Reference Guide

Power over Ethernet (PoE) | 1137
Parameters
Defaults
none
Command Modes
INTERFACE
Command
History
Usage
Information
Power allocation is a function of per-port power priority settings, port TLVs, port IDs, which ports
request power first, and how much power is actually consumed by the active ports. Power priority is
allocated by this formula:
PoE_off_priority = static_or_auto_prio * 10000 + (user/LLDP-MED) priority * 1000 + slotId*100 + portId
where:
• static_prio = 0
• auto_prio = 1
The lower the value of PoE_off_priority for the selected port, the higher its power priority. So, if a port is
configured “static” (assigned a value of 0 in the formula), its priority is higher than a port configured as
“auto” (assigned a value of 1). Two ports with the same static/auto settings are then prioritized by their
user-set priorities and LLDP-MED values.
In a similar fashion, lower numbered slots/ports get a higher priority than higher numbered slots/ports.
For example, 0/1 has a higher priority than 1/10, which has a higher priority than 2/1. As the slot / port
number increases, the value of “PoE_off_priority” for the port increases and hence a lower priority.
Basically, priority is assigned in this order:
1 static/auto settings (using the power inline command)
2 user-set priorities (using this command)
3 LLDP-MED TLV, only if user priority is not configured (see Link Layer Detection Protocol
(LLDP).)
4 Slot ID (breaks tie of same-priority ports)
5 Port ID (breaks tie of same-priority ports in same slot)
Related
Commands
show power detail
c s
Display the total power consumption and power consumption by component.
Syntax
show power detail
critical Enter the keyword critical to set the PoE priority of the port to the highest level.
high Enter the keyword high to set the PoE priority of the port to the second highest level.
low Enter the keyword low to set the PoE priority of the port to the lowest level.
Version 7.7.1.0 Introduced on C-Series and S-Series
power inline Enable power to be supplied to a device connected to a port.
show power inline Display the ports that are enabled with PoE and the amount of power that
each is consuming.