Switch Stack Bridge Id And Router Mac Address; Stack Member Numbers - Cisco 3750G - Catalyst Integrated Wireless LAN Controller Configuration Manual

Understanding Switch Stacks

Switch Stack Bridge ID and Router MAC Address

The bridge ID and router MAC address identify the switch stack in the network. When the switch stack
initializes, the MAC address of the stack master determines the bridge ID and router MAC address.
If the stack master changes, the MAC address of the new stack master determines the new bridge ID and
router MAC address. However, when the persistent MAC address feature is enabled, there is an
approximate 4-minute 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. See
information.

Stack Member Numbers

The stack member number (1 to 9) identifies each member in the switch stack. The member number also
determines the interface-level configuration that a stack member uses. You can display the stack member
number by using the show switch user EXEC command.
A new, out-of-the-box switch (one that has not joined a switch stack or has not been manually assigned
a stack member number) ships with a default stack member number of 1. When it joins a switch stack,
its default stack member number changes to the lowest available member number in the stack.
Stack members in the same switch stack cannot have the same stack member number. Every stack
member, including a standalone switch, retains its member number until you manually change the
number or unless the number is already being used by another member in the stack.
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Catalyst 3750 Switch Software Configuration Guide
5-6
If you manually change the stack member number by using the switch
current-stack-member-number renumber new-stack-member-number global configuration
command, the new number goes into effect after that stack member resets (or after you use the
reload slot stack-member-number privileged EXEC command) and only if that number is not
already assigned to any other members in the stack. For more information, see the
Stack Member Number" section on page
by changing the SWITCH_NUMBER environment variable, as explained in the
Environment Variables" section on page
If the number is being used by another member in the stack, the switch selects the lowest available
number in the stack.
If you manually change the number of a stack member and no interface-level configuration is
associated with that new member number, that stack member resets to its default configuration. For
more information about stack member numbers and configurations, see the
Configuration Files" section on page
You cannot use the switch current-stack-member-number renumber new-stack-member-number
global configuration command on a provisioned switch. If you do, the command is rejected.
If you move a stack member to a different switch stack, the stack member retains its number only if
the number is not being used by another member in the stack. If it is being used by another member
in the stack, the switch selects the lowest available number in the stack.
If you merge switch stacks, the switches that join the switch stack of a new stack master select the
the lowest available numbers in the stack. For more information about merging switch stacks, see
the "Switch Stack Membership" section on page
Enabling Persistent MAC Address, page 5-19
5-22. Another way to change the stack member number is
3-15.
5-14.
5-3.
Chapter 5 Managing Switch Stacks
for more
"Assigning a
"Controlling
"Switch Stack
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