Evaluating the probability and the impact of a failure in GMPLS based networks

In this paper, we define a new scheme to develop and evaluate protection strategies for building reliable GMPLS networks. This is based on what we have called the network protection degree (NPD). The NPD consists of an a priori evaluation, the failure sensibility degree (FSD), which provides the failure probability, and an a posteriori evaluation, the failure impact degree (FID), which determines the impact on the network in case of failure, in terms of packet loss and recovery time. Having mathematical formulated these components, experimental results demonstrate the benefits of the utilization of the NPD, when used to enhance some current QoS routing algorithms in order to offer a certain degree of protection

Enhancing fault management performance of two-step QoS routing algorithms in GMPLS networks

In this paper a novel methodology aimed at minimizing the probability of network failure and the failure impact (in terms of QoS degradation) while optimizing the resource consumption is introduced. A detailed study of MPLS recovery techniques and their GMPLS extensions are also presented. In this scenario, some features for reducing the failure impact and offering minimum failure probabilities at the same time are also analyzed. Novel two-step routing algorithms using this methodology are proposed. Results show that these methods offer high protection levels with optimal resource consumption

Admission Control for TCP Flows Using Packet Classes and Edge-to-edge Measurements of Aggregates

TCP flows from applications such as the web or ftp are well supported by a Guaranteed Minimum Throughput Service (GMTS), which provides a minimum network throughput to the flow and, if possible, an extra throughput. We propose a scheme for a GMTS using Admission Control (AC) that is able to provide different minimum throughput to different users and that is suitable for "standard" TCP flows. Moreover, we consider a multidomain scenario where the scheme is used in one of the domains, and we propose some mechanisms for the interconnection with neighbor domains. The whole scheme uses a small set of packet classes in a core-stateless network where each class has a different discarding priority in queues assigned to it. The AC method involves only edge nodes and uses a special probing packet flow (marked as the highest discarding priority class) that is sent continuously from ingress to egress through a path. The available throughput in the path is obtained at the egress using measurements of flow aggregates, and then it is sent back to the ingress. At the ingress each flow is detected using an implicit way and then it is admission controlled. If it is accepted, it receives the GMTS and its packets are marked as the lowest discarding priority classes; otherwise, it receives a best-effort service. The scheme is evaluated through simulation in a simple "bottleneck" topology using different traffic loads consisting of "standard" TCP flows that carry files of varying sizes

Adding QoS protection in order to enhance MPLS QoS routing

In this paper, a method for enhancing current QoS routing methods by means of QoS protection is presented. In an MPLS network, the segments (links) to be protected are predefined and an LSP request involves, apart from establishing a working path, creating a specific type of backup path (local, reverse or global). Different QoS parameters, such as network load balancing, resource optimization and minimization of LSP request rejection should be considered. QoS protection is defined as a function of QoS parameters, such as packet loss, restoration time, and resource optimization. A framework to add QoS protection to many of the current QoS routing algorithms is introduced. A backup decision module to select the most suitable protection method is formulated and different case studies are analyzed

On optimal computation of MPLS label binding for multipoint-to-point connections

Most network operators have considered reducing Label Switched Routers (LSR) label spaces (i.e. the number of labels that can be used) as a means of simplifying management of underlaying Virtual Private Networks (VPNs) and, hence, reducing operational expenditure (OPEX). This letter discusses the problem of reducing the label spaces in Multiprotocol Label Switched (MPLS) networks using label merging - better known as MultiPoint-to-Point (MP2P) connections. Because of its origins in IP, MP2P connections have been considered to have tree- shapes with Label Switched Paths (LSP) as branches. Due to this fact, previous works by many authors affirm that the problem of minimizing the label space using MP2P in MPLS - the Merging Problem - cannot be solved optimally with a polynomial algorithm (NP-complete), since it involves a hard- decision problem. However, in this letter, the Merging Problem is analyzed, from the perspective of MPLS, and it is deduced that tree-shapes in MP2P connections are irrelevant. By overriding this tree-shape consideration, it is possible to perform label merging in polynomial time. Based on how MPLS signaling works, this letter proposes an algorithm to compute the minimum number of labels using label merging: the Full Label Merging algorithm. As conclusion, we reclassify the Merging Problem as Polynomial-solvable, instead of NP-complete. In addition, simulation experiments confirm that without the tree-branch selection problem, more labels can be reduced

Full label space reduction in MPLS networks: asymmetric merged tunneling

Traffic Engineering objective is to optimize network resource utilization. Although several works have been published about minimizing network resource utilization in MPLS networks, few of them have been focused in LSR label space reduction. This letter studies Asymmetric Merged Tunneling (AMT) as a new method for reducing the label space in MPLS network. The proposed method may be regarded as a combination of label merging (proposed in the MPLS architecture) and asymmetric tunneling (proposed recently in our previous works). Finally, simulation results are performed by comparing AMT with both ancestors. They show a great improvement in the label space reduction factor

Label Space Reduction in MPLS Networks: How Much Can A Single Stacked Label Do?

Most network operators have considered reducing LSR label spaces (number of labels used) as a way of simplifying management of underlaying virtual private networks (VPNs) and therefore reducing operational expenditure (OPEX). The IETF outlined the label merging feature in MPLS-allowing the configuration of multipoint-to-point connections (MP2P)-as a means of reducing label space in LSRs. We found two main drawbacks in this label space reduction a)it should be separately applied to a set of LSPs with the same egress LSR-which decreases the options for better reductions, and b)LSRs close to the edge of the network experience a greater label space reduction than those close to the core. The later implies that MP2P connections reduce the number of labels asymmetrically

All-Optical Label Stacking: Easing the Trade-offs Between Routing and Architecture Cost in All-Optical Packet Switching

All-optical label swapping (AOLS) forms a key technology towards the implementation of all-optical packet switching nodes (AOPS) for the future optical Internet. The capital expenditures of the deployment of AOLS increases with the size of the label spaces (i.e. the number of used labels), since a special optical device is needed for each recognized label on every node. Label space sizes are affected by the way in which demands are routed. For instance, while shortest-path routing leads to the usage of fewer labels but high link utilization, minimum interference routing leads to the opposite. This paper studies all-optical label stacking (AOLStack), which is an extension of the AOLS architecture. AOLStack aims at reducing label spaces while easing the compromise with link utilization. In this paper, an integer lineal program is proposed with the objective of analyzing the softening of the aforementioned trade-off due to AOLStack. Furthermore, a heuristic aiming at finding good solutions in polynomial-time is proposed as well. Simulation results show that AOLStack either a) reduces the label spaces with a low increase in the link utilization or, similarly, b) uses better the residual bandwidth to decrease the number of labels even more

Amenzas a través de la telefonía móvil e internet: perfil psicológico y consecuencias emocionales

En los últimos años se ha producido un incremento del uso de la telefonía móvil e Internet con fines intimidatorios o simplemente para amenazar a los iguales en los centros escolares de nuestro país. Con la voluntad de aportar datos que puedan ayudar a su prevención, se ha realizado un estudio de encuesta en el que se ha obtenido información relativa a las amenazas recibidas a través de los nuevos medios de comunicación, es decir, Internet y la telefonía móvil. Los resultados indican que un 23.3% de los estudiantes de los centros públicos de Enseñanza Secundaria Obligatoria de la ciudad de Girona (Cataluña), durante el curso escolar, han recibido vía Internet o telefonía móvil algún mensaje que, por su contenido, ha supuesto una amenaza para su bienestar. Se analizan las consecuencias emocionales y las estrategias de afrontamiento utilizadas por parte de estos adolescentes

Empleo de herramientas telemáticas para monitorizar el aprendizaje del alumno

En este artículo se hace énfasis en la necesidad de contar con herramientas de monitorización del proceso de aprendizaje el cual, en el contexto del crédito ECTS, ha de contemplar en su organización el trabajo continuado que ha de realizar el alumno dentro y fuera del aula. La herramienta presentada permite al profesor y al alumno obtener información sobre el proceso de aprendizaje, permitiendo detectar irregularidades tales como desequilibrios de carga respecto a la planificación o problemas recurrentes de los alumnos. Estas herramientas necesitan de una motivación para la participación de profesores y alumnos para un aprovechamiento eficiente de las mismas

Elaboració d'una eina d'avaluació de mòduls de màster segons els estudiants

En aquest estudi es presenta un instrument d'avaluació d'un mòdul docent de màster universitari en forma d'autoinforme a respondre pels estudiants. Aquest qüestionari consta de preguntes de format tancat i obert i cerca recollir informació sobre: correspondència dels continguts amb els descriptors del mòdul, avenç en les competències del programa, idoneïtat de la metodologia docent, funcionalitat dels aprenenentatges assolits, pertinença del tipus d'avaluació, i elements positius i a millorar del mòdul. Aquest instrument s'ha administrat per avaluar un mateix mòdul de màster en els anys acadèmics 2009-10 i 2010-11. Se'n presenten els resultats i s'analitza la seva utilitat

Enseñanzas prácticas en materias IUS-históricas adaptadas al EEES

El desarrollo de la estrategia conocida como 'Seminario' tiende a aplicar nuevos instrumentos de aprendizaje del alumno, así como la incursión en la resolución de breves ejercicios de investigación para el inicio en la práctica investigadora. La Historia del Derecho propicia la participación elevada del alumno en este tipo de docencia práctica, por lo que presentamos la articulación de la misma a través de su diseño

Propuesta de autogestión del aprendizaje basada en principios del deporte de competición

La propuesta se lleva a cabo en una asignatura de la licenciatura de CC. de la Actividad Física y del Deporte denominada Enseñanza del Voleibol. La adquisición del conocimiento se convierte en un reto colectivo. Se forman equipos y se delega el protagonismo en el proceso de la consecución de ese reto en el equipo. Se crea un sistema complejo de evaluación que genera interdependencia y la necesidad de entablar mecanismos de cooperación. Se muestra una mejora en las pruebas teóricas como en las prácticas. Además, el nivel de satisfacción de los alumnos y la valoración de la asignatura son muy elevados

Seguretat i sostenibilitat: elaboració d'un model de procediment normalitzat de treball (pnt) com a eina docent per a l'autoaprenentatge en els tallers de les facultats de belles arts.

Seguretat i sostenibilitat: elaboració d'un model de procediment normalitzat de treball (pnt) com a eina docent per a l'autoaprenentatge en els tallers de les facultats de belles arts. La implementació dels nous graus requereix la integració dels conceptes i metodologies relacionades amb la seguretat, la prevenció de riscos laborals i la protecció del medi ambient. En aquest context, un equip de professorat de les facultats de Belles Arts (UB, UPV, UCLM) ha desenvolupat un projecte d'innovació docent, una de les parts fonamentals del qual, ha estat la ideació i creació d'un model de procediment normalitzat de treball (PNT) i la seva aplicació en experiències pilot realitzades en diverses pràctiques als tallers i laboratoris. El PNT s'ha mostrat com una eina bàsica per a l'autoaprenentatge, que, així mateix, garanteix l'adquisició d'aquelles competències transversals relacionades amb la seguretat i la sostenibilitat

Una Experiencia de trabajo cooperativo en economía de la empresa

El objeto de este trabajo se centra en el aprendizaje cooperativo. En concreto en el análisis de la introducción de una experiencia de este tipo en el segundo curso de una de las nuevas titulaciones de grado. Se pretende analizar entre otras cuestiones la puesta en marcha, la valoración del alumnado sobre este modo de trabajo, la cohabitación con otros medios de evaluación y trabajo más tradicionales y por último su efecto sobre los resultados finales del alumno en la asignatura Learning -- Evaluation Aprenentatge -- Avaluació Group work in education