Alcatel-Lucent OmniSwitch 6850E Series Hardware User's Manual page 133

Managing OmniSwitch 6850E Series Stacks
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
page 6-37 for more information.
Primary
Secondary
Idle
Idle
!
Offline
Secondary
Idle
Idle
Offline
Primary
Secondary
Idle
Idle
Primary
Secondary
Idle
Redundant Management Module Failover (Three or More Switches)
OmniSwitch 6850E Series Hardware Users Guide
"Synchronizing Switches in a Stack" on
1
A stack of four switches 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.)
2
The primary management module in the stack 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. Meanwhile, the
adjacent switch—previously operating in idle status—now
assumes the secondary management role.
4
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.
January 2013
Roles Within the Stack
page 6-5