Understanding Redundant HCMs
Purpose
You monitor and maintain HCMs on the M10i router so that they can monitor and control router components, control component power-up and power-down, signal which Routing Engine is master, display alarm conditions, and take PICs offline.
What Are Redundant HCMs
Two HCMs are installed in an M10i router. Each HCM works with a companion Routing Engine.
Two HCMs are installed into the midplane from the front of the chassis, as shown in Figure 234. The master HCM performs all functions and provides PIC removal buttons for the first Flexible PIC Concentrator (FPC). The standby HCM provides PIC removal buttons for the second FPC. The HCM in the slot labeled HCM0 is paired with the Routing Engine in the slot labeled RE0. Likewise, the HCM in the slot labeled HCM1 is paired with the Routing Engine in the slot labeled RE1. By default, the HCM in the slot labeled HCM0 is the master.
When HCM mastership changes because of failure, Routing Engine mastership also changes.