Managing OmniSwitch 6855 Series Stacks
Roles Within the Stack
OmniSwitch 6855 Series Hardware Users Guide
September 2011
page 7-5
Important Note.
For management module redundancy to work effectively, the software on all switches
operating in the stack must be synchronized at all times. Refer to
“Synchronizing Switches in a Stack” on
page 7-37
for more information.
Redundant Management Module Failover (Three or More Switches)
Secondary
Primary
Idle
Idle
Secondary
Offline
Idle
Idle
Primary
Offline
Secondary
Idle
!
Primary
Idle
Secondary
Idle
A stack of four OmniSwitches is operating normally.
The stack consists of a primary module, secondary
module, and two elements operating in idle status. (The
software on all elements in the stack is synchronized.)
The primary management module in the stack fails or is
taken offline (e.g., powered off or rebooted by the user).
The switch operating as the secondary management module
immediately takes over the primary role. Meanwhile, the
adjacent switch—previously operating in idle status—now
assumes the secondary management role.
If the switch that failed or was taken offline comes back
online, it will assume an idle role in the stack. In other
words, it will act essentially as an NI module in the virtual
chassis, passing traffic via its Ethernet.
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