Campus Access Wireless and Mobility
Wireless questions focus on RF design, AP/controller roles, roaming, and security. Know the architecture: APs terminate to a controller or gateway/conductor model, with a conductor managing configuration and controllers handling data. Understand CAPWAP-style control/data separation conceptually: control traffic to the manager, client data forwarding per design (centralized vs. local/bridge).
RF fundamentals: channels and overlap (2.4 GHz uses 1/6/11 non-overlapping; 5 GHz offers many more), channel width trade-offs (wider = more throughput but more airtime contention and fewer channels), transmit power balance (too high power causes sticky clients and co-channel interference), and band steering to move capable clients to 5 GHz. Roaming: clients decide to roam; the infrastructure should support fast roaming (802.11r/k/v concepts) and consistent security so reassociation is quick. Coverage design targets signal and SNR, not just "APs per floor."
Traps: assuming more APs always means better performance (channel reuse and co-channel interference matter); confusing coverage holes with capacity problems; forgetting that a client sticks to a weak AP if power is mismatched; and mixing up which component holds configuration versus which forwards client traffic. Also watch for WPA2/WPA3 Enterprise differences - enterprise uses 802.1X/RADIUS, personal uses a pre-shared key.
Rule of thumb: design for capacity and SNR, keep 2.4 GHz narrow and mostly for legacy/IoT, favor 5 GHz for clients, and keep AP transmit power moderate so clients roam to the nearest AP rather than clinging to a distant one.