liminfoWi-Fi Reference
Free reference guide: Wi-Fi Reference
About Wi-Fi Reference
The Wi-Fi Reference is a searchable cheat sheet covering the complete IEEE 802.11 wireless networking ecosystem from legacy 802.11a/b/g through modern Wi-Fi 7 (802.11be). It provides specifications for each standard including frequency bands, maximum throughput, modulation schemes, and key technologies: Wi-Fi 4 (802.11n) introduced MIMO and 40MHz channel bonding, Wi-Fi 5 (802.11ac) brought MU-MIMO and 160MHz channels with 256-QAM, Wi-Fi 6 (802.11ax) added OFDMA, 1024-QAM, TWT power saving, and BSS Coloring, while Wi-Fi 7 (802.11be) delivers 320MHz channels, 4096-QAM, Multi-Link Operation (MLO), and 16 spatial streams for up to 46Gbps theoretical throughput.
The security section compares WPA2-Personal (PSK with AES-CCMP), WPA2-Enterprise (802.1X/RADIUS with EAP protocols), WPA3 (SAE handshake with offline dictionary attack defense and individual data encryption), and OWE (Opportunistic Wireless Encryption for open networks). Channel planning entries cover 2.4GHz non-overlapping channels (1, 6, 11), 5GHz UNII band allocations with DFS radar detection requirements, and channel bonding from 20MHz through 160MHz. The antenna section explains dBi gain levels, dBm power and signal strength thresholds (-30 to -90 dBm), MIMO configurations (SU-MIMO vs MU-MIMO), and beacon frame parameters.
Troubleshooting entries provide signal strength assessment via RSSI values, channel interference analysis commands, and Wi-Fi analysis tool recommendations for Linux, Windows, Android, and iOS. Configuration examples include NetworkManager/wpa_supplicant setup, hostapd access point configuration, and AP optimization best practices (band steering, RTS/CTS tuning, QoS/WMM). All content loads in your browser with no server communication. Six categories are available: Standards, Security, Channels, Antenna, Troubleshooting, and Configuration.
Key Features
- Complete 802.11 standard specifications from 802.11a/b/g through Wi-Fi 7 (802.11be) with throughput, modulation, and key features
- Security protocol comparison: WPA2-Personal, WPA2-Enterprise, WPA3 (SAE), and OWE for open network encryption
- 2.4GHz and 5GHz channel maps with non-overlapping channel recommendations and DFS radar detection rules
- Channel bonding guide: 20/40/80/160/320MHz width options with trade-offs between throughput and interference
- Antenna fundamentals: dBi gain levels, dBm signal strength thresholds, SU-MIMO vs MU-MIMO configurations
- Signal troubleshooting: RSSI quality assessment (-30 to -90 dBm scale), interference analysis, and diagnostic tool list
- Linux Wi-Fi configuration: nmcli, wpa_supplicant, and hostapd AP setup with complete config file examples
- AP optimization checklist: non-overlapping channel selection, TX power tuning, band steering, and QoS/WMM settings
Frequently Asked Questions
What is the difference between Wi-Fi 5, Wi-Fi 6, and Wi-Fi 7?
Wi-Fi 5 (802.11ac, 2013) operates on 5GHz only with MU-MIMO, up to 160MHz channels, 256-QAM, and 8 spatial streams for a theoretical 6.9Gbps. Wi-Fi 6 (802.11ax, 2020) adds 2.4GHz support, OFDMA for efficient multi-user scheduling, 1024-QAM, Target Wake Time (TWT) for battery savings, and BSS Coloring for interference management, reaching 9.6Gbps. Wi-Fi 7 (802.11be, 2024) introduces the 6GHz band, 320MHz channels, 4096-QAM, Multi-Link Operation for simultaneous multi-band connections, and 16 spatial streams for up to 46Gbps.
Which Wi-Fi security protocol should I use?
Use WPA3 if all your devices support it - it provides SAE (Simultaneous Authentication of Equals) which defends against offline dictionary attacks and ensures individual data encryption. For enterprise environments, WPA2/WPA3-Enterprise with 802.1X/RADIUS and EAP-TLS certificates is the strongest option. If you must support older devices, WPA2-Personal with a strong passphrase and AES-CCMP is still acceptable. For public hotspots, OWE (Wi-Fi Enhanced Open) provides encryption without requiring a password. Never use WEP or WPA (TKIP) - both are broken.
What are the best 2.4GHz channels to use?
In the 2.4GHz band, only channels 1, 6, and 11 are non-overlapping (each channel is 20MHz wide but spaced only 5MHz apart, causing overlap). Always use one of these three channels. To choose the best one, scan for nearby access points and select the channel with the least congestion. In dense environments, the 5GHz band is preferred because it offers many more non-overlapping channels (up to 25 channels in the UNII bands) with less interference.
What is DFS and how does it affect 5GHz channels?
DFS (Dynamic Frequency Selection) is a regulatory requirement on certain 5GHz channels (UNII-2: channels 52-64 and UNII-2 Extended: channels 100-140) that share spectrum with weather and military radar. Access points on DFS channels must perform a 60-second Channel Availability Check (CAC) before transmitting and must immediately switch channels if radar is detected. DFS channels often have less congestion since many consumer devices avoid them, but the channel-switch delay can briefly interrupt connections.
What do the RSSI signal strength values mean?
RSSI (Received Signal Strength Indicator) is measured in dBm: -30 to -50 dBm is excellent (very close to AP), -50 to -67 dBm is good (reliable for all applications), -67 to -70 dBm is fair (adequate for web browsing and email), -70 to -80 dBm is weak (may experience slowdowns and packet loss), and below -80 dBm is unstable (frequent disconnections likely). For voice and video applications, aim for at least -67 dBm. You can check signal strength on Linux with "iw dev wlan0 link".
What is channel bonding and when should I use wider channels?
Channel bonding combines adjacent 20MHz channels to increase throughput: 40MHz (2 channels, Wi-Fi 4+), 80MHz (4 channels, Wi-Fi 5+), 160MHz (8 channels, Wi-Fi 5 Wave 2+), 320MHz (Wi-Fi 7). Wider channels provide more bandwidth but are more susceptible to interference and leave fewer available channels for other networks. Use 40MHz maximum in the 2.4GHz band (only if congestion allows), 80MHz as the default for 5GHz, and 160MHz only when the environment is clean. In dense deployments, narrower channels with less interference often outperform wider congested channels.
How do I set up a Linux access point with hostapd?
Create /etc/hostapd/hostapd.conf with: interface=wlan0, ssid=YourNetwork, hw_mode=g (for 2.4GHz) or a (for 5GHz), channel=6, wpa=2, wpa_passphrase=YourPassword, wpa_key_mgmt=WPA-PSK, rsn_pairwise=CCMP. Then start hostapd with the config file. You also need to configure a DHCP server (dnsmasq or isc-dhcp-server) and enable IP forwarding if you want NAT. The reference provides the complete configuration template with all required parameters.
How do I optimize my Wi-Fi access point performance?
Start by scanning for channel congestion and selecting a non-overlapping channel (1/6/11 for 2.4GHz, any uncrowded channel for 5GHz). Adjust transmit power to cover your area without bleeding into neighboring spaces. Enable band steering to push dual-band clients to 5GHz where there is more capacity. Configure RTS/CTS thresholds to reduce hidden node problems in larger deployments. Enable QoS/WMM to prioritize voice and video traffic. For dense environments, use 20MHz channels on 2.4GHz and 40-80MHz on 5GHz to balance throughput and co-channel interference.