The transition from a distributed architecture to a domain controller architecture is relatively easy, and this upgrade is often just a matter of consolidating some of the functions that are scattered across different controllers into one controller.
These are often shifted within functional domains, with modest updates to adapt them to new models. The next stage is to reorganize the domain controller into a more general computing unit, concentrating most of the functions in the general computing unit, while the controllers in the secondary or tertiary network act only as actuators. The zone controller integrates the rest of the functions based on the physical layout of the vehicle.