Configuring Poe Power Management; Configuring Pd Power Management - 3Com 4500G Family Configuration Manual

Configuring PoE Power Management

Configuring PD Power Management

The power priority of a PD depends on the priority of the PoE interface. The priority levels of PoE
interfaces include critical, high and low in descending order. Power supply to a PD is subject to PD
power management policies.
All PSEs implement the same PD power management policies. When the PSE supplies power to a PD,
By default, no power will be supplied to a new PD if the PSE power is overloaded.
Under the control of a priority policy, the PD with a lower priority is first powered off to guarantee the
power supply to the new PD with a higher priority when the PSE power is overloaded.
19 watts guard band is reserved for each PoE interface on the device to prevent a PD from being
powered off because of sudden increase of the power of the PD. When the remaining power of the
interface is lower than 19 watts and no priority is configured for a PoE interface, the PSE does not
supply power to the new PD; when the remaining power of the interface is lower than 19 watts, but
priority is configured for a PoE interface, the interface with a higher priority can preempt the power
of the interface with a lower priority to ensure the normal working of the higher priority interface.
If the sudden increase of the power of the PD results in PSE power overload, power supply to the
PD on the PoE interface with a lower priority will be stopped.
If the guaranteed remaining PSE power (maximum PSE power – power allocated to the critical PoE
interface, regardless of whether PoE is enabled for the PoE interface) is lower than the maximum power
of the PoE interface, you will fail to set the priority of the PoE interface to critical. Otherwise, you can
succeed in setting the priority to critical, and this PoE interface will preempt the power of other PoE
interfaces with a lower priority level. In the latter case, the PoE interfaces whose power is preempted
will be powered off, but their configurations will remain unchanged. When you change the priority of a
PoE interface from critical to a lower level, the PDs connecting to other PoE interfaces will have an
opportunity of being powered.
Configuration prerequisites
Enable PoE for PoE interfaces.
Configuration procedure
Follow these steps to configure PD power management:
To do...
Enter system view
Use the command...
system-view
1-5
Remarks
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