Um mecanismo de provisionamento de serviços com controle de demanda para a internet das coisas

Abstract

The Internet of Things (IoT) challenges network scalability, given the huge number of connected devices, and also creates a fertile scenario to explore redundant resources for service robustness increasing. Consequently, new IoT protocols have been proposed, being CoAP (Constrained Application Protocol) one of the most important for the application layer. In this work, we present a leading scalability analysis of CoAP in a network composed only by constrained devices to show the influence of network configuration parameters on the protocol performance. Moreover, we propose a service provisioning mechanism with demand control divided into two main components. The first component runs at the CoAP server and controls the demand and the selection of observers (clients that subscribe at the server to receive notifications about a resource). This component is based on the radio duty-cycle at the server and its energy consumption for operation mode switching while delivering services. The second component, on the other hand, runs at the client and conducts CoAP servers selection and switching. This component uses CoAP capabilities to switch servers, by following a sorted list of IP addresses obtained from a central infrastructure. This list is built according to the application requirements and is stored at the client. The mechanism is evaluated in a simulator designed for IoT (Cooja) and the results obtained show a significant reduction on energy consumption at the server compared with traditional CoAP. The mechanism also increases the reliability and the robustness of the IoT service provisioning and, furthermore allows energy consumption balance among the servers.