If possible, remove and reinstall the optical modules to check whether the fault is rectified. This document describes how to troubleshoot fiber optic interfaces by addressing some of the fiber optic module and cabling specifications. There are no specific requirements for this document. This includes Doppler. When optical modules operate on a switch, it is usually necessary to read the module's internal information to understand its working status—such as connection status and real-time metrics like optical power and temperature. Additionally, identifying module information helps detect coding. The triangle indicates the Tx (transmit) port with the pole facing outward on the SFP module, whereas the triangle indicates the Rx (receive) port with the bar facing inside. When connecting the SFP, we must ensure that Tx and Rx, or Tx –> Rx and Rx –> Tx, match on both sides. Usually, the port status failures are manifested as four types: the port is down (link failure), no packets received or sent when the port is up, unstable link, and CRC errors.
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