Computer network technologies were developed to transfer files between computers in 1960’s. Packet switching technology showed high efficiency for not only file transfer but also most of computer network applications. The needs from the market have driven to develop the various Internet technologies such as “Next Generation Internet” technologies and web service technologies. Nowadays market demands have been changing heavily its needs toward pervasive computing or ubiquitous computing. We’re concentrating our efforts to required network supports for pervasive computing. They are autoconfiguration of various networks such as ad-hoc network, sensor network, mobile network and semantic service discovery. We also are actively study overlay multicast for highly stable video stream service. Overlay network to enhance QoS is also being studied. Overlay networks are supposed to have less constraints for deployment in various network environments. Active network related researches are being conducted to find possible applications over broadband convergence networks.