Lightweight hard real-time communication for commodity cluster systems

The switched Ethernet has been the network topology for distributed real-time systems and embedded control systems. However, Ethernet switches lack of build-in policing features thus nodes interconnected need to be cooperative for bandwidth control. In this paper, the design and implementation of lightweight hard real-time communication approach for commodity cluster systems in switched Ethernet environment are introduced. First, the end-to-end delay bounds are analyzed using network calculus theories. Then the dual-level traffic smoothing technique is introduced, integrated with real-time micro-kernel, lightweight clock synchronization protocol and zero-copy based real-time communication protocol, to realize lightweight hard real-time communication for commodity cluster system. Finally, to demonstrate the performance of our approach, performance measurements are made over Fast/Gigabit switched Ethernet. The results show that our approach can provide very satisfying lightweight hard real-time communication performance than other approaches.