The Routing Engine (shown in Figure 10)
consists of the following components:
CPU—Runs JUNOS software to maintain the services gateway'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.
USB port—Provides a removable media
interface through which you can install the JUNOS software manually.
(See Figure 11.) JUNOS supports USB version
Internal flash disk—Provides primary storage for
software images, configuration files, and microcode. The disk is a
fixed compact flash and is inaccessible from outside the services gateway.
Hard disk—Provides secondary storage for log files,
memory dumps, and rebooting the system if the internal compact flash
HDD LED—Indicates disk activity for the hard disk
Management ports—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. The interface ports are labelled AUX, CONSOLE, and ETHERNET.
EEPROM—Stores the serial number of the Routing Engine.
Reset button—Reboots the Routing Engine when pressed.
Online/Offline button—Not supported in the current release.
Extractor clips—Used for inserting and extracting
the Routing Engine.
Captive screws—Secure the Routing Engine in place.
Figure 11: USB Memory Device in a Routing
The Routing Engine has four LEDs that indicate its status. The
LEDs, labeled MASTER, HDD, ONLINE, and FAIL, are located directly on the faceplate of the Routing Engine. Table 8 describes the functions of
the Routing Engine LEDs.