Análisis de la Tecnología WDS y su Aplicaicón en el Diseño de Infraestructura de Red Inalámbrica en Ambiente Open Source. Caso Práctico: Fundación Desarrollo Solidario

Se diseñó e implementó una infraestructura de red inalámbrica utilizando tecnología Wireless Distribution System (WDS), con la finalidad de solucionar la problemática en cuanto a conectividad, movilidad, escalabilidad en la Fundación Desarrollo Solidario ubicada en la ciudad de Riobamba. Se utilizó 2 PCs Dell como puntos de acceso, a las que se agregó tarjetas pci inalámbricas con antenas omnidireccionales de ganancia 5 dbi, instalándoles sistema Mikrotik RouterOS en el cual se configuró WDS, utilizando modem Huawei para conexión y acceso a internet. Se configuró un servidor dhcp y samba en un equipo HP Proliant bajo sistema operativo CentOS, utilizando método inductivo, con Wi-Fi en equipos para red inalámbrica. Con WDS se logró interconectar inalámbricamente los puntos de acceso. Al implementar la red, se verificó que existe 100% de conectividad entre equipos; soporta tráfico estimado en un 3,43 Mbps entre correo electrónico, navegación en Internet, acceso a servidores con conexión simultánea para 26 usuarios de la Fundación; garantiza un correcto desempeño de aplicaciones; proporciona información en tiempo real en cualquier lugar dentro de la organización, solucionando en un 100% la problemática en cuanto a movilidad. Con referencia a escalabilidad, la red tiene capacidad de cambiar su tamaño o configuración para adaptarse a un mayor número de usuarios agregando un punto de acceso. Se recomienda al administrador de la red, realizar actividades de monitoreo, atención de fallas, configuración y seguridad para ayudar a mantener la operatividad de recursos y buen desempeño de la red

Evaluación comparativa del rendimiento de controladores SDN de código abierto

Software-defined Networking (SDN) constitutes a new era in the development of internetworking. The SDN paradigm splits the data plane from the control plane. It uses controller equipment, which is responsible for centrally managing several network devices simultaneously. This study analyzes three open-source controllers for SDN based on the OpenFlow protocol. Specifically, the performance of FloodLight, OpenDayLight (ODL), and Ryu controllers is evaluated in terms of latency, throughput, and scalability. In doing so, the Cbench tool is used in an emulated environment with Mininet. The results show that the Ryu controller presents the lowest performance in all the evaluated parameters; ODL provides lower latency and FloodLight higher throughput. Regarding scalability, we conclude that Floodlight can be used in small networks, whereas ODL can be used in dense networks. Furthermore, we evaluate their main characteristics, which must be considered for their choice prior to implementation and deployment.Las redes definidas por software (SDN) constituyen una nueva era en el diseño de la interconexión de redes. El paradigma SDN separa el plano de datos del plano de control. Para esto utiliza un equipo controlador, que se encarga de gestionar de forma centralizada varios dispositivos de red al mismo tiempo. Este estudio analiza tres controladores SDN de código abierto basados en el protocol OpenFlow. Específicamente, el rendimiento de los controladores FloodLight, OpenDayLight (ODL) y Ryu son evaluados en términos de latencia, throughput y escalabilidad. Para ello se utilizó la herramienta Cbench en un entorno emulado con Mininet. Los resultados muestran que el controlador presenta un menor rendimiento en todos los parámetros evaluados; ODL tiene una menor latencia y Floodlight un mayor throughput. En lo que tiene que ver a escalabilidad, se concluye que Floodlight es recomendable para redes pequeñas y ODL para redes densas. Además, evaluamos sus principales características, las cuales deben ser tomadas en cuenta para su elección antes de su implementación y despliegue

Performance Study and Enhancement of Access Barring for Massive Machine-Type Communications

[EN] Machine-type communications (MTC) is an emerging technology that boosts the development of the Internet of Things by providing ubiquitous connectivity and services. Cellular networks are an excellent choice for providing such hyper-connectivity thanks to their widely deployed infrastructure, among other features. However, dealing with a large number of connection requests is a primary challenge in the cellular-based MTC. Severe congestion episodes can occur when a large number of devices try to access the network almost simultaneously. Extended access barring (EAB) is a congestion control mechanism for the MTC that has been proposed by the 3GPP. In this paper, we carry out a thorough performance analysis of the EAB and show the limitations of its current specification. To overcome these limitations, we propose the two enhanced EAB schemes: the combined use of the EAB and access class barring, and the introduction of a congestion avoidance backoff after the barring status of a UE is switched to unbarred. It is shown through extensive simulations that our proposed solutions improve the key performance indicators. A high successful access probability can be achieved even in heavily congested scenarios, the access delay is shortened, and, most importantly, the number of required preamble retransmissions is reduced, which results in significant energy savings. Furthermore, we present an accurate congestion estimation method that solely relies on the information available at the base station. We show that this method permits a realistic and effective implementation of the EAB.This work was supported in part by the Ministerio de Ciencia, Innovacion y Universidades (MCIU), Agencia Estatal de Investigacion (AEI) y Fondo Europeo de Desarrollo Regional (FEDER), UE, under Grant PGC2018-094151-B-I00, and in part by the ITACA Institute under Grant Ayudas ITACA 2019Vidal Catalá, JR.; Tello-Oquendo, L.; Pla, V.; Guijarro, L. (2019). Performance Study and Enhancement of Access Barring for Massive Machine-Type Communications. IEEE Access. 7:63745-63759. https://doi.org/10.1109/ACCESS.2019.2917618S6374563759

Ataques Zero-day: Despliegue y evolución

In cybersecurity and computer science, the term “zero-day” is commonly related to troubles, threats, and hazards due to the lack of knowledge, experience, or misunderstanding. A zero-day attack is generally considered a new vulnerability with no defense; thus, the possible attack will have a highrisk probability, and a critical impact.  Unfortunately, only a few surveys on the topic are available that would help understand these threats, which are not enough to construct new solutions to detect, prevent, and mitigate them. In this paper, it is conducted a review of the zero-day attack, how to understand its real impact, and a few different accessible solutions nowadays. This study introduces a useful reference that provides researchers with knowledge to understand the current problem concerning zero- days attacks; hence they could develop solutions for facing them.En la ciberseguridad y la informática, el término "Zero-day" se relaciona comúnmente con problemas, amenazas y peligros, esto debido a la falta de conocimiento, experiencia o malentendidos relacionados. Un ataque de Zero-day se considera generalmente una nueva vulnerabilidad sin defensa; por lo tanto, el ataque consecuente tendrá una alta probabilidad de riesgo, y un impacto crítico. Lamentablemente, sólo unos pocos estudios están  disponibles  para  comprender  estas  amenazas, y no bastan para construir nuevas soluciones para detectar, prevenir y mitigar estas dificultades. En este artículo, se presenta una revisión del ataque Zero-day, enfocándose en comprender su impacto real y algunas soluciones accesibles  hoy  en  día. Este estudio presenta una referencia útil que proporciona a los investigadores conocimientos para comprender el problema actual relacionado con los ataques Zero-day. Este puede ser un punto de partida para desarrollar soluciones para combatir este problema

Software-Defined architecture for QoS-Aware IoT deployments in 5G systems

[EN] Internet of Things (IoT), a ubiquitous network of interconnected objects, harvests information from the environments, interacts with the physical world, and uses the existing Internet infrastructure to provide services for information transfer and emerging applications. However, the scalability and Internet access fundamentally challenge the realization of a wide range of IoT applications. Based on recent developments of 5G system architecture, namely SoftAir, this paper introduces a new software-defined platform that enables dynamic and flexible infrastructure for 5G IoT communication. A corresponding sum-rate analysis is also carried out via an optimization approach for efficient data transmissions. First, the SoftAir decouples control plane and data plane for a software-defined wireless architecture and enables effective coordination among remote radio heads (RRHs), equipped with millimeter-wave (mmWave) frontend, for IoT access. Next, by introducing an innovative design of software-defined gateways (SD-GWs) as local IoT controllers in SoftAir, the wide diversity of IoT applications and the heterogeneity of IoT devices are easily accommodated. These SD-GWs aggregate the traffic from heterogeneous IoT devices and perform protocol conversions between IoT networks and radio access networks. Moreover, a cross-domain optimization framework is proposed in this extended SoftAir architecture concerning both upstream and downstream communication, where the respective sum-rates are maximized and system-level constraints are guaranteed, including (i) quality-of-service requirements of IoT transmissions, (ii) total power limit of mmWave RRHs, and (iii) fronthaul network capacities. Simulation results validate the efficacy of our solutions, where the extended SoftAir solution surpasses existing IoT schemes in spectral efficiency and achieves optimal data rates for next-generation IoT communication. (C) 2019 Elsevier B.V. All rights reserved.This work was supported by the US National Science Foundation (NSF) under Grant No. 1547353. A part of this work was supported by the Harry C. Kelly Memorial Fund, AC21 Special Project Fund (SPF), NC State 2019-2020 Internationalization Seed Grants and 2019 Faculty Research and Professional Development (FRPD) Program. The work of V. Pla was supported by Grant PGC2018-094151-B-I00 (MCIU/AEI/FEDER, UE).Tello-Oquendo, L.; Lin, S.; Akyildiz, IF.; Pla, V. (2019). Software-Defined architecture for QoS-Aware IoT deployments in 5G systems. Ad Hoc Networks. 93:1-11. https://doi.org/10.1016/j.adhoc.2019.101911S1119

Performance analysis of wireless networks based on time-scale separation: A new iterative method

The complexity of modern communication networks makes the solution of the Markov chains that model their traffic dynamics, and therefore, the determination of their performance parameters, computationally costly. However, a common characteristic of these networks is that they manage multiple types of traffic flows operating at different time-scales. This time-scale separation can be exploited to substantially reduce the computational cost. Following this approach, we propose a novel solution method named Absorbing Markov Chains Approximation (AMCA) based on the transient regime analysis. Briefly, we model the time the system spends in a series of subsets of states by a phase-type distribution and, for each of them, determine the probabilities of finding the system in each state of this subset until absorption. We compare the AMCA performance to that obtained by classical methods and by a recently proposed approach that aims at generalizing the conventional quasi-stationary approximation. We find that AMCA has a more predictable behavior, is applicable to a wider range of time-scale separations, and achieves higher accuracy for a given computational cost.This research has been supported in part by the Ministry of Economy and Competitiveness of Spain under Grants TIN2013-47272-C2-1-R and TEC2015-71932-REDT. The research of L. Tello-Oquendo was supported in part by Programa de Ayudas de Investigacion y Desarrollo (PAID) of the Universitat Politecnica de Valencia.Tello Oquendo, LP.; Pla, V.; Martínez Bauset, J.; Casares Giner, V. (2016). Performance analysis of wireless networks based on time-scale separation: A new iterative method. Computer Communications. 86:40-48. https://doi.org/10.1016/j.comcom.2016.04.004S40488

Efficient Random Access Channel Evaluation and Load Estimation in LTE-A with Massive MTC

© 2019 IEEE. Personal use of this material is permitted. Permissíon from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertisíng 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."[EN] The deployment of machine-type communications (MTC) together with cellular networks has a great potential to create the ubiquitous Internet-of-Things environment. Nevertheless, the simultaneous activation of a large number of MTC devices (named UEs herein) is a situation difficult to manage at the evolved Node B (eNB). The knowledge of the joint probability distribution function (PDF) of the number of successful and collided access requests within a random access opportunity (RAO) is a crucial piece of information for contriving congestion control schemes. A closed-form expression and an efficient recursion to obtain this joint PDF are derived in this paper. Furthermore, we exploit this PDF to design estimators of the number of contending UEs in an RAO. Our numerical results validate the effectiveness of our recursive formulation and show that its computational cost is considerably lower than that of other related approaches. In addition, our estimators can be used by the eNBs to implement highly efficient congestion control methods.This work was supported in part by the Ministry of Economy and Competitiveness of Spain under Grants TIN2013-47272-C2-1-R and TEC2015-71932-REDT. The work of L. Tello-Oquendo was supported in part by the Universitat Politecnica de Valencia under the Programa de Ayudas de Investigacion y Desarrollo (PAID). The work of I. Leyva-Mayorga was supported in part by the CONACYT-Gobierno del Estado de Mexico under Grant 383936. The review of this paper was coordinated by Dr. Y. Ji.Tello-Oquendo, L.; Pla, V.; Leyva-Mayorga, I.; Martínez Bauset, J.; Casares-Giner, V.; Guijarro, L. (2019). Efficient Random Access Channel Evaluation and Load Estimation in LTE-A with Massive MTC. IEEE Transactions on Vehicular Technology. 68(2):1998-2002. https://doi.org/10.1109/TVT.2018.2885333S1998200268

Deep Reinforcement Learning Mechanism for Dynamic Access Control in Wireless Networks Handling mMTC

[EN] One important issue that needs to be addressed in order to provide effective massive deployments of IoT devices is access control. In 5G cellular networks, the Access Class Barring (ACB) method aims at increasing the total successful access probability by delaying randomly access requests. This mechanism can be controlled through the barring rate, which can be easily adapted in networks where Human-to-Human (H2H) communications are prevalent. However, in scenarios with massive deployments such as those found in IoT applications, it is not evident how this parameter should be set, and how it should adapt to dynamic traffic conditions. We propose a double deep reinforcement learning mechanism to adapt the barring rate of ACB under dynamic conditions. The algorithm is trained with simultaneous H2H and Machine-to-Machine (M2M) traffic, but we perform a separate performance evaluation for each type of traffic. The results show that our proposed mechanism is able to reach a successful access rate of 100 % for both H2H and M2M UEs and reduce the mean number of preamble transmissions while slightly affecting the mean access delay, even for scenarios with very high load. Also, its performance remains stable under the variation of different parameters. (C) 2019 Elsevier B.V. All rights reserved.The research of D. Pacheco-Paramo was supported by Universidad Sergio Arboleda, P.t. Tecnologias para la inclusion social y la competitividad economica. 0.E.6. The research of L Tello-Oquendo was conducted under project CONV.2018-ING010. Universidad Nacional de Chimborazo. The research of V. Pla and J. Martinez-Bauset was supported by Grant PGC2018-094151-B-I00 (MCIU/AEI/FEDER,UE).Pacheco-Paramo, DF.; Tello-Oquendo, L.; Pla, V.; Martínez Bauset, J. (2019). Deep Reinforcement Learning Mechanism for Dynamic Access Control in Wireless Networks Handling mMTC. Ad Hoc Networks. 94:1-14. https://doi.org/10.1016/j.adhoc.2019.101939S1149

On the accurate performance evaluation of the LTE-A random access procedure and the access class barring scheme

[EN] The performance evaluation of the random access (RA) in LTE-A has recently become a major research topic as these networks are expected to play a major role in future 5G networks. Up to now, the key performance indicators (KPIs) of the RA in LTE-A have been obtained either by performing a large number of simulations or by means of analytic models that, oftentimes, sacrifice precision in exchange for simplicity. In this paper, we present an analytical model for the performance evaluation of the LTE-A RA procedure that incorporates the access class barring (ACB) scheme. By means of this model, each and every one of the KPIs suggested by the 3GPP can be obtained with minimal error when compared with results obtained by simulation. To the best of our knowledge, this paper presents the most accurate analytical model, which can be easily adapted to incorporate modifications of network parameters and/or extensions to the LTE-A system. In addition, our model of the ACB scheme can be easily incorporated to other analytic models of similar nature without further modifications.This work was supported in part by the Ministry of Economy and Competitiveness of Spain under Grant TIN2013-47272-C2-1-R and Grant TEC2015-71932-REDT. The research of I. Leyva-Mayorga was supported under Grant 383936 CONACYT-Gobierno del Estado de Mexico 2014. The research of L. Tello-Oquendo was supported in part by Programa de Ayudas de Investigacion y Desarrollo, Universitat Politecnica de Valencia.Leyva-Mayorga, I.; Tello-Oquendo, L.; Pla, V.; Martínez Bauset, J.; Casares-Giner, V. (2017). On the accurate performance evaluation of the LTE-A random access procedure and the access class barring scheme. IEEE Transactions on Wireless Communications. 16(12):7785-7799. https://doi.org/10.1109/TWC.2017.2753784S77857799161

Adaptive access class barring for efficient mMTC

[EN] In massive machine-type communications (mMTC), an immense number of wireless devices communicate autonomously to provide users with ubiquitous access to information and services. The current 4G LTE-A cellular system and its Internet of Things (IoT) implementation, the narrowband IoT (NB-IoT), present appealing options for the interconnection of these wireless devices. However, severe congestion may arise whenever a massive number of highly-synchronized access requests occur. Consequently, access control schemes, such as the access class barring (ACB), have become a major research topic. In the latter, the precise selection of the barring parameters in a real-time fashion is needed to maximize performance, but is hindered by numerous characteristics and limitations of the current cellular systems. In this paper, we present a novel ACB configuration (ACBC) scheme that can be directly implemented at the cellular base stations. In our ACBC scheme, we calculate the ratio of idle to total available resources, which then serves as the input to an adaptive filtering algorithm. The main objective of the latter is to enhance the selection of the barring parameters by reducing the effect of the inherent randomness of the system. Results show that our ACBC scheme greatly enhances the performance of the system during periods of high congestion. In addition, the increase in the access delay during periods of light traffic load is minimal.This research has been supported in part by the Ministry of Economy and Competitiveness of Spain under Grant TIN2013-47272-C2-1-R and Grant TEC2015-71932-REDT. The research of I. Leyva-Mayorga was partially funded by grant 383936 CONACYT-GEM 2014.Leyva-Mayorga, I.; Rodríguez-Hernández, MA.; Pla, V.; Martínez Bauset, J.; Tello-Oquendo, L. (2019). Adaptive access class barring for efficient mMTC. Computer Networks. 149:252-264. https://doi.org/10.1016/j.comnet.2018.12.003S25226414