SRX5800 Services Gateway Component Redundancy

The following major hardware components are redundant:

• Switch Control Boards (SCBs)—The host subsystem consists of a Routing Engine installed in an SCB. The device must have one host subsystem installed. You can install a second SCB for increased throughput, and a third SCB for redundancy. If a second or third SCB is installed, the host subsystem SCB functions as the master and the others function as the backup. If the SCB of the host subsystem fails, one of the other SCBs takes over as the master.
• Power supplies—In the AC configuration, a minimum of three power supplies are required to supply power to a fully configured services gateway. All AC power supplies share the load evenly. The addition of a fourth power supply provides full power redundancy. If one power supply fails in a redundant configuration, the three remaining power supplies provide full power.

  In the DC configuration, two power supplies are required to supply power to a fully configured services gateway. One power supply supports approximately half of the components in the services gateway, and the other power supply supports the remaining components. The addition of two power supplies provides full power redundancy. If one or two power supplies fail, the remaining power supplies can provide full power to the services gateway.

• Cooling system—The cooling system has redundant components, which are controlled by the host subsystem. If one of the fans fails, the host subsystem increases the speed of the remaining fans to provide sufficient cooling for the services gateway indefinitely.