Rainer,
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Thank you for your reply, and sorry I can't get to everyone's reply timely.
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On Tue, Apr 1, 2025 at 04:22 AM, Rainer Hantsch wrote:
I installed many WiFi networks in my life, but I would never go above 30-40 clients on one Access Point (AP). More clients may work, but with huge impact on throughput, but it is also possible that the accesspoints cannot handle that number of MAC addresses.
I would also never install wireless repeaters (only repeating over WiFi). Every intermediate repeater reduces the throughput, so when you have 3~4 cascaded ones the construct can become very unstable ...
Thanks. I'm unfortunately well aware of the MAC address limits. The Ubiquiti APs I use advertise being able to support 200 to 350 clients each. I tested this, but this is not reality. When I disabled all but one AP, 120 clients on the 2.4 GHz band is the maximum the lone AP could handle. Subsequent connections were rejected, with a smartphone located near the AP getting an authentication error when trying to connect. I filed a case with Ubiquiti and they claim they do this because airtime is likely to become the bottleneck with this many clients. It may be true, but their specs are still false advertising. I don't have nearly enough 5 GHz clients to see if the same MAC address limit applies to that band. I could easily test whether the airtime is the bottleneck by placing 2 APs next to each other on the same channel, and seeing if I can get more than 120 clients to connect, between the two of them. I haven't taken the time, but I strongly suspect I would get >120.
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While the clients are numerous, most of them are lightbulbs, which are very low bandwidth, and support only 2.4 GHz channels. For example, my porch light Wifi bulb, which is connected to Wifi 24/7, averages 135 bps for the last 24 hours in the Unifi controller. A good chunk of that traffic is likely from smokeping that I have been running to track packet loss and latency. I disable/enable smokeping periodically for testing purposes. It significantly increases traffic as it will be pinging all devices, but is not the root cause of the Wifi problems.
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I am not using repeaters, but I'm using a mesh network, because I only have Ethernet plugs in 2 indoor locations on the same bottom floor, when there are 17 indoor locations to be covered, and many more outdoors (I haven't kept a count).
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I know that there are standards like 802.11r.? Such routers/APs support mesh radio (so they transparently hand over moving clients.? But a warning, I (still) have a few WiFi cameras in use that do not support that. Even worse, the cameras do not connect to this Mesh-WLAN and I had to define a separate VLAN without "r" especially for them.?? I doubt that every little smarthome device will smoothly support Mesh WLANs.
My Ubiquiti APs support 802.11r, and they use it for meshing. The 802.11r feature can be enabled/disabled per-SSID. I was surprised to find that my Samsung Galaxy S22 Ultra does not support this. I discovered by turning off auto-reconnect on the SSID on my phone. It dropped out of Wifi every few minutes. I turned off "Fast roaming", which is Ubiquiti's name for 802.11r on the SSID, and the phone stopped dropping out. You are right that the IoT devices are not going to support this, especially as there are several brands/models of them. I could separate SSIDs, but this gets messy, uses additional airtime, and Ubiquiti has a hard limit on the number of SSIDs on any single AP per radio.
So I would start with having a close look on number and location of APs to not have too many devices connected to a particular AP. In worst case you need to add more APs and lower their signal level to make radio cells smaller.
And use copper backbones (connect every AP to the LAN switch by an individual LAN cable). Copper is LOTS faster than WiFi, and this way you also eliminate concatenated APs/Repeaters.
Currently, I have 2 wired APs, and 7 meshed. Most of the mesh links are 1 hop. There are 2 mesh links that are 2 hops.
It would cost a minimum of $5K to add 5 copper backbones, and in practice likely to be done outdoors, which would be unsightly. Running indoors can't be done inside the walls. It could potentially be done with piercing and many raceways, but I'm not even certain it can. I know the wireless backhaul is much slower, but I don't believe it is the bottleneck here. When I use iperf3 (Magic iperf app) on my Android phone, on a 5 GHz SSID, there is no point on my property where I get less than about 30 Mbps, and that is one wall away from the location of the 2 hop meshed APs, outdoors. That kind of bandwidth is more than sufficient to carry the data for 300 2.4 GHz lightbulbs. Near the 2 wired APs, iperf3 reports about 600-800 Mbps. In many rooms near the single hops, I get 150 - 500 Mbps depending on distance/walls. All of that is much slower than the 10 Gbps copper LAN between the office and home theater, and I would much prefer a copper backbone for all 9 APs, but while I may want to do i eventually, I don't believe it will solve the issue with the large number of 2.4 GHz clients. For the record, this is how the mesh network looks like today, with the vast majority of the Wiz lightbulbs turned off by relay. The Office and Home theater APs are the 2 wired ones. All the other APs are meshed. The double-meshed ones are Bar AP and Master bathroom. Master bathroom has to be double-meshed, as it is in practice out of range of either wired AP - it can technically connect, but will get < 1 Mbps throughput. Bar AP could be changed to single hop, but gets a better signal strength from another mesh AP. The average ping times for those 2-hop APs is under 10ms, so I don't believe the 2-hop are adding too much latency. They are definitely reducing the bandwidth, though.
I have several cases opened with Ubiquiti about problems related to those Tx retries and incorrect channels displayed for some mesh APs. And others related to signal strength/latency, not GUI. Note that all APs have DHCP reservations. These are not dynamic leases. Same for every client device on my IP network, whether Wifi or Wired. I'm using a /22.
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