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.
Note
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
Cisco ASR 900 Series Aggregation Services Routers
.
Choose a proper location for the Cisco ASR 903 Router by following the guidelines listed below.
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:
• Use the
show environment all
command regularly to check the internal system status. The environmental
monitor continually checks the interior chassis environment; it provides warnings about high temperature
and creates reports on other potentially dangerous occurrences. If warning messages are displayed, take
immediate action to identify the cause, and correct the problem.
• Keep the Cisco ASR 903 Router off the floor and out of areas that collect dust.
• Follow ESD-prevention procedures to avoid damage to equipment. Damage from static discharge can
cause immediate or intermittent equipment failure.
Locating for Proper Airflow
Ensure that the Cisco ASR 903 Router location has enough airflow to keep the system operating within the
environmental characteristics and the air temperature is sufficient to compensate for the heat dissipated by
the system. For more information, see
Cisco ASR 903 and ASR 903U Aggregation Services Router Hardware Installation Guide
65
Preparing for Installation
Equipment Rack Guidelines