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Catalyst 2960 and 2960-S Switch Software Configuration Guide
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Chapter 7 Managing Switch Stacks
Understanding Stacks
Note If the switch stack does not contain a provisioned configuration for a new switch, the switch joins the
stack with the default interface configuration. The switch stack then adds to i ts running configuration a
switch stack-member-number provision type global configuration command that matches the new
switch.
For configuration information, see the “Provisioning a New Member for a Stack” section on page 7-20.

Effects of Replacing a Provisioned Switch in a Stack

When a provisioned switch in a switch stack fails, is removed from the stack, and is replaced with
another switch, the stack applies either the provisioned configuration or the default configuration to it.
The events that occur when the switch stack compares the provisioned configuration with the
provisioned switch are the same as those described in the “Effects of Adding a Provisioned Switch to a
Stack” section on page 7-7.

Effects of Removing a Provisioned Switch from a Stack

If you remove a provisioned switch from the switch stack, the configurat ion associated with the removed
stack member remains in the running configuration as provisioned information. To completely remove
the configuration, use the no switch stack-member-number provision global configuration command.
Stack Software Compatibility Recommendations
All stack members must run the same Cisco IOS software version to ensure compatibility in the stack
protocol version among the members.
Stack Protocol Version Compatibility
The stack protocol version has a major version number and a minor version number (for example 1.4,
where 1 is the major version number and 4 is the minor version number).
Switches with the same Cisco IOS software version have the same stack protocol version. Al l features
function properly across the stack. These switches with the same software version as the master
immediately join the stack.
If an incompatibility exists, a system message describes the cause of the incompatibility on the specific
stack members. The master sends the message to all members.
For more information, see the “Major Version Number Incompatibility Among Switches” procedure on
page 7-9 and the “Minor Version Number Incompatibility Among Switches” procedure on page 7-10.
Major Version Number Incompatibility Among Switches
Switches with different Cisco IOS software versions likely have different stack protocol versions.
Switches with different major version numbers are incompatible and cannot exist in the same stack.