M20 Router Cooling System
The M20 router cooling system consists of the following components (see Figure 108):
- Three front fan trays—Cool the Flexible PIC Concentrators (FPCs) and the System and Switch Boards (SSBs). The fan trays are located on the left front side of the chassis. Each tray houses three fans.
- Routing Engine fan tray—Cools the Routing Engines. The fan tray is located behind the Routing Engine panel. It houses two fans.
- Power supply integrated fan—Cools each power supply. It is built into the supply.
The cooling system includes several fan trays that draw room air into the chassis to keep its internal temperature below a maximum acceptable level. The cooling subsystems have redundant components, which are controlled by the SSB. If a fan fails, the remaining fans provide sufficient cooling for the unit indefinitely (see Figure 109.
