Context: Nowadays one of the most beneficial business in IT area is web services with huge amount of users. The key ofsuccess in these type of services is flexibility in terms of providing same quality of services (QoS) and ability of fasttroubleshooting when number of users increase rapidly. To achieve these targets, evaluation of the user satisfaction is highlyessential. Moreover it is required to link user dissatisfaction to QoS parameters in terms of troubleshooting. Objectives: The main aim the research is to find an intelligent method for evaluation of the user satisfaction. The method isproposed to estimate quality-of-experience (QoE) without asking users to send their feed back. Connecting to this aim, thesecond target is finding the definition of function in equations of QoS=function(QoE). And finally, comparison of theimpact of QoS parameters on mobile application users and web site users is the last objective. Methods: For this research a web-server for video sharing propose is designed. The users can use it via web site or anAndroid mobile application. The three main QoS parameters (Packet-loss, delay and throughput) are changed gradually. Theusers are asked to score the mobile application and web site at the same time. In parallel the traffic of web-server is capturedand analyzed. Then based on variations in mean opinion scores (MOS) and also changes in TCP flags, the proper patternsfor each of the QoS parameters is provided. In this part the QoE is linked to transport layer. For the second objective, theQoE is directly linked to QoS. On the other words the graphs with QoE as horizontal axis and one of the QoS parameters asvertical axis are provided. And finally based on the gradient of these trends, the amount of impact of QoS parameters onmobile application users and web site users is compared. Results: Based on the results of the research, decrement in SYN and FIN flags and increment in ACK is an alarm for downgoing user satisfaction. In this situation, the problem is belongs to packet-loss. Increasing in the percentage of SYN is alsoa signal for user dissatisfaction. In this case, the problem is result of delay. And finally if the web-server problem is aboutthroughput then, SYN, FIN and ACK has up going trends. In all of the cases the rest of TCP flags has not clear up going ordecreasing trend.The correlation between QoS and QoE is formulated. The trends of MOS relative to QoS parameters for mobile phone andlaptop are very similar in case of packet-loss. For throughput the mobile phone users are a little more sensitive. The mostsignificant difference between the MOS values for mobile application and web site is belongs to delay. The increment indelay has really big negative effect on mobile application users. Conclusion: The final method for user satisfaction evaluation is based on the way of variations in the TCP flags. Among allthe flags, SYN, FIN and ACK passed the criteria to make the patterns. Moreover the method indicate the problem isbelongs to which of the QoS parameters. The correlation between QoE and QoS is formulated. And finally according tothese formulas, two separate web-servers for mobile application and web site is recommended.

Today's home network usually involves connecting multiple PCs and peripheral devices, such as printers and scanners, together in a network. This provides the benefit of allowing the PCs in the network to share Internet access and other resources. However, it is expected in the future, the home area network (HAN) will grow and extend to other home devices such as home entertainment systems (including digital TV, hi-fi stereo, etc.), appliances, webcam, security alarm system, etc. Connecting other home devices to a HAN provides users with many benefits not available in today's home networks. For example, home devices capable of connecting to the future HAN are able to share the content downloaded from broadband access anywhere in the home. Users can also have remote access and control of their home devices. To extend the home area network to all these different home devices, however, means that the traffic between the ISP and future HAN will be very different from the traffic generated by today’s home network. In today's home network, which consists mainly of multiple PCs, a best-effort approach is able to satisfy the need, since most of the traffic generated by PCs is not real-time in nature. However, in future HANs, it is anticipated that traffic generated from home devices requiring real-time applications such as multimedia entertainment systems, teleconferencing, etc. will occupy a large proportion of the traffic between the ISP and future HANs. In addition, given the variety of home devices that could potentially be added to future HANs, the amount and variety of traffic between the ISP and a future HAN will certainly be very different from today's home network that is dominated by Internet/data traffic. To allow HAN users of these real-time applications and various types of home devices to continue enjoying seamless experiences in using their home devices without noticing significant delays or unnecessary interruptions, it is important for the ISP to be able to effectively manage the channel to the home so that it can provide sufficient bandwidth to ensure high QoS for home applications. The aim of this thesis is to understand the types of traffic that will be expected and to develop an analytical model that will represent the traffic behaviour between the ISP and future HANs to understand how to manage the channel to provide high QoS. In this thesis, we use the continuous-time PH/M/n/m preemptive priority queue to model the traffic behaviour between the ISP and a future HAN. Three classes of traffic are defined in this model: real-time, interactive, and unclassified. Each of these three traffic classes receives a unique priority level. From the model one can approximate the amount of bandwidth required to be allocated for each traffic class for each household so that the total bandwidth required is minimized while the QoS requirements (delay and blocking probability) of the traffic generated by the home devices are met. Thus this model could potentially be used as a network planning tool for ISPs to estimate how much bandwidth they need to provide per household for homes that use home area network. Alternatively, it could also be used to estimate what quality of service (e.g. what is the mean delay and blocking probability expected) given a certain amount of bandwidth per household.

Our study investigates the performance of the WUSB standards and compares it to the Wimedia Standard. To the best of our knowledge, no technical contributions exist in the open literature at present simulating WUSB and its performance. The study showed that WUSB can achieve better throughput when bursting is enabled at the maximum burst size and it provides more accurate timing control of device activity than using the standard facilities of the WiMedia MAC. Our study also addresses protocol extensions and improvement to the original WUSB standard to support better Quality of Service (QoS). First improvement enables a di erent reservation mechanism along with contention based access to support higher priority security and medical system monitoring applications. Second improvement enables the host device to use an adaptive packet loss technique to change the packet size dynamically during the data transmission to achieve packet loss less than 10%. Third improvement enables redundancy in the cluster by adding a backup host to prevent mobility failures and changes. This backup host is chosen by a prede ned cost weighting function.

Today's home network usually involves connecting multiple PCs and peripheral devices, such as printers and scanners, together in a network. This provides the benefit of allowing the PCs in the network to share Internet access and other resources. However, it is expected in the future, the home area network (HAN) will grow and extend to other home devices such as home entertainment systems (including digital TV, hi-fi stereo, etc.), appliances, webcam, security alarm system, etc. Connecting other home devices to a HAN provides users with many benefits not available in today's home networks. For example, home devices capable of connecting to the future HAN are able to share the content downloaded from broadband access anywhere in the home. Users can also have remote access and control of their home devices. To extend the home area network to all these different home devices, however, means that the traffic between the ISP and future HAN will be very different from the traffic generated by today’s home network. In today's home network, which consists mainly of multiple PCs, a best-effort approach is able to satisfy the need, since most of the traffic generated by PCs is not real-time in nature. However, in future HANs, it is anticipated that traffic generated from home devices requiring real-time applications such as multimedia entertainment systems, teleconferencing, etc. will occupy a large proportion of the traffic between the ISP and future HANs. In addition, given the variety of home devices that could potentially be added to future HANs, the amount and variety of traffic between the ISP and a future HAN will certainly be very different from today's home network that is dominated by Internet/data traffic. To allow HAN users of these real-time applications and various types of home devices to continue enjoying seamless experiences in using their home devices without noticing significant delays or unnecessary interruptions, it is important for the ISP to be able to effectively manage the channel to the home so that it can provide sufficient bandwidth to ensure high QoS for home applications. The aim of this thesis is to understand the types of traffic that will be expected and to develop an analytical model that will represent the traffic behaviour between the ISP and future HANs to understand how to manage the channel to provide high QoS. In this thesis, we use the continuous-time PH/M/n/m preemptive priority queue to model the traffic behaviour between the ISP and a future HAN. Three classes of traffic are defined in this model: real-time, interactive, and unclassified. Each of these three traffic classes receives a unique priority level. From the model one can approximate the amount of bandwidth required to be allocated for each traffic class for each household so that the total bandwidth required is minimized while the QoS requirements (delay and blocking probability) of the traffic generated by the home devices are met. Thus this model could potentially be used as a network planning tool for ISPs to estimate how much bandwidth they need to provide per household for homes that use home area network. Alternatively, it could also be used to estimate what quality of service (e.g. what is the mean delay and blocking probability expected) given a certain amount of bandwidth per household.

Our study investigates the performance of the WUSB standards and compares it to the Wimedia Standard. To the best of our knowledge, no technical contributions exist in the open literature at present simulating WUSB and its performance. The study showed that WUSB can achieve better throughput when bursting is enabled at the maximum burst size and it provides more accurate timing control of device activity than using the standard facilities of the WiMedia MAC. Our study also addresses protocol extensions and improvement to the original WUSB standard to support better Quality of Service (QoS). First improvement enables a di erent reservation mechanism along with contention based access to support higher priority security and medical system monitoring applications. Second improvement enables the host device to use an adaptive packet loss technique to change the packet size dynamically during the data transmission to achieve packet loss less than 10%. Third improvement enables redundancy in the cluster by adding a backup host to prevent mobility failures and changes. This backup host is chosen by a prede ned cost weighting function.

No description available.

No description available.

Proportional Differentiated Services can be provisioned in terms of bandwidth, delay, or packet loss. Several studies contributed schedulers and packet droppers that achieved proportional bandwidth, delay, or loss differentiation. However, all these schemes differentiated in terms of only one of the three metrics. A simple, unified, scalable, and robust scheme to simultaneously control all three metrics was felt important. By controlling just delay and packet loss, proportional differentiation can be achieved in terms of all three metrics. A robust adaptive scheduler for proportional delay differentiation services is presented. Proportional services are further policed by a class based packet dropper. The combination of the adaptive scheduler and the packet dropper treats different traffic classes proportionally in terms of all three metrics. Simulation experiments show that regardless of the network traffic characteristics, our scheme can effectively differentiate services in terms of bandwidth, delay, and loss simultaneously.

Este trabalho apresenta uma avaliação do algoritmo EBS, uma política de escalonamento proposta para sistemas de tempo real flexíveis com qualidade de serviço baseado em limites superiores para tempos médios de resposta. Experimentos têm demonstrado propriedades vantajosas da política EBS em servidores Web com diferenciação de serviço. O objetivo do presente estudo é compreender o comportamento da EBS em relação à diferentes parâmetros que descrevem a carga de trabalho. Esse conhecimento é útil para obtenção de um melhor aproveitamento computacional. São apresentados experimentos e resultados que analisam a influência de cada um dos fatores considerados na qualidade do serviço oferecido. A partir desses resultados são tecidas conclusões acerca de abordagens para o dimensionamento de carga e de capacidade do servidor / This Master degree project has presented an evaluation of the EBS algorithm, a scheduling policy proposed for soft real-time systems with quality of service based on upper limits for average response times. Experiments have shown advantageous properties of the EBS policy on Web servers with service differentiation. The aim of this study is to understand the behavior of the EBS in relation to different parameters that describe the workload. This knowledge is useful for obtaining a better use of computing. Experiments and results are presented analyzing the influence of each factor considering the quality of service offered. From these results, conclusions are woven about approaches to the design load and server capacity

Este trabalho apresenta um estudo, implementação e validação em ambiente simulado de uma política de escalonamento de tempo real para provisão de QoS absoluto em serviço Web. Sintetizando características de escalonamento de tempo real, com baixa latência e de modelo re-alimentado, a política proposta permite um ajuste ponderado pela quantificação da exigência à qual o sistema está submetido por meio de suas classes. A meta é oferecer ações imediatas às requisições mais urgentes, sem, entretanto, degradar a qualidade do sistema como um todo. Verificou-se que a estratégia de escalonamento baseada em exigência (EBS - Exigency-Based Scheduling) é benéfica para o controle da qualidade de serviço oferecida. Escalonar de forma a evitar demasiado peso imposto ao sistema permite que o servidor tenha mais condições de cumprir os requisitos contratuais. Também foi alvo do estudo a criação de uma métrica de avaliação da satisfação de atendimento por parte dos usuários dos serviços. Os resultados alcançados com o emprego da política EBS sinalizam uma melhoria em termos de qualidade de serviço e melhor satisfação dos clientes de forma balanceada / The present work presents a study, implementation and validation in a simulated environment of a real time scheduling policy to provide absolute QoS for web services. Synthesizing characteristic from real time scheduling, low latency and feedback scheduling, the proposed policy allows an adjustment weighed by the quantification of the exigency which the system is exposed through its classes. The goal is to offer immediate actions to most urgent requests, without decreasing the system quality as a whole. It was verified that the scheduling strategy based on exigency (EBS - Exigency-Based Scheduling) helps to control the quality of service offered. Scheduling in order to avoid imposing a heavy load to the system gives more condition to the server to fulfill the requirements agreed. Another goal of this work is the creation of a metrics to evaluate the client satisfaction. The results achieved with the EBS policy indicate a higher quality of service and better client satisfaction