Juniper EX4200 Series, Руководство по оборудованию, Страница: 58 / 344

Figure 19: DC Power Supply
To avoid electrical injury, follow instructions in Installing a Power Supply in an EX3200
Switch and Removing a Power Supply from an EX3200 Switch or “Installing a Power Supply
in an EX4200 Switch” on page 211 or “Removing a Power Supply from an EX4200 Switch”
on page 213 carefully.
PoE Power Budget and AC Power Supplies
The PoE power budget for a PoE switch model is determined by the capacity of its power
supply. For EX4200 switches, the capacity of the power supply provided with a PoE
model is sufficient to supply each PoE-capable port with up to 15.4 W in compliance with
the IEEE 802.3af PoE standard.
Table 12 on page 36 lists the power supply ratings, and
the associated PoE power budgets for EX4200 switch models that support PoE.
Starting with Junos OS Release 11.1, EX4200 switches support enhanced PoE, a Juniper
Networks extension to the IEEE 302.3af PoE standard. Enhanced PoE permits up to 18.6
W per PoE port. Because the power supply provided with a switch is designed to supply
a maximum of 15.4 W per PoE port, if you connect a powered device that draws more
than 15.4 W, the PoE power budget might not be sufficient to supply a full 15.4 W to the
remaining PoE ports.
NOTE: Switches upgraded to Junos OS Release 11.1 from a previous release
require a separate upgrade of the PoE controller software to enable enhanced
PoE support.
EX4200-24PX and EX4200-48PX switches support PoE+, the IEEE 802.3at PoE standard,
and permit up to 30 W per port.
Table 12: Power Supply Rating and PoE Power Budget for EX4200 Switch Models
PoE Power Budget Power Supply Rating
Number of PoE-enabled
Ports
Switch Model Number
130 W 320 W 8 EX4200-24T
130 W 320 W 8 EX4200-48T
Copyright © 2015, Juniper Networks, Inc. 36
EX4200 Switch Hardware Guide