1-6z 19 watts guard band is reserved for each PoE interface on the device to prevent a PD from beingpowered off because of a sudden increase of the PD power. When the remaining power of thePSE is lower than 19 watts and no priority is configured for the PoE interface, the PSE does notsupply power to the new PD; when the remaining power of the PSE is lower than 19 watts, butpriority is configured for the PoE interface, the interface with a higher priority can preempt thepower of the interface with a lower priority to ensure the normal working of the higher priorityinterface.z If the sudden increase of the PD power results in PSE power overload, power supply to the PD onthe PoE interface with a lower priority will be stopped to ensure the power supply to the PD with ahigher priority.If the guaranteed remaining PSE power (the maximum PSE power minus the power allocated to thecritical PoE interface, regardless of whether PoE is enabled for the PoE interface) is lower than themaximum 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 thepower of other PoE interfaces with a lower priority level. In the latter case, the PoE interfaces whosepower is preempted will be powered off, but their configurations will remain unchanged. When youchange the priority of a PoE interface from critical to a lower level, the PDs connecting to other PoEinterfaces will have an opportunity of being powered.Configuration prerequisitesEnable PoE for PoE interfaces.Configuration procedureFollow these steps to configure PoE interface power management:To do… Use the command… RemarksEnter system view system-view —Enter PoE interface view interface interface-typeinterface-number —Configure the power supplypriority for a PoE interface poe priority { critical | high | low } Optionallow by default.Configuring the PoE Monitoring FunctionAfter the PoE monitoring function is enabled, the system monitors the parameter values related to PoEpower supply, PSE, PD, and device temperature in real time. When a specific value exceeds thelimited range, the system will automatically take some measures to protect itself.
