Virtual Gateway in TCMS Execution Environment based on an Integrated Architecture

In the railway domain, the development trend is evolving from federated to integrated architectures, which promise massive cost reduction through higher functional integration of Train Control and Monitoring Systems (TCMS). An integrated architecture means that components are integrated on a computing node, which formerly were allocated to separate computing nodes. Therefore, the execution environment needs to support communication between these components on a computing node. Based on an integrated architecture, a virtual switch supporting time-space isolation and dynamic configuration has been proposed in previous work to address the mixed criticality of TCMS applications and dynamic coupling of vehicles. However, controlled information import and export between different data flows is not addressed in the state of the art. In this paper, we propose a virtual gateway residing in the TCMS execution environment to resolve property mismatches between different data flows and prevent fault propagation between applications of different safety critical levels. We capture the properties of data flows in the gateway specification and realise the gateway services by leveraging a database in the gateway. The experimental results show the isolation and the controlled information transportation between data flows.