Routing Engine

The Routing Engine is an Intel-based PCI platform that runs JUNOS Internet software. Software processes that run on the Routing Engine maintain the routing tables, manage the routing protocols used on the router, control the router's interfaces, control some chassis components, and provide the interface for system management and user access to the router.

The Routing Engine installs into the rear of the chassis, in a compartment behind the card cage (see Figure 2). For information about the routing architecture, see System Architecture Overview.

The Routing Engine is hot-pluggable, as described in Field-Replaceable Units (FRUs). For replacement instructions, see Maintain and Replace Routing Engine Components.

Routing Engine Components

The Routing Engine (shown in Figure 6) is a two-board system with the following components:

• CPU—Runs JUNOS Internet software to maintain the router's routing tables and routing protocols. It has a Pentium-class processor.
• SDRAM—Provides storage for the routing and forwarding tables and for other Routing Engine processes.
• Compact flash drive—Provides primary storage for software images, configuration files, and microcode. The drive is fixed and inaccessible from outside the router.
• Hard drive—Provides secondary storage for log files, memory dumps, and rebooting the system if the flash drive fails.
• PC card slot—Accepts a removable PC card, which stores software images for system upgrades.
• Interfaces for out-of-band management access—Provide information about Routing Engine status to devices (console, laptop, or terminal server) that can be attached to access ports located on the craft interface.
• EEPROM—Stores the serial number of the Routing Engine.
• LED—Indicates disk activity for the internal IDE interface. It does not necessarily indicate routing-related activity.

The LEDs that report Routing Engine status are on the craft interface rather than the Routing Engine faceplate. See Routing Engine LEDs and Interface Ports.

• Reset button—Reboots the Routing Engine when pressed.
• Extractor clips—Control the locking system that secures the Routing Engine in the chassis.
  
  

  The appearance and position of electronic components or the PC card slot on your Routing Engine might differ from the figures in this section. These differences do not affect Routing Engine installation and removal or functionality.

  
       
  
  

  For specific information about components in a Routing Engine (for example, the capacity of the hard disk), issue the show chassis routing-engine command.

  
   
  
  

  Although the Routing Engine has a PC card slot, it is disabled on the M40 router. The router instead uses an LS-120 disk.

  
  

Figure 6: Routing Engine