Determining active module

Both management modules run selftest routines to determine which module becomes the active management module and which becomes the standby management module. The module that was last active in the chassis is given precedence and becomes the "active" module. This module is the one that is booted going forward. If a module fails selftest and is unable to communicate with the other module, it does not take control as the management module. The other management module takes control and becomes the active module.

If both modules fail selftest, the fault LED flashes and neither module is operational.


You are not allowed to switchover to a management module that is not in standby mode. The module must have passed selftest and be in standby mode.

The entire boot decision process works as follows:

  1. If there is only one management module, that is the active management module.

  2. If one module is already booted and operational, a newly inserted module or the other management module booting always becomes the standby module. The standby module does not become active unless a switchover occurs.

  3. If there are two management modules and one fails selftest, the one that passes selftest becomes the active management module.

  4. If only one of two modules was ever booted in the chassis, that module is given precedence.

  5. The module that was active on the last boot becomes the active management module. This guarantees that the active module has the latest configuration data.

  6. If both management modules have previously booted in this chassis and were "active" the last time booted, the module that booted most recently becomes the active management module.

  7. If none of the above conditions are applicable, the module in the lowest slot becomes the active management module.