Abstract: An optical transmission apparatus includes a detecting circuit configured to detect one or more empty slots in which a data signal is not accommodated in a plurality of slots included in a frame, a frame processing circuit configured to reduce size of the frame by deleting the one or more empty slots from the frame based on a detection result of the one or more empty slots and closing up gaps between remaining slots in the plurality of slots, and an optical modulation processing circuit configured to carry out multi-level modulation of the frame at a bit rate according to size of the frame after reduction.

Abstract: There is provided a line card configured to mount a module in which a signal transmitted on a line is processed, the line card including a memory, and a processor coupled to the memory and the processor configured to receive information on transmission quality of the signal to be transmitted through the module to be mounted on the line card, extract a combination satisfying the transmission quality among combinations of error correction processing schemes applicable to the module and a framer circuit for performing a signal processing for the signal to be transmitted, and estimate a combination of a range in which temperatures of each of the module and the framer circuit do not exceed a predetermined temperature when the module and the framer circuit are operated by applying the error correcting processing schemes of the combination extracted.