Juniper Networks MX480 - Manual (Page 51)

• 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, FPCs, and MPCs within the chassis through
the switch fabrics integrated into the SCB
The Routing Engine installs directly into a slot on the SCB (see Figure 14 on page 27 ).
Figure 14: SCB
SCB Slots
You can install one or two. The SCBs install horizontally into the front of the chassis in
the slots labeled
0 and 1 . If any slots are empty, you must install a blank panel.
SCB Redundancy
If two SCBs are installed, one SCB functions as the master SCB and the other as its
backup. If the master fails or is removed, the backup restarts and becomes the master.
SCB Components
Each SCB consists of the following components:
• Chassis management Ethernet switch
• I2C bus logic, used for low-level communication with each component
• Component redundancy circuitry
• Control Board/Routing Engine mastership mechanism
• Gigabit Ethernet switch that is connected to the embedded CPU complex on all
components
27 Copyright © 2013, Juniper Networks, Inc.
Chapter 2: MX480 Hardware Components