What is the auto-MDIX feature on a switch?

• A. The automatic configuration of an interface for a straight-through or a crossover Ethernet cable connection
• B. The automatic configuration of an interface for 10/100/1000 Mb/s operation
• C. The automatic configuration of full-duplex operation over a single Ethernet copper or optical cable
• D. The ability to turn a switch interface on or off accordingly if an active connection is detected

Answer: (A)

Auto-MDIX lets a switch port automatically detect whether the connected Ethernet cable is straight-through or crossover and adjust its internal wiring so the transmit and receive pairs line up correctly. This means you can use either type of cable and the link will come up without you having to manually configure or swap ports. It’s about how the interface wires itself to match the other end, not about the speed of the link or whether the connection is duplex. Speed auto-negotiation and duplex settings are separate concepts, so those other options describe different behaviors. The essence of auto-MDIX is making cable type determination automatic to ensure proper communication.