The increasing number of driver assistance, infotainment and entertainment systems in automobiles results in higher requirements for bandwidth, fault tolerance and timing behaviour concerning the in-vehicle communication structure. In future, in-vehicle networks based on current technologies will reach their limits due to insufficient scalability and complexity. Real-time (RT) Ethernet is a new, scalable approach to reduce the complexity of these networks significantly. This paper demonstrates the architecture of a RT Ethernet prototype platform based on an ARM centred system-on-chip, which achieves timing and bandwidth characteristics of a typical future automotive application. It is based on an advanced interrupt driven architecture.