Cisco 12008, Руководство по установке и настройке, Страница: 112 / 382

Site Requirements Guidelines
Cisco 12008 Gigabit Switch Router Installation and Configuration Guide 2-10
Air Flow Guidelines
The Cisco 12008 air circulation system includes two fan trays:
•
Card cage fan tray—This router component is located behind the air filter assembly (see
Figure 2-2).
The card cage fan tray draws ambient air through a removable and serviceable air filter
assembly in the front of the router, passes it over the switch fabric cards in the lower
card cage, directs it upward through the circuit boards in the upper card cage, and
exhausts it through vents at the top rear of the router enclosure (see Figure 2-4).
•
Power supply fan tray—This router component is located at the bottom of the power
supply bay (see Figure 2-3).
The power supply fan tray draws ambient air through its faceplate, directs the air upward
through the power supply bays, and exhausts it through vents at the top rear of the router
enclosure (see Figure 2-4).
To ensure adequate air flow through the router’s internal components, it is recommend that
you maintain a clearance of at least 6 inches (15.4 cm) in the front and back of the router
enclosure at all times.
If airflow through the router is blocked or restricted, or if the ambient air being drawn into
the router is too warm, an overtemperature condition within the router can occur. Under
extreme conditions, the router’s environmental monitoring (MBus) system shuts down
system power to protect internal electronic components from thermal damage.
The site should be as dust-free as possible. Dust tends to clog the air filter, reducing the flow
of cooling air through the system and increasing the risk of an overtemperature condition.