Scheduling of rate-constrained and time-triggered traffic in multi-cluster TTEthernet systems

Multi-cluster systems with real-time networks are gaining increasing importance to address the communication needs of large-scale embedded systems in different domains such as automotive, factory automation and health-care systems. At the same time, heterogeneous application subsystems with varying criticality levels require different timing models including time-triggered communication, event-triggered communication with rate-constraints and best-effort communication. An example is the coexistence of periodic control functions, event-triggered comfort functions and streaming multimedia services of in-vehicle electronic systems. This paper presents a scheduling algorithm as well as a simulation and verification framework for such multi-cluster systems. We support the allocation and scheduling of time-triggered and rate-constrained services to processing elements and communication links of multiple Time-Triggered Ethernet (TTE) clusters. The simulation and verification framework supports the automatic generation of test cases based on generic scenario parameters including the connectivity degree as well as the number of clusters, processing elements, switches and services. Thereby, we enable a comprehensive evaluation of the scheduling algorithm for use cases of varying complexity. In addition, the simulation and verification framework is a foundation for the systematic comparison of different scheduling algorithms including the evaluation of schedulability and runtime for different types of scenarios.