Switch Control Board

The Switch Control Board (SCB) provides the following functions:

• Powers on and powers off IOCs and SPCs
• Controls clocking, system resets, and booting
• Monitors and controls system functions, including fan speed, board power status, PDM status and control, and the system front panel
• Provides interconnections to all the IOCs within the chassis through the switch fabrics integrated into the SCB

When the SCB is part of a host subsystem, the Routing Engine installs directly into a slot on the SCB (see Figure 1).

Figure 1: SCB

SCB Slots

You must install at least one SCB in the services gateway as part of a host subsystem.

The SCBs install into the front of the chassis in the slots labeled 0 and 1 on an SRX 5600 services gateway and 0, 1, and 2/6 on an SRX 5800 services gateway. If any slots are empty, you must install a blank panel.

SCB Redundancy

If two SCBs are installed in an SRX 5600 services gateway, one SCB functions as the master SCB and the other as its backup. If the master fails or is removed, the backup becomes the master.

On SRX 5800 services gateways, SCBs installed in slots 0 and 1 provide nonredundant fabric connections. A third installed SCB in slot 2/6 provides fabric redundancy but no additional control or routing functions.

Table 1: SCB Slot Mapping and Functionality

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.
• Switch fabric—Provides the switching functions for the I/O cards (IOC)s.
• Control FPGA—Provides the Peripheral Component Interconnect (PCI) interface to the Routing Engine.
• 1000Base-T Ethernet controller—Provides a 1-Gbps Ethernet link between the Routing Engines.
• Ethernet switch—Provides 1-Gbps link speeds between the Routing Engine and the IOCs.
• Circuits for chassis management and control.
• Power circuits for the Routing Engine and SCB.
• LEDs—Provide status (see SCB LEDs).

SCB LEDs

Three LEDs on the SCB indicate the status of the SCB. The LEDs, labeled FABRIC ACTIVE, FABRIC ONLY, and OK/FAIL, are located directly on the SCB. Table 2 describes the functions of the SCB LEDs.

Table 2: Switch Control Board LEDs