Auto-Discovery for Universal Hardware

Auto-Discovery automatically detects cable types inserted into the U1 and U2 stacking port, and adjusts the configured speed of the port. Detection of stacking cables is performed during startup of the switch. Auto-Discovery is supported on ExtremeSwitching 5420 and 5520 series switches beginning in ExtremeXOS 31.5.

Auto-discovery operates on stack ports U1 and U2 on both 5420 and 5520 series switches. On 5420 series switches, the stack ports support either SFP+ or SFP-DD type cables. On 5520 series switches, the stack ports only support QSFP+ type cables.

For example, if a 5420 series switch is configured for Native V40 stacking and Auto-Discovery detects an SFP-DD cable present in either the U1 or U2 stack ports during start up, the stack port speed is automatically reconfigured for Native V80 (to match the speed of the SFP-DD cable).



Changing the stacking cables on an operational stack to achieve a different stack speed requires a reboot.

Supported Platforms

Auto-Discovery for Universal Hardware is supported on ExtremeSwitching 5420 and 5520 Series switches.

CLI Command

Auto-Discovery is enabled by default on the ExtremeSwitching 5420 and 5520 Series switches. Use the configure stacking-support auto-discovery [disable] command to disable Auto-Discovery for Universal Hardware.



Auto-Discovery is automatically re-enabled whenever the Universal Hardware is restored back to the factory configuration when the unconfigure switch all command is used.


The following limitations apply to Auto-Discovery for Universal Hardware: