Increasingly, Ethernet is being used in automotive as a vehicle network backbone. It is ideal for service-oriented communications; streamed communications, such as Audio/Video Bridging (AVB) ; and Diagnostics over Internet Protocol (DoIP)  communications - areas in which high-bandwidth and reliable performance are essential.Designers are accustomed to network communication systems CAN, LIN, and FlexRay, but how will the timing performance be verified in an Ethernet network? This paper looks at network-wide timing analysis challenges where a mixture of CAN, FlexRay, and Ethernetbased busses co-exist.It is also worth noting that the AUTOSAR standard  supports timing definition for all elements in a mixed topology network, but again, accounting for the many different timing paths is a non-trivial process.Figure 1The Ethernet backbone serving different domains.Due to features are distributed in the vehicle, the communication need is typically tightly related to the feature complexity. Also different features have also requirements of isolation from other features, for example infotainment communication may need to be isolated from dynamic chassis control.One efficient way to design the topology in the vehicle is to have a backbone with different domain sub-networks (Figure 1). This allows the designer to isolate different domains and keep control over the communication.