Chassis is a rigid sheet metal, which contains all other router components. Please refer to the typical router chassis below.
Flexible PIC Concentrators:
The FPCs contains the Physical interface Cards (PICs) used in the router and connect them to other router components. FPCs install into the front of the router in either a vertical or
horizontal orientation, depending on the router.
Physical Interface Cards:
PICs are used to connect to a network media. PICs receive incoming packets from the network and transmit outgoing packets to the network. PICs encapsulate
the packets received from the FPCs before transmitting them to the network.
The Routing Engine consists of an Intel-based PCI platform running the JUNOS software. The Routing Engine maintains the routing tables used by the router. Routing Engine consists of a
CPU; SDRAM for storage of the routing and forwarding tables and other processes; a compact flash disk for primary storage of software images, configuration
files, and microcode; a hard disk for secondary storage; a PC card slot (on some M40 routers, a floppy disk) for storage of software upgrades; and interfaces for
out-of-band management access.
Each Juniper Routers has one, two, or four load-sharing power supplies. The power supplies are connected to the router midplane (on an M40 router, to the router backplane), which distributes
the different output voltages throughout the router and its components. Some routers can operate using either AC or DC power while the other routers operate
with DC power only.
The cooling system keeps all router components within the recommended operating temperature limits. If one component of the cooling system fails or is removed, the system automatically adjusts the
speed of the remaining components to keep the temperature within the acceptable range. The cooling system for each router is unique and can consist of fans,
impellers, and air filters.