Host Subsystem; Switch Control Board (Scb) - Juniper MX240 Hardware Manual

Table 8: 40-Port Gigabit Ethernet DPC LEDs (continued)
Two LEDs, located on the craft interface above the DPC, display the status of the
DPC and are labeled
on the craft interface, see "DPC LEDs" on page 20.

Host Subsystem

The host subsystem provides the routing and system management functions of the
router. You can install one or two host subsystems on the router. Each host subsystem
functions as a unit; the Routing Engine must be installed directly into the Switch
Control Board.
NOTE: We recommend that you install two host subsystems for redundant protection.
If you install only one host subsystem, we recommend that you install it in slot
Each host subsystem has three LEDs that display its status. The host subsystem LEDs
are located on the upper left of the craft interface. For more information about the
host subsystem LEDs, see "Host Subsystem LEDs" on page 19.
The host subsystem consists of the following components:

Switch Control Board (SCB)

The Switch Control Board (SCB) provides the following functions:
The Routing Engine installs directly into a slot on the SCB (see Figure 8 on page 12).
Label Color State
Green On steadily
LINK
Off
OK and
Switch Control Board (SCB) on page 11
Routing Engine on page 14
Powers on and powers off DPCs
Controls clocking, system resets and booting
Monitors and controls system functions, including fan speed, board power status,
PDM status and control, and the craft interface
Provides interconnections to all the DPCs within the chassis through the switch
fabrics integrated into the SCB
Description
Link is active.
No link.
FAIL . For more information about the DPC LEDs located
Chapter 2: Hardware Components
0 .
11
Host Subsystem