M40 Router Cooling System
The M40 router cooling system consists of the following components:
- Air intake vent and air filter (see Figure 111)—Provide an opening for room air to enter the router. They are located at the bottom of the chassis front, below the craft interface. The air filter prevents dust and other particles from entering the cooling system. For replacement instructions, see the M40 router hardware guide.
- Upper and lower impeller assemblies (see Figure 110)—Cool the Packet Forwarding Engine components (backplane, SCB, FPCs, and PICs). The lower impeller assembly is located behind the craft interface at the front the chassis, and the upper assembly is located above the fan tray at the rear of the chassis. Each assembly houses two impellers for redundancy. The assemblies are not interchangeable. For replacement instructions, see the M40 router hardware guide.
- Fan tray (see Figure 111)—Cools the Routing Engine and backplane. The tray houses three fans for redundancy and is located above the Routing Engine at the upper rear of the chassis. For replacement instructions, see "Maintain and Replace the Fan Tray" on page 155.
- Power supply integrated fan—Cools the power supply. It is not field-replaceable.
Figure 110 shows the M40 router cooling system impeller trays.
Figure 111 shows the M40 router air filter and fan tray.
The M40 router cooling system consists of separate subsystems (sets of fans and impellers) that draw room air into the chassis to keep its internal temperature below a maximum acceptable level. After entering the chassis, the air stream separates into separate flows for the front and rear subsystems, and the temperature of each flow is monitored independently. Figure 112 shows the M40 router cooling system airflow.
