3Com S7902E, Configuration Manual

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1-8
Configuring PSE Power Management
Where the maximum PoE power may be lower than the sum of the maximum power required by all
PSEs, PSE power management is applied to decide whether to allow PSE to enable PoE, whether to
supply power to a specific PSE and the power allocation method. Where the maximum PoE power of
the device is higher than the sum of the maximum power required by all PSEs, it is unnecessary to
enable PSE power management.
When PoE supplies power to PSEs,
z
If PSE power management is not enabled, no power will be supplied to a new PSE when the PoE
power is overloaded.
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If PSE power management priority policy is enabled, the PSE with a lower priority is first
disconnected to guarantee the power supply to the new PSE with a higher priority when the PoE
power is overloaded.
The power supply priority levels of PSE include critical, high and low in descending order.
If the guaranteed remaining PoE power (maximum PoE power minus power allocated to the critical
PSE, regardless of whether PoE is enabled for the PSE) is lower than the maximum power of the PSE,
you will fail to set the power priority of the PSE to critical . Otherwise, you can succeed in setting the
power priority to critical , and this PSE will preempt the power of the PSE with a lower priority level. In
the latter case, the PSE whose power is preempted will be disconnected, but its configuration will
remain unchanged. After you change the priority of the PSE from critical to a lower level, other PSEs
will have an opportunity of being powered.
The guaranteed PoE power is used to guarantee that the key PSEs in the device can be supplied with
power all the time, without being influenced by the change of PSEs.
Follow these steps to configure PSE power management:
To do… Use the command… Remarks
Enter system view system-view —
Configure a PSE power
management priority policy
poe pse-policy priority
Required
Not configured by default.
Configure the power supply
priority for the PSE poe priority { critical | high |
low } pse pse-id
Optional
low by default.
Configuring PoE Interface Power Management
The power supply 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
PoE interface power management policies.