We have 2 WLCs that randomly becomes unreachable via ping resulting to the APs associating back and forth between the primary and secondary controllers(HA SKU) but somehow you can access their WEB GUI and cli and can even ping the core switch and there are no logs on both WLC that they went down. Tried transferring the connection and switching out the patch cords and even upgrading to TAC recommended firmware version but the issue still persists. TAC only changed Retransmit config parameters but it still didn't solve the issue. we also checked the switch they are connected to and there are no logs indicating that the port went down.
Here are the details of the device:
Wireless LAN Controller
Model No. .................................AIR-CT2504-K9
Product Version.................................. 8.5.161.11
Bootloader Version............................... 1.0.20
Field Recovery Image Version..................... 7.6.101.1
Firmware Version................................. PIC 20.0
Core Switch(Stacked)
Model Number : WS-C3850-24P
SW Version :16.6.6
*****EDITED*****
Here are some observations since i posted this topic
- The Primary WLC can reach its Gateway, Laptop and Secondary WLC but not the Access Points
- The Laptop is able to ping the Gateway of the Primary and but not the Primary WLC
- The Core Switch is able to reach the Primary WLC, Secondary WLC and Access Points
- The Access Point is able to reach the Gateway of the Primary, Secondary WLC but not the Primary WLC
Based on the behavior there is a possibility that the core switch is causing the issue or another device is blocking the traffic but there are no logs on the core switch or forescout of traffic being blocked and the core switch has no access list applied on the vlans of the AP and WLC.
