Recent public cooperation between the Federal University of Technology – Parana (UTFPR) and the Toledo Municipality plans to implement the concept of smart cities in this city. In this context, one of the applications under development intends to track the recyclable garbage collector trucks in real time over the Internet. Actually, fleet vehicle tracking is one of the main applications for smart cities. LoRaWAN stands out among network technologies for smart cities due to operating in an open frequency range, covering long distances with low power consumption and low equipment cost. However, the coverage and performance of LoRaWAN is directly affected by both the environment and configuration parameters. In addition, tracking devices must be able to send its coordinates to the Internet even when the vehicle goes through zones where there are obstacles for electromagnetic waves such as elevated buildings or valleys. In this paper we perform experimental investigations to evaluate four LoRaWAN tracking devices, two available out of the box and two assembled and programmed. The behavior of each tracking device is analyzed when moving at a constant speed through three representative urban areas totaling 10.71 km2. The two most efficient tracking devices are analyzed in a stretch of 3.5 km with speeds ranging from 0 to 30 km/h, 0 to 50 km/h and 0 to 100 km/h. Results include a quantitative and qualitative aspects, including the received signal strength indication (RSSI), signal-to-noise ratio (SNR), packet delivery ratio (PDR), and spreading factor (SF) for the received geographic coordinates. As the devices depend on the quality of the signal offered by the network, we also present the results of the development and evaluation of the LoRaWAN network, by planning its coverage throughout the city.

Software-defined networks (SDN) usually rely on a centralized controller, which has limited availability and scalability by definition. Although a solution is to employ a distributed control plane, the main issue with this approach is how to maintain the consistency among multiple controllers. Consistency should be achieved with as low impact on network performance as possible and should be transparent for controllers, without requiring any change of the SDN protocols. In this work, we propose VNF-Consensus, a virtual network function that implements Paxos to ensure strong consistency among controllers of a distributed control plane. In our solution, controllers can perform their control plane activities without having to execute the expensive tasks required to keep consistency. Experimental results are presented showing the cost and benefits of the proposed solution, in particular in terms of low controller overhead. | INTRODUCTIONSoftware-defined networks (SDN) separate the control plane from the data plane, which improves their flexibility, programmability, and management. 1,2 The control plane is usually centralized, consisting of a single controller, while the data plane consists of numerous network devices distributed across the network. While a centralized approach is attractive as it is simpler to operate and manage, it represents a vulnerability as the controller is a single point of failure with a direct impact not only in terms of resilience (i.e., if the controller fails the whole network stops running) but also on performance and scalability 3 (i.e., the single controller has to process all requests from all switches). The solution is to distribute the control plane, employing multiple controllers that share responsibilities. 4 Several different distributed SDN control plane strategies have been proposed. 5,6 Although the advantages of employing multiple controllers should be clear, there is also a cost to pay: in order to employ a distributed control plane it is necessary to employ techniques to guarantee the consistency among the

Redes LPWAN (Low-Power Wide-Area Network) são um tipo de rede sem-fio projetada para cobrir uma extensa área a uma baixa taxa de transferência de bits. Entre as tecnologias LPWAN, o padrão aberto LoRaWAN destaca-se por operar em uma faixa de frequência aberta, atingir um longo alcance, pouco consumo de energia e baixo custo dos equipamentos. Este artigo descreve a implantação e avaliação de uma rede LoRaWAN para apoiar a construção do conceito de cidades inteligentes no município de Toledo/PR. A avaliação considera a qualidade do sinal em diversos pontos do município e confronta os dados obtidos com um modelo de simulação. Também são apresentados o plano para expansão da rede e algumas aplicações em desenvolvimento.

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The use of open standards and integrative nature are features that made Web Services an interesting area to academic research and to industry. This chapter introduces the concepts behind the Service Oriented Architecture, Web Services, in particular. This text shows, through a use case, the benefits of this architecture and its security challenges. Afterwards, we present some research projects and technologies that deal with these security challenges. ResumoDevido a sua característica integradora e por fazer uso de padrões abertos, os Serviços Web se tornaram uma área de grande interesse para pesquisa e para a indústria. Neste capítulo, pretende-se introduzir ao leitor os conceitos da arquitetura orientada a serviços, e em particular, a sua mais atual caracterização, os Serviços Web. Será mostrado, através de um cenário de uso, os benefícios em utilizar tal tecnologia e também serão apresentados os desafios de segurança associados a esta. Por fim, são apresentados alguns trabalhos de pesquisa e tecnologias voltadas para tratar tais desafios de segurança.

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A rede de comunicação sem-fio e longa distância LoRaWAN vem sendo amplamente adotada para fornecer conectividade a objetos localizados tanto em centros urbanos quanto em localidades mais remotas. No entanto, o padrão LoRaWAN não apresenta uma estratégia para reenviar pacotes perdidos, apesar de apresentar marcações para solicitar a confirmação de um pacote recebido. Este trabalho propõe um algoritmo chamado CR-LoRaWAN para gerenciar a retransmissão de pacotes em redes LoRaWAN. Considerando um cenário de rastreamento de objetos em movimento, o algoritmo proposto foi avaliado em modelos de simulação bem como na implementação em um dispositivo de rastreamento. Os resultados apresentam a eficiência do algoritmo proposto ao compará-lo a uma estratégia onde não há confirmação.