Control de tráfico en el data center : Un enfoque experimental

Los centros de datos de escala masiva (MSDC, por sus siglas en ingles) se han convertido en un componente clave de la arquitectura de Internet. Con escalas de hasta cientos de miles de servidores, transportar tráfico dentro de estas infraestructuras requiere recursos de conectividad mucho mayores que en las redes de tránsito tradicionales de Internet. Usualmente, los MSCD utilizan topologías de tipo fat-tree, que brindan diversidad de caminos (o rutas múltiples) y un ancho de banda de bisección constante entre servidores. Para explotar las potenciales ventajas de estas topologías, se necesitan protocolos de enrutamiento específicos, con soporte para rutas múltiples y con baja carga de mensajería del plano de control. Estas infraestructuras tienen un alto costo, y por tanto, no es posible utilizarlas para experimentar con nuevos protocolos. Por esta razón, se necesitan entornos de emulación/simulación escalables y realistas que permitan experimentar emulando o simulando el comportamiento de estas grandes infraestructuras. En este trabajo, se revisaron y desarrollaron distintos ambientes de experimentación, tanto de un único host como distribuidos, que permiten analizar las ventajas y desventajas de las diferentes soluciones. Además, centrados en el Border Gateway Protocol (BGP), se ejecutó un conjunto de experimentos del plano de control sobre topologías fat-tree en entornos simulados y emulados. La validación de los resultados experimentales se complementó con un análisis teórico del comportamiento de BGP sobre un conjunto de escenarios seleccionados. Estos resultados experimentales y teóricos, así como la evaluación y desarrollo de los ambientes de experimentación, fueron oportunamente difundidos a la comunidad científica por medio de publicaciones científicas referadas. Todas los desarrollos de los entornos de experimentación realizados en el marco de este trabajo están disponibles y son reproducibles.Massive Scale Data Centers (MSDC) have become a key component of nowadays content-centric Internet architecture. With scales up to hundred thousands servers, conveying traffic inside these infrastructures requires much larger connectivity resources than traditional broadband Internet transit networks. MSCD uses fat-tree type topologies, which ensure multipath connectivity and constant bisection bandwidth between servers. To properly use the potential advantages of these topologies, specific routing protocols are needed, with multipath support and low control messaging load. These infrastructures are hugely expensive, and therefore, it is not possible to use them to experiment with new protocols. This rises the need for scalable and realistic emulation/simulation environments. In this work, we reviewed and developed several experimental environments, both single-host and distributed, analyzing the benefits and drawbacks of the different solutions. Also, focused on the Border Gateway Protocol (BGP), we ran a comprehensive set of control plane experiments over fat-tree topologies in both simulated and emulated environments. The validation of the experimental results was complemented with a theoretical analysis of BGP behavior over selected scenarios. These experimental and theoretical results, as well as the evaluation and development of the experimental environments, were opportunely disseminated to the scientic community through peer-reviewed scientic publications. All the development of the experimentation environments are available and can be reproduced.Beca de maestría nacional ANII

Experimenting with routing protocols in the data center : An ns-3 simulation approach

Massive scale data centers (MSDC) have become a key component of current content-centric Internet architecture. With scales of up to hundreds of thousands servers, conveying traffic inside these infrastructures requires much greater connectivity resources than traditional broadband Internet transit networks. MSDCs use Fat-Tree type topologies, which ensure multipath connectivity and constant bisection bandwidth between servers. To properly use the potential advantages of these topologies, specific routing protocols are needed, with multipath support and low control messaging load. These infrastructures are enormously expensive, and therefore it is not possible to use them to experiment with new protocols; that is why scalable and realistic emulation/simulation environments are needed. Based on previous experiences, in this paper we present extensions to the ns-3 network simulator that allow executing the Free Range Routing (FRR) protocol suite, which support some of the specific MSDC routing protocols. Focused on the Border Gateway Protocol (BGP), we run a comprehensive set of control plane experiments over Fat-Tree topologies, achieving competitive scalability running on a single-host environment, which demonstrates that the modified ns-3 simulator can be effectively used for experimenting in the MSDC. Moreover, the validation was complemented with a theoretical analysis of BGP behavior over selected scenarios. The whole project is available to the community and fully reproducible

A new device laboratory: Experimental validation

Postprint (published version

Experimentation Environments for Data Center Routing Protocols: A Comprehensive Review

The Internet architecture has been undergoing a significant refactoring, where the past preeminence of transit providers has been replaced by content providers, which have a ubiquitous presence throughout the world, seeking to improve the user experience, bringing content closer to its final recipients. This restructuring is materialized in the emergence of Massive Scale Data Centers (MSDC) worldwide, which allows the implementation of the Cloud Computing concept. MSDC usually deploy Fat-Tree topologies, with constant bisection bandwidth among servers and multi-path routing. To take full advantage of such characteristics, specific routing protocols are needed. Multi-path routing also calls for revision of transport protocols and forwarding policies, also affected by specific MSDC applications’ traffic characteristics. Experimenting over these infrastructures is prohibitively expensive, and therefore, scalable and realistic experimentation environments are needed to research and test solutions for MSDC. In this paper, we review several environments, both single-host and distributed, which permit analyzing the pros and cons of different solutions

Rotary inverted pendulum with magnetically external perturbations as a source of the pendulum’s base navigation commands

The main objective of this paper is to drive a rotary inverted pendulum by following a desired navigation instruction. This navigation is commanded by the user through a new electromagnetic device which is allowed to perturb the pendulum from its upright position. This apparatus consists of an electronic magnetic driving circuit to introduce commands and realized via two operated magnetic coils. So, the external programmed magnetic perturbation can be seen as external commandments. Therefore, the control problem statement is solved via a modified regulation control implementation, to maintain the pendulum on its upright position and giving free manipulation of the base of the rotary inverted pendulum. Hence, by using the corresponding H8-linear matrix inequality technique, a static state controller is designed and tested experimentally so supporting our findings.Peer Reviewe