부산대학교 도서관

Internet of Things (IoT) is a promising market and data gathered by IoT devices is highly valuable. The software that handles and stores these data is known as IoT middleware. The devices transfer data to middleware through an application protocol, which can be different from those supported by middleware. This paper proposes an application layer gateway that converts Message Queuing Telemetry Transport Protocol (MQTT) messages into HTTP. This solution can be deployed on a computer or Raspberry Pi, allowing devices to seamlessly send data to any REST endpoint. Instead of sending data directly to a middleware, IoT devices can send a smaller message to this bridge, which reconstructs it and forwards to a middleware, reducing the stress on the IoT device. The graphical user interface allows users to configure aspects related to messages conversion and forwarding in runtime. The paper demonstrates the efficiency of this approach by evaluating three scenarios where data is sent to Orion context broker (a Fiware project), which reveals that packet size that is sent by an IoT device through this proposed approach is 10 times smaller than other bridges and 17 times smaller than sending an HTTP request straight to the server.