Hi again
I have tried with a Galaxy S8+ (old phone was a Galaxy S7) and now it works perfectly!
I am not sure if the Galaxy S7 was just bad for 802.11r or probably some settings left back by WiFi Manager I used for a while for managing best network pick up.
I have also seen the same iPhone problem you see, try to enable "push R1kh" on all your AP and see if it improves the standby issue
The S7 should actually work. See if you can access the Wifi advance settings menu. I couldn't remember how to do that.
I didn't notice my "push R1kh" settings, seems like I missed on one of the AP.. but it shouldn't affect the iphone. It seems that the AP thinks the IPhone needs to do a full authentication and the iphone thinks it's roaming, that's why it works after a reboot.
Mobility Domain just indicates the APs where no reauthentication is needed. So it's rather bad to separate 2.4 and 5GHz networks with the same SSID by different mobility domains.
WIFI clients are making their roaming decisions by comparing the signal strength of the current network to other known networks. Most clients have a 20dB threshold for roaming, which can by only changed in some clients.
So, if you're having a problem with sticky clients it's better to redesign your WIFI cells to have smaller cells with lower tx power so the cell borders are more definied.
Beside this, seamless roaming works without 802.11r, too. Especially when using PSK there's only a small gain in time of interruption, mostly noticable when making phone calls over WIFI.
I'm pretty sure there wasn't any suggestions or recommendation to have two networks with same SSID AND different mobility domain. Nevertheless, based on your explanation above, it would suggest that it doesn't matter " seamless roaming works without 802.11r" . Have you actually tested this ? e.g. copy a large file from a NAS while roaming ?
Do not confuse mobility with roaming, and do not confuse mobility with "seamless" mobility.
Fantastic idea ...And ideally, you should have your AP in the middle of the room,etc,etc..... if you have the luxury of redesigning your home, moving concrete walls around, etc. Reality strikes and we are back to fixing real world problem with AP on my TV console because that's where the connections are.
I'm using WLAN roaming for many years in my home, without any interruptions when switching cells. File transfers, streaming, VoIP calls, all fine. 802.11r only reduced the small pause gap. In advance, yes, also with IPhones.
802.11r by design doesn't take care of established IP connections. Also it isn't doing any client steering.
I have the luxury of having a lot of APs, but they're also not at optimal positions. But I can reduce tx power at each AP to make its coverage a little bit smaller so my clients are seeing the next, better AP more earlier and thus making an earlier roaming decision. Did you check the signal situation at your critical roaming points where your connections are lost?
As signal intensity decreases nonlinear by 1/r², you can make your cell borders with a small overlap only, that means old signal decreases rapidly while new signal increases rapidly over a small range. Cell coverage can be influced by position and tx power. If you cannot place your APs with only small cell overlap at full power, you can reduce tx power to optimize cell overlap. Try to imagine at which rate (db per meter) your signals decrease or increase, so you'll see who far you have to move to get a clear difference in signal strength for roaming.
When your client is seeing more that 1 known network it stays at the already connected network until another network has a better signal than the usual threshold of 20dB (20dB is representing the difference in signal strength of both networks, otherwise I would write dBm 
).
20dB is the threshold of many wifi drivers, you'll find references in Broadcom and Atheros driver source or just the documentation to Intels wifi drivers for Windows. It's not standardised in 802.11
PS: To cover up the initial post: No problem with my iPhone 5s and 802.11r enabled, here. Did you try with 802.11r disabled, also? I know, that my iPhone is very sticky to connected networks and is roaming later than other devices.
I'm using WLAN roaming for many years in my home, without any interruptions when switching cells. File transfers, streaming, VoIP calls, all fine. 802.11r only reduced the small pause gap. In advance, yes, also with IPhones.
802.11r by design doesn't take care of established IP connections. Also it isn't doing any client steering.
I have the luxury of having a lot of APs, but they're also not at optimal positions. But I can reduce tx power at each AP to make its coverage a little bit smaller so my clients are seeing the next, better AP more earlier and thus making an earlier roaming decision. Did you check the signal situation at your critical roaming points where your connections are lost?
Hi
Actually you are confusing things here: the 802.11r is an advanced roaming technique, it not only improve the re-authentication time between APs, but also it avoid that the network interface get an down/up event that always come with a normal AP disconnect-reconnect. The down/up will cause the drop of all the established TCP connection, so in case of file transfer (such file copy, local video stream, ecc..) they will stop. VoIP, Netflix, and such "may" auto recover, thanks to their protocol, but this is another story
Nope, roaming without connection losses was possible before 802.11r was introduced. A client connect/disconnect doesn't cause the interface to get up or down. Would be totally silly to bring an interface down when 1 of 30 clients is disconnecting.
802.11r only speeds up the negotation between access point and client primarily to avoid short dropouts in VoIP calls. If you're using RADIUS authentication, you can see this effect at best.
Please have a look in to the corresponding IEEE standard paper.