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Cisco Catalyst Blade Switch 3130 and 3032 for Dell Software Configuration Guide
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Chapter 5 Managing Switch Stacks
Configuring the Switch Stack
Enabling Persistent MAC Address
The switch stack MAC address is determined by the MAC address of the stack master. When a stack
master is removed from the stack and a new stack master takes over, the default is for the MAC address
of the new stack master to immediately become the new stack MAC router address. However, you can
enable the persistent MAC address feature to allow a time delay before the stack MAC address changes.
During this time period, if the previous stack master rejoins the stack, the stack continues to use its MAC
address as the stack MAC address, even if the switch is now a stack member and not a stack master. If
the previous stack master does not rejoin the stack during this period, the switch stack takes the MAC
address of the new stack master as the stack MAC address.You can also configure stack MAC persistency
so that the stack never switches to the MAC address of the new stack master.
Note
When you enter the command to configure this feature, a warning message appears containing the
consequences of your configuration. You should use this feature cautiously. Using the old stack master
MAC address elsewhere in the same domain could result in lost traffic.
You can configure the time period as 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. If the command is entered without a value, the time delay appears in the
running-config file with an explicit timer value of 4 minutes.
•
If you enter
0
, the stack MAC address of the previous stack master is used until you enter the
no
stack-mac persistent timer
command, which immediately changes the stack MAC address to that
of the current stack master. If you do not enter the
no stack-mac persistent timer
command, the
stack MAC address never changes.
•
If you enter a time delay of 1 to 60 minutes, the stack MAC address of the previous stack master is
used until the configured time period expires or until you enter the
no stack-mac persistent timer
command.
Note
If the entire switch stack reloads, it uses with the MAC address of the stack master as the stack MAC
address.