Bi-directional lightpath reconfiguration performance has been evaluated experimentally for regional IP-over-wavelength-division multiplexing network applications, making the network scalable and stable when traffic changes occur. The reconfiguration performance was examined in an experimental network with reconfigurable optical add/drop multiplexers (ROADMs) to connect four nodes with bi-directional dual-fibers. The experiment was conducted by controlling the ROADMs. The control signals were sent by a developed system. The lightpaths were added or deleted by the control system in the experimental network, and IP packets were monitored. The results clarified that lightpaths could be reconfigured by controlling the ROADMs, and IP packets could be routed dynamically by Open Shortest Path First so as to adapt the lightpath changes. The reconfiguration functions of the system together with the ROADMs provide network administrators with easy management of the network in a skill-less, centralized and remotely controlled way. Copyright © 2009 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.