N+0 Redundancy Configuration Of Dc Power Supplies - Juniper QFX5110 Series Hardware Documentation

Table 65 on page 187 lists the DC power supply models and the direction of airflow in them.
Table 65: Airflow Direction in DC Power Supply Models for EX4300 Switches
Model
JPSU-550-DC-AFO-A
JPSU-550-DC-AFI-A

N+0 Redundancy Configuration of DC Power Supplies

In an N+0 redundancy configuration, no power is reserved for resiliency regardless of number of power
supplies installed in the switch.
Depending on the power supplies installed in the switch, you can determine the system power budget.
If one power supply is installed in the switch:
System power budget = Output wattage of the installed power supply (PSU(W))
If two power supplies are installed in the switch:
System power budget = (Sum of the output wattage of the two power supplies) – (10% of the output
wattage of the installed power supply)
System power budget = PSU
Table 66 on page 188 lists the N+0 power calculation for EX4300 switches that use 550 W DC power
supplies.
NOTE: The DC power supply in the switch does not support Power over Ethernet (PoE); you
can use either an external power injector or an AC power supply to supply power to PoE devices
that you connect to the switch. 32-port EX4300 switches does not support Power over Ethernet
(PoE).
Label on Power
Supply Direction of Airflow
AIR OUT (AFO) Front-to-back—that is, air intake to cool the chassis is through the
vents on the front panel of the chassis and hot air exhausts through
the vents on the rear panel of the chassis.
AIR IN (AFI) Back-to-front—that is, air intake to cool the chassis is through the
vents on the rear panel of the chassis and hot air exhausts through
the vents on the front panel of the chassis.
(W) + PSU (W) – (0.10 x (PSU(W))
0 1
187