On the performability of on-board train networks with fault-tolerant controllers

This paper studies a mixed load of control and entertainment on top of Gigabit Ethernet on-board a train wagon. The control load is comprised of sensors and actuators of different sampling periods. There is a dedicated server for control and a dedicated server for entertainment. It is proven that the system can tolerate the failure of one controller, shifting both entertainment and control loads to the remaining controller while guaranteeing correct performance. The maximum acceptable entertainment load is found. Enhancements to the network are introduced in order to minimize degradation of entertainment service due to a controller failure. OPNET simulations are used to study packet transmission/reception and end-to-end delay. Finally, a performability model is developed; this model will help system designers determine the cost- effectiveness of architectural features aiming at increasing performance.