Technologies within embedded real-time systems are continuously evolving making such systems intelligent. This evolution has increased the interest in the data utilization while real-time constraints are considered. In this paper, we consider real-time constraints for programs communicating using a circular buffer communication paradigm. We propose a first result optimizing the buffer size. Our second contribution consists in providing an analytical characterization of the temporal validity and reachability properties of the data propagating along a functional chain. Last but not least, we propose a scheduling policy ensuring the consistency and the temporal validity of the used data.