Mdix Auto - Cisco Catalyst 3750 Metro Command Reference Manual

Chapter 2 Catalyst 3750 Metro Switch Cisco IOS Commands

mdix auto

Use the mdix auto interface configuration command to enable the automatic
medium-dependent-interface crossover (Auto-MDIX) feature on the interface. When Auto-MDIX is
enabled, the interface automatically detects the required cable connection type (straight-through or
crossover) and configures the connection appropriately. Use the no form of this command to disable
Auto-MDIX.
Syntax Description This command has no arguments or keywords.
Defaults The default is Auto-MDIX is enabled.
Command Modes
Interface configuration
Command History Release
12.1(14)AX
Usage Guidelines When you enable Auto-MDIX on an interface, you must also set the interface speed and duplex to auto.
When Auto-MDIX (along with autonegotiation of speed and duplex) is enabled on one or both of
connected interfaces, link up occurs, even if the cable type (straight through or crossover) is incorrect.
Auto-MDIX is supported on all 10/100 interfaces and on 10/100/1000BASE-T/TX small form-factor
pluggable (SFP) module interfaces. It is not supported on 1000BASE-SX or -LX SFP module interfaces.
ES ports do not support 10 or 100 Mbps operation. If a 1000BASE-T SFP module is inserted in an ES
Caution
module port, and you set the speed to auto to enable Auto-MDIX, be sure that the interface is connected
to a Gigabit interface. Setting the speed to auto can result in severe data loss if the interface is connected
to a 10/100 interface on another switch.
Examples This example shows how to enable Auto-MDIX on a port:
Switch# configure terminal
Switch(config)# interface fastethernet1/0/1
Switch(config-if)# speed auto
Switch(config-if)# duplex auto
Switch(config-if)# mdix auto
Switch(config-if)# end
You can verify the operational state of Auto-MDIX on the interface by entering the show controllers
ethernet-controller interface-id phy privileged EXEC command.
OL-9645-10
mdix auto
no mdix
Modification
This command was introduced.
Catalyst 3750 Metro Switch Command Reference
mdix auto
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