RSTP - Problem adding new vlan

[JulienDono]

Hello my saviors,

I am trying to debbug a problem that is occuring on my network. Currently, we are running RSTP on the network because of some loops we have.

We currently have 129 vlans :

The problem is that, when we try to add a new vlan, the following message is shown : 

So my question is : As we are running RSTP, is there really an impact to this message ? Because RSTP is not running instance per vlan (like PVST can do), so is there really a problem with the STP configuration ?

Here is some other screenshots that might help diagnose the problem :

Thank you !

[David Ruess]

Hello,

I believe that is not quite accurate. RSTP DOES run a VLAN instance per VLAN and it does have a limit. Looks like you have reached it.

You could look at consolidating or you could migrate to MST which groups similar VLAN paths into 1 Spanning-tree instance. If you have over 128 like your message states I feel like that's a good indicator to look at other options.

RSTP is a bit faster with its timers and has some different port states, but that's pretty much it.

Hope that helps

-David

[JulienDono]

Hello David, thank you for your answer. As it has been pointed out by @MHM Cisco World and @Reza Sharifi, I am actually running R-PVST, when the information I was given was RSTP ... I did not take a good look into it.

Thanks

[MHM Cisco World]

sorry but you dont run RSTP you run R-PVST,
it shown in summary.
so your sw is limit to 128 instance.

[JulienDono]

Hey, thank you, I don't know why I had this information it was RSTP, where it cleary shows R-PVST, I should open my eyes a bit more.

Thanks again.

[Reza Sharifi]

Hi,

The limitations apply to the following protocols:

PVST, PVST+ or Rapid-PVST.

And per the first screenshot you posted, you are running Rapid-PVST.

HTH

[JulienDono]

Thank you for pointing it out, like @MHM Cisco World did, I really should open my eyes more.

[Reza Sharifi]

No worries. The outputs sometimes can get confusing. Also, I would look and see if you really need 128 vlans configured per switch. In reality, sometimes you may for example be using 50 or 60 vlans but there are 128 or 129 configured. So, delete what is not needed.

HTH

[JulienDono]

So, in my case, there is no reason to be in R-PVST, is there any difficulties in switching back to RSTP ?

Thanks again

[Reza Sharifi]

You can switch to RSTP, but I would make a plan, document it, and study it before implementing it in a maintenance window.

HTH