Juniper SRX5400 - Page 80

The host subsystem is composed of a Roung Engine installed directly into a slot on the faceplate of the
SCB. When there is no Roung Engine is a SCB, its slot must be covered with a blank panel.
Figure 38: Switch Control Board SRX5K-SCB
Each SCB consists of the following components:
• Chassis management Ethernet switch.
• I2C bus logic, used for low-level communicaon 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 funcons for the IOCs.
• Control FPGA—Provides the Peripheral Component Interconnect (PCI) interface to the Roung
Engine.
• 1000Base-T Ethernet controller—Provides a 1-Gbps Ethernet link between the Roung Engines.
• Ethernet switch—Provides 1-Gbps link speeds between the Roung Engine and the IOCs.
• Circuits for chassis management and control.
• Power circuits for the Roung Engine and SCB.
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