@terho said in iPhone occasionally disconnecting and reconnecting WLAN?:
SOLVED (partially): I studied the potential signal interference. I bought a Netspot software for analysing WLAN signals with my laptop and did find out that the 2.4 GHz signal level was breaking too often, at worst it was completely lost few times within a minute. 5 GHz was ok. Did not find any other transmitters causing interference. But, the access point system log was full of error messages and appearing unhealthy system. The next step was to review the log file with the manufacturer's support service. Eventually this unit was concluded as a faulty AP and they sent me a replacement (warranty period was valid). I now have a new unit in use and signal quality is ok in both bands.
But still, iPhone keeps on disconnecting, but not that frequently. After having googled much more, frequent disconnection seems to be a very common problem everywhere. I think that Apple should fix this, as all the obvious checks do not help (signal quality, distance to AP, router, firewall, DHCP lease time, interference, toggling iPhone Wifi on/off, ... while all other devices connect without problems).
I actually make a living deploying WiFi networks, and my experience tells me it is very unlikely to be the iPhone that's the culprit. However - right now there are rumours of disconnect issues if you are running the latest iOS16 - if that's the case I'm sure it'll be fixed very soon (if not already in 16.1).
Otherwise I would like to question your enterprise AP as well - what brand are we talking about here,?
Because I can tell you: fx. D-Links "enterprise APs" has nothing enterprise about it - it's still a dodgy AP, that at best works, but usually has "issues" that causes some vendor radios to drop every now and then.
See, WiFi is less than perfect - it's not always drivers that remedy problems. Sometimes new chipsets are released, that just does not work properly without firmware "hacks" on the AP side, to allow the chipset to still remain connected. Those continuing hacks and compatibilty fixes are what you buy, when you buy one of the big enterprise vendors AP products.