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RE-S-2000 Routing Engine Description
RE-S-2000 Routing Engine Components
Figure 1 shows the Routing Engine 2000.
Figure 1: Routing Engine 2000
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..
- DRAM—Provides storage for the routing and forwarding tables and for other Routing Engine processes.
- USB port—Provides a removable media interface through which you can install the Junos OS manually. Junos OS supports USB version 1.0.
- CompactFlash card—Provides primary storage for software images, configuration files, and microcode. The CompactFlash card is fixed and is inaccessible from outside the router.
- Hard drive—Provides secondary storage for log files, memory dumps, and rebooting the system if the CompactFlash card fails.
- Interface ports—The AUX, CONSOLE, and ETHERNET provide access to management devices. 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.
- Online/Offline button—Takes the Routing Engine online or offline when pressed.
- Extractor clips—Used for inserting and extracting the Routing Engine.
- Captive screws—Secure the Routing Engine in place.
 | Note: For specific information about Routing Engine components (for example, the amount of DRAM), issue the show chassis routing-engine command. |
Routing Engine Boot Sequence
The router is shipped with the Junos OS preinstalled on the Routing Engine. There are three copies of software:
- One copy on the CompactFlash card in the Routing Engine.
- One copy on the hard disk in the Routing Engine.
- One copy on a USB flash drive that can be inserted into the slot on the Routing Engine faceplate.
The Routing Engine boots from the storage media in this order: the USB device (if present), then the CompactFlash card, then the hard disk, then the LAN. Normally, the router boots from the copy of the software on the CompactFlash card.
