I don't want to dive too deep into Apple's approach to 802.11 other than to say it's what sparked this question. Apple's CoreWLAN setWLANChannel() method allows macOS application to set the NIC wifi channel. setWLANChannel takes BOTH the channel and the channel width (20, 40, 80, 160MHz) as arguments. As in, "I want channel 11 at 20Mhz."

I'm curious if Apple's take on the channel width is a real thing, represented in the PHY layer, and if a particular value captures more or less packets in some environment.

So that's it as far as Apple goes... just framing the questions below.

I'd imagine beacons should reach as many clients as possible. Do APs broadcast beacon frames using a max permissive channel width? If so, what is the max permissive channel width? I'd think narrower is better.

Can beacons ever be missed? This is asked in both terms of 802.11ab/g/n/ac/ax interoperability but also in the sense that some user chooses an ill fated channel and channel width setting. The question assumes the AP and STA both have the same hardware capabilities but possibly different configurations of the PHY layer.

Do access points negotiate channel width individually for each client? As in, given access point Charlie, can stations Delta, Echo, and Foxtrot use a mix of channel widths?

For something like Wireshark monitoring, what channel width captures the most traffic possible? Is it best to use the widest channel width?


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