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Catalyst 3750 SwitchSoftware Configuration Guide
OL-8550-09
Chapter5 Managing Switch Stacks
Understanding Stacks
If you add a provisioned switch that is a different type than specified in the provisioned configuration to
a powered-down switch stack and then apply power, the switch stack rejects the (now incorrect) switch
stack-member-number provision type global configuration command in the startup configuration file.
However, during stack initialization, the nondefault interface configuration information in the startup
configuration file for the provisioned interfaces (potentially of the wrong type) are executed. Depending
on how different the actual switch type is from the previously provisioned switch type, some commands
are rejected, and some commands are accepted.
For example, suppose the switch stack is provisioned for a 48-port switch with Power over Ethernet
(PoE), the configuration is saved, and the stack is powered down. Then, a 24-port switch without PoE
support is connected to the switch stack, and the stack is powered up. In this situation, the configuration
for ports 25 through 48 is rejected, and error messages appear on the stack master switch console during
initialization. In addition, any configured PoE-related commands that are valid only on PoE-capable
interfaces are rejected, even for ports 1 through 24.
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 its 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 page5-22.

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 page5-8.

Effects of Removing a Provisioned Switch from a Stack

If a switch stack is running Cisco IOS Release 12.2(20)SE or later and you remove a provisioned switch
from the switch stack, the configuration 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.
Hardware Compatibility and SDM Mismatch Mode in Switch Stacks
The Catalyst 3750-12S switch supports desktop and aggregator Switch Database Management (SDM)
templates. All other Catalyst 3750 switches support only the desktop SDM templates.
The stack member number of
the provisioned switch is not
found in the provisioned
configuration.
The switch stack applies the default
configuration to the provisioned switch
and adds it to the stack.
Table5-1 Results of Comparing the Provisioned Configuration with the Provisioned Switch (continued)
Scenario Result