The switch s optical module has two LEDs

A switch's optical module typically has two LEDs: one indicating link status and the other indicating activity or data transmission.LED Functions

Most optical modules, such as SFP or CFP modules, have two primary LEDs:

• Link/Status LED: This LED shows whether the optical module is properly connected and recognized by the switch. A solid green usually indicates the port is online and functioning correctly, while amber or off may indicate no link, a fault, or that the module is not properly seated .
• Activity/Transmit-Receive LED: This LED indicates data transmission or reception. It may blink when frames are being sent or received over the fiber optic link. Continuous blinking reflects normal traffic, while no blinking may indicate inactivity or a disconnected cable .

LED Color and Behavior

• Green LED: Typically indicates normal operation, link established, and proper module function.
• Amber LED: Often signals a warning, such as a module fault, misconfiguration, or environmental issue.
• Blinking vs. Solid: Blinking usually represents active data transfer, while solid indicates a stable link or status condition .

Practical Notes

• Ensure the optical module is fully seated in the switch port and the fiber cable is properly connected.
• If the link LED is off, check the module type, compatibility, and switch firmware.
• If the activity LED does not blink despite traffic, verify the network configuration and cable integrity.
• Some modules may have internal diagnostics, and LED patterns can vary slightly depending on the manufacturer or module type . Understanding these LEDs helps in troubleshooting connectivity issues, monitoring network activity, and confirming that the optical module is operating correctly.