6 GHz has up to 59 channels, and clients may not send the usual "is anyone there?" probe request, so finding an AP by scanning the band could take seconds. Compare full passive scanning, preferred scanning channels, FILS Discovery and unsolicited probe responses, and the shortcut most clients use: a Reduced Neighbor Report heard on 2.4 or 5 GHz.
Why 6 GHz is different
On 2.4 and 5 GHz a client can send a probe request to the wildcard SSID on each channel and collect the answers. In 6 GHz that is not allowed, so there isn't a storm of probe requests on every channel (IEEE 802.11-2024, 26.17.2.3.3). Instead, the standard gives clients three ways in: listen on the 15 preferred scanning channels (PSCs), where 6 GHz-only APs should live; hear an AP's FILS Discovery frames or unsolicited probe responses, sent at least every 20 TU, instead of waiting 100 TU for a beacon; or learn about the AP before scanning 6 GHz at all, from the Reduced Neighbor Report (RNR) its co-located 2.4 or 5 GHz radio puts in every beacon.
1 · The AP and the client
AP also sends
The client is looking for
Scan order
6 GHz spectrum
Preferred scanning channel (PSC)The AP's channel
2 · Three ways to find it
Each bar is the client's time, one block per channel it listens on, drawn to its own time scale (the table below compares them). The bar ends when the scan has finished, which is usually what decides when the client connects: most clients finish scanning and compare the APs they heard before choosing one. The green mark is when it first hears this AP. Joining (authentication, association and the 4-way handshake) comes after either way.
0 ms
3 · Side by side
4 · Pros and cons
The first three are how a client finds the AP; the last three are what the AP sends to be found. The outlined boxes match your current settings.
How the client finds the AP
What the AP sends between beacons
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
Timing used: a passive scan listens 110 ms per channel, enough to hear one beacon (every 100 TU = 102.4 ms). On a PSC a client looking for a saved network may probe for it once the channel has been idle for 5.484 ms (the minimum of dot11MinPSCProbeDelay) and waits about 10 ms for the answer; a client building a list of any networks listens for 20 TU, long enough to hear FILS Discovery or unsolicited probe responses. Switching channel takes about 1 ms. The AP's frames fall at a random point, so the time to hear one is on average half its interval.
What is optional: scanning every 6 GHz channel is optional: the standard leaves the channel list to the client (the ChannelList of MLME-SCAN.request, IEEE 802.11-2024, 6.5.3.2), and its 6 GHz rules only say what a client may send on a channel it chooses to scan (26.17.2.3.3). FILS Discovery is optional for a tri-band AP, whose clients learn about it from the RNR; a 6 GHz-only AP that wants to be found efficiently must send FILS Discovery frames, unsolicited probe responses or beacons at least every 20 TU (26.17.2.3.2). FILS authentication (the fast initial link setup AKMs) is a separate, optional feature that 6 GHz doesn't require.
Scan order: the standard leaves the order and the time per channel to the client. Linux (mac80211) walks its channel list in order, usually upwards; the firmware in most phones and laptops may reorder it, for example checking the channels of saved or recently seen networks first. Any order (average) puts the AP's channel at the middle of the scan, where it lands on average. The whole-scan time is the same in any order.
Connected clients scan in bursts: a few channels, then back to their own channel to pass traffic, then a few more. The whole scan then takes noticeably longer than the listening times add up to. Many clients also skip blind 6 GHz scanning and visit only the channels RNRs told them about, plus the PSCs.
RNR: the client is assumed to be already on 2.4 or 5 GHz (connected, or in its normal scan), so it hears the RNR in the co-located AP's next beacon, on average half a beacon interval away. If the RNR says unsolicited probe responses are active, the client waits for one (up to 20 TU) instead of probing, as the standard requires; otherwise it probes straight away.
Joining takes about another 20–50 ms on a quiet channel, the same for every method. In 6 GHz, open networks, TKIP and WPA2-Personal (PSK) are not allowed and PMF is required (IEEE 802.11-2024, 12.12.2), so clients join with SAE, 802.1X or OWE; the Wi-Fi Alliance additionally requires SAE to use hash-to-element there. Real clients also spread scans between data traffic, so wall-clock times are often longer.
Sources:IEEE 802.11-2024 26.17.2.3 (6 GHz scanning, PSCs and the probe request rules), 11.45.2.1 (FILS Discovery), 9.4.2.169 and 11.49 (Reduced Neighbor Report), 11.53 (out-of-band discovery: a 2.4/5 GHz AP co-located with a 6 GHz AP shall list it in every beacon and probe response), 12.12.2 (6 GHz security) and IEEE 802.11be-2024 for the RNR's MLD fields. Available 6 GHz spectrum varies by country; see the Wi-Fi Channel Map.