Troubleshoot WLAN configuration and client connectivity (GUI only)

3.3 Wireless

📘CCNP Encore (350-401-ENCORE-v1.1)

This topic focuses on troubleshooting wireless LANs (WLANs) using the GUI tools provided by Cisco, such as Cisco Wireless LAN Controllers (WLCs) and Cisco DNA Center GUI. You will not be using CLI commands for this exam section. The goal is to identify issues with WLAN configuration and client connectivity and know how to resolve them.

1. Key Areas to Troubleshoot in WLAN

When troubleshooting WLANs, the main areas to focus on are:

WLAN Configuration Issues
- SSID misconfigurations
  - Wrong SSID name
  - Incorrect VLAN assignment
- Security settings mismatch
  - WPA2/WPA3 settings not aligned with client
  - Wrong PSK (pre-shared key) entered
  - Mismatched 802.1X authentication settings
- Radio settings issues
  - Incorrect 2.4 GHz / 5 GHz band settings
  - Channel assignment conflicts
  - Transmit power set too low
Client Connectivity Problems
- Association problems
  - Client cannot see the SSID
  - Client can see the SSID but cannot join
- IP address issues
  - DHCP not assigning addresses
  - VLAN mismatch causing wrong subnet
- Authentication failures
  - Incorrect username/password
  - Certificate errors for enterprise Wi-Fi
- Roaming issues
  - Client not switching smoothly between APs
  - Dropped connections during movement
AP (Access Point) Status
- AP not joined to the controller
- AP in the wrong mode (local vs. flexconnect)
- AP software version mismatch
- AP radio disabled accidentally

2. Using GUI Tools for Troubleshooting

The exam focuses only on GUI-based troubleshooting, not CLI. Here’s how you can use GUI tools effectively:

a) Dashboard Overview

What to check:
- Overall WLAN status (up/down)
- Number of APs connected
- Number of clients connected per WLAN
- Alerts or warnings (like APs down or rogue devices)
How it helps: Quickly tells if the WLAN is operational or if there’s a widespread issue.

b) WLAN Configuration Pages

Check WLAN settings in GUI:
- SSID name and profile
- Security type (WPA2/WPA3, PSK, 802.1X)
- VLAN assignment
- Radio policy (2.4 GHz, 5 GHz, or both)
Common GUI checks for exam:
- Ensure VLAN matches network design
- Security settings match client capability
- WLAN is enabled

c) Client Troubleshooting Pages

Client List: Shows all clients connected to the WLAN
- Status (associated, authenticated, IP assigned)
- Connected AP
- Signal strength (RSSI) and noise
Client Detail Page: For a single client
- Connection history
- Authentication steps (802.1X/PSK)
- IP assignment
- Roaming history
Use case: If a client cannot connect:
- Check if client sees SSID
- Verify authentication is successful
- Verify DHCP is assigning correct IP

d) AP Troubleshooting Pages

AP Status Page: Shows all APs managed by the WLC
- Join status
- Software version
- Radio status (enabled/disabled)
AP Detail Page: For a specific AP
- Number of clients connected
- Radio frequency usage
- Alerts or errors (e.g., cannot join WLC)

e) Event Logs / Alerts

GUI logs help identify:
- Failed client authentication
- AP joining issues
- Interference or coverage problems
Use case: If clients cannot connect in one area, check AP logs for errors.

3. Step-by-Step GUI Troubleshooting Workflow

When troubleshooting WLAN connectivity in the exam, follow a structured workflow:

Check WLAN Status
- Is the WLAN enabled?
- Is the SSID broadcast active?
Check AP Status
- Are APs connected to the WLC?
- Are radios enabled and in the correct mode?
Check Client Status
- Can the client see the SSID?
- Is the client associated with the correct AP?
- Verify RSSI and signal quality
Check Security and Authentication
- Verify WLAN security type matches client settings
- Check 802.1X/PSK configuration
- Check RADIUS/AAA server logs if enterprise authentication is used
Check IP Connectivity
- Ensure VLAN assignment is correct
- Check DHCP server status
- Verify client received a proper IP address
Check Logs and Alerts
- Look for warnings or errors
- Focus on repeated errors for APs or clients

4. Common GUI Issues and How to Spot Them

Issue	GUI Clues	Action
Client cannot see SSID	WLAN disabled or SSID hidden	Enable WLAN or check SSID broadcast
Client cannot authenticate	802.1X failure or PSK mismatch	Correct authentication settings
Client IP not assigned	DHCP failure shown in client details	Verify DHCP server or VLAN assignment
AP not joining WLC	AP status shows “Not Joined”	Check AP IP, management VLAN, WLC reachability
Low signal / poor coverage	Client RSSI very low	Check AP placement, radio settings

5. Tips for the Exam

Always think GUI-first: The exam will provide screenshots or GUI pages for you to analyze.
Look at status indicators: Green = OK, Yellow = Warning, Red = Critical.
Check multiple layers: WLAN config → AP → Client → IP → Security
Follow a structured workflow: This reduces mistakes and ensures nothing is missed.
Focus on details: SSID, VLAN, security type, AP join status, client IP and authentication.

✅ Summary

To pass the exam for 3.3.e, you must:

Understand WLAN components: WLAN, APs, clients.
Know how to navigate the GUI of Cisco WLC or DNA Center.
Identify common problems: WLAN config errors, AP issues, client connectivity issues.
Troubleshoot systematically using GUI pages: Dashboard → WLAN → AP → Client → Logs.
Use GUI information to solve connectivity issues, without needing CLI commands.