The solution is to unplug the fiber and reinsert it into the SFP module interface until a “click” sound is heard, indicating the fiber connector and SFP module are properly connected. Contamination or damage on the fiber end face requires the use of a fiber end-face. Before troubleshooting the issue, please look at our 16 tips for troubleshooting your optical transceiver connections. When the connection does not work as expected after we set it up according to the Installation Guide, we need to do some troubleshooting. I noticed something odd with a fiber SFP module. When it's plugged in, there's no light visible from the transmitter. To compare, I checked another working SFP — the TX light is visible immediately, and the RX/TX power levels look. 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.
[PDF Version]