Contribuciones en arquitectura de redes de conmutadores transparentes ethernet de altas prestaciones

Las redes campus y de centros de datos requieren hoy en día un alto rendimiento y gestionabilidad, todo ello dentro de un coste razonable, especialmente en redes de centros de datos, en las que se tiende a utilizar un mayor número de dispositivos genéricos (commodity) en lugar de alternativas más complejas y de mayor precio por tanto. Las redes de conmutadores transparentes Ethernet se presentan como la primera opción en este ámbito. Sin embargo, el empleo del protocolo de árbol de expansión (Spanning Tree Protocol, STP) como paradigma para propagar los mensajes a través de la red y evitar bucles es una evidente limitación del desempeño y el tamaño de las redes Ethernet. Mientras que los dos recientes y principales estándares Shortest Path Bridging (SPB) y Routing Bridges (RBridges, TRILL) permiten la utilización de los todos los enlaces de la infraestructura para obtener caminos mínimos, pero utilizan un protocolo de estado de enlace, operando en capa dos, y no cumplen con el principio básico de simplicidad de los conmutadores transparentes puros de capa dos. \ud Esta tesis presenta diversas contribuciones en conmutadores transparentes Ethernet del tipo genéricamente denominado por puentes de caminos mínimos (shortest path bridges) para resolver las grandes restricciones que impone el protocolo de árbol de expansión, pero que se caracterizan por evitar el uso de algoritmos de encaminamiento, enfoque actualmente predominante en las propuestas tanto estándar como propietarias. Se evita así la complejidad de utilizar un protocolo de estado de enlace (como IS-IS en SPB y TRILL), mientras que a la vez se aprovecha el concepto básico de ¿difundir para aprender¿ de los conmutadores transparentes puros para explorar todos los caminos en la red usando todos los enlaces de la topología. Con este principio, introducimos la familia All-Path, una familia de protocolos de puentes transparentes que ofrece caminos de mínima latencia con reparto de carga automático y que se adapta a diferentes requirimientos de escalabilidad y balanceo de carga de las topologías. También presentamos Torii-HLMAC, un protocolo distribuido, tolerante a fallos, sin configuración, con direccionamiento y encaminamiento basado en árboles múltiples y reparación sobre la marcha, específico para redes de centros de datos, principalmente los llamados fat trees.\ud Palabras clave: protocolos, redes de computadores, conmutadores transparentes, direccionamiento jerárquico, caminos de mínima latencia, multicaminos, reparto de carga

Online Teaching Methodologies in Higher Education Credit Mobility Courses: ErasmusX pilot project

Este documento se considera que es un capítulo de libro en lugar de un artículoSixth International Conference on e-Learning (econf)Based on Erasmus credit mobility programs, ErasmusX is a project envisaged to offer students the possibility to add value to international exchange periods by combining online certified studies with further professional or academic experiences abroad. However, differences between national higher education systems and teaching styles can lead to issues concerning the recognition of credits, which makes necessary to establish common basic procedures. For this purpose, five different European Higher Education Institutions which have traditionally based their academic organization in the face to face credit system, have joined to develop on-line certified courses on several pre-defined areas following common practices. Bearing in mind this purpose, this communication focuses on the proposal of key pedagogical models, approaches and strategies to consider when designing online courses for mobility students. The revision of existing practices underline that online teaching requires not only an adjustment of the role of professors and students, but also a different structure of the courses based on a flexible online instructional design. The methods and models revised in this preliminary study point to the need of incorporating a collaborative online teaching approach with processed educational technology in English mediated instruction

HDDP: Hybrid Domain Discovery Protocol for heterogeneous devices in SDN

Computer networks are adopting the new Software-Defined Networking (SDN) architecture, however not all devices can support it, mainly due to power and computational constraints. This paper proposes the Hybrid Domain Discovery Protocol (HDDP), a new discovery protocol that enhances theexisting OpenFlow Discovery Protocol (OFDP). HDDP allows thediscovery of hybrid network topologies composed of both SDNand non-SDN devices, which no other state-of-the-art protocolcan achieve. HDDP has been implemented in a software switchand emulated in diverse networks, where it discovers hybrid topologies by using a number of messages similar to competitors,as they only discover SDN devices.Comunidad de MadridUniversidad de Alcal

Torii: Multipath Distributed Ethernet Fabric Protocol for Data Centers with Zero-Loss Path Repair

This paper describes and evaluates Torii, a layer-two data center network fabric protocol. The main features of Torii are being fully distributed, scalable, fault-tolerant and with automatic setup. Torii is based on multiple, tree-based, topological MAC addresses that are used for table-free forwarding over multiple equal-cost paths, and it is capable of rerouting frames around failed links on the fly without needing a central fabric manager for any function. To the best of our knowledge, it is the first protocol that does not require the exchange of periodic messages to work under normal conditions and to recover from link failures, as Torii exchanges messages just once. Moreover, another important characteristic of Torii is that it is compatible with a wide range of data center topologies. Simulation results show an excellent distribution of traffic load and latencies, similar to shortest path protocols

Torii: Multipath Distributed Ethernet Fabric Protocol for Data Centers with Zero-Loss Path Repair

This paper describes and evaluates Torii, a layer-two data center network fabric protocol. The main features of Torii are being fully distributed, scalable, fault-tolerant and with automatic setup. Torii is based on multiple, tree-based, topological MAC addresses that are used for table-free forwarding over multiple equal-cost paths, and it is capable of rerouting frames around failed links on the fly without needing a central fabric manager for any function. To the best of our knowledge, it is the first protocol that does not require the exchange of periodic messages to work under normal conditions and to recover from link failures, as Torii exchanges messages just once. Moreover, another important characteristic of Torii is that it is compatible with a wide range of data center topologies. Simulation results show an excellent distribution of traffic load and latencies, similar to shortest path protocols

Stateless Flow-Zone Switching Using Software-Defined Addressing

The trend toward cloudification of communication networks and services, with user data and applications stored and processed in data centers, pushes the limits of current Data Center Networks (DCNs), requiring improved scalability, resiliency, and performance. Here we consider a DCN forwarding approach based on software-defined addressing (SDA), which embeds semantics in the Medium Access Control (MAC) address and thereby enables new forwarding processes. This work presents Flow-Zone Switching (FZS), a loop-free location-based source-routing solution that eliminates the need for forwarding tables by embedding routing instructions and flow identifiers directly in the flow-zone software-defined address. FZS speeds the forwarding process, increasing the throughput and reducing the latency of QoS-sensitive flows while reducing the capital and operational costs of switching. This paper presents details of FZS and a performance evaluation within a complete DCN.This work was supported in part by the H2020 Europe/Taiwan Joint Action 5G-DIVE under Grant 859881, in part by the Spanish State Research Agency through the TRUE5G Project under Grant PID2019-108713RB-C52/AEI/10.13039/501100011033, and in part by the Comunidad de Madrid through the Project TAPIR-CM under Grant S2018/TCS-4496

Analysis of P4 and XDP for IoT programmability in 6G and beyond

Recently, two technologies have emerged to provide advanced programmability in Software-Defined Networking (SDN) environments, namely P4 and XDP. At the same time, the Internet of Things (IoT) represents a pillar of future 6G networks, which will be also sustained by SDN. In this regard, there is a need to analyze the suitability of P4 and XDP for IoT. In this article, we aim to compare both technologies to help future research efforts in the field. To this purpose, we evaluate both technologies by implementing diverse use cases, assessing their performance and providing a quick qualitative overview. All tests and designed scenarios are publicly available in GitHub to guarantee replication and serve as initial steps for researchers that want to initiate in the field. Results illustrate that currently XDP is the best option for constrained IoT devices, showing lower latency times, half of CPU usage, and reduced memory in comparison with P4. However, development of P4 programs is more straightforward and the amount of code lines is more similar regardless of the scenario. Additionally, P4 has a lot of potential in IoT if a special effort is made to improve the most common software target, BMv2.Comunidad de MadridJunta de Comunidades de Castilla-La ManchaUniversidad de Alcal