M320 Routing Engine 2000 Description

Each Routing Engine (shown in Figure 1) consists of the following components:

• CPU—Runs Junos OS to maintain the router's routing tables and routing protocols. It has a Pentium-class processor.
• DRAM—Provides storage for the routing and forwarding tables and for other Routing Engine processes.
• CompactFlash card—Provides primary storage for software images, configuration files, and microcode. The CompactFlash card is inaccessible from outside the router.
• Hard disk—Provides secondary storage for log files, memory dumps, and rebooting the system if the CompactFlash card fails.
• USB port—Provides a removable media interface through which you can install the Junos OS manually. The Junos OS supports USB version 1.0.
• LED—Indicates disk activity for the internal IDE interface. It does not necessarily indicate routing-related activity.
• 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 Connector Interface Panel (CIP).

  Each Routing Engine has one 10/100-Mbps Ethernet port for connecting to a management network, and two asynchronous serial ports—one for connecting to a console and one for connecting to a modem or other auxiliary device.

• EEPROM—Stores the serial number of the Routing Engine.
• Reset button—Reboots the Routing Engine when pressed.

Figure 1: Routing Engine 2000

On the RE-A-2000-4096 Routing Engine, the boot sequence for the storage media is as follows: USB device (if present), then the CompactFlash card (if present), then the hard disk.

The device from which the router boots is called the primary boot device, and the other device is the alternate boot device.

Note: If the router boots from an alternate boot device, a yellow alarm lights the LED on the router’s craft interface.