If it is normal, use a red light pen to test whether the cable is connected. Now, the LOS light is one you should pay special attention to. LOS stands for “Loss of Signal. ”. If you find that the Optical/Config/PON Light on your Fibre ONT (Optical Network Terminal) box is flashing, has gone off, or has gone red, this indicates there may be an issue with the fibre connection coming into your property. Start. If there are any signs of damage or loose connections, replace the transceiver and recheck the performance.
[pdf] This reference document provides information about HPE SAN architecture, including Fibre Channel, iSCSI, FCoE, SAN extension, and hardware interoperability. Storage architects and system administrators can use this document to plan, design, and maintain an HPE SAN. The QLogic® Fibre Channel (FC) portfolio offers best-in-class performance and functionality for storage area networks. Designed for rapid server deployment and orchestration, QLogic® products enable flexible operation with concurrent FCP and FC-NVMe. The information provided here is. A Fiber Channel SFP is a specialized optical transceiver designed exclusively for Fiber Channel (FC) networks, enabling high-speed, low-latency, and lossless data transmission in Storage Area Network (SAN) environments.
[pdf] 
