J2300 Routing Engine

The Routing Engine provides three main functions:

• Creates the packet forwarding switch fabric for the Services Router, providing route lookup, filtering, and switching on incoming data packets, then directing outbound packets to the appropriate interface for transmission to the network.
• Maintains the routing tables used by the router and controls the routing protocols that run on the router.
• Provides control and monitoring functions for the router, including controlling power and monitoring system status.

The Routing Engine consists of the following components:

• Processor—Creates the packet forwarding switch fabric for the router and runs JUNOS Internet software to maintain the router's routing tables and routing protocols.
• DRAM—Buffers incoming packets and provides storage for the routing and forwarding tables and for other Routing Engine processes.

  To view the amount of DRAM installed on your router, issue the show chassis routing-engine command.

• EPROM—Stores the serial number of the Routing Engine.

  To view the serial number of the Routing Engine, issue either the show chassis routing-engine command or the show chassis hardware command.

• Compact flash drive—Provides primary storage for software images, configuration files, and microcode. The primary compact flash drive is accessible from the rear of the router. For information about replacing the primary compact flash drive, see Removing and Installing the Primary Compact Flash Disk.

J2300 Boot Devices

The J2300 Services Router can boot from two devices:

• Primary compact flash disk
• USB storage device

Normally, the Services Router boots from the primary compact flash disk. If the compact flash disk fails, the router attempts to boot from the removable USB storage device, if present, which is the alternate boot device.