I've been reading through the documentation for our Catalyst 3750s an I wasn't quite satisfied with the info I got. Here's the deal: We have two stacks of 3750s, one with 5 switches, the other with 2. Right now I want to move one switch from the stack of 2 (which, I think, is the master switch, as denoted by the * in show version) and put it in the stack of 5. How can I do this without disrupting service to the network devices on the other switch in the stack of 2, or to the servers attached to the stack of 5?
been reading through the documentation for our Catalyst 3750s an I
wasn't quite satisfied with the info I got. Here's the deal: We have
two stacks of 3750s, one with 5 switches, the other with 2. Right now
I want to move one switch from the stack of 2 (which, I think, is the
master switch, as denoted by the * in show version) and put it in the
stack of 5. How can I do this without disrupting service to the
network devices on the other switch in the stack of 2, or to the
servers attached to the stack of 5?
Check out the below for creation and managment of stack in cisco 3750 switches
and If you want to add a new switch in stack as long as the new switch has the exact same IOS image as the existing stack, the stack will see the new switch. You don't need to power down. As long as you have two stacking cables connecting the first and second switches, removing one of them will not stop traffic. The third switch will adopt the same config as the original stack. You will just need to specify port settings.
Thanks for the info! I actually want to take one switch (the master switch, I believe) out of the stack of two. How will the stack of two deal with losing the master switch? Will it elect the last remaining switch to be the master and continue operating like normal, or will there be problems?
All the IOS images are 100% identical, btw, so there's no problem there.
I understand that you require instruction on how to add a new cat3750 to an existing stack.
First off, if a new switch needs to be added, it must have the same IOS image version as that of the existing 3750 in the stack. This avoids the version mismatch issue. To do so, the new switch to be added must already have the image loaded to it same as the ones on the stack.
This link has all necessary procedures when managing switch stacks:
One important note though, make sure the switches that you add to or remove from the switch stack are powered off.
This is because:
Adding powered-on switches (merging) causes the stack masters of the merging switch stacks to elect a stack master from among themselves. The re-elected stack master retains its role and configuration and so do its stack members. All remaining switches, including the former stack masters, reload and join the switch stack as stack members. They change their stack member numbers to the lowest available numbers and use the stack configuration of the re-elected stack master.
Removing powered-on stack members causes the switch stack to divide (partition) into two or more switch stacks, each with the same configuration. This can cause an IP address configuration conflict in your network. If you want the switch stacks to remain separate, change the IP address or addresses of the newly created switch stacks. If you did not intend to partition the switch stack:
a. Power off the new switch .
b. Reconnect them to the original switch stack through their StackWise ports.
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