Embedded systems have developed from single microcontrollers to networked sys-tems and are moving further on to large open systems. As an example, automotive electronics started as a single microcontroller for engine control to develop into a local network of 50 and more electronic control units connected via several network standards and gateways which are found in current cars. These networks will be ex-tended by open wireless car-to-car or car-to-infrastructure communication enabling completely new functionality, such as advanced driver assistance systems that report approaching cars that could cause an accident. Other examples are found in health-care, where patients are monitored at home connected to a hospital data base and monitoring system rather than staying in the hospital for that purpose, or in smart buildings where different control functions are integrated to minimize energy con-sumption and adapt consumption to the available energy, or in energy supply net-works that are optimized to include renewable energy production. In all these cases we observe a transition from local closed networks with a single systems integrator controlling all design aspects (such as an automotive manufacturer) to larger open networks with many independent functions and different integrators following differ-ent design objectives. The Internet plays an important role supporting that trend. Unlike closed networks with a defined topology, such systems change over the life-time of a system.