Cisco Stackwise

Thank you. This is helpful. We have not always specified a master switch and I was just wondering what ramifications there could be, if any. It seems that there really aren’t many. Let me ask you this, if there were a power outage and no master switch was set in the beginning (we just let it select one on its own) and a different master switch was selected after the power came back up, would there be any cons? It seems we always have issues after a power outage and I was just wondering if this could be the problem. To me it seems it would not since the configuration is pushed down to all the switches in the stack (if it is written to memory). Everyone swears they write to memory, but I also know this could be the issue if the changes weren’t saved. I am just wondering if we should make setting a master switch part of our best practices going forward, if that would alleviate some of our issues.

Hello Marlo

Yes indeed you’re right, in most cases it shouldn’t make a difference.

If you don’t specify a master switch, then the selection process is always the same (user priority, default config, hardware/software priority, uptime, MAC address). So unless something drastic happens, the same switch will be chosen as the master every time.

There is one exception here, however. In the lesson, you’ll notice that criterion number 4 is uptime. If at the time when the power comes back on, for some reason one switch powers on a couple of seconds before the other, then you may have a change in master/member roles. This is not very likely, but it is possible.

Now even if another master switch is selected, the overall operation of the stack should not be affected, assuming, as you say, that all switches still have their configs saved. So under normal operation, there should be no cons in the unlikely event that another switch is chosen as master.

Because there are so many situations in which “normal” operation is never the case, and because sometimes in networking there are so many variables involved when problems arise, it’s always best to limit the number of variables. For this reason, it wouldn’t hurt to assign a user priority to one of the switches to become master, just to ensure that the election process is not contributing to the problem you perceive whenever power goes out…

I hope this has been helpful!


Thank you very much. This answered my question and I have a much better understanding.

1 Like

1:10 says the default priority is 15, but It’s 1. can you please correct it in the text below.

Hello Abdulrahman

Yes, you are correct, the default priority value is indeed 1. I will let Rene know to make the necessary adjustments.



1 Like

Hello Laz,

What is precise difference of stack & VSD in cisco switches?
And where is stack configuration used mostly

Nitin Arora

Hello Nitin

Cisco Stackwise and Virtual Service Domain (VSD) are two completely different features. Stackwise allows you to create a single logical switch from multiple individual switches, while VSD is used to classify and separate traffic for network services, such as firewalls and traffic monitoring. For more info on VSD, take a look at the following documentation:

Are you sure you meant VSD? Maybe you meant VSS? If you meant VSS, then take a look at the following NetworkLessons note on various Switch high availability options for more details.

I hope this has been helpful!



I have a stack of 2 switches, and I need to add 2 more members.
What would be the steps?
The current stack of two switches will reboot when I add the other 2 ?
They are Cat 9200.

Thank you in advance.

Hello Alexis

Take a look at this Cisco documentation:

In it, it states that a stack of 9200 switches can have a stack member added by doing the following:

  1. Power off the new switch.
  2. Through their StackWise ports, connect the new switch to a powered-on switch stack.
  3. Power on the new switch.

In this process, you don’t have to turn off the active switches, they will continue to operate normally.

I hope this has been helpful!


bonjour monsieur Rene ;svp c’est quel logiciel donc vous utilisez pour la vitaulisation ?

Hello Berthol

I assume you mean which emulator is Rene using for the labs? In the past, it was Cisco VIRL that was used, but more recently he uses CML.

I hope this has been helpful!


1 Like