Clearance Requirements For Airflow And Hardware Maintenance For Qfx5120 Switches - Juniper QFX5120 Series Hardware Manual

Table 28 on page 71 provides the cabinet requirements and specifications for the QFX5120 switch.
Table 28: Cabinet Requirements for the QFX5120 Switch
Cabinet Requirement
Cabinet size and clearance
Cabinet airflow requirements
Clearance Requirements for Airflow and Hardware Maintenance for
QFX5120 Switches
When planning the site for installing a QFX5120 switch, you must ensure sufficient clearance around the
switch. See Figure 35 on page 72
Follow these clearance requirements:
For the cooling system to function properly, the airflow around the chassis must be unrestricted.
If you are mounting the switch on a rack or cabinet along with other equipment, ensure that the exhaust
from other equipment does not blow into the intake vents of the chassis.
Leave at least 6 in. (15.2 cm) clearance in front of and behind the chassis for airflow.
Guidelines
The minimum cabinet size for accommodating a QFX5120 switch is 36 in.
(91.4 cm) deep. Large cabinets improve airflow and reduce the chance of
overheating.
When you mount the switch in a cabinet, ensure that ventilation through the
cabinet is sufficient to prevent overheating.
Ensure that the cool air supply you provide through the cabinet adequately
dissipates the thermal output of the switch (or switches).
Ensure that the cabinet allows the chassis hot exhaust air to exit the cabinet
without recirculating into the switch. An open cabinet (without a top or
doors) that employs hot air exhaust extraction from the top allows the best
airflow through the chassis. If the cabinet contains a top or doors,
perforations in these elements assist with removing the hot air exhaust.
The QFX5120 fans exhaust hot air either through the vents on the port
panel or through the fans and power supplies. Install the switch in the
cabinet in a way that maximizes the open space on the FRU side of the
chassis. This maximizes the clearance for critical airflow.
Route and dress all cables to minimize the blockage of airflow to and from
the chassis.
Ensure that the spacing of rails and adjacent cabinets allows for the proper
clearance around the switch and cabinet.
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