M40e and M160 Router Routing Engine Redundancy
The M40e and M160 routers have redundant Routing Engines that are components of the host module (see Figure 195). The host module consists of a Routing Engine and a Miscellaneous Control Subsystem (MCS). You can install two host modules in the M40e and M160 routers. For more information about monitoring redundant MCSs, see Monitoring Redundant MCSs.
Both the Routing Engine and the MCS must be installed for the host module to function. When two host modules are installed in the router, both are powered on, but only one is the master; the second host module is the backup and performs no functions. By default, the master host module has components installed in slots RE0 and MCS0; the backup host module has components installed in slots RE1 and MCS1.
The M40e and M160 router craft interface LEDs indicate the Routing Engine operating status and mastership. (See Check the M40e and M160 Router Routing Engine LEDs.)
