M320 Router Routing Engine Redundancy
The M320 router has a redundant Routing Engine that is a component of the host subsystem (see Figure 196). The host subsystem consists of a Routing Engine and a Control Board. Two host subsystems can be installed in the M320 router. For more information about monitoring redundant Control Boards, see Monitoring Redundant Control Boards.
Both the Routing Engine and the Control Board must be installed for the host subsystem to function. When two host subsystems are installed in the router, both are powered on, but only one is the master; the second host subsystem is the backup and performs no functions. By default, the master host module has components installed in slots RE0 and CB0; the backup host module has components installed in slots RE1 and CB1. The Routing Engines are hot-pluggable.
The M320 router craft interface LEDs indicate the Routing Engine operating status and mastership. (See Check the M320 Router Routing Engine LEDs.)
