Resource dimensioning aspect of heterogeneous traffic with different service requirements: Integration versus segregation

In this paper, we consider the ATM networks in which the virtual path concept is implemented. The question of how to multiplex two or more diverse traffic classes while providing different quality of service requirements is a very complicated open problem. Two distinct options are available: integration and segregation. In an integration approach all the traffic from different connections are multiplexed onto one VP. This implies that the most restrictive QOS requirements must be applied to all services. Therefore, link utilization will be decreased because unnecessarily stringent QOS is provided to all connections. With the segregation approach the problem can be much simplified if different types of traffic are separated by assigning a VP with dedicated resources (buffers and links). Therefore, resources may not be efficiently utilized because no sharing of bandwidth can take place across the VP. The probability that the bandwidth required by the accepted connections exceeds the capacity of the link is evaluated with the probability of congestion (PC). Since the PC can be expressed as the CLP, we shall simply carry out bandwidth allocation using the PC. We first focus on the influence of some parameters (CLP, bit rate and burstiness) on the capacity required by a VP supporting a single traffic class using the new convolution approach. Numerical results are presented both to compare the required capacity and to observe which conditions under each approach are preferred

Optimal Traffic Grooming in WDM using Lighttours

Recent developments in optical communications have allowed simpler optical devices to improve network resource utilization. As such, we propose adding a lambda-monitoring device to a wavelength-routing switch (WRS) allowing better performance when traffic is routed and groomed. This device may allow a WRS to aggregate traffic over optical routes without incurring in optical-electrical-optical conversion for the existing traffic. In other words, optical routes can be taken partially to route demands creating a sort of "lighttours". In this paper, we compare the number of OEO conversions needed to route a complete given traffic matrix using either lighttours or lightpaths

An improved method for discovering link criticality in transport networks

Quantitatively assessing the importance or criticality of each link in a network is of practical value to operators, as that can help them to increase the network's resilience, provide more efficient services, or improve some other aspect of the service. Betweenness is a graph-theoretical measure of centrality that can be applied to communication networks to evaluate link importance. However, as we illustrate in this paper, the basic definition of betweenness centrality produces inaccurate estimations as it does not take into account some aspects relevant to networking, such as the heterogeneity in link capacity or the difference between node-pairs in their contribution to the total traffic. A new algorithm for discovering link centrality in transport networks is proposed in this paper. It requires only static or semi-static network and topology attributes, and yet produces estimations of good accuracy, as verified through extensive simulations. Its potential value is demonstrated by an example application. In the example, the simple shortest-path routing algorithm is improved in such a way that it outperforms other more advanced algorithms in terms of blocking ratio

All-Optical Unicast/Multicast Routing in WDM Networks

Optical transport networks (OTN) must be prepared in terms of better resource utilization, for accommodating unicast and multicast traffic together. Light-trees have been proposed for supporting multicast connections in OTN. Nevertheless when traffic grooming is applied in light-trees, resources can be underutilized as traffic can be routed to undesirable destinations in order to avoid optical-electrical-optical (OEO) conversions. In this paper, a novel architecture named S/G light- tree for supporting unicast/multicast connections is proposed. The architecture allows traffic dropping and aggregation in different wavelengths without performing OEO conversions. A heuristic that routes traffic demands using less wavelengths by taking advantage of the proposed architecture is designed as well. Simulation results show that the architecture can minimize the number of used wavelengths and OEO conversions when compared to light-trees

G+: Enhanced Traffic Grooming in WDM Mesh Networks using Lighttours

In this article, a new technique for grooming low-speed traffic demands into high-speed optical routes is proposed. This enhancement allows a transparent wavelength-routing switch (WRS) to aggregate traffic en route over existing optical routes without incurring expensive optical-electrical-optical (OEO) conversions. This implies that: a) an optical route may be considered as having more than one ingress node (all inline) and, b) traffic demands can partially use optical routes to reach their destination. The proposed optical routes are named "lighttours" since the traffic originating from different sources can be forwarded together in a single optical route, i.e., as taking a "tour" over different sources towards the same destination. The possibility of creating lighttours is the consequence of a novel WRS architecture proposed in this article, named "enhanced grooming" (G+). The ability to groom more traffic in the middle of a lighttour is achieved with the support of a simple optical device named lambda-monitor (previously introduced in the RingO project). In this article, we present the new WRS architecture and its advantages. To compare the advantages of lighttours with respect to classical lightpaths, an integer linear programming (ILP) model is proposed for the well-known multilayer problem: traffic grooming, routing and wavelength assignment The ILP model may be used for several objectives. However, this article focuses on two objectives: maximizing the network throughput, and minimizing the number of optical-electro-optical conversions used. Experiments show that G+ can route all the traffic using only half of the total OEO conversions needed by classical grooming. An heuristic is also proposed, aiming at achieving near optimal results in polynomial time

Asymmetric tunnels in P2MP LSPs as a label space reduction method

The objective of traffic engineering is to optimize network resource utilization. Although several works have been published about minimizing network resource utilization, few works have focused on LSR (label switched router) label space. This paper proposes an algorithm that takes advantage of the MPLS label stack features in order to reduce the number of labels used in LSPs. Some tunnelling methods and their MPLS implementation drawbacks are also discussed. The described algorithm sets up NHLFE (next hop label forwarding entry) tables in each LSR, creating asymmetric tunnels when possible. Experimental results show that the described algorithm achieves a great reduction factor in the label space. The presented works apply for both types of connections: P2MP (point-to-multipoint) and P2P (point-to-point)

A Label space reduction algorithm for P2MP LSPs using asymmetric tunnels

The aim of traffic engineering is to optimise network resource utilization. Although several works on minimizing network resource utilization have been published, few works have focused on LSR label space. This paper proposes an algorithm that uses MPLS label stack features in order to reduce the number of labels used in LSPs forwarding. Some tunnelling methods and their MPLS implementation drawbacks are also discussed. The algorithm described sets up the NHLFE tables in each LSR, creating asymmetric tunnels when possible. Experimental results show that the algorithm achieves a large reduction factor in the label space. The work presented here applies for both types of connections: P2MP and P2P

Mapping sub-flows to p2mp LSPs

In previous work we proposed a multi-objective traffic engineering scheme (MHDB-S model) using different distribution trees to multicast several flows. In this paper, we propose a heuristic algorithm to create multiple point-to-multipoint (p2mp) LSPs based on the optimum sub-flow values obtained with our MHDB-S model. Moreover, a general problem for supporting multicasting in MPLS networks is the lack of labels. To reduce the number of labels used, a label space reduction algorithm solution is also considered

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

Repercussions d’un tràfic forçat o lliure sobre el consum i pauta d’ingestió del vaquí lleter amb un sistema de munyida robotitzada

Avaluació de l’efecte del tipus de tràfic imposat a les vaques lleteres en sistemes de munyida automàtica sobre la freqüència de munyida, les necessitats d’alimentació, el comportament alimentari i la producció i composició de la llet

Immersió lingüística, cultural i acadèmica per a estudiants de Telecomunicació

L’Escola Tècnica Superior d’Enginyers de Telecomunicació (ETSET) de la Universitat Politècnica de València (UPV) promou la mobilitat dels seus estudiants i professors, no només a través de programes nacionals –SICUE-Sèneca– o internacionals (ERASMUS, PROMOE), sinó també per la realització de viatges de pràctiques de llengua estrangera. D’aquesta manera, els estudiants matriculats en les assignatures de francès, anglès o alemany poden beneficiar- se d’una estada a França, Gran Bretanya o Alemanya, visitant-ne les universitats i empreses del sector. En aquesta comunicació ens remetem a l’últim viatge realitzat a París al març passat, durant el qual quinze estudiants de l’ETSET, matriculats en els cinc grups de les assignatures de francès (nivell bàsic, intermedi i avançat), van visitar una Grande École, l’ENSEA (École Nationale Supérieure de l’Électronique et de ses Applications). La visita, coordinada i programada entre els professors responsables d’ambdues escoles, va consistir a efectuar presentacions institucionals (escola, universitat d’origen) i generals (informació sobre la ciutat i la seua cultura) per part dels mateixos estudiants espanyols i francesos en els diferents grups de les assignatures d’espanyol. Per a fer-ho, cada grup havia preparat la presentació en PowerPoint de la seua escola o ciutat en la llengua d’estudi. Aquest tipus d’activitats facilita la immersió lingüística, cultural i acadèmica dels estudiants, de manera que els permet rebre informació de primera mà sobre el panorama dels seus estudis en un altre país, i alhora patrocinen la seua pròpia escola entre els estudiants estrangers

Tràfic il.legal d'animals i plantes. 'Tráfico ilegal de animales y plantas'.

Incluye resumen en inglés y castellano. Fecha tomada del código del documento

Derivaci??n e integraci??n de funciones de variable compleja con DERIVE : un estudio de innovaci??n curricular en primer curso de Ingenier??a T??cnica de Telecomunicaci??n

Contribuir a la comprensi??n de la realidad de los procesos y fen??menos de la Educaci??n Matem??tica en los estudios de Ingenier??a, para poder intervenir sobre ella en orden a su optimizaci??n. Profesores de la asignatura, grupos de alumnos diferentes y bajo la responsabilidad de investigadores. Analiza la comparaci??n de efectos de la metodolog??a did??ctica modificada y de la metodolog??a did??ctica usual o tradicional y se aprovecha el desarrollo experimental para reflexionar sobre la validez y fiabilidad de los datos, la potencialidad innovadora de este tipo de estudios, la pertinencia y utilidad del marco te??rico y metodol??gico empleado. Prueba de nivel, ficheros de DERIVE, prueba de evaluaci??n, observadores, encuesta, entrevista, an??lisis de datos y elaboraci??n de informes. Para la prueba se escogieron 2 grupos de estudio y una prueba de 10 ejercicios; la calificaci??n m??xima es de 10 puntos y la m??nima de cero. 1) La prueba de nivel ha servido para obtener informaci??n sobre la equivalencia de los grupos en cuanto a conocimientos, capacidades y destrezas matem??ticas relacionadas con el problema de investigaci??n. 2) Los datos indican que la utilizaci??n de DERIVE favorece la participaci??n activa de los alumnos y su protagonismo frente al medio tecnol??gico, incrementa el grado de autonom??a en el desarrollo de la clase y aumenta el inter??s y la motivaci??n pro lo que hacen. 3) El an??lisis de los ficheros pone de manifiesto la eficacia de DERIVE debida a la facilidad de la realizaci??n de comandos. 4) El rendimiento del grupo experimental es superior al rendimiento del grupo control. 5) Las informaciones aportadas por los propios alumnos abundan en la equivalencia entre los dos grupos entre m??ltiples aspectos. 6) DERIVE facilita y mejora: el aprendizaje, la comprensi??n, la motivaci??n, la comunicaci??n entre alumnos, la comunicaci??n profesor-alumno, y el rendimiento en ex??menes. No modifica la actitud de los alumnos ni produce variaciones negativas sobre el aprendizaje. Se ha conseguido analizar la viabilidad y los efectos del tratamiento modificado sobre el aprendizaje, la motivaci??n, las actitudes, el rendimiento de los alumnos y el propio proceso did??ctico y sus distintos factores. Se ha analizado a fondo la realidad sin manipulaciones extra??as que distorsionen su naturaleza y sus caracter??sticas. Se han efectuado cambios curriculares posibles y se han descartado otros no compatibles con el desarrollo usual. Se han introducido tareas y usos novedosos en el dise??o y desarrollo. Se han creado y difundido conocimientos fundados sobre los fen??menos curriculares relacionados con la Educaci??n Matem??tica en el aula ordinaria. Se ha sustituido el m??todo de ense??anza usual por nuevos elementos adaptados a las nuevas condiciones, medios y situaciones. Y por ??ltimo, se ha proporcionado una nueva v??a para la formaci??n permanente del Profesorado.

Design and evaluation of an optical switching node

[EN]For a good development of elastic optical networks, the design of flexible optical switching nodes is required. This work analyses the previously proposed flexible architectures and, based on the most appropriate, which is the Architecture on Demand (AoD), proposes a specific configuration of the node that includes spatial and spectral switching and the wavelength conversion functionality with a low blocking probability and the minimum amount of modules; the characteristics of the traffic that the designed node is able to cope with are specified in the last chapter. An evaluation of the designed node is also done, and, compared to the other architectures, it is shown that the Architecture on Demand gives better results than others and that it has a higher potential for future developments.