Cisco Systems ASR 903 manual Equipment Rack Guidelines, Locating for Safety, 2-16

Chapter 2 Preparing for Installation

Site Planning

The distance between the center lines of the mounting holes on the two mounting posts must be 18.31 inches ± 0.06 inch (46.50 cm ± 0.15 cm). The rack-mounting hardware included with the chassis is suitable for most 19-inch equipment racks.

Consider installing the Cisco ASR 903 Router in a rack with the following features:

•Network Equipment Building System (NEBS) compliant, 19-inch (48.3 cm) wide rack.

•EIA or European Telecommunications Standards Institute (ETSI) hole patterns in the mounting rails. The required mounting hardware is shipped with the Cisco ASR 903 Router. If the rack that you plan to install the system in has metric-threaded rails, you must provide your own metric-mounting hardware.

•Perforated top and open bottom for ventilation to prevent overheating.

•Leveling feet for stability.

Note The Cisco ASR 903 Router should not be installed in an enclosed rack because the chassis requires an

unobstructed flow of cooling air to maintain acceptable operating temperatures for its internal components. Installing the router in any type of enclosed rack—even with the side doors removed—could disrupt the air flow, trap heat next to the chassis, and cause an overtemperature condition inside the router. If you use an enclosed rack, ensure that there are air vents on all sides of the rack and there is proper ventilation.

Equipment Rack Guidelines

The placement of the rack can affect personnel safety, system maintenance, and the system’s ability to operate within the environmental characteristics described in the “System Specifications” section on page 1-2. Choose a proper location for the Cisco ASR 903 Router by following the following guidelines.

Locating for Safety

If the Cisco ASR 903 Router is the heaviest or the only piece of equipment in the rack, consider installing it at or near the bottom to ensure that the rack’s center of gravity is as low as possible.

For additional information about the proper placement of electronic equipment, consult the document GR-63-CORE, Network Equipment Building System (NEBS) Requirements: Physical Protection.

Locating for Easy Maintenance

Keep at least 3 feet of clear space at the front and back of the rack. This space ensures that you can remove the Cisco ASR 903 Router components and perform routine maintenance and upgrades easily.

Avoid installing the Cisco ASR 903 Router in a congested rack and consider how routing of cables from other pieces of equipment in the same rack could affect access to the router cards.

The sides of the chassis must remain unobstructed to ensure adequate airflow and prevent overheating inside the chassis.

Allow the following clearances for normal system maintenance:

•At the top of the chassis—At least 3 inches (7.6 cm)

•Sides of the chassis—3 to 4 ft (91.44 cm to 121.92 cm)

To avoid problems during installation and ongoing operations, follow these general precautions when you plan equipment locations and connections:

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