Mdix Auto - Cisco Catalyst 3750 Command Reference Manual

Chapter 2 Catalyst 3750 Switch Cisco IOS Commands

mdix auto

Use the mdix auto interface configuration command on the switch stack or on a standalone switch 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 Auto-MDIX is enabled.
Command Modes Interface configuration
Command History Release
12.1(14)EA1
12.2(18)SE
Usage Guidelines When you enable Auto-MDIX on an interface, you must also set the speed and duplex on the interface
to auto so that the feature operates correctly.
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 and 10/100/1000-Mbps 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.
In releases earlier than Cisco IOS Release 12.2(18)SE, the default setting is disabled.
Examples This example shows how to enable Auto-MDIX on a port:
Switch# configure terminal
Switch(config)# interface gigabitethernet1/0/1
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.
78-16181-03
mdix auto
no mdix auto
Modification
This command was introduced.
The default setting changed from disabled to enabled.
Catalyst 3750 Switch Command Reference
mdix auto
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