Switch Port Status Indicators

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• When troubleshooting a suspected layer 1 or layer 2 problem:
  • check LED status indicators on the NIC and the switch/router
• need vendor documentation to interpret the LEDs
• may be two LEDs for status and for activity
  • or LED might use a mode button to show different information
• typical LED link states on a switch:
  • solid green—link is connected, but no traffic
  • flickering green—link is operating normally with traffic
    • blink rate indicates the link speed
  • no light—link is not working, or port is shutdown
  • blinking amber—a fault has been detected
    • duplex mismatch, excessive collisions, or redundancy check errors
  • solid amber—port is blocked by the spanning tree algorithm