M40e System Redundancy

The M40e Multiservice Edge 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—When the temperature inside the router is below the acceptable maximum, the cooling system’s components function at less than full speed. If the temperature becomes excessive—for example, because a cooling system component is removed—the MCS automatically increases the speed of the remaining components to reduce the temperature. The cooling system can function at the higher speed indefinitely. For more information, see M40e Cooling System Description.
• FPC—Each FPC has two I/O Manager ASICs, one that interacts with the active SFM and the other in standby mode. If two SFMs are installed and the active one stops functioning, the standby I/O Manager ASIC automatically becomes active when the standby SFM boots and becomes the active SFM. For more information, see M40e Flexible PIC Concentrators (FPCs) Description.
• Host module (Routing Engine and MCS functioning together)—The router can have one or two host modules. If two host modules are installed, one (the master) is active and the other is in standby mode. If the master host module (or either of its components) is removed from the chassis, the standby host module becomes active. The Routing Engine and MCS must reside in adjacent slots and be fully operational for the host module to function. For more information, see M40e Host Module Description.
• PCG—The router has two PCGs. Both PCGs send their clock signals to the other Packet Forwarding Engine components, along with a signal that indicates which clock is the master. If one PCG fails, the other PCG becomes the master system clock. For more information, see M40e Packet Forwarding Engine Clock Generators (PCGs) Description.
• 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 M40e Power System Description.
• SFM—The router can have one or two SFMs. If two SFMs are installed, one is active and the other is in standby mode. If the active SFM fails or is removed from the chassis, the standby SFM automatically boots and becomes the active SFM. For more information, see M40e Switching and Forwarding Module (SFM) Description.

In the base configuration, the router has one host module and SFM, and multiple PCGs, power supplies, and cooling system components.