08-23-2012 11:05 PM
Has anyone seen anything bad when having STP enabled on the controllers on this code? We've seen an issue where the controller will be seen as the root port even if the vlan that it has terminates on it and it's not trunk beyond the controller.
08-24-2012 09:00 AM
If STP is enabled and the controller has a lower root bridge priority than existing switches on your network, it will become the root bridge, no matter the VLAN unless you are running PVST and this is configured the same way on your network side as well. Do you need to have STP enabled on the controller? If you don't general best practice is to disable it on the controller.
08-28-2012 03:09 PM
The controller doesn't have a lower priority and it's not becoming the root bridge. The controller's port is becoming the Root Port even though that vlan is not being trunk past the controller.
08-28-2012 11:24 PM
I have set up a test environment with an Aruba controller and two Cisco 3560 switches. One of the 3560 switches is setup as the root, but the controller is still saying that it's the root. All are running RSTP.
08-29-2012 12:03 AM
can you explain " even though that vlan is not being trunk past the controller. "
is the port working as trunk or access with specific vlan? -if I remmember, root port means that this port is the best port to reach the STP-root switch, which mean that the MC itself is not the STP-root switch, if it is then all the ports should be designated.
08-29-2012 05:48 AM
As long your controller is not becoming the ROOT bridge, then you are fine. It does not matter if you're trunking the VLAN or not or if it's an access port. STP is a layer2 protocol. You can configure PVST (per-VLAN STP) and control which ports on your switches are designated ports/etc but I doubt this is your environment. You are merely seeing which port the root bridge is reachable on.
My recommendation is that unless you require STP on the Aruba controller for blocking a loop, I would disable it. Or leave it as is as it does not mean you have an issue.
I would also recommend taking a look at the following for better understanding of STP and how it works.
09-01-2012 05:00 PM
The Cisco switch is setup as the Root Switch since it has a better priority, but the Aruba controller is still saying that it's the root bridge.
Does Aruba recommend disabling STP to this day?
09-04-2012 05:50 AM
You mentioned in an earlier post that the controller shows a root port instead of being a root bridge. These are 2 different things. Can you post the output of stp status on both the Aruba controller and your Cisco root bridge switch?
- show spanning-tree
- show spanning-tree interface
- show spanning-tree (I believe -- haven't done this in a while on Cisco).
With regards to recommendation, I usually disable STP on the Aruba controller if you do not have a need for it - i.e. you are not uplinking 2 ports from the controller (non-LACP/LAG/Aggregated) to your network.