Traditional but proprietary infrastructure networks for building control and facility automation, such as LON, EIB, etc., can lead to dif.culties and costly gateway structures in approaches of integrating them into wider intranets and the internet. "SmartIP devices", i.e. small sub-computer nodes with fully integrated IP stack, have been developed and deployed. They provide not only a replacement, but additionally open a large range of new application areas. Small devices with actuators and sensors, for in/output, and local positioning systems, providing an IP socket connection and an optional HTTP server, are programmed in Java as "internet appliances". Self-configuration and ad hoc networking mechanisms allow user-friendly plug-and-play operation. Cabling cost is reduced by supplying electricity via "Power over Ethernet" (no power cable); or by connecting them wirelessly (no network cable). With the aim of Seamless Networking, "Gateway-less" or "Zero-gateway" structures become possible. The user benefits from ubiquitous networking support in daily routines, e.g. the transition between home - car - office.