I have noticed on a few different occasions that the VLAN ID under VLAN mappings on our APs is changing for some reason when an AP loses connectivity to its primary controller and then reassociates. For instance, at one particular site we have several APs that have their native VLAN set to 97. Then under the VLAN mappings on the AP we have a VLAN 20 ID for our production wireless and a VLAN 998 ID for our guest wireless. When any of these APs lose connectivity to the controller and then reassociates the VLAN ID for guest changes to 99. But VLAN ID 20 does not change. 99 is the VLAN identifier for our controller management interface. All of these APs are running in HREAP local switching mode. Any insight on why the VLAN ID changes would be appreciated.
There are a couple major differences for the primary and secondary controllers. First, the management VLAN identifier on the management interface is a different number on each of the controllers. The primary controller is 99 where as the secondary is 97. Second, the primary controller guest WLAN is using HREAP local switching. The secondary controller guest WLAN is using local mode.