Administrator Guide

1. Power-inline mode: Class or Static
NOTE: Static ports have a higher weight than Class mode ports, so all static ports always stay on top of all class ports,
regardless of the other three parameters.
2. Power inline priority configuration
3. Link layer discovery protocol-media endpoint discovery (LLDP-MED) priority the power device (PD) sends in the Extended
Power-via-medium dependent interface (MDI) type, length, value (TLV) or the priority the PD sends in the IEEE 802.3at
power-via-MDI TLV
4. Port’s number
Within the set of static ports, the Dell Networking OS attempts to order the ports based on the second parameter, power inline
priority, the default of which is Low. If the Dell Networking OS finds multiple ports with the same power-inline priority, it breaks
the tie using the third parameter, the LLDP-MED Priority or power-via-mdi priority the PD advertises, which, like the power-
inline priority, can be Critical, High, or Low. If the Dell Networking OS still finds a tie, priority is based on the fourth
parameter, which is the ports position in the port extender; there cannot be a tie based on this parameter.
The Dell Networking OS dynamically sorts this list when:
● The power-inline mode or priority changes.
● The PD advertises a different LLDP-MED priority or power-via-mdi priority
● The PD is connected or disconnected
The Dell Networking OS always uses this sorted list of ports for allocation. When you add an extra PSU, additional ports are
powered based on this list. If you remove a power supply unit (PSU), this same list is used to remove power from the lowest
priority ports.
Determining the Affect of a Port on the Power Budget
The PoE and PoE+ power budget is affected differently depending on how you enable PoE and PoE+ and whether a device is
connected. The following lists these differences.
1. When you configure a port as power inline without setting the max_milliwatts power limit option, the Dell
Networking OS does not allocate any power to the port unless a device is connected and there is no limit to the amount of
power consumed by the powered device.
2. When you configure a port aspower inline with the max_milliwatts power limit option, the Dell Networking OS does
not allocate any power to the port unless a device is connected but restricts the maximum power that can be consumed by
the powered device to the amount set through the max_milliwatts option.
3. The max_milliwatts option has no effect on a port extender (PE) port when the PE port is configured to be in Class
mode.
Managing Power Priorities
PoE or PoE+ enabled port extender ports have power access priorities based first on the priority configured and then on their
port number.
The default priority is with respect to the port numbers, the lower port numbers have higher priorities when compared with
higher port numbers
You can augment the default prioritization using the [no] power inline {[max_milliwatts] | priority
{critical | high | low}} command, where critical is the highest priority and low is the lowest priority.
NOTE:
If you configure a priority with this command, the Dell Networking OS ignores any LLDP-MED priority on this port. If
you do not configure a port priority with this command, the Dell Networking OS honors any LLDP-MED priority.
In general, priority is assigned in this order:
1. power inline priority {critical | high | low} setting or priority advertised by LLDP TLV.power inline
mode pe pe—id stack-unit unit-number {class | static} setting:
NOTE:
The power inline static setting has a higher priority for access to power than those configured using the class
setting.
2. port number .
NOTE: By default, all ports are set to low priority.
756 Power over Ethernet (PoE)