Remove the SFP module from the slot. Clean any dust on the fiber patch or patch panel. When using a device with an SFP / RJ45 shared port, it may be necessary to specifically instruct it to use the SFP. Check whether the rates, duplex modes, and negotiation modes of optical ports at both ends are the same. You can run the following command to query the configuration of the local port. 1000Mb/s-speed mode, full-duplex mode, link type is auto negotiation Check. According to the optical module in the daily application of the switch on some of the problems, summed up a few points to eliminate the basic method of simple problems, the basic steps are as follows : 1. Check compatibility between the optical module and switch Most switch brands have specific compatibility requirements. Because SFP modules act as the physical interface between networking equipment and transmission media, verifying that a module is installed correctly and operating within its optical parameters is essential for maintaining stable network connectivity. The Cisco Small Business Series Switches allow you to plug in a Small Form-factor Pluggable (SFP) transceiver in their optical modules to connect fiber optic cables. SFP optical module failure usually occurs in two ways, the transmitting end and the receiving end.