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Análise de desempenho da agregação de tráfego IP em redes WDM com variação da granularidade dos fluxos. / Performance analysis of IP traffic grooming over WDM networks with variable granularity flows.Oliveira, Jaime Juliano de 03 October 2006 (has links)
O presente trabalho trata das estratégias de agregação de tráfego IP nas redes óticas WDM. Utilizar todo um comprimento de onda para transportar um único fluxo de dados numa rede WDM é ineficiente. O problema conhecido como agregação de tráfego consiste na multiplexação de distintos fluxos de tráfego em um mesmo comprimento de onda sobre um caminho ótico. A alocação de múltiplos fluxos de tráfego em comprimentos de onda é realizada por protocolos de controle de admissão, roteamento e designação de comprimento de onda (RWA) e algoritmos de agregação de tráfego. Neste trabalho é simulado o comportamento dinâmico e elástico do tráfego IP diretamente sobre a camada ótica. Com base nos resultados das simulações determinam-se os efeitos da granularidade dos fluxos IP nos parâmetros de desempenho da rede. As topologias utilizadas durante as simulações são das redes NSFNET e Kyatera. É estabelecida também uma correlação entre a granularidade dos fluxos de tráfego e os parâmetros de desempenho da rede. / The present work covers the IP traffic grooming strategies in optical WDM networks. Using an entire wavelength to transport an individual traffic flow in a WDM network is inefficient. The problem known as traffic grooming consists in the multiplexing of different traffic flows in a single wavelength within a lightpath. The allocation of multiple traffic flows is performed by routing and wavelength assignment (RWA) and traffic grooming algorithms. In this work it is simulated the dynamic and elastic behavior of IP traffic directly on top of the optical layer. Based on the simulation results the effects of the IP traffic flow granularity on the network performance parameters are determined. The simulated topologies are the NSFNET and Kyatera. It is also established the correlation between the traffic flow granularity and the network performance parameters.
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Análise de desempenho da agregação de tráfego IP em redes WDM com variação da granularidade dos fluxos. / Performance analysis of IP traffic grooming over WDM networks with variable granularity flows.Jaime Juliano de Oliveira 03 October 2006 (has links)
O presente trabalho trata das estratégias de agregação de tráfego IP nas redes óticas WDM. Utilizar todo um comprimento de onda para transportar um único fluxo de dados numa rede WDM é ineficiente. O problema conhecido como agregação de tráfego consiste na multiplexação de distintos fluxos de tráfego em um mesmo comprimento de onda sobre um caminho ótico. A alocação de múltiplos fluxos de tráfego em comprimentos de onda é realizada por protocolos de controle de admissão, roteamento e designação de comprimento de onda (RWA) e algoritmos de agregação de tráfego. Neste trabalho é simulado o comportamento dinâmico e elástico do tráfego IP diretamente sobre a camada ótica. Com base nos resultados das simulações determinam-se os efeitos da granularidade dos fluxos IP nos parâmetros de desempenho da rede. As topologias utilizadas durante as simulações são das redes NSFNET e Kyatera. É estabelecida também uma correlação entre a granularidade dos fluxos de tráfego e os parâmetros de desempenho da rede. / The present work covers the IP traffic grooming strategies in optical WDM networks. Using an entire wavelength to transport an individual traffic flow in a WDM network is inefficient. The problem known as traffic grooming consists in the multiplexing of different traffic flows in a single wavelength within a lightpath. The allocation of multiple traffic flows is performed by routing and wavelength assignment (RWA) and traffic grooming algorithms. In this work it is simulated the dynamic and elastic behavior of IP traffic directly on top of the optical layer. Based on the simulation results the effects of the IP traffic flow granularity on the network performance parameters are determined. The simulated topologies are the NSFNET and Kyatera. It is also established the correlation between the traffic flow granularity and the network performance parameters.
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Optimization in graphs under degree constraints. application to telecommunication networksSau Valls, Ignasi 16 October 2009 (has links)
La premi ere partie de cette th ese s'int eresse au groupage de tra c dans les
r eseaux de t el ecommunications. La notion de groupage de tra c correspond a l'agr egation
de
ux de faible d ebit dans des conduits de plus gros d ebit. Cependant, a chaque insertion
ou extraction de tra c sur une longueur d'onde il faut placer dans le noeud du r eseau un
multiplexeur a insertion/extraction (ADM). De plus il faut un ADM pour chaque longueur
d'onde utilis ee dans le noeud, ce qui repr esente un co^ut d' equipements important. Les objectifs
du groupage de tra c sont d'une part le partage e cace de la bande passante et
d'autre part la r eduction du co^ut des equipements de routage. Nous pr esentons des r esultats
d'inapproximabilit e, des algorithmes d'approximation, un nouveau mod ele qui permet
au r eseau de pouvoir router n'importe quel graphe de requ^etes de degr e born e, ainsi que
des solutions optimales pour deux sc enarios avec tra c all-to-all: l'anneau bidirectionnel
et l'anneau unidirectionnel avec un facteur de groupage qui change de mani ere dynamique.
La deuxi eme partie de la th ese s'interesse aux probl emes consistant a trouver des sousgraphes
avec contraintes sur le degr e. Cette classe de probl emes est plus g en erale que
le groupage de tra c, qui est un cas particulier. Il s'agit de trouver des sous-graphes
d'un graphe donn e avec contraintes sur le degr e, tout en optimisant un param etre du
graphe (tr es souvent, le nombre de sommets ou d'ar^etes). Nous pr esentons des algorithmes
d'approximation, des resultats d'inapproximabilit e, des etudes sur la complexit e
param etrique, des algorithmes exacts pour les graphes planaires, ainsi qu'une m ethodologie
g en erale qui permet de r esoudre e cacement cette classe de probl emes (et de mani ere
plus g en erale, la classe de probl emes tels qu'une solution peut ^etre cod e avec une partition
d'un sous-ensemble des sommets) pour les graphes plong es dans une surface.
Finalement, plurieurs annexes pr esentent des r esultats sur des probl emes connexes.
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Paving the Way for Next Generation Wireless Data Center NetworksAlGhadhban, Amer M. 05 1900 (has links)
Data Centers (DCs) have become an intrinsic element of emerging technologies such as big data, artificial intelligence, cloud services; all of which entails interconnected and sophisticated computing and storage resources. Recent studies of conventional data center networks (DCNs) revealed two key challenges: a biased distribution of inter-rack traffic and unidentified flow classes: delay sensitive mice flows (MFs) and throughput-hungry elephant flows (EFs). Unfortunately, existing DCN topologies support only uniform distribution of capacities, provide limited bandwidth flexibilities and lacks of efficient flow classification mechanism.
Fortunately, wireless DCs can leverage wireless communication emerging technologies, such as multi-terabit free-space optic (FSO), to provide flexible and reconfigurable DCN topologies. It is worth noting that indoor FSO links are less vulnerable to outdoor FSO channel impairments. Consequently, indoor FSO links are more robust and can offer high bandwidths with long stability, which can further be enhanced with wavelength division multiplexing (WDM) methods. In this thesis, we alleviate the bandwidth inefficiency by FSO links that have the desired agility by allocating the transmission powers to adapt link capacity for dynamically changing traffic conditions, and to reduce the maintenance costs and overhead.
While routing the two classes along the same path causes unpleasant consequences, the DC researchers proposed traffic management solutions to treat them separately. However, the solutions either suffer from packet reordering and high queuing delay, or lack of accurate visibility and estimation on end-to-end path status. Alternatively, we leverage WDM to design elastic network topologies (i.e., part of the wavelengths are assigned to route MFs and the remaining for EFs). Since bandwidth demands can be lower than available capacity of WDM channels, we use traffic grooming to aggregate multiple flows into a larger flow and to enhance the link utilization.
On the other hand, to reap the benefits of the proposed WDM isolated topology, an accurate and fast EF detection mechanism is necessary. Accordingly, we propose a scheme that uses TCP communication behavior and collect indicative packets for its flow classification algorithm, it demonstrates perfect flow classification accuracy, and is in order of magnitudes faster than existing solutions with low communication and computation overhead.
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Reconfigurable traffic grooming with differentiated reliability in DWDM mesh networksHu, Weiwei 01 May 2010 (has links)
Optical networks employing wavelength division multiplexing technology have been well recognized as the core networks for the next generation Internet. In such networks, any fiber cut or node failure may lead to huge data loss. Thus, reliability is of great importance in the design of modern high-speed networks. At the same time, traffic grooming is another important design objective since it addresses multi-granularity traffic. The traditional routing approaches with differentiated services do not consider the traffic grooming case or reconfiguration method. Therefore, they are not resource-efficient for the next generation Internet. In this dissertation, an effective reconfigurable traffic grooming with differentiated reliability scheme is proposed to efficiently use network resources. Compared with the conventional rerouting method, the proposed scheme makes the network more robust and immune from service interruptions. An integer linear programming (ILP) formulation is presented first. By solving the ILP formulation, an optimal solution is obtained for each incoming connection request. However, the solution is so time consuming, a heuristic algorithm is introduced to get an approximate optimal solution. The performance evaluation indicates that the connection blocking probability can be decreased greatly by the proposed scheme.
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Optimization in Graphs under Degree Constraints. Application to Telecommunication NetworksSau, Ignasi 16 October 2009 (has links) (PDF)
La première partie de cette thèse s'intéresse au groupage de trafic dans les réseaux de télécommunications. La notion de groupage de trafic correspond à l'agrégation de flux de faible débit dans des conduits de plus gros débit. Cependant, à chaque insertion ou extraction de trafic sur une longueur d'onde il faut placer dans le noeud du réseau un multiplexeur à insertion/extraction (ADM). De plus il faut un ADM pour chaque longueur d'onde utilisée dans le noeud, ce qui représente un coût d'équipements important. Les objectifs du groupage de trafic sont d'une part le partage efficace de la bande passante et d'autre part la réduction du coût des équipements de routage. Nous présentons des résultats d'inapproximabilité, des algorithmes d'approximation, un nouveau modèle qui permet au réseau de pouvoir router n'importe quel graphe de requêtes de degré borné, ainsi que des solutions optimales pour deux scénarios avec trafic all-to-all: l'anneau bidirectionnel et l'anneau unidirectionnel avec un facteur de groupage qui change de manière dynamique. La deuxième partie de la thèse s'intéresse aux problèmes consistant à trouver des sous-graphes avec contraintes sur le degré. Cette classe de problèmes est plus générale que le groupage de trafic, qui est un cas particulier. Il s'agit de trouver des sous-graphes d'un graphe donné avec contraintes sur le degré, tout en optimisant un paramètre du graphe (très souvent, le nombre de sommets ou d'arêtes). Nous présentons des algorithmes d'approximation, des résultats d'inapproximabilité, des études sur la complexité paramétrique, des algorithmes exacts pour les graphes planaires, ainsi qu'une méthodologie générale qui permet de résoudre efficacement cette classe de problèmes (et de manière plus générale, la classe de problèmes tels qu'une solution peut être codé avec une partition d'un sous-ensemble des sommets) pour les graphes plongés dans une surface. Finalement, plusieurs annexes présentent des résultats sur des problèmes connexes.
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Agregação dinâmica de tráfego com especificações de tempo e roteamento multicaminho em redes ópticas WDM / Dynamic traffic grooming with timing specifications and multipath routing in WDM optical networksSanti, Juliana de, 1982- 27 August 2018 (has links)
Orientador: Nelson Luis Saldanha da Fonseca / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-27T12:19:41Z (GMT). No. of bitstreams: 1
Santi_Julianade_D.pdf: 2864937 bytes, checksum: 7526ed7e2e57bec4e7361a8c0f9f8b47 (MD5)
Previous issue date: 2015 / Resumo: As redes ópticas com multiplexação por comprimento de onda (WDM) permitem a transmissão de grande volume de dados através de múltiplos canais com capacidade de transmissão de vários Gbps. Entretanto, as demandas por banda passante dos fluxos IPs são significativamente inferior à capacidade disponível em cada canal WDM. Para lidar com esta disparidade e utilizar de forma eficiente a banda disponível, é necessária a transmissão simultânea de vários fluxos em um caminho óptico, chamado de agregação de tráfego. Especificações de qualidade de serviço dos fluxos devem, também, ser consideradas nas decisões de agregação de tráfego. Ademais, aplicações emergentes podem demandar largura de banda superior à capacidade de um comprimento de onda, sendo necessário utilizar vários caminhos ópticos (roteamento multicaminho) para provisionar tais fluxos. Além disso, a expansão da infraestrutura e utilização das redes WDM têm elevado o consumo de energia, causando impactos econômicos e ambientais. Estas questões têm desafiado e motivado pesquisadores a encontrar alternativas para aprimorar as transmissões nas redes ópticas WDM, o que inclui a agregação de tráfego e o roteamento multicaminho. Nesta tese, abordam-se diversos problemas em agregação de tráfego e roteamento multicaminho em redes ópticas WDM. Foram desenvolvidos e validados algoritmos pelo menos tão eficientes quanto algoritmos existentes na literatura. Propõe-se um algoritmo de agregação de tráfego que considera a duração das conexões e a banda disponível. Para atender demandas superiores à capacidade de um comprimento de onda, desenvolveu-se um algoritmo que considera a duração do fluxo, divide-o em subfluxos e os transmite em múltiplos canais. Para este algoritmo, foi proposta uma versão aproximada visando reduzir o tempo de resolução do problema. Introduziu-se, também, um algoritmo que indica a postergação do momento de início da transmissão das conexões a fim de agregar lotes de conexões. Para reduzir o consumo de energia, foram desenvolvidas duas estratégias, de roteamento multicaminho e reroteamento, que levam em consideração o consumo de energia das operações envolvidas na transmissão da conexão / Abstract: The wavelength division multiplexing (WDM) optical networks allow the transmission of large volume of data through multiple channels with severals Gbps of transmission capacity. However, the demand for bandwidth of IP flows are significantly lower than the available capacity in each WDM channel. To address this disparity and make efficient use of the available bandwidth, it is necessary to transmit simultaneously multiple streams in lightpath, called traffic grooming. The quality of service specifications inherent to connections should also be considered in the traffic aggregation decisions. Moreover, emerging applications can request bandwidth greater than the capacity of a wavelength, which require several lightpaths (multipath routing) to establish such connections. In addition, infrastructure expansion and use of WDM networks have increased the energy consumption, leading to economic and environmental concerns. These issues have challenged and motivated researchers to find alternatives to enhance transmissions in WDM optical networks, which includes the traffic grooming and multipath routing. This thesis addresses several problems in traffic grooming and multipath routing in WDM optical networks. For each problem algorithms were developed and validated that are at least as efficient as existing algorithms in the literature. It was proposed a traffic grooming algorithm that considers the duration of connections and the available bandwidth along the path. In order to establish connections demanding bandwidth greater than the capacity of a wavelength, it was proposed an algorithm that considers the duration of a connection and divides this connection in to substreams and transmits them on multiple wavelengths. For this algorithm, it was proposed an approximate version to reduce the run time. Moreover, it was introduced an algorithm which postpones the time to establish the connections and aggregates batch connections. In order to reduce the energy consumption, two strategies, multipath routing and rerouting, were developed that take into account the energy consumption of each operation involved in the connection transmission / Doutorado / Ciência da Computação / Doutora em Ciência da Computação
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Groupage et protection du trafic dynamique dans les réseaux WDMMetnani, Ammar 03 1900 (has links)
Avec les nouvelles technologies des réseaux optiques, une quantité de données de plus en plus grande peut être transportée par une seule longueur d'onde. Cette quantité peut atteindre jusqu’à 40 gigabits par seconde (Gbps). Les flots de données individuels quant à eux demandent beaucoup moins de bande passante. Le groupage de trafic est une technique qui permet l'utilisation efficace de la bande passante offerte par une longueur
d'onde. Elle consiste à assembler plusieurs flots de données de bas débit en une seule
entité de données qui peut être transporté sur une longueur d'onde.
La technique demultiplexage en longueurs d'onde (Wavelength Division Multiplexing WDM) permet de transporter plusieurs longueurs d'onde sur une même fibre. L'utilisation des deux techniques : WDM et groupage de trafic, permet de transporter une quantité de données de l'ordre de terabits par seconde (Tbps) sur une même fibre optique. La protection du trafic dans les réseaux optiques devient alors une opération très vitale pour ces
réseaux, puisqu'une seule panne peut perturber des milliers d'utilisateurs et engendre des pertes importantes jusqu'à plusieurs millions de dollars à l'opérateur et aux utilisateurs du réseau. La technique de protection consiste à réserver une capacité supplémentaire pour acheminer le trafic en cas de panne dans le réseau.
Cette thèse porte sur l'étude des techniques de groupage et de protection du trafic en
utilisant les p-cycles dans les réseaux optiques dans un contexte de trafic dynamique. La majorité des travaux existants considère un trafic statique où l'état du réseau ainsi que le trafic sont donnés au début et ne changent pas. En plus, la majorité de ces travaux utilise des heuristiques ou des méthodes ayant de la difficulté à résoudre des instances de grande taille.
Dans le contexte de trafic dynamique, deux difficultés majeures s'ajoutent aux problèmes
étudiés, à cause du changement continuel du trafic dans le réseau. La première est due au fait que la solution proposée à la période précédente, même si elle est optimisée, n'est plus nécessairement optimisée ou optimale pour la période courante, une nouvelle
optimisation de la solution au problème est alors nécessaire. La deuxième difficulté est
due au fait que la résolution du problème pour une période donnée est différente de sa
résolution pour la période initiale à cause des connexions en cours dans le réseau qui ne
doivent pas être trop dérangées à chaque période de temps.
L'étude faite sur la technique de groupage de trafic dans un contexte de trafic dynamique
consiste à proposer différents scénarios pour composer avec ce type de trafic, avec comme objectif la maximisation de la bande passante des connexions acceptées à chaque période de temps. Des formulations mathématiques des différents scénarios considérés pour le problème de groupage sont proposées.
Les travaux que nous avons réalisés sur le problème de la protection considèrent deux types de p-cycles, ceux protégeant les liens (p-cycles de base) et les FIPP p-cycles (p-cycles protégeant les chemins). Ces travaux ont consisté d’abord en la proposition de différents scénarios pour gérer les p-cycles de protection dans un contexte de trafic
dynamique. Ensuite, une étude sur la stabilité des p-cycles dans un contexte de trafic dynamique a été faite. Des formulations de différents scénarios ont été proposées et les méthodes de résolution utilisées permettent d’aborder des problèmes de plus grande taille que ceux présentés dans la littérature. Nous nous appuyons sur la méthode de génération de colonnes pour énumérer implicitement les cycles les plus prometteurs.
Dans l'étude des p-cycles protégeant les chemins ou FIPP p-cycles, nous avons proposé
des formulations pour le problème maître et le problème auxiliaire. Nous avons utilisé une méthode de décomposition hiérarchique du problème qui nous permet d'obtenir de meilleurs résultats dans un temps raisonnable. Comme pour les p-cycles de base,
nous avons étudié la stabilité des FIPP p-cycles dans un contexte de trafic dynamique.
Les travaux montrent que dépendamment du critère d'optimisation, les p-cycles de base
(protégeant les liens) et les FIPP p-cycles (protégeant les chemins) peuvent être très
stables. / With new technologies in optical networking, an increasing quantity of data can be carried
by a single wavelength. This amount of data can reach up to 40 gigabits per second (Gbps). Meanwhile, the individual data flows require much less bandwidth. The traffic grooming is a technique that allows the efficient use of the bandwidth offered by a wavelength.
It consists of assembling several low-speed data streams into a single data entity that can be carried on a wavelength.
The wavelength division multiplexing (WDM) technique allows carrying multiple wavelengths on a single fiber. The use of the two techniques,WDMand traffic grooming, allows carrying a quantity of data in the order of terabits per second (Tbps) over a single optical fiber. Thus, the traffic protection in optical networks becomes an operation very vital for these networks, since a single failure can disrupt thousands of users and may result in several millions of dollars of lost revenue to the operator and the network users.
The survivability techniques involve reserving additional capacity to carry traffic in case of a failure in the network.
This thesis concerns the study of the techniques of grooming and protection of traffic using p-cycles in optical networks in a context of dynamic traffic. Most existing work considers a static traffic where the network status and the traffic are given at the beginning and do not change. In addition, most of these works concerns heuristic algorithms or methods suffering from critical lack of scalability.
In the context of dynamic traffic, two major difficulties are added to the studied problems, because of the continuous change in network traffic. The first is due to the fact
that the solution proposed in the previous period, even if optimal, does not necessarily
remain optimal in the current period. Thus, a re-optimization of the solution to the problem is required. The second difficulty is due to the fact that the solution of the
problem for a given period is different from its solution for the initial period because of the ongoing connections in the network that should not be too disturbed at each time
period.
The study done on the traffic grooming technique in the context of dynamic traffic consists of proposing different scenarios for dealing with this type of traffic, with the
objective of maximizing the bandwidth of the new granted connections at each time period.
Mathematical formulations of the different considered scenarios for the grooming problem are proposed.
The work we have done on the problem of protection considers two types of p-cycles,
those protecting links and FIPP p-cycles (p-cycle protecting paths). This work consisted
primarily on the proposition of different scenarios for managing protection p-cycles in
a context of dynamic traffic. Then, a study on the stability of cycles in the context of dynamic traffic was done. Formulations of different scenarios have been proposed and the proposed solution methods allow the approach of larger problem instances than those reported in the literature. We rely on the method of column generation to implicitly
enumerate promising cycles.
In the study of path protecting p-cycles or FIPP p-cycles, we proposed mathematical formulations for the master and the pricing problems. We used a hierarchical decomposition of the problem which allows us to obtain better results in a reasonable time. As for the basic p-cycles, we studied the stability of FIPP p-cycles in the context of dynamic traffic. The work shows that depending on the optimization criterion, the basic p-cycles (protecting the links) and FIPP p-cycles (protecting paths) can be very stable.
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Arquitetura de nós e engenharia de tráfego em redes ópticas / Nodes architecture and traffic engineering in optical networksAlmeida Neto, Helvécio Moreira de 25 September 2009 (has links)
A interligação de várias redes de telecomunicação ampliou a cobertura, mas tornou a operabilidade entre elas complexa, principalmente por causa da arquitetura resultante, formada por várias camadas. Estas camadas lidam com protocolos e taxas de transmissão diferentes e com sinais elétricos e ópticos. Diante desse cenário, a alternativa usual de expandir os recursos proporcionalmente ao crescimento da demanda é inviável devido ao elevado custo. Assim, soluções eficientes que agregam os benefícios das tecnologias ópticas e eletrônicas na arquitetura de nós e no gerenciamento de tráfego tornaram-se uma necessidade importante no projeto, expansão e gerenciamento de redes de telecomunicação. Os nós que permitem a comutação de tráfego na camada óptica e eletrônica e a agregação de tráfego em várias granularidades têm sido empregados para fazer o melhor uso possível dos recursos disponíveis nas redes. Esses nós são conhecidos na literatura como MG-OXCs. Nessa pesquisa, foi proposta uma abordagem dos nós MG-OXCs de uma e três camadas com a inclusão de recursos como conversão de comprimento de onda e agregação de tráfego. Também foi proposto um método de cálculo do custo desses nós baseado no volume de utilização das portas. Posteriormente foram inseridos fatores de degradação do sinal óptico para a análise da camada física de redes com os nós MGOXCs. Adicionalmente, para o gerenciamento de tráfego, foi proposto um esquema de escolha de comprimentos de onda chamado de canal específico e um esquema de monitoramento baseado na intensidade de tráfego. A meta principal é a redução da probabilidade de bloqueio de solicitação de conexão. Em redes ópticas, os modelos de nós propostos conseguem diminuir o número de portas dos nós comutadores tradicionais além de realizar a comutação de tráfego de conexões de diferentes valores de largura de banda. O esquema do canal específico consegue melhorar a utilização da largura de banda dos comprimentos de onda e diminui a probabilidade de bloqueio e o esquema do monitoramento diminui o número de conexões bloqueadas devido ao aumento dos recursos. Resultados numéricos apresentados demonstram a potencialidade dos algoritmos propostos para gerenciar recursos e rotear o tráfego das redes de telecomunicação. / Integrating telecommunication networks has enlarged the coverage, but has made operations more complex, mainly because of the architecture, formed by various layers. These layers deal with different protocols and transmission rates, as well as electrical and optical signals. The usual alternative of expanding the resources proportionally to the demand is impractical due to the high cost. Therefore, efficient solutions which add to the benefits of optical and electronic technology in node architecture and traffic management are essential in the design, expansion and management of telecommunications networks. The nodes that enable traffic switching in the optical and electronic layer and traffic grooming have been used to make the best use of the available resources in the networks. These nodes are known as MG-OXCs. In this research, an approach based on MG-OXCs was proposed with one and three layers, which include the wavelength conversion and traffic grooming. Additionally, a method to calculate the node costs based on their use of ports was proposed. The work also considered optical signal impairments in order to analyze the network physical layer with MG-OXCs nodes. For the purpose of traffic management, a scheme which sets specific wavelengths for different bandwidths and a scheme which monitors the flow of traffic were proposed. The main aim is to reduce the blocking probability of connection requests. In optical networks, the node models proposed are able to reduce the number of ports used in usual optical cross connects and switch the traffic connections using different bandwidths. The scheme of setting specific wavelengths for different bandwidths improves the bandwidth use and the blocking probability. The scheme which monitors the flow of traffic achieves blocking probability reduction due to the increase in resources. The numerical results presented show the feasibility of the proposed algorithms to manage resources and switch traffic in telecommunication networks.
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Groupage et protection du trafic dynamique dans les réseaux WDMMetnani, Ammar 03 1900 (has links)
Avec les nouvelles technologies des réseaux optiques, une quantité de données de plus en plus grande peut être transportée par une seule longueur d'onde. Cette quantité peut atteindre jusqu’à 40 gigabits par seconde (Gbps). Les flots de données individuels quant à eux demandent beaucoup moins de bande passante. Le groupage de trafic est une technique qui permet l'utilisation efficace de la bande passante offerte par une longueur
d'onde. Elle consiste à assembler plusieurs flots de données de bas débit en une seule
entité de données qui peut être transporté sur une longueur d'onde.
La technique demultiplexage en longueurs d'onde (Wavelength Division Multiplexing WDM) permet de transporter plusieurs longueurs d'onde sur une même fibre. L'utilisation des deux techniques : WDM et groupage de trafic, permet de transporter une quantité de données de l'ordre de terabits par seconde (Tbps) sur une même fibre optique. La protection du trafic dans les réseaux optiques devient alors une opération très vitale pour ces
réseaux, puisqu'une seule panne peut perturber des milliers d'utilisateurs et engendre des pertes importantes jusqu'à plusieurs millions de dollars à l'opérateur et aux utilisateurs du réseau. La technique de protection consiste à réserver une capacité supplémentaire pour acheminer le trafic en cas de panne dans le réseau.
Cette thèse porte sur l'étude des techniques de groupage et de protection du trafic en
utilisant les p-cycles dans les réseaux optiques dans un contexte de trafic dynamique. La majorité des travaux existants considère un trafic statique où l'état du réseau ainsi que le trafic sont donnés au début et ne changent pas. En plus, la majorité de ces travaux utilise des heuristiques ou des méthodes ayant de la difficulté à résoudre des instances de grande taille.
Dans le contexte de trafic dynamique, deux difficultés majeures s'ajoutent aux problèmes
étudiés, à cause du changement continuel du trafic dans le réseau. La première est due au fait que la solution proposée à la période précédente, même si elle est optimisée, n'est plus nécessairement optimisée ou optimale pour la période courante, une nouvelle
optimisation de la solution au problème est alors nécessaire. La deuxième difficulté est
due au fait que la résolution du problème pour une période donnée est différente de sa
résolution pour la période initiale à cause des connexions en cours dans le réseau qui ne
doivent pas être trop dérangées à chaque période de temps.
L'étude faite sur la technique de groupage de trafic dans un contexte de trafic dynamique
consiste à proposer différents scénarios pour composer avec ce type de trafic, avec comme objectif la maximisation de la bande passante des connexions acceptées à chaque période de temps. Des formulations mathématiques des différents scénarios considérés pour le problème de groupage sont proposées.
Les travaux que nous avons réalisés sur le problème de la protection considèrent deux types de p-cycles, ceux protégeant les liens (p-cycles de base) et les FIPP p-cycles (p-cycles protégeant les chemins). Ces travaux ont consisté d’abord en la proposition de différents scénarios pour gérer les p-cycles de protection dans un contexte de trafic
dynamique. Ensuite, une étude sur la stabilité des p-cycles dans un contexte de trafic dynamique a été faite. Des formulations de différents scénarios ont été proposées et les méthodes de résolution utilisées permettent d’aborder des problèmes de plus grande taille que ceux présentés dans la littérature. Nous nous appuyons sur la méthode de génération de colonnes pour énumérer implicitement les cycles les plus prometteurs.
Dans l'étude des p-cycles protégeant les chemins ou FIPP p-cycles, nous avons proposé
des formulations pour le problème maître et le problème auxiliaire. Nous avons utilisé une méthode de décomposition hiérarchique du problème qui nous permet d'obtenir de meilleurs résultats dans un temps raisonnable. Comme pour les p-cycles de base,
nous avons étudié la stabilité des FIPP p-cycles dans un contexte de trafic dynamique.
Les travaux montrent que dépendamment du critère d'optimisation, les p-cycles de base
(protégeant les liens) et les FIPP p-cycles (protégeant les chemins) peuvent être très
stables. / With new technologies in optical networking, an increasing quantity of data can be carried
by a single wavelength. This amount of data can reach up to 40 gigabits per second (Gbps). Meanwhile, the individual data flows require much less bandwidth. The traffic grooming is a technique that allows the efficient use of the bandwidth offered by a wavelength.
It consists of assembling several low-speed data streams into a single data entity that can be carried on a wavelength.
The wavelength division multiplexing (WDM) technique allows carrying multiple wavelengths on a single fiber. The use of the two techniques,WDMand traffic grooming, allows carrying a quantity of data in the order of terabits per second (Tbps) over a single optical fiber. Thus, the traffic protection in optical networks becomes an operation very vital for these networks, since a single failure can disrupt thousands of users and may result in several millions of dollars of lost revenue to the operator and the network users.
The survivability techniques involve reserving additional capacity to carry traffic in case of a failure in the network.
This thesis concerns the study of the techniques of grooming and protection of traffic using p-cycles in optical networks in a context of dynamic traffic. Most existing work considers a static traffic where the network status and the traffic are given at the beginning and do not change. In addition, most of these works concerns heuristic algorithms or methods suffering from critical lack of scalability.
In the context of dynamic traffic, two major difficulties are added to the studied problems, because of the continuous change in network traffic. The first is due to the fact
that the solution proposed in the previous period, even if optimal, does not necessarily
remain optimal in the current period. Thus, a re-optimization of the solution to the problem is required. The second difficulty is due to the fact that the solution of the
problem for a given period is different from its solution for the initial period because of the ongoing connections in the network that should not be too disturbed at each time
period.
The study done on the traffic grooming technique in the context of dynamic traffic consists of proposing different scenarios for dealing with this type of traffic, with the
objective of maximizing the bandwidth of the new granted connections at each time period.
Mathematical formulations of the different considered scenarios for the grooming problem are proposed.
The work we have done on the problem of protection considers two types of p-cycles,
those protecting links and FIPP p-cycles (p-cycle protecting paths). This work consisted
primarily on the proposition of different scenarios for managing protection p-cycles in
a context of dynamic traffic. Then, a study on the stability of cycles in the context of dynamic traffic was done. Formulations of different scenarios have been proposed and the proposed solution methods allow the approach of larger problem instances than those reported in the literature. We rely on the method of column generation to implicitly
enumerate promising cycles.
In the study of path protecting p-cycles or FIPP p-cycles, we proposed mathematical formulations for the master and the pricing problems. We used a hierarchical decomposition of the problem which allows us to obtain better results in a reasonable time. As for the basic p-cycles, we studied the stability of FIPP p-cycles in the context of dynamic traffic. The work shows that depending on the optimization criterion, the basic p-cycles (protecting the links) and FIPP p-cycles (protecting paths) can be very stable.
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