PlantUML DiagramWireless Troubleshooting Decision Tree
A structured lesson workspace with readable content, hands-on examples, and a clean path to completion.
Monday morning. Users on the fourth floor complain they can't connect to Wi-Fi. Signal strength shows full bars on their laptops. They can see the SSID. They just can't get an IP address. The AP is up and broadcasting. What's the diagnosis?
Wireless problems come in layers just like wired ones — RF (signal), Layer 2 (association, security), and Layer 3 (addressing, routing). Isolating the layer is the first step. 'Can see SSID but can't get IP' is a Layer 2 or Layer 3 problem, not RF.
Signal is fine (full bars). SSID is visible. So RF and association are working. The problem is either authentication or DHCP. Check the client's connection status — does it show 'connected, no internet' or 'authenticating' or 'obtaining IP address'?
If the client can associate but not get an IP, DHCP is failing. In a WLC environment, DHCP requests from wireless clients are relayed by the WLC's virtual interface. If the DHCP server isn't reachable, or the pool is exhausted, or the VLAN doesn't have a DHCP scope, clients sit in 'obtaining IP address' indefinitely.
Clients that hold onto a distant AP when a closer one is available experience poor throughput but don't fail — they just get slow. The client decides when to roam, and many clients roam too late. This is a client-side problem, though the WLC can nudge with 802.11k/v/r for faster, smarter roaming.
802.11k, 802.11v, and 802.11r are the roaming enhancement standards. k gives the client a neighbor list, v allows the network to suggest roams, and r speeds up re-authentication. On modern networks, enabling all three dramatically improves roaming quality for capable clients.
Section 10 complete. You understand WLAN architecture, RF fundamentals, channel planning, security, controller concepts, SSID design, and troubleshooting. Sections 11 (Routing Fundamentals) through 21 (Exam Prep) follow in subsequent batches, covering the full CCNA 200-301 blueprint.
Finish the lesson once you have worked through the material. This awards ★ 30 XP.
Select each vulnerable line, then classify the finding.
Findings
Review target: 9 lines · 3 expected findings