Back to All Scenarios
PASSEDnetwork / wlc_failure
WLC Failure — All Managed APs Orphaned
The Cisco 9800 Wireless LAN Controller crashes, orphaning 60 managed access points. APs enter standalone mode with limited functionality. New client authentications fail because RADIUS proxy is unavailable. Existing clients remain associated but cannot roam.
Pattern
WIRELESS_CONTROLLER
Severity
CRITICAL
Confidence
92%
Remediation
Remote Hands
Test Results
| Metric | Expected | Actual | Result |
|---|---|---|---|
| Pattern Recognition | WIRELESS_CONTROLLER | WIRELESS_CONTROLLER | |
| Severity Assessment | CRITICAL | CRITICAL | |
| Incident Correlation | Yes | 36 linked | |
| Cascade Escalation | Yes | Yes | |
| Remediation | — | Remote Hands — Corax contacts on-site support via call, email, or API |
Scenario Conditions
Cisco 9800-40 WLC. 60 Catalyst 9120AXI APs. FlexConnect mode not configured. Central switching/authentication. WLC crash due to memory leak in 17.9.4. No HA SSO pair. 800+ wireless clients.
Injected Error Messages (3)
Cisco 9800 WLC crashed — device unreachable, CAPWAP control plane down, 60 APs entering standalone mode, %WLAN-3-WLC_CRASH: memory leak in wncd process (17.9.4), core dump generated, HA SSO not configured, management interface unresponsive
RADIUS authentication proxy unavailable — WLC-mediated 802.1X authentication failing, ISE not receiving RADIUS requests from APs (proxy through WLC), new wireless client connections rejected, EAP timeout after 30 seconds
Wireless client roaming broken — 800+ clients cannot roam between APs after WLC failure, fast roaming (802.11r/k/v) unavailable without WLC, clients stuck on original AP, signal quality degrading as users move, throughput dropping
Neural Engine Root Cause Analysis
The Cisco 9800 WLC has experienced a critical system crash due to a memory leak in the wncd (Wireless Network Control Daemon) process running on firmware version 17.9.4. The memory leak has caused the controller to become completely unresponsive, bringing down the CAPWAP control plane and forcing 60 access points into standalone mode. Without HA SSO configured, there is no failover capability, resulting in complete wireless network outage.
Remediation Plan
1. Attempt power cycle/reboot of the WLC-01 device (10.10.100.10) to clear memory leak and restore basic functionality. 2. Once accessible, collect and analyze the core dump for detailed failure analysis. 3. Check current firmware version and plan upgrade from 17.9.4 to latest stable release addressing known memory leak issues. 4. Configure HA SSO with secondary WLC to prevent future single points of failure. 5. Monitor wncd process memory utilization post-recovery. 6. Verify all 60 APs rejoin the controller after restoration.
Tested: 2026-03-30Monitors: 3 | Incidents: 3Test ID: cmncjlosz02hrobqe5yc0g4em