Understanding Guard Band - Nokia Alcatel-Lucent OmniSwitch 6360 Hardware User's Manual

Managing Power over Ethernet (PoE)

Understanding Guard Band

Guard Band functionality is implemented when the switch has to provide power to a newly connected PD. This
functionality is more relevant on switches that have a lower amount of total PoE power available for the switch
but a higher default maximum PoE power available to some ports.
• If the amount of power remaining is less than the port's configured maximum PoE power value or the PD's
class maximum power then the switch will not power up the PD.
• This applies even if the newly connected PD actually requires less than the maximum power available for
the port.
For example, assume the following:
• There is 50W of PoE power remaining on the switch.
• A newly connected PD only requires 4W of power.
• The port's maximum PoE power value is 75W.
In this example the newly connected PD will not be powered on since the port's maximum PoE power value is
greater than the PoE power remaining on the switch.
To allow the PD to be powered, the port's maximum PoE value can be configured to be less than the power
remaining by issuing the following command to set the port's maximum PoE power to 10W:
-> lanpower power 1/1/1 power 10000
Using the previous example:
• There is 50W of PoE power remaining on the switch.
• A newly connected PD only requires 4W of power.
• The port's maximum PoE power value is now 10W.
The newly connected PD will be powered on since the port's maximum PoE power value is now less than the
PoE power remaining on the switch. The examples assume the new PD has the same or lower priority as the
existing PDs, otherwise priority disconnect will override.
The Guard Band functionality does not apply to PDs that are already powered up. However, priority disconnect
will apply if there's not enough power to power all PDs in the case of the power budget being reduced, such as
the removal of a power supply.
Please refer to the "Understanding Priority Disconnect" on page 4-10
OmniSwitch 6360 Hardware Users Guide April 2021
Understanding Guard Band
for additional details.
page 4-9