H3C Technologies H3C WX3000E Series Wireless Switches - Manual (Page 452)

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Item Description
Power Priority
Set the power supply priority for a PoE port. The priority levels of a PoE port include low,
high, and critical in ascending order.
• When the PoE power is insufficient, power is first supplied to PoE ports with a higher
priority level.
• When the PSE power is overloaded, the PoE port with a lower priority is first
disconnected to guarantee the power supply to the PD with a higher priority.
• If you set the priority of a PoE port to critical, the system compares the guaranteed
remaining PSE power (the maximum PSE power minus the maximum power allocated
to the existing critical PoE port, regardless of whether PoE is enabled for the PoE port)
with the maximum power of this PoE port. If the former is greater than the latter, you can
succeed in setting the priority to critical, and this PoE port will preempt the power of
other PoE ports with a lower priority level; otherwise, you will fail to set the PoE port to
critical. In the former case, the PoE ports whose power is preempted will be powered
off, but their configurations will remain unchanged. When you change the priority of a
PoE port from critical to a lower level, the PDs connecting to other PoE ports will have
an opportunity of being powered.
By default, the power priority of a PoE port is low.
IMPORTANT:
• 19 watts guard band is reserved for each PoE port on the device to prevent a PD from
being powered off because of a sudden increase of the PD power. When the
remaining power of the PSE is lower than 19 watts, the port with a higher priority can
preempt the power of the port with a lower priority to ensure the normal working of the
higher priority port.
• If the sudden increase of the PD power results in PSE power overload, power supply to
the PD on the PoE interface with a lower priority will be stopped to ensure the power
supply to the PD with a higher priority.
Configuring non-standard PD detection
There are standard PDs and nonstandard PDs. Standard PDs are those conforming to the IEEE 802.3af
standard. Usually, the PSE can detect only standard PDs and supply power to them. The PSE can detect
nonstandard PDs and supply power to them only after the PSE is enabled to detect nonstandard PDs.
1. Select PoE > PoE from the navigation tree.
2. Click the PSE Setup tab to enter the page shown in Figure 427 . The page displays the location of
all PSEs, and the status of the non-standard PD detection function.
Figure 427 PSE Setup tab
3. To enable the non-standard PD detection function of a specified PSE:
a. Select Enable in the corresponding Non-Standard PD Compatibility column of the target PSE.