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

Table 66: N+0 DC Power Calculations for EX4300 Switch Configurations
Number of
Switch Power
Configuration Supplies
24-port EX4300 1
switch
2
32-port EX4300 1
switch
2
48-port EX4300 1
switch
2

N+N Redundancy Configuration of DC Power Supplies

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)
Total Power (in Usable System
watts) Power (in watts)
550 550
1100 1045
550 550
1100 550
550 550
1100 1045
Backup
Power (in Base Power (in
watts) watts)
0 150
0 150
0 149
550 160
0 175
0 175
188