Wi-Fi Technology, Standards, and Certifications
This domain tests how well you know the IEEE 802.11 family, the organizations behind Wi-Fi, and the certification landscape. Expect questions that match a standard to its band, modulation, or headline data rate, and that separate IEEE standards from Wi-Fi Alliance programs.
Standards and bands
- The original 802.11 (1997) ran at 1 and 2 Mbps in 2.4 GHz. 802.11b added DSSS at up to 11 Mbps in 2.4 GHz. 802.11a used OFDM in 5 GHz at up to 54 Mbps; 802.11g brought OFDM to 2.4 GHz at up to 54 Mbps.
- 802.11n introduced MIMO in 2.4 and 5 GHz and reaches 600 Mbps with four spatial streams and 40 MHz channels. 802.11ac is 5 GHz only, uses wider channels and MU-MIMO, and tops out near 6.93 Gbps. 802.11ax (Wi-Fi 6) adds OFDMA and works in 2.4, 5, and 6 GHz; 802.11be is Wi-Fi 7.
- IEEE writes the 802.11 MAC and PHY standards. The Wi-Fi Alliance certifies interoperability and owns the Wi-Fi CERTIFIED, WPA2, and WPA3 programs. Regulatory bodies such as the FCC, ETSI, and ISED set channel and power rules.
Names and certifications
Know BSS, BSSID, ESS, SSID, AP, STA, and DS. The CWNP track runs CWTS, CWNA, then CWSP, CWDP, or CWAP, and finally CWNE. A vendor certification is not a standards certification. 802.11i defines robust security; 802.11k, 802.11v, and 802.11r support roaming. These amendments are often tested as feature names rather than as standalone standards.
Worked example
A question asks which standard first brought OFDM to 2.4 GHz. Reasoning: 802.11a used OFDM but only in 5 GHz; 802.11g applied OFDM in 2.4 GHz while keeping DSSS compatibility. Answer: 802.11g.
Traps
Do not assume 802.11ac operates at 2.4 GHz. Do not treat 54 Mbps as an 802.11b rate. Do not call the Wi-Fi Alliance the author of IEEE 802.11. Headline rates assume best-case channel width, spatial streams, and coding, not real-world throughput.