Hard real-time scheduling protocol in Ethernet networks

For a long time, Ethernet has been supposed to be not suitable for Hard Real-Time communications as industrial process controls. The Ethernet Multiple Access Control (CSMA/CD) nature makes impossible to guarantee a deterministic medium access time. Hence, message delivery deadlines can't be guaranteed. In this paper, we make a novel approach to establish predictable message transfer under Ethernet networks. We propose a new Ethernet Access protocol called : EDF-CSMA which is inspired from the optimal scheduling centralized algorithm EDF (Earliest Deadline First). This protocol compatible with CSMA, gives guarantee prediction to Real-Time messages and performs better guarantee results than protocols in previous works. In deed, we prove the efficiency of our protocol by simulations and comparisons to others Hard Real-Time communication protocols for Ethernet such as: CSMA-DCR, DOD-CSMA/CD, VTCSMA and RTCC.