HomeKit Trove & Repository: The Definitive Apple Home Automation Resource

gregatron5 said:

I think 802.11g and WPA2 are du rigueur now. The problem is that limits it to 2.4 GHz, further exacerbated by the fact that many devices don't work on combo 2.5 + 5 GHz networks for inscrutable reasons.

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I bought a couple of things last year which I couldn't connect to my Wifi 6 router until I enabled 802.11b legacy mode and change from WPA2 to WPA.

Of course those devices were probably designed years ago and I just bought things which were antiquated but they don't advertise these kinds of specs, nor was I necessarily looking for them.

I have an old MyQ which wouldn't log into the new 2.4 Ghz network of the new router until I enabled 802.11b legacy mode and WPA -- though I made both changes at the same time so one or the other may be sufficient.

But for something critical like a garage door opener, using a less secure network is more risky than say a smart wifi lamp.

gregatron5 said:

I think 802.11g and WPA2 are du rigueur now. The problem is that limits it to 2.4 GHz, further exacerbated by the fact that many devices don't work on combo 2.5 + 5 GHz networks for inscrutable reasons.

Click to expand...

How can a device not work on 2.4 GHz just because there is a 5 GHz network with the same SSID??

I'd say that anything below 802.11g and WPA2 is not acceptable anymore these days. When 11g was added to a world running 11b, the problem was that g (and everything that came after it, AFAIK) uses ODFM modulation while the original 802.11 and 11b use DSSS. To a 802.11b device 802.11g+ transmissions just look like noise so it's hard to play nice on the same channel. To avoid this, 802.11g in backward compatibility mode first sends a 802.11b packet claiming the channel for some time, and only then transmits a packet using 11g. This means just the presence of an 802.11b system on the channel makes the 11g devices slow down significantly.

However, I gather that this 802.11b compatibility trick is no longer used today so just the presence of 11b shouldn't be a problem, although once 11b transmissions start those use up an inordinate amount of channel capacity so you definitely don't want that.

And WPA is just too insecure.

However, I don't have a problem with stuff being limited to 2.4 GHz. Sure, in an ideal world everything would be able to use the latest standards to their fullest, but extra radios and extra antennas to be able to do this make things harder / more expensive. Having IoT stuff on 2.4 GHz seems like a good choice because that band has better coverage than the 5+ GHz bands, and on 2.4 GHz having slow devices do their thing doesn't really get in the way as nobody in their right mind expects good speeds on 2.4 GHz.

I currently have nine devices connected to my Wi-Fi, with a 2013 MacBook Pro, an iPhone 8, a 2019 iPad Mini, a Raspberry Pi 400 and a 2018 LG TV on "Wi-Fi 5", a new AppleTV 4K and an iPhone SE 3rd gen on "Wi-Fi 6" and everything else on "Wi-Fi 4" (802.11n).

This includes a new printer as well as one from 2015 and a little device hooked up to my electricity meter that sends my power use to the cloud every 10 seconds. This one is connected to my guest network because nothing in my local network needs to talk to it. I'm pretty sure it's 2.4 GHz only, and I'm completely sure it wouldn't be able to connect on 5 GHz anyway as the 2.4 GHz signal is already fairly marginal.

Interestingly, I have two Fibaro homekit devices: an in-wall power switch and a smoke detector. Those connect over Wi-Fi, but interestingly, don't show up in the list of connected devices on my home router. So does this mean that these devices talk to the home hub directly rather than joining the regular Wi-Fi network?

Reading up on Wi-Fi developments over the past two decades, and also informed by the statistics in the post above, I'd say that 802.11n / Wi-Fi 4 is a very good baseline. It's been around for 15 years so it's definitely widely supported and should be cheap to implement now. Unlike earlier standards, it supports both 2.4 and 5 GHz. The speed still holds up fairly well.

Wi-Fi 5 is 5 GHz only and mostly targets improved speed. So not a good fit for IoT. Wi-Fi 6 is all about improving performance on crowded frequency bands, so that's good, and it covers more frequencies, including ones outside 2.4 and 5 GHz, which could be interesting for IoT once there is some level of deployment.

Still, why Wi-Fi for IoT? We now have Matter and Thread. This also runs on 2.4 GHz but it's a mesh network where (powered) devices can forward packets on behalf of other devices, so the network range more or less automatically extends without the need to add additional hubs or repeaters.

iljitsch said:

How can a device not work on 2.4 GHz just because there is a 5 GHz network with the same SSID??

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I wish I knew. Oh how I wish I knew. I've had at least two or three different models of devices give me utter shit for it. Older Wemo plugs and Arlo Baby both state in their manuals to only use 2.4 GHz networks, not commingled 2.4 + 5 GHz networks. And because at the time I was using an Orbi, which doesn't have an IoT network nor does it let you shut off the 5 GHz band (though it does let you turn off the 2.4 GHz band!), I had to go to the advanced router settings on the router's admin web page, power down the 5 GHz radio to 25%, connect devices, then turn the 5 GHz transmission power back up. After that it worked mostly fine. ¯⁠\⁠⁠(⁠ツ⁠)⁠⁠/⁠¯ Icing on the cake with the Arlo Baby camera is at the time it was still effectively made by Netgear. So Netgear's products didn't work with Netgear products. Fun times.