ABSTRACT
The classical fieldbus systems have been devised as highly specialized communication systems for the factory floor. This chapter shows the basic system architectures and the many design options. Evidently, the properties of the networks together with the applications have an important influence on these options and in fact limit the designer's flexibility with respect to the implementation. The chapter explains the distribution of the implementation efforts among the involved entities: field devices, clients on the Internet side, and a possible central access node. It also discusses the subject from the viewpoint of a gateway solution, this explicit the tunneling approach is inferior. It is simply suited for slightly different types of application, and most of the points describes for a gateway are equally valid. Vital mechanisms such as asynchronous notifications rarely exist as native protocol features and have to be replaced by workarounds outside the actual application.
