Why must be PoE disabled when two switches that support PoE are connected together?

Aruba Employee
Aruba Employee

Product and Software: This article applies to all Aruba controllers that support Power Over Ethernet (PoE).


When you connect an Aruba controller that supports PoE to another device that also supports PoE, PoE must be disabled on both ends.


PoE might work on one or two Aruba controller ports, but it does not work on the other ports.


PoE must be disabled for these reasons:


  •  Both switches are powered by an external power supply, so PoE is not needed.
  •  If PoE is left on, the interface might be damaged because both parties are trying to supply power.

One symptom that Aruba has observed is that the interface on another vendor switch might be "flapping" when it is connected to an Aruba controller, which impacts user traffic.


The workaround is to disable PoE on both ports that connect the Aruba controller and the PoE switch. This workaround should be followed as the Aruba best practice.

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Last update:
‎07-02-2014 05:31 AM
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please descripe the term flapping
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