Analysis of the impact of communication protocols on service quality in ERTMS automatic train control systems.

The ERTMS-ATC system is a distributed system where the Driver Machine Interface (DMI) is a slave unit of the train onboard vital computer (EVC). In this paper we analyze two types of communication protocols for the EVC-DMI interactions, based, respectively, on cyclic and acyclic messages’ exchange. Adopting a modular modeling methodology, we assess their impact on significant dependability-related indicators. The analysis of the obtained results allows to quantify the improvements in adopting an acyclic protocol, possibly with one spare DMI component.