Stacking two 3750 switches

Unanswered Question
Dec 1st, 2008

We have one 3750 in production and want to create a stack by adding a second 3750. The Cisco documentation that I have been able to find does not indicated whether this can be done without resetting the first switch that is already in production and would become the master.

We do not have a convenient maintenance window to create this stack, so my question is can we create this two member stack without having to reset the existing switch?

Also, what prep is required on the existing switch to have it become the master?

Here is some Cisco documentation that may be relevant to this issue from

To add a switch, as a slave, to a stack, complete these steps:

Note: Make sure the switch that you add into the stack has the same IOS version as the switches in the stack. Refer to Catalyst 3750 Software Upgrade in a Stack Configuration with Use of the Command-Line Interface to upgrade the IOS in a catalyst 3750 switch.

Change the switch priority of the switch to be added to "1".

switch stack-member-number priority new-priority-value

Note: This step is optional, but it will make sure that the switch has fewer chances to become a stackmaster in the future.

Power off the switch that is to be added.

Make sure that the stack is fully connected so that, when you connect the new switch, the stack will be at least in half connectivity and does not partition.

Connect the new switch to the stack with the StackWise ports.

Power on the newly added switch.

After the new switch comes up, issue the command show switch to verify stack membership.

Tips to Add a Switch as a Master to the Stack


I have this problem too.
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Giuseppe Larosa Mon, 12/01/2008 - 13:33

Hello Mark,

see the section

Add a Provisioned Switch to a Switch Stack

you need to configure the current switch as master.

Then you can use the info on the above mentioned section to prepare the addition of the second switch that has to satisfy the requirements about the IOS image and so on.

Using this procedure you should be able to add the second switch without impacts because you prepare the configuration on both the master and the future slave.

Hope to help



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