Optical Circuit Switching (OCS) technology is mostly used in all-optical network. Most OCS networks use WDM on fibers and one wavelength is assigned to one connection. However, OCS technology needs to pre-configure a light-path before transmitting data, and the pre-configuring overhead takes more than round trip time between the source node and destination node. This pre-configuring overhead also exists when the authors set up optical CDM paths on a wavelength of a WDM network. Therefore, when the data size is small, the influence of the pre-configuring overhead becomes large relatively.