Reflector node of an optical communication network, said reflector node comprising a port for inputting an optical signal sent by a monitoring node of the network over an optical link to the reflector node, the optical signal having a first wavelength range, wherein the reflector node comprises a wavelength selective optical reflector configured for generating a monitoring signal by reflecting a part of the optical signal back into the link, the monitoring signal having a second wavelength range that is a proper sub-range of the first wavelength range.