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. The working rate, duplex mode, and. I have a strange problem I have not come across before, where one end of a fibre connection shows as "connected" but the other end shows as "not connected". I have a C2960-48PST-L connected to a C3750X-12S-E via OM4 fibre. Both switches use GLC-SX-MM SFP's which show as present when you do a "show. An optical module is a critical component in modern optical communication systems, directly affecting transmission stability, network reliability, and operational efficiency. However, during installation and daily operation, various issues may arise. 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.
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