Determine the Affect of a Port on the Power Budget
The PoE power budget is affected differently depending on how PoE is enabled and whether a device is
connected:
1. When you configure a port with
is only allocated after you connect a device to the port.
•
When you connect a device, the maximum power for the device class is allocated if there is
sufficient power in the budget. See
•
If there is not enough power in the budget, the configuration is maintained and the port waits for
power to become available.
•
If the device advertises its power requirement through LLDP-MED, then FTOS allocates the
required amount and returns the remaining amount to the budget.
Note: LLDP-MED TLVs are only honored if the port is configured with
the
option).
max_milliwatts
2. When you configure a port with
only allocated after you connect a device to the port.
•
If the maximum power for the device class is less than the power limit you specified, FTOS
allocates the required amount and returns the remaining amount to the budget.
•
If there is not enough power in the budget, the configuration is maintained and the port waits for
power to become available.
•
If the maximum power for the device class is more than than the power limit you specified, FTOS
does not allocate any power.
Note: When a port is configured with
PoE device is disconnected, the allocated power is returned to the power budget.
3. When you configure a port with
FTOS allocates 15.4W (subject to availability and priority) to the port whether or not a device is
connected.
4. When you configure a port with
allocates the specified number of Watts.
•
If there is not enough power in the budget, the configuration is maintained and port waits for
power to become available.
•
If the maximum power for the device class is more than than the power limit you specified, FTOS
does not allocate any power.
power inline auto
without the
Table 36-1 on page
power inline auto
with the power limit option
(with or without the
power inline auto
power inline static
without the power limit option (
power inline static
with the power limit option (
power limit option, power
max_milliwatts
785.
power inline auto
max_milliwatts
max_milliwatts
max_milliwatts
max_milliwatts
Power over Ethernet | 791
(with or without
, power is
option) and the
),
), FTOS