Platform Support

The following platforms support redundant Routing Engines:

• M10i router—Each High-Availability Chassis Manager (HCM) and Routing Engine function as a unit. Keepalive messages are sent between Routing Engines over the interconnected HCM switches.
• M20 router—A single System and Switch Board (SSB) communicates with the Routing Engines. Keepalive messages are sent between the master and backup Routing Engine through the switch on the SSB. In this way, the master and the backup Routing Engines exchange state information.
• M40e and M160 routers—Each Miscellaneous Control Subsystem (MCS) and Routing Engine function as a unit, or host module. Keepalive messages are sent from one Routing Engine to the other over the fpx2 interface across the Peripheral Component Interconnect (PCI) bridge. The keepalive message is received by the other host module on the fpx1 interface. A keepalive response is sent back over the fpx2 interface to the other Routing Engine.
• M120, M320, and T320 routers and T640 and T1600 routing nodes—Each Routing Engine and Control Board (CB) function as a unit, or host subsystem. Keepalive messages are sent from the Routing Engine over the em0 interface. The keepalive message is forwarded to the other host subsystem over the bcm0 interface on the Control Board. A keepalive response is sent back over the em0 interface to the other Routing Engine.
• MX–series Ethernet Services routers—Each Routing Engine and Switch Control Board (SCB) function as a unit, or host subsystem. Keepalive messages are sent between Routing Engines over either the em0 interface or the em1 interface.