HP ProCurve 2520 Power Priority Operation, How Is Power Allocation Prioritized, When Is Power Allocation Prioritized, Low, High, High, Critical

Power Over Ethernet (PoE) Operation

PoE Operation

Note	Depending on power demands, lower-priority ports on a switch with high PoE
	power demand may occasionally lose power due to the demands of higher-
	priority ports. (Refer to “Power Priority Operation” for further details.)

Power Priority Operation

In the default configuration PoE power priority is determined by port number, with the lowest numbered port having the highest priority.

When Is Power Allocation Prioritized?

If a PSE can provide power for all connected PD demand, it does not use its power priority settings to allocate power. However, if the PD power demand oversubscribes the available power, then the power allocation is prioritized to the ports that present a PD power demand. This causes the loss of power from one or more lower-priority ports to meet the power demand on other, higher-priority ports. This operation occurs regardless of the order in which PDs connect to the switch’s PoE-enabled ports.

How Is Power Allocation Prioritized?

There are two ways that PoE power is prioritized:

■Using a priority class method, a power priority of Low (the default), High, or Critical is assigned to each enabled PoE port.

■Using a port-number priority method, a lower-numbered port has priority over a higher-numbered port within the same configured priority class, for example, port A1 has priority over port A5 if both are configured with High priority.

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