Les nouvelles applications sur Internet nécessitent des garanties de qualité de service (QoS) de la part du réseau. Nous nous intéressons à deux paramètres de QoS : le temps de réponse et la gigue de bout-en-bout. Nous proposons un ordonnancement, noté FP/DP, à base de priorités fixes (FP), départageant les paquets ex aequo selon leurs priorités dynamiques (DP). La priorité fixe d'un flux reflète son degré d'importance et sa priorité dynamique est un paramètre temporel. FP/FIFO et FP/EDF sont deux exemples d'ordonnancement FP/DP. Nous déterminons des bornes déterministes sur les paramètres de QoS considérés, en utilisant l'approche par trajectoire. En monoprocesseur, nous améliorons les résultats existants et prouvons que FP/EDF domine FP/FIFO sous certaines conditions. En distribué, nous apportons de nouveaux résultats et montrons que l'approche par trajectoire est beaucoup moins pessimiste que l'approche holistique. Nos résultats sont appliqués dans une architecture DiffServ/MPLS.

Les noves tecnologies a la xarxa ens permeten transportar, cada cop més, grans volums d' informació i trànsit de xarxa amb diferents nivells de prioritat. En aquest escenari, on s'ofereix una millor qualitat de servei, les conseqüències d'una fallada en un enllaç o en un node esdevenen més importants. Multiprotocol Lavel Switching (MPLS), juntament amb l'extensió a MPLS generalitzat (GMPLS), proporcionen mecanismes ràpids de recuperació de fallada establint camins, Label Switch Path (LSPs), redundants per ser utilitzats com a camins alternatius. En cas de fallada podrem utilitzar aquests camins per redireccionar el trànsit. El principal objectiu d'aquesta tesi ha estat millorar alguns dels actuals mecanismes de recuperació de fallades MPLS/GMPLS, amb l'objectiu de suportar els requeriments de protecció dels serveis proporcionats per la nova Internet. Per tal de fer aquesta avaluació s'han tingut en compte alguns paràmetres de qualitat de protecció com els temps de recuperació de fallada, les pèrdues de paquets o el consum de recursos.En aquesta tesi presentem una completa revisió i comparació dels principals mètodes de recuperació de fallada basats en MPLS. Aquest anàlisi inclou els mètodes de protecció del camí (backups globals, backups inversos i protecció 1+1), els mètodes de protecció locals i els mètodes de protecció de segments. També s'ha tingut en compte l'extensió d'aquests mecanismes a les xarxes òptiques mitjançant el pla de control proporcionat per GMPLS.En una primera fase d'aquest treball, cada mètode de recuperació de fallades és analitzat sense tenir en compte restriccions de recursos o de topologia. Aquest anàlisi ens dóna una primera classificació dels millors mecanismes de protecció en termes de pèrdues de paquets i temps de recuperació. Aquest primer anàlisi no és aplicable a xarxes reals. Per tal de tenir en compte aquest nou escenari, en una segona fase, s'analitzen els algorismes d'encaminament on sí tindrem en compte aquestes limitacions i restriccions de la xarxa. Es presenten alguns dels principals algorismes d'encaminament amb qualitat de servei i alguna de les principals propostes d'encaminament per xarxes MPLS. La majoria dels actual algorismes d'encaminament no tenen en compte l'establiment de rutes alternatives o utilitzen els mateixos objectius per seleccionar els camins de treball i els de protecció. Per millorar el nivell de protecció introduïm i formalitzem dos nous conceptes: la Probabilitat de fallada de la xarxa i l'Impacte de fallada. Un anàlisi de la xarxa a nivell físic proporciona un primer element per avaluar el nivell de protecció en termes de fiabilitat i disponibilitat de la xarxa. Formalitzem l'impacte d'una fallada, quant a la degradació de la qualitat de servei (en termes de retard i pèrdues de paquets). Expliquem la nostra proposta per reduir la probabilitat de fallada i l'impacte de fallada. Per últim fem una nova definició i classificació dels serveis de xarxa segons els valors requerits de probabilitat de fallada i impacte.Un dels aspectes que destaquem dels resultats d'aquesta tesi és que els mecanismes de protecció global del camí maximitzen la fiabilitat de la xarxa, mentre que les tècniques de protecció local o de segments de xarxa minimitzen l'impacte de fallada. Per tant podem assolir mínim impacte i màxima fiabilitat aplicant protecció local a tota la xarxa, però no és una proposta escalable en termes de consum de recursos. Nosaltres proposem un mecanisme intermig, aplicant protecció de segments combinat amb el nostre model d'avaluació de la probabilitat de fallada. Resumint, aquesta tesi presenta diversos mecanismes per l'anàlisi del nivell de protecció de la xarxa. Els resultats dels models i mecanismes proposats milloren la fiabilitat i minimitzen l'impacte d'una fallada en la xarxa. / New network technology enables increasingly higher volumes of information to be carried. Various types of mission-critical, higher-priority traffic are now transported over these networks. In this scenario, when offering better quality of service, the consequences of a fault in a link or node become more pronounced. Multiprotocol Label Switching (MPLS) and the extended Generalized MPLS (GMPLS) provide fast mechanisms for recovery from failures by establishing redundant Label Switch Paths as backup paths. With these backups, traffic can always be redirected in case of failure. The main objective of this thesis is to improve some of the current MPLS/GMPLS fault recovery methods, in order to support the protection requirements of the new Internet services. Some parameters, such as fault recovery time, packet loss or resource consumption, all within the scope of this quality of protection, are considered. In this thesis a review and detailed comparison of the MPLS fault recovery methods are presented. Path protection methods (global backups, reverse backups and 1+1 methods), as well as segment protection and local methods are included in this analysis. The extension of these mechanisms to optical networks using GMPLS control plane is also taken into account.In the first phase MPLS fault recovery methods are analyzed without taking into account resource or network topology constraints. This analysis reported a first classification of the best protection methods in terms of packet loss and recovery time. This first analysis cannot be applied to real networks. In real networks, bandwidth or network topology constraints can force a change in the a priori optimal protection choice. In this new scenario, current routing algorithms must be analyzed. The main aspects of the QoS routing methods are introduced, and some of these mechanisms are described and compared. QoS routing algorithms do not include protection as a main objective and, moreover, the same QoS objectives for selecting the working path are used for selecting the backup path. In order to evaluate the quality of protection, two novel concepts are introduced and analyzed: the network failure probability and the failure impact. The physical network provides an initial value of the network protection level in terms of network reliability and availability. A proposal to evaluate network reliability is introduced, and a formulation to calculate the failure impact (the QoS degradation in terms of packet loss and delay) is presented. A proposal to reduce the failure probability and failure impact as well as the enhancement of some current routing algorithms in order to achieve better protection are explained. A review of the traffic services protection requirements and a new classification, based on the failure probability and failure impact values, is also provided in this work.Results show that path protection schemes improve network reliability. Segment/local protection schemes reduce the network failure impact. Minimum impact with maximum reliability can be achieved using local protection throughout the entire network. However, it is not scalable in terms of resource consumption. In this case our failure probability evaluation model can be used to minimize the required resources. Results demonstrate the reduction of the failure impact combining segment protection and our network reliability evaluation model in different network scenarios.In summary, an in-depth analysis is carried out and a formulation to evaluate the network protection level is presented. This evaluation is based on network reliability maximization and failure impact reduction in terms of QoS degradation. A scalable proposal in terms of resource consumption, detailed and experimentally analyzed, offers the required level of protection in different network scenarios for different traffic services.

L'objectif de ce travail de thèse dans un premier temps est l'évaluation de performances des modèles de routage multi-chemins pour l'ingénierie de trafic et l'équilibrage de charge sur un réseau de type IP/MPLS (MPLS-TE). Nous comparons la capacité de ces modèles à équilibrer la charge du réseau tout en faisant de la différentiation de trafic. Nous les appliquons sur des grandes topologies générées par le générateur automatique des topologies BRITE, qui s'approchent en forme et en complexité du réseau réel. Nous mesurons ainsi l'impact de leur complexité respective et donc la capacité à les déployer sur des réseaux de grande taille (scalabilité). Dans un second temps, l'objectif est de proposer un concept de modélisation générale d'un réseau à commutations par paquets. Ce modèle est établi sur la base de la théorie différentielle de trafic et la théorie des files d'attente, tout en utilisant des approches graphiques. Le but est d'estimer l'état de charge du réseau et de ses composants (routeurs, liens, chemins). Ensuite, en fonction de ça, nous développons des approches de contrôle de congestion et commande sur l'entrée améliorant les techniques de routage adaptatif et l'équilibrage de charge dans les réseaux IP/MPLS / In This work, firstly we present and evaluate the behavior of multipath routing models for the DS-TE (DiffSev aware MPLS traffic Engineering) called PEMS and LBWDP. To clarify network topologies and routing models that are suitable for MPLS Traffic Engineering, we evaluate them from the viewpoint of network scalability and end-to-end quality. Using a network topology generated by BRITE, that has many alternative paths, we applied these models on a huge topology that correspond to real network. This can provide a real simulation for the internet and gives a good evaluation for the end-to-end quality and the network use.Secondly, the aim of this work is to propose a general model for Packet switching networks. This model is established on the traffic differential theory and the Queuing theory, while using graphic approaches. The aim of this model is to calculate the network use state and its components (router, link, path...). Then, we develop control and command approaches in the entry of network to improve an adaptive routing plan and load balancing in IP/MPLS networks

Network management plays a vital role to keep a network and its application work e ciently. The network management in MANETs is a crucial and the challenging task, as these networks are characterized by dynamic environment and the scarcity of resources. There are various existing approaches for network management in MANETs. The Ad hoc Network Management Protocol (ANMP) has been one of the rst e orts and introduced an SNMP-based solution for MANETs. An alternative SNMP-based solu-tion is proposed by GUERRILLA Management Architecture (GMA). Due to self-organizing characteristic feature of MANETs, the management task has to be distributed. Policy-based network management relatively o ers this feature, by executing and applying policies pre-viously de ned by network manager. Otherwise, the complexity of realization and control becomes di cult Most of the works address the current status of the MANET to take the network man-agement decisions. Currently, MANETs addresses the dynamic and intelligent decisions by considering the present situation and all related history information of nodes into consid-eration. In this connection we have proposed a network management system using agents (NMSA) for MANETs, resolving major issues like, node monitoring, location management, resource management and QoS management. Solutions to these issues are discussed as inde-pendent protocols, and are nally combined into a single network management system, i.e., NMSA. Agents are autonomous, problem-solving computational entities capable of performing e ective operation in dynamic environments. Agents have cooperation, intelligence, and mobility characteristics as advantages. The agent platforms provide the di erent services to agents, like execution, mobility, communication, security, tracking, persistence and directory etc. The platform execution environment allows the agents to run, and mobility service allows them to travel among the di erent execution environments. The entire management task will be delegated to agents, which then executes the management logic in a distributed and autonomous fashion. In our work we used the static and mobile agents to nd some solutions to the management issues in a MANET. We have proposed a node monitoring protocol for MANETs, which uses both static agent (SA) and mobile agents (MA), to monitor the nodes status in the network. It monitors the gradational energy loss, bu er, bandwidth, and the mobility of nodes running with low to high load of mobile applications. Protocol assumes the MANET is divided into zones and sectors. The functioning of the protocol is divided into two segments, The NMP main segment, which runs at the chosen resource rich node (RRN) at the center of a MANET, makes use of SA which resides at same RRN, and the NMP subsegment which runs in the migrated MAs at the other nodes. Initially SA creates MAs and dispatches one MA to each zone, in order to monitor health conditions and mobility of nodes of the network. MAs carrying NMP subsegment migrates into the sector of a respective zone, and monitors the resources such as bandwidth, bu er, energy level and mobility of nodes. After collecting the nodes information and before moving to next sector they transfer collected information to SA respectively. SA in turn coordinates with other modules to analyze the nodes status information. We have validated the protocol by performing the conformance testing of the proposed node monitoring protocol (NMP) for MANETs. We used SDL to obtain MSCs, that repre-sents the scenario descriptions by sequence diagrams, which in turn generate test cases and test sequences. Then TTCN-3 is used to execute the test cases with respect to generated test sequences to know the conformance of protocol against the given speci cation. We have proposed a location management protocol for locating the nodes of a MANET, to maintain uninterrupted high-quality service for distributed applications by intelligently anticipating the change of location of its nodes by chosen neighborhood nodes. The LMP main segment of the protocol, which runs at the chosen RRN located at the center of a MANET, uses SA to coordinate with other modules and MA to predict the nodes with abrupt movement, and does the replacement with the chosen nodes nearby which have less mobility. We have proposed a resource management protocol for MANETs, The protocol makes use of SA and MA for fair allocation of resources among the nodes of a MANET. The RMP main segment of the protocol, which runs at the chosen RRN located at the center of a MANET, uses SA to coordinate with other modules and MA to allocate the resources among the nodes running di erent applications based on priority. The protocol does the distribution and parallelism of message propagation (mobile agent with information) in an e cient way in order to minimize the number of message passing with reduction in usage of network resources and improving the scalability of the network. We have proposed a QoS management protocol for MANETs, The QMP main segment of the protocol, which runs at the chosen RRN located at the center of a MANET, uses SA to coordinate with other modules and MA to allocate the resources among the nodes running di erent applications based on priority over QoS. Later, to reallocate the resources among the priority applications based on negotiation and renegotiation for varying QoS requirements. The performance testing of the protocol is carried out using TTCN-3. The generated test cases for the de ned QoS requirements are executed with TTCN-3, for testing of the associated QoS parameters, which leads to performance testing of proposed QoS management protocol for MANETs. We have combined the developed independent protocols for node monitoring, location management, resource management, and QoS management, into one single network management system called Network Management System using Agents (NMSA) for MANETs and tested in di erent environments. We have implemented NMSA on Java Agent development environment (JADE) Platform. Our developed network management system is a distributed system. It is basically divided into two parts, the Network Management Main Segment and other is Network Management Subsegment. A resource rich node (RRN) which is chosen at the center of a MANET where the Main segment of NMSA is located, and it controls the management activities. The other mobile nodes in the network will run MA which has the subsegments of NMSA. The network management system, i.e., the developed NMSA, has Network manage-ment main (NMSA main), Zones and sector segregation scheme, NMP, LMP, RMP, QMP main segments at the RRN along with SA deployed. The migrated MA at mobile node has subsegments of NMP, LMP, RMP, and QMP respectively. NMSA uses two databases, namely, Zones and sectors database and Node history database. Implementation of the proposed work is carried out in a con ned environment with, JDK and JADE installed on network nodes. The launched platform will have AMS and DF automatically generated along with MTP for exchange of message over the channel. Since only one JVM, which is installed, will executes on many hosts in order to provide the containers for agents on those hosts. It is the environment which o ered, for execution of agents. Many agents can be executed in parallel. The main container, is the one which has AMS and DF, and RMI registry are part of JADE environment which o ers complete run time environment for execution of agents. The distribution of the platform on many containers of nodes is shown in Fig. 1. The NMSA is based on Linux platform which provides distributed environment, and the container of JADE could run on various platforms. JAVA is the language used for code development. A middle layer, i.e., JDBC (java database connection) with SQL provides connectivity to the database and the application. The results of experiments suggest that the proposed protocols are e ective and will bring, dynamism and adaptiveness to the applied system and also reduction in terms network overhead (less bandwidth consumption) and response time.

We consider optimal power allocation policies for a single server, multiuser wireless communication system. The transmission channel may experience multipath fading. We obtain very efficient, low computational complexity algorithms which minimize power and ensure stability of the data queues. We also obtain policies when the users may have mean delay constraints. If the power required is a linear function of rate then we exploit linearity and obtain linear programs with low complexity. We also provide closed-form optimal power policies when there is a hard deadline delay constraint. Later on, we also extend single hop results to multihop networks. First we consider the case, when the transmission rate is a linear function of power. We provide low complexity algorithms for joint routing, scheduling and power control which ensure stability of the queues, certain minimum rates, end-to-end hard deadlines, and/or upper bounds on the end-to-end mean delays. Further we extend these results to the multihop networks where the power is a general monotonically increasing function of rate. For our algorithms, we also provide rates of convergence to the stationary distributions for the queue length process and also approximate end-to-end mean delays. Finally, we provide computationally efficient algorithms that minimize the total power when there is a end-to-end hard deadline delay constraint.

Made available in DSpace on 2014-12-17T14:54:54Z (GMT). No. of bitstreams: 1 ViegasJuniorR_TESE.pdf: 2611835 bytes, checksum: 668f48088b8bbf9b308f0cb4b0dd4535 (MD5) Previous issue date: 2010-02-11 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This thesis proposes the specification and performance analysis of a real-time communication mechanism for IEEE 802.11/11e standard. This approach is called Group Sequential Communication (GSC). The GSC has a better performance for dealing with small data packets when compared to the HCCA mechanism by adopting a decentralized medium access control using a publish/subscribe communication scheme. The main objective of the thesis is the HCCA overhead reduction of the Polling, ACK and QoS Null frames exchanged between the Hybrid Coordinator and the polled stations. The GSC eliminates the polling scheme used by HCCA scheduling algorithm by using a Virtual Token Passing procedure among members of the real-time group to whom a high-priority and sequential access to communication medium is granted. In order to improve the reliability of the mechanism proposed into a noisy channel, it is presented an error recovery scheme called second chance algorithm. This scheme is based on block acknowledgment strategy where there is a possibility of retransmitting when missing real-time messages. Thus, the GSC mechanism maintains the real-time traffic across many IEEE 802.11/11e devices, optimized bandwidth usage and minimal delay variation for data packets in the wireless network. For validation purpose of the communication scheme, the GSC and HCCA mechanisms have been implemented in network simulation software developed in C/C++ and their performance results were compared. The experiments show the efficiency of the GSC mechanism, especially in industrial communication scenarios. / Esta tese prop?e a especifica??o e an?lise de desempenho de um mecanismo de comunica??o de tempo real compat?vel com o Padr?o IEEE 802.11/11e, chamado Group Sequential Communication (GSC). O GSC apresenta um melhor desempenho quando comparado ao mecanismo HCCA para tratar pequenos pacotes de dados, al?m de adotar uma abordagem descentralizada do controle de acesso ao meio baseado no conceito produtor/consumidor. O objetivo principal da proposta ? a redu??o de overheads da rede, oriundos de quadros de Polling, ACK e QoS Null trocados entre o controlador h?brido e as esta??es no HCCA padr?o. O mecanismo GSC elimina o uso de quadros de Polling utilizados pelo escalonador do HCCA, atrav?s de um procedimento de Virtual Token Passing entre os membros do grupo de tempo real, a quem ? garantida alta prioridade de acesso ao meio de forma sequencial. A fim de melhorar a confiabilidade da proposta em ambientes ruidosos ? apresentado um esquema de recupera??o de erro chamado algoritmo de segunda chance. Este esquema ? baseado em uma estrat?gia de reconhecimento em bloco das mensagens enviadas, com possibilidade de serem retransmitidas quando n?o recebidas com sucesso. Desta forma, o mecanismo GSC mant?m o tr?fego das esta??es de tempo real entre os diversos dispositivos compat?vel ao Padr?o IEEE 802.11/11e, com o uso otimizado da banda e varia??es m?nimas de atraso m?dio entre as entregas dos pacotes de dados pertencentes ? rede sem fio. Para prop?sito de valida??o da proposta, os mecanismos GSC e HCCA foram implementados atrav?s de softwares de simula??o de redes desenvolvido em C/C++ e os resultados de desempenho foram comparados. Os experimentos mostram a efici?ncia do mecanismo GSC, principalmente em cen?rios de comunica??es industriais.

Les réseaux de capteurs sans-fil sont composés de dispositifs électroniques conçus pour mesurer une grandeur physique de l’environnement dans lequel ils sont déployés et pour acheminer ces mesures à un système d’information. Dans nos travaux, nous étudions les architectures de réseau et les protocoles de communication associés afin de déterminer les configurations adéquates à un scénario de réseau de capteurs pour la Ville Intelligente. Après avoir recensé les applications et leurs exigences de Qualité de Service attendue, nous avons construit des modèles analytiques permettant de comparer les différentes familles de protocoles MAC en terme de taux de livraison et de consommation d’énergie. Ces travaux permettent ainsi de motiver le choix d’un protocole synchrone ou asynchrone, à contention ou à accès direct, en fonction du scénario applicatif et du déploiement de réseau considéré : longue portée ou multi-sauts. Sur la base des résultats de cette étude, nous proposons ensuite un ensemble d’optimisation des protocoles de communication permettant d’améliorer la Qualité de Service et la dépense énergétique des compteurs. Nous proposons une méthode d’accès au médium de communication permettant l’allocation de plusieurs instants de transmission en une phase unique de tournoi. Cette optimisation vise à réduire le pôle de consommation majoritaire des réseaux multi-sauts, tel qu’identifié dans l’étude précédente. Le protocole résultant, CT-MAC, résout l’allocation de plusieurs instants de transmission en une unique phase de compétition et de manière distribuée. CT-MAC réduit ainsi la consommation d’énergie de l’arbitrage du médium. Nous proposons ensuite un mécanisme de relayage adaptatif pour l’architecture de réseau longue-portée. Le protocole, nommé SARI-MAC, est conçu de manière à pallier aux ‘trous’ de couverture que présentent les systèmes radio longue-portée lorsqu’ils sont déployés dans un habitat urbain dense. Pour cela, SARI-MAC propose d’exploiter certains nœuds du réseau, choisis pour leurs ressources en énergie, en tant que relais pour leurs voisins dont le bilan radio est insuffisant pour respecter les exigences de Qualité de Service de l’application. SARI-MAC est un protocole MAC asynchrone, initié récepteur dont les paramètres s’adaptent automatiquement aux conditions de trafic et aux contraintes de cycle d’activité imposées par la durée de vie souhaitée des nœuds capteurs et par la législation. Finalement, nous proposons un schéma de routage opportuniste appelé QOR. QOR est un protocole de routage qui tire profit des liens radio longue portée, opportunistes afin d’améliorer la fiabilité et la latence des transmissions de données dans un réseau de collecte. Pour cela, QOR propose une structure de routage combinée à un schéma d’adressage permettant d’identifier un ensemble de nœuds relais entre une source et la passerelle de collecte. / Wireless Sensors are small electronic devices made for measuring physical properties of their environment and communicating them wirelessly to an information system. In this thesis, we study existing network architectures and to devise the best-suited configuration for typical urban wireless Sensor Network use-cases. To that effect, we provide comprehensive analytical models to compare the different families of MAC protocols in terms of Delivery Rate and Energy Consumption, e.g. synchronous vs asynchronous, contention-based vs direct access etc. Headlines results a mathematical framework to devise the least energy-cost contention algorithm for a given Delivery Rate and closed-form expressions of the Energy Consumption and Delivery Rate for popular access control protocols. These results are then synthesised in a comparison study of the two prevailing urban sensors network architectures, i.e. long-range and multihop. We show that long-range sensor networks are best-suited for low-traffic and sparser network topologies while higher traffic loads and denser network topologies demand switching to a multihop network operating a synchronous MAC protocol on higher bitrate radios. Based on the analysis of the architectures best suited for each use-case scenario, i.e. low traffic loads/sparse network and high traffic loads/dense network, we identify suitable optimisations to improve the QoS performance and energy efficiency of said architectures. First, we improve on the energy efficiency of the arbitration of the medium access by defining a cascading tournament contention algorithm. This protocol, CT-MAC, resolves multiple timeslots allocation in a single, energy efficient contention tournament. Second, we propose an adaptive relaying scheme for the long-range network architecture named SARI-MAC. This scheme is an attempt to cope with coverage holes that occurs when using long-range in a dense urban habitat by letting sensor nodes relay communications of nodes whose link budgets are incompatible with the QoS requirements of the network. To that effect, we propose a receiver-initiated MAC protocol that self-adapts to the traffic condition so that the duty-cycle of relayers is kept as low as possible with respect to the load of frames to relay. Finally, we propose an opportunistic relaying scheme named QOR. QOR is a routing protocol that exploits long-range, opportunistic radio links to provide faster and more reliable transmissions. To that effect, QOR proposes a joint routing structure and addressing scheme that allows identifying a limited set of nodes than can become opportunistic relayers between a source sensor and the sink. Those nodes then follow an original cascaded acknowledgement mechanism that brings reliable acknowledgment and ensures a replication-free forwarding of the data frames.

A streaming video has features that differs from other streams: the occupation of large amount of bandwidth, and the possible variation of scenes with consequent increase (or decrease) in amount of bytes transmitted. Applications for video streaming transmission (YouTube, Vimeo, Netflix, Telecine Play, etc.) have aroused the interest of the scientific community regarding the behavior of networks. Our proposal is to measure, from a video stream, the user experience (QoE) based on arbitration QoS parameters in a controlled environment which use NetFPGA. The results of the experiments has shown the efficacy of TCP over UDP, which at the stage of choosing the most appropriate protocol for testing, showed to be ineffective to the Gigabit Ethernet rate. These experiments occurred in distinct physical topologies; only Cisco routers, with and without QoS, with and without injection of traffic generated by software iperf in the network, and using NetFPGA board set to router only with and without traffic via iperf, once the design developed to make the board work as a router does not allow QoS settings. in these scenarios, there was the need to start the client running at different times, setting their respective caches different networks so that did not coincide scenes, avoiding high bandwidth peaks in stretches with a lot of movement. / Um streaming de vídeo tem características que o difere dos demais fluxos: a ocupação de grande quantidade de banda, e a possíveis variações de cenas com consequente aumento (ou diminuição) na quantidade dos bytes transmitidos. Aplicações para transmissão de streaming de vídeo (YouTube, Vimeo, NetFlix, Telecine Play, e etc.) tem despertado o interesse da comunidade científica quanto ao comportamento das redes. Nossa proposta é correlacionar, a partir de um fluxo de vídeo, a experiência do usuário com base na arbitragem de parâmetros de QoS em ambiente controlado. O resultado dos experimentos demonstrou a eficácia do protocolo TCP sobre o UDP, que na fase da escolha do protocolo mais adequado para os testes, mostrou-se ineficiente até a taxa Gigabit Ethernet. Esses experimentos ocorreram em topologias físicas distintas; apenas com roteadores Cisco, com e sem QoS, tendo ou não injeção de tráfego gerado pelo software iPerf na rede, e usando a placa NetFPGA no modo router, apenas com e sem tráfego via iPerf, uma vez que o projeto desenvolvido para fazer a placa atuar como roteador não permite configurações de QoS. Nesses cenários, constatou-se a necessidade de iniciar a execução dos clientes em momentos diferentes, configurando seus respectivos caches de redes diferentes, para que não coincidissem as cenas, evitando altos picos de banda em trechos com muita movimentação.

Orientador: Akebo Yamakami / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-06T20:32:53Z (GMT). No. of bitstreams: 1 Resende_RaulisonAlves_D.pdf: 558127 bytes, checksum: 8c65274e70573045a52e4b1101a2c32e (MD5) Previous issue date: 2006 / Resumo: A teoria de conjuntos fuzzy provê um ferramental para desenvolver processos aproximados de raciocínio quando a informação disponível é incerta, incompleta, imprecisa ou vaga. Com as novas ferramentas emergentes na área de inteligência computacional, tais como lógicas não padronizadas, redes neurais e raciocínio simbólico, esta nova teoria é um acréscimo bem-vindo ao repertório de ferramentas tradicionais apropriadas. Neste sentido, esta tese propõe três estratégias para o provimento de qualidade de serviço em redes IP, usando lógica fuzzy. Como primeira proposta é implementado um módulo inteligente para gerenciamento da QoS por meio da criação de políticas para roteadores do tipo DiffServ. A segunda estratégia consiste em um algoritmo fuzzy que resolve o problema de roteamento baseado em restrição de tempo com mínimo custo. Esta proposta apresentou resultados satisfatórios quando comparada com a solução sem lógica fuzzy. E, por último, se propõe um controlador de admissão de conexão para tratar as informações com certo grau de incertezas em redes IP com MPLS. O controlador apresenta as seguintes vantagens: flexibilização da admissão de conexão e possibilidade de incluir mais informações da rede e do tráfego na tomada da decisão sem aumentar consideravelmente a complexidade do controlador / Abstract: Fuzzy set theory provides a machinery for carrying out approximate reasoning processes when available information is uncertain, incomplete, imprecise, or vague. With the emergence of new tools in the area of computational intelligence, such as non standard logics, neural networks, and symbolic reasoning, this new theory is a welcome addition to the repertoire of traditional appropriate tools. In this sense, this thesis proposes three different strategies to apply Fuzzy Logic to provide QoS in IP Networks. The first one is the implementation of an intelligent, policy-based module for QoS management. The module permits the creation of policies to configure QoS in routers and a practical implementation has been performed for a DiffServ router. The second strategy proposes a fuzzy algorithm to solve the problem of routing based on time restrictions with minimum costs. The results obtained from this algorithm were satisfactory when compared to similar solutions that did not involve fuzzy logic. Finally, the third strategy proposes a Connection Admission Controller to process information that contains a high level of uncertainty in IP networks over MPLS. The controller offers the following advantages: flexibility for connections admission and the possibility of including more network and traffic information in the decision making process without considerably increasing the controller complexity / Doutorado / Telecomunicações e Telemática / Doutor em Engenharia Elétrica

Submitted by Jaqueline Silva (jtas29@gmail.com) on 2014-12-12T17:31:05Z No. of bitstreams: 1 Dissertação-Victor Hugo Teles Costa-2013.pdf: 20678399 bytes, checksum: a39c778934ebe127bd74f506467fe0a3 (MD5) / Rejected by Jaqueline Silva (jtas29@gmail.com), reason: on 2014-12-12T17:31:57Z (GMT) / Submitted by Jaqueline Silva (jtas29@gmail.com) on 2014-12-12T19:42:30Z No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação-Victor Hugo Teles Costa-2013.pdf: 20678399 bytes, checksum: a39c778934ebe127bd74f506467fe0a3 (MD5) / Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2014-12-16T09:25:22Z (GMT) No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação-Victor Hugo Teles Costa-2013.pdf: 20678399 bytes, checksum: a39c778934ebe127bd74f506467fe0a3 (MD5) / Made available in DSpace on 2014-12-16T09:25:22Z (GMT). No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Dissertação-Victor Hugo Teles Costa-2013.pdf: 20678399 bytes, checksum: a39c778934ebe127bd74f506467fe0a3 (MD5) Previous issue date: 2013-12-06 / This paper presents a model based on Markov Chains and enhanced with the use of Kernel Density Estimation and of MMFM (Markov Modulated Fluid Model) in order to evaluate the performance of the transmission link in OFDMTDMA systems. For that purpose, traffic models based on the Kernel method and the MMFM with adjusted autocorrelation function are proposed. From the model implemented for the OFDM-TDMA system, it was derived equations for estimation of QoS parameters such as delay and average queue size in the buffer. The obtained results confirm that the proposed model is efficient in describing the link performance indicators. The use of MMFM to model the arrival process improves the QoS parameter estimates of the queueing model making their values very close to those of the simulation results. It was also developed an equation to the OFDMTDMA system’s service curve. Through this equation and the concept of Envelope Process, it was proposed an equation to estimate the probability of buffer overflow in OFDM-TDMA systems. The results show that the estimates of the overflow probability based on the system’s service curve are very close to the ones obtained by simulations and that the computational complexity to obtain them is significantly reduced compared to the model based on Markov Chains due to the absence of matrix computation. / Este trabalho apresenta um modelo baseado em Cadeias de Markov e aprimorado com o uso do método de Kernel de estimação não-paramétrica e de MMFM (Markov Modulated Fluid Model) com o objetivo de avaliar e descrever o desempenho do enlace de transmissão em sistemas OFDM-TDMA. Para tal, modelos de tráfego baseados no Método de Kernel e em MMFM com ajuste da função de autocorrelação são propostos. A partir do modelo implementado para o sistema OFDM-TDMA, foram obtidas equações para estimação de parâmetros de QoS como retardo e tamanho médio da fila no buffer. Os resultados obtidos confirmam que o modelo proposto é bastante eficiente ao descrever os indicadores de desempenho do sistema. O uso de MMFM para modelar o processo de chegada de pacotes aprimora os estimadores de parâmetros de QoS tornando as estimativas bem próximas dos valores obtidos com as simulações. Também deduziu-se uma equação para a curva de serviço de Sistemas OFDM-TDMA. Em seguida, utilizando-se desta curva de serviço e do conceito de Processo Envelope foi proposta uma equação para estimação de probabilidade de transbordo do buffer em sistemas OFDM-TDMA. Os resultados obtidos mostram que as estimativas de probabilidade de transbordo baseadas na curva de serviço do sistema se aproximam bem dos resultados da simulação e a complexidade computacional do cálculo necessário para obtê-los é significativamente reduzida em relação ao modelo definido utilizando Cadeias de Markov.