The wavelength-routed networks with sparse and limited wavelength conversion capacity is considered in this work. After building the framework for dynamically setting up lightpaths, we propose a request-packet format embedded in signaling protocols to collect routes' status on the fly. Four lambda states $\emph{(non-idle; continuous-but-not-convertible idle; convertible-but-not-continuous idle; dual-idle)}$ are defined. These states are completely coded by 2 bits and updated into the proposed request-packet, providing full information picture of routes. By manipulating the collected information, a powerful wavelength assignment can be triggered, which provides enhancements for network performances. Analysis and simulation results show that our proposals outperform those of previous works in terms of blocking performance and complexity.
