Multi-transport devices are becoming more common, but sophisticated software is needed to fully realize the advantages of these devices. In this paper, we examine the performance of dynamic transport switching, which selects the best available transport for communication between two devices. We simulate transport switching within the Quality of Transport (QoT) architecture and show that it can effectively mitigate the effects of congestion and interference for connections between two multi-transport devices. We then evaluate dynamic transport switching overhead to characterize its effect on application throughput. Based on these insights, we identify several limitations of the QoT architecture and present solutions to improve performance.

Este trabalho apresenta uma análise sobre a Arquitetutra PCE (Path Computation Element), como alternativa para o roteamento inter-domínios em redes heterogêneas, ou seja, em ambientes onde ocorre a integração do domínio óptico, das redes de transporte ópticas, com o domínio eletrônico, das redes convencionais, tratando inclusive com questões de qualidade de transmissão do sinal óptico, ou QoT (Quality of Transmission). Os objetivos e o funcionamento do mecanismo do PCE em redes integradas são detalhados. São apresentados também os conceitos e definições das redes ópticas, bem como seus principais elementos, a proposta de interconexão das mesmas com as redes convencionais provendo uma rede única e integrada, o papel dos planos de controle, e os principais mecanismos de roteamento. A análise do PCE foi direcionada para o comportamento do principal protocolo utilizado na sua arquitetura, denominado PCE Protocol. De forma mais específica, foi realizada a análise de suas mensagens de requisição de rotas e das mensagens de respostas a estas requisições, e sua interferência no tráfego dos enlaces das redes onde são introduzidas. A partir daí é apresentada uma proposta de extensão de parâmetros para o protocolo PCE Protocol, com o objetivo de atender necessidades específicas de QoT, baseado em estudos das particularidades das características das transmissões ópticas. A partir destas definições, foram realizadas análises adicionais a fim de verificar o impacto com relação ao tráfego gerado em enlaces de diferentes larguras de banda, com a definição original do protocolo, e com a extensão proposta, permitindo uma comparação entre ambos. / This thesis presents an analysis of Path Computation Element Architecture (PCE) as an alternative to be implemented in heterogeneous network inter-domain routing, in other words, environments where optical domains are integrated with the electronic domains of conventional networks. Also, the ability of PCE to manage issues regarding the transmission quality of the optical signal, the QoT (Quality of Transmission), is presented. Objectives and functionality of the PCE mechanism in integrated networks is detailed. Concepts and definitions regarding optical networks and their main elements, the aim of interconnection with conventional networks to build a unified and integrated network, the role of control planes, and the main routing mechanisms are also presented. The analysis of the PCE was focused on the behavior of its main protocol, called PCE Protocol. Specifically, the analysis was performed on both its request and response messages, in addition, the interference in the traffic of the links where these messages had been introduced was also analyzed. Afterwards, an extension of the PCE Protocol parameters was proposed based on the study of optical transmission characteristics, with the aim of meeting specific QoT requirements. From these definitions, further analyses of the impact on the traffic in links with different bandwidths were performed, using the PCE protocol, with and without the proposed extension, allowing a comparison between them.

Este trabalho apresenta uma análise sobre a Arquitetutra PCE (Path Computation Element), como alternativa para o roteamento inter-domínios em redes heterogêneas, ou seja, em ambientes onde ocorre a integração do domínio óptico, das redes de transporte ópticas, com o domínio eletrônico, das redes convencionais, tratando inclusive com questões de qualidade de transmissão do sinal óptico, ou QoT (Quality of Transmission). Os objetivos e o funcionamento do mecanismo do PCE em redes integradas são detalhados. São apresentados também os conceitos e definições das redes ópticas, bem como seus principais elementos, a proposta de interconexão das mesmas com as redes convencionais provendo uma rede única e integrada, o papel dos planos de controle, e os principais mecanismos de roteamento. A análise do PCE foi direcionada para o comportamento do principal protocolo utilizado na sua arquitetura, denominado PCE Protocol. De forma mais específica, foi realizada a análise de suas mensagens de requisição de rotas e das mensagens de respostas a estas requisições, e sua interferência no tráfego dos enlaces das redes onde são introduzidas. A partir daí é apresentada uma proposta de extensão de parâmetros para o protocolo PCE Protocol, com o objetivo de atender necessidades específicas de QoT, baseado em estudos das particularidades das características das transmissões ópticas. A partir destas definições, foram realizadas análises adicionais a fim de verificar o impacto com relação ao tráfego gerado em enlaces de diferentes larguras de banda, com a definição original do protocolo, e com a extensão proposta, permitindo uma comparação entre ambos. / This thesis presents an analysis of Path Computation Element Architecture (PCE) as an alternative to be implemented in heterogeneous network inter-domain routing, in other words, environments where optical domains are integrated with the electronic domains of conventional networks. Also, the ability of PCE to manage issues regarding the transmission quality of the optical signal, the QoT (Quality of Transmission), is presented. Objectives and functionality of the PCE mechanism in integrated networks is detailed. Concepts and definitions regarding optical networks and their main elements, the aim of interconnection with conventional networks to build a unified and integrated network, the role of control planes, and the main routing mechanisms are also presented. The analysis of the PCE was focused on the behavior of its main protocol, called PCE Protocol. Specifically, the analysis was performed on both its request and response messages, in addition, the interference in the traffic of the links where these messages had been introduced was also analyzed. Afterwards, an extension of the PCE Protocol parameters was proposed based on the study of optical transmission characteristics, with the aim of meeting specific QoT requirements. From these definitions, further analyses of the impact on the traffic in links with different bandwidths were performed, using the PCE protocol, with and without the proposed extension, allowing a comparison between them.

Computing devices are commonly equipped with multiple transport technologies such as IrDA, Bluetooth and WiFi. Transport switching technologies, such as Quality of Transport (QoT), take advantage of this heterogeneity to keep network sessions active as users move in and out of range of various transports or as the networking environment changes. During an active session, the goal is to keep the device connected over the best transport currently available. To accomplish that, this thesis introduces a two-phase decision making protocol. In phase one, intra-device prioritization, users indicate the relative importance of criteria such as speed, power, service charge, or signal range through a comprehensive user interface. QoT-enabled devices process this information with the prioritized soft constraint satisfaction (PSCS) scoring function to ascertain the transport that best meets the user's needs. The second phase, inter-device negotiation, facilitates two QoT-enabled devices in agreeing to a unified selection of the best transport. This phase uses a modified version of the PSCS scoring function based on the preferences of both users. Additionally, devices may utilize multiple transports simultaneously to more accurately meet user demands. The PSCS scoring function considers pairs of transports and calculates the ratio that will yield the desired performance. Another set of functions, also presented in this thesis, is then used to accomplish the desired performance level despite the potential introduction of additional overhead.

Computing devices are commonly equipped with multiple transport technologies such as IrDA, Bluetooth and WiFi. Transport switching technologies, such as Quality of Transport (QoT), take advantage of this heterogeneity to keep network sessions active as users move in and out of range of various transports or as the networking environment changes. Autonomous transport switching technologies rely on information regarding current network status and the ambient wireless environment in order to make intelligent decisions. This thesis proposes Brand X, a cross-layer architecture designed for a QoT environment to provide timely and accurate environment information in order to facilitate autonomous transport switching. This thesis also presents a performance analysis of network protocol stack latency in a QoT environment considering the various cross-layer mechanisms utilized in Brand X and other architectures.