The Cisco ONS 15216-OPM (Optical Performance Monitor) provides spectral measurement of dense wavelength division multiplexing (DWDM), which includes wavelength, power, and optical signal-to-noise ratio (OSNR) on a per-channel basis. Spectral parameters such as signal power, wavelength, and OSNR are measured and reported through CRAFT (RS-232) or Ethernet interfaces. This product is designed to monitor up to 40 individual optical channels in a single DWDM signal stream, and supports a channel spacing of 100 GHz or greater. The Cisco ONS 15216-OPM reports alarms based on user-provisionable thresholds.