PoE Power Management
Switches that have PoE ports have a PoE controller that keeps track of the PoE power
consumption on the switch and allocates power to the PoE ports. The following factors
determine how the PoE controller allocates power to the PoE ports:
•
PoE Power Budget on page 3304
•
Power Management Mode on page 3304
•
PoE Interface Power Priority on page 3305
PoE Power Budget
The PoE controller allocates power to the PoE ports from a set PoE power budget. The
PoE power budget varies according to switch model and, for switches that support power
supplies of different capacities, the capacity of the installed power supply. For example,
a Juniper Networks EX3200 Ethernet Switch with a 320 W power supply has a PoE power
budget of 130 W, while with a 600 W power supply it has a PoE power budget of 410 W.
In switches that support power supplies of different capacities, if you change your existing
power supply to a lower-capacity power supply, the PoE power budget might no longer
be sufficient to power all the PoE ports on the switch. If your switch supports redundant
power supplies and you have installed power supplies of different capacities, the PoE
power budget is based on the wattage of the lower-capacity power supply. The number
of PoE ports on the switch cannot be increased by installing a larger power supply.
You can display the PoE power budget for your switch by using the show poe controller
command.
Power Management Mode
EX Series switches support two power management modes: class and static. The mode
you configure for your switch determines how the maximum power for a PoE interface
is derived and how power is allocated to the PoE interfaces:
•
Class mode—In this mode, the maximum power for an interface is determined by the
class of connected powered device. Table 439 on page 3304 lists the classes of powered
devices and associated power levels.
Table 439: Class of Powered Device and Power Levels
Power Range of Powered
Device
Maximum Power
Delivered by PoE Port
Class
Standard
0.44 through 12.95 W
15.4 W
0
IEEE 802.3af (PoE)
and IEEE 802.3at
(PoE+)
0.44 through 3.84 W
4.0 W
1
3.84 through 6.49 W
7.0 W
2
6.49 through 12.95 W
15.4 W
3
12.95 through 25.5 W
30.0 W
4
IEEE 802.3at (PoE+)
Copyright © 2010, Juniper Networks, Inc.
3304
Complete Software Guide for Junos
®
OS for EX Series Ethernet Switches, Release 10.3
Summary of Contents for JUNOS OS 10.3 - SOFTWARE
Page 325: ...CHAPTER 17 Operational Mode Commands for System Setup 229 Copyright 2010 Juniper Networks Inc ...
Page 1323: ...CHAPTER 56 Operational Mode Commands for Interfaces 1227 Copyright 2010 Juniper Networks Inc ...
Page 2841: ...CHAPTER 86 Operational Commands for 802 1X 2745 Copyright 2010 Juniper Networks Inc ...
Page 3367: ...CHAPTER 113 Operational Mode Commands for CoS 3271 Copyright 2010 Juniper Networks Inc ...
Page 3435: ...CHAPTER 120 Operational Mode Commands for PoE 3339 Copyright 2010 Juniper Networks Inc ...
Page 3529: ...CHAPTER 126 Operational Mode Commands for MPLS 3433 Copyright 2010 Juniper Networks Inc ...