Core issue
When this issue occurs, the port LED does not light up. The status of the interface is down/down.
Resolution
To fix this issue, try these steps:
- Set the speed and duplex to AUTO.
- Enable the Auto-Medium-dependent Interface Crossover (MDIX) feature.
When this feature is enabled, the switch detects the required cable type for copper Ethernet connections and configures the interfaces accordingly. Therefore, either a crossover or a straight-through cable can be used for connections to a copper 10/100/1000 or 1000BASE-T SFP module port on the switch, regardless of the type of device on the other end of the connection. The Auto-MDIX feature is enabled by default on switches running Cisco IOS Release 12.2(18)SE or later. For releases between Cisco IOS Release 12.1(14)EA1 and 12.2(18)SE, the Auto-MDIX feature is disabled by default.
