Analysis of CoAP Implementations for Industrial Internet of Things: A Survey

:Over the last few years, the Internet of Things (IoT) has grown in protocols, implementations and use cases. In terms of communication protocols, the Constrained Application Protocol (CoAP) stands out among the rest. This is extremely lightweight and capable of running in resource constrained devices and networks. There exist many implementations of CoAP, each of these with its own particular features and requirements. Therefore, it is important to choose the CoAP implementation that suits better to the specific requirements of each application. This paper presents a feature and empirical comparison of several open source CoAP implementations. First of all, it surveys current CoAP implementations, and compares them in terms of built-in core, extensions, target platform, programming language and interoperability. Then, it analyzes their performance in terms of latency, memory and CPU consumption in a real testbed deployed in an industrial scenario.