CAN was, is, and will be the most important in-vehicle network for all kind of transportation systems. More than 4,5 billion of CAN chips have been installed worldwide. All modern cars are equipped with CAN networks. CAN is also used in many other embedded control systems. In high-volume applications, system designers often use proprietary higher-layer protocols. In some lower-volume applications, the requirements are quite specific. This leads to application-specific higher-layer protocols such as Arinc 826.