##
Wi-Fi & 802.11
The wireless standards, the bands they ride on, and the security that protects them.
| Standard | Wi-Fi gen | Max rate | Band / tech |
|---|
| 802.11b | — | 11 Mbps | 2.4 GHz |
| 802.11a | — | 54 Mbps | 5 GHz |
| 802.11g | — | 54 Mbps | 2.4 GHz |
| 802.11n | Wi-Fi 4 | 600 Mbps | 2.4 / 5 · MIMO |
| 802.11ac | Wi-Fi 5 | ~3.5 Gbps | 5 · MU-MIMO |
| 802.11ax | Wi-Fi 6/6E | ~9.6 Gbps | 2.4/5/6 · OFDMA |
| 802.11be | Wi-Fi 7 | ~46 Gbps | 2.4/5/6 · MLO |
// security
| WEP | Broken — never use |
| WPA | TKIP, deprecated |
| WPA2 | AES-CCMP, the standard |
| WPA3 | SAE, forward secrecy |
// facts
- 2.4 GHz: longer range, more interference — channels 1, 6, 11
- 5 GHz: more channels & speed, shorter range
- 6 GHz (Wi-Fi 6E/7): wide clean spectrum
- Personal = PSK · Enterprise = 802.1X / RADIUS
- Autonomous AP vs controller (WLC) over CAPWAP
- SSID = network name · BSSID = AP radio MAC
// bands
| Band | Channels | Width |
|---|
| 2.4 GHz | 3 usable (1·6·11) | 20 / 40 MHz |
| 5 GHz | ~25 (many DFS) | 20–160 MHz |
| 6 GHz | ~59 (Wi-Fi 6E/7) | up to 320 MHz |
// 802.11 frame types
| Management | Beacon, Probe, Auth, (Re)Assoc, Deauth |
| Control | RTS / CTS, ACK, Block-ACK |
| Data | Carries the actual payload |
// joining a network
Beacon / Probe
→ Authentication
→ Association
→ 4-way handshake
WPA2 / WPA3
→ Data