Evaluating Publish/Subscribe Protocols for use in Constrained Networks

Considering the case of disaster relief and search and rescue operations, we can anticipate personnel operating with a total or partial lack of any pre-existing infrastructure. This means that ad hoc com- munication solutions must be established. Coupled with the abundant sensing capabilities provided through the innovation behind the Internet of Things (IoT), we need to identify suitable publish/subscribe protocols that can convey such data when facing various constrained networking conditions. In this paper, we evaluate MQTT, MQTT for Sensor Networks (MQTT- SN), and ZeroMQ in several different relevant networking conditions. Based on the analysis of each protocol, we have concluded that they are suitable for use in less constrained networks but struggle with efficient communication in the more challenging ones. We found that MQTT shows good performance in the less limiting networks we have tested, only surpassed by MQTT-SN in some cases. However, due to tooling maturity and unsurpassed community support, we consider MQTT the "overall winner".