Abstract
In the Internet of Things (IoT), data is handled and stored by software known as middleware (located on a server). IoT devices send such data through an application layer protocol that may be different from those supported by the middleware. This paper proposes an application layer gateway, called MiddleBridge, that translates Constrained Application Layer Protocol (CoAP), Message Queuing, Queuing Telemetry Transport Protocol (MQTT), Data Distribution Service (DDS), and Websockets messages into HTTP. MiddleBridge can be deployed on any computer with Java virtual machine because all servers are embedded in its code, enabling IoT gadgets to transmit data to any REST endpoint seamlessly. With the proposed approach, devices can send a smaller message to an intermediary (MiddleBridge), which restructures it and forwards to a middleware, reducing the time that a device spends transmitting. The created graphical user interface allows users to configure messages conversion and forwarding in runtime. The efficiency of such approach is evaluated through the packet size and response times considering the data sent to Orion context broker (a Fiware project). Results show that packet size that is sent by an IoT device through MiddleBridge is 17 times smaller than sending a straight HTTP request to the server and significantly reduces the transmission time.
•MiddleBridge converts MQTT, CoAP, Websockets, and DDS messages into HTTP.•The solution reduces the amount of time that a device spends transmitting.•MiddleBridge receives a smaller message, restructures it and forwards to a middleware.•Packet size produced by an IoT device was 17 times smaller than a direct HTTP request.