proprietary information is used, demonstrating error-free transmission up to 300 km.Peer ReviewedPostprint (author's final draft