A dual-band AP sends the same network name on 2.4 GHz and 5 GHz, and the client picks which one to join. Many pick 2.4 GHz because its signal looks stronger. Band steering is the AP nudging that choice. Pick a client and a steering method, move the client away from the AP, and watch the frames that decide where it ends up.
One AP, two radios, one network name
The client, not the AP, decides which band to join. The AP can only influence it: by not answering, by refusing, or by asking the client to move. Band steering is each vendor's own logic, built from those standard frames; the name and the rules are not in IEEE 802.11.
1 · The client and the AP
Client
Steering method
Drag the client along the floor. The shading shows where the AP hears its 5 GHz probes above the threshold, and so tries to steer it.
2 · What goes over the air
3 · Where steering pays off
AP → client
Client → AP
2.4 GHz, 20 MHz5 GHz, 40 MHzThe AP steers to 5 GHz hereClick a chart to move the client.
Definitions
↗ opens a term's full entry in the Wi-Fi Glossary, which explains over 400 Wi-Fi terms with their IEEE 802.11 references.
Notes
Not an IEEE feature: band steering is vendor logic, and every vendor names and tunes it differently. What the standard does define are the frames it uses. An AP that receives a matching probe request shall send a probe response (IEEE 802.11-2024 11.1.4.3.4), so hiding responses bends that rule on purpose. An AP may refuse authentication or association with status code 82, REJECTED_WITH_SUGGESTED_BSS_TRANSITION (IEEE 802.11-2024 Table 9-80), and add neighbor reports; a Wi-Fi 6 (HE) client that tries the same network again shall pick an AP from that list (IEEE 802.11-2024 11.3.8). Vendors differ in which status code they send. An AP may send an unsolicited BSS Transition Management request only to a client that sets the BSS Transition bit, bit 19 of its Extended Capabilities (IEEE 802.11-2024 11.21.7.3, IEEE 802.11-2024 Table 9-192; frame format in IEEE 802.11-2024 9.6.13.9).
Hiding probe responses doesn't hide the network: the AP still sends 2.4 GHz beacons, so a client that scans passively, or remembers an earlier 2.4 GHz result, can still try to join there. That is why vendors often combine it with refusing association on 2.4 GHz.
The AP must learn the client is dual-band first: it only knows once it has heard the client's probe on 5 GHz. The sequence assumes it has, from an earlier scan; vendors remember clients for a while. A client seen for the first time, or one whose 5 GHz probes are too weak to hear, looks 2.4 GHz-only and isn't steered.
Disassociation Imminent: a BTM request can also warn that the AP will disconnect the client (the Disassociation Imminent bit, IEEE 802.11-2024 9.6.13.9). Some vendors then do disconnect a client that doesn't move. That forces the move, but the client loses its connection for a moment.
Modelled client behaviour (not from the standard; real clients vary by make, model and driver): clients pick the strongest band they got an answer from, except the older dual-band client, which prefers 2.4 GHz. When 2.4 GHz probes go unanswered, the phone and laptop take the 5 GHz answer at once, while the older client scans 3 times before it settles for 5 GHz. When refused on 2.4 GHz, the Wi-Fi 6 phone moves at once; the laptop and older client try 3 times in total before they try 5 GHz. Each extra scan or try adds about 0.5 s. A client accepts a BTM request only if it hears 5 GHz at −78 dBm or better. Many recent clients also prefer 5 GHz on their own when it is strong enough, which makes steering less needed than it once was.
Simplified radio model: the AP sends 17 dBm through a 3 dBi antenna on both bands; the client sends 15 dBm with a 0 dBi antenna. Path loss is free-space loss over the first metre (2437 MHz or 5180 MHz), then an indoor exponent of 3.5, with no walls. Walls cost more at 5 GHz, which would bring the crossover closer. Noise is −94 dBm at 20 MHz and −91 dBm at 40 MHz (7 dB noise figure). The AP hears a probe down to −90 dBm (4 dB above the 20 MHz noise). Speeds are PHY rates for 802.11ax, 2 spatial streams, 0.8 µs guard interval: 2.4 GHz at 20 MHz, 5 GHz at 40 MHz. 2.4 GHz is also usually busier, with fewer channels and more interference, which this model leaves out.
Beyond this tool: steering clients to 6 GHz uses the reduced neighbor report instead, and moving clients between APs to share the load is roaming, not band steering.