Stack-Mac Persistent Timer - Cisco Catalyst 3650 series Command Reference Manual

stack-mac persistent timer

To enable the persistent MAC address feature, use the stack-mac persistent timer command in global
configuration mode on the switch stack or on a standalone switch. To disable the persistent MAC address
feature, use the no form of this command.
stack-mac persistent timer [0| time-value]
no stack-mac persistent timer
Syntax Description
0
time-value
Command Default
Persistent MAC address is disabled. The MAC address of the stack is always that of the first active switch.
Command Modes
Global configuration
Command History
Release
Cisco IOS XE 3.3SECisco IOS XE 3.3SE
Usage Guidelines
By default, the stack MAC address will always be the MAC address of the first active switch, even if a new
active switch takes over. The same behavior occurs when you enter the stack-mac persistent timer command
or the stack-mac persistent timer 0 command.
When you enter the stack-mac persistent timer command with a time-value, the stack MAC address will
change to that of the new active switch after the period of time that you entered whenever a new switch
becomes the active switch. If the previous active switch rejoins the stack during that time period, the stack
retains its MAC address for as long as the switch that has that MAC address is in the stack.
If the whole stack reloads the MAC address of the active switch is the stack MAC address.
Note If you do not change the stack MAC address, Layer 3 interface flapping does not occur. This also means
that a foreign MAC address (a MAC address that does not belong to any of the switches in the stack) could
be the stack MAC address. If the switch with this foreign MAC address joins another stack as the active
switch, two stacks will have the same stack MAC address. You must use the stack-mac update force
command to resolve the conflict.
(Optional) Continues using the MAC address of the current active switch indefinitely,
even after a new active switch takes over.
(Optional) Time period in minutes before the stack MAC address changes to that of
the new active switch. The range is 1 to 60 minutes.
Command Reference, Cisco IOS XE Everest 16.5.1a (Catalyst 3650 Switches)
stack-mac persistent timer
Modification
This command was introduced.
875