System Redundancy

The router is designed so that no single point of failure can cause the entire system to fail. The following hardware components contribute to system redundancy:

• Cooling system—The cooling subsystems have redundant components, which are controlled by the SSB. If a fan fails, the remaining fans provide sufficient cooling for the unit indefinitely. For more information, see Cooling System.
• Routing Engine—The router can have one or two Routing Engines. If two Routing Engines are installed, one (the master) is active and the other is in standby mode. If the master Routing Engine is removed from the chassis, the standby Routing Engine becomes active. For more information, see Routing Engine.
• Power supply—The router has two load-sharing, fully redundant power supplies to distribute either AC or DC power to the other components. If one power supply fails, the second power supply can provide full power to the router's components indefinitely. For more information, see Power System.
• System and Switch Board (SSB)—The router can have one or two SSBs. If two SSBs are installed, one is active and the other is in reset mode. If the active SSB is removed from the chassis, the other SSB becomes active. For more information, see System and Switch Board (SSB).

In the base configuration, the router has one Routing Engine and SSB, and multiple power supplies and cooling system components.