Troubleshoot the problem by following these steps: Confirm that both ports are not shut down. Check that the optical module model, wavelength, speed, and distance match. If the optical module is installed on a GE port, run the display interface GigabitEthernet x/x/x command to check information about the port, including the rate and wavelength. The SFP/Media Converter is designed for easy use in optical fiber transmission. There are no specific requirements for this document. This includes Doppler. First, the transmission class of the optical module fault investigation and solution method This type of optical module failure mainly includes port not UP, port status is UP but do not receive or send messages, port frequently up or down and CRC error.