Internet of Things networks together with the data that flow between networked smart devices are growing at unprecedented rates. Often brokers, or intermediaries nodes, combined with the publish/subscribe communication model represent one of the most used strategies to enable Internet of Things applications. At scalability viewpoint, cloud computing and its main feature named resource elasticity appear as an alternative to solve the use of over-provisioned clusters, which normally present a fixed number of resources. However, we perceive that today the elasticity and Pub/ Sub duet presents several limitations, mainly related to application rewrite, single cloud elasticity limited to one level and false-positive resource reorganization actions. Aiming at bypassing the aforesaid problems, this article proposes Brokel, a multi-level elasticity model for Pub/Sub brokers. Users, things, and applications use Brokel as a centralized messaging service broker, but in the back-end the middleware provides better performance and cost (used resources 3 performance) on message delivery using virtual machine (VM) replication. Our scientific contribution regards the multi-level, orchestrator, and broker, and the addition of a geolocation domain name system service to define the most suitable entry point in the Pub/Sub architecture. Different execution scenarios and metrics were employed to evaluate a Brokel prototype using VMs that encapsulate the functionalities of Mosquitto and RabbitMQ brokers. The obtained results were encouraging in terms of application time, message throughput, and cost (application time 3 resource usage) when comparing elastic and non-elastic executions.

Hoje em dia, existem centenas de projetos em curso em todo o mundo para redesenhar ambos os protocolos de comunicação e arquitetura da Internet. Iniciativas são coletivamente chamadas de pesquisa sobre a " Internet do futuro ". A maioria dessas iniciativas dependem de sistemas distribuídos existentes, que, muitas vezes, limitam ou mesmo impedem o desenvolvimento de soluções totalmente inovadoras. A razão principal é que a grande maioria dos sistemas distribuídos são firmemente ligados com a pilha de protocolos TCP/IP. Neste artigo, será fornecido um debate de primeiro olhar sobre as relações entre as pesquisas sobre a Internet do futuro e sobre sistemas distribuídos, com foco em dependências e requisitos semelhantes entre essas áreas. A partir desta análise, torna-se evidente que muitos dos requisitos da Internet do futuro (e desafios abertos) são repetidos no panorama de sistemas distribuídos. Embora existam muitos estudos em ambas as frentes de pesquisa individualmente, o estudo dos principais desafios da Internet futuro, a tratar os requisitos de sistemas distribuídos é um tema ainda pouco explorado na nossa pesquisa contemporânea. Este trabalho tem como objetivo determinar as lacunas e requisitos que a Internet do futuro deve cumprir a fim de apoiar os sistemas distribuídos do futuro. Para apoiar este objetivo, um conjunto de métricas de projeto são identificados e um espaço de design convergente é proposto. Palavras-chave:Redes de Computadores. Sistemas Distribuídos. Arquitetura da Internet do Futuro. NovaGenesis.Abstract: Nowadays, there are hundreds of underway worldwide projects to redesign both communication protocols and architecture of the Internet. These initiatives are collectively called "future Internet" research. Most of these initiatives rely on existing distributed systems, which often limit or even prevent the development of "clean slate" solutions. The main reason is that the great majority of distributed systems are tightly-linked with the TCP/IP protocol stack. In this article, we provide a first glance discussion on the relationships between future Internet and distributed systems research, focusing on dependencies and similar requirements among these areas. From this analysis, it becomes evident that many of the future Internet requirements (and open challenges) are repeated in the distributed systems landscape. Although there are many studies on both research fronts individually, the study of the key challenges of future Internet when addressing distributed systems requirements is a topic yet not explored in our contemporary research. This paper aims at determining the gaps and requirements future Internet must fulfill in order to support future distributed systems. To support this objective, a set of design metrics are identified and a convergent design space is proposed.

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