Hi,

When automatic medium-dependent interface crossover (auto-MDIX) is enabled on an interface, the interface automatically detects the required cable connection type (straight through or crossover) and configures the connection appropriately. When connecting switches without the auto-MDIX feature, you must use straight-through cables to connect to devices such as servers, workstations, or routers and crossover cables to connect to other switches or repeaters. With auto-MDIX enabled, you can use either type of cable to connect to other devices, and the interface automatically corrects for any incorrect cabling. For more information about cabling requirements, see the hardware installation guide.

Auto-MDIX is enabled by default. When you enable auto-MDIX, you must also set the interface speed and duplex to auto so that the feature operates correctly. Auto-MDIX is supported on 10/100 and 10/100/1000-Mbps interfaces (for example on the 3750). It is not supported on 1000BASE-SX or -LX SFP module interfaces.

At least one side of the cables should be set to Auto-MDIX.

HTH,

Mohammed Mahmoud.