MDPI Appl. Sci. 2021, 11(11), 4879; Highly Cited Paper Award,
May 2021 · doi: 10.3390/app11114879
oT data exchange is supported today by different communication protocols and different protocolar frameworks, each of which with its own advantages and disadvantages, and often co-existing in a way that is mandated by vendor policies. Although different protocols are relevant in different domains, there is not a protocol that provides better performance (jitter, latency, energy consumption) across different scenarios. The focus of this work is two-fold. First, to provide a comparison of the different available solutions in terms of protocolar features such as type of transport, type of communication pattern support, security aspects, including Named-data networking as relevant example of an Information-centric networking architecture. Secondly, the work focuses on evaluating three of the most popular protocols used both in Consumer as well as in Industrial IoT environments: MQTT, CoAP, and OPC UA. The experimentation has been carried out first on a local testbed for MQTT, COAP and OPC UA. Then, larger experiments have been carried out for MQTT and CoAP, based on the large-scale FIT-IoT testbed. Results show that CoAP is the protocol that achieves across all scenarios lowest time-to-completion, while OPC UA, albeit exhibiting less variability, resulted in higher time-to-completion in comparison to CoAP or MQTT.