Specifications
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§ Front Cooling Subsystem—An upper impeller and a lower fan tray cool
the FPCs, the PICs and the midplane.
§ Rear Cooling Subsystem—A pair of impellers cools the SFMs, the host
module, the PCGs, and the power supplies.
The MCS monitors the temperature of the router’s components. When the router
is operating normally, the impellers and fans function at lower than full speed. If
an impeller or fan fails or is removed, the temperature increases and the speed of
the remaining impellers and fans is automatically adjusted to keep the
temperature within the acceptable range.
The air intake for both cooling subsystems is located on the front of the chassis,
below the FPC card cage. An air filter in front of the air intake prevents dust and
other particles from entering the cooling system.
Front Cooling Subsystem
The front cooling subsystem comprises a large, central impeller that is located
above the FPC card cage and a fan tray located below the FPC card cage.
Together, they cool the FPCs and PICs.
The front impeller and fan tray are both hot-insertable and hot-removable.
Rear Cooling Subsystem
The rear cooling subsystem comprises a pair of impellers that are located at the
upper right and lower left of the rear of the chassis. Together, they cool the
SFMs, Routing Engine, MCS, and PCGs.
Each rear impeller is hot-insertable and hot-removable. The upper and lower
impellers are not interchangeable. The power supplies are cooled by air drawn
through the chassis by the cooling system.
Air Filter
The air filter, located at the front of the air intake, prevents dust and other
particles from entering the cooling system. Behind the air filter is a non-removable
air intake cover which provides EMI shielding.