The complexity of in-vehicle networks puts the traditional design processes to a test. Last minute changes, difficult verification, testing, and similar issues add to the challenges. However, changing the design paradigm to a structured engineering process can lead to better, cheaper, and easier network designs. With the right tools to support such a process, the network design itself becomes as predictable as the communication on the bus, which is getting even more important with the advent of AUTOSAR. In this paper, such a concept and its benefits for real designs are explained.