Abstract: Set out from the evolution to all-optical transparent infrastructure and to service-orient characteristic, the researches on impairment-aware routing and wavelength assignment algorithms are surveyed and analyzed. Three new dynamic impairment-aware routing and wavelength assignment algorithms (IBest, IFF, IPack)are proposed through increasing the consideration of physical impairments effect on classic routing and wavelength assignment algorithms. The results from simulation show that the proposed algorithms both can maintain its competitive edge from corresponding classic ones and are superior to the classic ones in blocking probability in realistic circumstance with impairments.