Abstract: An optical communications network comprises optical data links comprising data channels. A time-domain sampled waveform of a selected data channel is obtained. The Fourier transform is applied to the time-domain sampled waveform of the selected data channel to generate a frequency-domain waveform of the selected data channel. Time-domain sampled waveforms of the selected data channels neighboring data channels are obtained. The Fourier transform is applied to the time-domain sampled waveforms of the neighboring data channels to generate frequency-domain waveforms of the neighboring data channels. The noise-to-signal ratio is calculated based on the frequency-domain waveforms. Based on the calculated noise-to-signal ratio, an optical signal to noise ratio (OSNR) penalty is estimated. A notification is generated when the OSNR penalty exceeds a predetermined threshold.

Abstract: A preFEC BER of a selected optical link is determined. A FEC Detected Degrade (FDD) threshold, FEC Excessive Degrade (FED) threshold, and FEC limit threshold are obtained for the selected optical link. The FDD threshold is less than the FED threshold and the FED threshold is less than the FEC limit. Based on the FDD threshold, FED threshold, the FEC limit, and a determination that a postFEC BER==0, it is determined whether a link down condition of the selected optical link can be asserted or de-asserted.

Abstract: A preFEC BER of a selected optical link is determined. A FEC Detected Degrade (FDD) threshold, FEC Excessive Degrade (FED) threshold, and FEC limit threshold are obtained for the selected optical link. The FDD threshold is less than the FED threshold and the FED threshold is less than the FEC limit. Based on the FDD threshold, FED threshold, the FEC limit, and a determination that a postFEC BER==0, it is determined whether a link down condition of the selected optical link can be asserted or de-asserted.

Abstract: An optical communications network comprises optical data links comprising data channels. A time-domain sampled waveform of a selected data channel is obtained. The Fourier transform is applied to the time-domain sampled waveform of the selected data channel to generate a frequency-domain waveform of the selected data channel. Time-domain sampled waveforms of the selected data channel's neighboring data channels are obtained. The Fourier transform is applied to the time-domain sampled waveforms of the neighboring data channels to generate frequency-domain waveforms of the neighboring data channels. The noise-to-signal ratio is calculated based on the frequency-domain waveforms. Based on the calculated noise-to-signal ratio, an optical signal to noise ratio (OSNR) penalty is estimated. A notification is generated when the OSNR penalty exceeds a predetermined threshold.