A structured lesson workspace with readable content, hands-on examples, and a clean path to completion.
Sample client diagnostic output showing signal quality, channel, and interference conditions. This is the kind of data you get from a Wi-Fi analyzer or from the WLC's client detail page. Reading it fluently is what separates an RF engineer from someone who just reboots APs.
Client: laptop-12345 (aa:bb:cc:dd:ee:ff)AP: ap-floor3-05 (10.10.20.105)Band: 5 GHzChannel: 44Signal: -62 dBmNoise floor: -95 dBmSNR: 33 dBData rate: 780 Mbps (VHT80, 3 spatial streams)Retries: 2%Channel utilization: 34%RSSI history: -58 → -62 → -67 over 10 minutesClient roaming history: 3 APs in last hour
Signal at -62 dBm is good (aim for -65 or better). SNR of 33 dB is comfortable (25 dB is the floor for reliable data). Channel utilization of 34% is moderate (above 60% indicates congestion). The concerning piece: signal is dropping 9 dB over 10 minutes while the client has roamed three times. Something is moving — either the client or something attenuating the path.
| Layer | Symptoms | Tools |
|---|---|---|
| RF (Layer 1) | No signal, weak signal, intermittent drops | Wi-Fi analyzer, WLC RF stats |
| Association (Layer 2) | Sees SSID but can't associate | Client logs, WLC association logs |
| Authentication (Layer 2/3) | Fails after SSID selection | RADIUS logs, WLC auth logs |
| DHCP (Layer 3) | Associates but no IP | DHCP server logs, WLC client detail |
| Routing (Layer 3) | Has IP but can't reach network | Ping, traceroute |
| Performance | Works but slow | Throughput test, RF analysis |
Sticky clients are the most common wireless performance problem. The client stays associated with a distant AP even when a closer one is available, because its roaming threshold is too aggressive. Modern APs use 802.11k/v to help clients make better roaming decisions — providing neighbor lists and threshold hints. If roaming is still poor, the client is often the limiting factor.
Users in the northeast corner of the fourth floor complain about slow wireless. Wi-Fi analyzer shows -72 dBm signal (weak), 8 APs visible on channel 36 (congested), and 15 dB SNR (low). Other parts of the floor work fine. What's the best approach?
Select the safest next action.
Wireless troubleshooting is RF first, then everything else. If signal and SNR are good, the problem is above Layer 1 — authentication, DHCP, or higher. If signal is bad or SNR is low, no amount of config fixing will help — you need to fix the physical layer (add APs, adjust channels, reduce interference).
Finish the lesson once you have worked through the material. This awards ★ 35 XP.