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Switch Control Board SRX5K-SCB Specifications

The SRX5K-SCB Switch Control Board (SCB) (Figure 31) performs the following functions:

  • Powers on and powers off I/O cards (IOCs) and Services Processing Cards (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

The SRX5400 Services Gateway supports only one SCB. The SRX5600 Services Gateway has one SCB installed and you can install a second SCB for redundancy. The SRX5800 Services Gateway has two SCBs installed and you can install a third SCB for switch fabric redundancy.

The host subsystem is composed of a Routing Engine installed directly into a slot on the faceplate of the SCB. When there is no Routing Engine is a SCB, its slot must be covered with a blank panel.

Figure 31: Switch Control Board SRX5K-SCB

Switch Control Board SRX5K-SCB

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.
  • Gigabit Ethernet switch that is connected to the embedded CPU complex on all components.
  • Switch fabric—Provides the switching functions for the IOCs.
  • 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.


  • SCB with slot for Routing Engine
  • Maximum throughput: 75 Gbps per slot

Software release

  • Junos OS Release 9.2 and later

Cables and connectors

Slot for Routing Engine



Supported Slots

  • SRX5400–Only bottom slot 0
  • SRX5600–Only bottom slots 0 and 1
  • SRX5800–Only center slots 0, 1, and 2/6

Power Requirement

150 W


Approximately 10 lb (4.5 kg)


OK/FAIL LED, one bicolor:

  • Green–The SCB is operating normally.
  • Red–The SCB has failed and is not operating normally.
  • Off–The SCB is powered down.


  • Green–The SCB is operating in fabric-only mode.
  • Off–The SCB is operating in fabric/control board mode.


  • Green–The fabric is in active mode.

Serial Number Location

The serial number label is located as shown in Figure 32.

Figure 32: SCB Serial Number Label

SCB Serial Number Label

Related Documentation

Modified: 2017-04-20