Install the switch in these types of cabinets and racks, assuming an external ambient air temperature range of 0 to 104°F (0 to 40°C):

• Standard perforated cabinets

• Solid-walled cabinets with a roof fan tray (bottom to top cooling)

• Standard open racks

Note	If you are using an enclosed cabinet, we recommend one of the thermally validated types, either standard perforated or solid-walled with a fan tray. We do not recommend using racks that have obstructions (such as power strips). The obstructions could impair access to field-replaceable units (FRUs).

The cabinet or rack must meet these requirements:

• Standard 19-inch (48.3 cm) (two- or four-post EIA cabinet or rack, with mounting rails that conform to English universal hole spacing per section 1 of ANSI/EIA-310-D-1992). For more information, see Requirements Specific to Perforated Cabinets.

  The spacing between the posts of the rack must be (EIA-310-D-1992 19-inch rack compatible) wide enough to accommodate the width of the chassis.

• The minimum vertical rack space requirement per chassis is:

  • For a one RU (rack unit) switch, 1.75 inches (4.4 cm)

  • For a one and a half RU (rack unit) switch, 2.63 (6.68 cm)

  • For a two RU (rack unit) switch, 3.5 inches (8.8 cm)

  • For a three RU (rack unit) switch, 5.25 inches (13.3 cm)

• The width between the rack-mounting rails must be at least 17.75 inches (45.0 cm) if the rear of the device is not attached to the rack. For four-post EIA racks, this measurement is the distance between the two front rails.

Four-post EIA cabinets (perforated or solid-walled) must meet these requirements:

• The minimum spacing for the bend radius for fiber-optic cables should have the front-mounting rails of the cabinet offset from the front door by a minimum of 3 inches (7.6 cm).

• The distance between the outside face of the front mounting rail and the outside face of the back mounting rail should be 23.0 to 30.0 inches (58.4 to 76.2 cm) to allow for rear-bracket installation.

  For the specific rack dimension information for each possible rack-mount, see Installation Options with Rack-Mount Kits.

If you are mounting the chassis in an open rack (no side panels or doors), ensure that the rack meets these requirements:

• The minimum vertical rack space per chassis must be equal to the rack unit (RU) of the chassis. One rack unit is equal to 1.75 inches (4.4 cm).

• The distance between the chassis air vents and any walls should be 2.5 inches (6.4 cm).

A perforated cabinet has perforations in its front and rear doors and side walls. Perforated cabinets must meet these requirements:

• The front and rear doors must have at least a 60 percent open area perforation pattern, with at least 15 square inches (96.8 square cm) of open area per rack unit of door height.

• The roof should be perforated with at least a 20 percent open area.

• The cabinet floor should be open or perforated to enhance cooling.

The Cisco R Series rack conforms to these requirements.

To help with cable management, allow additional space in the rack above and below the chassis to make it easier to route all of the fiber optic or copper cables through the rack.