This simulator models a ceiling-mounted access point and a laptop wireless client sharing a radio channel. Adjust distance, intervening walls, frequency band, transmit power, interference and the number of equal-airtime clients, then watch the client scan, authenticate, associate, complete a key handshake and obtain an IP address before useful data can flow.
• A real-time 3D cutaway of the ceiling access point, laptop wireless client, office partition walls, radio-wave/antenna visualization, additional shared-airtime clients and the wired LAN uplink, with home view, focus-selected-part, toggleable full enclosure, exploded view, auto-rotate, expand and label toggle controls, and numbered parts matching the companion diagram. • An AP-to-client separation slider (1–40 m) and an equivalent-intervening-walls slider (0–4 walls). • A frequency-band selector (2.4 GHz or 5 GHz) and a transmit-power slider (5–23 dBm). • A noise-floor-increase slider (0–35 dB) to model interference, and an equal-airtime active-clients slider (1–8 clients). • A correct-shared-key toggle to model a right or wrong WPA2 passphrase. • Auto-traffic with an adjustable interval (0.5–5 s) and a manual "Send test traffic" action, plus a dedicated "Restart association" (disconnect) action, alongside start/stop trial controls. • Play/pause, single 0.1 s step and 1 s step time controls, plus a playback-speed selector (10x slow motion, real time, 10x, 60x/1 minute-per-second). • Six live metrics: received signal estimate (RSSI), noise floor, signal-to-noise ratio (SNR), association stage, selected illustrative PHY rate, and per-client useful throughput (goodput). • A Curves & measurements tab with two charts (RSSI vs. noise floor; PHY rate vs. goodput), the full model equations, and snapshot readouts. • An Experiments tab with four guided scenarios (connect client, wrong shared key, congested radio, shared airtime), a model-verification bench of independent automated checks, and a timestamped event log with a copyable trial report. • A Learn & assess tab with four guided lessons (find the network, establish permission, obtain an address, budget airtime), a two-question knowledge-check quiz, and a written scope/reference statement citing Cisco's WLAN technology documentation.
The client works through scanning, open-system authentication and association, a WPA2 key handshake, and IP address setup, in that order, before the modeled application frame can be sent — this fixture uses 0.5 s per stage and completes an IP-ready state after 2.5 simulated seconds when the link is viable. If the shared key is wrong, the handshake stage never completes and no usable data connection forms, regardless of how strong the radio signal otherwise is, which is exactly what the wrong-shared-key experiment isolates.
Signal quality is calculated, not just displayed: path loss combines a band-specific reference loss, the distance term 20·log10(distance), and 6 dB for each selected intervening wall, and RSSI is transmit power minus that path loss. SNR is RSSI minus the noise floor, so raising interference or adding walls at long range can push SNR low enough that the client cannot maintain association at all — the congested-radio experiment combines 30 dB of interference, 3 walls and 30 m of separation to demonstrate exactly this collapse.
The equations panel gives goodput as PHY rate × 0.55 × (1 − retry fraction) ÷ clients — meaning the displayed PHY signaling rate (for example 65 Mbps) is never the same as delivered application throughput, because protocol overhead, retries and airtime sharing all reduce it. The shared-airtime experiment holds SNR constant while raising the active-client count to 4, and goodput per client drops to one quarter of the single-client result, illustrating that configured clients split available capacity roughly equally in this model.
This is a representative single-stream 20 MHz 802.11n rate-selection model with illustrative SNR thresholds and 0.5 s stage timing. It does not perform a cryptographic key exchange, ray-traced propagation, real network scanning, roaming or full contention/backoff simulation — every association attempt and interference condition here is generated and evaluated entirely offline.
The client scans for a compatible access point, completes open-system authentication and association, performs a WPA2 key handshake, and then obtains an IP address — in this fixture each stage takes 0.5 simulated seconds, so a viable link reaches an IP-ready state after 2.5 seconds. Only after all of these stages succeed can the modeled application test traffic be sent.
The wrong-shared-key experiment sets an incorrect passphrase while leaving distance, walls and power unchanged. The key-handshake stage never completes without the correct shared key, so no usable data connection forms, regardless of how strong the received signal or how high the calculated SNR is — authentication success and signal quality are independent requirements in this model.
Goodput is calculated as PHY rate × 0.55 × (1 − retry fraction) ÷ active clients, so protocol overhead, retries and airtime shared among clients all reduce delivered throughput below the raw PHY signaling rate. The shared-airtime experiment holds signal quality constant and raises the active-client count to 4, cutting each client's goodput to one quarter of the single-client value, purely from airtime sharing.
This is a representative single-stream 20 MHz 802.11n model with illustrative path-loss, SNR and stage-timing assumptions. It does not perform an actual cryptographic key exchange, ray-traced radio propagation, real access-point scanning, client roaming or full 802.11 contention and backoff simulation — every radio condition, association attempt and fault injection is generated and evaluated entirely offline.