•
When installing the routerouter in a back-to-back position with another device, ensure that there is a
minimum of 10 cm air flow clearance between the two devices.
•
If airflow through the equipment rack and the routers that occupy it is blocked or restricted, or if the
ambient air being drawn into the rack is too warm, an overtemperature condition may occur within the
rack and the routers that occupy it.
•
The site should also be as dust-free as possible. Dust tends to clog the router fans, reducing the flow of
cooling air through the equipment rack and the routers that occupy it, thus increasing the risk of an
overtemperature condition.
•
Enclosed racks must have adequate ventilation. Ensure that the rack is not congested because each router
generates heat. An enclosed rack should have louvered sides and a fan to provide cooling air. Heat that
is generated by the equipment near the bottom of the rack can be drawn upward into the intake ports of
the equipment above.
•
When mounting a chassis in an open rack, ensure that the rack frame does not block the exhaust fans.
•
When rack-installed equipment fails, especially equipment in an enclosed rack, try operating the equipment
by itself, if possible. Power off all the other equipment in the rack (and in adjacent racks) to give the
router maximum cooling air and clean power.
•
Avoid installing the router in a location in which the chassis air intake vents may draw in the exhaust
air from adjacent equipment. Consider how the air flows through the router; the airflow direction is front
to back, with ambient air drawn in from the vents located on the sides of the chassis.
Air Flow Guidelines for ETSI Rack Installation
To install a Cisco ASR 920 Series Router in a 2-post or 4-post rack, the front and rear doors of the cabinet
must be removed. It is recommended that you maintain a minimum clearance distance as mentioned below,
at all times.
•
front clearance
—
12.7 cm
•
rear clearance
—
14 cm
If you are mounting the chassis in a 4-post enclosed cabinet, ensure that you have a minimum of 14 cm of
clearance on each side of the chassis.
Floor Loading Considerations
Ensure that the floor under the rack supporting the Cisco ASR 920 Series Routers is capable of supporting
the combined weight of the rack and all the other installed equipment.
To assess the weight of a fully configured Cisco ASR 920 Series Router, see the
Cisco ASR-920-12SZ-IM
Router Specifications
table.
For additional information about floor loading requirements, see the
Building System (NEBS) Requirements: Physical Protection
document.
Cisco ASR-920-12SZ-IM Aggregation Services Router Hardware Installation Guide
26
Preparing for Installation
Air Flow Guidelines for ETSI Rack Installation
