Juniper QFX5120 Series, Руководство по оборудованию

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Figure 26: Back-to-Front Airflow Through QFX5120-48Y Switch Chassis
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Ports FRUs
You must install only power supplies that have AIR IN labels in switches in which the fan modules have
AIR IN labels.
Do not mix power supplies and fan modules with different airflow labels (AIR IN and AIR OUT) in the same
chassis. If the fan modules have AIR IN labels, the power supplies must also have AIR IN labels; if the fan
modules have AIR OUT labels, the power supplies must also have AIR OUT labels.
The labels on the power supplies and fan modules should match the labels on the switch chassis.
Mixing components with AIR IN and AIR OUT 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 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 on the fan modules and power supplies, hot air exhausts through the vents on the front panel of
the switch.
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