Virtual Private LAN Service (VPLS) networks have emerged as a popular solution for providing scalable and efficient Layer 2 connectivity across wide-area networks. However, designing secure and scalable VPLS networks presents significant challenges. The full-mesh tunneling approach in HIP-based VPLS networks results in the N square scalability problem. This thesis addresses the scalability issue in HIP-based Virtual Private LAN Service (VPLS) networks by introducing relay routers. An optimization model based on the Capacitated Facility Location Model is proposed to select the optimal relay routers for a given network topology. The objective of the model is to minimize the cost of setting up and maintaining relay routers while ensuring proper network operation. The proposed solution is evaluated using Software-Defined Networking (SDN) and Mininet-based simulations. The results show that the proposed approach is effective in reducing the scalability issue in HIP-based VPLS networks.

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / This work proposes a methodology for feasibility study of the distribution of natural gas to remote areas without access through a backbone pipeline. In recent years, one can observe a strong increase in the participation of natural gas as input in energy supply all around the world, including Brazil. The State of CearÃ, in the Northeastern Brazil, shows nowadays a natural gas supply superavit of about four million cubic meters per day. Present natural gas distribution in Cearà State occurs only in Fortaleza Metropolitan area. Although there are in the State many important urban development poles with significant potential to consume natural gas they cannot count yet with necessary supply equipments of that power input as gas pipeline. This is an important problem because wood fuel is largely used in the countryside notwithstanding its damage to the environment. All over the world the attendance of secondary markets with natural gas has been supported by trucks or trains lines as a first step before implementing a pipeline. This work aims to propose and apply a methodology to find the economic and logistics feasibility to distribute natural gas to remote regions. Such a methodology makes use of discrete choice demand forecasting technique using both revealed and stated preference data as well as the capacity facility location problem modelling and conventional indicators of economic feasibility. A case study is discussed involving the CRAJUBAR region of Cearà State. The work aims to contribute in identification of scenarios in which one can have feasible situations of energy input substitution. / Esta dissertaÃÃo propÃe uma metodologia para estudo de viabilidade da distribuiÃÃo secundÃria de gÃs natural em regiÃes afastadas de redes primÃrias de gasodutos. Diante da seguranÃa de fornecimento do gÃs natural apresentada atualmente no paÃs e no Mundo, a sua participaÃÃo na matriz energÃtica vem se intensificando nos Ãltimos anos. O Estado do Cearà apresenta superavit na oferta equivalente a quatro milhÃes de metros cÃbicos por dia de gÃs. Atualmente, a distribuiÃÃo do gÃs natural, nesse Estado, à realizada apenas na RegiÃo Metropolitana de Fortaleza, sendo que no interior se encontram importantes polos de desenvolvimento, como a RegiÃo do CRAJUBAR com uma base industrial com potencial de consumo de gÃs natural, que poderia levar à substituiÃÃo do uso principalmente de lenha no processo produtivo das empresas e, tambÃm, poderia propiciar a interiorizaÃÃo do uso do energÃtico em regiÃes ainda nÃo atendida por gasodutos. O atendimento aos consumidores de gÃs natural tem ocorrido por meio da utilizaÃÃo de distribuiÃÃo secundÃria (gasoduto virtual) indutora de mercado. Assim o objetivo deste estudo reside em propor e aplicar uma metodologia de determinaÃÃo da viabilidade da distribuiÃÃo secundÃria do gÃs natural para regiÃes nÃo atendidas por gasodutos, instrumentada pelo uso de tÃcnicas de previsÃo de demanda, de otimizaÃÃo de custos e de planilha eletrÃnica na determinaÃÃo da viabilidade econÃmica. O trabalho busca contribuir na identificaÃÃo de cenÃrios viÃveis de substituiÃÃo energÃtica para o uso do gÃs natural na regiÃo em estudo.

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