Real-time Ethernet variants are expected to build the future communication infrastructure in cars. First camera based driver assistance functions will communicate using IEEE 802.1 AVBs credit-based shaping. But for the strict timing requirements of automotive control-traffic, AVBs current timing guarantees are insufficient. The upcoming IEEE 802.1Qbv standard proposes synchronous time-triggered traffic to overcome these limitations. This paper presents a low footprint microcontroller based communication architecture, that supports both traffic classes in parallel while using standard hardware components. It allows first realistic performance analyses of coexistent traffic shaping strategies in a software based implementation.