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Catalyst 2960 and 2960-S Switch Software Configuration Guide
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Chapter 7 Managing Switch Stacks
Configuring the Switch Stack
Default Switch Stack Configuration
Table 7-3 shows the default switch stack configuration.
Enabling Persistent MAC Address
The MAC address of the master determines the stack MAC address. When a master is removed from the
stack and a new master takes over, the MAC address of the new master to become the new stack MAC
address. However, you can set the persistent MAC address feature with a time delay before the st ack
MAC address changes. During this time period, if the previous master rejoins the stack, the stack
continues to use that MAC address as the stack MAC address, even if the switch is now a member and
not a master. You can also configure stack MAC persistency so that the stack MAC address never
changes to the new master MAC address.
Caution When you configure this feature, a warning message displ ays the consequences of your configuration.
You should use this feature cautiously. Using the old master MAC address elsewhere in the domain could
result in lost traffic.
You can set the time period from 0 to 60 minutes.
• If you enter the command with no value, the default delay is 4 minutes. We recommend that you
always enter a value. The time delay appears in the configuration file with an explicit timer value of
4 minutes.
• If you enter 0, the stack MAC address of the previous master is used until you enter the no
stack-mac persistent timer global configuration command, which changes the stack MAC address
to that of the current master. If you do not enter this command, the stack MAC address does not
change.
• If you enter a time delay of 1 to 60 minutes, the stack MAC address of t he previous master is used
until the configured time period expires or until you enter the no stack-mac persistent timer
command.
If the previous master does not rejoin the stack during this period, the stack uses the MAC address of the
new master as the stack MAC address.
Note If the entire switch stack reloads, it acquires the MAC address of the master as the stack MAC address.
Table 7-3 Default Switch Stack Configuration
Feature Default Setting
Stack MAC address timer Disabled.
Member number 1
Member priority value 1
Offline configuration The switch stack is not provisioned.
Persistent MAC address Disabled.