The autopolarity feature allows the system to detect and respond to the Ethernet cable type (straight-through or crossover cable) used to make the connection to the switch port or an endstation.
Turning off autopolarity applies only to the 10/100 BASE-T ports on the switch and copper medium on ExtremeSwitching combination ports.
When the autopolarity feature is enabled, the system causes the Ethernet link to come up regardless of the cable type connected to the port. When the autopolarity feature is disabled, you need either a crossover or a straight-through cable depending on the native polarity of the switch (it may vary across platforms) and the type of equipment being connected to the port. When disabling autopolarity, you have the option to set the port‘s polarity or Medium-Dependent Interface (MDI) mode to straight-through (MDI) or crossover (MDIX) mode irrespective of the native MDI mode of the port. The autopolarity feature is enabled by default.
Under certain conditions, you can choose to turn autopolarity off and set a specific MDI mode on one or more ports.