This patented technology predicts the channel quality of a lightpath based on how EDFAs are distributed along the lightpath and the number of channels that are lit up in the same fiber. The scheduling algorithm chooses the first available lightpath that can accommodate the requested transmission duration and does not overlap in time with other scheduled sessions on the same wavelength along a candidate path. The first available lightpath is then checked for quality using the models at times during the transmission session when there is a change of channel configuration (i.e. the number of channels that are lit up in a fiber). If the lightpath is not qualified at one or more times of change of channel configuration, the algorithm recursively starts the searching of the next first available lightpath starting from the time when the lightpath fails the quality check.