PD Disconnect Precedence
After a PD is discovered and powered on an ExtremeSwitching
and Summit switch, the actual
power drain is continuously measured.
If
the usage for power by PDs is within the guard band, the system
begins denying power to PDs.
You can configure the switch to handle a request for power that exceeds
the power budget situation in one of two ways, called the disconnect precedence:
- Disconnect PDs according to the configured PoE (Power over Ethernet) port priority for each
PD.
- Deny power to the next PD requesting power, regardless of that
port‘s PoE priority. The default value is deny-port.
Port Priority Enabled
- When a PD is detected on a specific port, the PoE controller allows power on the port if
available power form the power source is greater than the maximum power threshold
configured on the port and the total allocated power is below the guard band.
- When available power is less than the maximum power threshold configured on the port and
port priority is less than the port priority set on all powered ports, the PoE controller
does not allow power on the port.
- When available power is less than the maximum power threshold configured on the port and
the port priority is greater than the priority of currently powered ports, the PoE
controller disconnects the two priority ports(s) and allows the port to power up.
- When the total consumed power exceeds the
configured power limit of the power source, the PoE controller disconnects the low
priority ports(s) and allows the port to power up.
Port Priority Disabled
- When a PD is detected on a specific port,
the PoE controller allows power on the port if available power from the power source is
greater than the maximum power threshold configured on the port and the total allocated
power is below the guard band. Note that "maximum power threshold" is the same as
"operator-limit".
- When available power is less than the maximum power threshold configured on the port,
the PoE controller does not allow power on this port.
- When the total consumed power exceeds the configured power limit of the power source,
the PoE controller starts powering down ports beginning with the highest port number.