The port mode determines the type of information shown by the port LEDs. I have a experience, the last week when I have encommended to find a cable in the rack, accidentally I hit the mode button with the "tracer pencil" and all trunk interfaces turn off their light and the rest of the interfaces looked like a christmas tree for a 30 seconds. It is typically a small, recessed button that can be pressed using a paperclip or similar small object. The Catalyst. The Mode button on a Cisco Catalyst switch is a physical interface element that allows network administrators to toggle through various operational states and diagnostic visualizations directly on the hardware's LED panel. The following describes the purpose of the LED indicators, and the meaning of their colors: System LED - Shows whether the system is receiving power and is functioning. When you press the Mode button to select the STACK LED, the corresponding port LEDs will blink green for each switch.
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