hh3cStackMacPersistence
1.3.6.1.4.1.25506.2.91.1.5
The mode of bridge MAC address persistence. When a stack starts,
the bridge MAC address of the master is used as that of the stack.
When the master leaves the stack, the bridge MAC address of the
stack changes depending on the mode of bridge MAC address persistence.
notPersist: The bridge MAC address of the new master is used
as that of the stack immediately.
persistForSixMin: The original bridge MAC address will be reserved for six
minutes. In this period, if the master that has left rejoins the stack,
the bridge MAC address of the stack will not change.
If the old master does not rejoin the stack within this period, the
bridge MAC address of the new master will be used as that of the stack.
persistForever: Whether the master leaves or not, the bridge MAC address
of the stack will never change.