Modeling network traffic on a global network-centric system with artificial neural networks

This dissertation proposes a new methodology for modeling and predicting network traffic. It features an adaptive architecture based on artificial neural networks and is especially suited for large-scale, global, network-centric systems. Accurate characterization and prediction of network traffic is essential for network resource sizing and real-time network traffic management. As networks continue to increase in size and complexity, the task has become increasingly difficult and current methodology is not sufficiently adaptable or scaleable. Current methods model network traffic with express mathematical equations which are not easily maintained or adjusted. The accuracy of these models is based on detailed characterization of the traffic stream which is measured at points along the network where the data is often subject to constant variation and rapid evolution. The main contribution of this dissertation is development of a methodology that allows utilization of artificial neural networks with increased capability for adaptation and scalability. Application on an operating global, broadband network, the Connexion by Boeingʼ network, was evaluated to establish feasibility. A simulation model was constructed and testing was conducted with operational scenarios to demonstrate applicability on the case study network and to evaluate improvements in accuracy over existing methods --Abstract, page iii

Evaluating the impact of traffic sampling in network analysis

Dissertação de mestrado integrado em Engenharia InformáticaThe sampling of network traffic is a very effective method in order to comprehend the behaviour and flow of a network, essential to build network management tools to control Service Level Agreements (SLAs), Quality of Service (QoS), traffic engineering, and the planning of both the capacity and the safety of the network. With the exponential rise of the amount traffic caused by the number of devices connected to the Internet growing, it gets increasingly harder and more expensive to understand the behaviour of a network through the analysis of the total volume of traffic. The use of sampling techniques, or selective analysis, which consists in the election of small number of packets in order to estimate the expected behaviour of a network, then becomes essential. Even though these techniques drastically reduce the amount of data to be analyzed, the fact that the sampling analysis tasks have to be performed in the network equipment can cause a significant impact in the performance of these equipment devices, and a reduction in the accuracy of the estimation of network state. In this dissertation project, an evaluation of the impact of selective analysis of network traffic will be explored, at a level of performance in estimating network state, and statistical properties such as self-similarity and Long-Range Dependence (LRD) that exist in original network traffic, allowing a better understanding of the behaviour of sampled network traffic.A análise seletiva do tráfego de rede é um método muito eficaz para a compreensão do comportamento e fluxo de uma rede, sendo essencial para apoiar ferramentas de gestão de tarefas tais como o cumprimento de contratos de serviço (Service Level Agreements - SLAs), o controlo da Qualidade de Serviço (QoS), a engenharia de tráfego, o planeamento de capacidade e a segurança das redes. Neste sentido, e face ao exponencial aumento da quantidade de tráfego presente causado pelo número de dispositivos com ligação à rede ser cada vez maior, torna-se cada vez mais complicado e dispendioso o entendimento do comportamento de uma rede através da análise do volume total de tráfego. A utilização de técnicas de amostragem, ou análise seletiva, que consiste na eleição de um pequeno conjunto de pacotes de forma a tentar estimar, ou calcular, o comportamento expectável de uma rede, torna-se assim essencial. Apesar de estas técnicas reduzirem bastante o volume de dados a ser analisado, o facto de as tarefas de análise seletiva terem de ser efetuadas nos equipamentos de rede pode criar um impacto significativo no desempenho dos mesmos e uma redução de acurácia na estimação do estado da rede. Nesta dissertação de mestrado será então feita uma avaliação do impacto da análise seletiva do tráfego de rede, a nível do desempenho na estimativa do estado da rede e a nível das propriedades estatísticas tais como a Long-Range Dependence (LRD) existente no tráfego original, permitindo assim entender melhor o comportamento do tráfego de rede seletivo