Spanning Tree Problems with Access Points connected to Procurve Switches

[simon_eng]

Anyone ever find switchports flapping on an off when Spanning Tree is active and an access point (7055, 7363, 7372, 7962) is connected? We have found this in several properties now with very similar configurations but have not been able to determine a cause. All of our hotels use Procurve switches at the edge (2910al-PoE or 2520-8G-PoE), all participate in spanning tree, but we only observe the flapping on about 1% of switchports. Of course, 1% for us means that 10-50 guests are getting knocked off the network regularly, so it is a bit of an issue (some ports have 200-300 state transitions *per day*.

We have verified that the configurations on the ports that have the problem match the ports that do not with regard to BPDU filtering, root-guard, etc. We do not believe that it is a deliberate attack because it is the same access points that have chronic issues, whereas the other 99% never do.

Any ideas?

[keith_redfield]

@mmulcahy - that's great insight. Did you individually remove mesh from each AP? Or a factory reset and reconfigure? (which is the "official" method)

[mike_mulcahy_59]

I did it individually. I didn't want to risk anything going wrong using my backup configs. not the most fun thing to do, but if I ever do need to mesh something, I would be able to do it on an individual AP basis.

[simon_eng]

Mike, That's a good idea for us to run down since we do seem to experience the issue only at sites that have mesh enabled. Oddly though, if memory serves, none of the affected APs were (or should have been) actively participating in the mesh, but we will certainly give that more attention now.

[steve_byrum_508]

IT's a good practice to not have mesh enabled on APs that are connected via the wire. I would suggest you set any AP that is not intended to be a mesh AP to ROOT only mode or if you are running newer versions of code you can disable mesh on a per AP basis.

When a wired AP goes into mesh mode the uplink switch may suspect a loop. Ruckus has a mechanism to avoid the switches detecting the loop. but it is not 100% guaranteed.

THe problem is if the wired connection is flaky it will cause the AP to thrash between wired and mesh and that thrashing can lead to a loop being detected or a real loop. Even more so when spanning tree kicks in there now is a third factor in the flapping as spanning tree can cause the wired port to become blocked sending the AP back to mesh status.

My recommendations are to disable mesh or set root mode on wired APs that do not require mesh. I

[koos_boersma]

Gents,

question. What happens when a AP connected to a wire is losing its wired connection. We setup the network with the Mesh function in our head as a fallback scenario. But if we disable Mesh for this wired AP's we are losing the fallback.

Suggestions?