Management of communication by on-line routing in new FPGAs with a large amount of logic resourcesand partial reconfigurability is a new challenging problem. A Network-on-Chip (NoC) typically uses packet routing mechanism, which has often unsafe data transfers, and network interface overhead. In this paper, circuit routing for such dynamic NoCs is investigated, and a practical 1-dimensional network with an efficient routing algorithm is proposed and implemented. Also, this concept has been extended to the 2-dimensional case. The implementation results show the low area overhead and high performance of this network.