PD Disconnect Precedence

After a PD is discovered and powered on an ExtremeSwitching switch, the actual power drain is continuously measured.

If the usage for power by PDs is within the guard band, the system begins denying power to PDs.

You can configure the switch to handle a request for power that exceeds the power budget situation in one of two ways, called the disconnect precedence:

Disconnect PDs according to the configured PoE port priority for each PD.
Deny power to the next PD requesting power, regardless of that port‘s PoE priority. The default value is deny-port.

Port Priority Enabled

When a PD is detected on a specific port, the PoE controller allows power on the port if available power form the power source is greater than the maximum power threshold configured on the port and the total allocated power is below the guard band.
When available power is less than the maximum power threshold configured on the port and port priority is less than the port priority set on all powered ports, the PoE controller does not allow power on the port.
When available power is less than the maximum power threshold configured on the port and the port priority is greater than the priority of currently powered ports, the PoE controller disconnects the two priority ports(s) and allows the port to power up.
When the total consumed power exceeds the configured power limit of the power source, the PoE controller disconnects the low priority ports(s) and allows the port to power up.

Port Priority Disabled

When a PD is detected on a specific port, the PoE controller allows power on the port if available power from the power source is greater than the maximum power threshold configured on the port and the total allocated power is below the guard band. Note that "maximum power threshold" is the same as "operator-limit".
When available power is less than the maximum power threshold configured on the port, the PoE controller does not allow power on this port.
When the total consumed power exceeds the configured power limit of the power source, the PoE controller starts powering down ports beginning with the highest port number.