QFX5120 Site Guidelines and Requirements

Environmental Requirements and Specifications for QFX5120 Switches

You must install the switch in a rack or cabinet. It must be housed in a dry, clean, well-ventilated, and temperature-controlled environment.

Follow these environmental guidelines:

The site must be as dust-free as possible, because dust can clog air intake vents and filters, reducing the efficiency of the switch cooling system.
Maintain ambient airflow for normal switch operation. If the airflow is blocked or restricted, or if the intake air is too warm, the switch might overheat, leading to the switch temperature monitor shutting down the device to protect the hardware components.

Table 1 provides the required environmental conditions for normal switch operation for QFX5120.

Table 1: QFX5120 Environmental Tolerances
Switch	Altitude	Relative Humidity	Temperature
QFX5120-32C	No performance degradation up to 16,404 feet (5000 meters)	Normal operation ensured in relative humidity range of 5% through 90%, noncondensing	Normal operation ensured in temperature range of 32° F through 104° F (0° C through 40° C) Nonoperating storage temperature in shipping container: –40° F through 158° F (–40° C through 70° C)
QFX5120-48T	No performance degradation up to 6000 feet (1829 meters)
QFX5120-48Y	No performance degradation up to 6000 feet (1829 meters)
QFX5120-48YM	No performance degradation up to 6000 feet (1829 meters)

Note:

Install the QFX5120 only in restricted-access areas, such as dedicated equipment rooms and equipment closets, in accordance with Articles 110-16, 110-17, and 110-18 of the National Electrical Code, ANSI/NFPA 70.

General Site Guidelines

Efficient device operation requires proper site planning and maintenance. It also requires proper layout of the equipment, rack or cabinet, and wiring closet.

To plan and create an acceptable operating environment for your device and prevent environmentally caused equipment failures:

Keep the area around the chassis free from dust and conductive material, such as metal flakes.
Follow the prescribed airflow guidelines to ensure that the cooling system functions properly. Ensure that exhaust from other equipment does not blow into the intake vents of the device.
Follow the prescribed electrostatic discharge (ESD) prevention procedures to prevent damaging the equipment. Static discharge can cause components to fail completely or intermittently over time.
Install the device in a secure area, so that only authorized personnel can access the device.

Site Electrical Wiring Guidelines

Table 2 describes the factors you must consider while planning the electrical wiring at your site.

Warning:

You must provide a properly grounded and shielded environment and use electrical surge-suppression devices.

Avertissement Vous devez établir un environnement protégé et convenablement mis à la terre et utiliser des dispositifs de parasurtension.

Table 2: Site Electrical Wiring Guidelines
Site Wiring Factor	Guidelines
Signaling limitations	If your site experiences any of the following problems, consult experts in electrical surge suppression and shielding: Improperly installed wires cause radio frequency interference (RFI). Damage from lightning strikes occurs when wires exceed recommended distances or pass between buildings. Electromagnetic pulses (EMPs) caused by lightning damage unshielded conductors and electronic devices.
Radio frequency interference	To reduce or eliminate RFI from your site wiring, do the following: Use a twisted-pair cable with a good distribution of grounding conductors. If you must exceed the recommended distances, use a high-quality twisted-pair cable with one ground conductor for each data signal, when applicable.
Electromagnetic compatibility	If your site is susceptible to problems with electromagnetic compatibility (EMC), particularly from lightning or radio transmitters, seek expert advice. Strong sources of electromagnetic interference (EMI) can cause: Destruction of the signal drivers and receivers in the device Electrical hazards as a result of power surges conducted over the lines into the equipment.

Rack Requirements for QFX5120 Switches

You can mount QFX5120 switches on a four-post 19-in. rack or a two-post 19-in. rack as defined in Cabinets, Racks, Panels, and Associated Equipment (document number EIA-310-D) published by the Electronics Industry Association.

Table 3 provides the rack requirements and specifications for QFX5120 switches.

Table 3: Rack Requirements and Specifications for QFX5120 Switches
Rack Requirements	Specifications
Type and strength	Use a four-post rack that provides bracket holes or hole patterns spaced at 1-U (1.75 in. or 4.45 cm) increments and that meets the size and strength requirements to support the weight. Use a two-post rack that provides bracket holes or hole patterns spaced at 1-U (1.75 in. or 4.45 cm) increments and that meets the size and strength requirements to support the weight. A U is the standard rack unit defined in Cabinets, Racks, Panels, and Associated Equipment (document number EIA-310–D) published by the Electronics Industry Association.
Size, airflow, and clearance requirements	If you are mounting a QFX5120-32C switch, ensure that the rack has a depth of 23.6 in. (60 cm). If you are mounting a QFX5120-48T, QFX5120-48Y, or QFX5120-48YM switch flush with the front posts of a rack, ensure that the distance between the front posts and the rear posts is between 27.5 in. (69.9 cm) and 30.5 in. (77.5 cm). If you are mounting a QFX5120-48T, QFX5120-48Y, or QFX5120-48YM switch in a recessed position from the front posts of a rack, ensure that the distance between the front posts and the rear posts is between 29.5 in. (75 cm) and 32.5 in. (82.6 cm). Ensure that the rack rails are spaced widely enough to accommodate the external dimensions of the switch chassis. The outer edges of the front-mounting brackets extend the width to 19 in. (48.26 cm). Route and dress all cables to minimize the blockage of airflow to and from the chassis. Ensure that the spacing of rails and adjacent racks allows for proper clearance around the switch and rack.
Connection to building structure	Secure the rack to the building structure. If your geographical area is earthquake-prone, secure the rack to the floor. Secure the rack to the ceiling brackets as well as wall or floor brackets for maximum stability.

Cabinet Requirements for QFX5120 Switches

You can mount QFX5120 switches in a cabinet that contains a four-post 19-in. rack as defined in Cabinets, Racks, Panels, and Associated Equipment (document number EIA-310-D) published by the Electronics Industry Association.

Table 4 provides the cabinet requirements and specifications for QFX5120 switches.

Table 4: Cabinet Requirements and Specifications for QFX5120 Switches
Cabinet Requirements	Specifications
Type and strength	Use a cabinet that is at least 36 in. (91.4 cm) deep. Large cabinets improve airflow and reduce the chance of overheating. The cabinet must contain a four-post rack that provides bracket holes or hole patterns spaced at 1-U (1.75 in. or 4.45 cm) increments and that meets the size and strength requirements to support the weight. A U is the standard rack unit defined in Cabinets, Racks, Panels, and Associated Equipment (document number EIA-310–D) published by the Electronics Industry Association.
Size, airflow, and clearance requirements	If you are mounting a QFX5120-32C switch, ensure that the rack inside the cabinet has a depth of 23.6 in. (60 cm). If you are mounting a QFX5120-48T, QFX5120-48Y, or QFX5120-48YM switch flush with the front posts of a rack inside the cabinet, ensure that the distance between the front posts and the rear posts is between 27.50 in. (69.9 cm) and 30.5 in. (77.5 cm). If you are mounting a QFX5120-48T, QFX5120-48Y, or QFX5120-48YM switch in a recessed position from the front posts of a rack inside the cabinet, ensure that the distance between the front posts and the rear posts is between 29.50 in. (75 cm) and 32.5 in. (82.6 cm). When you mount the switch in a cabinet, ensure that ventilation through the cabinet is sufficient to prevent overheating. Ensure that the cold air supply you provide through the cabinet adequately dissipates the thermal output of the switch (or switches). Ensure that the cabinet allows the hot exhaust air from the switch to exit the cabinet without recirculating into the chassis. 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 front panel or through the fan modules and power supplies. Install the switch in the cabinet in a way that maximizes the open space in front of or behind the chassis depending on the airflow direction inside 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.
Connection to building structure	Secure the cabinet to the building structure. If your geographical area is earthquake-prone, secure the cabinet to the floor. Secure the cabinet to the ceiling brackets as well as wall or floor brackets for maximum stability.

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 1 for clearance requirements for QFX5120-32C switches.
See Figure 2 for clearance requirements for QFX5120-48T switches.
See Figure 3 for clearance requirements for QFX5120-48Y switches.
See Figure 4 for clearance requirements for QFX5120-48YM switches.

Follow these clearance requirements:

For the cooling system to function properly, ensure that the airflow around the chassis is unrestricted.
If you are mounting the switch on a rack or cabinet along with other equipment, ensure that the hot air exhaust from other equipment does not blow into the cold air intake vents of the chassis.
Leave at least 6 in. (15.2 cm) clearance in front of and behind the chassis for airflow.
Leave at least 6 in. (15.2 cm) clearance on the left of the chassis for installing the grounding lug.
NEBS GR-63 recommends that you allow at least 30 in. (76.2 cm) in front of the rack or cabinet and 24 in. (61 cm) behind the rack or cabinet.
Leave at least 24 in. (61 cm) clearance in front of and behind the switch for service personnel to remove and install hardware components.

Figure 1: Clearance Requirements for Airflow and Hardware Maintenance for QFX5120-32C Switches

Figure 2: Clearance Requirements for Airflow and Hardware Maintenance for QFX5120-48T Switches

Figure 3: Clearance Requirements for Airflow and Hardware Maintenance for QFX5120-48Y Switches

Figure 4: Clearance Requirements for Airflow and Hardware Maintenance for QFX5120-48YM Switches

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