Addressing Quality of Service and specification of quality attributes has been gaining a growing importance in the software engineering area. The research presented in this study investigates different approaches to specification of Quality of Service. UML profile for Quality of Service is one of the standards of the Quality of Service specification and is described in the QoS specification context. The research aim of this thesis is the evaluation of the UML profile for Quality of Service against the following criteria: expressiveness, reusability, understandability, applicability and tool support, as well as further comparison of the profile with other Quality of Service specification languages. To perform that, several tasks and activities were conducted, such as a survey on different QoS specification languages, an examination of the UML profile for Quality of Service, the formulation of the evaluation criteria, and the appliance of the criteria in the evaluation and comparison processes. This study is performed from the perspective of readers and users of the profile that are not UML experts but have sufficient knowledge of UML in terms of software systems analysis and design. The context of the UML profile and Quality of Service aspects include basic concepts of the UML 2.0 and Quality of Service which will be described along the thesis. The main contribution of the thesis is the evaluation of the UML profile for Quality of Service against a set of criteria, followed by explanations on the contents of the profile and how Quality of Service is specified within it. The presented comparison of the UML profile and other Quality of Service specification languages could be the basis for a user to decide what language to use in a particular situation. This study can be comprehended as a starting point for further evaluation of the UML profile and its comparison with other quality specification languages.

The efficient allocation of power is a major concern in today’s wireless communications systems. Due to the high demand in data rate and the scarcity of wireless resources such as power, the multi-user communication systems like the multiple access channel (MAC) and broadcast channel (BC) have become highly competitive environments for the users as well as the system itself. Theory of microeconomics and game theory provide the good analytical manner for the selfish and social welfare conflict problems. Instead of maximizing the system sum rate, our proposed system deals with fulfilling the utility (rate) requirement of all the users with efficient power allocation. The users formulate the signal to interference-plus-noise ratio (SINR) based quality-of-service (QoS) requirements. We propose the framework to allocate the power to each user with universal pricing mechanisms. The prices act as the control signal and are assumed to be some virtual currency in the wireless system. They can influence the physical layer operating points to meet the desired utility requirements. Centralized and distributed power allocation frameworks are discussed separately in the thesis with different pricing schemes. In wireless systems we have users that are rational in the game theoretic sense of making decisions consistently in pursuit of their own individual objectives. Each user’s objective is to maximize the expected value of its own payoff measured on a certain utility scale. Selfishness or self-interest is an important implication of rationality. Therefore, the mobiles which share the same spectrum have incentives to misinterpret their private information in order to obtain more utility. They might behave selfishly and show also malicious behavior by creating increased interference for other mobiles. Therefore, it is important to supervise and influence the operation of the system by pricing and priority (weights) optimization. In the centralized resource allocation, we study the general MAC and BC (with linear and nonlinear receiver) with three types of agents: the regulator, the system optimizer and the mobile users. The regulator ensures the QoS requirements of all users by clever pricing and prevents cheating. The simple system optimizer solves a certain system utility maximization problem to allocate the power with the given prices and weights (priorities). The linear and nonlinear pricing mechanisms are analyzed, respectively. It is shown that linear pricing is a universal pricing only if successive interference cancellation (SIC) for uplink transmission or dirty paper coding (DPC) for downlink transmission is applied at the base station (BS). For MAC without SIC, nonlinear pricing which is logarithmic in power and linear in prices is a universal pricing scheme. The prices, the resulting cost terms, the optimal power allocation to achieve the QoS requirement of each user in the feasible rate region are derived in closed form solutions for MAC with and without SIC using linear and nonlinear pricing frameworks, respectively. The users are willing to maximize their achievable rate and minimize their cost on power by falsely reporting their channel state information (CSI). By predicting the best cheating strategy of the malicious users, the regulator is able to detect the misbehavior and punish the cheaters. The infinite repeated game (RG) is proposed as a counter mechanism with the trigger strategy using the trigger price. We show that by anticipating the total payoff of the proposed RG, the users have no incentive to cheat and therefore our framework is strategy-proof. In the distributed resource allocation, each user allocates its own power by optimizing the individual utility function. The noncooperative game among the users is formulated. The individual prices are introduced to the utility function of each user to shift the Nash equilibrium (NE) power allocation to the desired point. We show that by implicit control of the proposed prices, the best response (BR) power allocation of each user converges rapidly. The Shannon rate-based QoS requirement of each user is achieved with minimum power at the unique NE point. We analyse different behavior types of the users, especially the malicious behavior of misrepresenting the user utility function. The resulting NE power allocation and achievable rates of all users are derived when malicious behavior exists. The strategy-proof mechanism is designed using the punishment prices when the types of the malicious users are detected. The algorithm of the strategy-proof noncooperative game is proposed. We illustrate the convergence of the BR dynamic and the Price of Malice (PoM) by numerical simulations. The uplink transmission within the single cell of heterogeneous networks is exactly the same model as MAC. Therefore, the results of the pricing-based power allocation for MAC can be implemented into heterogeneous networks. Femtocells deployed in the Macrocell network provide better indoor coverage to the user equipments (UEs) with low power consumption and maintenance cost. The industrial vendors show great interest in the access mode, called the hybrid access, in which the macrocell UEs (MUEs) can be served by the nearby Femtocell Access Point (FAP). By adopting hybrid access in the femtocell, the system energy efficiency is improved due to the short distance between the FAP and MUEs while at the same time, the QoS requirements are better guaranteed. However, both the Macrocell base station (MBS) and the FAP are rational and selfish, who maximize their own utilities. The framework to successively apply the hybrid access in femtocell and fulfill the QoS requirement of each UE is important. We propose two novel compensation frameworks to motivate the hybrid access of femtocells. To save the energy consumption, the MBS is willing to motivate the FAP for hybrid access with compensation. The Stackelberg game is formulated where the MBS serves as the leader and the FAP serves as the follower. The MBS maximizes its utility by choosing the compensation prices. The FAP optimizes its utility by selecting the number of MUEs in hybrid access. By choosing the proper compensation price, the optimal number of MUEs served by the FAP to maximize the utility of the MBS coincides with that to maximize the utility of the FAP. Numerous simulation results are conducted, showing that the proposed compensation frameworks result in a win-win solution. In this thesis, based on game theory, mechanism design and pricing framework, efficient power allocation are proposed to guarantee the QoS requirements of all users in the wireless networks. The results are applicable in the multi-user systems such as heterogeneous networks. Both centralized and distributed allocation schemes are analyzed which are suitable for different communication scenarios. / Aufgrund der hohen Nachfrage nach Datenrate und wegen der Knappheit an Ressourcen in Funknetzen ist die effiziente Allokation von Leistung ein wichtiges Thema in den heutigen Mehrnutzer-Kommunikationssystemen. Die Spieltheorie bietet Methoden, um egoistische und soziale Konfliktsituationen zu analysieren. Das vorgeschlagene System befasst sich mit der Erfüllung der auf Signal-zu-Rausch-und-Interferenz-Verhältnis (SINR) basierenden Quality-of-Service (QoS)-Anforderungen aller Nutzer mittels effizienter Leistungsallokation, anstatt die Übertragungsrate zu maximieren. Es wird ein Framework entworfen, um die Leistungsallokation mittels universellen Pricing-Mechanismen umzusetzen. In der Dissertation werden zentralisierte und verteilte Leistungsallokationsalgorithmen unter Verwendung verschiedener Pricing-Ansätze diskutiert. Die Nutzer in Funksystemen handeln rational im spieltheoretischen Sinne, indem sie ihre eigenen Nutzenfunktionen maximieren. Die mobilen Endgeräte, die dasselbe Spektrum nutzen, haben den Anreiz durch bewusste Fehlinterpretation ihrer privaten Informationen das eigene Ergebnis zu verbessern. Daher ist es wichtig, die Funktionalität des Systems zu überwachen und durch Optimierung des Pricings und Priorisierungsgewichte zu beeinflussen. Für den zentralisierten Ressourcenallokationsansatz werden der allgemeine Mehrfachzugriffskanal (Multiple Access Channel, MAC) und der Broadcastkanal (BC) mit linearen bzw. nichtlinearen Empfängern untersucht. Die Preise, die resultierenden Kostenterme und die optimale Leistungsallokation, mit der die QoS-Anforderungen in der zulässigen Ratenregion erfüllt werden, werden in geschlossener Form hergeleitet. Lineare und nichtlineare Pricing-Ansätze werden separat diskutiert. Das unendlich oft wiederholte Spiel wird vorgeschlagen, um Spieler vom Betrügen durch Übermittlung falscher Kanalinformationen abzuhalten. Für die verteilten Ressourcenvergabe wird das nichtkooperative Spiel in Normalform verwendet und formuliert. Die Nutzer wählen ihre Sendeleistung zur Maximierung ihrer eigenen Nutzenfunktion. Individuelle Preise werden eingeführt und so angepasst, dass die QoS-Anforderungen mit der Leistungsallokation im eindeutigen Nash-Gleichgewicht erfüllt werden. Verschiedene Arten des Nutzerverhaltens werden bezüglich der Täuschung ihrer Nutzenfunktion analysiert, und ein Strategy-Proof-Mechanismus mit Strafen wird entwickelt. Die Ergebnisse für den MAC sind anwendbar auf heterogene Netzwerke, wobei zwei neuartige Ansätze zur Kompensation bereitgestellt werden, die den hybriden Zugang zu Femtozell-Netzwerken motivieren. Mithilfe des Stackelberg-Spiels wird gezeigt, dass die vorgeschlagenen Ansätze in einer Win-Win-Situation resultieren.

L'objet de nos travaux porte sur la proposition d'une architecture hybride IEEE 802.11e/AFDX (Avionics Full Duplex switched ethernet) et sur l'étude des techniques permettant l'interconnexion d'un réseau avionique filaire AFDX et d'un réseau sans fil IEEE802.11e pour des applications de maintenance au sol. Ces techniques devront être capables de satisfaire les exigences temporelles des flux AFDX, en particulier la latence de bout à bout et la gigue. Pour des raisons de déterminisme d'accès au médium, nous avons focalisé nos travaux sur l'adaption de la méthode d'accès HCCA (HCF Controlled Channel Access) pour supporter les exigences de QoS du réseau AFDX. L'utilisation de la technologie IEEE 802.11e et de sa méthode d'accès HCCA n'est pas sans contrainte. L'HCCA est plus orientées pour transporter des flux multimédias tels que la voix et la vidéo, ces derniers n'imposant pas les mêmes contraintes temporelles ni le même niveau d'intégrité des données que les flux AFDX. Pour répondre aux exigences des trafics AFDX (gigue et latence), il est primordial d'améliorer l'HCCA. Nous proposons ainsi une méthode d'accès basée sur l'HCCA appelé AFS-HCCA (AFDX Flows Scheduling with HCCA). Notre méthode implémente deux ordonnanceurs: (1) un ordonnanceur local distribué sur toutes les stations (QSTA) et (2) un ordonnanceur centralisé et contrôlé par le point d'accès (HC). L'ordonnanceur local nommé AWS (AFDX Wireless Scheduler) améliore considérablement celui de référence HCCA, car il sérialise les trames en fonction de leurs contraintes temporelles et intègre une méthode de retransmission contrôlée. AWS n'agit pas sur l'optimisation de la bande passante, d'où notre proposition de deux stratégies supplémentaires: Optimized Solution et Released Bandwidth Solution. Les résultats obtenus par l'ordonnancement AWS distribué et ses stratégies de gestion de la bande passante montrent de réelles nouvelles performances par rapport à la norme HCCA. Cependant, il est indispensable d'ordonnancer de façon centralisée l'ensemble de ces flux pour garantir un accès optimal au médium. Nous avons proposé deux méthodes d'ordonnancement hors-ligne : AFBA (Advanced Fixe BandWidth Allocation) et VBA (Variable Bandwidth Allocation). AFBA alloue des bandes passantes fixes calculées à priori pour satisfaire les exigences temporelles de tous les flux AFDX. VBA quant à lui est basé sur une allocation de bandes passantes variables calculée en fonction des arrivées des trames dans les files d'attente de chaque station. Les ordonnanceurs locaux et centraux avec leurs variantes ont été modélisés et simulés avec OPNET à partir de différents scénarios réels de flux AFDX. Les résultats montrent que l'HCCA de référence de la norme 802.11e n'est pas adapté aux fortes contraintes temporelles de l'AFDX. Nos contributions en termes de sérialisation des flux et d'optimisation de la bande passante réduisent les pertes de trames de 93%, même dans un pire cas avec un réseau chargé et un taux d'erreur binaire élevé. / The object of our works concerns at the suggestion of hybrid architecture IEEE 802.11e / AFDX (Avionics Full Duplex switched ethernet) and the study of techniques allowing the interconnection of a wired avionic network AFDX and a wireless network IEEE802.11e for applications of maintenance the ground

Les réseaux véhicules (VANET) permettent d’offrir des solutions efficaces et rentables pour diverses applications telles que celles liées à : la sécurité routière, la gestion du trafic routier et les applications multimédia en utilisant les communications sans fil multi-sauts entre les véhicules communicants. Cependant, la mise en place et le maintien de liens multi-sauts fiables dans les environnements VANET posent de réels défis principalement à cause des changements rapides de topologie et des déconnexions fréquentes des liens, ce qui conduit à l'échec et l'inefficacité des protocoles de routage ad hoc traditionnels. Cette thèse propose une nouvelle famille de protocoles de routage (nommés AQRV, AQRV-1 et AQRV-2) adaptés aux caractéristiques intrinsèques des réseaux VANET. Basés sur l’estimation de la qualité de service en temps réel des segments de route (à savoir la probabilité de connectivité, le taux de perte de paquets et le délai), ces trois protocoles de routage reposent sur la sélection dynamique aux intersections du meilleur prochain segment de route pour un routage de bout-en-bout affichant la meilleure QoS (Quality of Service). Cette propriété de sélection opportuniste confère aux protocoles AQRV une bonne adaptation aux scénarios urbains à grande échelle tout en répondant aux contraintes QoS d'un grand nombre d'applications. Afin d'explorer la meilleure route en termes de QoS, la question du routage est vue comme un problème d'optimisation pour lequel un algorithme basé sur l’approche de colonie de fourmis ACO (Ant Colony Optimization) est employé. Par ailleurs, afin de réduire le temps d’exploration des routes et diminuer la charge du trafic de signalisation sur le réseau, une méthode opportuniste est proposée pour explorer efficacement le réseau et rechercher les meilleurs chemins disponibles en termes de QoS locale et globale. En outre, en exploitant des informations sur le trafic, telles que la densité véhiculaire, la vitesse des véhicules et de la longueur des segments de routes, des modèles théoriques sont élaborés pour estimer la qualité de service en temps réel pour deux scénarios distincts : des segments de routes à 1 et à 2 voies. Ces modèles offrent deux principaux avantages: des estimations précises de la qualité des segments de routes et un gain en charge de trafic de signalisation par rapport à la méthode d'estimation traditionnelle reposant sur l’envoi périodique de paquets de signalisation dédiés. Par ailleurs, le concept de TI (Terminal Intersection) est introduit pour mutualiser les routes entre intersections et éviter un routage basé sur nœuds communicants. Ainsi, les différentes paires de communication partagent les informations les plus à jour sur les meilleures routes, ce qui est bénéfique à la réduction de la charge de signalisation et au délai d’établissement des routes. Enfin, pour réduire davantage le trafic de signalisation et diminuer ainsi la congestion du réseau, la technique de transmission à un saut est améliorée, dans le protocole AQRV-2, grâce au concept d'élection distribuée du relayeur qui permet d’éviter la découverte du voisinage par échanges périodiques de paquets Hello. Les performances des protocoles proposés et la pertinence des modèles mathématiques de QoS dérivés ont été évaluées par des séries de simulations implémentant des scénarios réalistes. Une analyse approfondie a permis de montrer la meilleure performance des protocoles de routage développés en termes de signalisation, de délai et de taux de remise de paquets en comparaison aux protocoles de routage de référence. L’étude a également montré l’effet des différents paramètres protocolaires sur les performances globales. / Vehicular ad hoc networks (VANETs) are able to supply scalable and cost-effective solutions for various applications such as road safety, traffic efficiency and entertainments through multi-hop vehicle-to-vehicle wireless communications. However, developing multi-hop communications in VANET environments is a very challenging problem due to the rapid topology changes and frequent network disconnections, which lead to routing failure or inefficiency in traditional mobile ad hoc routing protocols. This dissertation proposes a novel class of routing protocols (AQRV, AQRV-1 and AQRV-2), which can account for specific characteristics of VANETs. Based on real-time QoS of road segment (namely connectivity probability, packet delivery ratio and delay), these three routing protocols rely on dynamic intersection-based best QoS route selection to cope with the scalability challenge in large-scale urban scenarios and meet varying requirements of a large number of applications. In order to explore the best QoS routing path, we regard the corresponding routing issue as an optimization problem, and propose an ACO-based (Ant Colony Optimization) algorithm to solve it. Besides, to reduce routing exploration time and decrease network overhead, an opportunistic method is proposed to explore the network and search available routing paths in terms of local/global QoS. In addition, by taking benefit from traffic information, such as vehicle density, vehicle speed and road length, we design mathematical models to estimate real-time QoS for 1-lane and 2-lane road scenarios. The main advantages of these models are twofold: provide accurate estimations of road segments’ QoS metrics and decrease the overhead compared with the estimation method by forwarding periodic packets. Furthermore, a TI-based (Terminal Intersection) concept is proposed to make a group of communication pairs share the same back-bone best route, which is beneficial to update latest routing information, decrease overhead and reduce transmission delay. Upon best route identification, data packets forwarding process is initiated including a dynamic road segment selection at intersections based on the updated global QoS, and a simple greedy carry-and-forward scheme to relay data packets between two neighboring intersections. Finally, to further reduce signaling overhead and alleviate network congestion, the one-hop geographical forwarding is improved using a distributed receiver-based election concept and utilized in AQRV-2 routing protocol to avoid periodic Hello packets exchanges. Extensive simulations are implemented to prove the effectiveness of the proposed protocols and the accuracy of the derived mathematical QoS models. A thorough analysis showed the better performance of our routing protocols in terms of overhead, delay and packet delivery ratio compared with reference routing protocols, and investigated the effects of related influencing factors.

Este projeto apresenta a proposta de uma arquitetura de Metaescalonador que leva em consideração o emprego de qualidade de serviço (QoS) para o ambiente de Computação em Nuvem. O Metaescalonador é capaz de realizar a alocação dos recursos dinamicamente, procurando atender as restrições temporais. Em resposta a esse dilema de escalonamento aplicado a Computação em Nuvem, este projeto propõe uma abordagem chamado MACC: Metascheduler Architecture to provide QoS in Cloud Computing. A função principal do MACC é distribuir e gerenciar o processamento das requisições de serviços entre os recursos disponíveis, cumprindo os termos agregados na SLA - Service Level Agreement. São apresentados resultados obtidos considerando-se diferentes algoritmos de roteamento e de alocação de máquinas virtuais. Os resultados apresentados são discutidos e analisados de acordo com as técnicas de planejamento de experimentos / This project proposes a Metascheduler architecture that takes into account the use of quality of service (QoS) to cloud computing environment. The Metascheduler is capable of dynamically allocating resources, trying to meet the timing constraints. In response to this scheduling dilemma applied to cloud computing, this project proposes an approach called MACC - Metascheduler Architecture to Provide QoS in Cloud Computing. The main function of the MACC is to distribute and to manage the service requests among the available resources, meeting the aggregate terms in the SLA - Service Level Agreement. Results are presented considering different routing algorithms and allocation of virtual machines. The results are discussed and analyzed in accordance with the techniques of experimental design

Em relação aos significativos resultados em Qualidade de Serviço (QoS) para servidores Web, existem ainda muitos problemas não resolvidos. Enquanto as abordagens atuais se limitam a prover QoS relativa através de diferenciação de serviço, este projeto apresenta e compara três modelos que tem por objetivo prover QoS absoluta para um array de servidores Web heterogêneos por meio de uma arquitetura de escalonamento ortogonal: A Multiple Queue (MQ), a Single Queue (SQ) e a Dynamic Single Queue (DSQ). A MQ consiste em receber a requisição HTTP e enviá-la para o servidor escolhido do array de servidores através do balanceamento de carga. A SQ e a DSQ possuem uma única fila gerenciada de forma centralizada. Enquanto a SQ envia a requisição somente quando o servidor esta livre, a DSQ seleciona o servidor com mais curto tempo de término mediante o uso de filas virtuais. Os modelos foram simulados considerando diferentes parâmetros e configurações para o ambiente. A avaliação de desempenho da arquitetura ortogonal demonstra que a mesma provê um bom desempenho na provisão de QoS absoluta com relação as mudanças instantâneas das cargas de trabalho no ambiente Web. Esta pesquisa estende os resultados da politica de escalonamento chamada EBS, concebida para provisão de garantias de tempo de resposta estocásticas em ambientes interativos online, especificamente para os servidores Web. Os resultados demonstram que a combinação da EBS na política de fila com a disciplina de recurso proposta neste trabalho é superior às outras combinações examinadas. Um modelo de política adaptativa é também introduzido / Despite the significant body of results in Quality of Service (QoS) for Web-Servers, many real-world problems are not easily supported. While the current approaches limit to provide relative QoS through service differentiation, this work presents and compares three models aiming at providing absolute QoS to Web Server on heterogeneous cluster by means of an Orthogonal Scheduling Architecture: The Multiple Queue (MQ), the Single Queue (SQ) and the Dynamic Single Queue (DSQ). The MQ consists in receiving the HTTP requests and delivering them for the selected processor in the server array to balance the load. SQ and DSQ have only one queue being managed by a central server. While SQ sends requests to the first free processors, the DSQ selects the processor with the minimun completion time with the aid of a virtual queue. The models were simulated considering different parameters and configurations for the environment. Performance evaluation of the Orthogonal Architecture demonstrates that it performs well in providing absolute QoS in face of instantaneous changes in the workloads. This work extends the results of a scheduling policy named EBS, tailored for providing stochastic response-time guarantees in online interactive systems, specifically for Web servers. Results show that the combination of EBS as the queue discipline with the resource discipline proposed in this work outperforms the other studied. An adaptive policy model is also introduced

Esta dissertação de mestrado tem como objetivo avaliar a integração de políticas de tolerância a falhas em uma arquitetura de Web Services com múltiplos módulos. A arquitetura utilizada é denominada WSARCH, e foi desenvolvida para o estudo das relações e interoperabilidade entre serviçcos. Os mecanismos de tolerência a falhas foram integrados aos módulos da arquitetura, testados, comparados e avaliados. A avaliação de desempenho mostrou que os mecanismos de tolerância a falhas introduzidos foram eficientes e apresentaram resultados adequados. As técnicas de reputação utilizadas na seleção de serviço atuaram satisfatoriamente e foram consideradas um importante avanço nos mecanismos da arquitetura / This master\'s thesis aims to evaluate the integration of fault tolerance mechanisms in a Web Services architecture with multiple modules. The architecture used is named WSARCH and was developed for the study of interactions and interoperability of services. WSARCH is an architecture conceived to receive tests and experiments involving concepts of Web Services. The fault tolerance tools were integrated in the architecture, tested, evaluated and comparated. The performance evaluation showed that the fault tolerance mechanisms introduced were ecient and presented appropriate results. The reputation techniques utilized in service selection operated successfully and were considered an important advance in the mechanisms of the architecture

Recentes pesquisas têm investigado modelos de garantia de desempenho baseados em restrições temporais, parametrizadas pela especificação de limites superiores de tempo médio de resposta. Este trabalho estende o desenvolvimento da política de escalonamento de temporeal EBS, aplicável a esse problema, apresentando um mecanismo de controle de admissão de requisições em aplicações com tais requisitos. A abordagem baseia-se em um método adaptativo capaz de administrar o nível de degradação do sistema, de forma a isolar o efeito do comportamento de um usuário sobre a qualidade de serviço oferecida aos demais usuários. Também é proposta uma modificação na implementação do algoritmo originalmente definido para a EBS, de forma a diminuir sua complexidade temporal. Resultados de simulação demonstram a efetividade dos mecanismos propostos / In recent research works performance guarantee models based on temporal constraints with specified response-time upper bounds have been investigated. This work extends the development of the EBS real-time scheduling policy, applicable to this problem, by proposing an admission control mechanism. The introduced approach is based on an adaptive model which, based on the system degradation level, tries to isolate the impact of the behavior of a given user upon the quality of service offered to the other users. Its also proposed a new algorithm to reduce the complexity order of the original EBS implementation. Simulation results illustrate the effectiveness of proposed methods

Diploma thesis deals with assign and distribution quality of service in mobile UMTS telecommunication networks. The project consists of two parts, theoretical and practical. Theoretical part of the project is focused to familiarize with functionality of the UMTS network with the main aspect at admission mechanism in radio part of the network as well as quality of service assign mechanisms according to service demands within core network of UMTS. Practical part of the project is given to simulation program OPNET Modeler and its capabilities in network design and testing various parameters of UMTS network with implementation quality of service mechanism. As the asset of diploma thesis becomes designed functional prototype of UMTS network with various options for individual settings user equipment as well as fixed mobile networks nodes.

The main task of this thesis was to explore the requirements of different telecommunications services on the network parameter, that are packet delay, packet loss, throughput, jitter. Make to test network service with WAN network emulator and load simulators. Next focus was to explore TCP congestion avoidance algorithms and focus on their throughput. The purpose of the first chapter is to introduce Quality of Service (QoS) for VoIP, video conversation, streaming audio, streaming video and data. The second chapter are to explore various types of delay, that are created from the sender through network device, transmission media to the recipient. The third chapter is to introduce NetDisturb application. It is application, that can emulate real properties of the data network and incoming traffic affect example packet delay, packet loss, bandwidth limit and so on. The key objectives of the fourth and fifth part is TCP protocol and TCP congestion avoidance algorithms. Hier are to introduce TCP protocol basic properties, congestion avoidance mechanisms and analysis of TCP congestion avoidance algorithms. In the practical part are created two laboratory exercises. First laboratory exercise is designed on the implementation QoS for various types of traffic. Second laboratory exercise is focused on the analysis TCP congestion avoidance algorithms and their throughput.