, a hierarchical multilevel network model first defined within the scope of computer integrated manufacturing (CIM) to cope with the anticipated complexity of data in a horizontally and vertically integrated communication environment. The original application target in the 1980s was factory and process automation. Numbers vary, but typically, this model comprised up to five levels [5]. While networks for the upper levels already existed by the time the pyramid was defined, the field level was still governed by point-to-point connections. Fieldbus systems were therefore also developed with the aim of finally bridging this gap. The actual integration of field-level networks into the rest of the hierarchy was considered in early standardization [3]; for most of the proprietary developments, however, it was never the primary intention.