Alcatel OS6855-24 User Guide - Page 154

Roles Within the Stack Managing OmniSwitch 6855 Series Stacks Primary Secondary 1 A stack of two OmniSwitches is operating normally. The stack consists of a primary module and a secondary module. (The software on both elements in the stack is synchronized.) ! Offline Secondary Offline Primary 2 The primary management module fails or is taken offline (e.g., powered off or rebooted by the user). 3 The switch operating as the secondary management module immediately takes over the primary role. It is at this point essentially operating as a stand-alone switch. Secondary Primary 4 If the switch that previously failed or was taken offline comes back online, it will assume the secondary role in the stack. Redundant Management Module Failover (Two Switches) page 7-6 OmniSwitch 6855 Series Hardware Users Guide September 2011