Abstract: There is provided a control device for controlling a first transmission device and a second transmission device, the control device including a memory, and a processor coupled to the memory and the processor configured to set a first wavelength path between the first transmission device and the second transmission device, select a monitoring wavelength path from established wavelength paths allocated on a transmission line between the first transmission device and the second transmission device, monitor a signal quality of the monitoring wavelength path, and increase power of the first wavelength path, based on the signal quality of the monitoring wavelength path.

Abstract: There is provided an apparatus configured to estimate optical transmission performance in a transmission path of an optical signal, the apparatus including a memory, and a processor coupled to the memory and the processor configured to acquire a first index related to a first transmission performance of an optical signal transmitted through a span group between a first node and an n-th node and a second index related to a second transmission performance of an optical signal transmitted through a span or a span group between the first node and an m-th node, wherein n is an integer of 3 or more, and m is the integer satisfying m<n, and estimate a third index related to a third transmission performance of an optical signal to be transmitted through a span between the m-th node and the n-th node, based on the first index and the second index.