3com S7906E 설치 설명서

 

1-9 

All PSEs implement the same PoE interface power management policies. When a PSE supplies power 

to a PD, 

z 

If the PoE interface power management is not enabled, no power will be supplied to a new PD if 

the PSE power is overloaded. 

z 

If the PoE interface power management priority policy is enabled, the PD with a lower priority is 

first powered off to guarantee the power supply to the PD with a higher priority when the PSE 

power is overloaded. 

 

z 

19 watts guard band is reserved for each PoE interface 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 where the PoE interface resides is lower than 19 watts and no priority is configured for the 

PoE interface, the PSE does not supply power to the new PD; when the remaining power of the 

PSE where the PoE interface resides is lower than 19 watts, but priority is configured for the 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. 

z 

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. 

 

If the guaranteed remaining PSE power (the maximum PSE power minus the 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. 

Enable PoE for PoE interfaces. 

Follow these steps to configure PoE interface power management: 

Enter system view 

— 

Configure PoE interface power 
management priority policy 

Required 

Not configured by 
default. 

Enter PoE interface view 

interface interface-type 
interface-number 

—