DC Power Supply in QFX5120 Switches
QFX5120-32C, QFX5120-48T, and QFX5120-48Y switches support two 650-W AC or DC power supplies. Additionally, QFX5120-48T switches support 850-W high-voltage power supplies with AC or DC input. QFX5120-48YM switches support two 850-W AC or DC power supplies. The power supplies support front-to-back or back-to-front airflow. The power supplies are fully redundant, load-sharing, and hot-removable and hot-insertable FRUs when the second power supply is installed and running. You can remove and replace it without powering off the switch or disrupting switch functions. We ship QFX5120 switch models with two AC or DC power supplies preinstalled in the rear panel of the chassis. This topic describes the DC power supplies supported on QFX5120 switches.
Do not mix:
AC and DC power supplies in the same chassis.
650-W and 850-W power supplies in the same QFX5120-48T chassis.
Power supplies with different airflow directions in the same chassis.
Power supplies and fan modules with different airflow directions in the same chassis.
Characteristics of the DC Power Supply
You can install up to two power supplies in the power supply
slots in the rear panel of the QFX5120 switch chassis. On QFX5120-32C
switches, the slots are labeled PS0 and PS1. On QFX5120-48T, QFX5120-48Y, and QFX5120-48YM switches,
the slots are labeled 0 and 1 and have a power icon next to them.
You must install both the power supplies for optimal functioning of the switch.
If the switch is operational while you are replacing power supplies, you must remove only one power supply at a time.
Figure 1 shows the DC power supply for a QFX5120-32C switch.
Figure 2 shows the faceplate of a DC power supply for QFX5120-32C switches.
1 — Ejector lever | 3 — Power supply handle |
2 — LED | 4 — Input terminals |
Figure 3 shows the DC power supply for QFX5120-48T and QFX5120-48Y switches.
1 — Input terminals | 3 — Ejector lever |
2 — Protective earthing terminal | 4 — Power supply handle |
Figure 4 shows the DC power supply for QFX5120-48YM switches.
1 — Power supply handle | 3 — Ejector lever |
2 — Input terminals |
Figure 5 shows the faceplate of a DC power supply for QFX5120-48T, QFX5120-48Y, and QFX5120-48YM switches.
1 — Negative Input terminals | 6 — Fault LED (labeled !) |
2 — Positive Input terminals | 7 — Out LED (labeled OUT) |
3 — Terminal cover | 8 — In LED (labeled IN) |
4 — Ejector lever | 9 — Power supply handle |
5 — Protective earthing terminal |
Table 1 lists the specifications of the DC power supplies used in QFX5120 switches.
Table 1: Specifications of the DC Power Supplies Used in QFX5120 Switches
Item | Specifications |
|---|---|
Model number |
|
Field-replaceable unit (FRU) type | Hot-insertable and hot-removable |
Weight |
|
Minimum installed in chassis | 1 |
Maximum installed in chassis | 2 |
Power supply slots |
|
Fans | Internal |
Airflow |
|
Power supply status LEDs |
|
To prevent electrical injury while installing or removing DC power supplies, carefully follow instructions in Connect Power to a DC-Powered QFX5120 Switch and Maintain the QFX5120 Power System.
DC Power Supply Airflow
Each power supply has its own fan and is cooled by its own internal cooling system.
Verify that the airflow direction in the power supplies matches the airflow direction in the fan modules. Ensure that each power supply that you install in the chassis has the same airflow direction. If you install power supplies with two different airflow directions, Junos OS raises an alarm. If you need to change the airflow direction in a chassis, you must replace all the fan modules and power supplies with the other airflow direction and update the installation base (see Register Products—Mandatory to Validate SLAs).
Table 2 lists the DC power supply models and the direction of airflow in them. The power supplies have color-coded handles and labels that indicate the direction of the airflow.
Table 2: Airflow Direction in DC Power Supplies for QFX5120 Switches
Model | Color of the Power Supply Handle | Label | Direction of Airflow |
|---|---|---|---|
QFX5120-32C— | Red |
| Front-to-back—Cold 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. |
QFX5120-48T | Juniper Gold |
| |
QFX5120-48YM— | Juniper Gold |
| |
QFX5120-32C— | Blue |
| Back-to-front—Cold 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. |
QFX5120-48T | Juniper Azure Blue |
| |
QFX5120-48YM— | Juniper Azure Blue |
|