Nowadays many new technologies are being developed and introduced for Internet, home networks, and sensor networks. The new technologies must be evaluated in detail before deployment. However the above mentioned networks have a large number of nodes, and a complicated topology. We developed a large-scale, realistic and real-time network testbed, StarBED, using hundreds of PCs, and switched networks. We are now implementing StarBED2, which expands StarBED so as to be suitable for emulating ubiquitous networks. In this paper we describe StarBED2, its design policy, architecture, and additional components, including the custom experiment- support system, RUNE (real-time ubiquitous network emulation environment). We then show some experimental results obtained in this environment with emulated networked sensing systems.