Juniper QFabric QFX3000-G Hardware Documentation page 224

QFX3000-G QFabric System Hardware Documentation
Table 52: N+0 DC Power Calculations for EX4300 Switch Configurations (continued)
Number of
Switch Power
Configuration Supplies
48-port EX4300 1
switch
2
N+N Redundancy Configuration of DC Power Supplies
174
Total Power (in
watts)
550
1100
You can configure your switch for N+N redundancy, in which N power supplies can be
removed or fail and the remaining N power supplies continue to supply power for the
switch without interruption.
You can configure the power management software to manage switch power for N+N
redundancy. When you configure power management for N+N redundancy, half of the
total power available (N) is held as reserve power while the other half (N) is available
for immediate consumption. If the switch configuration changes and requires additional
power, then additional power is drawn from the reserve power, and the switch no longer
has N+N power supply redundancy. This condition raises a minor alarm. If the condition
is not corrected within 5 minutes, then a major alarm is issued.
For more information about how power management allocates power to chassis
components when power is insufficient, see Understanding Power Management on EX
Series Switches.
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))
Backup power available = 0 W
A minor alarm is raised as switch has no N+N power supply redundancy.
If two power supplies are installed in the switch:
System power budget = (Output wattage of one power supply) – (5% of the output
wattage of one power supply)
System power budget = PSU(W) – (0.05 x PSU(W))
Backup power available = (Output wattage of one power supply) – (5% of the
output wattage of one power supply)
System power budget = PSU(W) – (0.05 x PSU(W))
Table 53 on page 175 lists the N+N power calculation for EX4300 switches that use 550 W
DC power supplies.
Usable System Backup Power
Power (in watts) (in watts)
550 0
1045 0
Copyright © 2018, Juniper Networks, Inc.
Base Power (in
watts)
175
175