The cooling system components work together to keep all router components within the acceptable temperature range. The router has four fan trays, two trays located at the top, and two trays located at the bottom of the router that install horizontally. Each fan tray contains six fans. The fan trays are interchangeable and are hot-insertable and hot-removable.
The MX2020 router provides a two-stage front-to-back cooling system. Air is pushed into the bottom inlet and up through the lower fan tray, and exits through the opening between the backplanes in the center of the chassis. This cools the bottom MPCs, half of the SFBs and CB-REs. Air is pulled through the SFBs and all the CB-REs in the center of the chassis and is exhausted out the upper rear of the system. The CB-REs and SFBs are equipped with an air divider to deflect the exhaust air from the bottom half of the system out and direct the air to the top half MPCs.