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QFX5120 Cooling System

 

QFX5120 Cooling System

The cooling system in a QFX5120 device consists of fan modules and the fans that are part of the power supplies. The QFX5120-32C has six fan modules, and the QFX5120-48Y has five fan modules. You can order a QFX5120 that works in one of two airflow directions. The airflow direction depends on the fan modules and power supplies that are installed in the switch. QFX5120 switches provide back-to-front airflow (air enters through the back of the switch), indicated by the label AIR IN, or front-to-back (air exhausts through the back of the switch), indicated by the label AIR OUT—depending on the fan modules and power supplies installed in the switch.

Caution

You must not mix fan modules and power supplies with different airflow directions in the same chassis.

QFX5120 Cooling System

QFX5120-48Y switches are shipped with five fan modules (4+1 redundancy) preinstalled at the rear of the chassis. QFX5120-32C switches are shipped with six fan modules (5+1 redundancy) preinstalled at the rear of the chassis. These fan modules are designed for one of the two available airflow directions (Airflow In or Airflow Out). The fan modules are also color-coded according to the airflow direction.

Figure 1 shows the QFX5120-32C fan module.

Figure 1: QFX5120-32C -AFI Fan Module
QFX5120-32C -AFI Fan Module

Figure 2 shows the QFX5120-48Y fan module.

Figure 2: QFX5120-48Y-AFI Fan Module
QFX5120-48Y-AFI Fan Module

For QFX5120-32C, the six fan modules are numbered 0 through 5 counting from left to right. For QFX5120-48Y, the five fan modules are numbered 0 through 4 counting from left to right. Each fan module slot has a fan icon and an LED next to it.

Caution

Do not mix:

  • Fan modules with different airflow labels (AIR IN and AIR OUT) in the same chassis.

  • Power supplies with different airflow labels (AIR IN and AIR OUT) in the same chassis.

  • Fan modules and power supplies with different airflow labels (AIR IN and AIR OUT) in the same chassis.

While replacing fan modules, you must remove only one fan module at a time from the rear panel of the chassis. The switch continues to operate for a limited period of time (30 seconds) without thermal shutdown while a fan module is being replaced..

Note

All the fan modules must be installed for optimal functioning of the switch.

The fan modules are available in two models that have different airflow directions.

  • Back-to-front (air enters through the back of the switch), indicated by label AIR IN and azure blue color

  • Front-to-back (air exhausts through the back of the switch), indicated by label AIR OUT and gold color.

QFX5120 Models and Airflow Direction

Table 1 shows the airflow direction in QFX5120 switch models.

Table 1: Airflow Direction in QFX5120 Switch Models

Model Number

Fan Modules and Power Supply

Color of the Fan Module

Direction of Airflow in the Fan Module

Power Supplies

QFX5120-32C-AFO

The switch ships with six fan modules and two AC power supplies, each with a label AIR OUT.

Juniper Gold

Front-to-back—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.

For switches that have fan modules with the AIR OUT label, you must install only power supplies that have theAIR OUT) label.

QFX5120-32C-AFI

The switch ships with six fan modules and two AC power supplies, each with a label AIR IN.

Juniper Azure Blue

Back-to-front—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.

For switches that have fan modules with the AIR IN label, you must install only power supplies that have theAIR IN) label.

QFX5120-48Y-AFO

The switch ships with five fan modules and two AC power supplies, each with a label AIR OUT.

Juniper Gold

Front-to-back—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.

For switches that have fan modules with the AIR OUT label, you must install only power supplies that have theAIR OUT) label.

QFX5120-48Y-AFI

The switch ships with five fan modules and two AC power supplies, each with a label AIR IN.

Juniper Azure Blue

Back-to-front—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.

For switches that have fan modules with the AIR IN label, you must install only power supplies that have theAIR IN) label.

QFX5120-48Y-DC-AFO

The switch ships with five fan modules and two DC power supplies, each with a label AIR OUT.

Juniper Gold

Front-to-back—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.

For switches that have fan modules with the AIR OUT label, you must install only power supplies that have theAIR OUT) label.

QFX5120-48Y-DC-AFI

The switch ships with five fan modules and two DC power supplies, each with a label AIR IN.

Juniper Azure Blue

Back-to-front—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.

For switches that have fan modules with the AIR IN label, you must install only power supplies that have theAIR IN) label.

Caution

Do not mix:

  • AC and DC power supplies in the same chassis.

  • Fan modules and power supplies with different airflow directions in the same chassis.

  • Power supplies and fan modules with different airflow labels (AIR IN and AIR OUT) in the same chassis.

QFX5120 Models with Front-to-Back Airflow

In the QFX5120 switch models that have front-to-back airflow, the air intake to cool the chassis is through the vents on the front panel of the switch and hot air exhausts through the vents on the rear panel.

Figure 3 shows the front-to back airflow through the QFX5120-32C switch chassis.

Figure 3: Front-to-Back Airflow Through QFX5120-32C Switch Chassis
Front-to-Back Airflow Through
QFX5120-32C Switch Chassis

Figure 4 shows the front-to-back airflow through the QFX5120-48Y switch chassis.

Figure 4: Front-to-Back Airflow Through QFX5120-48Y Switch Chassis
Front-to-Back Airflow Through
QFX5120-48Y Switch Chassis

You must install only power supplies that have AIR OUT (AFO) labels in switches in which the fan modules have AIR OUT (AFO) labels.

QFX5120 Models with Back-to-Front Airflow

In the QFX5120 switch models that have back-to-front airflow, the air intake to cool the chassis is through the vents on the rear panel and hot air exhausts through the vents on the front panel of the switch.

Figure 5 shows the back-to-front airflow through QFX5120-32C switch chassis.

Figure 5: Back-to-Front Airflow Through QFX5120-32C Switch Chassis
Back-to-Front Airflow Through
QFX5120-32C Switch Chassis

Figure 6 shows the back-to-front airflow through the QFX5120-48Y switch chassis.

Figure 6: Back-to-Front Airflow Through QFX5120-48Y Switch Chassis
Back-to-Front Airflow Through
QFX5120-48Y Switch Chassis

You must install only power supplies that have AIR IN (AFI) labels in switches in which the fan modules have AIR IN (AFI) labels.

Do not mix power supplies and fan modules with different airflow labels (AIR IN (AFI) and AIR OUT (AFO)) in the same chassis. If the fan modules have AIR IN (AFI) labels, the power supplies must also have AIR IN (AFI) labels; if the fan modules have AIR OUT (AFO) labels, the power supplies must also have AIR OUT (AFO) labels.

The labels on the power supplies and fan modules should match the labels on the switch chassis.

Mixing components with AIR IN (AFI) and AIR OUT (AFO) labels in the same chassis hampers the performance of the cooling system of the switch and leads to overheating of the chassis.

Caution

The system raises an alarm if a fan module fails or if the ambient temperature inside the chassis rises above the acceptable range. If the temperature inside the chassis rises above the threshold temperature, the system shuts down automatically.

Positioning the Switch

In front-to-back airflow, indicated by the label AIR OUT (AFO) on the fan modules and power supplies, hot air exhausts through the vents on the rear panel of the switch. In back-to-front airflow, indicated by the label AIR IN (AFI) on the fan modules and power supplies, hot air exhausts through the vents on the front panel of the switch.

In data center deployments, position the switch in such a manner that the AIR IN (AFI) labels on switch components are next to the cold aisle, and AIR OUT (AFO) labels on switch components are next to the hot aisle.

QFX5120 Fan Module Status

Each switch has a status LED for each fan module next to the fan module slot on the rear panel of the chassis. The Status LED indicates the status of the fan module. Table 2 describes the Status LED on the fan module in an QFX5120 switch.

Table 2: Fan Module Status LED

LED

Color

State

Description

Status

Green

On steadily

The fan module is functioning normally.

Amber

Blinking

An error has been detected in the fan module. Replace the fan module as soon as possible. Either the fan has failed or it is seated incorrectly. To maintain proper airflow through the chassis, leave the fan module installed in the chassis until you are ready to replace it.

Under normal operating conditions, the fan modules operate at a moderate speed. Temperature sensors in the chassis monitor the temperature within the chassis.

The system raises an alarm if a fan module fails or if the ambient temperature inside the chassis rises above the acceptable range. If the temperature inside the chassis rises above the threshold temperature, the system shuts down automatically.