NOTE:
If two Routing Engines are installed, they must both be the same
hardware model.
There is a USB memory device that connects directly into the front of Routing Engine.
The USB port allows you to plug in a USB keychain device.
Figure 10: M120 Routing Engine
•
Routing Engine Components on page 19
•
Routing Engine Boot Sequence on page 20
Routing Engine Components
Each Routing Engine (shown in Figure 10 on page 19) 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.
•
USB port—Provides a removable media interface through which you can install the
Junos OS manually. See Figure 11 on page 20. Junos supports USB version 1.0.
•
CompactFlash card—Provides primary storage for software images, configuration files,
and microcode. The disk is a fixed compact flash and 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.
•
LED—Indicates disk activity for the internal IDE interface. It does not necessarily indicate
routing-related activity.
NOTE:
The LEDs that report host module status (including Routing Engine
status) are on the craft interface rather than the Routing Engine faceplate.
•
HDD LED—Indicates disk activity for the hard disk drive.
19
Copyright © 2010, Juniper Networks, Inc.
Chapter 2: M120 Hardware Components
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