Lightweight data streaming from IoT devices

The CoAP observe feature is a promising way to reduce energy consumption of IoT nodes and improve communication performance. To make the most benefit of this, the proxy which observes data from multiple nodes in a single IoT domain, must estimate the data lifetime and eliminate, or at least diminish, the impact of variability introduced by random transmission times from IoT nodes to proxy. We have investigated impact of lenient versus more conservative estimations of data freshness on traffic performance in the cluster and on energy consumption at IoT nodes. Results show that for exponentially distributed inter-observation times with mean of 60s, conservative estimations of Max_Age run smoothly on clusters with well over 500 nodes.